Resin composition

Abstract

The present invention provides, each as one embodiment: a resin composition capable of forming a resin molded body which has excellent tensile strength, tensile elastic modulus, and / or tensile elongation at break and in which impairments such as whitening and coloring hardly occur, while exhibiting advantageous properties inherent to a styrene-based elastomer (good rubber elasticity, weather resistance, chemical resistance, etc.); a method for producing the resin composition; and a molded body obtained by molding the resin composition. As one embodiment, provided is a resin composition which contains thermoplastic elastomers and cellulose nanofibers, and in which the thermoplastic elastomers include an acid-modified styrene-based elastomer and a styrene-based elastomer, and the amount of the thermoplastic elastomers is 60 mass% or more in 100 mass% of the resin composition.

Description

resin composition

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

[0002] Thermoplastic elastomers have been used in a wide range of applications because they exhibit rubber elasticity and can be melt-molded using techniques similar to those of thermoplastic resins. Known thermoplastic elastomers include styrene-based, olefin-based, polyurethane-based, polyester-based, polyamide-based, acrylic-based, and polyvinyl chloride-based elastomers. Among these, styrene-based elastomers have been used in sealing materials and the like due to their excellent weather resistance and chemical resistance, and have also been used as modifiers and additives for various materials.

[0003] Resin molded products are required to have a high level of balance among various properties desired depending on the application, such as mechanical strength, flexibility, abrasion resistance, and processability. To improve these properties, it is common practice to incorporate a filler into the resin molded product. In recent years, with growing awareness of environmental issues, various efforts have been made to use cellulose, a low-density, renewable material, as a filler to be incorporated into resin molded products. Among these, cellulose nanofibers are extremely promising as a filler for resin molded products because of the excellent reinforcing effect they provide per unit amount when combined with various resins to form the resin molded product.

[0004] Patent Document 1 describes a resin composition containing 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 containing 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 elastomer are phase-separated, and more than 50% by mass of the cellulose is present in the polyamide phase.

[0005] JP 2020-029488 A JP 2022-007985 A

[0006] Among resin molded articles, for example, those primarily composed of styrene-based elastomers are promising because they exhibit good rubber elasticity and excellent weather resistance and chemical resistance. Combining cellulose nanofibers with styrene-based elastomers can impart properties such as good tensile strength, tensile modulus, and tensile elongation at break in addition to the aforementioned inherent properties of styrene-based elastomers. However, styrene-based elastomers are inherently hydrophobic, while cellulose nanofibers are inherently hydrophilic due to the presence of hydroxyl groups, making them difficult to mix with each other. Poor mixing of styrene-based elastomers and cellulose nanofibers in a resin composition can result in molded articles from the resin composition not exhibiting the desired physical properties. Furthermore, when external force is applied to the molded article, voids may form between the styrene-based elastomer and cellulose nanofiber, causing the molded article to whiten. On the other hand, thorough melt-mixing of the styrene-based elastomer and cellulose nanofiber to achieve good mixing can result in thermal degradation of the cellulose nanofiber (e.g., discoloration). The techniques described in Patent Documents 1 and 2 involve dispersing cellulose in polyamide in the presence of a styrene-based elastomer, but do not focus on resin molded articles primarily composed of a styrene-based elastomer, and therefore do not address the above-mentioned problems associated with the combination of a styrene-based elastomer and cellulose nanofibers.

[0007] An object of one aspect of the present invention is to solve the above-mentioned problems and to provide a resin composition capable of forming a resin molded article that exhibits advantageous properties inherent to styrene-based elastomers (good rubber elasticity, weather resistance, chemical resistance, etc.) while also exhibiting excellent tensile strength, tensile modulus, and / or tensile elongation at break and that is less susceptible to disadvantages such as whitening and coloration, a method for producing the same, and a molded article obtained by molding the resin composition.

[0008] In addition, in order for a resin molded article containing a filler to exhibit desired properties, it is sometimes important that the filler be well dispersed in the resin. However, since cellulose is generally hydrophilic due to its hydroxyl groups, it has been proposed to use a styrene-based elastomer as an additive to disperse cellulose well in the polymer.

[0009] Because styrene-based elastomers are flexible and have excellent weather resistance, chemical resistance, and the like, molded articles using styrene-based elastomers as the main polymer component are also desired. However, conventionally, the applications of resin molded articles using styrene-based elastomers as the main polymer component have been limited. Styrene-based elastomers generally exhibit tackiness (initial adhesiveness). As a result, styrene-based elastomers have problems with processability and handleability, such as difficulty in melt molding using styrene-based elastomers alone and the tendency for styrene-based elastomer molded articles to stick to each other. The technology described in Patent Document 2 attempts to simultaneously achieve the contradictory 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 a styrene-based elastomer as the main polymer component.

[0010] Therefore, another aspect of the present invention aims to solve the above-mentioned problems and to provide a resin composition capable of forming a resin molded article that exhibits the excellent properties inherent to styrene-based elastomers (particularly, good rubber elasticity, weather resistance, chemical resistance, etc.) while also exhibiting excellent processability and handleability, a method for producing the same, and a resin molded article obtained by molding the resin composition.

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

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

[0013] According to another aspect of the present invention, a resin composition capable of forming a resin molded article that exhibits the excellent properties inherent to a styrene-based elastomer (particularly, good rubber elasticity, weather resistance, chemical resistance, etc.) while also exhibiting excellent processability and handleability, a method for producing the same, and a resin molded article obtained by molding the resin composition can be provided.

[0014] Illustrative embodiments of the present invention (hereinafter also referred to as the present embodiments) will be described below, but the present invention is not limited to these embodiments and various modifications are possible within the scope of the gist thereof.

[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 the 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, or in one aspect, a styrene-based elastomer and an acid-modified styrene-based elastomer. In one aspect, the number-average aspect ratio (L / D), which is the ratio 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. In one aspect, when the cellulose nanofibers are separated from the resin composition using tetrahydrofuran (THF), the weight gain of the cellulose nanofibers is 190% to 600%.

[0016] One aspect of the present invention provides a resin composition containing an acid-modified styrene-based elastomer, a styrene-based elastomer, and cellulose nanofibers. In the resin composition according to one aspect, the acid-modified styrene-based elastomer and the styrene-based elastomer are compatibilized and form a continuous phase without phase separation. In one aspect, the total amount of the acid-modified styrene-based elastomer and the styrene-based elastomer is 60% by mass or more, based on 100% by mass of the resin composition. The styrene-based elastomer moiety in the resin composition contributes to the expression of the good properties inherent to the styrene-based elastomer, while the acid-modified styrene-based elastomer moiety in the resin composition is interposed between the styrene-based elastomer and the cellulose nanofibers due to its good affinity with both the styrene-based elastomer and the cellulose nanofibers, thereby contributing to reducing problems caused by their poor affinity (e.g., void generation due to delamination between them).

[0017] It has been found that the presence of cellulose nanofibers and an acid-modified styrene-based elastomer in a resin composition according to one embodiment can reduce fuzzing during extrusion molding. This allows the molded article to exhibit good surface smoothness. While the reason why cellulose nanofibers and an acid-modified styrene-based elastomer are excellent at reducing fuzzing is unclear, it is possible that the cellulose nanofibers and the acid-modified styrene-based elastomer react to bond, modifying the surface of the styrene-based elastomer during molding, thereby exhibiting a smoothing effect. Furthermore, adding cellulose nanofibers to a styrene-based elastomer can 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. It has also been found that the presence of an acid-modified styrene-based elastomer in addition to cellulose nanofibers in a resin composition according to one embodiment can further improve the tensile strength, tensile modulus, tensile elongation at break, and / or hardness of the molded article, while reducing disadvantages such as whitening and discoloration of the molded article. Without being bound by theory, it is believed that the reaction between the hydroxyl groups of the 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 of the cellulose nanofibers to occur due to thermal degradation. This is thought to result in the cellulose nanofibers effectively improving physical properties, suppressing the generation of voids in the molded article due to delamination, reducing whitening, and further suppressing discoloration of the cellulose nanofibers. A resin composition according to one embodiment has excellent processability and handleability despite using a styrene-based elastomer that is excellent in rubber elasticity, weather resistance, chemical resistance, etc., and effectively improving physical properties due to the cellulose nanofibers. Furthermore, the resin composition is less susceptible to problems such as whitening and discoloration, making it suitable, for example, as a substitute for thermoplastic polyurethane elastomer (TPU).

[0018] Another aspect of the present invention provides a resin composition comprising a styrene-based elastomer and a tack inhibitor containing cellulose nanofibers. While styrene-based elastomers inherently possess excellent rubber elasticity, weather resistance, chemical resistance, and the like, their tackiness tends to make molding difficult and the molded articles difficult to handle. For example, tacky molding materials are difficult to separate from the mold during molding, and attempts to remove the molded articles from the mold with strong force result in deformation and breakage, making it difficult to obtain good molded articles. Furthermore, when tacky molded articles such as pellets, bales, injection-molded articles, films, sheets, and filaments are stored, contact points between the molded articles can block, making handling difficult in every process. It has been discovered that the presence of cellulose nanofibers in a resin composition reduces tackiness, facilitating molding and facilitating handling of the molded articles. The cellulose nanofibers in one aspect can function as a tack inhibitor, either alone or in combination with other components in the resin composition. While the reason why cellulose nanofibers have an excellent effect of reducing the tackiness of styrene-based elastomers is unclear, it is possible that the fine fibrous structure of cellulose nanofibers contributes to their greater physical entanglement with styrene-based elastomers than other fillers (e.g., silica particles, glass fiber, carbon fiber, etc.), resulting in a favorable tackiness reduction effect. Cellulose nanofibers are softer than, for example, silica particles, glass fiber, carbon fiber, etc., and therefore have the advantage of not impairing the inherent rubber elasticity of styrene-based elastomers. Furthermore, adding cellulose nanofibers to styrene-based elastomers can 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 exhibits reduced tackiness and excellent processability and handling properties despite the use of a styrene-based elastomer, making it useful as a soft resin molded article, and is also suitable as a substitute for, for example, thermoplastic polyurethane elastomer (TPU).

[0019] The resin composition according to one embodiment has a tack strength (hereinafter sometimes simply referred to as tack strength) of 10.0 gf / mm when measured by a probe tack test at 23°C, a load of 600 gf, a pressure time of 60 seconds, and a peeling speed of 600 mm / min. 2 In one embodiment, the tack strength is 9.0 gf / mm 2 or less than 7.0 gf / mm 2 or less, or 5.0 gf / mm 2 or less than 3.0 gf / mm 2 or less than 2.0 gf / mm 2 or less, or 1.5 gf / mm 2 or less than 1.0 gf / mm 2 In one embodiment, the tack strength may be 0.001 gf / mm or less from the viewpoint of ease of production of the resin composition. 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 It may be more than that.

[0020] The tack strength of a resin composition according to one embodiment 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, relative to 100% of the tack strength of a resin composition having the same composition but without the cellulose nanofibers. A smaller ratio is desirable from the viewpoint of suppressing tack, but in one embodiment, from the viewpoint of ease of production of 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 a resin composition according to one embodiment exhibits the above-exemplified ratio relative to 100% of the tack strength of the styrene-based elastomer contained in the resin composition.

[0021] Each component of the resin composition will be described below. In this embodiment, the amount of each component described as a value in the resin composition component may be regarded as the amount of each component in the resin composition, and the amount of each component described as a value in the resin composition may be regarded as the amount of each component in the resin composition component.

[0022] <Cellulose Nanofibers> Cellulose nanofibers are fibers obtained by pulverizing cellulose fiber raw materials through defibration treatment or the like. Natural cellulose and regenerated cellulose can be used as cellulose fiber raw materials. Examples of natural cellulose include wood pulp obtained from wood species (broadleaf or coniferous trees), 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). Examples of regenerated cellulose include regenerated cellulose fibers (viscose, cupro, Tencel, etc.), cellulose derivative fibers, and ultrafine threads of regenerated cellulose or cellulose derivatives obtained by electrospinning. Cellulose fiber raw materials that produce cellulose nanofibers with a fuzzed surface may be advantageous in terms of tack suppression. From this perspective, preferred cellulose fiber raw materials include cotton linters, etc.

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

[0024] The cellulose fiber raw material may be subjected to a pretreatment before defibration, which can adjust the fiber diameter, fiber length, degree of fibrillation, etc., the content of components other than cellulose (e.g., acid-insoluble components such as lignin, alkali-soluble polysaccharides such as hemicellulose, etc.), the 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 treatment using chemicals, such as digestion, bleaching, purification, hydrolysis, enzyme treatment, conversion to regenerated cellulose, and chemical modification. Grinding is a process in which a cellulose fiber raw material is pulverized in a dry manner. Grinding is a process in which a slurry obtained by dispersing a cellulose fiber raw material in a liquid medium is subjected to a grinding process, and is distinguished from the above-mentioned grinding in that it is a wet process. Classification is a separation operation for aligning the fiber length of the cellulose fiber raw material, and may be dry classification or wet classification.

