resin composition

Abstract

In one embodiment, the present invention provides a resin composition and a method for producing the same, as well as a molded article obtained by molding the resin composition, which exhibits the advantageous properties inherent in styrene-based elastomers (good rubber elasticity, weather resistance, chemical resistance, etc.), while also being excellent in tensile strength, tensile modulus, and / or tensile elongation at break, and further exhibiting fewer undesirable properties such as whitening and discoloration. [Solution] In one embodiment, a resin composition comprising a thermoplastic elastomer and cellulose nanofibers is provided, wherein the thermoplastic elastomer comprises an acid-modified styrene elastomer and a styrene elastomer, and the amount of the thermoplastic elastomer is 60% by mass or more of 100% by mass of the resin composition.

Description

[Technical Field]

[0001] The present invention relates to a resin composition containing a styrene-based elastomer. [Background technology]

[0002] Thermoplastic elastomers have been used in a wide range of applications because they exhibit rubber elasticity while being melt-molded using the same methods as thermoplastic resins. Known thermoplastic elastomers include styrene-based, olefin-based, polyurethane-based, polyester-based, polyamide-based, acrylic-based, and polyvinyl chloride-based types. Of these, styrene-based elastomers, due to their excellent weather resistance and chemical resistance, have been used in sealing materials, as well as modifiers and additives for various materials.

[0003] In resin molded articles, it is necessary to achieve a high degree of balance between various properties desired depending on the application, such as mechanical strength, flexibility, wear resistance, and processability. To improve these properties, it is common practice to include fillers in the resin molded articles. In recent years, with growing awareness of environmental issues, the use of cellulose, a low-density and renewable material, as a filler to be included in resin molded articles has been explored in various ways. Among these, cellulose nanofibers are particularly promising as a filler for resin molded articles because they provide a good reinforcing effect per unit of material used when combined with various resins to construct the resin molded article.

[0004] Patent Document 1 describes a resin composition comprising a polyamide, an elastomer, and cellulose, wherein at least a portion of the elastomer has an acidic functional group, the polyamide and the elastomer are phase-separated, and more than 50% by mass of the cellulose is present in the polyamide phase. Patent Document 2 describes a resin composition comprising a polyamide, one or more elastomers selected from the group consisting of aromatic vinyl compound-conjugated diene compound block copolymers and derivatives thereof, and cellulose, wherein the polyamide and the elastomers are phase-separated, and more than 50% by mass of the cellulose is present in the polyamide phase. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-029488 [Patent Document 2] Japanese Patent Publication No. 2022-007985 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] Among resin molded articles, those primarily composed of styrene-based elastomers, for example, are promising because they exhibit good rubber elasticity and excellent weather resistance and chemical resistance. If styrene-based elastomers can be combined with cellulose nanofibers, in addition to the properties inherent in styrene-based elastomers, properties such as good tensile strength, tensile modulus, and tensile elongation at break can also be imparted. However, since styrene-based elastomers are inherently hydrophobic, while cellulose nanofibers are inherently hydrophilic due to the presence of hydroxyl groups, they tend to be difficult to mix with each other. If the mixing of styrene-based elastomers and cellulose nanofibers in a resin composition is poor, the molded article formed from that resin composition will not exhibit the desired physical properties, and when an external force is applied to the molded article, voids may form between the styrene-based elastomers and cellulose nanofibers, causing the molded article to whiten. On the other hand, if thorough melt mixing of styrene-based elastomers and cellulose nanofibers is performed to improve mixing, thermal degradation of the cellulose nanofibers (e.g., discoloration) may occur. The technologies described in Patent Documents 1 and 2 involve dispersing cellulose in polyamide while coexisting with a styrene-based elastomer. However, they do not focus on resin molded articles mainly composed of styrene-based elastomers, and therefore do not address the above-mentioned problems related to the combination of styrene-based elastomers and cellulose nanofibers.

[0007] One aspect of the present invention aims to solve the above problems and provide a resin composition, a method for producing the same, and a molded article made by molding the resin composition, which can form a resin molded article that exhibits the advantageous properties inherent in styrene-based elastomers (good rubber elasticity, weather resistance, chemical resistance, etc.), while also being excellent in tensile strength, tensile modulus, and / or tensile elongation at break, and further exhibiting fewer undesirable conditions such as whitening and discoloration.

[0008] Furthermore, for a resin molded article containing fillers to exhibit desired properties, it is sometimes important that the fillers are well dispersed in the resin. However, since cellulose is generally hydrophilic due to its hydroxyl groups, it has been proposed to use styrene-based elastomers as additives to well disperse cellulose in polymers.

[0009] Because styrene elastomers are flexible and have excellent weather resistance and chemical resistance, molded articles using styrene elastomers as the main polymer component are desired. However, conventionally, there have been limitations on the applications of resin molded articles using styrene elastomers as the main polymer component. Styrene elastomers generally exhibit tackiness (initial adhesion). For this reason, melt molding of styrene elastomers alone is difficult, and styrene elastomer molded articles tend to stick together, resulting in problems with processability and handling. The technology described in Patent Document 2 attempts to simultaneously achieve the conflicting properties of high toughness and low thermal expansion by using the above-mentioned elastomer in a resin composition containing polyamide and cellulose, but it does not provide a molded article using styrene elastomers as the main polymer component.

[0010] Therefore, another aspect of the present invention aims to solve the above problems and provide a resin composition and a method for producing the same, which can form a resin molded article that exhibits the excellent properties inherent in styrene-based elastomers (especially good rubber elasticity, weather resistance, chemical resistance, etc.) while also being excellent in processability and handling, as well as a resin molded article formed by molding the resin composition. [Means for solving the problem]

[0011] This disclosure includes the following items: [Item 1] A resin composition comprising a thermoplastic elastomer and cellulose nanofibers, The thermoplastic elastomer comprises an acid-modified styrene elastomer and a styrene elastomer. A resin composition in which the amount of the thermoplastic elastomer is 60% by mass or more of the resin composition by 100% by mass. [Item 2] A resin composition comprising a thermoplastic elastomer and cellulose nanofibers, The number-average aspect ratio, which is the ratio L / D of the number-average fiber length L to the number-average fiber diameter D of the cellulose nanofibers in the resin composition, is 2 or more and 26 or less. A resin composition in which the amount of the thermoplastic elastomer is 60% by mass or more of the resin composition by 100% by mass. [Item 3] A resin composition comprising a thermoplastic elastomer and cellulose nanofibers, When the cellulose nanofibers were separated from the resin composition using tetrahydrofuran (THF), the weight increase rate of the cellulose nanofibers was 190% to 600%. A resin composition in which the amount of the thermoplastic elastomer is 60% by mass or more of the resin composition by 100% by mass. [Item 4] The resin composition includes, as the thermoplastic elastomer, an acid-modified styrene elastomer and a styrene elastomer. The resin composition according to any one of items 1 to 3, wherein the total amount of the acid-modified styrene elastomer and the styrene elastomer is 60% by mass or more of the resin composition as described above. [Item 5] The resin composition includes, as the thermoplastic elastomer, an acid-modified styrene elastomer and a styrene elastomer. The resin composition according to any one of items 1 to 4, wherein the acid-modified styrene elastomer and the styrene elastomer are compatible. [Item 6] The resin composition includes, as the thermoplastic elastomer, an acid-modified styrene elastomer and a styrene elastomer. The resin composition according to any one of items 1 to 5, wherein the amount of the acid-modified styrene elastomer is 0.5 to 50 parts by mass per 100 parts by mass of the styrene elastomer. [Item 7] The resin composition includes a styrene-based elastomer as the thermoplastic elastomer, The resin composition according to any one of items 1 to 6, wherein the amount of the styrene-based elastomer is 0.5 parts by mass to 250 parts by mass per 1 part by mass of the cellulose nanofiber. [Item 8] The resin composition includes an acid-modified styrene-based elastomer as the thermoplastic elastomer. The resin composition according to any one of items 1 to 7, wherein the amount of the acid-modified styrene elastomer is 0.5 to 45 parts by mass per 1 part by mass of the cellulose nanofiber. [Item 9] The resin composition includes an acid-modified styrene-based elastomer as the thermoplastic elastomer. The resin composition according to any one of items 1 to 8, wherein the amount of the acid-modified styrene elastomer is 0.5% to 50% by mass in 100% by mass of the resin composition. [Item 10] The resin composition includes a styrene-based elastomer as the thermoplastic elastomer, The resin composition according to any one of items 1 to 9, wherein the amount of the styrene-based elastomer in 100% by mass of the resin composition is 10% by mass to 98.8% by mass. [Item 11] A resin composition according to any one of items 1 to 10, comprising 0.1% to 20% by mass of the cellulose nanofibers. [Item 12] The resin composition includes an acid-modified styrene-based elastomer as the thermoplastic elastomer. The resin composition according to any one of items 1 to 11, wherein the acid modification rate of the acid-modified styrene-based elastomer is 0.2% by mass to 2.5% by mass. [Item 13] The resin composition includes a styrene-based elastomer as the thermoplastic elastomer, The resin composition according to any one of items 1 to 12, wherein the styrene-based elastomer is an unmodified product. [Item 14] The resin composition includes an acid-modified styrene-based elastomer as the thermoplastic elastomer. The resin composition according to any one of items 1 to 13, wherein the acid-modified styrene elastomer is an acid-modified product of a styrene elastomer that is an aromatic vinyl compound-conjugated diene compound block copolymer or a hydrogenated thereof. [Item 15] The resin composition includes a styrene-based elastomer as the thermoplastic elastomer, The resin composition according to any one of items 1 to 14, wherein the styrene-based elastomer is an aromatic vinyl compound-conjugated diene compound block copolymer or a hydrogenated thereof. [Item 16] The resin composition includes a styrene-based elastomer as the thermoplastic elastomer, The resin composition according to any one of items 1 to 15, wherein the melt mass flow rate of the styrene-based elastomer at 230°C and 2.16 kg is 20 g / 10 min or less. [Item 17] The resin composition includes an acid-modified styrene-based elastomer as the thermoplastic elastomer. The resin composition according to any one of items 1 to 16, wherein the styrene unit ratio of the acid-modified styrene elastomer is 10% by mass to 45% by mass. [Item 18] The resin composition includes a styrene-based elastomer as the thermoplastic elastomer, The resin composition according to any one of items 1 to 17, wherein the styrene unit ratio of the styrene-based elastomer is 10% to 45% by mass. [Item 19] The resin composition includes, as the thermoplastic elastomer, an acid-modified styrene elastomer and a styrene elastomer. The resin composition according to any one of items 1 to 18, wherein the ratio of the styrene unit ratio of the styrene-based elastomer to the styrene unit ratio of the acid-modified styrene-based elastomer (styrene ratio of the styrene-based elastomer / styrene ratio of the acid-modified styrene-based elastomer) is 0.3 to 2.5. [Item 20] The resin composition includes, as the thermoplastic elastomer, an acid-modified styrene elastomer and a styrene elastomer. The resin composition according to any one of items 1 to 19, wherein the number average molecular weight of the acid-modified styrene elastomer is 10,000 to 500,000, and the number average molecular weight of the styrene elastomer is 10,000 to 500,000. [Item 21] The resin composition includes an acid-modified styrene-based elastomer as the thermoplastic elastomer. The resin composition according to any one of items 1 to 20, wherein the ratio of the styrene unit ratio to the acid modification rate (styrene unit ratio / acid modification rate) in the acid-modified styrene elastomer is 5 to 90. [Item 22] The resin composition includes an acid-modified styrene-based elastomer as the thermoplastic elastomer. The resin composition according to any one of items 1 to 21, wherein the amount of acid-modified groups of the acid-modified styrene elastomer is 0.2% to 5.0% by mass, relative to 100% by mass of the cellulose nanofibers. [Item 23] The resin composition according to any one of items 1 to 22, wherein the number-average fiber diameter of the cellulose nanofibers is 2 nm to 1000 nm. [Item 24] The resin composition according to any one of items 1 to 23, wherein the thermal decomposition initiation temperature of the cellulose nanofiber is 250°C or higher. [Item 25] The specific surface area of ​​the cellulose nanofiber is 10 m². 2 / g~200m 2 A resin composition according to any one of items 1 to 24, which is / g. [Item 26] A resin composition according to any one of items 1 to 25, further comprising a polyoxyethylene unit-containing polymer. [Item 27] A resin composition according to any one of items 1 to 26, further comprising a liquid polymer. [Item 28] A method for producing a resin composition as described in any one of items 1 to 27, The resin composition includes, as the thermoplastic elastomer, an acid-modified styrene elastomer and a styrene elastomer. A method comprising heating and kneading a mixture containing the acid-modified styrene-based elastomer, the styrene-based elastomer, and the cellulose nanofiber. [Item 29] The method according to item 28, wherein the weight increase rate of the cellulose nanofibers after heating and kneading compared to the cellulose nanofibers before heating and kneading is 190% to 600%. [Item 30] A resin molded article obtained by molding a resin composition described in any one of items 1 to 27. [Item 31] A resin molded product as described in item 30, which is a deformed extruded product. [Item 32] A method for manufacturing a deformed extruded product, A method comprising the step of extruding a resin composition described in any one of items 1 to 27 into a deformed shape. [Item 33] A 3D printing material comprising a resin composition described in any one of items 1 to 27. [Item 34] A 3D printing material as described in item 33, having the form of a filament or powder. [Item 35] A molded object produced by 3D printing a resin composition described in any one of items 1 to 27. [Item 36] A 3D object formed by 3D printing using the 3D printing material described in item 33 or 34. [Item 37] A method for manufacturing a molded object, A method comprising the step of fabricating a resin composition described in any one of items 1 to 27 using a 3D printer. [Item 38] A method for manufacturing a molded object, A method comprising the step of fabricating a 3D printing material described in item 33 or 34 using a 3D printer. [Item 39] A resin composition comprising a styrene-based elastomer and a tack inhibitor containing cellulose nanofibers. [Effects of the Invention]

[0012] According to one aspect of the present invention, a resin composition and a method for producing the same, as well as a molded article obtained by molding the resin composition, are provided, which can form a resin molded article that exhibits the advantageous properties inherent in styrene-based elastomers (good rubber elasticity, weather resistance, chemical resistance, etc.), while also being excellent in tensile strength, tensile modulus, and / or tensile elongation at break, and further exhibiting fewer undesirable conditions such as whitening and discoloration.

[0013] According to another aspect of the present invention, a resin composition and a method for producing the same can be provided, which can form a resin molded article that exhibits the excellent properties inherent in styrene-based elastomers (especially good rubber elasticity, weather resistance, chemical resistance, etc.) while also having excellent processability and handling properties, as well as a resin molded article obtained by molding the resin composition. [Modes for carrying out the invention]

[0014] The following describes exemplary embodiments of the present invention (hereinafter also referred to as "these embodiments"), but the present invention is not limited to these embodiments, and various modifications are possible within the scope of its gist.

[0015] ≪Resin composition≫ One aspect of the present invention provides a resin composition comprising a thermoplastic elastomer and cellulose nanofibers. In one aspect, the amount of thermoplastic elastomer is 60% by mass or more in 100% by mass of the resin composition. In one aspect, the thermoplastic elastomer comprises a styrene-based elastomer, in one aspect, an acid-modified styrene-based elastomer, in one aspect, a styrene-based elastomer and an acid-modified styrene-based elastomer, and in one aspect, a styrene-based elastomer and an acid-modified styrene-based elastomer. In one embodiment, the number-average aspect ratio, which is the ratio L / D of the number-average fiber length L to the number-average fiber diameter D of cellulose nanofibers in the resin composition, is between 2 and 26. In one embodiment, the weight increase rate of cellulose nanofibers when cellulose nanofibers are separated from a resin composition using tetrahydrofuran (THF) is 190% to 600%.

[0016] One aspect of the present invention provides a resin composition comprising an acid-modified styrene elastomer, a styrene elastomer, and cellulose nanofibers. In the resin composition according to one aspect, the acid-modified styrene elastomer and the styrene elastomer are miscible without phase separation and are in a continuous phase. In one aspect, the total amount of the acid-modified styrene elastomer and the styrene elastomer is 60% by mass or more of 100% by mass of the resin composition. The styrene elastomer portion in the resin composition contributes to the expression of the good properties inherent in the styrene elastomer, while the acid-modified styrene elastomer portion in the resin composition interposes between the styrene elastomer and the cellulose nanofibers due to its good affinity with both, contributing to the reduction of problems caused by their poor affinity (for example, void generation due to delamination between them).

[0017] In one embodiment of the resin composition, it was found that the presence of cellulose nanofibers and an acid-modified styrene elastomer can reduce fuzzing during extrusion molding. As a result, the molded article can exhibit good surface smoothness. The reason why cellulose nanofibers and acid-modified styrene elastomers are excellent at reducing fuzzing is not clear, but it is possible that the cellulose nanofibers and acid-modified styrene elastomers bond through a reaction, and this modifies the surface of the styrene elastomer during molding, resulting in a smoothing effect. Furthermore, adding cellulose nanofibers to the styrene elastomer may also be advantageous in reducing shrinkage during molding, as well as improving the tensile strength, tensile modulus, tensile elongation at break, and / or hardness of the molded article. In one embodiment of the resin composition, it was found that the presence of an acid-modified styrene elastomer in addition to cellulose nanofibers can further improve the tensile strength, tensile modulus, tensile elongation at break, and / or hardness of the molded article, and reduce undesirable conditions such as whitening and discoloration of the molded article. Although not bound by theory, it is believed that the reaction between the hydroxyl groups of cellulose nanofibers and the acid-modified groups of the acid-modified styrene elastomer strengthens the interface between them, making it less likely for delamination to occur between the styrene elastomer, cellulose nanofibers, and acid-modified styrene elastomer when external force is applied to the molded body, and also making it less likely for discoloration to occur due to thermal degradation of the cellulose nanofibers. As a result, the property-improving effect of cellulose nanofibers is well exhibited, the generation of voids in the molded body due to delamination is suppressed, whitening is reduced, and discoloration of the cellulose nanofibers is also suppressed. The resin composition according to one embodiment is excellent in processability and handling while using a styrene elastomer that is excellent in rubber elasticity, weather resistance, chemical resistance, etc., and the property-improving effect of cellulose nanofibers is well exhibited, and furthermore, there are fewer disadvantages such as whitening and discoloration, making it suitable as a substitute for thermoplastic polyurethane elastomer (TPU), for example.

[0018] One aspect of the present invention also provides a resin composition comprising a styrene elastomer and a tack inhibitor containing cellulose nanofibers. Styrene elastomers inherently possess good rubber elasticity, weather resistance, chemical resistance, etc., but due to their tackiness, they tend to be difficult to mold and the molded articles are difficult to handle. For example, molding materials with tackiness are difficult to separate from the mold during molding, and if strong force is applied to the molded article to remove it from the mold, it deforms and breaks, making it difficult to obtain a good molded article. Furthermore, when storing molded articles such as pellets, bales, injection molded articles, films, sheets, and filaments with tackiness, the contact points between the molded articles block each other, creating a situation where handling is difficult in all processes. In the resin composition according to one aspect, it has been found that the presence of cellulose nanofibers suppresses tackiness, making molding easier and the molded articles easier to handle. The cellulose nanofibers according to one aspect can function as a tack inhibitor either alone or in cooperation with other components in the resin composition. The reason why cellulose nanofibers are superior in reducing the tack of styrene-based elastomers is not entirely clear, but it is possible that the fine fibrous structure of cellulose nanofibers contributes to their superior physical entanglement with styrene-based elastomers compared to other fillers (e.g., silica particles, glass fibers, carbon fibers), resulting in a good tack reduction effect. Cellulose nanofibers are also advantageous because they are softer than, for example, silica particles, glass fibers, and carbon fibers, so they do not impair the rubber elasticity inherent in styrene-based elastomers. Furthermore, adding cellulose nanofibers to styrene-based elastomers may also be advantageous in reducing shrinkage during molding and improving the tensile strength, tensile modulus, tensile elongation at break, and / or hardness of the molded article. The resin composition according to one embodiment is useful as a soft resin molded article because it has suppressed tackiness and excellent processability and handling properties, even while using a styrene-based elastomer, and is suitable as, for example, a substitute for thermoplastic polyurethane elastomer (TPU).

