Compositions containing cellulose nanofibrils and lignin or their complexes, and process for the production of lignocellulose-derived materials

Abstract

The present invention provides a composition comprising cellulose nanofiber and lignin or a complex thereof for efficiently utilizing lignocellulosic biomass without a residue, and a method for efficiently producing a lignocellulose-derived material from lignocellulosic biomass. The present invention relates to a composition comprising cellulose nanofiber having a sulfate group and a lignin-derived substance, and a method for producing a lignocellulose-derived material.

Description

Technical Field

[0001] This invention relates to compositions comprising cellulose nanofibers (also known as “CNF”) and lignin or complexes thereof, and methods for manufacturing materials derived from lignocellulose. Background Technology

[0002] With increasing environmental awareness, research is underway worldwide aimed at the practical application of biomass-derived materials. For example, when using lignocellulosic biomass such as wood (wood chips, etc.), herbs, coconut shells, and nut shells as raw materials, if the cellulose, lignin, and hemicellulose that are its constituent elements can be used industrially without any residue, it will make a significant contribution to both circular resource utilization and CO2 immobilization.

[0003] Cellulose, when formulated into nano-sized cellulose such as cellulose nanofibers and cellulose nanocrystals (also known as "CNC"), is associated with improvements in various physical properties such as strength, flexibility, and elongation when combined with resins, rubber, and concrete, and is attracting attention as a novel environmentally suitable material.

[0004] When lignin undergoes depolymerization (decomposition) while inhibiting the condensation of β-O-4 bonds, it can yield low-molecular-weight lignin monomers (also known as "monolignols") and higher-molecular-weight lignin oligomers. Monolignols, besides being used as various phenolic derivatives, can also be used as fragrances such as vanillin. Both lignin oligomers and undepolymerized lignin themselves possess phenolic resin skeletons, therefore, research is underway on their material applications in blends with resins and rubbers, as well as their use as monomers.

[0005] For example, Patent Document 1 describes a method for manufacturing cellulose nanofibers by directly producing cellulose nanofibers from lignocellulose.

[0006] Patent document 2 describes sulfated cellulose nanofibers and a method for manufacturing the cellulose nanofibers.

[0007] Patent document 3 describes a method for recovering cellulose, lignin oligomers, monolignin alcohols and hemicellulose from lignocellulose.

[0008] Patent document 4 describes a method for manufacturing cellulose nanocrystals from lignocellulose.

[0009] Thus, in the process of studying the separation, manufacturing methods and uses of the various components of lignocellulosic biomass, research was also conducted on the utilization of biomass without any waste.

[0010] For example, in Non-Patent Literature 1, a study was conducted on a composite of cellulose nanofibers and lignin.

[0011] Non-patent literature 2 presents a study on a composite of cellulose nanocrystals and lignin.

[0012] Existing technical documents

[0013] Patent documents

[0014] Patent Document 1: Japanese Patent Application Publication No. 2008-308802

[0015] Patent Document 2: Japanese Patent Application Publication No. 2020-41255

[0016] Patent Document 3: International Publication No. 2017 / 178513

[0017] Patent Document 4: International Publication No. 2012 / 014213

[0018] Non-patent literature

[0019] Non-patent literature 1: Wangxia Wang et al., “Lignin Redistribution for Enhancing Barrier Properties of Cellulose-Based Materials,” Polymers 2019, 11, 1929

[0020] Non-patent literature 2: Umesh Agarwal et al., "Production of high lignin-containing and lignin-free cellulose nanocrystals from wood," Cellulose, 2018, 25, 5791 Summary of the Invention

[0021] The technical problem that the invention aims to solve

[0022] However, various technical problems exist in order to utilize lignocellulosic biomass without waste.

[0023] For example, TEMPO oxidized cellulose nanofibers and sulfated cellulose nanofiber monomers derived from lignocellulose, as described in Patent Documents 1 and 2, lack formability. Furthermore, their compatibility with materials such as resins and rubber is insufficient when they are compounded together.

[0024] The cellulose nanofibers in Non-Patent Literature 1 are unmodified cellulose nanofibers, therefore their interaction with lignin is weak, and the strength of the composite is insufficient.

[0025] [Chemical Formula 1]

[0026]

[0027] (The fine dashed lines indicate a weak interaction between unmodified cellulose and lignin.)

[0028] Furthermore, the cellulose nanocrystals in Non-Patent Literature 2 are short and rigid, so the composite of cellulose nanocrystals and lignin is more prone to becoming brittle compared to the composite of cellulose nanofibers and lignin.

[0029] Furthermore, in the methods for manufacturing nanocellulose described in Patent Documents 3 and 4, the raw material is typically a substance obtained by separating pulp and lignin components from lignocellulose through cooking methods such as the KP method and DP method. In this method, when manufacturing cellulose nanofibers, drying, chemical treatment, and filtration-washing processes of cellulose are required, thus consuming considerable time and energy. Additionally, in the case of manufacturing cellulose nanocrystals, the acid hydrolysis reaction of cellulose is time-consuming, leading to increased manufacturing costs. Moreover, the KP and DP methods used for separating pulp and lignin components involve the condensation reaction of unstable lignin components, significantly reducing the yield of highly valuable monolignin alcohols.

[0030] Therefore, in order to improve the yield of monolignin alcohol, a method was studied to fully swell lignocellulose with solvents and the like, and to protect the hydroxyl groups (OH groups) of lignin-derived substances to inhibit the condensation of β-O-4 bonds. In Patent Document 3, as a method to protect the OH groups of lignin-derived substances, it is described that the OH groups of lignin-derived substances undergo an acetal reaction with protecting groups such as aldehydes and ketones.

[0031] However, the acetal reaction described in Patent Document 3 is an equilibrium reaction. Therefore, if the initially added aldehydes, ketones, and other protecting groups are consumed due to the protection of the OH groups of lignin-derived substances in the acetal reaction, the chemical equilibrium is prone to deprotection. In order to make this chemical equilibrium lean towards protection, it is also considered to add an excessive amount of aldehydes, ketones, and other protecting groups. However, aldehydes, ketones, and other protecting groups will inhibit the swelling of lignocellulose. Therefore, as a result, the yield of monolignin alcohols cannot be improved.

[0032] Figure 1 The text outlines a method based on existing technologies for the parallel production of lignocellulose-derived materials from lignocellulose-based biomass, namely, the sulfation of CNF, CNC, hemicellulose, and monolignin alcohols.

[0033] Therefore, the technical problem of the present invention is to provide a composition comprising cellulose nanofibers and lignin or a composite thereof for the wasteless utilization of lignocellulosic biomass, and a method for efficiently producing materials derived from lignocellulosic biomass.

[0034] means of solving technical problems

[0035] As mentioned above, cellulose nanofibers lack formability when used alone. On the other hand, even when composites are prepared by combining cellulose nanofibers with lignin-derived substances, the interaction between the cellulose nanofibers and the lignin-derived substances is weak, resulting in weak composite strength, especially when the cellulose nanofibers are unmodified cellulose nanofibers (containing OH groups), TEMPO-oxidized cellulose nanofibers (containing carboxyl groups (COOH groups)), or phosphate-esterified cellulose nanofibers (containing phosphate groups).

[0036] [Chemical Formula 2]

[0037]

[0038] (In the formula, the thin dashed line represents a weak interaction between TEMPO-oxidized cellulose and lignin, and M represents a cation with a valence of 1 to 3.)

[0039] [Chemical Formula 3]

[0040]

[0041] (In the formula, the thin dashed line represents a weak interaction between phosphorylated cellulose and lignin, and M represents a cation with a valence of 1 to 3.)

[0042] Therefore, the inventors conducted in-depth research and found that by using cellulose nanofibers with sulfate groups (also known as "sulfated cellulose nanofibers") as cellulose nanofibers, the interaction between cellulose nanofibers and lignin-derived substances in the complex of sulfated cellulose nanofibers and lignin-derived substances (also known as "sulfated cellulose nanofiber-lignin-derived substance complex") can be enhanced, thereby improving formability.

[0043] [Chemical Formula 4]

[0044]

[0045] (In the formula, the thick dashed line indicates a strong interaction between sulfated cellulose and lignin, and M represents a cation with a valence of 1 to 3.)

[0046] Furthermore, the inventors have discovered that when manufacturing materials derived from lignocellulose from lignocellulose biomass, by simultaneously performing chemical treatment (sulfation treatment) of cellulose with a lignin-derived substance used to suppress the condensation reaction of lignin in lignocellulose biomass, the manufacturing of such biomass-derived materials can be achieved with lower energy consumption and shorter production time.

[0047] Furthermore, the inventors have discovered that by carrying out a protective reaction of the OH groups of lignin-derived substances in the presence of dimethyl sulfoxide (DMSO) and acetic anhydride or propionic anhydride as solvents, the OH groups of lignin-derived substances can be protected without inhibiting the swelling of lignocellulose, and the yield of monolignin alcohols can be increased.

[0048] Furthermore, in order to utilize lignocellulosic biomass without any waste, the inventors discovered a method for manufacturing sulfated cellulose nanofibers—a composite of lignin-derived substances, sulfated cellulose nanocrystals, and monolignin alcohols in parallel.

[0049] Therefore, the key points of the present invention are as follows.

[0050] (1) A composition comprising: cellulose nanofibers having sulfate groups and a substance derived from lignin.

[0051] (2) The composition according to (1), wherein the sulfate groups of the cellulose nanofibers having sulfate groups are represented by the chemical formula of (1),

[0052] [Chemical Formula 5]

[0053]

[0054] (In the formula, M represents a cation with a valence of 1 to 3).

[0055] (3) The composition according to (1) or (2), wherein the cellulose nanofibers having sulfate groups and the lignin-derived substance form a complex.

[0056] (4) The composition according to (3), wherein the composite is a composite of cellulose nanofibers having sulfate groups and a substance derived from lignin that has undergone hydrogen bonding.

[0057] (5) The composition according to (3), wherein the composite is a cross-linked composite of cellulose nanofibers having sulfate groups and a substance derived from lignin.

[0058] (6) The composition according to any one of (1) to (5) further comprises: at least one substance selected from resins and rubbers.

[0059] (7) The composition according to any one of (1) to (6) further comprises: at least one filler selected from organic fillers and inorganic fillers.

[0060] (8) A method of manufacturing the composition of (4) comprising: mixing cellulose nanofibers having sulfate groups with a lignin-derived substance while applying shear force.

[0061] (9) A method for manufacturing a material derived from lignocellulose, comprising:

[0062] (A). A step of preparing a mixture by mixing (a) lignin content of 20% or more relative to the total weight of lignocellulose, (b) sulfuric acid, (c) at least one compound selected from aldehyde, ketone, boric acid, 2-methoxypropylene, dimethyl carbonate and 2,2-dimethoxypropane, (d) dimethyl sulfoxide as a solvent, and (e) at least one carboxylic anhydride selected from acetic anhydride and propionic anhydride, and reacting it to obtain the reactant;

[0063] (B). The process of neutralizing the reactants obtained from step (A) with an alkali to obtain a neutralized product; and

[0064] (C). A process for separating the neutralized product obtained from process (B) into a first solid component and a first liquid component.

[0065] (10) The method according to (9), wherein, in step (A), the proportion of lignocellulose in the mixture is 5% to 50% by weight relative to the total weight of the mixture.

[0066] (11) According to the method of (9) or (10), wherein in step (A), (b), (c), (a) and (e) are added sequentially to (d) with a time difference.

[0067] (12) The method according to any one of (9) to (11), wherein in step (A), (b), (c), (a) and (e) are added to (d) in sequence, mixed for more than 30 minutes to allow it to react, and then (e) is added to allow it to react.

[0068] (13) The method according to any one of (9) to (12), wherein in step (A), after adding (b), (c) and (a) to (d) in sequence, the mixture is heated to above 50°C to allow it to react, then cooled to below 50°C, and after adding (e), it is allowed to react.

[0069] (14) The method according to any one of (9) to (13), wherein in step (A), after the solution of reactants in (d), (b), (c), (a) and (e) is partially diluted by 20 times to obtain a solution with an absorbance of 0.5 or more at a wavelength of 500 nm, step (B) is carried out.

[0070] (15) The method according to any one of (9) to (14) further comprises the following steps:

[0071] (D) The first solid component obtained from step (C) is composed of cellulose with sulfate groups and a substance derived from lignin, and the cellulose with sulfate groups and the substance derived from lignin form a cross-linked composite. This composite is mixed with water or an organic solvent or a mixture thereof while applying shear force and then defibriled to obtain a composite containing cellulose nanofibers with sulfate groups and a substance derived from lignin.

[0072] (16) The method according to any one of (9) to (15) further comprises the following steps:

[0073] (D'). The first solid component obtained from step (C) is composed of cellulose with sulfate groups and a substance derived from lignin, and the cellulose with sulfate groups and the substance derived from lignin form a cross-linked complex. This is then mixed with water or an organic solvent or a mixture thereof and sulfuric acid, and heated to obtain sulfated cellulose nanocrystals.

[0074] (17) The method according to any one of (9) to (16) further comprises the following steps:

[0075] (D”). The first solid component obtained from step (C) is mixed with a THF solvent to obtain a suspension, and the obtained suspension is separated into a second solid component and a second liquid component containing cellulose; and the uncrosslinked lignin-derived substances in the separated second liquid component are depolymerized to obtain monolignin alcohol.

[0076] (18) A composite comprising cellulose nanofibers having sulfate groups and a lignin-derived substance, wherein the cellulose nanofibers having sulfate groups interact with the lignin-derived substance.

[0077] (19) The composite according to (18) wherein the cellulose nanofibers having sulfate groups form hydrogen bonds with a substance derived from lignin.

[0078] (20) The composite according to (18) wherein the cellulose nanofibers having sulfate groups are cross-linked with a substance derived from lignin.

[0079] This specification contains the disclosure of Japanese Patent Application No. 2021-059316, which forms the basis of the priority of this application.

[0080] Invention Effects

[0081] According to the present invention, a composition comprising cellulose nanofibers and lignin or a composite thereof for the wasteless utilization of lignocellulosic biomass is provided, as well as a method for efficiently manufacturing materials derived from lignocellulosic biomass. Attached Figure Description

[0082] [ Figure 1 [This is a general scheme representing a method for producing materials derived from lignocellulosic biomass in parallel, based on existing technologies.]

[0083] [ Figure 2 [Illustration 1] is a diagram illustrating an example of an embodiment of the hydrogen-bonded complex of the present invention.

[0084] [ Figure 3 [Illustration 1] is a diagram illustrating an example of an embodiment of the hydrogen-bonded complex of the present invention.

[0085] [ Figure 4 [Illustration 1] is a diagram illustrating an example of an embodiment of the crosslinked composite of the present invention.

[0086] [ Figure 5 [Illustration 1] is a diagram illustrating an example of an embodiment of the composition of the present invention.

[0087] [ Figure 6 [Illustration 1] is an example of a method for manufacturing the hydrogen-bonded complex of the present invention.

[0088] [ Figure 7 [This is an example of a method for manufacturing a material derived from lignocellulose according to the present invention.]

[0089] [ Figure 8 [Illustration 1] represents an example of a parallel manufacturing method for materials derived from lignocellulose according to the present invention.

[0090] [ Figure 9 [Illustration 1] represents an example of a parallel manufacturing method for materials derived from lignocellulose according to the present invention.

[0091] [ Figure 10 [Illustration 1] is a diagram illustrating an example of the system of the present invention.

[0092] [ Figure 11 [Illustration 1] is a diagram illustrating an example of a control system of the system of the present invention. Detailed Implementation

[0093] Preferred embodiments of the present invention will now be described in detail.