[0026] The liquid medium may include water and / or other media (eg, organic solvents, inorganic acids, bases, and / or ionic liquids), and may include one or more media.

[0027] Examples of the organic solvent include one or more commonly used organic solvents, such as 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 (dimethylformamide, dimethylacetamide, acetonitrile, etc.); and sulfur-containing solvents (dimethyl sulfoxide). In a typical embodiment, the liquid medium in the slurry is substantially water alone.

[0028] In one aspect, the number average fiber length L of the cellulose nanofibers is preferably 100 nm or more, or 500 nm or more, or 1 μm or more, or 5 μm or more, or 10 μm or more, or 20 μm or more, from the viewpoint of satisfactorily exhibiting the property-improving effect of the cellulose nanofibers, and is 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 satisfactorily dispersing the cellulose nanofibers in the resin composition.

[0029] In one aspect, the number average fiber diameter D of the cellulose nanofibers is preferably 2 to 1,000 nm, from the viewpoint of obtaining a favorable effect of improving physical properties due to the cellulose nanofibers. The number average fiber diameter D of the cellulose nanofibers is more preferably 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] From the viewpoint of satisfactorily improving the mechanical properties of a rubber composite containing cellulose nanofibers with a small amount of cellulose nanofibers, the average fiber length (L) / fiber diameter (D) ratio of the 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. There is no particular upper limit, but from the viewpoint of handleability, it is preferably 5,000 or less, or 3,000 or less, or 2,000 or less, or 1,000 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) according to the following procedure. An aqueous dispersion of cellulose nanofibers is substituted with tert-butanol, diluted to 0.001 to 0.1% by mass, and dispersed using a high-shear homogenizer (e.g., IKA, product name "Ultra-Turrax T18") at 15,000 rpm for 3 minutes. The sample is then 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 with a magnification adjusted so that at least 100 cellulose nanofibers are observed, and the ratio (L / D) is calculated. The respective number average values ​​are taken as the number average fiber diameter L and number average fiber diameter D, and the ratio (L / D) is calculated.

[0032] In one embodiment, the number average aspect ratio, L / D, which is the ratio 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. The upper limit of this aspect ratio is not particularly limited, but from the viewpoint of handleability, it is preferably 25 or less. The lower limit of this 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, of which types I and II are particularly commonly used, while types III and IV are obtained on a laboratory scale but are not commonly used on an industrial scale. The cellulose nanofibers of the present disclosure are preferably cellulose nanofibers containing cellulose type I crystals or cellulose type II crystals, because they have relatively high structural mobility and, by dispersing the cellulose nanofibers in rubber, can produce molded articles with a lower linear expansion coefficient and superior strength and elongation during tensile and bending deformation. Cellulose nanofibers containing cellulose type I crystals and having a crystallinity of 55% or more 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 the cellulose nanofibers are dispersed in rubber, the strength and dimensional stability of the rubber composite tend to be high. A more preferred 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 the viewpoint of production, a preferred upper limit is 99%.

[0035] When the cellulose nanofiber is cellulose type I crystal (derived from natural cellulose), the crystallinity can be calculated by the Segal method from the diffraction pattern (2θ / deg. 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 due to the 200 plane (2θ = 22.5°) in cellulose type I crystal (amorphous) : The halo peak intensity due to amorphous in cellulose type I crystal, which is the peak intensity at an angle 4.5° lower than the diffraction angle of the 200 plane (2θ = 18.0°)

[0036] When the cellulose is cellulose type II crystal (derived from regenerated cellulose), the crystallinity can be calculated from the absolute peak intensity h0 at 2θ=12.6° assigned to the (110) plane peak of cellulose type II crystal in wide-angle X-ray diffraction and the peak intensity h1 of the baseline (the line connecting 2θ=8° and 2θ=15°) at this interplanar spacing, using the following formula: Crystallinity (%) = (h0-h1) / h0 × 100

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

[0038] From the viewpoint of processability and mechanical property expression, it is desirable that the degree of polymerization of the cellulose nanofibers be 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 expression, it is desirable that the degree of polymerization is not too low.

[0039] The degree of polymerization of cellulose nanofibers refers to the average degree of polymerization measured according to the reduced specific viscosity method using a copper ethylenediamine solution described in Verification Test (3) of the "15th Edition 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 (Mw / Mn) of the weight-average molecular weight to the number-average molecular weight (Mn) is 6 or less, preferably 5.6 or less, or 5.4 or less. A higher weight-average molecular weight indicates a lower number of terminal groups in the cellulose molecule. Furthermore, since the ratio (Mw / Mn) of the weight-average molecular weight to the number-average molecular weight represents the width of the molecular weight distribution, a lower Mw / Mn indicates a lower number of terminal groups in the cellulose molecule. Since the terminals of cellulose molecules serve as the starting point for thermal decomposition, particularly highly heat-resistant cellulose nanofibers and resin compositions containing cellulose nanofibers can be obtained when the cellulose molecules of the cellulose nanofibers not only have a high weight-average molecular weight but also a narrow molecular weight distribution. From the perspective of easy availability of cellulose raw materials, the weight-average molecular weight (Mw) of the cellulose nanofiber may be, for example, 600,000 or less, 500,000 or less, or 400,000 or less. From the viewpoint of the ease of availability of cellulose fiber raw materials, the number average molecular weight (Mn) of cellulose nanofibers may be, for example, 200,000 or less, or 150,000 or less, or 100,000 or less, or 80,000 or less, or 60,000 or less. From the viewpoint of the ease of production of cellulose nanofibers, the ratio of weight average molecular weight to number average molecular weight (Mn) (Mw / Mn) may be, for example, 1.5 or more, or 1.7 or more, or 2 or more. Mw can be controlled within the above range by selecting a cellulose raw material having an Mw appropriate for the purpose, or by appropriately performing physical and / or chemical treatments on the cellulose raw material within an appropriate range, etc. Mw / Mn can also be controlled within the above range by selecting a cellulose raw material having an Mw / Mn appropriate for the purpose, or by appropriately performing physical and / or chemical treatments on the cellulose raw material within an appropriate range, etc. In one embodiment, the Mw and Mw / Mn of the cellulose raw material may each be within the above range.

[0041] The weight average molecular weight and number average molecular weight of the cellulose nanofibers referred to here are values ​​determined by dissolving the cellulose nanofibers in N,N-dimethylacetamide containing added lithium chloride and then performing gel permeation chromatography using N,N-dimethylacetamide as a solvent.

[0042] Alkali-soluble polysaccharides that cellulose nanofibers may contain include hemicellulose, as well as β-cellulose and γ-cellulose. Alkali-soluble polysaccharides are understood by those skilled in the art as components obtained as the alkali-soluble portion of holocellulose obtained by solvent extraction and chlorine treatment of plants (e.g., wood) (i.e., components obtained by removing α-cellulose from holocellulose). Alkali-soluble polysaccharides are polysaccharides containing hydroxyl groups and have poor heat resistance, which can lead to disadvantages such as decomposition when heated, yellowing during thermal aging, and a decrease in the strength of cellulose nanofibers. Therefore, it is preferable that the content of alkali-soluble polysaccharides in cellulose nanofibers is low.

[0043] In one aspect, the average content of alkali-soluble polysaccharides in the 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, relative to 100% by mass of the cellulose nanofibers, from the viewpoint of obtaining good dispersibility of the cellulose nanofibers. From the viewpoint of ease of production of the cellulose nanofibers, the content may be 1% by mass or more, 2% by mass or more, or 3% by mass or more.

[0044] The average alkali-soluble polysaccharide content can be determined by the method described in a non-patent document (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 the art 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 contents is taken as the average alkali-soluble polysaccharide content.

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

[0046] The average acid-insoluble component content is determined by quantifying the acid-insoluble component using the Clason method described in the non-patent document (Wood Science Experiment Manual, edited by the Japan Wood Research Society, pp. 92-97, 2000). This method is recognized in the industry as a method for measuring lignin content. The sample is stirred in a sulfuric acid solution to dissolve cellulose, hemicellulose, etc., and then filtered through a glass fiber filter. The resulting residue corresponds to the acid-insoluble component. The acid-insoluble component content is calculated from the weight of this acid-insoluble component. The acid-insoluble component content is then measured three times for each sample, and the number average is taken as the average acid-insoluble component content.

[0047] [Chemical Modification] The cellulose nanofibers may be chemically modified cellulose nanofibers (also referred to as 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 acetylation and propionylation; ethers such as methyl ether, hydroxyethyl ether, hydroxypropyl ether, hydroxybutyl ether, carboxymethyl ether, and cyanoethyl ether; and TEMPO oxides obtained by oxidizing the primary hydroxyl groups of cellulose. The 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, with acetylation being particularly preferred. Preferred esterifying agents are acid halides, acid anhydrides, vinyl carboxylate esters, and carboxylic acids. Among these esterification reaction agents, at least one selected from the group consisting of acetic anhydride, propionic anhydride, butyric anhydride, vinyl acetate, vinyl propionate, vinyl butyrate, and acetic acid is particularly preferred from the standpoint of reaction efficiency. Acetic anhydride and vinyl acetate are particularly preferred. The cellulose nanofibers may be chemically modified with a modifying agent, for example, at the stage of raw cellulose fiber, during the defibration treatment, or after the defibration treatment, or may be chemically modified during or after the preparation of a slurry as a dispersion, or during or after the drying process.

[0048] [Degree of acyl substitution (DS)] When cellulose nanofibers are chemically modified (for example, by hydrophobization such as acylation), the cellulose nanofibers tend to have good dispersibility 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 more, or 0.2 or more, or 0.25 or more, or 0.3 or more, or 0.5 or more, in order to obtain esterified cellulose nanofibers with a high thermal decomposition onset temperature. Since an unmodified cellulose skeleton remains in the esterified cellulose nanofibers, it is possible to obtain esterified cellulose nanofibers that combine the high tensile strength and dimensional stability inherent to cellulose with the high thermal decomposition onset temperature inherent to chemical modification. DS is preferably 2.0 or less, or 1.8 or less, or 1.5 or less, or 1.2 or less, or 1.0 or less, or 0.8 or less, or 0.7 or less, or 0.6 or less, or 0.5 or less.

[0049] When the modifying group of the chemically modified cellulose nanofiber is an acyl group, the degree of acyl substitution (DS) can be calculated from the reflection infrared absorption spectrum of the esterified cellulose nanofiber 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 absorption band of C=O based on the acyl group is at 1730 cm -1 The peak of the absorption band of C—O based on the cellulose backbone appears at 1030 cm -1 The DS of the esterified cellulose nanofiber can be determined by creating a correlation graph between the DS obtained from the solid-state NMR measurement of the esterified cellulose nanofiber described below and the modification degree (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 C-O in the cellulose backbone chain, and using the calibration curve calculated from the correlation graph: Degree of substitution DS = 4.13 × IR index (1030). IR index (1030) = H1730 / H1030 In the formula, H1730 and H1030 are 1730 cm -1, 1030 cm -1 (absorption band of C-O stretching vibration of cellulose backbone chain). -1 and 1500 cm -1 The line connecting the -1 and 1500 cm -1 The line connecting these is taken as the baseline, and the absorbance is calculated when this baseline is taken as 0.

[0050] The method for calculating the DS of esterified cellulose nanofibers by solid-state NMR is as follows: 13 C solid-state NMR measurement is performed, and DS can be calculated using the following formula, which is the ratio of the total area intensity (Inp) of signals assigned to carbon atoms C1-C6 derived from the pyranose ring of cellulose appearing in the range of 50 ppm to 110 ppm to the area intensity (Inf) of a signal assigned to one carbon atom derived from the modifying group: DS = (Inf) x 6 / (Inp). For example, if the modifying group is an acetyl group, the signal at 23 ppm assigned to -CH3 can be used. 13 The conditions for C solid-state NMR measurement are, for example, as follows: Apparatus: Bruker Biospin Avance 500WB Frequency: 125.77 MHz Measurement method: DD / MAS method Waiting time: 75 sec NMR sample tube: 4 mmφ Number of accumulations: 640 (approximately 14 hours) MAS: 14,500 Hz Chemical shift reference: glycine (external reference: 176.03 ppm)

[0051] The thermal decomposition temperature of cellulose nanofiber (T D From the viewpoint of being able to exhibit the heat resistance and mechanical strength desired for in-vehicle applications and the like, in one aspect, the thermal decomposition onset 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. The higher the thermal decomposition onset temperature, the more preferable, but from the viewpoint of ease of production of 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℃ ) )] The temperature at which the cellulose nanofiber loses 1 wt% of its weight (T 1% In one aspect, from the viewpoint of avoiding thermal degradation during melt-kneading and being able to exhibit mechanical strength, 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. 1% The higher the temperature, the better, but from the viewpoint of ease of production of cellulose nanofibers, it may be, for example, 330°C or less, 320°C or less, or 310°C or less.