[0019] The tack strength of the resin composition according to one aspect at 23°C, a load of 600 gf, a pressing time of 60 seconds, and a peeling speed of 600 mm / min measured by the probe tack test (hereinafter sometimes simply referred to as tack strength) is 10.0 gf / mm 2 or less. In one aspect, the above tack strength is 9.0 gf / mm 2 or less, or 7.0 gf / mm 2 or less, or 5.0 gf / mm 2 or less, or 3.0 gf / mm 2 or less, or 2.0 gf / mm 2 or less, or 1.5 gf / mm 2 or less, or 1.0 gf / mm 2 or less. In one aspect, from the perspective of the ease of manufacturing the resin composition, the above tack strength is 0.001 gf / mm 2 or more, or 0.01 gf / mm 2 or more, or 0.1 gf / mm 2 or more, or 0.3 gf / mm 2 or more, or 0.5 gf / mm 2 or more.

[0020] The tack strength of the resin composition according to one aspect is preferably 70% or less, or 60% or less, or 50% or less, or 40% or less, or 30% or less, or 25% or less, or 20% or less, or 15% or less, or 10% or less with respect to 100% of the tack strength of a resin composition having the same composition except for not containing cellulose nanofibers. Although it is desirable that the above ratio is small from the perspective of tack suppression, in one aspect, from the perspective of the ease of manufacturing the resin composition, it may be 0.0001% or more, or 0.1% or more, or 1% or more, or 3% or more. It is also preferable that the tack strength of the resin composition according to one aspect shows the above-exemplified ratio with respect to 100% of the tack strength of the styrene-based elastomer contained in the resin composition.

[0021] The components of the resin composition will be described below. In this embodiment, the amounts of each component described as values ​​in the resin composition may be considered as the amounts of each component in the resin composition, and the amounts of each component described as values ​​in the resin composition may be considered as the amounts of each component in the resin composition.

[0022] <Cellulose nanofiber> Cellulose nanofibers are fibers obtained by finely processing cellulose fiber raw materials through methods such as defibration treatment. Natural cellulose and regenerated cellulose can be used as cellulose fiber raw materials. As natural cellulose, wood pulp obtained from wood species (hardwood or softwood), non-wood pulp obtained from non-wood species (cotton, bamboo, hemp, bagasse, kenaf, cotton linter, sisal, straw, etc.), and cellulose fiber aggregates produced by animals (e.g., sea squirts), algae, and microorganisms (e.g., acetic acid bacteria) can be used. As regenerated cellulose, regenerated cellulose fibers (viscose, cupro, Tencel, etc.), cellulose derivative fibers, and ultrafine threads of regenerated cellulose or cellulose derivatives obtained by electrospinning can be used. Cellulose fiber raw materials that give cellulose nanofibers with a fuzzy surface may be advantageous in terms of tack suppression effect. From this viewpoint, cotton linter and the like are preferred cellulose fiber raw materials.

[0023] In one embodiment, defibration is a dry or wet mechanical treatment, preferably a wet treatment in which a slurry obtained by dispersing cellulose fiber raw material in a liquid medium is subjected to mechanical treatment. A single apparatus may be used for defibration once or more times, or multiple apparatuses may be used, each once or more times. The apparatus used for defibration is not particularly limited, but examples include high-speed rotary type, colloid mill type, high-pressure type, roll mill type, ultrasonic type, and high-pressure or ultra-high-pressure homogenizers, refiners, beaters, PFI mills, kneaders, dispersers, high-speed defibration machines, grinders (stone mill type pulverizers), ball mills, vibratory mills, bead mills, conical refiners, disc refiners, single-screw, twin-screw or multi-screw kneaders and extruders.

[0024] Cellulose fiber raw materials may be subjected to pretreatment before defibration. Pretreatment can be used to adjust the fiber diameter, fiber length, degree of fibrillation, etc., as well as to adjust the content of components other than cellulose (acid-insoluble components such as lignin, alkali-soluble polysaccharides such as hemicellulose, etc.), molecular weight, degree of crystallinity, etc.

[0025] In one embodiment, the pretreatment may be one or more selected from chemical treatment, pulverization, grinding, and classification. Chemical treatment is a treatment using chemicals, such as pulverization, bleaching, purification, hydrolysis, enzymatic treatment, regeneration celluloseization, and chemical modification. Pulverization is a dry pulverization of the cellulose fiber raw material. Grinding is a wet pulverization of a slurry obtained by dispersing the cellulose fiber raw material in a liquid medium. Classification is a separation operation to standardize the fiber length of the cellulose fiber raw material, and may be dry classification or wet classification.

[0026] Examples of the liquid medium include water and / or other media (e.g., organic solvents, inorganic acids, bases and / or ionic liquids), and may contain one or more types of media.

[0027] Commonly used organic solvents include, for example: alcohols (e.g., methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, s-butanol, t-butanol, ethylene glycol, diethylene glycol, glycerin, etc.); ethers (e.g., propylene glycol monomethyl ether, 1,2-dimethoxyethane, diisopropyl ether, tetrahydrofuran, 1,4-dioxane, etc.); carboxylic acids (e.g., formic acid, acetic acid, lactic acid, etc.); esters (e.g., ethyl acetate, vinyl acetate, etc.); ketones (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, etc.); nitrogen-containing solvents (e.g., dimethylformamide, dimethylacetamide, acetonitrile, etc.); and sulfur-containing solvents (dimethyl sulfoxide). In a typical embodiment, the liquid medium in the slurry is substantially water only.

[0028] In one embodiment, the number-average fiber length L of the cellulose nanofibers is preferably 100 nm or more, or 500 nm or more, 1 μm or more, or 5 μm or more, or 10 μm or more, or 20 μm or more, from the viewpoint of exhibiting a good effect of improving physical properties by the cellulose nanofibers, and preferably 1000 μm or less, or 800 μm or less, or 500 μm or less, or 400 μm or less, or 300 μm or less, or 200 μm or less, from the viewpoint of good dispersion of the cellulose nanofibers in the resin composition.

[0029] In one embodiment, the number-average fiber diameter D of the cellulose nanofibers is preferably 2 to 1000 nm from the viewpoint of obtaining a good effect of improving physical properties by the cellulose nanofibers. More preferably, the number-average fiber diameter of the cellulose nanofibers is 4 nm or more, or 5 nm or more, or 10 nm or more, or 15 nm or more, or 20 nm or more, and more preferably 900 nm or less, or 800 nm or less, or 700 nm or less, or 600 nm or less, or 500 nm or less, or 400 nm or less, or 300 nm or less, or 200 nm or less.

[0030] The average fiber length (L) / fiber diameter (D) ratio of cellulose nanofibers is preferably 30 or more, or 50 or more, or 80 or more, or 100 or more, or 120 or more, or 150 or more, from the viewpoint of effectively improving the mechanical properties of the rubber composite containing cellulose nanofibers with a small amount of cellulose nanofibers. There is no particular upper limit, but from the viewpoint of ease of handling, it is preferably 5000 or less, or 3000 or less, or 2000 or less, or 1000 or less.

[0031] In this disclosure, the fiber length, fiber diameter, and L / D ratio of cellulose nanofibers are values ​​measured using a scanning electron microscope (SEM) by the following procedure. An aqueous dispersion of cellulose nanofibers is replaced with tert-butanol and diluted to 0.001-0.1% by mass. The dispersion is then dispersed using a high-shear homogenizer (e.g., IKA product, trade name "Ultra-Turrax T18") under the following conditions: rotation speed 15,000 rpm for 3 minutes. The sample is cast onto an osmium-deposited silicon substrate and air-dried. This sample is then measured using a high-resolution scanning electron microscope (SEM). Specifically, the length (L) and diameter (D) of 100 randomly selected cellulose nanofibers are measured in an observation field adjusted to the magnification so that at least 100 cellulose nanofibers are observed, and the ratio (L / D) is calculated. The number average values ​​of these are then used as the number average fiber diameter L and number average fiber diameter D, and the ratio (L / D) is calculated.

[0032] The number-average aspect ratio, which is the ratio L / D of the number-average fiber length L to the number-average fiber diameter D of the cellulose nanofibers in the resin composition, is in one embodiment between 2 and 26. The upper limit of the aspect ratio is not particularly limited, but is preferably 25 or less from the viewpoint of handling. The lower limit of the aspect ratio is not particularly limited, but is preferably 5 or more, or 10 or more, or 15 or more. The aspect ratio is a value measured by the method described in the [Examples] section of this disclosure.

[0033] Known crystalline forms of cellulose include Type I, Type II, Type III, and Type IV. Among these, Type I and Type II are particularly widely used, while Type III and Type IV, although obtained on a laboratory scale, are not widely used on an industrial scale. The cellulose nanofibers of this disclosure have relatively high structural mobility, and by dispersing these cellulose nanofibers in rubber, a molded article with a lower coefficient of thermal expansion and superior strength and elongation during tensile and bending deformation can be obtained. Therefore, cellulose nanofibers containing cellulose Type I crystals or cellulose Type II crystals are preferred, and cellulose nanofibers containing cellulose Type I crystals and having a crystallinity of 55% or higher are more preferred.

[0034] The crystallinity of the cellulose nanofibers is preferably 55% or higher. The higher the crystallinity, the higher the mechanical properties (strength, dimensional stability) of the cellulose itself, and therefore, when cellulose nanofibers are dispersed in rubber, the rubber composite tends to have higher strength and dimensional stability. A more preferable lower limit for the crystallinity is 60%, even more preferably 70%, and most preferably 80%. There is no particular upper limit for the crystallinity of the cellulose nanofibers, and a higher value is preferable, but from a production standpoint, a preferable upper limit is 99%.

[0035] The degree of crystallinity referred to here, when the cellulose nanofiber is a type I cellulose crystal (derived from natural cellulose), can be determined by the Segal method from the diffraction pattern (2θ / deg. of 10 to 30) obtained by measuring the sample by wide-angle X-ray diffraction, using the following formula. Crystallinity (%)=[I (200) -I (amorphous) ] / I (200) ×100 I (200) :Diffraction peak intensity at the 200 plane (2θ=22.5°) in cellulose type I crystals I (amorphous) : The halo peak intensity due to amorphous material in type I cellulose crystals, specifically the peak intensity at an angle 4.5° lower than the diffraction angle of the 200 plane (2θ = 18.0°).

[0036] Furthermore, if the cellulose is a type II cellulose crystal (derived from regenerated cellulose), the degree of crystallinity can be determined by the following formula using wide-angle X-ray diffraction, based on the absolute peak intensity h0 at 2θ=12.6°, which is attributed to the (110) plane peak of the type II cellulose crystal, and the baseline peak intensity h1 at this interplanar spacing (the line connecting 2θ=8° and 15°). Crystallinity (%) = (h0-h1) / h0 ×100

[0037] Furthermore, the degree of polymerization of the cellulose nanofiber is preferably 100 or higher, more preferably 150 or higher, more preferably 200 or higher, more preferably 300 or higher, more preferably 400 or higher, more preferably 450 or higher, preferably 3500 or lower, more preferably 3300 or lower, more preferably 3200 or lower, more preferably 3100 or lower, and more preferably 3000 or lower.

[0038] From the viewpoint of processability and mechanical property development, it is desirable to keep the degree of polymerization of cellulose nanofibers within the above-mentioned range. From the viewpoint of processability, it is preferable that the degree of polymerization is not too high, and from the viewpoint of mechanical property development, it is desirable that it is not too low.

[0039] The degree of polymerization of cellulose nanofibers refers to the average degree of polymerization measured according to the reduction ratio viscosity method using copper ethylenediamine solution, as described in the confirmation test (3) of the "Fifteenth Revised Japanese Pharmacopoeia Commentary (published by Hirokawa Shoten)".

[0040] In one embodiment, the weight-average molecular weight (Mw) of the cellulose nanofiber is 100,000 or more, more preferably 200,000 or more. The ratio of weight-average molecular weight to number-average molecular weight (Mn) (Mw / Mn) is 6 or less, preferably 5.6 or less, or 5.4 or less. A larger weight-average molecular weight means fewer end groups in the cellulose molecule. Furthermore, since the ratio of weight-average molecular weight to number-average molecular weight (Mw / Mn) represents the width of the molecular weight distribution, a smaller Mw / Mn means fewer end groups in the cellulose molecule. Since the end groups of cellulose molecules are the starting points for thermal decomposition, when the weight-average molecular weight of the cellulose nanofiber is large, and at the same time the width of the molecular weight distribution is narrow, particularly heat-resistant cellulose nanofibers and resin compositions containing cellulose nanofibers can be obtained. From the viewpoint of the availability of cellulose raw materials, the weight-average molecular weight (Mw) of the cellulose nanofiber may be, for example, 600,000 or less, or 500,000 or less, or 400,000 or less. The number-average molecular weight (Mn) of cellulose nanofibers may be, for example, 200,000 or less, 150,000 or less, 100,000 or less, 80,000 or less, or 60,000 or less, from the viewpoint of the availability of cellulose fiber raw materials. The ratio of weight-average molecular weight to number-average molecular weight (Mn) (Mw / Mn) may be, for example, 1.5 or more, 1.7 or more, or 2 or more, from the viewpoint of the ease of manufacturing cellulose nanofibers. Mw can be controlled to the above range by selecting a cellulose raw material having an Mw appropriate for the purpose, and by appropriately performing physical and / or chemical treatments on the cellulose raw material within an appropriate range. Mw / Mn can also be controlled to the above range by selecting a cellulose raw material having an Mw / Mn appropriate for the purpose, and by appropriately performing physical and / or chemical treatments on the cellulose raw material within an appropriate range. In one embodiment, each of the Mw and Mw / Mn of the cellulose raw material may be within the above range.

[0041] The weight-average molecular weight and number-average molecular weight of cellulose nanofibers referred to herein are values ​​obtained by dissolving cellulose nanofibers in N,N-dimethylacetamide to which lithium chloride has been added, and then determining them by gel permeation chromatography using N,N-dimethylacetamide as the solvent.

[0042] The alkali-soluble polysaccharides that cellulose nanofibers may contain include not only hemicellulose but also β-cellulose and γ-cellulose. Alkali-soluble polysaccharides are understood by those skilled in the art to be components obtained as the alkali-soluble part of holocellulose obtained by solvent extraction and chlorine treatment of plants (e.g., wood) (i.e., components obtained by removing α-cellulose from holocellulose). Since alkali-soluble polysaccharides are polysaccharides containing hydroxyl groups and have poor heat resistance, they can cause problems such as decomposition when heated, yellowing during thermal aging, and a decrease in the strength of cellulose nanofibers. Therefore, it is preferable to have a low alkali-soluble polysaccharide content in cellulose nanofibers.

[0043] In one embodiment, the average content of alkali-soluble polysaccharides in cellulose nanofibers is preferably 20% by mass or less, 18% by mass or less, 15% by mass or less, or 12% by mass or less, based on 100% by mass of cellulose nanofibers, from the viewpoint of obtaining good dispersibility of cellulose nanofibers. The above content may be 1% by mass or more, 2% by mass or more, or 3% by mass or more, from the viewpoint of ease of manufacturing cellulose nanofibers.

[0044] The average alkali-soluble polysaccharide content can be determined using the method described in non-patent literature (Wood Science Experiment Manual, edited by the Japan Wood Research Society, pp. 92-97, 2000), by subtracting the α-cellulose content from the holocellulose content (Wise method). This method is understood in this industry as a method for measuring hemicellulose content. The alkali-soluble polysaccharide content is calculated three times for each sample, and the number average of the calculated alkali-soluble polysaccharide content is taken as the average alkali-soluble polysaccharide content.

[0045] In one embodiment, the average content of acid-insoluble components in cellulose nanofibers is preferably 10% by mass or less, 5% by mass or less, or 3% by mass or less, based on 100% by mass of cellulose nanofibers, from the viewpoint of avoiding a decrease in the heat resistance of cellulose nanofibers and the resulting discoloration. The above content may be 0.1% by mass or more, 0.2% by mass or more, or 0.3% by mass or more, from the viewpoint of ease of manufacturing cellulose nanofibers.

[0046] The average acid-insoluble component content is determined using the Claesson method described in the non-patent literature (Wood Science Experiment Manual, edited by the Japan Wood Research Society, pp. 92-97, 2000). This method is understood in this industry as a method for measuring lignin content. After stirring the sample in sulfuric acid solution to dissolve cellulose and hemicellulose, etc., the sample is filtered through glass fiber filter paper, and the resulting residue contains the acid-insoluble components. The acid-insoluble component content is calculated from the weight of these acid-insoluble components. The acid-insoluble component content is measured three times for each sample, and the average of these measurements is taken as the average acid-insoluble component content.

[0047] [Chemical modification] Cellulose nanofibers may be chemically modified cellulose nanofibers (also called chemically modified cellulose nanofibers). Examples of chemically modified cellulose nanofibers include inorganic esters such as nitrate esters, sulfate esters, phosphate esters, silicate esters, and borate esters; organic esters such as acetylated and propionylated products; ethers such as methyl ethers, hydroxyethyl ethers, hydroxypropyl ethers, hydroxybutyl ethers, carboxymethyl ethers, and cyanoethyl ethers; and TEMPO oxides obtained by oxidizing the primary hydroxyl groups of cellulose. Chemically modified cellulose nanofibers may contain one or more types of modifying groups. In a preferred embodiment, the chemical modification is acylation using an esterifying agent, and particularly preferably acetylation. Preferred esterifying agents are acid halides, acid anhydrides, vinyl carboxylates, and carboxylic acids. Among these esterifying reagents, at least one selected from the group consisting of acetic anhydride, propionic anhydride, butyric anhydride, vinyl acetate, vinyl propionate, vinyl butyrate, and acetic acid, with acetic anhydride and vinyl acetate being particularly preferred from the viewpoint of reaction efficiency. The cellulose nanofibers may be chemically modified with a modifying agent, for example, at the stage of cellulose fiber raw material, during or after the defibration process, or they may be chemically modified during or after the preparation of the slurry as a dispersion, or during or after the drying process.

[0048] [Degree of acyl substitution (DS)] When cellulose nanofibers are chemically modified (e.g., by hydrophobication such as acylation), they tend to disperse well in rubber. On the other hand, when combined with a dispersant, for example, cellulose nanofibers can easily exhibit good dispersibility in rubber even if they are unsubstituted or have a low degree of substitution. When the cellulose nanofibers are esterified cellulose nanofibers, the degree of acyl substitution (DS) is preferably 0.1 or higher, or 0.2 or higher, or 0.25 or higher, or 0.3 or higher, or 0.5 or higher, in order to obtain esterified cellulose nanofibers with a high thermal decomposition onset temperature. Furthermore, since an unmodified cellulose skeleton remains in the esterified cellulose nanofibers, the degree of acyl substitution (DS) is preferably 2.0 or lower, or 1.8 or lower, or 1.5 or lower, or 1.2 or lower, or 1.0 or lower, or 0.8 or lower, or 0.7 or lower, or 0.6 or lower, or 0.5 or lower, in order to obtain esterified cellulose nanofibers that combine high tensile strength and dimensional stability derived from cellulose with a high thermal decomposition onset temperature derived from chemical modification.

[0049] The degree of acyl substitution (DS) of chemically modified cellulose nanofibers, when the modifying group is an acyl group, can be calculated from the reflected infrared absorption spectrum of esterified cellulose nanofibers based on the peak intensity ratio between the peak derived from the acyl group and the peak derived from the cellulose skeleton. The peak of the C=O absorption band based on the acyl group is at 1730 cm⁻¹. -1 The peak of the CO absorption band based on the cellulose backbone chain appears at 1030 cm⁻¹. -1 It appears there. The DS of esterified cellulose nanofibers is obtained by creating a correlation graph between the DS obtained from solid-state NMR measurements of esterified cellulose nanofibers (described later) and the modification rate (IR index 1030), which is defined as the ratio of the peak intensity of the absorption band of C=O based on the acyl group to the peak intensity of the absorption band of CO in the cellulose backbone chain, and a calibration curve calculated from the correlation graph. Degree of substitution DS = 4.13 × IR index (1030) This can be obtained by using [this method]. IR Index (1030) = H1730 / H1030 In the formula, H1730 and H1030 represent 1730 cm. -1 , 1030cm -1 This is the absorbance in the absorption band of the CO stretching vibration of the cellulose skeleton chain. However, each value is 1900 cm². -1 and 1500cm -1 The line connecting them is 800cm -1 and 1500cm -1 The line connecting these points is used as the baseline, and this value represents the absorbance when this baseline is set to 0.