[0094] In this specification, the features of the invention will be described with appropriate reference to the accompanying drawings. In the drawings, the dimensions and shapes of the parts are exaggerated for clarity and are not accurately depicted. Therefore, the scope of the invention is not limited to the dimensions and shapes of the parts shown in these drawings. It should be noted that the composition of the invention comprising cellulose nanofibers and lignin or a composite thereof, and the method for manufacturing materials derived from lignocellulose, are not limited to the embodiments described below. Various modifications and alterations that can be made by those skilled in the art can be implemented without departing from the spirit of the invention.

[0095] This invention relates to compositions comprising cellulose nanofibers having sulfate groups and substances derived from lignin.

[0096] Here, cellulose refers to a polysaccharide formed by the β-1,4-glycosidic linkage of glucose, represented by (C6H... 10 O5) n express.

[0097] Cellulose nanofibers are fibers composed of cellulose. The fiber width (fiber diameter (equivalent circle diameter)) is usually 1 nm to 500 nm, and the fiber length is usually 0.1 μm to 6 μm.

[0098] It should be noted that, in this specification and other documents, the range expressed by "numerical value ~ numerical value" refers to the range that includes that numerical value. For example, "1nm ~ 500nm" means "above 1nm and below 500nm", that is, the range from 1nm to 500nm that includes 1nm and 500nm.

[0099] There are no limitations on fiber width and fiber length. For example, an atomic force microscope (SPM-9700HT, manufactured by Shimadzu Corporation) can be used to measure the fiber width and fiber length of 50 randomly selected fibers, and the arithmetic mean can be calculated for measurement.

[0100] Cellulose nanofibers with sulfate groups, also known as sulfated cellulose nanofibers, are cellulose nanofibers formed by replacing at least one OH group in cellulose that constitutes cellulose nanofibers with a sulfate group. The sulfate group of cellulose nanofibers with sulfate groups is preferably a sulfate group as shown in the following formula (1) (where M represents a 1- to 3-valent cation).

[0101] [Chemical Formula 6]

[0102]

[0103] Examples of cations with a valence of 1 to 3, represented by M in formula (1), include hydrogen ions, metal ions, and ammonium ions. It should be noted that when M is a cation with a valence of 2 or 3, this cation forms ionic bonds with 2 or 3 -OSO3- ions.

[0104] Examples of metal ions include: alkali metal ions, alkaline earth metal ions, transition metal ions, and other metal ions.

[0105] Examples of alkali metals include lithium, sodium, potassium, rubidium, and cesium. Examples of alkaline earth metals include calcium and strontium. Examples of transition metals include iron, nickel, palladium, copper, and silver. Examples of other metals include beryllium, magnesium, zinc, and aluminum.

[0106] As an ammonium ion, not only NH4+ can be cited as an example. + NH4 can also be cited. + Ammonium ions derived from various amines are formed by replacing one or more hydrogen atoms with organic groups, such as NH4+. + Quaternary ammonium cations, alkanolamine ions, pyridinium ions, etc.

[0107] As the cation represented by M, hydrogen ions, sodium ions, potassium ions, calcium ions, or quaternary ammonium ions are preferred, considering the strength of their interaction with lignin and their processability. Any one of the cations listed above can be used, or a combination of two or more can be used.

[0108] Cellulose nanofibers having a sulfate ester group may also have other substituents besides the sulfate ester group. Here, when the cellulose nanofibers having a sulfate ester group have other substituents, these other substituents substitute for at least one of the OH groups in the cellulose constituting the cellulose nanofibers. Examples of other substituents are not limited, such as: anionic substituents and their salts, ester groups, ether groups, acyl groups, aldehyde groups, alkyl groups, alkylene groups, aryl groups, and combinations of two or more of these. When there are two or more combinations of other substituents, the proportion of each substituent is not limited. From the viewpoint of nanodispersibility, anionic substituents and their salts, or acyl groups, are preferred as other substituents. Carboxyl groups, phosphate ester groups, phosphite ester groups, and xanthate ester groups are particularly preferred as anionic substituents and their salts. When the anionic substituent is in the form of a salt, from the viewpoint of nanodispersibility, sodium salts, potassium salts, and calcium salts are particularly preferred. Furthermore, from the viewpoint of nanodispersibility, acetyl groups are particularly preferred as acyl groups.

[0109] The sulfation modification rate in cellulose nanofibers with sulfate groups can be set to any suitable value depending on the application. The sulfation modification rate of cellulose nanofibers with sulfate groups can be expressed as the sulfur content (wt%) in the cellulose nanofibers. The sulfur content (wt%) in the sulfation-modified cellulose nanofibers is not limited, but is typically 0.05 wt% to 30 wt%, preferably 0.1 wt% to 25 wt%, and more preferably 0.5 wt% to 22 wt%. When the sulfur content is higher than 30 wt%, there is a risk of reduced crystallinity and heat resistance. When the sulfur content is less than 0.05 wt%, there is a risk that the interaction between the sulfate groups in the cellulose nanofibers and substances derived from lignin cannot be fully obtained.

[0110] The sulfur content (wt%) in cellulose nanofibers can be determined, for example, by combustion absorption-ion chromatography (IC). Alternatively, the sulfur content (wt%) in cellulose nanofibers can also be confirmed by infrared spectroscopy (IR). The sulfur content of cellulose nanofibers with sulfate groups can be determined, for example, by the following methods.

[0111] • Measurement method: Combustion absorption-IC

[0112] • Measuring apparatus: ICS-1500 manufactured by Dionex Corporation, Japan

[0113] • Determination conditions: The sample was weighed on a magnetic plate and burned in an oxygen atmosphere (flow rate: 1.5 L / min) in a ring furnace (1350 °C). The generated gaseous components were absorbed by 3% hydrogen peroxide water (20 ml) to obtain an absorbent. The absorbent was diluted to 100 ml with pure water, and the diluted solution was used for ion chromatography. The sulfate ion concentration relative to the cellulose nanofibers was calculated from the determination results. Furthermore, the sulfur content was calculated from the sulfate ion concentration using the following formula. It should be noted that the detection limit of the cellulose-based sulfate ion concentration based on this method is 0.01 wt%. Therefore, the lower limit of quantification of the sulfur content calculated from the sulfate ion concentration is 0.01 wt%. Therefore, cellulose nanofibers with sulfate groups and a sulfur content of less than 0.01 wt% can be unmodified (i.e., not sulfated) cellulose nanofibers.

[0114] • Sulfur content (wt%) = Sulfate ion concentration × 32 / 96

[0115] The average fiber diameter of the cellulose nanofibers with sulfate groups of the present invention is the same as that of the defined cellulose nanofibers, typically ranging from 1 nm to 500 nm. The average fiber diameter of the cellulose nanofibers is preferably 2 nm to 100 nm, more preferably 3 nm to 50 nm, and even more preferably 5 nm to 20 nm. When the average fiber diameter is less than 1 nm, there is a risk of reduced performance in terms of the nanofibers' strength and other properties. When the average fiber diameter exceeds 500 nm, the fiber diameter is large, and therefore there is a tendency to make it difficult to exert the performance characteristics of nanofibers. It should be noted that the average fiber diameter is obtained by arithmetically averaging 50 randomly selected fibers from an atomic force microscope image, similar to the cellulose nanofibers described above.

[0116] The crystallinity of the sulfate-based cellulose nanofibers of the present invention may depend on the cellulose raw material used. For example, cotton cellulose may have a higher crystallinity than wood cellulose. That is, the crystallinity of the cellulose nanofibers varies depending on the cellulose raw material used. However, in order to influence the properties of cellulose nanofibers such as homogenization with lignin-derived substances, processability, heat resistance, and reinforcing effect, the crystallinity of cellulose nanofibers is typically 20% to 99%, preferably 30% to 95%, more preferably 40% to 90%, and even more preferably 50% to 85%. When the crystallinity is below 20%, there is a risk of reduced heat resistance and stiffness of the cellulose nanofibers. On the other hand, when it exceeds 99%, homogenization with lignin-derived substances becomes difficult.

[0117] Lignin is a network polymer compound formed by the condensation of structural units with phenylpropane as the backbone. It is the unmodified composition extracted from natural biomass. In addition, lignin has a structure in which aromatic core units, guaiacyl (G core), syringyl (S core), and p-hydroxyphenyl (H core or P core), are bonded together in proportions specific to each type of biomass.

[0118] Lignin-derived substances refer to compounds extracted from natural biomass by any method, with some of the substituents within the molecule being modified. Furthermore, compounds derived from lignin-derived substances extracted from biomass and further modified by any method by substituting some of the substituents within the molecule are also classified as lignin-derived substances. Examples of lignin-derived substances include: kraft lignin, lignin sulfonic acid, soda lignin, soda anthraquinone lignin, sulfated lignin, diol lignin, enzymatically hydrolyzed lignin, hydrothermally treated lignin, steam-explosion treated lignin, organosolv lignin, and their salts.

[0119] There is no limitation on the weight-average molecular weight of lignin, which is usually 1,500 to 500,000, preferably 10,000 to 200,000. When the weight-average molecular weight of lignin is below 1,500, the composition is prone to becoming brittle, and when it exceeds 500,000, it is difficult to achieve uniform dispersion when mixed with cellulose.

[0120] The compositions of the present invention typically contain cellulose nanofibers with sulfate groups in an amount of 0.03% to 85% by weight, preferably 5% to 50% by weight, relative to the total weight of the composition.

[0121] The compositions of the present invention typically contain lignin-derived substances in an amount of 0.03% to 85% by weight, preferably 5% to 50% by weight, relative to the total weight of the composition.

[0122] In the compositions of the present invention, the weight ratio of cellulose nanofibers with sulfate groups to lignin-derived substances (cellulose nanofibers with sulfate groups: lignin-derived substances) is typically 0.05:99.5 to 85.0:15.0, preferably 5.0:95.0 to 50.0:50.0.

[0123] The composition of the present invention, by comprising cellulose nanofibers having sulfate groups and a lignin-derived substance, enables a strong interaction between the sulfate groups of the sulfated cellulose nanofibers and the OH groups of the lignin-derived substance due to the smaller acid dissociation constant of the sulfate groups compared to OH, COOH, and phosphate groups. Furthermore, this improves the compatibility between sulfated cellulose and lignin. Therefore, the composition of the present invention, by comprising cellulose nanofibers having sulfate groups and a lignin-derived substance in the stated amounts, enables a strong interaction between the SO4 groups contained in the sulfated cellulose nanofibers and the OH groups contained in the lignin-derived substance, thereby further improving moldability when using this composition for molding.

[0124] It should be noted that the present invention utilizes the strong interaction (hydrogen bond) between the SO4 group contained in the cellulose nanofibers with sulfate groups and the OH group contained in the lignin-derived substance. Therefore, the compositions of the present invention also include combinations or compositions that result in a combination of cellulose nanofibers with sulfate groups and a lignin-derived substance, such as combinations or compositions that contain cellulose nanofibers with sulfate groups and a lignin-derived substance in solid form, for example, when added to and used in a solvent.

[0125] The present invention also relates to a composite of cellulose nanofibers having sulfate groups and a lignin-derived substance (a composite of sulfated cellulose nanofibers and a lignin-derived substance) and a composition comprising the composite.

[0126] A composite of cellulose nanofibers with sulfate groups and lignin-derived substances refers to a composite consisting of cellulose nanofibers with sulfate groups and lignin-derived substances, wherein the cellulose nanofibers with sulfate groups and the lignin-derived substances interact with each other.

[0127] In the composite of the present invention, examples of interactions between the materials include hydrogen bonding, ionic bonding, covalent bonding, and dipole interaction.

[0128] For example, as a composite in this invention, one can cite a composite formed by hydrogen bonding of cellulose nanofibers with sulfate ester groups and a substance derived from lignin (also known as a "hydrogen-bonded composite").

[0129] Hydrogen bonding refers to the attractive interaction between the S and / or O groups of SO4 contained in cellulose nanofibers with sulfate groups and the H groups of OH contained in lignin-derived substances.

[0130] In the hydrogen-bonded complex of the present invention, the weight ratio of cellulose nanofibers with sulfate groups to lignin-derived substances (cellulose nanofibers with sulfate groups: lignin-derived substances) is typically 0.05:99.5 to 85.0:15.0, preferably 5.0:95.0 to 50.0:50.0.

[0131] By setting the weight ratio of each material in the hydrogen-bonded complex of the present invention to the range described above, stronger hydrogen bonds are formed between the SO4 groups contained in the cellulose nanofibers with sulfate ester groups and the OH groups contained in the lignin-derived material, thereby further improving the moldability when using the composition for molding.

[0132] For example, as a composite in this invention, a cross-linked composite (also called a "cross-linked composite") can be formed by cellulose nanofibers having sulfate groups and a lignin-derived substance.

[0133] Crosslinking refers to the formation of chemical bonds through condensation or addition reactions between the hydroxyl groups of cellulose and the hydroxyl, aldehyde, carboxyl, methoxy, carbonyl, olefin, or ether sites of substances derived from lignin.

[0134] As for the type of chemical bond, there are no restrictions as long as it can form a bond; a bond can be formed through one or more cross-linking agents.

[0135] There is no limitation on the type of bond; for example, urethane bonds, ester bonds, ether bonds, amide bonds, urea bonds, etc.

[0136] In the crosslinked composite of the present invention, the weight ratio of cellulose nanofibers with sulfate groups to lignin-derived substances (cellulose nanofibers with sulfate groups: lignin-derived substances) is typically 0.05:99.5 to 85.0:15.0, preferably 5.0:95.0 to 50.0:50.0.

[0137] By setting the weight ratio of each material in the crosslinked composite of the present invention to the range described above, the bonding between the materials becomes stronger, in addition to the strong interaction (hydrogen bond) formed between the SO4 groups contained in the cellulose nanofibers with sulfate groups and the OH groups contained in the lignin-derived material, and the moldability can be further improved when the composition is used for molding.

[0138] The weight-average molecular weight of the cross-linked composite is not limited, but is typically 1,000 to 200,000, preferably 10,000 to 100,000. If the weight-average molecular weight of the cross-linked composite is less than 1,000, the composite is prone to becoming brittle; if it exceeds 200,000, the cross-linking is excessive, resulting in a strong composite with reduced processability.

[0139] In cross-linked complexes, the formation of cross-links is not particularly limited and can be confirmed by identifying bonds derived from the cross-linking structure, physical constants derived from cross-linking, and changes in physical properties through methods such as infrared spectroscopy, near-infrared spectroscopy, Raman spectroscopy, NMR, elemental analysis, GPC, and DSC.

[0140] In addition to containing cellulose nanofibers having sulfate groups and substances derived from lignin or complexes thereof, the compositions of the present invention may also contain additives.

[0141] As an additive, there are no limitations, but examples include: at least one substance selected from resins and rubbers, at least one filler selected from organic fillers and inorganic fillers, etc.

[0142] As for resins and rubbers, there are no limitations. Examples include: phenolic resins, melamine resins, urea-formaldehyde resins, alkyd resins, epoxy resins, unsaturated polyester resins, polyurethane resins, polyethylene resins (high-density polyethylene, medium-density polyethylene, low-density polyethylene, etc.), polypropylene resins, polystyrene resins, acrylic resins, polyvinyl alcohol, acrylamide resins, polysiloxane resins, natural rubber, synthetic rubber, etc.

[0143] As an organic filler, there are no limitations. For example, in addition to substances that form the resin and rubber into granules, other examples include functional compounds such as pigments, UV absorbers, antioxidants, antistatic agents, and surfactants formed from organic matter.

[0144] As inorganic fillers, there are no limitations; examples include: silica, mica, talc, clay, carbon, carbonates such as calcium carbonate and magnesium carbonate, oxides such as alumina, titanium oxide, zinc oxide, iron oxide, ceramics such as ferrite, etc.