[0053] Weight loss rate of cellulose nanofiber at 250°C (T 250℃ From the viewpoint of avoiding thermal degradation during melt-kneading and being able to exhibit mechanical strength, in one aspect, T 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℃ The lower the better, but from the viewpoint of ease of production of 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 is a value obtained from a graph in thermogravimetry (TG) analysis, where the horizontal axis is temperature and the vertical axis is weight residual rate %. Starting from the weight of cellulose nanofiber at 150°C (a state in which moisture is almost completely removed) (weight loss of 0 wt%), the temperature is further increased, and the temperature at which the weight loss reaches 1 wt% (T 1% ) and the temperature at 2 wt% weight loss (T 2% The temperature at the point where this line intersects with the horizontal line (baseline) that passes through the starting point of the weight loss of 0 wt% is called T D It is defined as:

[0055] 1% weight loss temperature (T 1% ) is the above T D The temperature is the temperature at which the weight loss reaches 1% by weight, starting from the weight at 150°C, when the temperature is continued to be increased by the method of (1).

[0056] Weight loss rate of cellulose nanofiber at 250°C (T 250℃ ) is the weight loss rate when cellulose nanofibers are held at 250°C under nitrogen flow for 2 hours in TG analysis. A porous sheet of cellulose nanofibers is heated from room temperature to 150°C at a temperature increase 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 temperature increase rate of 10°C / min, and held at 250°C for 2 hours. Starting with the weight W0 at the time when 250°C is reached, the weight after holding at 250°C for 2 hours is defined as W1, and is calculated using the following formula: Weight change rate at 250°C (%): (W1 - W0) / W0 x 100

[0057] [Porous Sheet] Various physical properties of cellulose nanofiber (crystallinity, crystalline polymorphism, degree of polymerization, Mw, Mn, Mw / Mn, alkali-soluble content, average acid-insoluble content, T D , T 1% , T 250℃ Measurements of materials such as cellulose, cellulose acetate, and cellulose nitrate may vary significantly depending on the shape of the sample. To ensure stable and reproducible measurements, a porous sheet without distortion is used as the measurement sample. The porous sheet is prepared 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 further dispersion treatment is performed using a mixer or the like until no aggregates are present. The concentration is adjusted to 0.5% by mass per 0.5 g of cellulose nanofiber solids. 100 g of the resulting tert-butanol dispersion is filtered on filter paper. Without peeling the filtered material from the filter paper, it is sandwiched together with the filter paper between two larger pieces of filter paper, and dried in an oven at 150°C for 5 minutes while pressing down the edges of the larger filter paper with weights. The filter paper is then peeled off to obtain a porous sheet with little distortion. The air resistance R of this sheet is 10 g / m2. 2 A porous sheet having a flow rate of 100 sec / 100 ml or less is used as a measurement sample.

[0059] The air resistance R was measured by measuring the basis weight W (g / m) of a porous sheet sample left standing for one day in an environment of 23°C and 50% RH.2 ) is measured, and then the air resistance R (sec / 100 ml) is measured using an Oken type air resistance tester (for example, manufactured by Asahi Seiko Co., Ltd., Model EG01). At this time, 10 g / m 2 Calculate the value per unit area. Unit area 10 g / m 2 Air resistance per unit area (sec / 100 ml) = R / W x 10

[0060] [Specific Surface Area] The specific surface area of ​​the cellulose nanofiber is preferably 10 m² or less, because the cellulose nanofiber is highly fined, resulting in a good color tone of the resin composition, and the tackiness of the styrene-based elastomer is excellent. 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 / g 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 measured by using a specific surface area and pore size distribution measuring device (e.g., Nova-4200e, manufactured by Quantachrome Instruments) to measure the amount of nitrogen gas adsorption at the boiling point of liquid nitrogen at five points in the range of relative vapor pressure (P / P0) of 0.05 to 0.2 (multipoint method), and then calculating the BET specific surface area (m 2 / g).

[0061] Alternatively, the specific surface area of ​​the cellulose nanofibers is preferably 10 m or less, since the transparency of the resin composition is good due to the highly fine cellulose nanofibers. 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 / g 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 / g or less. The above range is particularly suitable in an embodiment in which 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, the preferred specific surface area is 10 m 2 / g or more, or 20m 2 / g or more, or 30m 2 / 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, crystallinity, crystalline polymorphism, degree of polymerization, Mw, Mn, Mw / Mn, alkali-soluble content, average acid-insoluble content, T D , T 1% , T 250℃ The properties of the cellulose nanofibers (e.g., DS, specific surface area) are analyzed using the following method. The polymer components contained in the resin composition are dissolved in an organic or inorganic solvent that can dissolve the polymer components, and the cellulose nanofibers are separated and thoroughly washed with the solvent, after which the solvent is replaced with tert-butanol. The cellulose nanofiber tert-butanol slurry is then analyzed using the same measurement method as above, and the various physical properties of the cellulose nanofibers in the resin composition are calculated.

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

[0064] In one embodiment, the cellulose nanofibers may be provided in the form of a slurry containing a liquid medium, or in the form of a dried product such as particles, a film, or a bulk. Examples of the liquid medium include water and / or an organic solvent having a boiling point, and the cellulose nanofibers may contain one or more types of medium. The liquid medium content in the slurry form is 50% by mass or more, and the liquid medium content in the dried product is less than 50% by mass. The liquid medium content is the value measured when heated at 180°C using an infrared heating moisture meter (e.g., trade name "MX-50" manufactured by A&D Corporation). In an embodiment 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-based elastomer be in the form of a dry product.

[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 the cellulose nanofibers well, and is 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 an embodiment using a tack inhibitor containing cellulose nanofibers, a particularly preferred amount of cellulose nanofibers from the viewpoint of exhibiting a good tack suppression 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, an acid-modified styrene-based elastomer, a styrene-based elastomer and an acid-modified styrene-based elastomer, and a styrene-based elastomer and an acid-modified styrene-based elastomer. In the present disclosure, an elastomer, in one embodiment, refers to a substance (specifically, a natural or synthetic polymer substance) that is elastic at room temperature (23°C). Furthermore, being elastic, in one embodiment, means that the storage modulus at 23°C and 10 Hz measured by dynamic viscoelasticity measurement is 1 MPa or more and 100 MPa or less. Examples of elastomers that the thermoplastic elastomer may include other than the styrene-based elastomer and the acid-modified styrene-based elastomer 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-based elastomers, polyurethane-based elastomers, polyamide-based 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 flexibility, and is 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 containing desired amounts of other components. In one aspect, the total ratio of the styrene-based elastomer and the acid-modified elastomer to 100% by mass of the thermoplastic elastomer may be 1% by mass or more, or 5% by mass or more, or 10% by mass or more, or 20% by mass or more, or 50% by mass or more, or 70% by mass or more, and in one aspect, 100% by mass.

[0067] <Styrene-based elastomer and acid-modified styrene-based elastomer> A resin composition according to one embodiment includes a styrene-based elastomer. A resin composition according to one embodiment includes a styrene-based elastomer and an acid-modified styrene-based elastomer. In one embodiment, the styrene-based elastomer is a copolymer of a conjugated diene monomer and an aromatic vinyl monomer. Examples of the conjugated diene monomer 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, and these may be used alone or in combination of two or more. The aromatic vinyl monomer is not particularly limited as long as it is a monomer copolymerizable with the conjugated diene monomer, and examples thereof include styrene, m- or p-methylstyrene, α-methylstyrene, ethylstyrene, p-tert-butylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, diphenylethylene, and divinylbenzene, which may be used alone or in combination of two or more. From the viewpoints of the moldability of the resin composition and the 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. The composition distribution of each monomer in the copolymer chain includes a completely random copolymer with a statistically random composition, and a tapered (gradient) random copolymer with a gradient in composition 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] The block copolymer may be a copolymer consisting of two or more blocks. For example, the block copolymer may have a structure such as A-B, A-B-A, or A-B-A-B, in which a block A of an aromatic vinyl monomer and a block B of a conjugated diene monomer and / or a copolymer of an aromatic vinyl monomer and a conjugated diene monomer constitute a block copolymer. The boundaries between the blocks do not necessarily need to be clearly distinguished. For example, when block B is a copolymer of an aromatic vinyl monomer and a conjugated diene monomer, the aromatic vinyl monomer in block B may be distributed uniformly or in a tapered manner. Furthermore, block B may have a plurality of portions where the aromatic vinyl monomer is distributed uniformly and / or a plurality of portions where the aromatic vinyl monomer is distributed in a tapered manner. Furthermore, block B may have a plurality of segments with different aromatic vinyl monomer contents. When a copolymer contains a plurality of blocks A and a plurality of blocks B, the molecular weights and compositions of the blocks A and B 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 product thereof. The block copolymer may be a mixture of two or more types that differ from each other in one or more of the bond type, molecular weight, type of aromatic vinyl compound, type of conjugated diene compound, 1,2-vinyl content or the total amount of 1,2-vinyl content and 3,4-vinyl content, content of aromatic vinyl compound component, hydrogenation rate, etc.

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

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

[0073] The acid-modified styrene-based elastomer may be an acid-modified product of the styrene-based elastomer exemplified above. In this disclosure, the acid-modified styrene-based elastomer means that an acidic functional group is attached to the molecular skeleton of the styrene-based elastomer via a chemical bond as an acid-modifying group. In this disclosure, the acidic functional group means a functional group capable of reacting with a basic functional group, etc., and specific examples include a hydroxyl group, a carboxyl group, a carboxylate group, a sulfo group, and an acid anhydride group.

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

[0075] In a preferred embodiment, the acid-modified styrene-based elastomer is an acid-modified styrene-based elastomer, which is an aromatic vinyl compound-conjugated diene compound copolymer (preferably, an aromatic vinyl compound-conjugated diene compound block copolymer) or a hydrogenated product thereof. Examples of such acid-modified styrene-based elastomers include elastomers obtained by grafting an α,β-unsaturated dicarboxylic acid or a derivative thereof onto an aromatic compound-conjugated diene copolymer (preferably, a block copolymer) or a hydrogenated product thereof, in the presence or absence of a peroxide. Specific examples of α,β-unsaturated dicarboxylic acids and derivatives thereof include maleic acid, fumaric acid, maleic anhydride, and fumaric anhydride, with maleic anhydride being particularly preferred. In a preferred embodiment, the acid-modified styrene-based elastomer is an acid anhydride-modified styrene-based elastomer.

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

[0077] The styrene unit ratio of the acid-modified styrene-based elastomer and the unit ratio of the styrene-based elastomer are preferably 10% by mass or more, or 19% by mass or more, or 29% by mass or more, from the viewpoint of affinity between the acid-modified styrene-based elastomer and the styrene-based elastomer and from the viewpoint of well exhibiting the advantageous properties inherent to the styrene-based elastomer, and are preferably 45% by mass or less, or 40% by mass or less, or 35% by mass or less, from the viewpoint of hardness. The styrene unit ratio is a value determined by the following method. Specifically, a predetermined amount of elastomer is dissolved in chloroform and measured with an ultraviolet spectrophotometer (e.g., UV-2450, manufactured by Shimadzu Corporation), and the content of aromatic vinyl monomer units (styrene) is calculated using a calibration curve from the peak intensity at the absorption wavelength (262 nm) attributable to 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, or 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 well exhibiting the advantageous properties inherent to the styrene elastomer, and are preferably 40 mol% or less, or 35 mol% or less, or 30 mol% or less, or 25 mol% or less, from the viewpoint of flexibility of the composition. These unit ratios are suitable in embodiments using a tack inhibitor containing cellulose nanofibers. The styrene unit ratio is a value determined by NMR.

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

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

[0081] With regard to the styrene-based elastomer and the acid-modified styrene-based elastomer, the amount of vinyl bonds (for example, 1,2- or 3,4-bonds of butadiene) in the conjugated diene bond units in the conjugated diene-based polymer 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 (for example, 1,2-bonds of butadiene) in the conjugated diene bond units is 13It can be determined by the C-NMR method (quantitative mode). 13 By integrating the areas of the following peaks that appear in C-NMR, a value proportional to the carbon content of each structural unit can be obtained, which can then be converted into the mass % 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 the aromatic vinyl monomer bonded to the conjugated diene monomer (also referred to as the aromatic vinyl bond amount in the present disclosure) may be preferably 5.0% by mass or more and 70% by mass or less, 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-based elastomer is preferably 10,000 or more, or 30,000 or more, or 50,000 or more from the viewpoint of affinity with the styrene-based elastomer, and is preferably 500,000 or less, or 250,000 or less, or 200,000 or less from the viewpoint of affinity with the cellulose nanofiber.

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

[0085] In one embodiment, the total amount of the acid-modified styrene-based elastomer and the styrene-based 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. In one embodiment, the total amount is 90% by mass or less, or 85% by mass or less, or 80% by mass or less, from the viewpoint of containing desired amounts of other components, particularly cellulose nanofibers.