[0050] The method for calculating the DS of esterified cellulose nanofibers using solid-state NMR is described below for freeze-dried esterified cellulose nanofibers. 13 The following formula can be used to determine the signal intensity (Inf) from a single carbon atom derived from the modifying group, based on the total area intensity (Inp) of the signals attributed to carbon atoms C1-C6 derived from the pyranose ring of cellulose, which appear in the range of 50 ppm to 110 ppm. DS = (Inf) × 6 / (Inp) For example, if the modifying group is an acetyl group, you can use the 23 ppm signal assigned to -CH3. Use 13 The conditions for 13C solid-state NMR measurement are as follows, for example: Equipment:Bruker Biospin Avance500WB Frequency: 125.77MHz Measurement method: DD / MAS method Waiting time: 75 seconds NMR sample tube: 4mmφ Total number of times: 640 (approximately 14 hours) MAS: 14,500Hz Chemical shift reference: Glycine (External reference: 176.03 ppm)

[0051] The thermal decomposition onset temperature of cellulose nanofibers (T D From the viewpoint of being able to exhibit the heat resistance and mechanical strength desired for automotive applications, etc., in one embodiment, the temperature is preferably 200°C or higher, or 210°C or higher, or 220°C or higher, or 230°C or higher, or 240°C or higher, or 250°C or higher, or 260°C or higher, or 270°C or higher, or 275°C or higher, or 280°C or higher, or 285°C or higher. A higher thermal decomposition onset temperature is preferable, but from the viewpoint of ease of manufacturing cellulose nanofibers, it may be, for example, 320°C or lower, or 310°C or lower, or 300°C or lower.

[0052] [Temperature at 1% weight loss (T 1% ), 250℃ weight loss rate (T 250℃ )] Temperature (T) when cellulose nanofibers lose 1 wt% of their weight. 1% In one embodiment, the temperature is preferably 230°C or higher, or 240°C or higher, or 250°C or higher, or 260°C or higher, or 270°C or higher, or 275°C or higher, or 280°C or higher, or 285°C or higher, or 290°C or higher, from the viewpoint of avoiding thermal degradation during melting and kneading and being able to exhibit mechanical strength. 1%Higher temperatures are preferable, but from the viewpoint of ease of manufacturing cellulose nanofibers, temperatures of, for example, 330°C or lower, 320°C or lower, or 310°C or lower may also be acceptable.

[0053] Weight loss rate of cellulose nanofibers at 250°C (T 250℃ From the viewpoint of avoiding thermal degradation during melting and kneading and being able to exhibit mechanical strength, in one embodiment, it is preferably 15% or less, or 12% or less, or 10% or less, or 8% or less, or 6% or less, or 5% or less, or 4% or less, or 3% or less. 250℃ While a lower concentration is preferable, from the viewpoint of ease of manufacturing cellulose nanofibers, it may be, for example, 0.1% or more, 0.5% or more, 0.7% or more, or 1.0% or more.

[0054] In this disclosure, T D This value is obtained from a graph in thermogravimetric (TG) analysis, where the horizontal axis is temperature and the vertical axis is weight retention percentage. Starting from the weight of cellulose nanofiber at 150°C (when moisture is almost completely removed) (weight loss 0 wt%), the temperature is further increased until the temperature at which a 1 wt% weight loss occurs (T 1% ) and temperature (T) when weight decreases by 2 wt% 2% Obtain a straight line passing through ( ). The temperature at the point where this line intersects with the horizontal line (baseline) passing through the starting point of the weight loss of 0 wt% is T. D This is how it is defined.

[0055] 1% weight loss temperature (T 1% ) is the above T D This is the temperature at which the weight decreases by 1% by weight, starting from the weight at 150°C, when the temperature is continuously increased using this method.

[0056] Weight loss rate of cellulose nanofibers at 250°C (T 250℃) is the weight loss rate when cellulose nanofibers are held at 250°C under a nitrogen flow for 2 hours in TG analysis. A porous sheet of cellulose nanofibers is heated from room temperature to 150°C at a rate of 10°C / min in a nitrogen flow of 100 ml / min, held at 150°C for 1 hour, then heated from 150°C to 250°C at a rate of 10°C / min, and held at 250°C for 2 hours. The weight W0 at the time of reaching 250°C is taken as the starting point, and the weight after being held at 250°C for 2 hours is taken as W1, which is calculated using the following formula. Weight change rate at 250℃ (%): (W1-W0) / W0×100

[0057] [Porous Sheet] Various physical properties of cellulose nanofibers (crystallinity, polymorphism, degree of polymerization, Mw, Mn, Mw / Mn, alkali-soluble content, average acid-insoluble content, T D , T 1% , T 250℃ Measurements of (etc.) can vary significantly depending on the form of the sample being measured. To ensure stable and reproducible measurements, a distortion-free porous sheet should be used as the measurement sample. The method for preparing the porous sheet is as follows.

[0058] First, a concentrated cake of cellulose nanofibers with a solid content of 10% by mass or more is added to tert-butanol, and then dispersed using a mixer or similar device until no aggregates remain. The concentration is adjusted to 0.5% by mass for every 0.5g of solid weight of cellulose nanofibers. 100g of the resulting tert-butanol dispersion is filtered on filter paper. Without removing the filtrate from the filter paper, it is sandwiched between two larger sheets of filter paper, and the edges of the larger sheets are pressed down with weights, and dried in a 150°C oven for 5 minutes. After that, the filter paper is peeled off to obtain a porous sheet with minimal distortion. The air permeability resistance R of this sheet is 10g / m² 2 Materials with a density of 100 sec / 100 ml or less are treated as porous sheets and used as measurement samples.

[0059] The air permeability resistance R was measured by measuring the basis weight W (g / m²) of a porous sheet sample that had been left standing for one day in an environment of 23°C and 50%RH. 2 After measuring the air permeability resistance (R) (sec / 100ml), the air permeability resistance is measured using a Wangyan-type air permeability resistance tester (for example, Asahi Seiko Co., Ltd., model EG01). At this time, 10 g / m³ is used according to the following formula. 2 Calculate the value per unit area. Weight: 10g / m 2 Air permeability resistance (sec / 100ml) = R / W × 10

[0060] [Specific surface area] The specific surface area of ​​the cellulose nanofiber is preferably 10 m², given that the highly refined cellulose nanofibers result in a good color tone for the resin composition and a good tack reduction effect on the styrene-based elastomer. 2 / g or more, or 15m 2 / g or more, or 20m 2 / g or more, or 30m 2 / g or more, or 40m 2 / g or more, or 50m 2 The amount is 200 m or more, and from the viewpoint of ease of production and handling of cellulose nanofibers, it is preferably 200 m 2 / g or less, or 170m 2 / g or less, or 160m 2 The specific surface area is less than or equal to / g. The specific surface area is determined using a specific surface area and pore distribution analyzer (e.g., Nova-4200e, manufactured by Quantachrome Instruments) by drying approximately 0.2g of the sample under vacuum at 120°C for 5 hours, and then measuring the amount of nitrogen gas adsorbed at the boiling point of liquid nitrogen at 5 points (multi-point method) within the range of relative vapor pressure (P / P0) of 0.05 to 0.2. The BET specific surface area (m²) is then calculated using the instrument's program. 2 It is measured by calculating ( / g).

[0061] Alternatively, the specific surface area of ​​the cellulose nanofiber is preferably 10 m², given that the transparency of the resin composition is good due to the highly refined cellulose nanofiber. 2 / g or more, or 15m 2 / g or more, or 20m2 / g or more, or 30m 2 / g or more, or 40m 2 / g or more, or 50m 2 The amount is 200 m or more, and from the viewpoint of ease of production and handling of cellulose nanofibers, it is preferably 200 m 2 / g or less, or 170m 2 / g or less, or 160m 2 The value is less than or equal to / g. The above range is particularly suitable in embodiments where a tack inhibitor containing cellulose nanofibers is used. Cellulose nanofibers with a relatively large specific surface area may be advantageous in terms of tack inhibitory effect. From this viewpoint, a preferred specific surface area is 10 m². 2 / g or more, or 20m 2 / g or more, or 30m 2 It is 1 / g or more.

[0062] Various physical properties of cellulose nanofibers contained in resin compositions, etc. (number average fiber length, number average fiber diameter, L / D ratio, degree of crystallinity, crystalline polymorphism, degree of polymerization, Mw, Mn, Mw / Mn, alkali-soluble content, average acid-insoluble content, T D , T 1% , T 250℃ (DS, specific surface area, etc.) are analyzed using the following method. The polymer components contained in the resin composition are dissolved in an organic or inorganic solvent capable of dissolving them, the cellulose nanofibers are separated, and after thorough washing with the solvent, the solvent is replaced with tert-butanol. Subsequently, the cellulose nanofiber tert-butanol slurry is analyzed using the same measurement method as described above, and various physical properties of the cellulose nanofibers in the resin composition are calculated.

[0063] When cellulose nanofibers are separated from a resin composition using THF, the weight increase rate of the cellulose nanofibers is preferably 190% or more, 250% or more, 300% or more, or 350% or more, from the viewpoint of interfacial strength between the resin and the cellulose nanofibers, and preferably 600% or less, 550% or less, or 500% or less, from the viewpoint of suppressing short fiber formation during kneading. The weight increase rate is a value measured by the method described in the [Examples] section of this disclosure.

[0064] In one embodiment, cellulose nanofibers may be provided in the form of a slurry containing a liquid medium, or in the form of a dry material such as particles, a film, or a bulk material. Examples of liquid mediums include water and / or organic solvents having a boiling point, and may contain one or more types of media. In the slurry form, the liquid medium content is 50% by mass or more, and in the dry material, the liquid medium content is less than 50% by mass. The liquid medium content is a value measured when heated at 180°C using an infrared heating type moisture meter (for example, A&D Corporation, product name "MX-50"). In embodiments using a tack inhibitor containing cellulose nanofibers, from the viewpoint of obtaining a better tack inhibitory effect, it is preferable that the cellulose nanofibers mixed with the styrene elastomer be in the form of a dry material.

[0065] The amount of cellulose nanofibers in 100% by mass of the resin composition is preferably 0.1% by mass or more, or 0.3% by mass or more, or 0.4% by mass or more, or 0.5% by mass or more, or 0.7% by mass or more, or 1.0% by mass or more, from the viewpoint of obtaining the advantages of cellulose nanofibers well, and preferably 20% by mass or less, or 15% by mass or less, or 10% by mass or less, from the viewpoint of the impact resistance of the resin composition. In embodiments using a tack inhibitor containing cellulose nanofibers, the amount of cellulose nanofibers that is particularly preferred from the viewpoint of exhibiting a good tack inhibitory effect is 0.5% by mass or more, or 0.7% by mass or more, or 1.0% by mass or more.

[0066] <Thermoplastic elastomer> In one embodiment, the thermoplastic elastomer includes a styrene-based elastomer, in another embodiment, an acid-modified styrene-based elastomer, in another embodiment, a styrene-based elastomer and an acid-modified styrene-based elastomer, and in another embodiment, a styrene-based elastomer and an acid-modified styrene-based elastomer. In this disclosure, in one embodiment, an elastomer is a substance (specifically, a natural or synthetic polymer) that is elastic at room temperature (23°C). In one embodiment, being elastic means that the storage modulus of elasticity measured by dynamic viscoelasticity measurement at 23°C and 10 Hz is between 1 MPa and 100 MPa. Examples of elastomers that the thermoplastic elastomer may include, in addition to styrene-based elastomers and acid-modified styrene-based elastomers, include one or more selected from natural rubber, conjugated diene compound polymers, aromatic compound-conjugated diene copolymers, hydrogenated aromatic compound-conjugated diene copolymers, polyolefins, polyester elastomers, polyurethane elastomers, polyamide elastomers, and elastomers having a core-shell structure. The amount of thermoplastic elastomer in 100% by mass of the resin composition is preferably 10% by mass or more, or 30% by mass or more, or 50% by mass or more, or 60% by mass or more, or 70% by mass or more, or 80% by mass or more, from the viewpoint of including other components in desired amounts, and preferably 99.5% by mass or less, or 99% by mass or less, or 98% by mass or less, or 95% by mass or less, or 90% by mass or less. The total ratio of styrene-based elastomer and acid-modified elastomer to 100% by mass of thermoplastic elastomer may, in one embodiment, be 1% by mass or more, 5% by mass or more, 10% by mass or more, 20% by mass or more, 50% by mass or more, or 70% by mass or more, and in one embodiment, it may be 100% by mass.

[0067] <Styrene-based elastomers and acid-modified styrene-based elastomers> A resin composition according to one embodiment includes a styrene elastomer. A resin composition according to one embodiment includes a styrene elastomer and an acid-modified styrene elastomer. In one embodiment, the styrene elastomer is a copolymer of a conjugated diene monomer and an aromatic vinyl monomer. Examples of conjugated diene monomers include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1,3-heptadiene, and 1,3-hexadiene, which may be used individually or in combination of two or more. The aromatic vinyl monomer is not particularly limited as long as it is a monomer copolymerizable with a conjugated diene monomer. Examples include styrene, m or p-methylstyrene, α-methylstyrene, ethylstyrene, p-tert-butylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, diphenylethylene, and divinylbenzene, which may be used individually or in combination of two or more. From the viewpoint of moldability of the resin composition and impact resistance of the molded article, styrene is preferred.

[0068] Examples of random copolymers include butadiene-styrene random copolymers, isoprene-styrene random copolymers, and butadiene-isoprene-styrene random copolymers. Regarding the compositional distribution of each monomer in the copolymer chain, examples include perfectly random copolymers with a composition close to statistically random, and tapered random copolymers with a gradient in the compositional distribution. The bonding mode of the conjugated diene polymer, i.e., the composition of 1,4-bonds, 1,2-bonds, etc., may be uniform or different between molecules.

[0069] A block copolymer may be a copolymer consisting of two or more blocks. For example, a block copolymer may have a structure such as AB, ABA, or ABAB, where block A is an aromatic vinyl monomer and block B is a block of conjugated diene monomer and / or a copolymer of aromatic vinyl monomer and conjugated diene monomer. The boundaries between each block do not necessarily need to be clearly distinguishable; for example, if block B is a copolymer of aromatic vinyl monomer and conjugated diene monomer, the aromatic vinyl monomer in block B may be distributed uniformly or tapered. Furthermore, block B may have multiple portions where the aromatic vinyl monomer is uniformly distributed and / or tapered. In addition, block B may have multiple segments with different aromatic vinyl monomer content. When multiple blocks A and block B exist in the copolymer, their molecular weights and compositions may be the same or different.

[0070] The styrene-based elastomer may be an aromatic vinyl compound-conjugated diene compound block copolymer or a hydrogenated version thereof. The block copolymer may be a mixture of two or more types in which one or more of the following are different: bond type, molecular weight, aromatic vinyl compound species, conjugated diene compound species, 1,2-vinyl content or the total amount of 1,2-vinyl content and 3,4-vinyl content, aromatic vinyl compound component content, hydrogenation rate, etc.

[0071] The styrene-based elastomer may be partially hydrogenated or fully hydrogenated. From the viewpoint of suppressing thermal degradation during processing, the hydrogenation rate of the hydrogenated material is preferably 50% or more, 80% or more, or 98% or more, and from the viewpoint of low-temperature toughness, it is preferably 50% or less, 20% or less, or 0% (i.e., unhydrogenated). Examples of hydrogenated conjugated diene polymers include the hydrogenated conjugated diene polymers exemplified above, and may be, for example, hydrogenated styrene-butadiene copolymers.

[0072] In one embodiment, the styrene elastomer is not acid-modified. In one embodiment, the styrene elastomer may be unmodified.

[0073] Acid-modified styrene elastomers may be acid-modified products of the styrene elastomers exemplified above. In this disclosure, an acid-modified styrene elastomer means that an acidic functional group is added to the molecular skeleton of a styrene elastomer via a chemical bond as an acid-modifying group. In this disclosure, an acidic functional group means a functional group that can react with basic functional groups, etc. Specific examples include hydroxyl groups, carboxyl groups, carboxylate groups, sulfo groups, acid anhydride groups, etc.

[0074] The acid modification rate, which is the mass ratio of acid-modified groups in 100% by mass of acid-modified styrene-based elastomer, is preferably 0.2% by mass or more, 0.3% by mass or more, 0.5% by mass or more, 1% by mass or more, or 1.5% by mass or more, based on 100% by mass of acid-modified styrene-based elastomer, from the viewpoint of void reduction effect due to good affinity with cellulose nanofibers, and preferably 2.5% by mass or less, 2.3% by mass or less, or 2% by mass or less, from the viewpoint of affinity with styrene-based elastomers. The acid modification rate is a value obtained by measuring a calibration curve created by measuring a calibration curve sample that has been pre-mixed with an acidic substance using an infrared absorption spectrum analyzer, and then measuring the sample based on the characteristic absorption band of the acid.

[0075] In one preferred embodiment, the acid-modified styrene elastomer is an acid-modified styrene elastomer that is an aromatic vinyl compound-conjugated diene compound copolymer (preferably an aromatic vinyl compound-conjugated diene compound block copolymer) or a hydrogenated thereof. Examples of such acid-modified styrene elastomers include elastomers that are modified products obtained by grafting an α,β-unsaturated dicarboxylic acid or its derivative onto an aromatic compound-conjugated diene copolymer (preferably a block copolymer) or its hydrogenated counterpart with or without a peroxide. Specific examples of α,β-unsaturated dicarboxylic acids and their derivatives include maleic acid, fumaric acid, maleic anhydride, and fumaric anhydride, with maleic anhydride being particularly preferred among these. In a preferred embodiment, the acid-modified styrene elastomer is an acid anhydride-modified styrene elastomer.

[0076] The styrene-based elastomer is preferably at least one selected from the group consisting of styrene-butadiene block copolymer, styrene-ethylene-butadiene block copolymer, styrene-ethylene-butylene block copolymer, styrene-butadiene-butylene block copolymer, styrene-isoprene block copolymer, styrene-ethylene-propylene block copolymer, styrene-isobutylene block copolymer, hydrogenated styrene-butadiene block copolymer, hydrogenated styrene-butadiene-butylene block copolymer, hydrogenated styrene-isoprene block copolymer, and styrene homopolymer (polystyrene), and more preferably one or more selected from the group consisting of styrene-butadiene block copolymer, hydrogenated styrene-butadiene block copolymer, and polystyrene, from the viewpoint of dispersibility of cellulose nanofibers or compatibility with acid-modified styrene-based elastomers. The acid-modified styrene-based elastomer is more preferably one or more acid-modified products of the above examples, from the viewpoint of compatibility with styrene-based elastomers.

[0077] The styrene unit ratio of the acid-modified styrene elastomer and the unit ratio of the styrene elastomer are preferably 10% by mass or more, 19% by mass or more, or 29% by mass or more, from the viewpoint of affinity between the acid-modified styrene elastomer and the styrene elastomer, and from the viewpoint of good expression of the advantageous properties inherent in the styrene elastomer, respectively. From the viewpoint of hardness, they are preferably 45% by mass or less, 40% by mass or less, or 35% by mass or less. The styrene unit ratio is a value that can be determined by the following method. Specifically, a predetermined amount of elastomer is dissolved in chloroform and measured using an ultraviolet spectrophotometer (e.g., Shimadzu Corporation, UV-2450), and the content of aromatic vinyl monomer units (styrene) is calculated using a calibration curve from the peak intensity of the absorption wavelength (262 nm) caused by the aromatic vinyl compound component (styrene).

[0078] The styrene unit ratio of the acid-modified styrene elastomer and the unit ratio of the styrene elastomer are preferably 10 mol% or more, 15 mol% or more, or 20 mol% or more, from the viewpoint of affinity between the acid-modified styrene elastomer and the styrene elastomer, and from the viewpoint of good expression of the advantageous properties inherent in the styrene elastomer, respectively. From the viewpoint of flexibility of the composition, they are preferably 40 mol% or less, 35 mol% or less, 30 mol% or less, or 25 mol% or less. These unit ratios are suitable in embodiments where a tack inhibitor containing cellulose nanofibers is used. The styrene unit ratio is a value determined by NMR spectroscopy.

[0079] The ratio of the styrene unit ratio of the styrene-based elastomer to the styrene unit ratio of the acid-modified styrene-based elastomer (styrene ratio of styrene-based elastomer / styrene ratio of acid-modified styrene-based elastomer) is preferably 0.3 or higher, or 0.6 or higher, or 0.9 or higher, from the viewpoint of affinity between the acid-modified styrene-based elastomer and the styrene-based elastomer, and similarly, preferably 2.5 or lower, or 2 or lower, or 1.5 or lower.

