Resin composition

Abstract

In one embodiment, a resin composition capable of forming a resin molded body that exhibits advantageous properties (good rubber elasticity, weather resistance, chemical resistance, etc.) inherent to styrene elastomers, and that also has excellent tensile strength, tensile elastic modulus, and / or tensile elongation at break, and further has few adverse conditions such as whitening and coloring, a method for producing the same, and a molded body formed by molding the resin composition are provided. In one embodiment, a resin composition is provided that is a resin composition containing a thermoplastic elastomer and cellulose nanofiber, wherein the thermoplastic elastomer contains an acid-modified styrene elastomer and a styrene elastomer, and the amount of the thermoplastic elastomer is 60% by mass or more in 100% by mass of the resin composition.

Description

Technical Field

[0001] This invention relates to resin compositions comprising styrene-based elastomers. Background Technology

[0002] Thermoplastic elastomers exhibit rubber-like elasticity and can be melt-molded using the same methods as thermoplastic resins, thus they have historically been used in a wide range of applications. Known thermoplastic elastomers include styrene-based, olefin-based, polyurethane-based, polyester-based, polyamide-based, acrylic-based, and polyvinyl chloride-based thermoplastic elastomers. Among these, styrene-based elastomers, due to their excellent weather resistance and chemical resistance, are used not only in sealing materials but also as modifiers and additives for various materials.

[0003] In resin molded articles, a high balance of various properties desired for different applications, such as mechanical strength, flexibility, abrasion resistance, and processability, is required. To enhance these properties, fillers are typically included in resin molded articles. In recent years, due to increased awareness of environmental issues, the utilization of cellulose as a low-gravity and renewable material as a filler in resin molded articles is being explored. Among these, cellulose nanofibers, when combined with various resins to form resin molded articles, provide excellent reinforcement per unit amount, making them a highly promising filler for resin molded articles.

[0004] Patent Document 1 discloses a resin composition comprising polyamide, elastomer and cellulose, wherein at least a portion of the elastomer has acidic functional groups, the polyamide undergoes phase separation from the elastomer, and more than 50% by mass of the cellulose is present in the polyamide phase.

[0005] Patent Document 2 discloses a resin composition comprising one or more elastomers selected from the group consisting of polyamides, aromatic vinyl compounds-conjugated diene compounds block copolymers and their derivatives, and cellulose, wherein the polyamides undergo phase separation from the elastomers, and more than 50% by mass of the cellulose is present in the polyamide phase.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2020-029488

[0009] Patent Document 2: Japanese Patent Application Publication No. 2022-007985 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] In resin molded articles, for example, resin molded articles based on styrene-based elastomers exhibit good rubber elasticity and show great promise in terms of excellent weather resistance and chemical resistance. If cellulose nanofibers can be incorporated into styrene-based elastomers, in addition to the aforementioned properties inherent in styrene-based elastomers, good tensile strength, tensile modulus of elasticity, and tensile elongation at break can also be imparted. However, styrene-based elastomers are inherently hydrophobic, while cellulose nanofibers are inherently hydrophilic due to the presence of hydroxyl groups, thus exhibiting a tendency to be difficult to mix. If the styrene-based elastomer and cellulose nanofibers are poorly mixed in the resin composition, the molded article formed from the resin composition will not exhibit the desired physical properties. Furthermore, when external force is applied to the molded article, voids are generated between the styrene-based elastomer and cellulose nanofibers, causing the molded article to whiten. On the other hand, if meticulous melt mixing of the styrene-based elastomer and cellulose nanofibers is performed to achieve good mixing, thermal degradation (e.g., discoloration) of the cellulose nanofibers may occur. The techniques described in Patent Documents 1 and 2 allow styrene-based elastomers to coexist when cellulose is dispersed in polyamide, but they do not address resin molded articles with styrene-based elastomers as the main component, and therefore do not address the aforementioned problems of the combination of styrene-based elastomers and cellulose nanofibers.

[0012] One objective of the present invention is to solve the above-mentioned problems by providing a resin composition and a method for manufacturing the same, as well as a molded body formed from the resin composition, wherein the resin composition can form a molded body that exhibits the advantageous properties inherent in styrene-based elastomers (good rubber elasticity, weather resistance, chemical resistance, etc.), and also has excellent tensile strength, tensile modulus of elasticity and / or tensile elongation at break, and thus has fewer defects such as whitening and coloring.