[0086] The amount of the acid-modified styrene-based elastomer relative to 100 parts by mass of the styrene-based 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 viewpoints of improving the surface smoothness of the molded article, whitening resistance when the molded article is stretched (suppression of void generation), etc., and is 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 reduction in hardness caused by a large amount of the acid-modified styrene-based elastomer.

[0087] The amount of acid-modified styrene-based elastomer per 1 part by mass of cellulose nanofibers 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 viewpoints of improving the surface smoothness of the molded article and the resistance to whitening when the molded article is stretched (suppressing the occurrence of voids), and from the viewpoints of suppressing discoloration, shrinkage during molding, and / or a decrease in hardness caused by a large amount of acid-modified styrene-based elastomer, the amount is 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. In a resin composition according to one embodiment, the number of acid-modified groups in the acid-modified styrene-based elastomer is not excessive compared to the number of hydroxyl groups in the surface portion of the cellulose nanofibers (specifically, the portion that gives the surface area in the specific surface area measurement of the cellulose nanofibers). The number of hydroxyl groups in the surface portion of the cellulose nanofibers in the resin composition can be calculated from the amount of cellulose nanofibers in the resin composition, the fiber diameter, and the specific surface area. For example, when an acid-modified product is used for the purpose of chemically modifying cellulose nanofibers, an excess amount of the acid-modified product may be added relative to the cellulose nanofibers, but in this embodiment, it may be advantageous to minimize the amount of acid-modified styrene-based elastomer present in the resin composition to the extent that the desired affinity with the cellulose nanofibers is obtained. From this perspective, it is preferable to adjust the amount of acid-modified styrene-based elastomer so that it is not excessive relative to the number of hydroxyl groups in the cellulose nanofibers, and the upper limit exemplified above is suitable from this perspective.

[0088] The amount of acid-modified groups in the acid-modified styrene-based 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-based elastomer, from the viewpoint of affinity with cellulose nanofibers, and is 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 reduction in hardness due to the acid-modified styrene-based elastomer.

[0089] The amount of the acid-modified styrene-based 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 viewpoints of improving the surface smoothness of the molded article, whitening resistance of the molded article when stretched (suppression of void generation), etc., and is preferably 50% by mass or less, or 40% by mass or less, or 30% by mass or less from the viewpoint of suppressing discoloration, shrinkage during molding, and / or reduction in hardness caused by a large amount of the acid-modified styrene-based elastomer. Note that acid-modified styrene-based elastomers are generally relatively expensive, and therefore reducing the amount used is advantageous in terms of cost.

[0090] In one aspect, the behavior of the stress-strain curve (e.g., yield behavior) in a tensile test of the resin composition may be controlled depending on the desired application of the resin composition by selecting the type and / or amount of the acid-modified styrene-based 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 to styrene-based elastomers, and is 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 the 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 30% by mass or more, from the viewpoint of well exhibiting the advantageous properties inherent to the styrene-based elastomer, and is preferably 98.8% by mass or less, or 90% by mass or less, or 80% by mass or less, from the viewpoint of containing desired amounts of other components.

[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 is 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] <Styrenic elastomer and acid-modified styrene-based elastomer in an embodiment using a tack inhibitor containing cellulose nanofibers> Examples of styrene-based elastomers and acid-modified styrene-based elastomers that are particularly suitable for an embodiment using a tack inhibitor containing cellulose nanofibers are described below. 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 body, while reducing problems such as whitening and discoloration of the molded body. Without being bound by theory, it is believed that the reaction between the hydroxyl groups of the cellulose nanofibers and the acid-modified groups of the acid-modified styrene-based elastomer strengthens the interface between them, making it less likely for peeling to occur between the styrene-based elastomer, cellulose nanofibers, and acid-modified styrene-based elastomer when an 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. This is thought to allow the cellulose nanofibers to exhibit a favorable effect of improving physical properties, suppress the generation of voids in the molded body due to peeling, reduce whitening, and further suppress discoloration of the cellulose nanofibers. The presence of an acid-modified styrene-based elastomer in the resin composition is also advantageous in terms of further reducing tackiness caused by the styrene-based elastomer.

[0095] In a resin composition according to one embodiment, the acid-modified styrene-based elastomer and the styrene-based elastomer are compatibilized without phase separation, forming a continuous phase. In a resin composition according to one embodiment, the acid-modified styrene-based elastomer forms a first phase, and the styrene-based elastomer forms a second phase that is phase-separated from the first phase. In one embodiment, the total amount of the acid-modified styrene-based elastomer and the styrene-based elastomer is 60% by mass or more in 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 a domain size of, for example, 20 nm to 10 μm. The domain size can be determined from a scanning electron microscope (SEM) image. Alternatively, in one embodiment, each of the first phase and the second phase may be a continuous phase. Due to the phase separation between the acid-modified styrene-based elastomer and the styrene-based elastomer, the styrene-based elastomer portion in the resin composition contributes to the expression of the good properties that the styrene-based elastomer originally possesses, while the acid-modified styrene-based elastomer portion in the resin composition is interposed between the styrene-based elastomer and the cellulose nanofiber due to its good affinity with both the styrene-based elastomer and the cellulose nanofiber, thereby contributing to further enhancing the property-improving effect of the cellulose nanofiber.

[0096] The acid-modified styrene-based elastomer may be an acid-modified product of the styrene-based elastomer exemplified above. Suitable examples of the acid-modified styrene-based elastomer 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 that styrene-based elastomers inherently possess, and is 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 body.

[0098] The amount of the 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 inherent advantages of the styrene-based elastomer well, and is 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 containing 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 is 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 is 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 the styrene-based elastomer.

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

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

[0103] The melt mass flow rate (MFR) of the acid-modified styrene-based 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-based elastomer, and 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 affinity with the cellulose nanofiber.

[0104] In one embodiment, the total amount of the acid-modified styrene-based elastomer and the styrene-based 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. In one embodiment, from the viewpoint of containing a desired amount of other components, particularly cellulose nanofibers, the 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.

[0105] The amount of the acid-modified styrene-based elastomer relative to 100 parts by mass of the styrene-based 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-based elastomer well, and is 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 reduction in hardness caused by a large amount of the acid-modified styrene-based elastomer.

[0106] The amount of acid-modified styrene-based 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-based elastomer well, and is preferably 45 parts by mass or less, or 30 parts 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 reduction in hardness caused by a large amount of acid-modified styrene-based elastomer.

[0107] The amount of the 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 the acid-modified styrene elastomer well, and is 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 reduction in hardness caused by a large amount of acid-modified styrene elastomer. Note that acid-modified styrene elastomers are generally relatively expensive, and therefore reducing the amount used is advantageous in terms of cost.

[0108] The content of the 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] In the resin composition components, the total content of the styrene-based elastomer and the acid-modified styrene-based elastomer 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 the acid-modified styrene-based elastomer relative to 100 parts by mass of the total of the styrene-based elastomer and the acid-modified styrene-based 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 components 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, per 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. The liquid polymer refers to a polymer that has fluidity 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-based polymer or a non-conjugated diene-based polymer. In one embodiment, the liquid polymer is liquid rubber. In the present disclosure, liquid rubber refers to a substance that has fluidity at 23°C and forms a rubbery elastomer by crosslinking (more specifically, vulcanization) and / or chain extension. In other words, in one embodiment, the liquid rubber is an uncured product.

[0114] In one embodiment, having fluidity means that when a liquid polymer dissolved in cyclohexane is placed in a vial having a body diameter of 21 mm and a total length of 50 mm at 23°C and then dried, the liquid polymer is filled into the vial to a height of 1 mm, the vial is sealed, and the vial is left standing upside down for 24 hours, and a movement of the material in the vertical direction of 0.1 mm or more can be confirmed.

[0115] The liquid polymer may have a monomer composition of a typical polymer, and preferably has a relatively low molecular weight from the viewpoints of ease of handling and good dispersibility of cellulose nanofibers. In one aspect, the liquid polymer is in a 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 the present disclosure are values ​​determined in terms of standard polystyrene using gel permeation chromatography, using chloroform as a solvent, and at a measurement temperature of 40°C.

[0116] In one embodiment, a liquid polymer may be combined with cellulose nanofibers to form a masterbatch, and such 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 viewpoints of thermal stability and the effect of improving the dispersibility of cellulose nanofibers in the resin, and 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, or 2,000 or more, or 4,000 or more from the viewpoints of thermal stability and the effect of improving the dispersibility of cellulose nanofibers in the resin, and is preferably 240,000 or less, or 150,000 or less, or 30,000 or less from the viewpoint 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 more, or 1.8 or more, or 2 or more, in that a certain degree of variation in molecular weight makes it possible to achieve a high level of compatibility between multiple properties (in one embodiment, a high level of compatibility between good dispersion of cellulose nanofibers in the resin and good flexural modulus of the resin composition), and is preferably 10 or less, or 8 or less, or 5 or less, or 3 or less, or 2.7 or less, in that the variation in molecular weight is not excessively large and the desired physical properties of the resin composition can be stably obtained, for example, in that a balance between fluidity and impact resistance can be achieved.

[0120] The liquid polymer may have good thermal stability. The thermal decomposition temperature (T D In terms of good thermal stability, in one embodiment, the thermal decomposition onset temperature is higher than 200° C., or 210° C. or higher, or 230° C. or higher, or 250° C. or higher, or 300° C. or higher. Although a higher thermal decomposition onset temperature is preferred, in terms of easy availability of the liquid polymer, in one embodiment, the thermal decomposition onset temperature may be 500° C. or lower, or 450° C. or lower, or 400° C. or lower.

[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 is 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 includes a diene polymer, and in another embodiment, the liquid polymer includes a conjugated diene polymer, a non-conjugated diene polymer, or a hydrogenated product thereof. The above polymer or its hydrogenated product may be an oligomer. The monomer 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 (e.g., one or more selected from the group consisting of hydroxyl groups, carboxy groups, isocyanato groups, thio groups, amino groups, and halo groups) at both ends, and thus may be bifunctional. These reactive groups contribute to crosslinking and / or chain extension of the liquid polymer.

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

[0124] Examples of the conjugated diene monomer 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, and these may be used alone 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 the conjugated diene monomer, and examples thereof include styrene, m- or p-methylstyrene, α-methylstyrene, ethylstyrene, p-tert-butylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, diphenylethylene, and divinylbenzene, and these may be used alone or in combination of two or more. From the viewpoints of the moldability of the resin composition and the 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. The composition distribution of each monomer in the copolymer chain includes a completely random copolymer that is close to a statistically random composition, and a tapered (gradient) random copolymer with a gradient in composition 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] The block copolymer may be a copolymer consisting of two or more blocks. For example, the block copolymer may have a structure such as A-B, A-B-A, or A-B-A-B, in which a block A of an aromatic vinyl monomer and a block B of a conjugated diene monomer and / or a copolymer of an aromatic vinyl monomer and a conjugated diene monomer constitute a block copolymer. The boundaries between the blocks do not necessarily need to be clearly distinguished. For example, when block B is a copolymer of an aromatic vinyl monomer and a conjugated diene monomer, the aromatic vinyl monomer in block B may be distributed uniformly or in a tapered manner. Furthermore, block B may have a plurality of portions where the aromatic vinyl monomer is distributed uniformly and / or a plurality of portions where the aromatic vinyl monomer is distributed in a tapered manner. Furthermore, block B may have a plurality of segments with different aromatic vinyl monomer contents. When a copolymer contains a plurality of blocks A and a plurality of blocks B, the molecular weights and compositions of the blocks A and B may be the same or different.

[0128] The block copolymer may be a mixture of two or more types that differ from each other in one or more of the bonding type, molecular weight, aromatic vinyl compound type, conjugated diene compound type, 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] The amount of vinyl bonds in the conjugated diene bond units in the conjugated diene polymer (for example, 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. 13 It can be determined by the C-NMR method (quantitative mode). 13 By integrating the areas of the following peaks that appear in C-NMR, a value proportional to the carbon content of each structural unit can be obtained, which can then be converted into the mass % of each structural unit: Styrene 145-147 ppm Vinyl 110-116 ppm Diene (cis) 24-28 ppm Diene (trans) 29-33 ppm

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

[0131] Examples of the hydrogenated conjugated diene polymer include the hydrogenated conjugated diene polymers exemplified above, and may be, for example, hydrogenated products of butadiene homopolymer, isoprene homopolymer, styrene-butadiene copolymer, and acrylonitrile-butadiene copolymer.

[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, which may be derivatives thereof (e.g., maleic anhydride-modified products, methacrylic acid-modified products, terminal hydroxyl group-modified products, hydrogenated products, and combinations thereof).