[0080] In acid-modified styrene elastomers, the ratio of styrene units to the acid modification rate (styrene unit ratio / acid modification rate) is preferably 5 or more, 10 or more, or 20 or more from the viewpoint of affinity with styrene elastomers, and preferably 90 or less, 85 or less, or 80 or less from the viewpoint of affinity with cellulose nanofibers.

[0081] With respect to styrene-based elastomers and acid-modified styrene-based elastomers, the amount of vinyl bonds in the conjugated diene bond units in the conjugated diene polymer (e.g., 1,2- or 3,4- bonds of butadiene) is preferably 5 mol% or more, or 10 mol% or more, or 13 mol% or more, or 15 mol% or more, and preferably 80 mol% or less, or 75 mol% or less, or 65 mol% or less, or 50 mol% or less, or 40 mol% or less. The amount of vinyl bonds in a conjugated diene bond unit (e.g., the amount of 1,2-bonds in butadiene) is, 13 This can be determined by 13C-NMR (quantitative mode). That is, 13 In 1C-NMR, integrating the peak areas shown below yields a value proportional to the carbon content of each structural unit, which can then be converted to the mass percentage of each structural unit. Styrene 145-147 ppm Vinyl 110-116 ppm Diene (cis) 24-28 ppm Diene (trans) 29-33 ppm

[0082] In a copolymer of a conjugated diene monomer and an aromatic vinyl monomer, the amount of aromatic vinyl monomer bonded to the conjugated diene monomer (hereinafter also referred to as the aromatic vinyl bond amount) may be preferably 5.0% by mass or more and 70% by mass or 10% by mass or more and 50% by mass or less, based on the total mass of the styrene-based elastomer. The aromatic vinyl bond amount can be determined by the ultraviolet absorbance of the phenyl group, and the conjugated diene bond amount can also be determined based on this.

[0083] The number-average molecular weight (Mn) of the acid-modified styrene elastomer is preferably 10,000 or more, or 30,000 or more, or 50,000 or more, from the viewpoint of affinity with styrene elastomers, and preferably 500,000 or less, or 250,000 or less, or 200,000 or less, from the viewpoint of affinity with cellulose nanofibers.

[0084] The number-average molecular weight (Mn) of the styrene-based elastomer is preferably 10,000 to 500,000, or 40,000 to 250,000, from the viewpoint of achieving both impact strength and fluidity.

[0085] In one embodiment, the total amount of acid-modified styrene elastomer and styrene elastomer in 100% by mass of the resin composition is 60% by mass or more, or 65% by mass or more, or 70% by mass or more, or 75% by mass or more. Such a resin composition can exhibit good rubber elasticity, weather resistance, chemical resistance, etc. From the viewpoint of including a desired amount of other components, particularly cellulose nanofibers, the above total amount is 90% by mass or less, or 85% by mass or less, or 80% by mass or less, in one embodiment.

[0086] The amount of acid-modified styrene elastomer per 100 parts by mass of styrene elastomer is preferably 0.5 parts by mass or more, or 1 part by mass or more, or 5 parts by mass or more, from the viewpoint of improving the surface smoothness of the molded article and the resistance to whitening during tension of the molded article (suppression of void formation), and preferably 50 parts by mass or less, or 40 parts by mass or less, or 30 parts by mass or less, from the viewpoint of suppressing discoloration, shrinkage during molding, and / or decrease in hardness caused by a large amount of acid-modified styrene elastomer.

[0087] The amount of acid-modified styrene elastomer per 1 part by mass of cellulose nanofiber is preferably 0.5 parts by mass or more, or 1 part by mass or more, or 5 parts by mass or more, from the viewpoint of improving the surface smoothness of the molded article and the resistance to whitening during tension of the molded article (suppression of void generation), and preferably 45 parts by mass or less, or 40 parts by mass or less, or 35 parts by mass or less, or 30 parts by mass or less, from the viewpoint of suppressing discoloration, shrinkage during molding, and / or decrease in hardness caused by a large amount of acid-modified styrene elastomer. In the resin composition according to one embodiment, the number of acid-modified groups of the acid-modified styrene elastomer can not be excessive compared to the number of hydroxyl groups on the surface portion of the cellulose nanofiber (specifically, the portion that gives surface area in the specific surface area measurement of cellulose nanofiber). The number of hydroxyl groups on the surface portion of the cellulose nanofiber in the resin composition can be calculated from the amount of cellulose nanofiber in the resin composition, the fiber diameter, and the specific surface area. For example, when using an acid-modified substance for the purpose of chemically modifying cellulose nanofibers, an excess amount of the acid-modified substance may be added to the cellulose nanofibers. However, in this embodiment, it may be advantageous to keep the amount of acid-modified styrene elastomer present in the resin composition to the minimum necessary while maintaining the desired affinity with the cellulose nanofibers. From this viewpoint, it is preferable that the amount of acid-modified styrene elastomer be adjusted so as not to be excessive relative to the number of hydroxyl groups in the cellulose nanofibers, and the upper limit amount exemplified above is suitable from this viewpoint.

[0088] The amount of acid-modified groups in the acid-modified styrene elastomer relative to 100% by mass of cellulose nanofibers is preferably 0.2% by mass or more, or 0.5% by mass or more, or 0.8% by mass or more, or 1.0% by mass or more, or 1.2% by mass or more, or 1.5% by mass or more, based on 100% by mass of the acid-modified styrene elastomer, from the viewpoint of affinity with cellulose nanofibers, and preferably 5.0% by mass or less, or 3.0% by mass or less, or 2.5% by mass or less, or 2.0% by mass or less, from the viewpoint of suppressing discoloration, shrinkage during molding, and / or hardness reduction caused by the acid-modified styrene elastomer.

[0089] The amount of acid-modified styrene elastomer in 100% by mass of the resin composition is preferably 0.5% by mass or more, or 1% by mass or more, or 5% by mass or more, from the viewpoint of improving the surface smoothness of the molded article and the resistance to whitening during tensile stress (suppression of void formation) of the molded article. From the viewpoint of suppressing discoloration, shrinkage during molding, and / or reduction in hardness caused by a large amount of acid-modified styrene elastomer, it is preferably 50% by mass or less, or 40% by mass or less, or 30% by mass or less. Note that acid-modified styrene elastomer is generally relatively expensive, so reducing the amount used is advantageous from a cost perspective.

[0090] In one embodiment, the behavior of the stress-strain curve (e.g., yield behavior) in a tensile test of the resin composition may be controlled according to the desired application of the resin composition by selecting the type and / or amount of acid-modified styrene elastomer.

[0091] The amount of styrene-based elastomer per 1 part by mass of cellulose nanofiber is preferably 0.5 parts by mass or more, or 1 part by mass or more, or 5 parts by mass or more, from the viewpoint of obtaining the good rubber elasticity, weather resistance and chemical resistance inherent in styrene-based elastomer, and preferably 250 parts by mass or less, or 200 parts by mass or less, or 150 parts by mass or less, from the viewpoint of improving the surface smoothness and hardness of the molded article.

[0092] The amount of styrene-based elastomer in 100% by mass of the resin composition is preferably 10% by mass or more, 20% by mass or more, or 30% by mass or more, from the viewpoint of allowing the advantageous properties inherent in the styrene-based elastomer to be fully exhibited, and preferably 98.8% by mass or less, 90% by mass or less, or 80% by mass or less, from the viewpoint of including other components in desired amounts.

[0093] The melt mass flow rate (MFR) of the styrene-based elastomer at 230°C and 2.16 kg is preferably 20 g / 10 min or less, or 15 g / 10 min or less, or 10 g / 10 min or less, or 8 g / 10 min or less, or 5 g / 10 min or less, from the viewpoint of obtaining good mechanical properties of the resin composition, and preferably 0.1 g / 10 min or more, or 0.5 g / 10 min or more, or 1.0 g / 10 min or more, from the viewpoint of facilitating melt processing.

[0094] <Styrene-based elastomers and acid-modified styrene-based elastomers in embodiments using a tack inhibitor containing cellulose nanofibers> The following describes examples of styrene-based elastomers and acid-modified styrene-based elastomers that are particularly suitable in embodiments using a tack inhibitor containing cellulose nanofibers. In one embodiment, the resin composition contains an acid-modified styrene-based elastomer. It has been found that the presence of an acid-modified styrene-based elastomer in addition to cellulose nanofibers can further improve the tensile strength, tensile modulus, tensile elongation at break, and / or hardness of the molded article, while also reducing undesirable conditions such as whitening and discoloration of the molded article. Although not bound by theory, it is thought that the reaction between the hydroxyl groups of cellulose nanofibers and the acid-modified groups of the acid-modified styrene-based elastomer strengthens their interface, making it less likely for delamination to occur between the styrene-based elastomer, cellulose nanofibers, and acid-modified styrene-based elastomer when an external force is applied to the molded article, and also making it less likely for discoloration to occur due to thermal degradation of the cellulose nanofibers. As a result, the property-improving effect of cellulose nanofibers is well exhibited, void generation in the molded article due to delamination is suppressed, whitening is reduced, and discoloration of the cellulose nanofibers is also suppressed. The presence of an acid-modified styrene elastomer in the resin composition is also advantageous in that it further reduces the tackiness caused by the styrene elastomer.

[0095] In one embodiment of the resin composition, the acid-modified styrene elastomer and the styrene elastomer are miscible without phase separation and form a continuous phase. In one embodiment of the resin composition, the acid-modified styrene elastomer forms a first phase, and the styrene elastomer forms a second phase separated from the first phase. In one embodiment, the total amount of the acid-modified styrene elastomer and the styrene elastomer is 60% by mass or more of 100% by mass of the resin composition. In one embodiment, the second phase is a continuous phase. In one embodiment, the first phase is a dispersed phase and the second phase is a continuous phase. The dispersed phase may have, for example, domain sizes of 20 nm to 10 μm. The domain size can be determined from scanning electron microscope (SEM) images. Alternatively, in one embodiment, the first phase and the second phase may each be a continuous phase. Due to the phase separation between the acid-modified styrene elastomer and the styrene elastomer, the styrene elastomer portion in the resin composition contributes to the expression of the inherently good properties of the styrene elastomer, while the acid-modified styrene elastomer portion interposes between the styrene elastomer and cellulose nanofibers due to its good affinity with both, contributing to a further improvement in the property-improving effect of the cellulose nanofibers.

[0096] The acid-modified styrene elastomer may be an acid-modified product of the styrene elastomer exemplified above. Preferred examples of acid-modified styrene elastomers are as exemplified above in this disclosure.

[0097] The amount of styrene-based elastomer per 1 part by mass of cellulose nanofiber is preferably 0.5 parts by mass or more, or 1 part by mass or more, or 3 parts by mass or more, or 5 parts by mass or more, or 7 parts by mass or more, or 10 parts by mass or more, or 15 parts by mass or more, from the viewpoint of obtaining the good rubber elasticity, weather resistance and chemical resistance inherent in styrene-based elastomer, and preferably 250 parts by mass or less, or 150 parts by mass or less, or 100 parts by mass or less, from the viewpoint of reducing tackiness and improving hardness of the molded article.

[0098] The amount of styrene-based elastomer in 100% by mass of the resin composition is preferably 10% by mass or more, or 20% by mass or more, or 40% by mass or more, or 50% by mass or more, or 60% by mass or more, or 70% by mass or more, or 80% by mass or more, from the viewpoint of obtaining the advantages inherent in styrene-based elastomer, and preferably 99.5% by mass or less, or 99% by mass or less, or 98% by mass or less, or 95% by mass or less, or 90% by mass or less, from the viewpoint of including other components in desired amounts.

[0099] The melt mass flow rate (MFR) of the styrene-based elastomer at 230°C and 2.16 kg is preferably 20 g / 10 min or less, or 15 g / 10 min or less, or 10 g / 10 min or less, or 8 g / 10 min or less, or 5 g / 10 min or less, from the viewpoint of obtaining good mechanical properties of the resin composition, and preferably 0.1 g / 10 min or more, or 0.5 g / 10 min or more, or 1.0 g / 10 min or more, from the viewpoint of facilitating melt processing.

[0100] The acid modification rate, which is the mass ratio of acid-modified groups in 100% by mass of the acid-modified styrene-based elastomer, is preferably 0.2% by mass or more, or 0.5% by mass or more, or 0.8% by mass or more, or 1.0% by mass or more, or 1.2% by mass or more, or 1.5% by mass or more, based on 100% by mass of the acid-modified styrene-based elastomer, from the viewpoint of affinity with cellulose nanofibers, and preferably 5.0% by mass or less, or 3.0% by mass or less, or 2.5% by mass or less, or 2.0% by mass or less, from the viewpoint of affinity with styrene-based elastomers.

[0101] The ratio of the styrene unit ratio of the styrene-based elastomer to the styrene unit ratio of the acid-modified styrene-based elastomer (styrene ratio of styrene-based elastomer / styrene ratio of acid-modified styrene-based elastomer) is preferably 0.3 or higher, or 0.35 or higher, or 0.4 or higher, from the viewpoint of affinity between the acid-modified styrene-based elastomer and the styrene-based elastomer, and similarly, preferably 4 or lower, or 3 or lower, or 2 or lower.

[0102] In acid-modified styrene elastomers, the ratio of styrene units to the acid modification rate (styrene unit ratio / acid modification rate) is preferably 5 or more, or 8 or more, or 12 or more, from the viewpoint of affinity with styrene elastomers, and preferably 90 or less, or 50 or less, or 30 or less, from the viewpoint of affinity with cellulose nanofibers.

[0103] The melt mass flow rate (MFR) of the acid-modified styrene elastomer at 230°C and 2.16 kg is preferably 0.1 g / 10 min or more, or 0.5 g / 10 min or more, or 1.0 g / 10 min, from the viewpoint of affinity with the styrene elastomer, and preferably 20 g / 10 min or less, or 15 g / 10 min or less, or 10 g / 10 min or less, or 8 g / 10 min or less, or 5 g / 10 min or less, from the viewpoint of affinity with cellulose nanofibers.

[0104] In one embodiment, the total amount of acid-modified styrene elastomer and styrene elastomer in 100% by mass of the resin composition is 50% by mass or more, or 60% by mass or more, or 70% by mass or more, or 80% by mass or more. Such a resin composition can exhibit good rubber elasticity, weather resistance, chemical resistance, etc. From the viewpoint of including a desired amount of other components, particularly cellulose nanofibers, the above total amount is 99.5% by mass or less, or 99% by mass or less, or 98% by mass or less, or 95% by mass or less, or 90% by mass or less, in one embodiment.

[0105] The amount of acid-modified styrene elastomer per 100 parts by mass of styrene elastomer is preferably 0.5 parts by mass or more, or 1 part by mass or more, or 5 parts by mass or more, from the viewpoint of obtaining the advantages of the acid-modified styrene elastomer well, and preferably 100 parts by mass or less, or 50 parts by mass or less, or 20 parts by mass or less, or 10 parts by mass or less, from the viewpoint of suppressing discoloration, shrinkage during molding, and / or decrease in hardness caused by a large amount of acid-modified styrene elastomer.

[0106] The amount of acid-modified styrene elastomer per 1 part by mass of cellulose nanofiber is preferably 0.1 parts by mass or more, or 0.3 parts by mass or more, or 0.5 parts by mass or more, or 0.8 parts by mass or more, from the viewpoint of obtaining the advantages of the acid-modified styrene elastomer well, and preferably 45 parts by mass or less, or 30% by mass or less, or 20 parts by mass or less, or 10 parts by mass or less, or 5 parts by mass or less, or 3 parts by mass or less, or 2 parts by mass or less, from the viewpoint of suppressing discoloration, shrinkage during molding, and / or decrease in hardness caused by a large amount of acid-modified styrene elastomer.

[0107] The amount of acid-modified styrene elastomer in 100% by mass of the resin composition is preferably 0.5% by mass or more, or 1% by mass or more, or 2% by mass or more, or 3% by mass or more, or 4% by mass or more, from the viewpoint of obtaining the advantages of acid-modified styrene elastomer well, and preferably 50% by mass or less, or 30% by mass or less, or 20% by mass or less, or 10% by mass or less, from the viewpoint of suppressing discoloration, shrinkage during molding, and / or decrease in hardness caused by a large amount of acid-modified styrene elastomer. Note that acid-modified styrene elastomer is generally relatively expensive, so reducing the amount used is also advantageous from a cost perspective.

[0108] The content of styrene-based elastomer in the resin composition components is preferably 10% by mass or more, or 20% by mass or more, and preferably 90% by mass or less, or 85% by mass or less, or 80% by mass or less.

[0109] The total content of styrene-based elastomer and acid-modified styrene-based elastomer in the resin composition components is preferably 40% by mass or more, or 45% by mass or more, or 50% by mass or more, and preferably 99% by mass or less, or 95% by mass or less, or 90% by mass or less.

[0110] In the resin composition components, the content of acid-modified styrene elastomer relative to 100 parts by mass of the total of styrene elastomer and acid-modified styrene elastomer is preferably 5 parts by mass or more, or 10 parts by mass or more, or 15 parts by mass or more, and preferably 70 parts by mass or less, or 65 parts by mass or less, or 60 parts by mass or less.

[0111] The amount of cellulose nanofibers in the resin composition is preferably 1 part by mass or more, or 2 parts by mass or more, or 3 parts by mass or more, and preferably 70 parts by mass or less, or 65 parts by mass or less, or 60 parts by mass or less, based on 100 parts by mass of the total of the styrene-based elastomer and the acid-modified styrene-based elastomer.

[0112] The mass ratio of [cellulose nanofiber] / [total of styrene-based elastomer and acid-modified styrene-based elastomer] in the resin composition components is preferably 1 / 99 to 60 / 40, or 2 / 98 to 50 / 50, or 3 / 97 to 40 / 60.

[0113] <Liquid polymer> In one embodiment, the resin composition may contain a liquid polymer. A liquid polymer means a polymer that is fluid at 23°C. In one embodiment, the liquid polymer has a glass transition temperature (Tg). In one embodiment, the liquid polymer may be a conjugated diene polymer or a non-conjugated diene polymer. In one embodiment, the liquid polymer is liquid rubber. In this disclosure, liquid rubber means a substance that is fluid at 23°C and forms a rubber elastic body by crosslinking (more specifically vulcanization) and / or chain extension. That is, in one embodiment, the liquid rubber is an uncured product.

[0114] Furthermore, having fluidity means, in one embodiment, that a liquid polymer dissolved in cyclohexane is placed in a vial measuring 21 mm in diameter and 50 mm in length at 23°C and then dried. When the vial is filled to a height of 1 mm with the liquid polymer and sealed, and the vial is left upside down for 24 hours, a movement of 0.1 mm or more of the substance in the vertical direction can be observed.

[0115] The liquid polymer may have the monomer composition of a general polymer, and is preferably relatively low in molecular weight from the viewpoint of ease of handling and good dispersibility of cellulose nanofibers. In one embodiment, the liquid polymer exhibits liquid form by having a number-average molecular weight (Mn) of 80,000 or less. Unless otherwise specified, the number-average molecular weight and weight-average molecular weight of the various polymers in this disclosure are values ​​obtained in terms of standard polystyrene using gel permeation chromatography with chloroform as the solvent and a measurement temperature of 40°C.

[0116] In one embodiment, the liquid polymer may be combined with cellulose nanofibers to form a masterbatch, and such a masterbatch may be combined with a resin to form the resin composition of the present disclosure.

[0117] The number-average molecular weight (Mn) of the liquid polymer is preferably 1,000 or more, or 1,500 or more, or 2,000 or more, from the viewpoint of thermal stability and the effect of improving the dispersibility of cellulose nanofibers in the resin. It is preferably 80,000 or less, or 50,000 or less, or 40,000 or less, or 30,000 or less, or 10,000 or less, in terms of having high fluidity suitable for good dispersion when dispersing cellulose nanofibers in the liquid polymer.

[0118] The weight-average molecular weight (Mw) of the liquid polymer is preferably 1,000 or more, 2,000 or more, or 4,000 or more, from the viewpoint of thermal stability and the effect of improving the dispersibility of cellulose nanofibers in the resin. It is preferably 240,000 or less, 150,000 or less, or 30,000 or less, in terms of having high fluidity suitable for good dispersion when dispersing cellulose nanofibers in the liquid polymer.

[0119] The ratio (Mw / Mn) of the number-average molecular weight (Mn) to the weight-average molecular weight (Mw) of the liquid polymer is preferably 1.5 or higher, or 1.8 or higher, or 2 or higher, in that the degree of variation in molecular weight allows for a high degree of compatibility of multiple properties (in one embodiment, a high degree of compatibility between good dispersion of cellulose nanofibers in the resin and a good flexural modulus of the resin composition). In that the variation in molecular weight is not excessively large and the desired physical properties of the resin composition can be obtained stably, for example, in terms of compatibility between fluidity and impact resistance, it is preferably 10 or lower, or 8 or lower, or 5 or lower, or 3 or lower, or 2.7 or lower.