[0013] Furthermore, for resin molded articles containing fillers to exhibit the desired properties, it is sometimes important that the fillers be well dispersed in the resin. However, cellulose is generally hydrophilic due to its hydroxyl groups, therefore the use of styrene-based elastomers as additives for ensuring good dispersion of cellulose in the polymer has been proposed.

[0014] Styrene-based elastomers are soft and possess excellent weather resistance and chemical resistance, making molded articles using styrene-based elastomers as the main polymer component desirable. However, the applications of resin molded articles using styrene-based elastomers as the main polymer component in the prior art are limited. Styrene-based elastomers typically exhibit tackiness (initial adhesion). Therefore, it is difficult to melt-mold styrene-based elastomers individually, and styrene-based elastomer molded articles tend to adhere to each other, resulting in problems with processability and handling. The technology described in Patent Document 2 achieves the opposite properties of high toughness and low thermal expansion simultaneously by using the aforementioned elastomer in a resin composition containing polyamide and cellulose, but it does not provide molded articles using styrene-based elastomers as the main polymer component.

[0015] Therefore, another objective of the present invention is to solve the above-mentioned problems by providing a resin composition and a method for manufacturing the same, as well as a resin molded body formed from the resin composition, wherein the resin composition is capable of forming a resin molded body that exhibits the excellent properties inherent in styrene-based elastomers (especially good rubber elasticity, weather resistance, chemical resistance, etc.) and also has excellent processability and operability.

[0016] Methods for solving problems

[0017] This disclosure includes the following items.

[0018] [Project 1]

[0019] A resin composition comprising a thermoplastic elastomer and cellulose nanofibers, wherein, The aforementioned thermoplastic elastomers include acid-modified styrene-based elastomers and styrene-based elastomers. In the above resin composition, the amount of the above thermoplastic elastomer is 60% by mass or more in 100% by mass.

[0020] [Project 2]

[0021] A resin composition comprising a thermoplastic elastomer and cellulose nanofibers, wherein, The ratio of the number-average fiber length L to the number-average fiber diameter D of the cellulose nanofibers in the above resin composition, i.e., the number-average length-to-width ratio, is more than 2 and less than 26. In the above resin composition, the amount of the above thermoplastic elastomer is 60% by mass or more in 100% by mass.

[0022] [Project 3]

[0023] A resin composition comprising a thermoplastic elastomer and cellulose nanofibers, wherein, When tetrahydrofuran (THF) was used to separate the cellulose nanofibers from the above resin composition, the weight gain of the cellulose nanofibers was 190% to 600%. In the above resin composition, the amount of the above thermoplastic elastomer is 60% by mass or more in 100% by mass.

[0024] [Project 4]

[0025] The resin composition according to any one of items 1 to 3, wherein the resin composition comprises an acid-modified styrene elastomer and a styrene elastomer as the thermoplastic elastomer. In the above resin composition, the total amount of the above acid-modified styrene elastomer and the above styrene elastomer is 60% by mass or more in 100% by mass.

[0026] [Project 5]

[0027] The resin composition according to any one of items 1 to 4, wherein the resin composition comprises an acid-modified styrene elastomer and a styrene elastomer as the thermoplastic elastomer. The acid-modified styrene elastomers described above are compatible with the styrene elastomers described above.

[0028] [Project 6]

[0029] The resin composition according to any one of items 1 to 5, wherein the resin composition comprises an acid-modified styrene elastomer and a styrene elastomer as the thermoplastic elastomer. The amount of the acid-modified styrene elastomer is 0.5 to 50 parts by mass relative to 100 parts by mass of the styrene elastomer mentioned above.

[0030] [Project 7]

[0031] 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. The amount of the styrene-based elastomer is 0.5 to 250 parts by mass relative to 1 part by mass of the cellulose nanofibers mentioned above.

[0032] [Project 8]

[0033] 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. The amount of the acid-modified styrene elastomer is 0.5 to 45 parts by mass relative to 1 part by mass of the cellulose nanofibers mentioned above.