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

[0134] In the ethylene-α-olefin copolymer, examples of monomers that can be copolymerized with ethylene units include aliphatic substituted vinyl monomers such as 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, and isobutylene, and styrene. aromatic vinyl monomers such as vinyl acetate, acrylic acid esters, methacrylic acid esters, glycidyl acrylic acid esters, glycidyl methacrylic acid esters, and 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 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 a number average molecular weight (Mn) measured using a gel permeation chromatography measuring device with 1,2,4-trichlorobenzene as a solvent at 140°C and polystyrene standards.

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

[0138] Ethylene-α-olefin copolymers can be produced by conventionally known production methods such as those described in, for example, JP-B-4-12283, JP-A-60-35006, JP-A-60-35007, JP-A-60-35008, JP-A-5-155930, JP-A-3-163088, and U.S. Pat. No. 5,272,236.

[0139] In one embodiment, the liquid polymer comprises at least one selected from the group consisting of diene rubber, silicone rubber, urethane rubber, polysulfide rubber, and hydrogenated products 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 the cellulose nanofibers in the liquid polymer, and is preferably 100 mPa·s or more, or 300 mPa·s or more, or 500 mPa·s or more, from the viewpoints of thermal stability, the effect of improving the dispersibility of the cellulose nanofibers in the resin, and the 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 dispersing the cellulose nanofibers well in the liquid polymer and dispersing the cellulose nanofibers well in the resin by heat kneading, and is preferably 50 mPa·s or more, or 100 mPa·s or more, or 500 mPa·s or more, from the viewpoints of thermal stability, the effect of improving the dispersibility of the cellulose nanofibers in the resin, and the 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 dispersing the cellulose nanofibers well in the liquid polymer and dispersing the cellulose nanofibers well in the resin by heat kneading, and is preferably 50 mPa·s or more, or 100 mPa·s or more, or 300 mPa·s or more, from the viewpoints of thermal stability, the effect of improving the dispersibility of the cellulose nanofibers in the resin, and the 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 is 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, the effect of improving the dispersibility of cellulose nanofibers in the resin, and the mechanical properties of the resin composition.

[0144] It is preferable that the viscosities of the liquid polymer at 80°C, 50°C, 25°C and 0°C are all within the above ranges, as this allows the cellulose nanofibers to be well dispersed in the liquid polymer over a wide range of mixing temperatures.

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

[0146] In the resin composition, the amount of the liquid polymer relative to 100 parts by mass of the 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 is 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 the acid-modified styrene-based elastomer well or from the viewpoint of obtaining a resin composition exhibiting the inherent physical properties of the styrene-based elastomer.

[0147] In the resin composition, the amount of liquid polymer per 100 parts by mass of cellulose nanofibers 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 the advantages of the liquid polymer well, and is 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 product.

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

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

[0150] [Amphiphilic Molecules] In amphiphilic molecules, the hydrophilic segment is a portion that exhibits good affinity with cellulose nanofibers due to the inclusion of a hydrophilic structure. Specific examples of the hydrophilic structure 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, -SOM, -OSOM, -HMPO, and -MPO (wherein M represents an alkali metal or alkaline earth metal), primary to tertiary amines, and quaternary ammonium salts. Examples of the counter anion of the quaternary ammonium salt include halide ions such as hydroxide ion, fluoride ion, chloride ion, bromide ion, and iodide ion, as well as one or more hydrophilic groups selected from the group consisting of nitrate ion, formate ion, acetate ion, trifluoroacetate ion, p-toluenesulfonate ion, hexafluorophosphate, and tetrafluoroborate.

[0151] Examples of hydrophilic segments include polyethylene glycol segments, segments containing repeating units having a quaternary ammonium salt structure, polyvinyl alcohol segments, polyvinylpyrrolidone segments, polyacrylic acid segments, carboxyvinyl polymer segments, cationized guar gum segments, hydroxyethyl cellulose segments, methyl cellulose segments, carboxymethyl cellulose 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, 5 or more, 10 or more, or 15 or more. The longer the chain length, the higher the affinity with cellulose nanofibers. However, from the viewpoint of a balance with the desired properties (e.g., mechanical properties) of the resin molded article, the polyoxyethylene chain length may be 60 or less, 50 or less, 40 or less, 30 or less, or 20 or less.

[0152] Examples of hydrophobic segments include segments containing hydrocarbons, segments containing fluorocarbons, segments containing alkylene oxide units having 3 or more carbon atoms (e.g., PPG blocks), and segments containing polymer structures. Preferred hydrocarbon-containing segments include alkyl, alkenyl, alkyl ether, alkenyl ether, alkylphenyl ether, alkenylphenyl ether, rosin ester, bisphenol A, β-naphthyl, styrenated phenyl, and hydrogenated castor oil. The number of carbon atoms in the alkyl 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, 5 or more, 10 or more, 12 or more, or 16 or more. Preferred fluorocarbon-containing segments include linear or branched alkyl groups having 1 to 20 carbon atoms. Examples of the polymer structure-containing segment include acrylic polymers, styrene resins, vinyl chloride resins, vinylidene chloride resins, polyolefin resins, amino acid lactams including lactam ring-opening polymerization products, polymers composed of diamines and dicarboxylic acids, polyacetal resins, polycarbonate resins, polyester resins, polyphenylene sulfide resins, polysulfone resins, polyether ketone resins, polyimide resins, fluorine-containing resins, hydrophobic silicone resins, melamine resins, epoxy resins, and phenolic resins. These hydrophobic segments may have either a linear or branched structure. The hydrophobic segment may have a single chain structure or two or more chain structures. When the hydrophobic segment has two or more chain structures, it may have multiple types of hydrophobic groups.

[0153] The structure of the amphiphilic molecule is not particularly limited, but examples thereof include linear copolymers such as AB block copolymers, ABA block copolymers, and BAB block copolymers, where A is the hydrophilic segment and B is the hydrophobic segment, tri-branched copolymers containing A and B, tetra-branched copolymers containing A and B, star 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, the 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, the molecular structure may be a single type or a combination of two or more types.

[0154] (Surfactant) As the amphiphilic molecule, any of anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants can be used. The dispersant may be a polymer 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 alkyl aryl 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 esters, polyethylene glycol mono- or dilaurate esters, polyoxyethylene hydrogenated castor oil), glycerin fatty acid esters (e.g., glycerin monostearate, glycerin monooleate), sorbitan fatty acid esters (e.g., sorbitan monolaurate, sorbitan monostearate), and polyoxyethylene-polyoxypropylene block polymers.

[0156] The anionic surfactant (emulsifier) ​​may be a carboxylate, sulfonate, sulfate, phosphate, or the like. Examples of the carboxylate include aliphatic monocarboxylic acids and alkyl ether carboxylates; examples of the sulfonate include dialkyl sulfosuccinates, alkanesulfonates, alkylbenzenesulfonates, and alkylnaphthalenesulfonates; examples of the sulfate include alkyl sulfates and fat sulfate esters; and examples of the phosphate include alkyl phosphates and polyoxyethylene alkyl ether phosphates.

[0157] Examples of cationic surfactants include amine salts, amidoamine salts, quaternary ammonium salts, and imidazolinium salts. Specific examples include, but are not limited to, amine salt surfactants such as alkylamine salts, polyoxyethylene alkylamine salts, alkylamidoamine salts, aminoalcohol fatty acid derivatives, polyamine fatty acid derivatives, and imidazolines, and quaternary ammonium salt surfactants such as alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, alkylpyridinium salts, alkylisoquinolinium salts, and benzethonium chloride.

[0158] Examples of amphoteric surfactants include alkylamine oxides, alanines, imidazolinium betaines, amidobetaines, and acetic acid betaine. Specific examples include long-chain amine oxides, lauryl betaine, stearyl betaine, lauryl carboxymethyl hydroxyethyl imidazolinium betaine, lauryl dimethylamino acetic acid betaine, and fatty acid amidopropyl dimethylamino acetic 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 a hydroxyl group, a carboxyl group, an amino group, an ammonium group, a sulfonic acid group, a phosphate group, and the like. As the hydrophilic polymer, one or more selected from the group consisting of cellulose derivatives (hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, etc.), polyalkylene glycols, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, carboxyvinyl polymers, cationized guar gum, water-soluble polyurethanes, polymers containing a quaternary ammonium salt structure, amides, amines, and the like can be used. 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 nanofibers, and is 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] In one embodiment, the content of the dispersant in the resin composition components may be 0.1% by mass or more, or 0.5% by mass or more, or 1% by mass or more, and in one embodiment, 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-based elastomer is used to produce a resin composition, the mass ratio of the preliminary composition to the styrene-based elastomer in the resin composition components (preliminary composition / styrene-based elastomer) may be, in one embodiment, 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] [Vulcanizing Agent, Vulcanization Accelerator] When the resin composition component contains a liquid rubber, the resin composition component typically contains a vulcanizing agent and may optionally contain 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 component. Examples of vulcanizing agents that can be used 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 polymeric polysulfur compounds.

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

[0165] Examples of the vulcanization accelerator include sulfenamide-based, guanidine-based, thiuram-based, aldehyde-amine-based, aldehyde-ammonia-based, thiazole-based, thiourea-based, and dithiocarbamate-based accelerators. Zinc oxide, stearic acid, and the like may also be used as a vulcanization aid. The amount of the 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 the liquid rubber in the resin composition components.

[0166] [Rubber Additives] The resin composition components may contain various conventionally known rubber additives (stabilizers, softeners, antioxidants, etc.). As the rubber stabilizer, 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. Furthermore, as the rubber softener, one or more process oils, extender oils, etc. may be used. However, in one aspect, the resin composition of this embodiment is capable of forming a flexible molded body, and therefore, in one aspect, the resin composition components may not contain a rubber softener.

[0167] The vulcanizing agent, vulcanization accelerator, and rubber additives are typically added during the production of the resin composition, but the manner of addition is not limited to this.

[0168] <Additional Components of Resin Composition Components> The resin composition components may further contain additional components. Examples of the additional components include additional polymers, organic or inorganic fillers, heat stabilizers, antioxidants, antistatic agents, colorants, etc. The content 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, and may be, for example, 0.01 to 50% by mass, or 0.1 to 30% by mass.

[0169] <Production of Resin Composition> A resin composition according to one embodiment can be produced by mixing composition components that are a mixture containing cellulose nanofibers, an acid-modified styrene-based elastomer, and a styrene-based elastomer. A resin composition according to one embodiment can be produced by mixing composition components that are a mixture containing a tack inhibitor containing cellulose nanofibers and a styrene-based elastomer. In one embodiment, the mixing is heat kneading. That is, a method for producing a resin composition according to one embodiment includes a kneading step of heat kneading a mixture containing a styrene-based elastomer and cellulose nanofibers.

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

[0171] Examples of methods for producing a resin composition using an acid-modified styrene-based elastomer include: (1) a method comprising a first step of mixing cellulose nanofibers with an acid-modified styrene-based elastomer to obtain a preliminary composition, and a second step of mixing the preliminary composition with a styrene-based elastomer to obtain a resin composition; and (2) a method comprising a step of simultaneously mixing resin composition components containing cellulose nanofibers, an acid-modified styrene-based elastomer, and a styrene-based elastomer. When an acid-modified styrene-based elastomer is not used, the resin composition components containing cellulose nanofibers and a styrene-based elastomer may be simultaneously mixed in the above method (2). The mixing conditions are not particularly limited. For example, the resin composition may be obtained by mixing the components constituting the resin composition using a stirring means such as a rotation-revolution mixer, a planetary mixer, a propeller-type stirrer, a rotary stirrer, an electromagnetic stirrer, an open roll, a Banbury mixer, a kneader, a single-screw extruder, or a twin-screw extruder. Furthermore, stirring may be performed under heat to efficiently achieve shearing. In the above method (1), by combining the acid-modified styrene-based elastomer with the cellulose nanofibers in advance, the contact opportunity between the cellulose nanofibers and the styrene-based elastomer becomes more moderate and uniform, which can lead to better improvement in the physical properties of the resin composition.

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

[0173] [Drying step] In one embodiment, a dried product containing cellulose nanofibers can be produced by drying a cellulose nanofiber slurry. The dryer is not particularly limited, but examples include a kneader, planetary mixer, Henschel mixer, high-speed mixer, propeller mixer, ribbon mixer, single- or twin-screw extruder, Banbury mixer, freeze dryer, shelf dryer, spray dryer, fluidized bed dryer, and drum dryer.

[0174] The drying temperature may be, for example, 20°C or higher, or 30°C or higher, or 40°C or higher, or 50°C or higher from the viewpoint of drying efficiency, and of forming a dried body containing cellulose nanofibers with powder properties that are excellent in nano-dispersibility and macro-dispersibility of the cellulose nanofibers in the resin composition; and from the viewpoint of making thermal degradation of the cellulose nanofibers and additional components less likely to occur and 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, or 180°C or lower, or 160°C or lower, or 140°C or lower, or 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, by the surface temperature of the temperature-control 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 powder properties that are excellent in drying efficiency, nano-dispersibility, and macro-dispersibility of the cellulose nanofibers in the resin composition, the pressure may be -1 kPa or less, or -10 kPa or less, or -20 kPa or less, or -30 kPa or less, or -40 kPa or less, or -50 kPa or less, and from the viewpoint of avoiding excessive pulverization of the dried body containing cellulose nanofibers due to rapid drying of the slurry, the pressure may be -100 kPa or more, or -95 kPa or more, or -90 kPa or more.