[0120] Liquid polymers can have good thermal stability. The thermal decomposition onset temperature of liquid polymers (T D In terms of good thermal stability, the temperature is, in one embodiment, above 200°C, or 210°C or above, or 230°C or above, or 250°C or above, or 300°C or above. A higher thermal decomposition onset temperature is preferable, but from the viewpoint of the availability of the liquid polymer, in one embodiment it may be 500°C or below, or 450°C or below, or 400°C or below.

[0121] The glass transition temperature of the liquid polymer is preferably -150°C or higher, or -120°C or higher, or -100°C or higher, in terms of good thermal stability, and preferably 25°C or lower, or 10°C or lower, or 0°C or lower, in terms of good fluidity.

[0122] In one embodiment, the liquid polymer comprises a diene polymer, and in another embodiment, a conjugated diene polymer or a non-conjugated diene polymer or hydrogenated thereof. The above polymer or its hydrogenated counterpart may be an oligomer. The monomers constituting the liquid polymer may be unmodified or modified (e.g., acid-modified, hydroxyl-modified, etc.). In one embodiment, the liquid polymer may have reactive groups at both ends (e.g., one or more selected from the group consisting of hydroxyl groups, carboxyl groups, isocyanate groups, thio groups, amino groups, and halo groups), and therefore may be bifunctional. These reactive groups contribute to crosslinking and / or chain extension of the liquid polymer.

[0123] [Conjugated diene polymers] The conjugated diene polymer may be a homopolymer, or a copolymer of two or more conjugated diene monomers, or a copolymer of a conjugated diene monomer and another monomer. The copolymer may be random or block-shaped.

[0124] Examples of conjugated diene monomers include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1,3-heptadiene, and 1,3-hexadiene, which may be used individually or in combination of two or more.

[0125] In one embodiment, the conjugated diene polymer is a copolymer of the above-mentioned conjugated diene monomer and an aromatic vinyl monomer. The aromatic vinyl monomer is not particularly limited as long as it is a monomer copolymerizable with a conjugated diene monomer. Examples include styrene, m or p-methylstyrene, α-methylstyrene, ethylstyrene, p-tert-butylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, diphenylethylene, and divinylbenzene, which may be used individually or in combination of two or more. From the viewpoint of moldability of the resin composition and impact resistance of the molded article, styrene is preferred.

[0126] Examples of random copolymers include butadiene-isoprene random copolymers, butadiene-styrene random copolymers, isoprene-styrene random copolymers, and butadiene-isoprene-styrene random copolymers. Regarding the compositional distribution of each monomer in the copolymer chain, examples include perfectly random copolymers with a composition close to statistically random, and tapered random copolymers with a gradient in the compositional distribution. The bonding mode of the conjugated diene polymer, i.e., the composition of 1,4-bonds, 1,2-bonds, etc., may be uniform or different between molecules.

[0127] A block copolymer may be a copolymer consisting of two or more blocks. For example, a block copolymer may have a structure such as AB, ABA, or ABAB, where block A is an aromatic vinyl monomer and block B is a block of conjugated diene monomer and / or a copolymer of aromatic vinyl monomer and conjugated diene monomer. The boundaries between each block do not necessarily need to be clearly distinguishable; for example, if block B is a copolymer of aromatic vinyl monomer and conjugated diene monomer, the aromatic vinyl monomer in block B may be distributed uniformly or tapered. Furthermore, block B may have multiple portions where the aromatic vinyl monomer is uniformly distributed and / or tapered. In addition, block B may have multiple segments with different aromatic vinyl monomer content. When multiple blocks A and block B exist in the copolymer, their molecular weights and compositions may be the same or different.

[0128] The block copolymer may be a mixture of two or more types in which one or more of the following are different: bond type, molecular weight, aromatic vinyl compound species, conjugated diene compound species, 1,2-vinyl content or the total amount of 1,2-vinyl content and 3,4-vinyl content, aromatic vinyl compound component content, hydrogenation rate, etc.

[0129] In conjugated diene polymers, the amount of vinyl bonds in the conjugated diene bond units (e.g., 1,2- or 3,4- bonds of butadiene) is preferably 10 mol% or more and 75 mol% or less, or 13 mol% or more and 65 mol% or less. The amount of vinyl bonds in a conjugated diene bond unit (e.g., the amount of 1,2-bonds in butadiene) is, 13 This can be determined by 13C-NMR (quantitative mode). That is, 13 In 1C-NMR, integrating the peak areas shown below yields a value proportional to the carbon content of each structural unit, which can then be converted to the mass percentage of each structural unit. Styrene 145-147 ppm Vinyl 110-116 ppm Diene (cis) 24-28 ppm Diene (trans) 29-33 ppm

[0130] In a copolymer of a conjugated diene monomer and an aromatic vinyl monomer, the amount of aromatic vinyl monomer bonded to the conjugated diene monomer (hereinafter also referred to as the amount of aromatic vinyl bonded) may be preferably 5 mol% to 70 mol%, or 10 mol% to 50 mol%, based on 100% of the total moles of the conjugated diene polymer.

[0131] Examples of hydrogenated conjugated diene polymers include those exemplified above, such as hydrogenated butadiene homopolymers, isoprene homopolymers, styrene-butadiene copolymers, and acrylonitrile-butadiene copolymers.

[0132] In a preferred embodiment, the liquid polymer is one or more selected from the group consisting of polybutadiene, butadiene-styrene copolymer, polyisoprene, and polychloroprene. These may be derivatives (e.g., maleic anhydride modified, methacrylic acid modified, terminal hydroxyl group modified, hydrogenated, and combinations thereof).

[0133] [Non-conjugated diene polymers] The non-conjugated diene polymer may be a homopolymer, or a copolymer of two or more non-conjugated diene monomers, or a copolymer of a non-conjugated diene monomer and another monomer. The copolymer may be random or block. Examples of non-conjugated diene polymers include olefin polymers (e.g., liquid paraffin), silicone polymers, and acrylic polymers. For example, when the liquid polymer is liquid rubber, the non-conjugated diene polymer may be: Olefin polymers such as ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-butene-diene rubber, and ethylene-α-olefin copolymers. Examples include butyl rubber, brominated butyl rubber, acrylic rubber, fluororubber, silicone rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, α,β-unsaturated nitrile-acrylic acid ester-conjugated diene copolymer rubber, urethane rubber, and polysulfide rubber.

[0134] In ethylene-α-olefin copolymers, monomers that can copolymerize with ethylene units include propylene, butene-1, pentene-1, 4-methylpentene-1, hexene-1, heptene-1, octene-1, nonene-1, decene-1, undecene-1, dodecene-1, tridecene-1, tetradecene-1, pentadecene-1, hexadecene-1, heptadecene-1, octadecene-1, nonadecene-1, or eicosene-1, aliphatic substituted vinyl monomers such as isobutylene, and styrene. Examples include aromatic vinyl monomers such as substituted styrene, vinyl acetate, acrylic acid esters, methacrylic acid esters, glycidyl acrylic acid esters, glycidyl methacrylic acid esters, hydroxyethyl methacrylic acid esters, nitrogen-containing vinyl monomers such as acrylamide, allylamine, vinyl-p-aminobenzene, and acrylonitrile, and dienes such as butadiene, cyclopentadiene, 1,4-hexadiene, and isoprene.

[0135] The ethylene-α-olefin copolymer is preferably a copolymer of ethylene and one or more α-olefins having 3 to 20 carbon atoms, more preferably a copolymer of ethylene and one or more α-olefins having 3 to 16 carbon atoms, and most preferably a copolymer of ethylene and one or more α-olefins having 3 to 12 carbon atoms.

[0136] From the viewpoint of exhibiting impact resistance, the molecular weight of the ethylene-α-olefin copolymer is preferably 10,000 or more, more preferably 10,000 to 100,000, more preferably 10,000 to 80,000, and even more preferably 20,000 to 60,000, as measured by a gel permeation chromatography analyzer using 1,2,4-trichlorobenzene as a solvent at 140°C with a polystyrene standard.

[0137] Furthermore, from the viewpoint of ease of handling during processing, the ethylene unit content of the ethylene-α-olefin copolymer is preferably 30 to 95% by mass relative to the total amount of the ethylene-α-olefin copolymer.

[0138] Ethylene-α-olefin copolymers can be produced by conventionally known manufacturing methods, such as those described in Japanese Patent Publication No. 4-12283, Japanese Unexamined Patent Publication No. 60-35006, Japanese Unexamined Patent Publication No. 60-35007, Japanese Unexamined Patent Publication No. 60-35008, Japanese Unexamined Patent Publication No. 5-155930, Japanese Unexamined Patent Publication No. 3-163088, and U.S. Patent No. 5,272,236.

[0139] In one embodiment, the liquid polymer comprises one or more selected from the group consisting of diene rubber, silicone rubber, urethane rubber, and polysulfide rubber, and hydrogenated versions thereof, and preferably comprises diene rubber.

[0140] The viscosity of the liquid polymer at 25°C is preferably 1,000,000 mPa·s or less, or 500,000 mPa·s or less, or 200,000 mPa·s or less, from the viewpoint of good dispersion of cellulose nanofibers in the liquid polymer, and preferably 100 mPa·s or more, or 300 mPa·s or more, or 500 mPa·s or more, from the viewpoint of thermal stability, effect of improving the dispersibility of cellulose nanofibers in the resin, and mechanical properties of the resin composition.

[0141] The viscosity of the liquid polymer at 50°C is preferably 1,000,000 mPa·s or less, or 500,000 mPa·s or less, or 200,000 mPa·s or less, or 100,000 mPa·s or less, from the viewpoint of good dispersion of cellulose nanofibers in the liquid polymer and good dispersion of cellulose nanofibers in the resin by heating and kneading, and preferably 50 mPa·s or more, or 100 mPa·s or more, from the viewpoint of thermal stability, effect of improving the dispersibility of cellulose nanofibers in the resin, and mechanical properties of the resin composition.

[0142] The viscosity of the liquid polymer at 80°C is preferably 1,000,000 mPa·s or less, or 500,000 mPa·s or less, or 250,000 mPa·s or less, or 100,000 mPa·s or less, from the viewpoint of good dispersion of cellulose nanofibers in the liquid polymer and good dispersion of cellulose nanofibers in the resin by heating and kneading, and preferably 50 mPa·s or more, or 100 mPa·s or more, or 300 mPa·s or more, from the viewpoint of thermal stability, effect of improving the dispersibility of cellulose nanofibers in the resin, and mechanical properties of the resin composition.

[0143] The viscosity of the liquid polymer at 0°C is preferably 2,000,000 mPa·s or less, or 1,000,000 mPa·s or less, or 400,000 mPa·s or less, from the viewpoint of good dispersion of cellulose nanofibers in the liquid polymer, and preferably 200 mPa·s or more, or 600 mPa·s or more, or 1,000 mPa·s or more, from the viewpoint of thermal stability, effect of improving the dispersibility of cellulose nanofibers in the resin, and mechanical properties of the resin composition.

[0144] It is preferable that the viscosity of the liquid polymer at 80°C, 50°C, 25°C, and 0°C is all within the above range, as this allows for good dispersion of cellulose nanofibers in the liquid polymer over a wide mixing temperature range.

[0145] The viscosity of the liquid polymer is measured using a Type B viscometer at a rotation speed of 10 rpm.

[0146] In the resin composition, the amount of liquid polymer per 100 parts by mass of styrene-based elastomer is preferably 0.1 parts by mass or more, or 0.3 parts by mass or more, or 0.5 parts by mass or more, or 1.0 part by mass or more, from the viewpoint of obtaining the advantages of the liquid polymer well, and preferably 15 parts by mass or less, or 10 parts by mass or less, or 5 parts by mass or less, from the viewpoint of obtaining the advantages of acid-modified styrene-based elastomer well, or from the viewpoint of obtaining a resin composition that exhibits the inherent physical properties of styrene-based elastomer.

[0147] In the resin composition, the amount of liquid polymer per 100 parts by mass of cellulose nanofiber is preferably 5 parts by mass or more, or 10 parts by mass or more, or 20 parts by mass or more, or 30 parts by mass or more, or 40 parts by mass or more, from the viewpoint of obtaining good advantages of the liquid polymer, and preferably 400 parts by mass or less, or 200 parts by mass or less, or 100 parts by mass or less, from the viewpoint of obtaining good physical properties of the resin composition and the resin molded article.

[0148] From the viewpoint of obtaining the advantages of liquid polymers well, the content of liquid polymer in the resin composition is preferably 0.1% by mass or more, or 0.3% by mass or more, or 1.0% by mass or more, and from the viewpoint of obtaining good physical properties of the resin composition and resin molded article, it is preferably 20% by mass or less, or 10% by mass or less, or 7% by mass or less, or 5% by mass or less.

[0149] <Dispersant> In one embodiment, the resin composition includes a dispersant. In one embodiment, it is even more preferable, from the viewpoint of more uniformly dispersing cellulose nanofibers in the resin composition, that the dispersant has a hydrophilic segment and a hydrophobic segment within the same molecule (i.e., is an amphiphilic molecule). In a preferred embodiment, the resin composition includes a polyoxyethylene unit-containing polymer.

[0150] [Amphiphilic molecules] In amphiphilic molecules, the hydrophilic segment is the part that exhibits good affinity with cellulose nanofibers by containing a hydrophilic structure. Specifically, hydrophilic structures include hydroxyl groups, thiol groups, carboxyl groups, sulfonic acid groups, sulfate ester groups, phosphate groups, boronic acid groups, silanol groups, groups derived from sugars such as sorbitan and sucrose, groups derived from glycerin, groups represented by -OM, -COOM, -SO3M, -OSO3M, -HMPO4, and -M2PO4 (where M represents an alkali metal or alkaline earth metal), as well as primary to tertiary amines and quaternary ammonium salts. The counteranions of the above quaternary ammonium salts include one or more hydrophilic groups selected from the group consisting of halogen ions such as hydroxide ions, fluoride ions, chloride ions, bromide ions, and iodide ions, as well as nitrate ions, formate ions, acetate ions, trifluoroacetate ions, p-toluenesulfonate ions, hexafluorophosphate, and tetrafluoroborate.

[0151] Examples of hydrophilic segments include polyethylene glycol segments, segments containing repeating units with quaternary ammonium salt structures, polyvinyl alcohol segments, polyvinylpyrrolidone segments, polyacrylic acid segments, carboxyvinyl polymer segments, cationized guar gum segments, hydroxyethylcellulose segments, methylcellulose segments, carboxymethylcellulose segments, and polyurethane soft segments (specifically diol segments). Nonionic polyoxyethylene derivatives are particularly preferred, and the polyoxyethylene chain length of the polyoxyethylene derivative may be 3 or more, or 5 or more, or 10 or more, or 15 or more. While longer chain lengths increase affinity with cellulose nanofibers, the polyoxyethylene chain length may be 60 or less, or 50 or less, or 40 or less, or 30 or less, or 20 or less, from the viewpoint of balancing with the desired properties (e.g., mechanical properties) of the resin molded article.

[0152] Examples of hydrophobic segments include segments containing hydrocarbons, segments containing fluorinated carbon, segments containing alkylene oxide units with 3 or more carbon atoms (e.g., PPG blocks), and segments containing polymer structures. Preferred hydrocarbon segments include alkyl type, alkenyl type, alkyl ether type, alkenyl ether type, alkylphenyl ether type, alkenylphenyl ether type, rosin ester type, bisphenol A type, β-naphthyl type, styrene-phenyl type, and hydrogenated castor oil type. The number of carbon atoms in the alkyl chain or alkenyl chain of the hydrophobic group (in the case of alkylphenyl or alkenylphenyl, the number of carbon atoms excluding the phenyl group) is preferably 2 or more, or 5 or more, or 10 or more, or 12 or more, or 16 or more. As for the segment having fluorinated carbon, linear or branched alkyl types with 1 to 20 carbon atoms are preferred. Preferred polymer structures include acrylic polymers, styrene resins, vinyl chloride resins, vinylidene chloride resins, polyolefin resins, amino acid lactams including ring-opening polymers of lactams, polymers composed of diamines and dicarboxylic acids, polyacetal resins, polycarbonate resins, polyester resins, polyphenylene sulfide resins, polysulfone resins, polyetherketone resins, polyimide resins, fluorine resins, hydrophobic silicone resins, melamine resins, epoxy resins, phenolic resins, and the like. These hydrophobic segments may have either a linear or branched structure. Furthermore, the hydrophobic segments may have a single-chain structure or a structure of two or more chains, and if they have a structure of two or more chains, they may have multiple types of hydrophobic groups.

[0153] The structure of amphiphilic molecules is not particularly limited, but when the hydrophilic segment is A and the hydrophobic segment is B, examples include linear copolymers such as AB-type block copolymers, ABA-type block copolymers, and BAB-type block copolymers; tribranched copolymers containing A and B; tetrabranched copolymers containing A and B; star-shaped copolymers containing A and B; monocyclic copolymers containing A and B; polycyclic copolymers containing A and B; cage copolymers containing A and B; and graft copolymers containing A and B. When multiple hydrophilic segments are present in a molecule, their molecular structure may be a single type or a combination of two or more types. Similarly, when multiple hydrophobic segments are present in a molecule, their molecular structure may be a single type or a combination of two or more types.

[0154] (Surfactants) Any of the following can be used as the amphiphilic molecule: anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants. The dispersant may be a polymeric surfactant, a reactive surfactant, or the like.

[0155] Examples of nonionic surfactants include fatty acid dialkanolamides (e.g., lauric acid diethanolamide), polyoxyalkylene fatty acid amides (e.g., polyoxyethylene stearic acid amide), polyoxyalkylene aryl ethers (e.g., polyoxyethylene phenyl ether), polyoxyalkylene alkylaryl ethers (e.g., polyoxyethylene octylphenyl ether), polyoxyalkylene alkyl or alkenyl ethers (e.g., polyoxyethylene lauryl ether, polyoxyethylene stearyl ether), fatty acid esters of polyhydric alcohols (e.g., polyethylene glycol mono or distearate ester, polyethylene glycol mono or dilaurate ester, polyoxyethylene hydrogenated castor oil), glycerin fatty acid esters (e.g., glyceryl monostearate, glyceryl monooleate), sorbitan fatty acid esters (e.g., sorbitan monolaurate, sorbitan monostearate), and polyoxyethylene-polyoxypropylene block polymers.

[0156] Anionic surfactants (emulsifiers) may be carboxylates, sulfonates, sulfate esters, phosphate esters, etc. Examples of carboxylates include aliphatic monocarboxylic acids and alkyl ether carboxylates; examples of sulfonates include dialkyl sulfosuccinates, alkanesulfonates, alkylbenzenesulfonates, and alkylnaphthalenesulfonates; examples of sulfate esters include alkyl sulfates and oil sulfates; and examples of phosphate esters include alkyl phosphates and polyoxyethylene alkyl ether phosphates.

[0157] Cationic surfactants include amine salts, amidoamine salts, quaternary ammonium salts, and imidazolinium salts. Specific examples, though not particularly limited, include alkylamine salts, polyoxyethylene alkylamine salts, alkylamidoamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt-type surfactants such as imidazoline, alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, alkylpyridinium salts, alkylisoquinolinium salts, and quaternary ammonium salt-type surfactants such as benzethonium chloride.

[0158] Examples of amphoteric surfactants include alkylamine oxides, alanines, imidazolinium betaines, amide betaines, and acetate betaine. Specifically, examples include long-chain amine oxides, lauryl betaine, stearyl betaine, laurylcarboxymethylhydroxyethylimidazolinium betaine, lauryldimethylaminoacetic acid betaine, and fatty acid amidopropyldimethylaminoacetic acid betaine.

[0159] [Hydrophilic polymer] In one embodiment, the dispersant is preferably a hydrophilic polymer. In one embodiment, the hydrophilic polymer is a polymer having a hydrophilic group selected from the group consisting of hydroxyl groups, carboxyl groups, amino groups, ammonium groups, sulfonic acid groups, phosphate groups, etc. As the hydrophilic polymer, one or more can be selected from the group consisting of cellulose derivatives (hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, etc.), polyalkylene glycol, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, carboxyvinyl polymer, cationized guar gum, water-soluble polyurethane, polymers containing quaternary ammonium salt structures, amides, amines, etc. Among these, cellulose derivatives and polyalkylene glycols are more preferred, and polyalkylene glycols are particularly preferred.