[0034] [Project 9]

[0035] 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. In the above resin composition, the amount of the above acid-modified styrene elastomer is 0.5% to 50% by mass in 100% by mass.

[0036] [Project 10]

[0037] 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. In the above resin composition, the amount of the above styrene-based elastomer is 10% to 98.8% by mass in 100% by mass.

[0038] [Project 11]

[0039] The resin composition according to any one of items 1 to 10 comprises 0.1% to 20% by mass of the above-mentioned cellulose nanofibers.

[0040] [Project 12]

[0041] 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. The acid modification rate of the above-mentioned acid-modified styrene elastomers is 0.2% to 2.5% by mass.

[0042] [Project 13]

[0043] 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. The styrene-based elastomers mentioned above are unmodified.

[0044] [Project 14]

[0045] The resin composition according to any one of items 1 to 13, wherein the resin composition comprises an acid-modified styrene-based elastomer as the thermoplastic elastomer. The aforementioned acid-modified styrene elastomer is an acid-modified styrene elastomer that is a block copolymer of aromatic vinyl compounds and conjugated diene compounds or their hydrogenated derivatives.

[0046] [Project 15]

[0047] The resin composition according to any one of items 1 to 14, wherein the resin composition comprises a styrene-based elastomer as the thermoplastic elastomer. The aforementioned styrene-based elastomers are aromatic vinyl compound-conjugated diene compound block copolymers or their hydrogenated derivatives.

[0048] [Project 16]

[0049] The resin composition according to any one of items 1 to 15, wherein the resin composition comprises a styrene-based elastomer as the thermoplastic elastomer. The melt flow rate of the above-mentioned styrene-based elastomer at 230°C and 2.16 kg is less than 20 g / 10 min.

[0050] [Project 17]

[0051] The resin composition according to any one of items 1 to 16, wherein the resin composition comprises an acid-modified styrene-based elastomer as the thermoplastic elastomer. The styrene unit ratio of the above acid-modified styrene elastomers is 10% to 45% by mass.

[0052] [Project 18]

[0053] 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. The styrene unit content of the above-mentioned styrene-based elastomers is 10% to 45% by mass.

[0054] [Project 19]

[0055] The resin composition according to any one of items 1 to 18, wherein the resin composition comprises an acid-modified styrene elastomer and a styrene elastomer as the thermoplastic elastomer. The ratio of styrene unit proportion in the above-mentioned styrene-based elastomer to the styrene unit proportion in the above-mentioned acid-modified styrene-based elastomer (styrene proportion in styrene-based elastomer / styrene proportion in acid-modified styrene-based elastomer) is 0.3 to 2.5.

[0056] [Project 20]

[0057] The resin composition according to any one of items 1 to 19, wherein the resin composition comprises an acid-modified styrene elastomer and a styrene elastomer as the thermoplastic elastomer. The number-average molecular weight of the above-mentioned acid-modified styrene-based elastomers is 10,000 to 500,000.

[0058] [Project 21]

[0059] 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. In the above-mentioned acid-modified styrene-based elastomers, the ratio of styrene unit proportion to acid modification rate (styrene unit proportion / acid modification rate) is 5 to 90.

[0060] [Project 22]

[0061] 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. Relative to 100% by mass of the above cellulose nanofibers, the amount of acid-modified groups in the above acid-modified styrene elastomer is 0.2% to 5.0% by mass.

[0062] [Project 23]

[0063] The resin composition according to any one of items 1 to 22, wherein the number-average fiber diameter of the cellulose nanofibers is 2 nm to 1000 nm.

[0064] [Project 24]

[0065] The resin composition according to any one of items 1 to 23, wherein the thermal decomposition initiation temperature of the cellulose nanofibers is above 250°C.

[0066] [Project 25]

[0067] The resin composition according to any one of items 1 to 24, wherein the specific surface area of ​​the cellulose nanofibers is 10 m². 2 / g~200m 2 / g.

[0068] [Project 26]

[0069] The resin composition according to any one of items 1 to 25 further comprises a polymer containing polyoxyethylene units.

[0070] [Project 27]

[0071] The resin composition according to any one of items 1 to 26 further comprises a liquid polymer.