[0145] The compositions of the present invention typically contain additives in an amount of 0.1% to 10.0% by weight, preferably 0.5% to 5.0% by weight, relative to the total weight of the composition.

[0146] The compositions of the present invention, by including inorganic fillers and organic fillers formed from resins and rubber into granules as additives, can improve the moldability, particularly the tensile strength, when molding the compositions of the present invention. Furthermore, when the organic filler is a functional compound, the characteristic properties of various functional compounds can be achieved simultaneously with tensile strength and flexural strength.

[0147] Figures 2-5 Examples illustrating embodiments of the present invention. Figure 2 A represents an example of a complex (hydrogen-bonded complex) formed by hydrogen bonding of cellulose nanofibers with sulfate groups and a substance derived from lignin. Figure 2 B represents an example of a complex (hydrogen-bonded complex) consisting of cellulose nanofibers with sulfate and carboxyl groups and a substance derived from lignin that has undergone hydrogen bonding. Figure 2 C represents an example of a complex (hydrogen-bonded complex) consisting of cellulose nanofibers with sulfate and phosphate groups and substances derived from lignin that have undergone hydrogen bonding. Figure 3 D represents an example of a complex (hydrogen-bonded complex) consisting of cellulose nanofibers with sulfate and acetyl groups and substances derived from lignin that have undergone hydrogen bonding. Figure 3 E represents an example of a hydrogen-bonded complex (hydrogen-bonded complex) consisting of cellulose nanofibers with sulfate, phosphate, and acetyl groups, as well as lignin-derived substances, that are hydrogen-bonded together. Figure 2 A~C and Figure 3In the composites D through E, a strong electrostatic interaction occurs between the sulfate groups of the cellulose nanofibers with sulfate groups and the OH groups of the lignin-derived material, resulting in increased strength as a composite. Furthermore, the composite also exhibits flexibility. Figure 4 F represents an example of a cross-linked complex (cross-linked complex) formed by cellulose nanofibers with sulfate groups and lignin-derived substances. Figure 4 In the F composite, in addition to the strong electrostatic interaction between the sulfate groups of the cellulose nanofibers with sulfate groups and the OH groups of the lignin-derived substances, the strength of the composite is further enhanced by cross-linking. On the other hand, the composite also possesses flexibility. Figure 5 G represents an example of a composition comprising cellulose nanofibers with sulfate groups and a lignin-derived substance, as well as a resin. Figure 5 H represents an example of a composition comprising cellulose nanofibers with sulfate groups and lignin-derived substances, as well as inorganic and organic fillers. Figure 5 I represents an example of a composition comprising cellulose nanofibers with sulfate groups and a lignin-derived substance, a resin, and inorganic and organic fillers.

[0148] The composite of the present invention can be molded and processed, and can be used for various shell and container applications. Furthermore, since it can be molded into a sheet shape, it can be used alone or in combination with paper or the like for encapsulation purposes.

[0149] The present invention also relates to a composite of cellulose nanofibers having sulfate groups and a lignin-derived substance, a composition comprising cellulose nanofibers having sulfate groups and a lignin-derived substance or a composite thereof, or a method for manufacturing a material derived from lignocellulose.

[0150] As one embodiment of the present invention, a method for manufacturing the composition of the present invention comprises: mixing cellulose nanofibers having sulfate groups with a substance derived from lignin, preferably mixing while applying shear force. At this time, additives may also be added as needed.

[0151] The aforementioned cellulose nanofibers can be used as cellulose nanofibers having sulfate groups. For example, the cellulose nanofibers having sulfate groups described in Patent Document 2 can be used as cellulose nanofibers having sulfate groups.

[0152] The aforementioned substance can be used as a lignin-derived substance. Examples of lignin-derived substances include Indulin AT (manufactured by Sigma-Aldrich), alkaline lignin (manufactured by Sigma-Aldrich), lignin sulfonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), and diol lignin (manufactured by LIGNOMATE RIA Co., Ltd.).

[0153] In this invention, for example, cellulose nanofibers having sulfate groups and lignin-derived substances are added, in a manner preferably in proportion to the materials in the composition, to a container containing a solvent, such as water, dimethyl sulfoxide, dimethylformamide, ethylene glycol, diethyl ether, dioxane, tetrahydrofuran, methyltetrahydrofuran, etc., and then mixed using a device capable of applying shear force to the materials, such as a mixer, three-roll mill, twin-screw mixer, three-screw planetary mixer, disperser, paint mixer, bead mill, shredder, planetary mixer, etc.

[0154] There are no restrictions on the mixing conditions; conditions known to those skilled in the art can be used, such as mixing at a temperature typically between 20°C and 150°C for 5 minutes to 1 hour.

[0155] The manufacturing method of the present invention can be used to manufacture the composites or compositions of the present invention, namely, cellulose nanofibers having sulfate groups and lignin-derived substances or composites thereof, particularly composites of cellulose nanofibers having sulfate groups and lignin-derived substances hydrogen-bonded or compositions containing such composites.

[0156] Figure 6 This is an example of a method for manufacturing a hydrogen-bonded complex according to the embodiments of the present invention. Figure 6 In this study, sulfated cellulose nanofibers were prepared from commercially available pulp. The prepared sulfated cellulose nanofibers were then mixed with commercially available lignin derivatives under shear force to prepare a composite of sulfated cellulose nanofibers and lignin derivatives.

[0157] As one embodiment of the present invention, the method for manufacturing the lignocellulose-derived material of the present invention includes:

[0158] (A). A step of preparing a mixture by mixing (a) lignin content of 20% or more relative to the total weight of lignocellulose, (b) sulfuric acid, (c) at least one compound selected from aldehyde, ketone, boric acid, 2-methoxypropylene, dimethyl carbonate and 2,2-dimethoxypropane, (d) dimethyl sulfoxide as a solvent, and (e) at least one carboxylic anhydride selected from acetic anhydride and propionic anhydride, and reacting it to obtain the reactant;

[0159] (B). The process of neutralizing the reactants obtained from step (A) with an alkali to obtain a neutralized product; and

[0160] (C). A process of separating the neutralized product obtained from step (B) into a first solid component and a first liquid component.

[0161] First, in step (A), a mixture is prepared by mixing (a) lignin content of 20% or more relative to the total weight of lignin cellulose, (b) sulfuric acid, (c) at least one compound selected from aldehydes, ketones, boric acid, 2-methoxypropylene, dimethyl carbonate and 2,2-dimethoxypropane, (d) dimethyl sulfoxide as a solvent, and (e) at least one carboxylic anhydride selected from acetic anhydride and propionic anhydride, and the mixture is reacted to protect the OH groups of the lignin-derived substance, and the cellulose nanofibers are sulfated, and the cellulose nanofibers with sulfate groups are crosslinked with the lignin-derived substance.

[0162] In process (A), the lignocellulose in step (a) is lignocellulose with a lignin content of 20% or more relative to the total weight of lignocellulose. In the lignocellulose of step (a), the lignin content is preferably 20% or more relative to the total weight of lignocellulose, and particularly preferably 30% or more. The lignocellulose in step (a) can be, for example, wood chips with the bark removed, including lignocellulose that is marketed as gardening materials such as pine chips, cedar chips, cypress chips, and birch chips, or it can be obtained as scrap material. Furthermore, nut shells and the like can be obtained as waste from food processing plants.

[0163] The proportion of lignocellulose in the mixture of (a), (b), (c), (d) and (e) in process (A) is not limited, but is typically 5% to 50% by weight, preferably 15% to 30% by weight, relative to the total weight of the mixture of (a), (b), (c), (d) and (e).

[0164] By setting the lignin content of the lignocellulose in step (a) of process (A) and the content in the mixture to the range described, it is possible not only to efficiently recover the complex of cellulose nanofibers with sulfate groups and lignin-derived substances, but also to efficiently recover and utilize high-value monolignin alcohols.

[0165] The compound in step (b) of process (A) is sulfuric acid.

[0166] The proportion of sulfuric acid in (b) of the mixture in steps (a), (b), (c), (d) and (e) of process (A) is not limited, but is typically 0.5% to 3.0% by weight relative to the total weight of the mixture in steps (a), (b), (c), (d) and (e).

[0167] By ensuring that the sulfuric acid content in the mixture during step (b) of process (A) is within the specified range, cellulose sulfation can be carried out efficiently.

[0168] The compound in step (c) of step (A) is at least one compound selected from aldehydes, ketones, boric acid, 2-methoxypropene, dimethyl carbonate and 2,2-dimethoxypropane.

[0169] Among the compounds in (c), there is no limitation on what constitutes an aldehyde, and examples include: formaldehyde, propionaldehyde, benzaldehyde, acetaldehyde, butyraldehyde, pentanaldehyde, etc.

[0170] (c) Among the compounds, there is no limitation on what constitutes a ketone, and examples include acetone, methyl ethyl ketone, etc.

[0171] (c) Among the compounds, there is no limitation on the boric acid, and examples include: phenylboronic acid, methylboronic acid, 2-thiopheneboronic acid, etc.

[0172] The proportion of compound (c) in the mixture of (a), (b), (c), (d) and (e) in process (A) is not limited, but is typically 0.5% to 10.0% by weight relative to the total weight of the mixture of (a), (b), (c), (d) and (e).

[0173] By ensuring that the types of compounds in step (c) of process (A) and their contents in the mixture are within the specified range, the OH groups of substances derived from lignin can be effectively protected.

[0174] The solvent in step (d) of process (A) is dimethyl sulfoxide (DMSO).

[0175] The proportion of solvent in (d) of the mixture in steps (a), (b), (c), (d) and (e) of process (A) is not limited, but is typically 40.0% to 85.0% by weight relative to the total weight of the mixture in steps (a), (b), (c), (d) and (e).

[0176] By ensuring that the type of solvent and the content of the mixture in step (d) of process (A) are within the specified range, the solvent can efficiently swell lignocellulose and improve the extraction efficiency of lignin components.

[0177] In step (A), the carboxylic anhydride in step (e) is at least one carboxylic anhydride selected from acetic anhydride and propionic anhydride. In addition to neopentanoic anhydride and benzoic anhydride, it may further include TFA, oxalyl chloride, and halogen.

[0178] The proportion of carboxylic anhydride in the mixture of (a), (b), (c), (d) and (e) in process (A) is not limited, but is typically 3.0% to 15.0% by weight relative to the total weight of the mixture of (a), (b), (c), (d) and (e).

[0179] By ensuring that the types of compounds in step (e) and their contents in the mixture are within the specified range, the OH groups of substances derived from lignin can be effectively protected.

[0180] The mixing and reaction conditions for (a), (b), (c), (d), and (e) in step (A) are not limited. For example, in step (A), (a), (b), (c), (d), and (e) are mixed at a temperature of 50°C to 120°C for a period of 0.5 to 5.0 hours to allow them to react.

[0181] In step (A), it is preferable to add (b), (c), (a) and (e) to (d) in a time difference in the order they are recorded.

[0182] Here, "adding materials with a time difference" means that after adding one material, there is usually a 1-60 minute break, preferably a 5-30 minute break, before adding the next material.

[0183] In step (A), by sequentially adding (b), (c), (a), and (e) to step (d) with a time difference, the formability, particularly the bending resistance, of the obtained lignocellulose-derived material, especially the composition of cellulose nanofibers with sulfate groups and lignin-derived substances, and the cross-linked composites formed by the sulfate-group cellulose nanofibers and lignin-derived substances, or compositions containing such composites, can be improved during molding. Furthermore, the protection reaction of the β-O-4 bonds in the lignin-derived substances proceeds efficiently, thus increasing the yield of lignin monomers.

[0184] In step (A), it is preferable to add (b), (c), (a) and (e) sequentially to (d), usually mixing for more than 30 minutes, preferably more than 60 minutes, usually mixing for less than 120 minutes, preferably less than 90 minutes, to allow the reaction to proceed. Then, (e) is added to allow the reaction to proceed, preferably mixing further, usually mixing for 30 to 120 minutes, to allow the reaction to proceed.

[0185] In step (A), (b), (c), (a), and (e) are added sequentially to (d). After a certain period of time, (e) is added again to allow the reaction to proceed. This effectively sulfates the hydroxyl groups of cellulose, improving the formability, particularly the bending resistance, of the resulting lignocellulose-derived material, especially that composed of cellulose nanofibers with sulfate groups and lignin-derived substances. Furthermore, the lignin-derived cellulose nanofibers forming cross-linked composites with the lignin-derived substances, or compositions containing such composites, exhibit improved formability during molding. In addition, the protection reaction of the β-O-4 bonds in the lignin-derived substances also proceeds efficiently, thus increasing the yield of lignin monomers.

[0186] In step (A), it is preferable to add (b), (c) and (a) to (d) at a temperature of 25°C to 50°C, and then heat to a temperature of 50°C or higher, preferably 60°C or higher and usually below 120°C, preferably below 100°C, while mixing for 30 to 120 minutes to allow the reaction to proceed. Then, cool to a temperature of 50°C or lower, preferably below 40°C, usually above 20°C, add (e), and allow the reaction to proceed. It is preferable to mix further, usually mixing for 30 to 120 minutes to allow the reaction to proceed.

[0187] In step (A), after adding (b), (c), and (a) to (d), the mixture is heated to a certain temperature and allowed to react. Then, it is cooled to a certain temperature, and (e) is added to allow it to react. This effectively sulfates the hydroxyl groups of cellulose, improving the formability, particularly the bending resistance, of the resulting lignocellulose-derived material, especially composed of cellulose nanofibers with sulfate groups and lignin-derived substances. Furthermore, the protection reaction of the β-O-4 bonds in the lignin-derived substances also proceeds efficiently, thus increasing the yield of lignin monomers.

[0188] The determination of the completion of step (A), i.e., the determination of proceeding from step (A) to step (B), can be made by means of reaction time, for example, based on the absorbance value of the solution portion of the reactants. For example, step (A) can be completed based on the absorbance of the solution obtained by diluting the solution portion of reactants (d), (b), (c), (a), and (e) by 20 times at a wavelength of 500 nm, i.e., stopping mixing and / or the reaction. Specifically, in the implementation of step (A), a portion of the solution of reactants (d), (b), (c), (a), and (e) can be sampled, and the absorbance of the solution obtained by diluting by 20 times at a wavelength of 500 nm can be measured. After the absorbance is typically 0.4 or higher, preferably 0.5 or higher, and more preferably 0.7 or higher, mixing and / or the reaction can be stopped, and step (B) can proceed.

[0189] In step (A), the efficiency of generating high-value monolignin alcohols can be improved by determining the absorbance of the solution obtained by diluting the solution in the reactants by 20 times.

[0190] In step (A), DMSO and acetic anhydride or propionic anhydride convert the OH groups of the lignin-derived substance into aldehyde groups via an Albright-Goldman oxidation reaction as shown in (Reaction Formula 1). Therefore, even if the compound (c) introduced at the start of the reaction, particularly the aldehyde, is consumed, the chemical equilibrium of the protective reaction of the OH groups of the lignin-derived substance is maintained in the direction of advancing the acetal reaction by replenishing the aldehyde generated from Reaction Formula 1. Furthermore, the aldehyde group (CHO group) of the lignin-derived substance generated in Reaction Formula 1 undergoes an acetal reaction with the adjacent OH group of the lignin-derived substance. As a result, according to the present invention, it is possible to simultaneously achieve the swelling of lignocellulose required to increase the yield of monolignin alcohol and the direction of the acetal reaction advancing the chemical equilibrium.

[0191] [Chemical Formula 7]

[0192] (Reaction 1)

[0193]

[0194] (In the formula, R represents lignin residues.)

[0195] Therefore, in step (A) of the present invention, by mixing the raw materials of (a) to (e), the OH groups of the lignin-derived substance can be protected, the cellulose nanofibers can be sulfated, and the cellulose nanofibers with sulfate groups can be crosslinked with the lignin-derived substance.