[0160] The amount of dispersant in the resin composition is preferably 1 part by mass or more, or 3 parts by mass or more, or 5 parts by mass or more, or 10 parts by mass or more, or 15 parts by mass or more, per 100 parts by mass of cellulose nanofiber, and preferably 200 parts by mass or less, or 150 parts by mass or less, or 100 parts by mass or less, or 90 parts by mass or less, or 80 parts by mass or less, or 70 parts by mass or less, or 60 parts by mass or less, or 50 parts by mass or less.

[0161] The content of the dispersant in the resin composition components may, in one embodiment, be 0.1% by mass or more, or 0.5% by mass or more, or 1% by mass or more, and in one embodiment, it may be 40% by mass or less, or 35% by mass or less, or 30% by mass or less.

[0162] For example, when a preliminary composition containing cellulose nanofibers and an acid-modified styrene elastomer is used in the production of a resin composition, the mass ratio of the preliminary composition to the styrene elastomer (preliminary composition / styrene elastomer) in the resin composition components may, in one embodiment, be 1 / 99 to 99 / 1, or 5 / 95 to 95 / 5, or 10 / 90 to 90 / 10, or 20 / 80 to 80 / 20, or 30 / 70 to 70 / 30.

[0163] [Sulfurizing agents, sulfurization accelerators] When the resin composition components include liquid rubber, the resin composition components typically include a vulcanizing agent and may optionally include a vulcanization accelerator. Conventionally known vulcanizing agents and vulcanization accelerators may be appropriately selected depending on the type of liquid rubber in the resin composition components. Examples of vulcanizing agents include organic peroxides, azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur, and sulfur compounds. Examples of sulfur compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, and high-molecular-weight polysulfur compounds.

[0164] The amount of vulcanizing agent in the resin composition is preferably 0.01 to 20 parts by mass, or 0.1 to 15 parts by mass, per 100 parts by mass of liquid rubber in the resin composition.

[0165] Examples of vulcanization accelerators include sulfenamide-based, guanidine-based, thiuram-based, aldehyde-amine-based, aldehyde-ammonia-based, thiazole-based, thiourea-based, and dithiocarbamate-based vulcanization accelerators. Zinc oxide, stearic acid, etc., may also be used as vulcanization aids. The amount of vulcanization accelerator is preferably 0.01 to 20 parts by mass, or 0.1 to 15 parts by mass, per 100 parts by mass of liquid rubber in the resin composition.

[0166] [Rubber additive] The resin composition components may include various conventionally known rubber additives (stabilizers, softeners, antioxidants, etc.). As rubber stabilizers, one or more antioxidants such as 2,6-di-tert-butyl-4-hydroxytoluene (BHT), n-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenyl)propionate, and 2-methyl-4,6-bis[(octylthio)methyl]phenol may be used. As rubber softeners, one or more process oils, extender oils, etc., may be used. However, in one embodiment, the resin composition can form a flexible molded article, and therefore, in one embodiment, the resin composition components may not contain rubber softeners.

[0167] While vulcanizing agents, vulcanization accelerators, and rubber additives are typically added during the manufacturing of resin compositions, the manner of addition is not limited thereto.

[0168] <Additional components of the resin composition> The resin composition components may further contain additional components. Examples of additional components include additional polymers, organic or inorganic fillers, heat stabilizers, antioxidants, antistatic agents, colorants, etc. The content ratio of any additional component in the resin composition components is appropriately selected within a range that does not impair the desired effects of the present invention, but may be, for example, 0.01 to 50% by mass, or 0.1 to 30% by mass.

[0169] <Manufacturing of resin compositions> A resin composition according to one embodiment can be produced by mixing composition components which are a mixture containing cellulose nanofibers, an acid-modified styrene elastomer, and a styrene elastomer. A resin composition according to one embodiment can be produced by mixing a composition component which is a mixture containing a tack inhibitor containing cellulose nanofibers and a styrene-based elastomer. Mixing is, in one aspect, heating and kneading. In other words, a method for producing a resin composition according to one embodiment includes a kneading step of heating and kneading a mixture containing a styrene-based elastomer and cellulose nanofibers.

[0170] The weight increase rate of cellulose nanofibers after heating and kneading compared to cellulose nanofibers before heating and kneading is preferably 190% or more and 600% or less. From the viewpoint of interfacial strength between the resin and cellulose nanofibers, the weight increase rate is preferably 190% or more, or 250% or more, or 300% or more, or 350% or more, and from the viewpoint of suppressing short fiber formation during kneading, it is preferably 600% or less, or 550% or less, or 500% or less. The weight increase rate is a value measured by the method described in the [Examples] section of this disclosure.

[0171] As an example of a method for producing the resin composition, using an acid-modified styrene elastomer is as follows: (1) A first step of mixing cellulose nanofibers and an acid-modified styrene elastomer to obtain a preliminary composition, and A method comprising a second step of mixing the said pre-composition with a styrene-based elastomer to obtain a resin composition, (2) A method comprising the step of mixing together cellulose nanofibers, an acid-modified styrene elastomer, and a resin composition component containing a styrene elastomer. These are some examples. If an acid-modified styrene elastomer is not used, the resin composition components containing cellulose nanofibers and styrene elastomer may be mixed together in the method described in (2) above. The mixing conditions are not particularly limited, but for example, the components constituting the resin composition may be mixed using stirring means such as a rotation-orbit mixer, planetary mixer, propeller-type agitator, rotary agitator, electromagnetic agitator, open roll, Banbury mixer, kneader, single-screw extruder, or twin-screw extruder to obtain the resin composition. Alternatively, stirring may be performed under heating to efficiently carry out shearing. In the method described in (1) above, by combining the acid-modified styrene elastomer with cellulose nanofibers in advance, the contact opportunities between the cellulose nanofibers and the styrene elastomer become more appropriate and uniform, which can lead to better improvement in the physical properties of the resin composition.

[0172] The cellulose nanofibers used for mixing with acid-modified styrene elastomers or styrene elastomers may be in the form of a dried product containing cellulose nanofibers. In one embodiment, cellulose nanofibers may be mixed with a liquid polymer and / or dispersant in the form of a slurry, and the contained liquid medium may be dried and removed to obtain a dried product containing cellulose nanofibers. In this case, the drying process can be carried out, for example, as follows.

[0173] [Drying process] In one embodiment, a dried body containing cellulose nanofibers can be produced by drying a cellulose nanofiber slurry. Dryers are not limited to any particular type, but examples include kneaders, planetary mixers, Henschel mixers, high-speed mixers, propeller mixers, ribbon mixers, single-screw or twin-screw extruders, Banbury mixers, freeze dryers, shelf dryers, spray dryers, fluidized bed dryers, drum dryers, etc.

[0174] The drying temperature may be, for example, 20°C or higher, 30°C or higher, 40°C or higher, or 50°C or higher, from the viewpoint of forming a dried body containing cellulose nanofibers with excellent powder properties, such as drying efficiency, nanodispersibility of cellulose nanofibers in the resin composition, and macrodispersibility. From the viewpoint of minimizing thermal degradation of cellulose nanofibers and additional components, and from the viewpoint of avoiding excessive pulverization of the dried body containing cellulose nanofibers due to rapid drying of the slurry, the drying temperature may be, for example, 200°C or lower, 180°C or lower, 160°C or lower, 140°C or lower, 120°C or lower, or 100°C or lower. The drying temperature is the temperature of the heat source in contact with the slurry, and is defined, for example, as the surface temperature of the temperature-controlled jacket of the drying apparatus, the surface temperature of the heating cylinder, or the temperature of the hot air.

[0175] The pressure may be either atmospheric pressure or reduced pressure, but from the viewpoint of forming a dried body containing cellulose nanofibers with excellent powder properties such as drying efficiency, nanodispersibility of cellulose nanofibers in the resin composition, and macrodispersibility, it may be -1kPa or less, -10kPa or less, -20kPa or less, -30kPa or less, -40kPa or less, or -50kPa or less. From the viewpoint of avoiding excessive pulverization of the dried body containing cellulose nanofibers due to rapid drying of the slurry, it may be -100kPa or more, -95kPa or more, or -90kPa or more.

[0176] The concentration of cellulose nanofibers in the cellulose nanofiber slurry subjected to the drying process is preferably 1% by mass or more, or 2% by mass or more, or 3% by mass or more, or 5% by mass or more, or 10% by mass or more, or 15% by mass or more, or 20% by mass or more, or 25% by mass or more, from the viewpoint of process efficiency during drying. From the viewpoint of avoiding excessive increase in the viscosity of the slurry and solidification due to aggregation, and maintaining good handling properties, it is preferably 50% by mass or less, or 45% by mass or less, or 40% by mass or less, or 35% by mass or less. For example, cellulose nanofibers are often produced in a dilute dispersion, but the concentration of cellulose nanofibers in the slurry may be adjusted to the above preferred range by concentrating such a dilute dispersion. Methods such as suction filtration, pressure filtration, centrifugal deliquidation, and heating can be used for concentration.

[0177] In one embodiment, the dried product containing cellulose nanofibers may also contain a liquid polymer and / or a dispersant, which may be added before, during, and / or after drying the cellulose nanofiber slurry. In one embodiment, the liquid polymer and / or dispersant may be added in a dispersed or dissolved state in water and / or an organic solvent. The organic solvent is not particularly limited, but a solvent in which the liquid polymer and dispersant dissolve is preferred, and examples of water-insoluble solvents include chloroform, toluene, hexane, and cyclohexane.

[0178] [Liquid medium content] The liquid medium content of the dried product containing cellulose nanofibers is preferably 50% by mass or less, or 40% by mass or less, or 30% by mass or less, or 20% by mass or less, or 10% by mass or less, from the viewpoint of workability when kneading with acid-modified styrene-based elastomer or styrene-based elastomer. Particularly preferred liquid medium content from the viewpoint of tack suppression effect is 7% by mass or less, or 5% by mass or less, or 3% by mass or less. The liquid medium content may be 0% by mass, but from the viewpoint of ease of manufacturing the dried product containing cellulose nanofibers, it may be, for example, 0.1% by mass or more, or 1% by mass or more, or 1.5% by mass or more. The liquid medium content is a value measured using an infrared heating type moisture meter.

[0179] [Average particle size] In one embodiment, the average particle size of the dried material containing cellulose nanofibers is preferably 1 μm or more, or 10 μm or more, 50 μm or more, or 100 μm or more, or 200 μm or more, or 500 μm or more, from the viewpoint of ease of manufacture, and preferably 10,000 μm or less, or 5,000 μm or less, or 4,000 μm or less, or 3,000 μm or less, or 2,000 μm or less, from the viewpoint that the dried material containing cellulose nanofibers can easily disintegrate in the resin composition and the cellulose nanofibers can be well dispersed in the resin composition. The above average particle size is a value measured by a dynamic image analysis particle size distribution analyzer (CAMSIZER X2, manufactured by Microtrac).

[0180] [Loose bulk density] In one embodiment, the loosened bulk density of the dry material containing cellulose nanofibers is preferably 0.01 g / cm³, from the viewpoint of good fluidity and excellent feedability of the dry material containing cellulose nanofibers, and suppression of the transfer of liquid polymer and / or dispersant to the resin composition. 3 Above, or 0.05 g / cm³ 3 Above or equal to 0.10 g / cm³ 3 Above, or 0.15 g / cm³ 3 Above, or 0.20 g / cm³ 3 Above, or 0.25 g / cm³ 3 Above, or 0.30 g / cm³ 3or more, or 0.35 g / cm 3 or more, or 0.40 g / cm 3 or more, or 0.45 g / cm 3 or more, or 0.50 g / cm 3 or more, and the dried product containing cellulose nanofibers easily disintegrates in the resin composition and the cellulose nanofibers can be well dispersed in the resin composition, and the dried product containing cellulose nanofibers is not too heavy and can avoid poor mixing between the dried product containing cellulose nanofibers and the resin composition. Preferably, 0.85 g / cm 3 or less, or 0.80 g / cm 3 or less, or 0.75 g / cm 3 or less.

[0181] [Bulk density after compaction] In one aspect, the bulk density after compaction of the dried product containing cellulose nanofibers is controlled within a range useful for controlling the loose bulk density and the degree of compaction within the scope of the present disclosure. In one aspect, preferably, 0.01 g / cm 3 or more, or 0.1 g / cm 3 or more, or 0.15 g / cm 3 or more, or 0.2 g / cm 3 or more, or 0.3 g / cm 3 or more, or 0.4 g / cm 3 or more, or 0.5 g / cm 3 or more, or 0.6 g / cm 3 or more, and preferably, 0.95 g / cm 3 or less, or 0.9 g / cm 3 or less, or 0.85 g / cm 3 or less.

[0182] [Degree of compaction] The degree of compaction is a value calculated by Degree of compaction = (Bulk density after compaction - Loose bulk density) / Bulk density after compaction. The loose bulk density and the bulk density after compaction are values measured by the method described in the [Examples] section of the present disclosure. In one embodiment, the degree of compression represents the degree of bulk reduction. In one embodiment, the degree of compression of the dry material containing cellulose nanofibers is preferably 1% or more, or 5% or more, or 10% or more, or 15% or more, or 20% or more, or 25% or more, in that the fluidity of the dry material containing cellulose nanofibers is not too high. Furthermore, in terms of good fluidity and excellent feedability of the dry material containing cellulose nanofibers, excellent handling (specifically, less prone to scattering, floating, or dust formation), good dispersion of the dry material containing cellulose nanofibers in the resin composition, and suppression of the migration of the dispersant to the resin, the degree of compression is preferably 50% or less, or 45% or less, or 40% or less, or 35% or less, or 30% or less.

[0183] The above-mentioned loose bulk density, firm bulk density, and compressibility are measured using a powder tester (model number: PT-X) manufactured by Hosokawa Micron Corporation. The number of taps for firm bulk density measurement is 180.

[0184] As a more specific example of the process sequence, the following can be given when using an acid-modified styrene elastomer: (i) Prepare a slurry containing cellulose nanofibers and optionally a liquid polymer and / or a dispersant → Dry to prepare a dried product → Prepare a preliminary composition containing the dried product and an acid-modified styrene elastomer → Prepare a resin composition containing the preliminary composition and the styrene elastomer. (ii) Prepare a slurry containing cellulose nanofibers and optionally a liquid polymer and / or a dispersant → Dry to prepare a dried product → Prepare a preliminary composition containing the dried product and an acid-modified styrene elastomer and a styrene elastomer → Prepare a resin composition containing the preliminary composition and a styrene elastomer. (iii) Prepare a slurry containing cellulose nanofibers, an acid-modified styrene elastomer, and optionally a liquid polymer and / or a dispersant → Dry to prepare a dried product → Prepare a resin composition containing the dried product and the styrene elastomer. (iv) Prepare a slurry containing cellulose nanofibers, acid-modified styrene-based elastomer, styrene-based elastomer, and optionally a liquid polymer and / or a dispersant → Dry to prepare a resin composition

[0185] In addition, in the aspect of using a tack inhibitor containing cellulose nanofibers, the following can also be mentioned. (i) Prepare a slurry containing cellulose nanofibers and optionally a liquid polymer and / or a dispersant → Dry to prepare a dried product → Prepare a preliminary composition containing the dried product and an acid-modified styrene-based elastomer → Prepare a resin composition containing the preliminary composition and a styrene-based elastomer (ii) Prepare a slurry containing cellulose nanofibers and optionally a liquid polymer and / or a dispersant → Dry to prepare a dried product → Prepare a preliminary composition containing the dried product, an acid-modified styrene-based elastomer, and a styrene-based elastomer → Prepare a resin composition containing the preliminary composition and a styrene-based elastomer (iii) Prepare a slurry containing cellulose nanofibers and optionally a liquid polymer and / or a dispersant → Dry to prepare a dried product → Prepare a resin composition containing the dried product, an acid-modified styrene-based elastomer, and a styrene-based elastomer (iv) Prepare a slurry containing cellulose nanofibers, an acid-modified styrene-based elastomer, and optionally a liquid polymer and / or a dispersant → Dry to prepare a dried product → Prepare a resin composition containing the dried product and a styrene-based elastomer (v) Prepare a slurry containing cellulose nanofibers, an acid-modified styrene-based elastomer, a styrene-based elastomer, and optionally a liquid polymer and / or a dispersant → Dry to prepare a resin composition

[0186] A desired molded article may be produced by molding the resin composition alone or together with other components into a desired shape. The combination method of the blending components and the molding method are not particularly limited and may be selected according to the desired molded article. The molding is usually melt molding and may be carried out by injection molding, extrusion molding, extrusion profile molding, blow molding, compression molding, etc.

[0187] In one embodiment, the molding method may be for irregular shapes. That is, in one embodiment, the resin molded article of this embodiment may be an irregularly shaped article. Another aspect of the present invention provides a method for manufacturing an irregularly shaped extruded article, which includes a step of extruding the resin composition of this embodiment into an irregular shape. Known methods can be used for deformed extrusion molding. A specific example of a deformed extrusion molding method is a method in which a resin composition is put into an extruder, kneaded while being heated inside, and extruded from a die for deformed extrusion to obtain an uncooled resin molded body. Then, the uncooled resin molded body is continuously guided to a cooling zone and cooled to obtain a deformed extruded product.

[0188] Another method involves performing melt kneading to obtain a resin composition, extruding the die of the kneader as a die for deformed extrusion to obtain an uncooled resin molded body, and then continuously guiding the uncooled resin molded body to a cooling zone to cool it and obtain a deformed extruded product.

[0189] The lower limit of the extrusion temperature during shape extrusion is preferably +5°C relative to the melting point if the thermoplastic resin in the resin composition is a crystalline resin, and more preferably +10°C relative to the glass transition point if it is an amorphous resin. By controlling the lower limit within this range, the productivity of shape extrusion can be improved. The upper limit of the extrusion temperature during shape extrusion is preferably +100°C relative to the melting point if the thermoplastic resin in the resin composition is a crystalline resin, and more preferably +80°C, +70°C, and +60°C relative to the glass transition point if it is an amorphous resin. By controlling the upper limit within this range, the degradation of cellulose fine fibers can be suppressed, thus maintaining the mechanical properties of the resin composition, and the drawdown of the resin between the shape extrusion die and the cooling zone can be suppressed, resulting in good dimensional accuracy of the shape extruded molded product.

[0190] While there are no particular restrictions on the cross-sectional shape of the irregularly shaped extruded product, sheet-like, pipe-like, tubular, and angular shapes are preferred. In the case of a sheet shape, the sheet thickness can be 0.2 to 50 mm and the sheet width can be 10 to 1500 mm. In the case of a pipe-like or tubular shape, the thickness can be 0.1 to 30 mm and the inner diameter can be 1 to 1000 mm. In the case of an angular shape, the angle of the corner can be 30 to 150 degrees. The minimum radius of curvature on the valley side of the corner can be 0.1 mm.

[0191] <Materials for 3D printing> A preferred application of the resin composition of this embodiment is as a 3D printing material. One aspect of the present invention provides a 3D printing material comprising the resin composition of this embodiment. The 3D printing material may be molded into a desired form selected from various forms such as pellets, filaments, and powders. In one embodiment, the 3D printing material has the form of a filament or powder.

[0192] The 3D printing material of this embodiment is advantageous in that, due to its ability to suppress cellulose nanofiber aggregation, it suppresses liquid dripping (drawdown) from the nozzle due to its own weight during 3D printing.

[0193] Known methods can be used to mold a resin composition into a 3D printing material of a desired form. For example, the filament may be monofilament or multifilament, but monofilament is preferred due to its ease of molding.

[0194] The diameter of the filamentous material is preferably 0.5 to 5.0 mm, more preferably 1.0 to 3.5 mm, and most preferably 1.5 to 3.0 mm. The length of the filamentous material is preferably more than 1 m, more preferably more than 10 m, more preferably more than 100 m, and most preferably more than 300 m. By controlling the shape of the filamentous material within this range, a wide range of applicable 3D printers can be selected, and it becomes possible to appropriately design the printing time, the size of the printed object, and the level of detail. In one embodiment, the length of the filamentous material may be 20,000 m or less.