[0176] From the viewpoint of process efficiency during drying, the concentration of cellulose nanofibers in the cellulose nanofiber slurry to be subjected to the drying step 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 maintaining good handleability by avoiding an excessive increase in the viscosity of the slurry and solidification due to aggregation, the concentration 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, and the cellulose nanofiber concentration in the slurry may be adjusted to the above-mentioned preferred range by concentrating such a dilute dispersion. Concentration can be achieved by methods such as suction filtration, pressure filtration, centrifugal deliquoring, and heating.

[0177] In one embodiment, the dried material containing cellulose nanofibers may contain a liquid polymer and / or dispersant, which may be added before, during, and / or after drying of 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 is preferably a solvent in which the liquid polymer and dispersant are soluble, and examples of such non-water-soluble solvents include chloroform, toluene, hexane, and cyclohexane.

[0178] [Liquid Medium Content] From the viewpoint of workability during kneading with the acid-modified styrene-based elastomer or the styrene-based elastomer, the liquid medium content of the dried material containing cellulose nanofibers may be 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 the tack suppression effect, a particularly preferred liquid medium content 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 production of the dried material 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 moisture meter.

[0179] [Average particle size] In one aspect, the average particle size of the dried material containing cellulose nanofibers is preferably 1 μm or more, or 10 μm or more, or 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 production, and is 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 of allowing the dried material containing cellulose nanofibers to easily disintegrate in the resin composition and the cellulose nanofibers to be well dispersed in the resin composition. The above average particle size is a value measured using a dynamic image analysis particle size distribution measuring device (CAMSIZER X2, manufactured by Microtrac).

[0180] [Loose bulk density] In one embodiment, the loose bulk density of the dried material containing cellulose nanofibers is preferably 0.01 g / cm from the viewpoints of good fluidity and excellent feedability of the dried material containing cellulose nanofibers and suppression of migration of the liquid polymer and / or dispersant to the resin composition. 3 or more, or 0.05 g / cm 3 or more, or 0.10 g / cm 3 or more, or 0.15 g / cm 3 or more, or 0.20 g / cm 3 or more, or 0.25 g / cm 3 or more, or 0.30 g / cm 3 or 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 The dry material containing cellulose nanofibers is preferably 0.85 g / cm3 or more, in that the dry material containing cellulose nanofibers can be easily disintegrated in the resin composition, allowing the cellulose nanofibers to be well dispersed in the resin composition, and the dry material containing cellulose nanofibers is not too heavy, so that poor mixing of the dry material containing cellulose nanofibers with the resin composition can be avoided. 3 or less, or 0.80 g / cm 3 or less, or 0.75 g / cm 3 The following is the result.

[0181] [Covered bulk density] In one embodiment, the compacted bulk density of the dried body containing cellulose nanofibers is controlled within a range useful for controlling the loose bulk density and compressibility within the ranges of the present disclosure, and in one embodiment, 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, preferably 0.95 g / cm 3 or less, or 0.9 g / cm 3 or less, or 0.85 g / cm 3 The following is the result.

[0182] [Degree of compression] The degree of compression is a value calculated by the formula: Degree of compression = (tough bulk density - loose bulk density) / tough bulk density. The loose bulk density and tough bulk density are values ​​measured by the methods described in the [Examples] section of this disclosure. In one aspect, the degree of compression represents the degree of bulk loss. In one aspect, the degree of compression of the dried 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, so that the fluidity of the dried material containing cellulose nanofibers is not too high. Furthermore, from the viewpoints of good fluidity and excellent feedability of the dried material containing cellulose nanofibers, excellent handleability (specifically, less scattering, floating, or dust formation), good dispersion of the dried material containing cellulose nanofibers in the resin composition, and suppression of 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 loose bulk density, compacted bulk density, and compressibility are measured using a powder tester (model number: PT-X) manufactured by Hosokawa Micron Corp. The compacted bulk density is measured by tapping 180 times.

[0184] As a more specific example of the order of steps, the following can be mentioned as an example when an acid-modified styrene-based elastomer is used. (i) preparing a slurry containing cellulose nanofibers and optionally a liquid polymer and / or a dispersant → drying to prepare a dried body → preparing a preliminary composition containing the dried body and an acid-modified styrene-based elastomer → preparing a resin composition containing the preliminary composition and a styrene-based elastomer. (ii) preparing a slurry containing cellulose nanofibers and optionally a liquid polymer and / or a dispersant → drying to prepare a dried body → preparing a preliminary composition containing the dried body, an acid-modified styrene-based elastomer, and a styrene-based elastomer → preparing a resin composition containing the preliminary composition and a styrene-based elastomer. (iii) preparing a slurry containing cellulose nanofibers, an acid-modified styrene-based elastomer, and optionally a liquid polymer and / or a dispersant → drying to prepare a dried body → preparing a resin composition containing the dried body and a styrene-based elastomer. (iv) preparing a slurry containing cellulose nanofibers, an acid-modified styrene-based elastomer, a styrene-based elastomer, and optionally a liquid polymer and / or a dispersant → drying to prepare a resin composition.

[0185] In addition, in an embodiment in which a tack inhibitor containing cellulose nanofibers is used, the following can also be mentioned. (i) preparing a slurry containing cellulose nanofibers and optionally a liquid polymer and / or a dispersant → drying to prepare a dried body → preparing a preliminary composition containing the dried body and an acid-modified styrene-based elastomer → preparing a resin composition containing the preliminary composition and a styrene-based elastomer. (ii) preparing a slurry containing cellulose nanofibers and optionally a liquid polymer and / or a dispersant → drying to prepare a dried body → preparing a preliminary composition containing the dried body, an acid-modified styrene-based elastomer, and a styrene-based elastomer → preparing a resin composition containing the preliminary composition and a styrene-based elastomer. (iii) preparing a slurry containing cellulose nanofibers and optionally a liquid polymer and / or a dispersant → drying to prepare a dried body → preparing a resin composition containing the dried body, an acid-modified styrene-based elastomer, and a styrene-based elastomer. (iv) preparing a slurry containing cellulose nanofibers, an acid-modified styrene-based elastomer, and optionally a liquid polymer and / or a dispersant → drying to prepare a dried body → preparing a resin composition containing the dried body and a styrene-based elastomer. (v) A slurry containing cellulose nanofibers, an acid-modified styrene-based elastomer, a styrene-based elastomer, and optionally a liquid polymer and / or a dispersant is prepared, and then dried to prepare a resin composition.

[0186] The resin composition may be molded into a desired shape, either alone or together with other components, to produce a desired molded article. The method for combining the components and the molding method are not particularly limited and may be selected depending on the desired molded article. Molding is typically performed by melt molding, such as injection molding, extrusion molding, extrusion profile molding, blow molding, or compression molding.

[0187] In one aspect, the molding method may be a profile molding. That is, in one aspect, the resin molded article of this embodiment may be a profile molded article. Another aspect of the present invention provides a method for producing a profile extrusion molded article, including a step of profile extruding the resin composition of this embodiment. A known profile extrusion molding method can be used for the profile extrusion molding. A specific example of a profile extrusion molding method includes feeding a resin composition into an extruder, kneading it while heating it inside, and extruding it through a profile extrusion die to obtain an uncooled resin molded article. Next, a method is exemplified in which the uncooled resin molded article is continuously introduced into a cooling zone and cooled to obtain a profile extrusion molded article.

[0188] Another method is to perform melt kneading to obtain a resin composition, extrude the resin using the die of the kneader as a die for profile extrusion to obtain an uncooled resin molded product, and then continuously introduce the uncooled resin molded product into a cooling zone to cool it and obtain a profile extrusion molded product.

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

[0190] The cross-sectional shape of the profile extrusion molded product is not particularly limited, but preferred cross-sectional shapes include sheet, pipe, tube, and angular shapes. 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 or tube 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. Furthermore, the minimum radius of curvature on the valley side of the corner can be 0.1 mm.

[0191] <3D Printing Material> A preferred example of the use of the resin composition of this embodiment is a 3D printing material. One aspect of the present invention provides a 3D printing material composed of the resin composition of this embodiment. The 3D printing material may be formed into a desired form selected from various forms such as pellets, filaments, and powder. In one aspect, the 3D printing material has the form of a filament or powder.

[0192] The 3D printing modeling material of this embodiment has the advantage that its ability to inhibit cellulose nanofiber aggregation prevents dripping (drawdown) due to its own weight from the nozzle when molding into a 3D printing modeling material or during modeling.

[0193] The resin composition can be molded into a desired shape of a 3D printing material by any known method. For example, the filament may be a monofilament or a multifilament, but a monofilament is preferred for ease of molding.

[0194] The diameter of the filamentary modeling 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 filamentary modeling material is preferably greater than 1 m, more preferably greater than 10 m, more preferably greater than 100 m, and most preferably greater than 300 m. Controlling the shape of the filamentary modeling material within this range allows for a wide selection of applicable 3D printers, and makes it possible to appropriately design the modeling time, size, and precision of the modeled object. In one embodiment, the length of the filamentary modeling material may be 20,000 m or less.

[0195] In one embodiment, the filamentous modeling material can be produced by heating and melting a resin composition, passing it through a fine hole in a nozzle or the like, cooling it, and winding it up. The diameter of the fine hole can be selected appropriately depending on the diameter of the filament and the winding speed. From the viewpoints of production efficiency and the frequency of thread breakage, 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. The cooling method can be selected appropriately from known methods such as air cooling and water cooling. However, air cooling is preferred from the viewpoint of preventing water absorption due to the hydrophilicity of cellulose nanofibers. From the viewpoints of production efficiency and the frequency of thread breakage, the winding speed of the filament is preferably 0.1 to 10 m / s, more preferably 0.15 to 5 m / s, and most preferably 0.2 to 1 m / s. The production apparatus for the filamentous modeling material and the production apparatus for the resin composition may be the same or different.

[0196] The particle size, particle shape, and aspect ratio of the powder modeling 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 viewpoints of handling as a modeling material and surface smoothness of the modeled object. The particle shape may be spherical or irregular, but irregular shapes are preferred from the viewpoint of suppressing voids during modeling. The aspect ratio is preferably 1.001 to 3.0, preferably 1.01 to 2.0, and most preferably 1.1 to 1.8, from the viewpoint of suppressing voids by reducing interparticle gaps.

[0197] In one embodiment, the powdered modeling material can be produced by pulverizing or reprecipitating a resin composition. The method for pulverizing the resin composition is not particularly limited, and may be wet pulverization, dry pulverization, cryo-pulverization, freeze-pulverization, heat-pulverization, etc. A pulverizing medium may be used to control the shape of the powdered modeling material.

[0198] <Shaped object> One aspect of the present invention provides a shaped object formed by using a 3D printer to shape the resin composition (e.g., resin composition pellets) or 3D printing material of the present embodiment. Another aspect of the present invention provides a method for manufacturing a shaped object, including a step of using a 3D printer to shape the resin composition or 3D printing material of the present embodiment. 3D printer modeling methods include fused deposition modeling, stereolithography, material jetting, powder bonding, and powder bed fusion. When a filamentary modeling material is used, fused deposition modeling is preferred, and when a powdered modeling material is used, powder bonding and powder bed fusion are preferred.

[0199] <Uses of 3D Printing Materials and Shaped Products> The shaped product may be used directly for various applications, or may be molded into a desired shape alone or with other components to produce a desired molded product. The method of combining the components and the molding method are not particularly limited and may be selected depending on the desired molded product. Examples of molding methods that can be used include, but are not limited to, cutting molding and foam molding. Shaped products or molded products are useful as replacements for steel plates, fiber-reinforced plastics (e.g., carbon fiber-reinforced plastics, glass fiber-reinforced plastics, etc.), resin composites containing inorganic fillers, etc. Suitable uses of 3D printing materials, shaped products, and molded products include industrial machine parts, general machine parts, automobile, railway, vehicle, ship, and aerospace-related parts, electronic and electrical parts, construction and civil engineering materials, household goods, sports and leisure goods, wind power generation housing components, containers and packaging materials, etc.

[0200] The obtained molded articles can be used for a variety of purposes, such as automobile parts, electrical and electronic parts, building materials, parts for daily life, cosmetics, and medical use, rails, pipes, sashes, door frames, window frames, handrails, decking materials, fences, and various building materials.

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

[0202] Examples of electric and electronic parts include parts or members of devices that are made of resin molded bodies and have many metal contacts, such as parts or members of audio equipment, video equipment, office automation equipment such as telephones, copy machines, facsimiles, word processors, and computers, and parts or members of toys, specifically chassis, gears, levers, cams, pulleys, and bearings.