[0196] Next, in step (B), the reactants obtained from step (A) are neutralized using alkali.

[0197] There are no limitations on what constitutes an alkali; examples include sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, and ammonia.

[0198] Neutralization is carried out to bring the pH of the solution portion of the reactants to a level typically of 5.0 to 8.0, preferably 6.5 to 7.5.

[0199] By neutralizing in step (B), compositions containing cellulose nanofibers with sulfate groups and lignin-derived substances or their complexes can significantly suppress changes in physical properties during long-term storage.

[0200] Furthermore, in step (C), the neutralized product obtained from step (B) is separated into a first solid component and a first liquid component. Here, the first solid component comprises cellulose having sulfate groups and a lignin-derived substance, wherein the cellulose having sulfate groups and the lignin-derived substance form a cross-linked complex. The first liquid component comprises uncross-linked lignin-derived substance, a hemicellulose component, and a dimethyl sulfoxide solvent.

[0201] There is no limitation to the method for separating the neutralized product into a first solid component and a first liquid component. Examples of separation techniques known in the art include filter filtration, pressure filtration, vacuum filtration, centrifugation, spiral filtration, and press filtration. The solid-liquid separation in step (C) can be adjusted to any liquid content. Therefore, the product obtained in step (C) consists of cellulose with sulfate groups and lignin-derived substances, and the cross-linked complex formed by the cellulose with sulfate groups and the lignin-derived substances can contain uncross-linked lignin-derived substances.

[0202] By adjusting the liquid content during solid-liquid separation, the stoichiometric ratio of cellulose with sulfate groups to lignin-derived substances can be controlled. This can improve the formability, particularly the breaking strength and flexural strength, of the resulting cellulose-derived materials, especially those composed of cellulose nanofibers with sulfate groups and lignin-derived substances, and the cross-linked composites formed by the cellulose nanofibers with sulfate groups and lignin-derived substances or compositions containing such composites.

[0203] In step (C), a first solid component consisting of cellulose with sulfate groups and a lignin-derived substance, where the cellulose with sulfate groups and the lignin-derived substance form a cross-linked complex, is separated from the first liquid component consisting of an uncross-linked lignin-derived substance, a hemicellulose component, and a dimethyl sulfoxide solvent. Thus, in steps (D), (D'), (D”), and (D″′) described in detail below, cellulose nanofibers with sulfate groups and a lignin-derived substance, a cross-linked complex formed by the cellulose nanofibers with sulfate groups and the lignin-derived substance, sulfated cellulose nanocrystals, cellulose, and monolignin alcohol can be obtained in parallel.

[0204] As one embodiment of the present invention, the method for manufacturing the lignocellulose-derived material of the present invention further includes the following steps:

[0205] (D) The first solid component obtained from step (C) is composed of cellulose with sulfate groups and a lignin-derived substance, and the cellulose with sulfate groups and the lignin-derived substance form a cross-linked composite. This is mixed with water or an organic solvent or a mixture thereof while applying shear force, so that the negatively charged sulfate groups in the cellulose with sulfate groups electrostatically repel each other. The fiber width is then defiberized to the nanoscale to obtain a composite containing cellulose nanofibers with sulfate groups and a lignin-derived substance, particularly composed of cellulose nanofibers with sulfate groups and a lignin-derived substance, and the cellulose nanofibers with sulfate groups and the lignin-derived substance form a cross-linked composite.

[0206] The mixing conditions are not limited, but are usually between 5°C and 40°C. The mixture consists of cellulose with sulfate groups and a substance derived from lignin, and the cellulose with sulfate groups and the substance derived from lignin form a cross-linked complex. The mixture is then mixed with water or an organic solvent or a mixture thereof for 0.1 hours to 2 hours.

[0207] In step (D), for example, a composite obtained from step (C) consisting of cellulose with sulfate groups and a lignin-derived substance, wherein the cellulose with sulfate groups and the lignin-derived substance are cross-linked, is added to a container containing water as a solvent in a manner typically 0.1% to 10% by weight relative to the total weight of the mixture. The mixture is then mixed using an apparatus capable of applying shear force to the composite consisting of cellulose with sulfate groups and the lignin-derived substance, such as a mixer, three-roll mill, twin-screw mixer, three-screw planetary mixer, disperser, paint mixer, bead mill, shredder, planetary mixer, etc., to obtain a dispersion of a composite consisting of cellulose nanofibers with sulfate groups and a lignin-derived substance, wherein the cellulose nanofibers with sulfate groups and the lignin-derived substance are cross-linked, which is a material derived from lignocellulose. Furthermore, by drying the dispersion using known methods such as freeze-drying or spray-drying as needed, a solid component can be obtained, consisting of cellulose nanofibers with sulfate groups and lignin-derived substances, and a cross-linked composite formed between the cellulose nanofibers with sulfate groups and the lignin-derived substances.

[0208] Figure 7 This illustrates an example of a method (A) to (D) for manufacturing a material derived from lignocellulose according to the embodiments of the present invention. Figure 7 In step (A), dried lignocellulose biomass (a) and materials (b) to (e) are preferably mixed in the order of (d), (b), (c), (a), and (e), while simultaneously protecting the OH groups of the lignin-derived substances in the biomass and sulfation of the cellulose. Then, after a neutralization step (B) and a separation step (C), a dispersion of a composite of sulfation-derived cellulose nanofibers and lignin-derived substances is prepared by mixing and defibrating while applying shear force in step (D). Furthermore, the dispersion is dried using known methods such as freeze-drying or spray drying as needed, thereby obtaining a solid component composed of cellulose nanofibers with sulfation groups and lignin-derived substances, wherein the cellulose nanofibers with sulfation groups and the lignin-derived substances form a cross-linked composite.

[0209] As one embodiment of the present invention, the method for manufacturing the lignocellulose-derived material of the present invention may further include the following steps:

[0210] (D'). The first solid component obtained from step (C) is composed of cellulose with sulfate groups and a substance derived from lignin, and the cellulose with sulfate groups and the substance derived from lignin form a cross-linked complex. This is mixed with water or an organic solvent or a mixture thereof and sulfuric acid, and then heated to obtain sulfated cellulose nanocrystals.

[0211] In step (D'), for example, a mixture is prepared by mixing the first solid component obtained from step (C) which consists of cellulose with sulfate groups and a substance derived from lignin, and the cellulose with sulfate groups and the substance derived from lignin form a cross-linked complex (typically 2% to 20% by weight relative to the total weight of the mixture), water (typically 20% to 50% by weight relative to the total weight of the mixture), and sulfuric acid (typically 40% to 70% by weight relative to the total weight of the mixture). The mixture is then stirred for 20 minutes to 3 hours under conditions typically heated to 40°C to 90°C, thereby obtaining sulfated cellulose nanocrystals as a material derived from lignocellulose.

[0212] By performing step (D') after step (A) and then step (C), the acid hydrolysis reaction time in step (D') can be shortened.

[0213] As one embodiment of the present invention, the method for manufacturing the lignocellulose-derived material of the present invention may further include the following steps:

[0214] (D”). The first solid component obtained from step (C), particularly the first solid component containing uncrosslinked lignin-derived substances, is mixed with a THF solvent to obtain a suspension. The obtained suspension is separated into a second solid component containing cellulose and a second liquid component. The uncrosslinked lignin-derived substances in the separated second liquid component are depolymerized to obtain monolignin alcohol.

[0215] There is no limitation on the method for separating suspended matter into a second solid component and a second liquid component. Examples of separation techniques known in the art include filter filtration, pressure filtration, depressurization filtration, centrifugal separation, spiral filtration, and press filtration.

[0216] In step (D”), cellulose as a second solid component can be obtained from the suspension obtained by mixing the first solid component with THF solvent, and an uncrosslinked lignin-derived substance as a second liquid component can be obtained. Monolignin alcohol is obtained from the uncrosslinked lignin-derived substance using a depolymerization treatment known in the art. Therefore, cellulose and monolignin alcohol can be obtained in parallel.

[0217] As one embodiment of the present invention, the method for manufacturing the lignocellulose-derived material of the present invention may further include the following steps:

[0218] (D″′). The first liquid component obtained from step (C), which contains substances derived from lignin, hemicellulose, and dimethyl sulfoxide, is precipitated by adding an ether solvent such as diethyl ether. The hemicellulose component and dimethyl sulfoxide are removed as liquid components by separation techniques such as filtration. The separated substances derived from lignin are depolymerized to obtain monolignin alcohol.

[0219] In step (D″′), by using a depolymerization treatment known in the art, i.e., adding an ether solvent such as diethyl ether to the first liquid component obtained from step (C) to precipitate the lignin-derived substances, removing the hemicellulose component and dimethyl sulfoxide as liquid components by separation techniques such as filtration, and depolymerizing the separated lignin-derived substances, monolignin alcohol can be obtained.

[0220] In steps (D”) and (D″′), for example, a mixture is prepared by mixing a lignin-derived substance obtained through step (C) and separation treatment (typically 0.5% to 20% by weight relative to the total weight of the mixture), tetrahydrofuran (typically 80% to 99% by weight relative to the total weight of the mixture), hydrogen (introduced at a pressure of 0.8 MPa to 5 MPa, under closed conditions), and a metal catalyst such as ruthenium carbon, palladium carbon, platinum carbon, etc. The mixture is stirred for 1 hour to 6 hours under conditions typically heated to 100°C to 250°C, thereby obtaining a monolignin alcohol as a material derived from lignocellulose.

[0221] The manufacturing method of the present invention enables the parallel and efficient production of materials derived from lignocellulose, particularly those composed of cellulose nanofibers with sulfate groups and lignin-derived substances, wherein the cellulose nanofibers with sulfate groups and the lignin-derived substances form cross-linked composites, compositions comprising the composites, sulfated cellulose nanocrystals, cellulose, and monolignin alcohols.

[0222] Figure 8 and 9 The diagram shows an example of a method for manufacturing a crosslinked composite according to an embodiment of the present invention, from (A) to (D′″). Figure 8In step (A), the dried lignocellulose biomass (a) and the materials (b) to (e) are preferably mixed in the order of (d), (b), (c), (a), and (e), while simultaneously protecting the OH groups of the lignin-derived substances in the biomass and sulfation of cellulose. Then, after a neutralization step (B) and a separation step (C), for the first solid component, by applying shear force while mixing and defibrinating in step (D), a composite of sulfation-derived cellulose nanofibers and lignin-derived substances is prepared from the composite of sulfation-derived cellulose and lignin-derived substances. By acid hydrolysis of sulfation-derived cellulose in step (D'), sulfation-derived cellulose nanocrystals are prepared. For the first liquid component, by depolymerizing the lignin-derived substances in step (D″′), monolignin alcohol is prepared. In parallel, each material derived from lignocellulose is manufactured.

[0223] Figure 9 In step (A), the dried lignocellulosic biomass (a) and the materials described in (b) to (e) are preferably mixed in the order of (d), (b), (c), (a), and (e), while simultaneously protecting the OH groups of the lignin-derived substances in the biomass and sulfation of the cellulose. Then, after a neutralization step (B) and a filtration (hemicellulose separation) step (C), the mixture is separated into a first solid component (containing uncrosslinked lignin-derived substances) and hemicellulose as a first liquid component. For the first solid component (containing uncrosslinked lignin-derived substances)... By applying shear force while mixing and defibrating (D), a composite of sulfated cellulose nanofibers and lignin-derived substances is prepared from the composite of sulfated cellulose and lignin-derived substances. By acid hydrolysis of sulfated cellulose (D'), sulfated cellulose nanocrystals are prepared. By adding THF (D”), filtering and washing, cellulose as the second solid component and lignin-derived substances as the second liquid component are obtained. The lignin-derived substances are depolymerized to prepare monolignin alcohol, and various materials derived from lignocellulose are manufactured in parallel.

[0224] The present invention also relates to a system for manufacturing materials derived from lignocellulose based on the manufacturing method of the present invention, and a control system for controlling the system.

[0225] Figure 10 This represents an example of the system of the present invention. Figure 11 This describes an example of a control system for the system of the present invention.

[0226] according to Figure 10 The system of the present invention includes:

[0227] (System used for process (A))

[0228] A dryer is used to dry lignocellulosic biomass as raw material to obtain dried lignocellulosic material;

[0229] A conveyor is used to connect the dryer to the reaction tank and to transport the dried lignocellulose mass from the dryer to the reaction tank;

[0230] A reaction tank is used to protect the OH groups of lignin-derived substances contained in lignocellulose in a dried lignocellulose mass conveyed by a conveyor, and to sulfate the cellulose and crosslink the sulfated cellulose with lignin-derived substances to obtain a crosslinked complex, thereby obtaining a reactant containing the crosslinked complex.

[0231] (System used for processes (B) to (C))

[0232] A conveyor, which connects the reaction tank and the neutralization-filtration-washing tank, is used to transport reactants from the reaction tank to the neutralization-filtration-washing tank;

[0233] Neutralization-filtration-washing tank, used to neutralize, filter and wash reactants conveyed by a conveyor to obtain solids (composed of cellulose with sulfate groups and lignin-derived substances, and the cellulose with sulfate groups and the lignin-derived substances form a cross-linked complex) and liquids.

[0234] (System used for process (D))

[0235] A conveyor that connects the neutralization-filtration-washing tank to the defiberization tank is used to transport solids from the neutralization-filtration-washing tank to the defiberization tank.

[0236] The defiber treatment tank is used to defiberize solids conveyed by a conveyor to obtain cellulose nanofibers with sulfate groups and lignin-derived substances, and the cellulose nanofibers with sulfate groups and the lignin-derived substances form a cross-linked composite.

[0237] A conveyor that connects the defiberization tank to the storage tank is used to transport the composite from the defiberization tank to the storage tank.

[0238] Storage tanks are used to store composites transported by conveyors;

[0239] (System used for process (D'))

[0240] A conveyor that connects the neutralization-filtration-washing tank to the hydrolysis tank is used to transport solids from the neutralization-filtration-washing tank to the hydrolysis tank;

[0241] Hydrolysis tank, used to hydrolyze solids conveyed by a conveyor to obtain a dispersion containing sulfated cellulose nanocrystals;

[0242] A conveyor connecting a hydrolysis tank and a filtration-washing tank is used to transport a dispersion containing sulfated cellulose nanocrystals from the hydrolysis tank to the filtration-washing tank.

[0243] A filtration-washing tank is used to filter and wash a dispersion containing sulfated cellulose nanocrystals conveyed by a conveyor to obtain sulfated cellulose nanocrystals.

[0244] A conveyor that connects the filter-washing tank to the disperser is used to transport sulfated cellulose nanocrystals from the filter-washing tank to the disperser;

[0245] A disperser is used to disperse sulfated cellulose nanocrystals conveyed by a conveyor to obtain dispersed sulfated cellulose nanocrystals.

[0246] A conveyor, which connects a disperser and a storage tank, is used to transport dispersed sulfated cellulose nanocrystals from the disperser to the storage tank;

[0247] Storage tanks are used to store dispersed sulfated cellulose nanocrystals conveyed by a conveyor.

[0248] A conveyor, which is connected to a filter-washing tank and an activated sludge tank, is used to transport activated sludge from the filter-washing tank to the activated sludge tank.

[0249] Activated sludge tanks are used to treat and store hydrocarbons transported by conveyors.

[0250] (System for process (D”))

[0251] A conveyor that connects the neutralization-filtration-washing tank to the distillation column is used to transport liquid from the neutralization-filtration-washing tank to the distillation column;

[0252] A distillation column that separates liquids conveyed by a conveyor into volatile and non-volatile components;

[0253] Solvent recovery tank or no component recovery tank is required; it is connected to a distillation column to recover volatile components.