[0195] In one embodiment, the filamentous molding material can be manufactured by heating and melting a resin composition, passing it through a pore such as a nozzle, cooling it, and winding it up. The diameter of the pore can be appropriately selected according to the diameter of the filament and the winding speed, but from the viewpoint of manufacturing efficiency and the frequency of filament breakage defects, it is preferably 0.5 to 10.0 mm, more preferably 0.8 to 5.0 mm, and most preferably 1.0 to 3.0 mm. As for the cooling method, known methods such as air cooling and water cooling can be appropriately selected, but from the viewpoint of preventing water absorption due to the hydrophilicity of cellulose nanofibers, air cooling is preferred. From the viewpoint of manufacturing efficiency and the frequency of filament breakage defects, the winding speed of the filament is preferably 0.1 to 10 m / sec, more preferably 0.15 to 5 m / sec, and most preferably 0.2 to 1 m / sec. The manufacturing apparatus for the filamentous molding material and the manufacturing apparatus for the resin composition may be the same or different.

[0196] The particle size, particle shape, and aspect ratio of the powdered 3D printing material can be appropriately selected depending on the 3D printer used. In one embodiment, the particle size is preferably 1 to 10,000 μm, more preferably 10 to 500 μm, and most preferably 30 to 200 μm, from the viewpoint of handling as a 3D printing material and surface smoothness of the printed object. The particle shape may be spherical or irregular, but an irregular shape is preferred from the viewpoint of suppressing voids during printing. The aspect ratio is preferably 1.001 to 3.0, more preferably 1.01 to 2.0, and most preferably 1.1 to 1.8, from the viewpoint of suppressing voids by reducing the interparticle gaps.

[0197] In one embodiment, a powdered molding material can be produced by grinding or reprecipitating a resin composition. The method of grinding the resin composition is not particularly limited, but may include wet grinding, dry grinding, low-temperature grinding, freeze grinding, and heat grinding. A grinding medium may be used for the purpose of controlling the shape of the powdered molding material.

[0198] <Sculpture> One aspect of the present invention provides a molded object formed by 3D printing using a resin composition (e.g., resin composition pellets) or a 3D printing material according to this embodiment. Another aspect of the present invention also provides a method for manufacturing a molded object, which includes the step of 3D printing using a resin composition or a 3D printing material according to this embodiment. Examples of 3D printing methods include fused deposition modeling (FDM), stereolithography (SLA), material jetting, powder bonding, and powder bed fusion. When using a filamentous material, FDM is preferred, and when using a powdered material, powder bonding and powder bed fusion are preferred.

[0199] <Applications of 3D printing materials and printed objects> The molded object can be used as is for various applications, or it can be molded into a desired shape, either alone or in combination with other components, to produce a desired molded product. The method of combining components and the molding method are not particularly limited and may be selected according to the desired molded product. The molding method is not limited to these, but methods such as cutting molding and foam molding can be used. The molded object or molded product is useful as a substitute for steel plates, fiber-reinforced plastics (e.g., carbon fiber reinforced plastics, glass fiber reinforced plastics, etc.), resin composites containing inorganic fillers, etc. Suitable applications for 3D printing materials, molded objects, or molded products include industrial machine parts, general machine parts, automobile, railway, vehicle, ship, and aerospace-related parts, electronic and electrical components, building and civil engineering materials, household goods, sports and leisure goods, wind turbine housing components, containers and packaging components, etc.

[0200] The resulting molded products can be used for a variety of applications, including automotive parts, electrical and electronic components, building materials, household goods, cosmetic and medical components, rails, pipes, sashes, door frames, window frames, handrails, decking materials, fences, and various other building materials.

[0201] Specifically, automotive parts include interior components such as inner handles, fuel trunk openers, seat belt buckles, assist wraps, various switches, knobs, levers, and clips; electrical system components such as meters and connectors; in-vehicle electrical and electronic components such as audio equipment and car navigation equipment; metal-contacting components such as window regulator carrier plates; and mechanical components such as door lock actuator components, mirror components, wiper motor system components, and fuel system components.

[0202] Electrical and electronic components include parts or components of equipment made of resin molded bodies with numerous metal contacts, such as audio equipment, video equipment, or office automation equipment such as telephones, photocopiers, fax machines, word processors, and computers, as well as parts or components of toys. Specifically, these include chassis, gears, levers, cams, pulleys, and bearings.

[0203] Furthermore, it is suitably used for a wide range of living-related parts, cosmetic-related parts, and medical-related parts such as lighting fixtures, building fixtures, pipes, cocks, faucets, toilet peripheral equipment parts, etc. of building materials and piping parts, fasteners, stationery, lip cream and lipstick containers, cleaners, water purifiers, spray nozzles, spray containers, aerosol containers, general containers, and holders for injection needles.

[0204] Among these, it can be more preferably used for gears, which are applications placed in a high-temperature environment and subjected to a high load.

[0205] The tensile stress (modulus) (M100) at 100% elongation of the resin composition or resin molded body may be 2.0 MPa or more, or 3.0 MPa or more, or 4.0 MPa or more in one aspect, and may be 10.0 MPa or less, or 9.0 MPa or less, or 8.0 MPa or less in one aspect.

[0206] The tensile stress (M300) at 300% elongation of the resin composition or resin molded body may be 3.0 MPa or more, or 5.0 MPa or more, or 6.0 MPa or more in one aspect, and may be 20.0 MPa or less, or 15.0 MPa or less, or 13.0 MPa or less in one aspect.

[0207] The ratio (M300 / M100) of the tensile stress (M300) at 300% elongation to the tensile stress (M100) at 100% elongation of the resin composition or resin molded body may be 1.3 or more, or 1.4 or more, or 1.5 or more in one aspect, and may be 2.0 or less, or 1.8 or less in one aspect.

[0208] The storage elastic modulus of the resin composition or resin molded body may be 2.0 MPa or more, or 2.5 MPa or more in one aspect, and may be 4.0 MPa or less, or 3.5 MPa or less, or 3.0 MPa or less in one aspect.

[0209] The loss loss tangent of the resin composition or resin molded article may, in one embodiment, be 0.18 or less, or 0.15 or less, or 0.10 or less, and in one embodiment, it may be 0.02 or more, or 0.03 or more, or 0.04 or more. The above storage modulus and loss tangent are values ​​measured using a rheometer in a torsional manner at 50°C and 10Hz.

[0210] ≪Resin molded product≫ One aspect of the present invention provides a resin molded article obtained by molding the resin composition of this embodiment. The resin molded article may have various shapes. The molded article can be used in a wide range of applications, such as industrial machine parts, general machine parts, automobile, railway, vehicle, ship, and aerospace-related parts, electronic and electrical components, building and civil engineering materials, household goods, sports and leisure goods, wind turbine housing components, containers and packaging components, etc. Examples of applications include automotive parts (e.g., exterior parts such as tires, bumpers, fenders, door panels, various moldings, emblems, engine hoods, wheel caps, roofs, spoilers, and various aero parts, as well as interior parts such as instrument panels, console boxes, and trims), battery parts (automotive secondary battery parts, lithium-ion secondary battery parts, fuel cases for solid methanol batteries, fuel cell piping, etc.), electronic and electrical equipment parts (e.g., various computers and their peripherals, junction boxes, various connectors, various office automation equipment, televisions, video players, disc players, chassis, refrigerators, air conditioners, LCD projectors, etc.), household goods (shoe outsoles, etc.), vibration-damping rubber, conveyor belts, and other molded products.

[0211] This disclosure also includes the following items: ≪Item A≫ [Item 1] A resin composition comprising an acid-modified styrene elastomer, a styrene elastomer, and cellulose nanofibers, A resin composition in which the total amount of the acid-modified styrene elastomer and the styrene elastomer is 60% by mass or more of the resin composition as 100% by mass. [Item 2] The resin composition according to item 1, wherein the acid-modified styrene elastomer and the styrene elastomer are compatible. [Item 3] The resin composition according to item 1 or 2, comprising 0.5 to 50 parts by mass of the acid-modified styrene elastomer per 100 parts by mass of the styrene elastomer. [Item 4] A resin composition according to any one of items 1 to 3, comprising 0.5 to 250 parts by mass of the styrene-based elastomer per 1 part by mass of the cellulose nanofiber. [Item 5] A resin composition according to any one of items 1 to 4, comprising 0.5 to 45 parts by mass of the acid-modified styrene elastomer per 1 part by mass of the cellulose nanofiber. [Item 6] A resin composition according to any one of items 1 to 5, comprising 0.5% to 50% by mass of the acid-modified styrene elastomer. [Item 7] A resin composition according to any one of items 1 to 6, comprising the styrene-based elastomer in an amount of 10% to 98.8% by mass. [Item 8] A resin composition according to any one of items 1 to 7, comprising 0.1% to 20% by mass of the cellulose nanofibers. [Item 9] The resin composition according to any one of items 1 to 8, wherein the acid modification rate of the acid-modified styrene-based elastomer is 0.2% by mass to 2.5% by mass. [Item 10] The resin composition according to any one of items 1 to 9, wherein the styrene-based elastomer is an unmodified product. [Item 11] The resin composition according to any one of items 1 to 10, wherein the acid-modified styrene elastomer is an acid-modified product of a styrene elastomer that is an aromatic vinyl compound-conjugated diene compound block copolymer or a hydrogenated thereof. [Item 12] The resin composition according to any one of items 1 to 11, wherein the styrene-based elastomer is an aromatic vinyl compound-conjugated diene compound block copolymer or a hydrogenated thereof. [Item 13] The resin composition according to any one of items 1 to 12, wherein the melt mass flow rate of the styrene-based elastomer at 230°C and 2.16 kg is 20 g / 10 min or less. [Item 14] The resin composition according to any one of items 1 to 13, wherein the styrene unit ratio of the acid-modified styrene elastomer is 10% to 45% by mass. [Item 15] The resin composition according to any one of items 1 to 14, wherein the styrene unit ratio of the styrene-based elastomer is 10% to 45% by mass. [Item 16] The resin composition according to any one of items 1 to 15, wherein the ratio of the styrene unit ratio of the styrene-based elastomer to the styrene unit ratio of the acid-modified styrene-based elastomer (styrene ratio of the styrene-based elastomer / styrene ratio of the acid-modified styrene-based elastomer) is 0.3 to 2.5. [Item 17] The resin composition according to any one of items 1 to 16, wherein the number average molecular weight of the acid-modified styrene elastomer is 10,000 to 500,000, and the number average molecular weight of the styrene elastomer is 10,000 to 500,000. [Item 18] The resin composition according to any one of items 1 to 17, wherein the ratio of the styrene unit ratio to the acid modification rate (styrene unit ratio / acid modification rate) in the acid-modified styrene elastomer is 5 to 90. [Item 19] The resin composition according to any one of items 1 to 18, wherein the amount of acid-modified groups in the acid-modified styrene elastomer is 0.2% to 5.0% by mass, relative to 100% by mass of the cellulose nanofibers. [Item 20] The resin composition according to any one of items 1 to 19, wherein the number-average fiber diameter of the cellulose nanofibers is 2 nm to 1000 nm. [Item 21] The resin composition according to any one of items 1 to 20, wherein the thermal decomposition initiation temperature of the cellulose nanofiber is 250°C or higher. [Item 22] The specific surface area of ​​the cellulose nanofiber is 10 m². 2 / g~200m 2 A resin composition according to any of items 1 to 21, which is / g. [Item 23] A resin composition according to any one of items 1 to 22, further comprising a polyoxyethylene unit-containing polymer. [Item 24] A resin composition according to any one of items 1 to 23, further comprising a liquid polymer. [Item 25] A method for producing a resin composition as described in any of items 1 to 24, A method comprising heating and kneading a mixture containing the acid-modified styrene-based elastomer, the styrene-based elastomer, and the cellulose nanofiber. [Item 26] A resin molded article obtained by molding a resin composition described in any of items 1 to 24. [Item 27] A resin molded article as described in item 26, which is a deformed extruded product. [Item 28] A method for manufacturing a deformed extruded product, A method comprising the step of extruding a resin composition described in any of items 1 to 24 into a deformed shape. [Item 29] A 3D printing material comprising a resin composition described in any of items 1 to 24. [Item 30] A 3D printing material as described in item 29, having the form of a filament or powder. [Item 31] A shaped object formed by shaping the resin composition according to any one of Items 1 to 24 or the shaping material for 3D printing according to Item 29 or 30 using a 3D printer. [Item 32] A method for manufacturing a shaped object, The method includes a step of shaping the resin composition according to any one of Items 1 to 24 or the shaping material for 3D printing according to Item 29 or 30 using a 3D printer.

[0212] ≪Item B≫ [Item 1] A resin composition including a styrenic elastomer and a tack inhibitor including cellulose nanofibers. [Item 2] The resin composition according to Item 1, including 10% by mass or more of the styrenic elastomer. [Item 3] The resin composition according to Item 1 or 2, including 0.1% by mass to 20% by mass of the cellulose nanofibers. [Item 4] The resin composition according to any one of Items 1 to 3, further including an acid-modified styrenic elastomer. [Item 5] The resin composition according to any one of Items 1 to 4, wherein the styrenic elastomer is an unmodified product. [Item 6] The resin composition according to any one of Items 1 to 5, including 0.5 parts by mass to 250 parts by mass of the styrenic elastomer with respect to 1 part by mass of the cellulose nanofibers. [Item 7] The resin composition according to any one of Items 1 to 6, wherein the styrenic elastomer is an aromatic vinyl compound-conjugated diene compound block copolymer or a hydrogenated product thereof. [Item 8] The resin composition according to any one of Items 1 to 7, wherein the MFR of the styrenic elastomer at 230 °C and 2.16 kg is 20 g / 10 min or less. [Item 9] The resin composition according to any one of items 1 to 8, wherein the styrene unit ratio of the styrene-based elastomer is 10 mol% to 40 mol%. [Item 10] The resin composition according to any one of items 1 to 9, wherein the number average molecular weight of the styrene-based elastomer is 10,000 to 500,000. [Item 11] The resin composition according to any one of items 1 to 10, wherein the number-average fiber diameter of the cellulose nanofibers is 2 nm to 1000 nm. [Item 12] The resin composition according to any one of items 1 to 11, wherein the thermal decomposition initiation temperature of the cellulose nanofiber is 250°C or higher. [Item 13] The specific surface area of ​​the cellulose nanofiber is 10 m². 2 / g~200m 2 A resin composition according to any of items 1 to 12, which is / g. [Item 14] A resin composition according to any one of items 1 to 13, further comprising a dispersant. [Item 15] The resin composition according to item 14, wherein the dispersant is a polyoxyethylene unit-containing polymer. [Item 16] A resin composition according to any one of items 1 to 15, further comprising a liquid polymer. [Item 17] A method for producing a resin composition as described in any of items 1 to 16, A method comprising a kneading step of heating and kneading a mixture containing a styrene-based elastomer and cellulose nanofibers. [Item 18] The method according to item 17, wherein the cellulose nanofibers subjected to the kneading step are a dry body with a liquid medium content of 7% by mass or less. [Item 19] A resin molded article obtained by molding a resin composition described in any of items 1 to 16. [Item 20] A resin molded product as described in item 19, which is a deformed extruded product. [Item 21] A method for manufacturing a deformed extruded product, A method comprising the step of extruding a resin composition described in any of items 1 to 16 into a deformed shape. [Item 22] A 3D printing material comprising a resin composition described in any of items 1 to 16. [Item 23] A 3D printing material as described in item 22, having the form of a filament or powder. [Item 24] A molded object produced by 3D printing using a resin composition described in any of items 1 to 16 or a 3D printing material described in item 22 or 23. [Item 25] A method for manufacturing a molded object, A method comprising the step of fabricating a resin composition described in any of items 1 to 16 or a 3D printing material described in item 22 or 23 using a 3D printer. [Examples]

[0213] The following describes illustrative embodiments of the present invention with reference to examples, but the present invention is not limited to these examples.

[0214] ≪Evaluation Method≫ <Acid-modified styrene elastomers and styrene elastomers> [Acid denaturation rate (maleination rate)] The values ​​shown are from the product catalog.

[0215] [Styrene unit ratio] The values ​​shown are from the product catalog.

[0216] [MFR at 230℃, 2.16kg] The values ​​shown are from the product catalog.

[0217] <Liquid polymer> [Viscosity at 25°C] The viscosity of the rubber was measured using a Type B viscometer.

[0218] <Cellulose nanofiber> The following evaluations were conducted on cellulose nanofibers. [Fabrication of porous sheets] First, the concentrated cake was added to tert-butanol and then dispersed using a mixer or similar device until no aggregates remained. The concentration was adjusted to 0.5% by mass for every 0.5 g of cellulose nanofiber solids. 100 g of the resulting tert-butanol dispersion was filtered on filter paper. The filtrate was not removed from the filter paper, but sandwiched between two larger sheets of filter paper, and the edges of the larger sheets were pressed down with weights while drying in a 150°C oven for 5 minutes. After that, the filter paper was peeled off to obtain a porous sheet with minimal distortion. The air permeability resistance of this sheet was 10 g / m². 2 Porous sheets with a flow rate of 100 sec / 100 ml or less were used as measurement samples. The basis weight (W) of the sample after standing for 1 day in an environment of 23℃ and 50%RH (g / m²) 2 After measuring the air permeability resistance (R) (sec / 100ml), the air permeability resistance was measured using a Wangyan-type air permeability resistance tester (manufactured by Asahi Seiko Co., Ltd., model EG01). At this time, 10 g / m was measured according to the following formula. 2 The value per unit area was calculated. Weight: 10g / m 2 Air permeability resistance (sec / 100ml) = R / W × 10

[0219] [Weight-average molecular weight (Mw), number-average molecular weight (Mn), and Mw / Mn ratio] 0.88 g of porous sheet was weighed, cut into small pieces with scissors, lightly stirred, and then 20 mL of pure water was added and left for 1 day. Next, the water and solids were separated by centrifugation. Then 20 mL of acetone was added, lightly stirred, and left for 1 day. Next, the acetone and solids were separated by centrifugation. Then 20 mL of N,N-dimethylacetamide was added, lightly stirred, and left for 1 day. After separating the N,N-dimethylacetamide and solids again by centrifugation, 20 mL of N,N-dimethylacetamide was added, lightly stirred, and left for 1 day. The N,N-dimethylacetamide and solids were separated by centrifugation, and 19.2 g of N,N-dimethylacetamide solution, prepared so that lithium chloride was 8 mass percent, was added to the solids, stirred with a stirrer, and visually confirmed to be dissolved. The solution containing dissolved cellulose nanofibers was filtered through a 0.45 μm filter, and the filtrate was used as a sample for gel permeation chromatography. The equipment and measurement conditions used are as follows. Equipment: Tosoh Corporation HLC-8120 Column: TSKgel SuperAWM-H (6.0mm I.D. × 15cm) × 2 tubes Detector: RI detector Eluent: N,N-dimethylacetamide (lithium chloride 0.2%) Flow rate: 0.6mL / min Calibration curve: Pullulan equivalent

[0220] [Average content of alkali-soluble polysaccharides] The alkali-soluble polysaccharide content was determined for cellulose nanofibers by subtracting the α-cellulose content from the holocellulose content (Wise method), using the method described in the non-patent literature (Wood Science Experiment Manual, edited by the Japan Wood Research Society, pp. 92-97, 2000). The alkali-soluble polysaccharide content was calculated three times for each sample, and the number average of the calculated alkali-soluble polysaccharide content was taken as the average alkali-soluble polysaccharide content of the cellulose nanofibers.

[0221] [Average content of acid-insoluble components] The acid-insoluble components were quantified using the Claesson method described in a non-patent document (Wood Science Experiment Manual, edited by the Japan Wood Research Society, pp. 92-97, 2000) for cellulose nanofibers. Absolutely dried cellulose nanofibers were accurately weighed, placed in a designated container, and 72% by mass concentrated sulfuric acid was added. After pressing the contents uniformly with a glass rod, the mixture was autoclaved to dissolve the cellulose and hemicellulose in the acid solution. After cooling, the contents were filtered through glass fiber filter paper to obtain the acid-insoluble components as a residue. The acid-insoluble component content was calculated from the weight of this residue, and the number average of the acid-insoluble component content calculated for three samples was taken as the average acid-insoluble component content.

[0222] [Crystallization] X-ray diffraction measurements were performed on the porous sheet, and the degree of crystallinity was calculated using the following formula. Crystallinity (%)=[I (200) -I (amorphous) ] / I (200) ×100 I (200) :Diffraction peak intensity at the 200 plane (2θ=22.5°) in cellulose type I crystals I (amorphous) : The halo peak intensity due to amorphous material in type I cellulose crystals, specifically the peak intensity at an angle 4.5° lower than the diffraction angle of the 200 plane (2θ = 18.0°). (X-ray diffraction measurement conditions) MiniFlex device (manufactured by Rigaku Corporation) Operation axis 2θ / θ Source CuKα Measurement method: Continuous Voltage 40kV Current 15mA Starting angle 2θ=5° Ending angle 2θ = 30° Sampling width 0.020° Scan speed 2.0° / min Sample: A porous sheet is attached to the sample holder.