[0203] Furthermore, it can be suitably used in a wide range of lifestyle, cosmetic and medical parts, such as lighting fixtures, fittings, pipes, cocks, faucets, toilet peripheral parts and other building materials and piping parts, fasteners, stationery, lip balm and lipstick containers, cleaning devices, water purifiers, spray nozzles, spray containers, aerosol containers, general containers and syringe needle holders.

[0204] Among these, it is more preferably usable for gears, which are used in high temperature environments and subject to high loads.

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

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

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

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

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

[0210] <<Resin Molded Article>> One aspect of the present invention provides a resin molded article obtained by molding the resin composition of the present 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 parts, construction and civil engineering materials, daily necessities, sports and leisure goods, housing components for wind power generation, containers and packaging components, etc. Examples of applications include automobile parts (for example, exterior parts such as tires, bumpers, fenders, door panels, various moldings, emblems, engine hoods, wheel caps, roofs, spoilers, and various aero parts, and interior parts such as instrument panels, console boxes, and trim), battery parts (for example, automotive secondary battery parts, lithium ion secondary battery parts, fuel cases for solid methanol batteries, and fuel cell piping), electronic and electrical equipment parts (for example, parts for various computers and their peripheral devices, junction boxes, various connectors, various office automation equipment, televisions, videos, disc players, chassis, refrigerators, air conditioners, and liquid crystal projectors), household goods (for example, shoe outsoles), anti-vibration rubber, and conveyor belts.

[0211] The present disclosure also includes the following items. <Item A> [Item 1] A resin composition comprising an acid-modified styrene-based elastomer, a styrene-based elastomer, and cellulose nanofibers, wherein the total amount of the acid-modified styrene-based elastomer and the styrene-based elastomer is 60% by mass or more, based on 100% by mass of the resin composition. [Item 2] The resin composition according to Item 1, wherein the acid-modified styrene-based elastomer and the styrene-based elastomer are compatible with each other. [Item 3] The resin composition according to Item 1 or 2, comprising 0.5 to 50 parts by mass of the acid-modified styrene-based elastomer per 100 parts by mass of the styrene-based elastomer. [Item 4] The 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 nanofibers. [Item 5] The resin composition according to any one of Items 1 to 4, comprising 0.5 to 45 parts by mass of the acid-modified styrene-based elastomer per 1 part by mass of the cellulose nanofibers. [Item 6] The resin composition according to any one of items 1 to 5, comprising 0.5% by mass to 50% by mass of the acid-modified styrene-based elastomer. [Item 7] The resin composition according to any one of items 1 to 6, comprising 10% by mass to 98.8% by mass of the styrene-based elastomer. [Item 8] The resin composition according to any one of items 1 to 7, comprising 0.1% by mass 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-modified styrene-based elastomer has an acid modification rate of 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-based elastomer is an aromatic vinyl compound-conjugated diene compound block copolymer or an acid-modified product of a styrene-based elastomer that is a hydrogenated product 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 product thereof.[Item 13] The resin composition according to any one of items 1 to 12, wherein the melt mass flow rate of the styrene 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% by mass 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 elastomer is 10% by mass 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 elastomer to the styrene unit ratio of the acid-modified styrene elastomer (styrene ratio of styrene elastomer / styrene ratio of acid-modified styrene 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-based elastomer is 10,000 to 500,000, and the number average molecular weight of the styrene-based 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-based 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-based elastomer is 0.2% by mass 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 1,000 nm. [Item 21] The resin composition according to any one of items 1 to 20, wherein the thermal decomposition onset temperature of the cellulose nanofibers is 250°C or higher. [Item 22] The specific surface area of ​​the cellulose nanofiber is 10 m. 2 / g to 200m 2 / g. [Item 23] The resin composition according to any one of items 1 to 22, further comprising a polyoxyethylene unit-containing polymer. [Item 24] The resin composition according to any one of items 1 to 23, further comprising a liquid polymer. [Item 25] A method for producing the resin composition according to any one of items 1 to 24, comprising heating and kneading a mixture containing the acid-modified styrene-based elastomer, the styrene-based elastomer, and the cellulose nanofibers. [Item 26] A resin molded article obtained by molding the resin composition according to any one of items 1 to 24. [Item 27] ​​The resin molded article according to item 26, which is a profile extrusion molded article. [Item 28] A method for producing a profile extrusion molded article, comprising a step of profile extruding the resin composition according to any one of items 1 to 24. [Item 29] A modeling material for 3D printing, comprising the resin composition according to any one of items 1 to 24. [Item 30] The modeling material for 3D printing according to item 29, which has the form of a filament or powder. [Item 31] A shaped object produced by using a 3D printer to model the resin composition according to any one of items 1 to 24 or the 3D printing material according to item 29 or 30. [Item 32] A method for producing a shaped object, comprising the step of using a 3D printer to model the resin composition according to any one of items 1 to 24 or the 3D printing material according to item 29 or 30.

[0212] <Item B> [Item 1] A resin composition comprising a styrene-based elastomer and a tack inhibitor containing cellulose nanofibers. [Item 2] The resin composition according to item 1, containing 10% by mass or more of the styrene-based elastomer. [Item 3] The resin composition according to item 1 or 2, containing 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 containing an acid-modified styrene-based elastomer. [Item 5] The resin composition according to any one of items 1 to 4, wherein the styrene-based elastomer is unmodified. [Item 6] The resin composition according to any one of items 1 to 5, containing 0.5 parts by mass to 250 parts by mass of the styrene-based elastomer per part by mass of the cellulose nanofibers. [Item 7] The resin composition according to any one of items 1 to 6, wherein the styrene-based 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 styrene 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 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 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 onset temperature of the cellulose nanofibers is 250°C or higher. [Item 13] The resin composition according to any one of items 1 to 11, wherein the specific surface area of ​​the cellulose nanofibers is 10 m 2 / g to 200m 2 / g. [Item 14] The 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] The resin composition according to any one of items 1 to 15, further comprising a liquid polymer. [Item 17] A method for producing the resin composition according to any one of items 1 to 16, 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 in a dried state with a liquid medium content of 7% by mass or less. [Item 19] A resin molded article obtained by molding the resin composition according to any one of items 1 to 16. [Item 20] The resin molded article according to item 19, which is a profile extrusion molded article. [Item 21] A method for producing a profile extrusion molded article, comprising a step of profile extruding the resin composition according to any one of items 1 to 16. [Item 22] A 3D printing modeling material composed of the resin composition according to any one of items 1 to 16. [Item 23] The 3D printing modeling material according to item 22, which has the form of a filament or powder. [Item 24] A modeled object produced by modeling the resin composition according to any one of items 1 to 16 or the 3D printing modeling material according to item 22 or 23 using a 3D printer. [Item 25] A method for producing a modeled object, comprising the step of modeling the resin composition according to any one of items 1 to 16 or the 3D printing modeling material according to item 22 or 23 using a 3D printer.

[0213] The following examples further illustrate exemplary embodiments of the present invention, but the present invention is not limited to these examples.

[0214] <Evaluation Methods> <Acid-Modified Styrenic Elastomer and Styrenic Elastomer> [Acid Modification Rate (Maleication Rate)] The values ​​shown in the product catalog are shown.

[0215] [Styrene unit ratio] The value shown is from the product catalog.

[0216] [MFR at 230°C and 2.16 kg] The values ​​shown in the product catalog are shown.

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

[0218] <Cellulose nanofibers> The following evaluations were carried out on the cellulose nanofibers. [Preparation of porous sheet] First, the concentrated cake was added to tert-butanol, and further dispersion treatment was carried out using a mixer or the like until no aggregates were present. The concentration was adjusted to 0.5% by mass per 0.5 g of cellulose nanofiber solids. 100 g of the obtained tert-butanol dispersion was filtered on filter paper. Without peeling the filtered material from the filter paper, it was sandwiched together with the filter paper between two larger pieces of filter paper, and dried for 5 minutes in an oven at 150°C while pressing down the edges of the larger filter paper with weights. The filter paper was then peeled off to obtain a porous sheet with little distortion. The air resistance of this sheet was 10 g / m2. 2 The porous sheet was used as a measurement sample. The basis weight W (g / m 2 After measuring the air permeability, the air permeability resistance R (sec / 100 ml) was measured using an Oken type air permeability resistance tester (manufactured by Asahi Seiko Co., Ltd., model EG01). 2 The value per unit area was calculated. 2 Air resistance per unit area (sec / 100 ml) = R / W x 10

[0219] [Weight-average molecular weight (Mw), number-average molecular weight (Mn), and Mw / Mn ratio] 0.88 g of the porous sheet was weighed, cut into small pieces with scissors, and then gently stirred. 20 mL of pure water was added and the mixture was left for one day. Next, the water and solids were separated by centrifugation. 20 mL of acetone was then added, gently stirred, and the mixture was left for one day. Next, the acetone and solids were separated by centrifugation. 20 mL of N,N-dimethylacetamide was then added, gently stirred, and the mixture was left for one day. Again, the N,N-dimethylacetamide and solids were separated by centrifugation, and then 20 mL of N,N-dimethylacetamide was added, gently stirred, and the mixture was left for one day. The N,N-dimethylacetamide and solids were separated by centrifugation, and 19.2 g of an N,N-dimethylacetamide solution prepared so that lithium chloride was 8 mass percent was added to the solids. The mixture was stirred with a stirrer, and dissolution was confirmed visually. The solution in which the cellulose nanofibers were dissolved 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 HLC-8120 Column: TSKgel SuperAWM-H (6.0 mm I.D. x 15 cm) x 2 Detector: RI detector Eluent: N,N-dimethylacetamide (lithium chloride 0.2%) Flow rate: 0.6 mL / min Calibration curve: Pullulan equivalent

[0220] [Average alkali-soluble polysaccharide content] The alkali-soluble polysaccharide content was determined by subtracting the α-cellulose content from the holocellulose content (Wise method) using the method described in a non-patent document for cellulose nanofibers (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 contents was taken as the average alkali-soluble polysaccharide content of the cellulose nanofibers.

[0221] [Average Acid-Insoluble Component Content] The acid-insoluble component was quantified for cellulose nanofibers using the Clason method described in the non-patent literature (Wood Science Experiment Manual, edited by the Japan Wood Research Society, pp. 92-97, 2000). Bone-dried cellulose nanofibers were precisely weighed, placed in a designated container, and 72% by mass of concentrated sulfuric acid was added. The contents were appropriately pressed with a glass rod to homogenize them, and then autoclaved to dissolve the cellulose and hemicellulose in the acid solution. After allowing to cool, the contents were filtered through glass fiber filter paper, and the acid-insoluble component was obtained as a residue. The acid-insoluble component content was calculated from the weight of the acid-insoluble component, and the number average of the acid-insoluble component contents calculated for the three samples was used as the average acid-insoluble component content.

[0222] [Crystallization degree] The porous sheet was subjected to X-ray diffraction measurement, and the crystallinity was calculated by the following formula: Crystallinity (%)=[I (200) -I (amorphous) ] / I (200) ×100 I (200) : Diffraction peak intensity due to the 200 plane (2θ = 22.5°) in cellulose type I crystal (amorphous) : The halo peak intensity due to amorphous in cellulose type I crystals, which is 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) Apparatus: MiniFlex (manufactured by Rigaku Corporation) Operation axis: 2θ / θ Radiation source: CuKα Measurement method: Continuous Voltage: 40 kV Current: 15 mA Start angle: 2θ = 5° End angle: 2θ = 30° Sampling width: 0.020° Scan rate: 2.0° / min Sample: A porous sheet was attached to a sample holder

[0223] [Number Average Fiber Diameter] The concentrated cake was diluted to 0.01% by mass with tert-butanol and dispersed using a high-shear homogenizer (manufactured by IKA, trade name "Ultra Turrax T18") under processing conditions of 15,000 rpm for 3 minutes. The resulting dispersion was cast onto an osmium-deposited silicon substrate and air-dried, and then measured with a high-resolution scanning electron microscope (manufactured by Hitachi High-Technologies Corporation, Regulus 8220). The measurement was performed by adjusting the magnification so that at least 100 cellulose nanofibers were observed, and the diameters (D) of 100 randomly selected cellulose nanofibers were measured. The arithmetic average of the 100 cellulose nanofibers was calculated as the number average fiber diameter.

[0224] [Aspect Ratio] The number-average fiber length L, number-average fiber diameter D, and number-average aspect ratio (L / D) of the cellulose nanofibers in the resin composition are values ​​measured using an optical microscope according to the following procedure. A resin composition prepared by heat-kneading a resin and cellulose nanofibers was used as a measurement sample, and the cellulose nanofibers in the resin were measured using an optical microscope while heated to 220°C on a hot stage. Specifically, the lengths and diameters of 200 randomly selected cellulose nanofibers were measured, and the ratios were calculated. The respective number average values ​​were taken 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] Approximately 0.2 g of the porous sheet was dried under vacuum at 120°C for 5 hours using a specific surface area / pore distribution measuring device (Nova-4200e, manufactured by Quantachrome Instruments). Then, the amount of nitrogen gas adsorbed at the boiling point of liquid nitrogen was measured at 5 points in the range of relative vapor pressure (P / P) of 0.05 to 0.2 (multipoint method). Then, the BET specific surface area (m 2 / g) was calculated.