[0254] The re-precipitation tank, which is connected to the distillation column, is used to recover non-volatile components and to add diethyl ether to the non-volatile components to obtain a suspension containing solids containing lignin and liquids containing hemicellulose.

[0255] A conveyor that connects a resedimentation tank and a filter is used to transport suspension from the resedimentation tank to the filter.

[0256] A filter used to separate solids and liquids from a suspension conveyed by a conveyor;

[0257] A conveyor connects the filter to the pressurized reaction tank, used to transport solids from the filter to the pressurized reaction tank.

[0258] A pressurized reaction vessel is used to depolymerize solids conveyed by a conveyor to obtain a liquid containing crude monolignin alcohols.

[0259] A conveyor, which connects the pressurized reaction tank and the distillation column, is used to convey liquid containing monolignin alcohol from the pressurized reaction tank to the distillation column;

[0260] A distillation column is used to separate and purify a liquid containing monolignin alcohols, which is conveyed by a conveyor, into individual components to obtain monolignin alcohols.

[0261] A conveyor, connected to a distillation column and a storage tank, is used to transport monolignin alcohol from the distillation column to the storage tank;

[0262] Storage tanks are used to store monolignin alcohols transported by conveyors;

[0263] A conveyor that connects a filter and an evaporator, used to transport liquid from the filter to the evaporator;

[0264] An evaporator is used to distill liquids conveyed by a conveyor to obtain hemicellulose and hydrocarbon-activated sludge as waste liquid.

[0265] A conveyor that connects the evaporator and the storage tank is used to transport hemicellulose from the evaporator to the storage tank;

[0266] Storage tanks are used to store hemicellulose transported by conveyors;

[0267] A conveyor connects the evaporator to the activated sludge tank and is used to transport hydrocarbons as waste liquid from the evaporator to the activated sludge tank.

[0268] according to Figure 11 The system of the present invention, through the control system of the present invention, enables the manufacturing method of the present invention to be easily implemented manually or automatically using the system of the present invention.

[0269] Example

[0270] The present invention will now be described in more detail with reference to embodiments, but the scope of the present invention is not limited thereto.

[0271] 1. Sample preparation

[0272] Sample A: Preparation of sulfated cellulose nanofibers

[0273] 3000g of dimethyl sulfoxide, 333g of acetic anhydride, and 43g of 98% sulfuric acid were added to a 5L flask and stirred with a stir bar. Next, 100g of pulp (NBKP, CARIBOO) was added, and the mixture was stirred at room temperature for 4 hours to perform sulfation. Then, a 5% sodium hydroxide aqueous solution was added dropwise to neutralize the pH of the reaction system to 7.0. The contents of the flask were then filtered through a nylon mesh (PA-11μ, AS ONE Co., Ltd.) and rinsed with distilled water. The resulting sulfation pulp was transferred to a 10L flask, and distilled water was added to achieve a solids concentration of 0.5%. The mixture was then subjected to ultrasonic treatment to obtain a 0.5% solids concentration sulfation cellulose nanofiber aqueous dispersion. Next, the sulfated cellulose nanofiber aqueous dispersion was frozen with liquid nitrogen and dried using a freeze dryer (FDU-12AS, manufactured by AS ONE Co., Ltd.) to obtain a dried sulfated cellulose nanofiber body (sample A) with an average fiber diameter of 10 nm.

[0274] Sample B: Preparation of sulfated cellulose nanofibers 2

[0275] In the preparation method of sample A, the amount of 98% sulfuric acid added was set to 66g. Otherwise, the preparation method of sample A was carried out in the same way, thereby obtaining a dried body of sulfated cellulose nanofibers with an average fiber diameter of 4nm (sample B).

[0276] Sample C: Preparation of sulfated cellulose nanofibers 3

[0277] In the preparation method of sample A, the amount of 98% sulfuric acid added was set to 33g. Otherwise, the preparation method of sample A was carried out in the same way, thereby obtaining a dried body of sulfated cellulose nanofibers with an average fiber diameter of 50nm (sample C).

[0278] Sample D: Preparation of sulfated cellulose nanofibers 4

[0279] In the preparation method of sample C, the stirring in the sulfation treatment was carried out at room temperature for 1 hour. Otherwise, the preparation method of sample C was carried out in the same way, thereby obtaining a dried body of sulfation cellulose nanofibers (sample D) with an average fiber diameter of 600 nm.

[0280] Sample E: Preparation of sulfated cellulose nanofibers 5

[0281] In the preparation method of sample C, the stirring in the sulfation treatment was carried out at room temperature for 0.5 hours. Otherwise, the preparation method of sample C was carried out in the same way, thereby obtaining a dried body of sulfation cellulose nanofibers with an average fiber diameter of 650 nm (sample E).

[0282] Sample F: Preparation of TEMPO oxidized cellulose nanofibers

[0283] 100g (absolutely dry) of NBKP, CARIBOO pulp was added to 5L of an aqueous solution containing 25mmol of 2,2,6,6-tetramethylpiperidine-N-oxide (TEMPO) and 200mmol of sodium bromide, and stirred until the pulp was uniformly dispersed. After maintaining the temperature at 20°C, 640mmol of an aqueous solution of sodium hypochlorite (manufactured by Fujifilm and Kojun Chemical Co., Ltd.) was added to the reaction system to initiate the oxidation reaction. The reaction was maintained at a constant temperature of 20°C. As the pH of the system decreased during the reaction, 3N sodium hydroxide aqueous solution was added sequentially to adjust the pH to 10. After 3 hours of reaction, the mixture was filtered through a glass filter and thoroughly washed with water to obtain oxidized pulp. A 1% (w / v) concentration of the obtained oxidized pulp was treated three times using an ultra-high pressure homogenizer (140MPa) to obtain a transparent, gel-like aqueous dispersion of TEMPO oxidized cellulose nanofibers. Next, the aqueous dispersion of TEMPO oxidized cellulose nanofibers was frozen with liquid nitrogen and dried using a freeze dryer (FDU-12AS, manufactured by AS ONE Co., Ltd.) to obtain a dried TEMPO oxidized cellulose nanofiber body (sample F) with an average fiber diameter of 10 nm.

[0284] Sample G: Preparation of phosphorylated cellulose nanofibers

[0285] A phosphorylation reagent was prepared by dissolving 100g of urea, 55.3g of sodium dihydrogen phosphate dihydrate, and 41.3g of disodium hydrogen phosphate in 109g of water. Dry papermaking sheets (NBKP, CARIBOO) were processed using a shredder and a needle mill to produce cotton-like fibers. 100g of these cotton-like fibers (by absolute dry weight) were sprayed with the phosphorylation reagent evenly using a sprayer and then kneaded by hand to obtain a drug-impregnated pulp. The drug-impregnated pulp was heated to 140°C using a forced-air dryer with a damper for 80 minutes to obtain phosphorylated pulp. 100g of the obtained phosphorylated pulp (by pulp weight) was added to 10L of ion-exchange water, stirred to ensure uniform dispersion, filtered, and dehydrated to obtain dehydrated tablets. This process was repeated twice. Next, the obtained dehydrated sheets were diluted with 10L of ion-exchange water, and 1N sodium hydroxide aqueous solution was added little by little while stirring to obtain a pulp with a pH of 12-13. Then, the pulp was dehydrated to obtain dehydrated sheets, which were then injected with 10L of ion-exchange water, stirred to disperse evenly, filtered, and dehydrated to obtain dehydrated sheets. This process was repeated twice. Ion-exchange water was added to the cellulose fibers obtained after dehydration and washing to prepare a 0.5% by mass pulp. The pulp was subjected to defiberization treatment for 180 minutes at 6900 rpm using a defiberization treatment device (CLEARMIX-11S, manufactured by M Technique Co., Ltd.). Then, ion-exchange water was added to adjust the pulp solids concentration to 0.25% by mass, and continuous centrifugation was performed using a cooled high-speed centrifuge (H-2000B, RN rotor, CKN1 current collector, manufactured by KOKUSAN Co., Ltd.). At this point, the defibrillation solution was delivered at a rate of 100 ml / min using a pump, and centrifuged at 18000 G. The supernatant was recovered to obtain an aqueous dispersion of phosphate-esterified cellulose nanofibers. Next, the aqueous dispersion of phosphate-esterified cellulose nanofibers was frozen with liquid nitrogen and dried using a freeze dryer (FDU-12AS, manufactured by AS ONE Co., Ltd.) to obtain a dried phosphate-esterified cellulose nanofiber body (sample G) with an average fiber diameter of 10 nm.

[0286] Sample H: Preparation of unmodified cellulose nanofibers

[0287] The aqueous dispersion of cellulose nanofibers (BiNFi-s, manufactured by SUGINO MACHI NELIMITED) was frozen with liquid nitrogen and then dried using a freeze dryer (FDU-12AS, manufactured by AS ONE Co., Ltd.) to obtain an unmodified dried cellulose nanofiber body (sample H).

[0288] Sample I: Preparation of cellulose nanofibers with both sulfate and carboxyl groups

[0289] In the preparation method of sample F, "100g of pulp (NBKP, CARIBOO) (absolutely dry)" was changed to "100g of sulfated cellulose nanofiber dry body of sample A". Otherwise, the preparation method of sample F was the same, thereby obtaining a cellulose nanofiber dry body (sample I) with an average fiber diameter of 10nm and containing sulfated and carboxyl groups.

[0290] Sample J: Preparation of cellulose nanofibers with both sulfate and phosphate groups

[0291] In the preparation method of sample G, the phrase "dry pulp (NBKP, CARIBOO) paper sheets are processed by a shredder and a pin mill to produce cotton-like fibers. The absolute dry weight of these cotton-like fibers is 100g" is changed to "100g of sulfated cellulose nanofiber dry body of sample A". Otherwise, the same preparation method as sample G is used to obtain a dry body of cellulose nanofibers (sample J) with an average fiber diameter of 10nm and containing both sulfated and phosphate groups.

[0292] Sample K: Preparation of cellulose nanofibers with both sulfate and acetyl groups

[0293] 100g of sulfated cellulose nanofiber dried body of sample A was immersed in a petri dish containing a reaction solution of acetic anhydride:acetic acid = 9:1 (volume ratio). The mixture was placed in a desiccator at room temperature under reduced pressure of 1 kPa for 30 minutes, allowing the reaction solution to permeate the sulfated cellulose nanofiber dried body. The pressure was then restored to normal, and the mixture was allowed to stand in the dark at room temperature under a N2 atmosphere for 5 days to undergo acetylation treatment. Next, the solid components were washed with methanol, running water, and distilled water, and then dried under reduced pressure at 60°C for 1 hour, thereby obtaining a cellulose nanofiber dried body (sample K) with an average fiber diameter of 10 nm and containing both sulfated and acetyl groups.

[0294] Example 1

[0295] In a beaker, 50g of sample A and 50g of sulfate lignin (Sigma-Aldrich, Indu linAT) were mixed using a spatula to obtain a mixture. Next, the mixture was heated to 100°C and passed through a three-roll mill (Model 1983, manufactured by Imoto Co., Ltd.) four times to prepare a 20μm thick sheet-like molded body composed of a lignin-derived composite (hydrogen-bonded complex) of sulfated cellulose nanofibers. Then, two of the obtained sheet-like molded bodies were sandwiched between a sheet of paper substrate (qualitative filter paper No. 2). A sheet-like laminate was prepared by overlapping two sides of a 0.26 mm thick layer of sulfated cellulose nanofibers (manufactured by ADVANTEC Co., Ltd.) on both sides and heating and pressurizing it for 2 minutes using a pressure molding machine (4-ton double-clamp hydraulic molding machine, manufactured by Iwaki Kogyo Co., Ltd.) heated to 100°C. Next, the laminate was cut using a sample cutter (SDL 200, manufactured by DUMBBELL Co., Ltd.) with a thickness of 0.26 mm, a width of 10 mm, and a length of 100 mm to prepare a dumbbell-shaped sample (Example 1) comprising a composite of sulfated cellulose nanofibers (50% solid cellulose nanofiber content) and a lignin-derived substance.

[0296] Example 2

[0297] In a 2000 mL flask, 730 g of dimethyl sulfoxide, 10.5 g of 98% sulfuric acid, 28.2 g of 37% formaldehyde aqueous solution, and 81.1 g of acetic anhydride were added and stirred with a stir bar. Next, 150 g of pine coniferous wood chips (as lignocellulose) were added to the flask, and the mixture was stirred at 95°C for 4 hours. This sulfation of the OH groups in the cellulose component and the cross-linking of the OH groups of the cellulose component with the OH groups of the lignin component via an acetal reaction using formaldehyde molecules were observed. At this point, the absorbance of the solution obtained by diluting the reaction solution 20 times was confirmed to be 0.4 at a wavelength of 500 nm. Then, 40% sodium hydroxide aqueous solution was added dropwise to adjust the pH to 7, thereby stopping the reaction. Next, 150 g of diethyl ether was added to precipitate the cellulose component and the lignin-derived substances, and to dissolve the hemicellulose component. Finally, the mixture was filtered through a nylon mesh (PA-11μ, manufactured by AS ONE Co., Ltd.) to remove the precipitate. The precipitate was dried at 105°C for 30 minutes to obtain a sulfated cellulose-lignin-derived material composite (containing cross-linked and uncross-linked components) with a cellulose solids content of 50%. Next, 80 g of the obtained sulfated cellulose-lignin-derived material composite was subjected to a three-roll mill process, similar to Example 1, to simultaneously perform nanofibrillation of the sulfated cellulose and obtain a sheet-like molded body with a thickness of 20 μm. Then, two sheets of the obtained molded body were sandwiched between one sheet of paper substrate (qualitative filter paper No. 2). A sheet-like laminate was formed by stacking two layers of material (0.26 mm thick, manufactured by ADVANTEC Co., Ltd.) on both sides and heating and pressurizing it for 2 minutes using a pressure molding machine (4-ton double-clamp hydraulic molding machine, manufactured by Iwaki Kogyo Co., Ltd.) heated to 100°C. This laminate was then cut into dumbbell shapes in the same manner as in Example 1, thus preparing a dumbbell-shaped sample (Example 2) comprising a composite (crosslinked composite) of sulfated cellulose nanofibers and lignin-derived substances with a solid component ratio of 50%. Furthermore, 2 g of the sulfated cellulose nanofiber-lignin-derived substance composite was added to a pressure reactor (Series 4560, manufactured by Parr Co., Ltd.), along with 1 g of 5% ruthenium carbon and 200 ml of THF, and hydrogen was injected at an inlet pressure of 4 MPa. The pressure reactor was then heated at 200°C for 3 hours and cooled to room temperature. Next, the oligomers and ruthenium carbon derived from lignin, which are solid components, are removed using a nylon mesh (PA-11μ, manufactured by AS ONE Co., Ltd.) to obtain the soluble component. Then, the solvent is removed from the soluble component by distillation using an evaporator, thereby obtaining monolignin alcohol.

[0298] Example 3

[0299] In a beaker, 5g of sample A, 5g of sulfated lignin (Sigma-Aldrich, Indulin AT), and 90g of low-density polyethylene particles (SANPLATEC, Ltd.) were mixed using a spatula to obtain a mixture. Next, the mixture was subjected to three-roll mill processing, lamination with paper substrate, and dumbbell-shaped cutting, similar to Example 1, thereby preparing a dumbbell-shaped sample (Example 3) comprising a composite (hydrogen-bonded complex) of sulfated cellulose nanofibers (5% solid cellulose nanofiber content) and lignin-derived substances, and low-density polyethylene.