[0223] [Number average fiber diameter] The concentrated cake was diluted with tert-butanol to 0.01% by mass, dispersed using a high-shear homogenizer (IKA, product name "Ultra-Turrax T18") under the following conditions: rotation speed 15,000 rpm for 3 minutes, cast onto an osmium-deposited silicon substrate, and air-dried. The resulting material was then measured using a high-resolution scanning electron microscope (Hitachi High-Tech Corporation, Regulus 8220). The measurement was performed by adjusting the magnification so that at least 100 cellulose nanofibers could be observed. The diameter (D) of 100 randomly selected cellulose nanofibers was measured, and the number-average fiber diameter was calculated by averaging the values ​​of these 100 cellulose nanofibers.

[0224] [Aspect Ratio] The number-average fiber length L, number-average fiber diameter D, and number-average aspect ratio (L / D) of cellulose nanofibers in a resin composition are measured using an optical microscope according to the following procedure. A resin composition prepared by heating and kneading resin and cellulose nanofibers was used as a measurement sample, and the cellulose nanofibers in the resin were measured with an optical microscope while heating to 220°C on a hot stage. Specifically, the length and diameter of 200 randomly selected cellulose nanofibers were measured, and the ratio was calculated. Then, the number-average values ​​of each were used as the number-average fiber length L and number-average fiber diameter D, and the number-average aspect ratio (L / D) was calculated.

[0225] [Specific surface area] Using a specific surface area and pore distribution analyzer (Nova-4200e, manufactured by Quantachrome Instruments), approximately 0.2 g of a porous sheet was dried under vacuum at 120°C for 5 hours. Then, the amount of nitrogen gas adsorbed at the boiling point of liquid nitrogen was measured at 5 points within a relative vapor pressure (P / P0) range of 0.05 to 0.2 (multi-point method). The BET specific surface area (m²) was then calculated using the analyzer's program. 2 The value per gram ( / g) was calculated.

[0226] [Thermal decomposition onset temperature (T D )] Thermal analysis of the porous sheet was performed using the following measurement method. Device: Rigaku Thermo plus EVO2 Sample: Circular pieces cut from a porous sheet were stacked in aluminum sample pans, with 10 mg of each piece placed on top. Sample amount: 10 mg Measurement conditions: The temperature was increased from room temperature to 150°C at a rate of 10°C / min in a nitrogen flow of 100 ml / min, held at 150°C for 1 hour, and then continued to increase to 450°C at a rate of 10°C / min. T D Calculation Method: The temperature was determined from a graph with temperature on the horizontal axis and weight retention percentage on the vertical axis. Starting from the weight of the porous sheet at 150°C (when moisture is almost completely removed) (weight loss of 0 wt%), the temperature was further increased, and a straight line was obtained that passes through the temperature at which the weight decreased by 1 wt% and the temperature at which the weight decreased by 2 wt%. The temperature at the point where this straight line intersects with the horizontal line (baseline) passing through the starting point of 0 wt% weight loss was defined as the thermal decomposition onset temperature (T D )

[0227] [1wt% weight loss temperature] Said T D The temperature at which a 1 wt% weight loss occurred during the calculation was defined as the 1 wt% weight loss temperature.

[0228] [250℃ weight loss rate] Device: Rigaku Thermo plus EVO2 Sample: Circular pieces cut from a porous sheet were stacked in aluminum sample pans, with 10 mg of each piece placed on top. Sample amount: 10 mg Measurement conditions: The temperature was raised from room temperature to 150°C at a rate of 10°C / min in a nitrogen flow of 100 ml / min, held at 150°C for 1 hour, then raised from 150°C to 250°C at a rate of 10°C / min, and held at 250°C for 2 hours. The weight W0 at the time of reaching 250°C was used as the starting point, and the weight after holding at 250°C for 2 hours was defined as W1, which was calculated using the following formula. 250℃ weight loss rate (%): (W0-W1) / W0}×100

[0229] [Weight increase rate of cellulose nanofibers separated from resin composition using THF] Separating cellulose nanofibers from a resin composition can be easily carried out by a method common to those skilled in the art. The separation was performed by the following method. Using about 1.5 g of fragments of the resin composition, the resin fragments were dissolved in 70 ml of THF and separated into a soluble component (resin) and an insoluble component (cellulose nanofibers and resin adsorbed on the fiber surface). After filtering the insoluble component with filter paper, it was dried in a vacuum dryer at 80 °C for 3 hours for concentration, and the weight of the insoluble component was measured. The weight increase rate of the cellulose nanofibers was calculated from the following formula. The theoretical weight below is the charged weight of the cellulose nanofibers. Weight increase rate of cellulose nanofibers (%) = (weight of insoluble component - theoretical weight of cellulose nanofibers contained in the fragments) ÷ theoretical weight of cellulose nanofibers contained in the fragments × 100

[0230] <Resin composition> [Degree of whitening (void amount) at breakage] Using the test piece after the test by the tensile test method of JIS K-6251, the breakage location (2 mm in the ND direction × 3 mm in the TD direction × 4 mm in the MD direction) was observed for the MD / TD direction cross-section using X-ray CT. Device: Bruker X-CT Skyscan1272 <Conditions> Tube voltage: 40 kV, tube current: 100 μA, number of pixels: 2k (2452 × 1640 pix), pixel resolution: 2.4 μm, number of integration times: 4 times, scan: every 0.4°, analysis process: smoothing (Kuwahara filter 2 pix) Next, binarization processing of the observed image was performed to extract void locations, and the ratio (%) of the total volume of voids per unit volume was quantified.

[0231] (Binarization conditions for void locations) Binarization 0 - 35 (global range: 0 - 255), removal of objects of 4 voxels or less, and objects of 50 pixels or more in the xy cross-section are regarded as foreign substances or artifacts derived therefrom and removed (Evaluation criteria) Defective: 1% or more Acceptable: 0.5% or more and less than 1% Good: 0.02% or higher, less than 0.5% Excellent: Less than 0.02%

[0232] [Tensile stress at 400% strain, tensile modulus of elasticity at 50-100% strain, maximum tensile stress, strain] According to the tensile test method of JIS K-6251, tensile strength, tensile stress at 50% elongation (50% modulus), tensile stress at 100% elongation (100% modulus), and tensile stress at 400% elongation (400% modulus) were measured, and the tensile stress at 400% strain, the tensile modulus of elasticity at 50-100% strain (the value obtained by dividing the increment of 100% modulus relative to 50% modulus by the strain increment (100%-50%)), the maximum tensile stress, and the strain at fracture were determined.

[0233] [Colorability] The color of the molded dumbbells was visually evaluated. (Evaluation Criteria) Defective: Caramel color Available: Light caramel color Good: Milky white Superior: White or transparent

[0234] [Surface fuzziness of the strand] The surface condition of the extruded strands was visually evaluated. (Evaluation Criteria) Defective: The surface is uneven with no smooth areas and has many irregularities. Acceptable: A surface condition in which smooth areas and uneven areas exist in roughly equal proportions. Good: Surface condition with slight fuzzing visible on the surface. Excellent: Surface condition with absolutely no fuzz or lint.

[0235] [Tuckability] The tack strength was measured using a TAC-II tacking tester manufactured by Resca Corporation. The measurement mode used was Constant Load, which involves pushing the probe in to a set pressure value and continuously controlling the system to maintain that pressure value until a set time has elapsed. Specifically, the area is 19.625 mm². 2A stainless steel probe with a flat surface was brought into contact with the surface of the sample under the following conditions: probe movement speed: 120 mm / min, applied pressure (load): 600 gf, and pressurization time: 60 seconds. The probe was then pulled upwards at a probe movement speed (detachment speed): 600 mm / min. The tack peak value on the surface of the resin composition was measured 10 times using a probe tack test, and the tack strength was defined as the average value of the 10 measurements divided by the area of ​​the probe's flat surface. The measurements were performed at 23°C.

[0236] [Tensile stress, maximum tensile stress, and strain at 400% strain] Tensile tests were performed using ISO 37 type 3 specimens at a temperature of 23°C and a relative humidity of 50% at a tensile speed of 5 mm / min. The arithmetic mean of five data points—tensile stress at 400% strain, maximum tensile stress, and strain at fracture—was calculated.

[0237] ≪Materials used≫ <Styrene-based elastomer> SEBS, manufactured by Asahi Kasei Corporation, ToughTec H1062, MFR: 4.1g / 10min (230℃, 2.16kg)

[0238] <Acid-modified styrene elastomer> Acid-modified styrene elastomer 1: Maleic acid-modified SEBS, manufactured by Asahi Kasei Corporation, ToughTec M1943, MFR: 6.5g / 10min (230℃・2.16kg) Acid-modified styrene elastomer 2: Maleic acid-modified SEBS, manufactured by Asahi Kasei Corporation, ToughTec M1913, MFR: 6.5g / 10min (230℃·2.16kg) Acid-modified styrene elastomer 3: Maleic acid-modified SEBS, manufactured by Asahi Kasei Corporation, ToughTec M1911, MFR: 4.2g / 10min (230℃·2.16kg)

[0239] <Cellulose nanofiber (unmodified CNF)> 3 parts by mass of cotton linter pulp was immersed in 27 parts by mass of water and dispersed with a pulper. 170 parts by mass of water was added to 30 parts by mass of the cotton linter pulp slurry (including 3 parts by mass of cotton linter pulp) treated with the pulper and dispersed in water (solid content rate: 1.5% by mass). Using an SDR14 type laboratory refiner (pressure type DISK type) manufactured by Aikawa Iron Works Co., Ltd. as a disk refiner device, with the clearance between the disks set to 1 mm, the aqueous dispersion was subjected to beating treatment for 30 minutes. Subsequently, beating was thoroughly performed under the condition of reducing the clearance to a level close to almost zero, and a beaten aqueous dispersion (solid content concentration: 1.5% by mass) was obtained. The obtained beaten aqueous dispersion was directly subjected to 10 times of micronization treatment using a high-pressure homogenizer (NSO15H manufactured by Niro Soavi, Italy) under an operating pressure of 100 MPa to obtain a cellulose nanofiber slurry (solid content concentration: 1.5% by mass). Then, it was concentrated to a solid content rate of 10% by mass using a dehydrator to obtain a cake of cellulose nanofibers. The property values of the cellulose nanofibers are as follows. Weight average molecular weight (Mw): 380,000 Number average molecular weight (Mn): 80,000 Average content rate of alkali-soluble polysaccharides: 3.8% Average content rate of acid-insoluble components: 3.1% Crystallinity: 85% Number average fiber diameter: 75 nm Specific surface area: 34 m 2 / g Thermal decomposition start temperature (T D ): 283 °C 1 wt% weight loss temperature: 297 °C <000129​​​​​​​​​​​​​​​​Manufacturing of resin compositions <Example 1> Cellulose nanofiber cake, RICON 184, and PEG6000 were blended in a solid weight ratio of 7:4:3 and stirred in a Kodaira Seisakusho Co., Ltd. planetary mixer (model: ACM-5LVT: paddle type) under the conditions of a jacket temperature of 80°C and 307 rpm, while the pressure was reduced to -90 kPa with a vacuum pump. Vacuum drying was carried out until the product temperature reached 70°C to obtain cellulose nanofiber powder. The obtained cellulose nanofiber powder, SEBS, and acid-modified styrene elastomer 1 were blended in the proportions shown in Table 1 and melted for 5 minutes at 200°C and 200 rpm using a batch-type twin-screw kneader (DSM Explore). Test specimens (ISO 37 type 3) were prepared using a dedicated tabletop injection molding machine (DSM) at a mold temperature of 80°C.

[0243] <Examples 2-11, Comparative Examples 1-3> A resin composition was obtained in the same manner as in Example 1, except that the formulation was changed as shown in Table 1.

[0244] [Table 1] [Industrial applicability]

[0245] The resin composition relating to this disclosure can form molded articles with good physical properties and can therefore be suitably applied to a wide range of applications, such as industrial machine parts, general machine parts, automobile, railway, vehicle, ship, and aerospace-related parts, electronic and electrical components, building and civil engineering materials, household goods, sports and leisure goods, wind turbine housing components, containers and packaging components, etc.

Claims

1. A resin composition comprising a thermoplastic elastomer and cellulose nanofibers, The thermoplastic elastomer comprises an acid-modified styrene elastomer and a styrene elastomer. A resin composition in which the amount of the thermoplastic elastomer is 60% by mass or more in 100% by mass of the resin composition.

2. A resin composition comprising a thermoplastic elastomer and cellulose nanofibers, The number-average aspect ratio, which is the ratio L / D of the number-average fiber length L to the number-average fiber diameter D of the cellulose nanofibers in the resin composition, is 2 or more and 26 or less. A resin composition in which the amount of the thermoplastic elastomer is 60% by mass or more in 100% by mass of the resin composition.

3. A resin composition comprising a thermoplastic elastomer and cellulose nanofibers, When the cellulose nanofibers were separated from the resin composition using tetrahydrofuran (THF), the weight increase rate of the cellulose nanofibers was 190% to 600%. A resin composition in which the amount of the thermoplastic elastomer is 60% by mass or more in 100% by mass of the resin composition.

4. The resin composition includes, as the thermoplastic elastomer, an acid-modified styrene elastomer and a styrene elastomer. The resin composition according to any one of claims 1 to 3, wherein the total amount of the acid-modified styrene elastomer and the styrene elastomer in 100% by mass of the resin composition is 60% by mass or more.

5. The resin composition includes, as the thermoplastic elastomer, an acid-modified styrene elastomer and a styrene elastomer. The resin composition according to any one of claims 1 to 3, wherein the acid-modified styrene elastomer and the styrene elastomer are compatible.

6. The resin composition includes, as the thermoplastic elastomer, an acid-modified styrene elastomer and a styrene elastomer. The resin composition according to any one of claims 1 to 3, wherein the amount of the acid-modified styrene elastomer is 0.5 to 50 parts by mass per 100 parts by mass of the styrene elastomer.

7. The resin composition includes a styrene-based elastomer as the thermoplastic elastomer, The resin composition according to any one of claims 1 to 3, wherein the amount of the styrene-based elastomer is 0.5 to 250 parts by mass per 1 part by mass of the cellulose nanofiber.

8. The resin composition includes an acid-modified styrene-based elastomer as the thermoplastic elastomer. The resin composition according to any one of claims 1 to 3, wherein the amount of the acid-modified styrene elastomer is 0.5 to 45 parts by mass per 1 part by mass of the cellulose nanofiber.

9. The resin composition includes an acid-modified styrene-based elastomer as the thermoplastic elastomer. The resin composition according to any one of claims 1 to 3, wherein the amount of the acid-modified styrene elastomer is 0.5% to 50% by mass in 100% by mass of the resin composition.

10. The resin composition includes a styrene-based elastomer as the thermoplastic elastomer, The resin composition according to any one of claims 1 to 3, wherein the amount of the styrene-based elastomer in 100% by mass of the resin composition is 10% by mass to 98.8% by mass.

11. The resin composition according to any one of claims 1 to 3, comprising 0.1% to 20% by mass of the cellulose nanofibers.

12. The resin composition includes an acid-modified styrene-based elastomer as the thermoplastic elastomer. The resin composition according to any one of claims 1 to 3, wherein the acid modification rate of the acid-modified styrene-based elastomer is 0.2% by mass to 2.5% by mass.

13. The resin composition includes a styrene-based elastomer as the thermoplastic elastomer, The resin composition according to any one of claims 1 to 3, wherein the styrene-based elastomer is an unmodified product.

14. The resin composition includes an acid-modified styrene-based elastomer as the thermoplastic elastomer. The resin composition according to any one of claims 1 to 3, wherein the acid-modified styrene elastomer is an acid-modified product of a styrene elastomer which is an aromatic vinyl compound-conjugated diene compound block copolymer or a hydrogenated product thereof.

15. The resin composition includes a styrene-based elastomer as the thermoplastic elastomer, The resin composition according to any one of claims 1 to 3, wherein the styrene-based elastomer is an aromatic vinyl compound-conjugated diene compound block copolymer or a hydrogenated product thereof.

16. The resin composition includes a styrene-based elastomer as the thermoplastic elastomer, The resin composition according to any one of claims 1 to 3, wherein the melt mass flow rate of the styrene-based elastomer at 230°C and 2.16 kg is 20 g / 10 min or less.

17. The resin composition includes an acid-modified styrene-based elastomer as the thermoplastic elastomer. The resin composition according to any one of claims 1 to 3, wherein the styrene unit ratio of the acid-modified styrene elastomer is 10% by mass to 45% by mass.

18. The resin composition includes a styrene-based elastomer as the thermoplastic elastomer, The resin composition according to any one of claims 1 to 3, wherein the styrene unit ratio of the styrene-based elastomer is 10% by mass to 45% by mass.

19. The resin composition includes, as the thermoplastic elastomer, an acid-modified styrene elastomer and a styrene elastomer. The resin composition according to any one of claims 1 to 3, wherein the ratio of the styrene unit ratio of the styrene-based elastomer to the styrene unit ratio of the acid-modified styrene-based elastomer (styrene ratio of the styrene-based elastomer / styrene ratio of the acid-modified styrene-based elastomer) is 0.3 to 2.

5.

20. The resin composition includes, as the thermoplastic elastomer, an acid-modified styrene elastomer and a styrene elastomer. The resin composition according to any one of claims 1 to 3, wherein the number average molecular weight of the acid-modified styrene elastomer is 10,000 to 500,000, and the number average molecular weight of the styrene elastomer is 10,000 to 500,000.

21. The resin composition includes an acid-modified styrene-based elastomer as the thermoplastic elastomer. The resin composition according to any one of claims 1 to 3, wherein the ratio of the styrene unit ratio to the acid modification rate (styrene unit ratio / acid modification rate) in the acid-modified styrene elastomer is 5 to 90.

22. The resin composition includes an acid-modified styrene-based elastomer as the thermoplastic elastomer. The resin composition according to any one of claims 1 to 3, wherein the amount of acid-modified groups in the acid-modified styrene elastomer is 0.2% to 5.0% by mass, relative to 100% by mass of the cellulose nanofibers.

23. The resin composition according to any one of claims 1 to 3, wherein the number-average fiber diameter of the cellulose nanofibers is 2 nm to 1000 nm.

24. The resin composition according to any one of claims 1 to 3, wherein the thermal decomposition initiation temperature of the cellulose nanofiber is 250°C or higher.

25. The specific surface area of ​​the cellulose nanofiber is 10 m². 2 / g to 200m 2 The resin composition according to any one of claims 1 to 3, wherein the weight is / g.

26. The resin composition according to any one of claims 1 to 3, further comprising a polyoxyethylene unit-containing polymer.

27. A resin composition according to any one of claims 1 to 3, further comprising a liquid polymer.

28. A method for producing a resin composition according to any one of claims 1 to 3, The resin composition includes, as the thermoplastic elastomer, an acid-modified styrene elastomer and a styrene elastomer. A method comprising heating and kneading a mixture containing the acid-modified styrene-based elastomer, the styrene-based elastomer, and the cellulose nanofiber.

29. The method according to claim 28, wherein the weight increase rate of the cellulose nanofibers after heating and kneading compared to the cellulose nanofibers before heating and kneading is 190% to 600%.

30. A resin molded article obtained by molding a resin composition according to any one of claims 1 to 3.

31. A resin molded article according to claim 30, which is a deformed extruded product.

32. A method for manufacturing a deformed extruded product, A method comprising the step of extruding a resin composition according to any one of claims 1 to 3 into a deformed shape.

33. A 3D printing material comprising the resin composition described in any one of claims 1 to 3.

34. A 3D printing material according to claim 33, having the form of a filament or powder.

35. A molded object obtained by 3D printing a resin composition according to any one of claims 1 to 3.

36. A molded object formed by 3D printing using the 3D printing material described in claim 33.

37. A method for manufacturing a molded object, A method comprising the step of fabricating a resin composition according to any one of claims 1 to 3 using a 3D printer.

38. A method for manufacturing a molded object, A method comprising the step of fabricating a 3D printing material according to claim 33 using a 3D printer.

39. A resin composition comprising a styrene-based elastomer and a tack inhibitor containing cellulose nanofibers.

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