[0226] [Thermal decomposition start temperature (T D) )] Thermal analysis of the porous sheet was carried out by the following measurement method. Apparatus: Thermo plus EVO2 manufactured by Rigaku Corporation Sample: 10 mg of circular pieces cut out from the porous sheet were placed in an aluminum sample pan in a stack. Sample amount: 10 mg Measurement conditions: In a nitrogen flow of 100 ml / min, the temperature was increased from room temperature to 150°C at a rate of 10°C / min, and after holding at 150°C for 1 hour, the temperature was increased to 450°C at a rate of 10°C / min. T D Calculation method: The calculation was performed from a graph with the horizontal axis being temperature and the vertical axis being weight residual rate %. The temperature was further increased from the weight (weight loss 0 wt%) of the porous sheet at 150°C (a state where moisture was almost completely removed) as the starting point, and a straight line was obtained that passed through the temperatures at 1 wt% weight loss and 2 wt% weight loss. The temperature at the point where this straight line intersects with the horizontal line (baseline) that passes through the starting point of 0 wt% weight loss was determined as the thermal decomposition onset temperature (T D )

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

[0228] [Weight loss rate at 250°C] Apparatus: Thermo plus EVO2 manufactured by Rigaku Corporation Sample: Circular cutouts from the porous sheet were placed in an aluminum sample pan in layers of 10 mg. Sample amount: 10 mg Measurement conditions: In a nitrogen flow of 100 ml / min, the temperature was increased from room temperature to 150°C at a rate of 10°C / min, and then held at 150°C for 1 hour. The temperature was increased from 150°C to 250°C at a rate of 10°C / min, and then 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 taken as W1, and the weight loss rate at 250°C (%) was calculated using the following formula: (W0-W1) / W0} x 100

[0229] [Weight increase rate of cellulose nanofibers separated from resin composition using THF] Separation of cellulose nanofibers from resin compositions can be easily performed by methods commonly used by those skilled in the art. Separation was performed as follows. Approximately 1.5 g of broken pieces of the resin composition was used, and the broken resin pieces were dissolved in 70 ml of THF to separate them into soluble (resin) and insoluble (cellulose nanofibers and resin adsorbed on the fiber surface). The insoluble pieces were filtered through filter paper, and then dried and concentrated in a vacuum dryer at 80°C for 3 hours, and the weight of the insoluble pieces was measured. The weight increase rate of the cellulose nanofibers was calculated using the following formula. The theoretical weight below refers to the charged weight of the cellulose nanofibers. Weight increase rate of cellulose nanofibers (%) = (weight of insoluble - theoretical weight of cellulose nanofibers contained in the broken pieces) ÷ theoretical weight of cellulose nanofibers contained in the broken pieces × 100

[0230] <Resin Composition> [Degree of Whitening at Fracture (Void Amount)] Using a test specimen after testing using the tensile test method of JIS K-6251, the MD / TD cross section of the fracture site (ND 2 mm × TD 3 mm × MD 4 mm) was observed using X-ray CT. Apparatus: Bruker X-CT Skyscan 1272 <Conditions> Tube voltage: 40 kV, Tube current: 100 μA, Number of pixels: 2 k (2452 × 1640 pix), Pixel resolution: 2.4 μm, Number of accumulations: 4, Scan: every 0.4°, Analysis processing: Smoothing (Kuwahara filter 2 pix) Next, the observed image was binarized to extract void locations, and the percentage (%) of the total void volume 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, objects of 50 pixels or more on the xy cross section are deemed to be foreign matter or artifacts derived therefrom and removed (Evaluation criteria) Poor: 1% or more Passable: 0.5% or more and less than 1% Good: 0.02% or more and less than 0.5% Excellent: Less than 0.02%

[0232] [Tensile Stress at 400% Strain, Tensile Modulus at 50 to 100% Strain, Maximum Tensile Stress, and Strain] Using the tensile testing method of JIS K-6251, the 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, tensile modulus at 50 to 100% strain (the increment of 100% modulus relative to 50% modulus divided by the strain increment (100% - 50%)), maximum tensile stress, and strain at break were determined.

[0233] [Colorability] The color of the molded dumbbells was visually evaluated. (Evaluation criteria) Poor: Caramel color Fair: Light caramel color Good: Milky white Excellent: White or transparent

[0234] [Surface fuzzing of strands] The surface condition of the extruded strands was visually evaluated. (Evaluation criteria) Poor: No smooth areas, with severe surface irregularities. Fair: A surface condition where smooth areas and surface irregularities are present in equal parts. Good: A surface condition where slight fuzzing is observed on the surface. Excellent: A surface condition where no fuzzing is observed at all.

[0235] [Tackiness] The tack strength was measured using a tack tester TAC-II manufactured by Rhesca Co., Ltd. The measurement mode used was Constant Load, which pushes the probe in to a set pressure value and continues to control the pressure value to be maintained until a set time has elapsed. Specifically, the tack strength was measured on a sample of 19.625 mm2 in area. 2 A stainless steel probe having a flat surface of 120 mm / min was brought into contact with the surface of a measurement sample under the conditions of a probe moving speed of 120 mm / min, a pressure (load) of 600 gf, and a pressure time of 60 seconds, and the flat surface of the stainless steel probe was then peeled upward at a probe moving speed (peeling speed) of 600 mm / min. The tack peak value on the surface of the resin composition was measured 10 times by a probe tack test, and the average value of the 10 measurements divided by the area of ​​the flat surface of the probe was used as the tack strength. The measurement was carried out at 23°C.

[0236] [Tensile stress, maximum tensile stress, and strain at 400% strain] A tensile test was performed using an ISO 37 type 3 test piece at a temperature of 23° C. and a relative humidity of 50% at a tension speed of 5 mm / min. The arithmetic average of five data points for the tensile stress at 400% strain, the maximum tensile stress, and the strain at break was calculated.

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

[0238] <Acid-modified styrene-based elastomers> Acid-modified styrene-based elastomer 1: maleic acid-modified SEBS, manufactured by Asahi Kasei Corporation, Tuftec M1943, MFR: 6.5 g / 10 min (230°C, 2.16 kg) Acid-modified styrene-based elastomer 2: maleic acid-modified SEBS, manufactured by Asahi Kasei Corporation, Tuftec M1913, MFR: 6.5 g / 10 min (230°C, 2.16 kg) Acid-modified styrene-based elastomer 3: maleic acid-modified SEBS, manufactured by Asahi Kasei Corporation, Tuftec M1911, MFR: 4.2 g / 10 min (230°C, 2.16 kg)

[0239] <Cellulose nanofibers (unmodified CNF)> Three parts by mass of cotton linter pulp was immersed in 27 parts by mass of water and dispersed using a pulper. 30 parts by mass of the pulper-treated cotton linter pulp slurry (including 3 parts by mass of cotton linter pulp) was added to 170 parts by mass of water and dispersed in water (solid content: 1.5% by mass). The aqueous dispersion was then beaten for 30 minutes using an SDR14 lab refiner (pressure type disc type) manufactured by Aikawa Iron Works Co., Ltd., with a disc clearance of 1 mm. Subsequently, thorough beating was performed under conditions where the clearance was reduced to a level close to zero, yielding a beaten aqueous dispersion (solid content concentration: 1.5% by mass). The resulting beaten aqueous dispersion was then subjected to a high-pressure homogenizer (NSO15H manufactured by Niro Soavi, Italy) for 10 passes at an operating pressure of 100 MPa to obtain a cellulose nanofiber slurry (solid content concentration: 1.5% by mass). The mixture was then concentrated to a solids content of 10% by mass using a dehydrator to obtain a cake of cellulose nanofibers. The properties of the cellulose nanofibers were as follows: Weight average molecular weight (Mw): 380,000 Number average molecular weight (Mn): 80,000 Average content of alkali-soluble polysaccharides: 3.8% Average content of acid-insoluble components: 3.1% Degree of crystallinity: 85% Number average fiber diameter: 75 nm Specific surface area: 34 m 2 / g Thermal decomposition onset temperature (T D ): 283°C 1wt% weight loss temperature: 297°C 250°C Weight loss rate: 2.8%

[0240] <Dispersant> Polyethylene glycol: PEG 6000, manufactured by Sanyo Chemical Industries, Ltd.

[0241] <Liquid Polymer> Liquid polybutadiene: RICON 184 manufactured by Cray Valley, viscosity at 25°C: 75,000 mPa·s

[0242] <<Production of Resin Composition>> <Example 1> Cellulose nanofiber cake, RICON 184, and PEG 6000 were blended in a ratio of 7:4:3 by solids weight, and the mixture was stirred in a planetary mixer (model: ACM-5LVT: paddle type) manufactured by Kodaira Manufacturing Co., Ltd. under conditions of a jacket temperature of 80°C and 307 rpm, while the pressure was reduced to -90 kPa using a vacuum pump. Drying under reduced pressure was carried out until the product temperature reached 70°C, yielding a cellulose nanofiber powder. The resulting cellulose nanofiber powder, SEBS, and acid-modified styrene-based elastomer 1 were blended in the proportions shown in Table 1, and the mixture was melted for 5 minutes at 200°C and 200 rpm in a batch-type twin-screw kneader (Explore manufactured by DSM). Test specimens (ISO 37 type 3) were produced using a dedicated benchtop injection molding machine (manufactured by DSM) at a mold temperature of 80°C.

[0243] Examples 2 to 11, Comparative Examples 1 to 3 Resin compositions were obtained in the same manner as in Example 1, except that the formulation was changed as shown in Table 1.

[0244]

[0245] The resin composition according to the present disclosure can form molded articles having good physical properties, and therefore can be suitably applied to a wide range of uses, such as industrial machine parts, general machine parts, automobile, railway, vehicle, ship, and aerospace related parts, electronic and electrical parts, construction and civil engineering materials, daily necessities, sports and leisure goods, housing components for wind power generation, and container and packaging components.

Claims

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

2. A resin composition comprising a thermoplastic elastomer and cellulose nanofibers, wherein 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, and the amount of the thermoplastic elastomer in 100% by mass of the resin composition is 60% by mass or more.

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

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

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

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

7. The resin composition contains a styrenic elastomer as the thermoplastic elastomer, and the amount of the styrenic elastomer is 0.5 parts by mass to 250 parts by mass with respect to 1 part by mass of the cellulose nanofiber. The resin composition according to any one of claims 1 to 3.

8. The resin composition contains an acid-modified styrenic elastomer as the thermoplastic elastomer, and the amount of the acid-modified styrenic elastomer is 0.5 parts by mass to 45 parts by mass with respect to 1 part by mass of the cellulose nanofiber. The resin composition according to any one of claims 1 to 3.

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

10. The resin composition contains a styrenic elastomer as the thermoplastic elastomer, and the amount of the styrenic elastomer is 10% by mass to 98.8% by mass in 100% by mass of the resin composition. The resin composition according to any one of claims 1 to 3.

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

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

13. The resin composition contains a styrenic elastomer as the thermoplastic elastomer, and the styrenic elastomer is an unmodified product. The resin composition according to any one of claims 1 to 3.

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

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

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

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

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

19. The resin composition contains an acid-modified styrenic elastomer and a styrenic elastomer as the thermoplastic elastomer, and the ratio of the styrene unit ratio of the styrenic elastomer to the styrene unit ratio of the acid-modified styrenic elastomer (styrene ratio of the styrenic elastomer / styrene ratio of the acid-modified styrenic elastomer) is 0.3 to 2.

5. The resin composition according to any one of claims 1 to 3.

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

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

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

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 start temperature of the cellulose nanofibers is 250 °C or higher.

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

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

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

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

29. The method according to claim 28, wherein the weight increase rate of the cellulose nanofibers after heat-kneading with respect to the cellulose nanofibers before heat-kneading is 190% to 600%.

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

31. The resin molded article according to claim 30, which is a profile extrusion molded article.

32. A method for producing a profile extrusion molded article, the method including a step of profile extruding the resin composition according to any one of claims 1 to 3.

33. A modeling material for 3D printing, which is composed of the resin composition according to any one of claims 1 to 3.

34. The modeling material for 3D printing according to claim 33, which has a filament or powder form.

35. A modeled article formed by modeling the resin composition according to any one of claims 1 to 3 with a 3D printer.

36. A modeled article formed by modeling the modeling material for 3D printing according to claim 33 with a 3D printer.

37. A method for producing a modeled article, the method including a step of modeling the resin composition according to any one of claims 1 to 3 with a 3D printer.

38. A method for manufacturing a shaped article, the method comprising a step of shaping the 3D printing shaped 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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