[0300] Example 4

[0301] In a beaker, 10 g of a composite of sulfated cellulose nanofibers with a cellulose solids content of 50% obtained by the method of Example 2 and 90 g of low-density polyethylene particles (manufactured by SANPATEC) were mixed with a scraper and processed in the same way as in Example 1. This produced a dumbbell-shaped sample (Example 4) comprising a composite of sulfated cellulose nanofibers with a cellulose nanofibers solids content of 5% (crosslinked composite) and low-density polyethylene.

[0302] Example 5

[0303] In Example 3, the "low-density polyethylene particles" were changed to "PHBH particles (manufactured by KANEKA Co., Ltd.)". Otherwise, the same procedure as in Example 3 was followed to prepare a dumbbell-shaped sample (Example 5) comprising a composite of sulfated cellulose nanofibers (a lignin-derived substance) with a solid component ratio of 5% cellulose nanofibers and PHBH.

[0304] Example 6

[0305] In Example 4, the "low-density polyethylene particles" were changed to "PHBH particles (manufactured by KANEKA Co., Ltd.)". Otherwise, the same procedure as in Example 4 was followed to prepare a dumbbell-shaped sample (Example 6) comprising a composite of sulfated cellulose nanofibers (a lignin-derived substance) with a solid component ratio of 5% cellulose nanofibers and PHBH.

[0306] Example 7

[0307] Using a rotary mixer (THINKY Co., Ltd.), 5g of sample A, 5g of sulfate lignin (Indulin AT, Sigma-Aldrich) and 180g of natural rubber latex (KENIS Co., Ltd.) with a solids content of 50% by weight were mixed at room temperature. Next, the obtained mixture was placed in a TEFL ON (registered trademark) tray and dried at 80°C for 3 days. Then, 3g of free radical initiator (PERHEX A25B-40, manufactured by Nippon Oil Co., Ltd.) was added, and the mixture was passed through a three-roll mill (three-roll mill type 1983, manufactured by Imoto Manufacturing Co., Ltd.) at 100°C 4 times to prepare a sheet-like composite containing sulfated cellulose nanofibers-lignin-derived substances and natural rubber with a thickness of 20μm. Then, the composite was laminated with a paper substrate and cut into dumbbell shapes in the same manner as in Example 1 to prepare a dumbbell-shaped sample (Example 7) containing a composite of sulfated cellulose nanofibers-lignin-derived substances (hydrogen-bonded composite) with a solid component ratio of 5% cellulose nanofibers and natural rubber.

[0308] Example 8

[0309] 180g of natural rubber latex (manufactured by KENIS Co., Ltd.) with a solid content concentration of 50% by weight was mixed with 10g of a composite of sulfated cellulose nanofibers and lignin-derived substances with a solid content of 50% as in Example 2. The resulting mixture was placed in a TEF LON (registered trademark) tray and dried at 80°C for 3 days. Next, 3g of the dried natural rubber latex and 3g of free radical initiator (PERHEXA25B-40, manufactured by Nippon Oil Co., Ltd.) were added, and the mixture was passed through a three-roll mill (model 1983, manufactured by Imoto Manufacturing Co., Ltd.) heated to 100°C four times to prepare a sheet-like molded body with a thickness of 20μm, consisting of a composite of sulfated cellulose nanofibers and lignin-derived substances and natural rubber. Next, the molded body was laminated with a paper substrate and cut into a dumbbell shape in the same manner as in Example 1, thereby preparing a dumbbell-shaped sample (Example 8) comprising a composite (hydrogen-bonded composite) of sulfated cellulose nanofibers with a solid component ratio of 5% cellulose nanofibers and lignin-derived substances and a molded body of natural rubber.

[0310] Example 9

[0311] In Example 1, the phrase "mixing 50g of sample A and 50g of sulfate lignin (Sigma-Aldrich, Indulin AT) in a beaker using a spatula" was changed to "mixing 50g of sample A, 50g of sulfate lignin (Sigma-Aldrich, Indulin AT), and 1g of silica (HS-208, NIPPO N STEEL Chemical & Material Co., Ltd.) in a beaker using a spatula." Otherwise, the same procedure as in Example 1 was followed to prepare a dumbbell-shaped sample (Example 9) comprising a composite of sulfated cellulose nanofibers (a lignin-derived substance) with a solid component ratio of 50% cellulose nanofibers and silica.

[0312] Example 10

[0313] In Example 2, the phrase "the obtained sulfated cellulose nanofiber-lignin-derived material composite was subjected to three-roll mill treatment in the same manner as in Example 1" was changed to "100g of the obtained sulfated cellulose nanofiber-lignin-derived material composite and 1g of silica (HS-208, manufactured by NIPPON STEELC Chemical & Material Co., Ltd.) were subjected to three-roll mill treatment in the same manner as in Example 1." Otherwise, the same procedure as in Example 2 was followed to prepare a dumbbell-shaped sample (Example 10) comprising a composite of sulfated cellulose nanofiber-lignin-derived material (crosslinked composite) with a solid component ratio of 50% cellulose nanofiber and silica.

[0314] Example 11

[0315] In Example 3, the process of "mixing 5g of sample A, 5g of sulfated lignin (manufactured by Sigma-Aldrich, Indulin AT) and 90g of low-density polyethylene particles (manufactured by SANPLATEC) in a beaker using a spatula" was changed to "mixing 5g of sample A, 5g of sulfated lignin (manufactured by Sigma-Aldrich, Indulin AT), 90g of low-density polyethylene particles (manufactured by SANPLATEC) and 1g of silica (HS-208, manufactured by NIPPON STEEL Chemical & Material Co., Ltd.) in a beaker using a spatula" was repeated. Otherwise, the same procedure as in Example 3 was followed to prepare a dumbbell-shaped sample (Example 11) comprising a composite of sulfated cellulose nanofibers (a lignin-derived substance with a solid component ratio of 5% cellulose nanofibers), low-density polyethylene, and silica.

[0316] Example 12

[0317] In Example 4, the description of "preparing a mixture by mixing 10g of a composite of sulfated cellulose nanofibers (50% solid component) and lignin-derived substances, and 90g of low-density polyethylene particles (manufactured by SANPLATEC) in a beaker using a scraper, and then processing the mixture using a three-roll mill in the same manner as in Example 1" is changed to "preparing a mixture by mixing 10g of a composite of sulfated cellulose nanofibers (50% solid component) and lignin-derived substances, 90g of low-density polyethylene particles (manufactured by SANPLATEC), and silica (HS-208, NIPPON STEEL) in a beaker using a scraper." A mixture was prepared by mixing 1g of (manufactured by Chemical & Material Co., Ltd.) and the mixture was subjected to three-roll mill processing in the same manner as in Example 1. Otherwise, the process was the same as in Example 4, thereby preparing a dumbbell-shaped sample (Example 12) comprising a composite (crosslinked composite) of sulfated cellulose nanofibers-lignin-derived material with a nanofiber solid component ratio of 5%, low-density polyethylene, and silica.

[0318] Example 13

[0319] In Example 1, the phrase "mixing 50g of sample A and 50g of sulfate lignin (Sigma-Aldrich, Indulin AT) in a beaker using a spatula" was changed to "mixing 0.03g of sample A and 99.97g of sulfate lignin (Sigma-Aldrich, Indulin AT) in a beaker using a spatula." Otherwise, the same procedure as in Example 1 was followed to prepare a dumbbell-shaped sample (Example 13) comprising a composite of sulfated cellulose nanofibers and lignin-derived substances (hydrogen-bonded composites) with a cellulose nanofiber solid component ratio of 0.03%.

[0320] Example 14

[0321] In Example 1, the phrase "mixing 50g of sample A and 50g of sulfate lignin (Sigma-Aldrich, Indulin AT) in a beaker using a spatula" was changed to "mixing 0.05g of sample A and 99.95g of sulfate lignin (Sigma-Aldrich, Indulin AT) in a beaker using a spatula." Otherwise, the same procedure as in Example 1 was followed to prepare a dumbbell-shaped sample (Example 14) comprising a composite of sulfated cellulose nanofibers and lignin-derived substances (hydrogen-bonded composites) with a cellulose nanofiber solid component ratio of 0.05%.

[0322] Example 15

[0323] In Example 1, the phrase "mixing 50g of sample A and 50g of sulfate lignin (Sigma-Aldrich, Indulin AT) in a beaker using a spatula" was changed to "mixing 5g of sample A and 95g of sulfate lignin (Sigma-Aldrich, Indulin AT) in a beaker using a spatula." Otherwise, the same procedure as in Example 1 was followed to prepare a dumbbell-shaped sample (Example 15) comprising a composite of sulfated cellulose nanofibers and lignin-derived substances (hydrogen-bonded composites) with a solid component ratio of 5% cellulose nanofibers.

[0324] Example 16

[0325] In Example 1, the phrase "mixing 50g of sample A and 50g of sulfate lignin (Sigma-Aldrich, Indulin AT) in a beaker using a spatula" was changed to "mixing 30g of sample A and 70g of sulfate lignin (Sigma-Aldrich, Indulin AT) in a beaker using a spatula." Otherwise, the same procedure as in Example 1 was followed to prepare a dumbbell-shaped sample (Example 16) comprising a composite of sulfated cellulose nanofibers and lignin-derived substances (hydrogen-bonded complex) with a solid component ratio of 30% cellulose nanofibers.

[0326] Example 17

[0327] In Example 1, the phrase "mixing 50g of sample A and 50g of sulfate lignin (Sigma-Aldrich, Indulin AT) in a beaker using a spatula" was changed to "mixing 80g of sample A and 20g of sulfate lignin (Sigma-Aldrich, Indulin AT) in a beaker using a spatula." Otherwise, the same procedure as in Example 1 was followed to prepare a dumbbell-shaped sample (Example 17) comprising a composite of sulfated cellulose nanofibers and lignin-derived substances (hydrogen-bonded composites) with a solid component ratio of 80% cellulose nanofibers.

[0328] Example 18

[0329] In Example 1, the phrase "mixing 50g of sample A and 50g of sulfate lignin (Sigma-Aldrich, Indulin AT) in a beaker using a spatula" was changed to "mixing 85g of sample A and 15g of sulfate lignin (Sigma-Aldrich, Indulin AT) in a beaker using a spatula." Otherwise, the procedure was the same as in Example 1, and a dumbbell-shaped sample (Example 18) comprising a composite of sulfated cellulose nanofibers and lignin-derived substances (hydrogen-bonded complex) with a solid component ratio of 85% cellulose nanofibers was prepared.

[0330] Example 19

[0331] In Example 2, the phrase "stirring at 95°C for 4 hours" was changed to "stirring at 95°C for 1 hour, removing a portion (20.5 g) of the fibrous component, and then stirring at 95°C for 3 hours." Otherwise, the same procedure as in Example 2 was followed to prepare a dumbbell-shaped sample (Example 19) comprising a composite (crosslinked composite) of sulfated cellulose nanofibers and lignin-derived substances with a solid component ratio of 5%.

[0332] Example 20

[0333] In Example 1, "Sample A" was changed to "Sample B". Otherwise, the same procedure was followed as in Example 1 to prepare a dumbbell-shaped sample (Example 20) comprising a composite (hydrogen-bonded complex) of sulfated cellulose nanofibers with a solid component ratio of 50% cellulose nanofibers and a lignin-derived substance.

[0334] Example 21

[0335] In Example 1, “Sample A” was changed to “Sample C”. Otherwise, the same procedure was followed as in Example 1 to prepare a dumbbell-shaped sample (Example 21) comprising a composite of sulfated cellulose nanofibers (hydrogen-bonded complex) and lignin-derived substances, with a solid component ratio of 50% cellulose nanofibers.

[0336] Example 22

[0337] In Example 1, “Sample A” was changed to “Sample D”. Otherwise, the same procedure was followed as in Example 1 to prepare a dumbbell-shaped sample (Example 22) comprising a composite of sulfated cellulose nanofibers (hydrogen-bonded complex) with a solid component ratio of 50% cellulose nanofibers and a lignin-derived substance.

[0338] Example 23

[0339] In Example 1, "Sample A" was changed to "Sample E". Otherwise, the same procedure was followed as in Example 1 to prepare a dumbbell-shaped sample (Example 23) comprising a composite of sulfated cellulose nanofibers (hydrogen-bonded complex) with a solid component ratio of 50% cellulose nanofibers and a lignin-derived substance.

[0340] Example 24

[0341] In Example 1, the process of "heating the mixture to 100°C and passing it through 4 times using a three-roll mill (three-roll mill model 1983, manufactured by Imoto Manufacturing Co., Ltd.)" was changed to "using a twin-screw mixer (KRC Junior ultra-small continuous twin-screw mixer, manufactured by Kurimoto Iron Works Co., Ltd.) to mix the mixture, and then pressing it using a pressure molding machine heated to 100°C (4-ton double-fastening hydraulic molding machine, manufactured by Iwaki Industrial Co., Ltd.). Otherwise, the process was the same as in Example 1, and a dumbbell-shaped sample (Example 24) containing a composite of sulfated cellulose nanofibers and lignin-derived substances with a solid component ratio of 50% cellulose nanofibers was prepared.

[0342] Example 25

[0343] In Example 2, the procedure of “treating the obtained sulfated cellulose nanofiber-lignin-derived material composite with a three-roll mill in the same manner as in Example 1” was changed to “treating the obtained sulfated cellulose nanofiber-lignin-derived material composite with a twin-screw mixer in the same manner as in Example 24”. Otherwise, the procedure was the same as in Example 2, and a dumbbell-shaped sample (Example 25) comprising a composite of sulfated cellulose nanofiber-lignin-derived material (crosslinked composite) with a solid component ratio of 50% cellulose nanofiber was prepared.

[0344] Example 26

[0345] In Example 3, the process of "treating the mixture with a three-roll mill, preparing a laminate with a paper substrate, and cutting it into a dumbbell shape, as in Example 1" was changed to "treating the mixture with a twin-screw mixer, preparing a laminate with a paper substrate, and cutting it into a dumbbell shape, as in Example 24". Otherwise, the process was the same as in Example 3, and a dumbbell-shaped sample (Example 26) was prepared, which consisted of a composite (hydrogen-bonded composite) of sulfated cellulose nanofibers with a solid component ratio of 5% cellulose nanofibers and a lignin-derived substance.

[0346] Example 27

[0347] In Example 4, the phrase "the mixture was processed by a three-roll mill in the same manner as in Example 1" was changed to "the mixture was processed by a twin-screw mixer in the same manner as in Example 24". Otherwise, the process was the same as in Example 4, and a dumbbell-shaped sample (Example 27) was prepared comprising a composite (crosslinked composite) of sulfated cellulose nanofibers with a solid component ratio of 5% cellulose nanofibers and lignin-derived substances and low-density polyethylene.

[0348] Example 28

[0349] In Example 1, the phrase "the mixture was heated to 100°C and passed through it 4 times using a three-roll mill (three-roll mill type 1983, manufactured by Imoto Manufacturing Co., Ltd.)" was changed to "the mixture was pressed using a pressure molding machine (4-ton double-clamp hydraulic molding machine, manufactured by Iwaki Industrial Co., Ltd.) heated at 100°C". Otherwise, the same procedure as in Example 1 was followed to prepare a dumbbell-shaped sample (Example 28) containing a composite (hydrogen-bonded complex) of sulfated cellulose nanofibers with a solid component ratio of 50% cellulose nanofibers and a lignin-derived substance.

[0350] Example 29

[0351] In Example 2, the procedure of “treating the obtained sulfated cellulose nanofiber-lignin-derived material composite with a three-roll mill as in Example 1” was changed to “treating the obtained sulfated cellulose nanofiber-lignin-derived material composite with a pressure molding machine as in Example 28”. Otherwise, the procedure was the same as in Example 2, and a dumbbell-shaped sample (Example 29) comprising a composite of sulfated cellulose nanofiber-lignin-derived material (crosslinked composite) with a solid component ratio of 50% cellulose nanofiber was prepared.

[0352] Example 30

[0353] In Example 3, the process of “treating the mixture with a three-roll mill, preparing a laminate with a paper substrate, and cutting it into a dumbbell shape, as in Example 1” was changed to “treating the mixture with a pressure molding machine, preparing a laminate with a paper substrate, and cutting it into a dumbbell shape, as in Example 28”. Otherwise, the process was the same as in Example 3, and a dumbbell-shaped sample (Example 30) was prepared comprising a composite (hydrogen-bonded composite) of sulfated cellulose nanofibers with a solid component ratio of 5% cellulose nanofibers and lignin-derived substances and low-density polyethylene.

[0354] Example 31

[0355] In Example 4, the phrase "the mixture was processed by a three-roll mill in the same manner as in Example 1" was changed to "the mixture was processed by a pressure molding machine in the same manner as in Example 28". Otherwise, the process was the same as in Example 4, and a dumbbell-shaped sample (Example 31) was prepared, which consisted of a composite (crosslinked composite) of sulfated cellulose nanofibers with a solid component ratio of 5% cellulose nanofibers and a lignin-derived substance and low-density polyethylene.

[0356] Example 32

[0357] In Example 2, “28.2g of 37% formaldehyde aqueous solution” was changed to “19.7g of acetone”. Otherwise, the same procedure as in Example 2 was followed to prepare a dumbbell-shaped sample (Example 32) comprising a composite (crosslinked composite) of sulfated cellulose nanofibers and lignin-derived substances with a solid component ratio of 50% cellulose nanofibers.

[0358] Example 33

[0359] In Example 2, "28.2g of 37% formaldehyde aqueous solution" was changed to "41.4g of phenylboronic acid". Otherwise, the same procedure as in Example 2 was followed to prepare a dumbbell-shaped sample (Example 33) comprising a composite (crosslinked composite) of sulfated cellulose nanofibers and lignin-derived substances with a solid component ratio of 50% cellulose nanofibers.

[0360] Example 34

[0361] In Example 2, “28.2 g of 37% formaldehyde aqueous solution” was changed to “24.4 g of 2-methoxypropylene”. Otherwise, the same procedure as in Example 2 was followed to prepare a dumbbell-shaped sample (Example 34) comprising a composite (crosslinked composite) of sulfated cellulose nanofibers and lignin-derived substances with a solid component ratio of 50% cellulose nanofibers.

[0362] Example 35

[0363] In Example 2, “37% formaldehyde aqueous solution 28.2g” was changed to “dimethyl carbonate 30.5g”. Otherwise, the same procedure as in Example 2 was followed to prepare a dumbbell-shaped sample (Example 35) comprising a composite (crosslinked composite) of sulfated cellulose nanofibers and lignin-derived substances with a solid component ratio of 50% cellulose nanofibers.

[0364] Example 36

[0365] In Example 2, “37% formaldehyde aqueous solution 28.2g” was changed to “2,2-dimethoxypropane 35.3g”. Otherwise, the same procedure as in Example 2 was followed to prepare a dumbbell-shaped sample (Example 36) comprising a composite (crosslinked composite) of sulfated cellulose nanofibers and lignin-derived substances with a solid component ratio of 50% cellulose nanofibers.

[0366] Example 37

[0367] In Example 2, “acetic anhydride 81.1g” was changed to “propionic anhydride 103.2g”. Otherwise, the same procedure as in Example 2 was followed to prepare a dumbbell-shaped sample (Example 37) comprising a composite (crosslinked composite) of sulfated cellulose nanofibers and lignin-derived substances with a solid component ratio of 50% cellulose nanofibers.

[0368] Example 38

[0369] In Example 2, the procedure was changed from "adding 730g of dimethyl sulfoxide, 10.5g of 98% sulfuric acid, 28.2g of 37% formaldehyde aqueous solution, and 81.1g of acetic anhydride to a 2000ml flask, stirring with a stir bar, and then adding 150g of pine coniferous wood chips as lignocellulose to the flask and stirring at 95°C for 4 hours" to "adding 730g of dimethyl sulfoxide, 10.5g of 98% sulfuric acid, 28.2g of 37% formaldehyde aqueous solution, and 150g of pine coniferous wood chips to a 2000ml flask in the order described, stirring at 95°C for 30 minutes, then adding 81.1g of acetic anhydride and stirring at 95°C for 4 hours." Otherwise, the procedure was the same as in Example 2, thereby preparing a dumbbell-shaped sample (Example 38) comprising a composite (crosslinked composite) of sulfated cellulose nanofibers and lignin-derived substances with a cellulose nanofiber solid component ratio of 50%.

[0370] Example 39

[0371] In Example 2, the procedure was changed from "adding 730g of dimethyl sulfoxide, 10.5g of 98% sulfuric acid, 28.2g of 37% formaldehyde aqueous solution, and 81.1g of acetic anhydride to a 2000ml flask, stirring with a stir bar, and then adding 150g of pine coniferous wood chips as lignocellulose to the flask and stirring at 95°C for 4 hours" to "adding 730g of dimethyl sulfoxide, 10.5g of 98% sulfuric acid, 28.2g of 37% formaldehyde aqueous solution, 150g of pine coniferous wood chips, and 81.1g of acetic anhydride to a 2000ml flask in the order described, stirring at 95°C for 30 minutes, and then adding an additional 81.1g of acetic anhydride." Otherwise, the procedure was the same as in Example 2, thereby preparing a dumbbell-shaped sample (Example 39) comprising a composite (crosslinked composite) of sulfated cellulose nanofibers and lignin-derived substances with a cellulose nanofiber solid component ratio of 50%.

[0372] Example 40

[0373] In Example 2, the procedure of "adding 730g of dimethyl sulfoxide, 10.5g of 98% sulfuric acid, 28.2g of 37% formaldehyde aqueous solution, and 81.1g of acetic anhydride to a 2000ml flask, stirring with a stir bar, and then adding 150g of pine coniferous wood chips as lignocellulose to the flask and stirring at 95°C for 4 hours" was changed to "adding 730g of dimethyl sulfoxide, 10.5g of 98% sulfuric acid, 28.2g of 37% formaldehyde aqueous solution, and 150g of pine coniferous wood chips to a 2000ml flask in the order described, stirring at 95°C for 30 minutes, and then adding 81.1g of acetic anhydride after cooling to 45°C." Otherwise, the procedure was the same as in Example 2, and a dumbbell-shaped sample (Example 40) containing a composite of sulfated cellulose nanofibers and lignin-derived substances (crosslinked composite) with a cellulose nanofiber solid component ratio of 50% was prepared.

[0374] Example 41

[0375] In Example 2, the procedure was changed from "sulfating the OH groups in the cellulose component by stirring at 95°C for 4 hours, and cross-linking the OH groups of the cellulose component with the OH groups of the lignin component using formaldehyde molecules via an acetal reaction, at which point it was confirmed that the absorbance of the solution obtained by diluting the reaction solution 20 times at a wavelength of 500 nm was 0.4" to "sulfating the OH groups in the cellulose component by stirring at 95°C for 5 hours, and cross-linking the OH groups of the cellulose component with the OH groups of the lignin component using formaldehyde molecules via an acetal reaction, at which point it was confirmed that the absorbance of the solution obtained by diluting the reaction solution 20 times at a wavelength of 500 nm was 0.5". Otherwise, the procedure was the same as in Example 2, and a dumbbell-shaped sample (Example 41) containing a composite (cross-linked composite) of sulfated cellulose nanofibers with a solid component ratio of 50% cellulose nanofibers and lignin-derived substances was prepared.

[0376] Example 42

[0377] In Example 2, the phrase "150g of pine coniferous wood chips as lignocellulose were added to the flask" was changed to "35g of pine coniferous wood chips as lignocellulose were added to the flask." Otherwise, the same procedure as in Example 2 was followed to prepare a dumbbell-shaped sample (Example 42) comprising a composite (crosslinked composite) of sulfated cellulose nanofibers and lignin-derived substances with a solid component ratio of 50% cellulose nanofibers.

[0378] Example 43

[0379] In Example 2, the phrase "150g of pine coniferous wood chips as lignocellulose were added to the flask" was changed to "45g of pine coniferous wood chips as lignocellulose were added to the flask." Otherwise, the same procedure as in Example 2 was followed to prepare a dumbbell-shaped sample (Example 43) comprising a composite (crosslinked composite) of sulfated cellulose nanofibers and lignin-derived substances, with a solid component ratio of 50% cellulose nanofibers.

[0380] Example 44

[0381] In Example 2, the phrase "150g of pine coniferous wood chips as lignocellulose were added to the flask" was changed to "364g of pine coniferous wood chips as lignocellulose were added to the flask." Otherwise, the same procedure as in Example 2 was followed to prepare a dumbbell-shaped sample (Example 44) comprising a composite (crosslinked composite) of sulfated cellulose nanofibers and lignin-derived substances, with a solid component ratio of 50% cellulose nanofibers.

[0382] Example 45

[0383] In Example 2, the phrase "150g of pine coniferous wood chips as lignocellulose were added to the flask" was changed to "849g of pine coniferous wood chips as lignocellulose were added to the flask." Otherwise, the same procedure as in Example 2 was followed to prepare a dumbbell-shaped sample (Example 45) comprising a composite (crosslinked composite) of sulfated cellulose nanofibers and lignin-derived substances, with a cellulose nanofiber solid component ratio of 50%.

[0384] Example 46

[0385] In Example 2, the phrase "150g of pine coniferous wood chips as lignocellulose were added to the flask" was changed to "1038g of pine coniferous wood chips as lignocellulose were added to the flask." Otherwise, the same procedure as in Example 2 was followed to prepare a dumbbell-shaped sample (Example 46) comprising a composite (crosslinked composite) of sulfated cellulose nanofibers and lignin-derived substances, with a solid component ratio of 50% cellulose nanofibers.

[0386] Example 47

[0387] 730 g of dimethyl sulfoxide, 10.5 g of 98% sulfuric acid, 28.2 g of 37% formaldehyde aqueous solution, and 81.1 g of acetic anhydride were added to a 2000 mL flask and stirred with a stir bar. Next, 150 g of pine coniferous wood chips (as lignocellulose) were added to the flask, and the mixture was stirred at 95°C for 4 hours. At this point, the absorbance of the solution obtained by diluting the reaction solution 20 times was confirmed to be 0.4 at a wavelength of 500 nm. The mixture was then filtered through a nylon mesh (PA-11μ, manufactured by AS ONE Co., Ltd.) to collect the solid components.

[0388] Prepare a new 1L flask, add the extracted solid components, and further add 500ml of 58% sulfuric acid, then heat to 50°C. Next, add the solid components extracted by filtration through a nylon mesh to the newly prepared 1L flask and stir for 3 hours. Then, process the contents of the 1L flask using a centrifuge (CT18R, manufactured by Eppendorf Himac Technologies Co., Ltd.) at 20000G for 10 minutes. Next, remove the supernatant by decantation, and add 400ml of distilled water to suspend the particles. Then, perform two sets of "centrifuge treatment - removal of supernatant by decantation - suspension of particles by adding 400ml of distilled water" to prepare a sulfated cellulose nanocrystal aqueous dispersion (Example 47).

[0389] Example 48

[0390] In a 2000 mL flask, 730 g of dimethyl sulfoxide, 10.5 g of 98% sulfuric acid, 28.2 g of 37% formaldehyde aqueous solution, and 81.1 g of acetic anhydride were added and stirred with a stir bar. Next, 150 g of pine coniferous wood chips (as lignocellulose) were added to the flask, and the mixture was stirred at 95°C for 4 hours. At this point, the absorbance of the solution obtained by diluting the reaction solution 20 times was confirmed to be 0.4 at a wavelength of 500 nm. Then, 40% sodium hydroxide aqueous solution was added dropwise to adjust the pH to 7, thereby stopping the reaction. The mixture was then filtered through a nylon mesh (PA-11μ, manufactured by AS ONE Co., Ltd.) to remove the solid components derived from cellulose, yielding a brownish-red soluble component. Next, 510 g of diethyl ether was added to the soluble component to precipitate the lignin-derived components and dissolve the hemicellulose components. Finally, the mixture was filtered through a nylon mesh (PA-11μ, manufactured by AS ONE Co., Ltd.) to obtain the lignin-derived components. In a pressure reactor (Series 4560, manufactured by Parr), 2 g of a lignin-derived substance, 1 g of 5% ruthenium carbon, and 200 ml of THF were added, and hydrogen was injected at an inlet pressure of 4 MPa. The pressure reactor was then heated at 200°C for 3 hours and cooled to room temperature. The lignin-derived oligomers and ruthenium carbon, which were solid components, were then removed using a nylon mesh (PA-11μ, manufactured by AS ONE Co., Ltd.) to obtain the soluble component. The solvent was then removed by distillation from the soluble component using an evaporator, thereby obtaining monolignin alcohol (Example 48).

[0391] Example 49

[0392] In Example 1, “Sample A” was changed to “Sample I”. Otherwise, the same procedure was followed as in Example 1 to prepare a dumbbell-shaped sample (Example 49) comprising a cellulose nanofiber-lignin-derived material complex (hydrogen-bonded complex) having a solid component of 50% cellulose nanofibers and containing both sulfate ester groups and carboxyl groups.

[0393] Example 50

[0394] In Example 1, “Sample A” was changed to “Sample J”. Otherwise, the same procedure as in Example 1 was followed to prepare a dumbbell-shaped sample (Example 50) consisting of a cellulose nanofiber-lignin-derived material complex (hydrogen-bonded complex) with a solid component ratio of 50% cellulose nanofibers and containing both sulfate and phosphate groups.

[0395] Example 51

[0396] In Example 1, “Sample A” was changed to “Sample K”. Otherwise, the same procedure was followed as in Example 1 to prepare a dumbbell-shaped sample (Example 51) comprising a cellulose nanofiber-lignin-derived material complex (hydrogen-bonded complex) having a solid component of 50% cellulose nanofibers and containing both sulfate ester groups and acetyl groups.

[0397] Comparative Example 1

[0398] In Example 1, “Sample A” was changed to “Sample F”. Otherwise, the same procedure was followed as in Example 1 to prepare a dumbbell-shaped sample (Comparative Example 1) comprising a composite of TEMPO oxidized cellulose nanofibers (hydrogen-bonded composite) with a solid component ratio of 50% cellulose nanofibers and a lignin-derived substance.

[0399] Comparative Example 2

[0400] 730 g of dimethyl sulfoxide, 10.5 g of 98% sulfuric acid, and 28.2 g of 37% formaldehyde aqueous solution were added to a 2000 mL flask and stirred with a stir bar. Next, 50 g of sample F and 50 g of sulfate lignin (Sigma-Aldrich, Indulin AT) were added to the flask, and the mixture was stirred at 95°C for 4 hours. This process caused the OH groups in the TEMPO oxidized cellulose nanofiber molecules and the OH groups in the sulfate lignin to undergo acetalization by formaldehyde molecules, resulting in a TEMPO oxidized cellulose nanofiber-lignin-derived material composite (crosslinked composite). The obtained TEMPO oxidized cellulose nanofiber-lignin-derived material composite was then subjected to a three-roll mill process, similar to Example 1, to obtain a sheet-like molded body with a thickness of 20 μm. Finally, two sheets of the obtained molded body were sandwiched between one sheet of paper substrate (qualitative filter paper No. 2). A sheet-like laminate was formed by stacking two layers of material (0.26 mm thick, manufactured by ADVANTEC Co., Ltd.) on both sides and heating and pressurizing it for 2 minutes using a pressure molding machine (4-ton double-clamp hydraulic molding machine, manufactured by Iwaki Kogyo Co., Ltd.) heated to 100°C. Next, the laminate was cut into a dumbbell shape in the same manner as in Example 1, thus preparing a dumbbell-shaped sample (Comparative Example 2) comprising a composite (crosslinked composite) of TEMPO oxidized cellulose nanofibers (50% solid cellulose nanofiber content) and a lignin-derived substance.

[0401] Comparative Example 3

[0402] In Example 1, “Sample A” was changed to “Sample G”. Otherwise, the same procedure was followed as in Example 1 to prepare a dumbbell-shaped sample (Comparative Example 3) comprising a complex (hydrogen-bonded complex) of phosphorylated cellulose nanofibers with a solid component ratio of 50% cellulose nanofibers and a lignin-derived substance.

[0403] Comparative Example 4

[0404] In Comparative Example 2, "Sample F" was changed to "Sample G". Otherwise, the same procedure was followed as in Comparative Example 2 to prepare a dumbbell-shaped sample (Comparative Example 4) comprising a composite (crosslinked composite) of phosphorylated cellulose nanofibers with a solid component ratio of 50% cellulose nanofibers and a lignin-derived substance.

[0405] Comparative Example 5

[0406] In Example 1, “Sample A” was changed to “Sample H”. Otherwise, the same procedure was followed as in Example 1 to prepare a dumbbell-shaped sample (Comparative Example 5) comprising a composite of unmodified cellulose nanofibers and lignin-derived substances (hydrogen-bonded composites) with a solid component ratio of 50% cellulose nanofibers.

[0407] Comparative Example 6

[0408] In Example 2, "dimethyl sulfoxide" was replaced with "dimethylformamide", and acetic anhydride was not added. Otherwise, the same procedure as in Example 2 was followed to prepare a dumbbell-shaped sample (Comparative Example 6) comprising a composite of cellulose nanofibers and lignin-derived substances with a solid component ratio of 5%.

[0409] Comparative Example 7

[0410] 100g of sulfate lignin (Sigma-Aldrich, Indulin AT) was passed through a three-roll mill (Model 1983, manufactured by Imoto Corporation) four times while being heated to 100°C, thereby preparing a sheet-like molded body with a thickness of 20μm composed of lignin-derived material. Next, two of the obtained sheet-like molded bodies were sandwiched between one sheet of paper substrate (qualitative filter paper No. 2). A sheet-like laminate was prepared by overlapping two sides of a 0.26 mm thick material (manufactured by ADV ANTEC Co., Ltd.) and heating and pressurizing it for 2 minutes using a pressure molding machine (4-ton double-clamp hydraulic molding machine, manufactured by Iwaki Kogyo Co., Ltd.) heated to 100°C. Next, the sample was cut using a sample cutter (SDL200, manufactured by DUMBBELL Co., Ltd.) with a thickness of 0.26 mm, a width of 10 mm, and a length of 100 mm, thereby preparing a dumbbell-shaped sample (Comparative Example 7) containing a lignin-derived material.

[0411] 2. Sample Evaluation

[0412] For the samples of each embodiment and comparative example, the breaking strength, bending resistance and monolignin alcohol recovery were evaluated by the following methods.

[0413] <Fracturing Strength Evaluation>

[0414] Following JIS-C-2151 and ASTM-D-882, using TENSILON RTF-2410 (manufactured by A&D Corporation), dumbbell-shaped samples (Examples 1-46 and 49-51, and Comparative Examples 1-7) were stretched at a clamping interval of 50 mm and a speed of 200 mm / min. The paper substrate (qualitative filter paper No. 2) in each dumbbell-shaped sample was measured three times. The breaking strength of the paper substrate (0.26 mm thick, manufactured by ADVANTEC Co., Ltd.) when cut (breaks) and the breaking strength of the portion other than the paper substrate (represented as Examples 1-46, 49-51, and Comparative Examples 1-7) when cut (breaks) were averaged. Next, for the average breaking strength obtained, the rate of increase in breaking strength of Examples 1-46, 49-51, and Comparative Examples 1-7 relative to the breaking strength of the paper substrate only was calculated {(breaking strength of Examples 1-46, 49-51, and Comparative Examples 1-7 / breaking strength of the paper substrate only) × 100}, and the breaking strength was evaluated according to the following criteria.

[0415] ◎: The rate of increase in fracture strength is over 200%.

[0416] ○: The rate of increase in fracture strength is 100% or more but less than 200%.

[0417] △: The rate of increase in fracture strength is greater than 30% but less than 100%.

[0418] ×: The rate of increase in fracture strength is less than 30%.

[0419] <Evaluation of Elongation at Break>

[0420] The dumbbell-shaped samples (Examples 1-46 and 49-51 and Comparative Examples 1-7) were bent 180 degrees at the center and then bent using a stainless steel plate ( The sample (weighing 5 kg) was held for 30 seconds. After 30 seconds, the bend was released, and the bent portion of the sample was observed at 100x magnification using an optical microscope (BX53M, Olympus Corporation). The "bending-observation" process was repeated, and the number of bends until sample failure was measured. Each sample was tested three times, and the bending resistance was evaluated based on the average of the three tests according to the following criteria.

[0421] ◎: The sample did not break even after being bent 20 times.

[0422] ○: The sample breaks down due to bending more than 15 but less than 19 times.

[0423] △: The sample breaks down due to bending more than 5 times but less than 14 times.

[0424] ×: The sample breaks down due to bending less than 4 times.

[0425] <Evaluation of Monolignin Extraction Amount>

[0426] The weight of the lignocellulose used as raw material and the weight of the final recovered monolignin alcohol were determined using a precision balance TXC623N (manufactured by Shimadzu Corporation). The ratio {(weight of final recovered monolignin alcohol / weight of lignocellulose used) × 100} was calculated, and the monolignin alcohol extraction amount was evaluated according to the following criteria.

[0427] ○: The proportion is 7% or more.

[0428] △: The proportion is 5% or more but less than 7%.

[0429] ×: The proportion is less than 5%

[0430] 3. Evaluation results of the samples

[0431] (The effects of cellulose nanofibers (CNF) modification, the effects of CNF interaction with lignin-derived substances, and the effects of additives)

[0432] The results are shown in Table 1.

[0433] [Table 1]

[0434]

[0435] Table 1 shows that the complex of sulfated CNF-lignin-derived substances exhibits superior fracture strength and flexural strength compared to the complexes of carboxylated CNF-lignin-derived substances, phosphorylated CNF-lignin-derived substances, and unmodified CNF-lignin-derived substances. Furthermore, the complex of sulfated CNF-lignin-derived substances (crosslinked complex) shows superior fracture strength and flexural strength compared to the complex of sulfated CNF-lignin-derived substances (hydrogen-bonded complex). Additionally, the addition of additives such as polyethylene, PHBH, or natural rubber to the complexes of sulfated CNF-lignin-derived substances can further improve fracture strength and flexural strength.

[0436] (The effect of the CNF solids ratio and CNF fiber width in a complex of sulfated CNF-derived substances)

[0437] The results are shown in Table 2.

[0438] [Table 2]

[0439]

[0440] Table 2 shows that when the proportion of CNF solids in the sulfated CNF-lignin-derived substance composite exceeds 0.03 wt% and is less than 85 wt%, preferably 0.05 wt% to 80 wt%, it can further improve the breaking strength and flexural strength. Furthermore, it is found that the breaking strength decreases when the CNF fiber width exceeds 600 nm. This is believed to be because, with the increase of CNF fiber width, the specific surface area of ​​CNF decreases, thereby reducing the number of interaction points with the lignin-derived substance. Moreover, it is shown that even when the sulfated CNF has carboxyl, phosphate, or acetyl groups as other substituents besides the sulfate group, it still exhibits good breaking strength and flexural strength in the sulfated CNF-lignin-derived substance composite.

[0441] (The effect of the hybrid method)

[0442] The results are shown in Table 3.

[0443] [Table 3]

[0444]

[0445] As shown in Table 3, the preparation of the complex of sulfated CNF-lignin-derived substances is achieved by mixing with shear force applied by a three-roll mill and a twin-screw mixer, thereby achieving uniform dispersion and improving fracture strength and bending resistance.

[0446] The results of (the effects of reagents (c) and (e)) are shown in Table 4.

[0447] [Table 4]

[0448]

[0449] As shown in Table 4, reagent (c) can be formaldehyde (an aldehyde), acetone (a ketone), boric acid, 2-methoxypropene, dimethyl carbonate, or 2,2-dimethoxypropane; reagent (e) can be acetic anhydride or propionic anhydride. Furthermore, it is known that without reagent (e), aldehyde formation due to the Albright-Gorman oxidation reaction will not occur, the chemical equilibrium will not favor protection (acetalization), therefore the protection of lignin-derived substances will be insufficient, β-O-4 bonds will condense, and the extraction of monolignin alcohols will become incomplete.

[0450] (The effect of adding reagents and the effect when the reaction stops)

[0451] The results are shown in Table 5.

[0452] [Table 5]

[0453]

[0454] Table 5 shows that adding reagent (e) after reagents (a) to (d), adding reagent (e) in addition, or adding reagent (e) after adding reagents (a) to (d) and cooling can improve the flexural strength. Furthermore, it is shown that stopping the mixing (reaction) after the absorbance at 500 nm of the solution obtained by diluting the reaction solution 20 times to a value of 0.5 or higher can improve the extraction rate of monolignin alcohols.

[0455] (The effect of lignocellulose amount relative to the total amount in the reaction system)

[0456] The results are shown in Table 6.

[0457] [Table 6]

[0458]

[0459] As shown in Table 6, the extraction rate of monolignin alcohol can be improved by making the amount of lignocellulose relative to the total amount of the reaction system more than 4 parts by weight and less than 55 parts by weight, preferably 5 parts by weight to 50 parts by weight. This is believed to be because when the amount of lignocellulose relative to the total amount of the reaction system is less than 4 parts by weight, the yield is low, and when the amount of lignocellulose relative to the total amount of the reaction system is more than 55 parts by weight, the stirring efficiency decreases.

[0460] (The manufacturing effect of materials derived from lignocellulose)

[0461] The results are shown in Table 7.

[0462] [Table 7]

[0463]

[0464] As shown in Table 7, according to the present invention, it is possible to efficiently synthesize a complex of sulfated CNF-derived lignin-based substances, sulfated CNC, and monolignin alcohol.

[0465] All publications, patents and patent applications cited in this specification are incorporated herein by reference.

Claims

1. A composition comprising: Cellulose nanofibers with sulfate groups, and Substances derived from lignin The lignin-derived substances are selected from sulfate lignin, lignin sulfonic acid, soda lignin, soda anthraquinone lignin, sulfate lignin, diol lignin, enzymatically hydrolyzed lignin, hydrothermally treated lignin, steam explosion-treated lignin, organic solvent lignin, and their salts. The lignin-derived substances contain hydroxyl, aldehyde, carboxyl, methoxy, carbonyl, olefin, or ether groups. The cellulose nanofibers with sulfate groups and the lignin-derived substance form a composite, wherein the composite is a cross-linked composite formed by the cellulose nanofibers with sulfate groups and the lignin-derived substance, and the cross-linking is a chemical bond formed by a condensation or addition reaction between the hydroxyl groups of the cellulose nanofibers with sulfate groups and the aforementioned groups or sites of the lignin-derived substance.

2. The composition according to claim 1, wherein, The sulfate groups of the cellulose nanofibers having sulfate groups are represented by the chemical formula (1). [Chemical Formula 1] ， In the formula, M represents a cation with a valence of 1 to 3.

3. The composition according to claim 1, wherein, The crystallinity of the cellulose nanofibers with sulfate groups is 20%~99%.

4. The composition according to any one of claims 1 to 3, further comprising: At least one substance selected from resins and rubbers.

5. The composition according to any one of claims 1 to 3, further comprising: At least one type of packing material selected from organic and inorganic packing materials.

6. The composition according to any one of claims 1 to 3, wherein, The content of the cellulose nanofibers with sulfate groups is 0.03% to 85% by weight relative to the total weight of the composition.

7. The composition according to any one of claims 1 to 3, wherein, The content of the lignin-derived substance is 0.03% to 85% by weight relative to the total weight of the composition.

8. The composition according to any one of claims 1 to 3, wherein, The weight ratio of the sulfate-containing cellulose nanofibers to the lignin-derived substance (sulfate-containing cellulose nanofibers: lignin-derived substance) is 0.05:99.5 to 85.0:15.

0.

9. A method for manufacturing a material derived from lignocellulose, comprising: (A). A step of preparing a mixture by mixing (a) lignin content of 20% or more relative to the total weight of lignocellulose, (b) sulfuric acid, (c) at least one compound selected from aldehyde, ketone, boric acid, 2-methoxypropylene, dimethyl carbonate and 2,2-dimethoxypropane, (d) dimethyl sulfoxide as a solvent, and (e) at least one carboxylic anhydride selected from acetic anhydride and propionic anhydride, and reacting it to obtain the reactant; (B). A process of neutralizing the reactants obtained from step (A) with an alkali to obtain a neutralized product; (C). A process of separating the neutralized product obtained from step (B) into a first solid component and a first liquid component; (D). The first solid component obtained from step (C) is composed of cellulose with sulfate groups and a substance derived from lignin, and the cellulose with sulfate groups and the substance derived from lignin form a cross-linked composite. The composite is mixed with water or an organic solvent or a mixture thereof while applying shear force and then defibriled to obtain a composite containing cellulose nanofibers with sulfate groups and a substance derived from lignin. and (D'''). An ether solvent is added to the first liquid component obtained from step (C) to precipitate the lignin-derived substances. In step (A), after the solution of the reactants in (d), (b), (c), (a) and (e) is partially diluted by 20 times and the absorbance of the resulting solution at a wavelength of 500 nm reaches 0.5 or more, step (B) is carried out.

10. The method according to claim 9, wherein, In step (A), the proportion of lignocellulose in the mixture is 5% to 50% by weight relative to the total weight of the mixture.

11. The method according to claim 9 or 10, wherein, In process (A), (b), (c), (a) and (e) are added to (d) sequentially with a time difference.

12. The method according to claim 9 or 10, wherein, In step (A), add (b), (c), (a) and (e) to (d) in sequence, mix for more than 30 minutes to allow the reaction to proceed, and then add (e) to allow the reaction to proceed.

13. The method according to claim 9 or 10, wherein, In step (A), after adding (b), (c) and (a) to (d) in sequence, the mixture is heated to above 50°C while being mixed to allow it to react. Then, it is cooled to below 50°C, and (e) is added to allow it to react.

14. A composite comprising: cellulose nanofibers having sulfate groups and a lignin-derived substance, The cellulose nanofibers with sulfate groups interact with the lignin-derived substance. The lignin-derived substances are selected from sulfate lignin, lignin sulfonic acid, soda lignin, soda anthraquinone lignin, sulfate lignin, diol lignin, enzymatically hydrolyzed lignin, hydrothermally treated lignin, steam explosion-treated lignin, organic solvent lignin, and their salts. The lignin-derived substances contain hydroxyl, aldehyde, carboxyl, methoxy, carbonyl, olefin, or ether groups. The cellulose nanofibers with sulfate groups are cross-linked with the lignin-derived substance. The cross-linking is a chemical bond formed by a condensation or addition reaction between the hydroxyl groups of the cellulose nanofibers with sulfate groups and the aforementioned groups or sites of the lignin-derived substance.

15. The composite according to claim 14, wherein, The crystallinity of the cellulose nanofibers with sulfate groups is 20%~99%.

16. The composite according to claim 14 or 15, wherein, The weight ratio of the sulfate-containing cellulose nanofibers to the lignin-derived substance (sulfate-containing cellulose nanofibers: lignin-derived substance) is 0.05:99.5 to 85.0:15.0.

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