[0072] [Project 28]

[0073] A method for manufacturing the resin composition described in any one of items 1 to 27, wherein, The above resin composition includes an acid-modified styrene elastomer and a styrene elastomer as the above thermoplastic elastomer. The above method includes the following steps: heating and kneading a mixture comprising the above-mentioned acid-modified styrene elastomer, the above-mentioned styrene elastomer and the above-mentioned cellulose nanofibers.

[0074] [Project 29]

[0075] According to the method described in Project 28, the weight increase rate of the cellulose nanofibers after heating and mixing is 190% to 600% relative to the cellulose nanofibers before heating and mixing.

[0076] [Project 30]

[0077] A resin molded body is formed by molding the resin composition described in any one of items 1 to 27.

[0078] [Project 31]

[0079] The resin molded article according to item 30 is a shaped extruded molded article.

[0080] [Project 32]

[0081] A method for manufacturing a profiled extruded article, wherein the method includes a step of profiled extrusion of the resin composition described in any one of items 1 to 27.

[0082] [Project 33]

[0083] A modeling material for 3D printing, comprising any one of the resin compositions described in items 1 to 27.

[0084] [Project 34]

[0085] The 3D printing modeling material described in Project 33 has the form of filaments or powder.

[0086] [Project 35]

[0087] A modeling object made by molding the resin composition described in any one of items 1 to 27 using a 3D printer.

[0088] [Project 36]

[0089] An object formed by using a 3D printer to shape the 3D printing modeling material described in item 33 or 34.

[0090] [Project 37]

[0091] A method for manufacturing a shaped object, wherein the method includes a step of molding the resin composition described in any one of items 1 to 27 using a 3D printer.

[0092] [Project 38]

[0093] A method for manufacturing a model, wherein the method includes a step of using a 3D printer to shape the 3D printing modeling material described in item 33 or 34.

[0094] [Project 39]

[0095] A resin composition comprising a styrene-based elastomer and a viscosity inhibitor containing cellulose nanofibers.

[0096] The effects of the invention

[0097] According to one aspect of the present invention, a resin composition and a method for manufacturing the same, as well as a molded body formed from the resin composition, are provided, wherein the resin composition is capable of forming a resin molded body that exhibits the advantageous properties inherent in styrene-based elastomers (good rubber elasticity, weather resistance, chemical resistance, etc.), and also has excellent tensile strength, tensile modulus of elasticity, and / or tensile elongation at break, and thus has fewer defects such as whitening and coloring.

[0098] According to another aspect of the present invention, a resin composition and a method for manufacturing the same, as well as a resin molded body formed from the resin composition, are provided, wherein the resin composition is capable of forming a resin molded body exhibiting the excellent properties inherent in styrene-based elastomers (especially good rubber elasticity, weather resistance, chemical resistance, etc.) and also exhibiting excellent processability and operability. Detailed Implementation

[0099] Hereinafter, exemplary embodiments of the present invention (hereinafter also referred to as these embodiments) will be described, but the present invention is not limited to these embodiments and various modifications can be made within the scope of its spirit.

[0100] Resin Compositions

[0101] 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. The thermoplastic elastomer in one aspect comprises a styrene-based elastomer, in another aspect it comprises an acid-modified styrene-based elastomer, in yet another aspect it comprises both a styrene-based elastomer and an acid-modified styrene-based elastomer, and in yet another aspect it comprises both a styrene-based elastomer and an acid-modified styrene-based elastomer.

[0102] In one embodiment, the ratio of the number-average fiber length L to the number-average fiber diameter D of the cellulose nanofibers in the resin composition, i.e., the number-average length-to-width ratio, is 2 or more and 26 or less.

[0103] In one embodiment, the weight gain of cellulose nanofibers when using tetrahydrofuran (THF) to separate cellulose nanofibers from a resin composition is 190% to 600%.

[0104] One aspect of the present invention provides a resin composition comprising an acid-modified styrene-based elastomer, a styrene-based elastomer, and cellulose nanofibers. In one embodiment of the resin composition, the acid-modified styrene-based elastomer and the styrene-based elastomer are compatible without phase separation and are a continuous phase. In one embodiment, the combined 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. The styrene-based elastomer portion in the resin composition helps to exhibit the inherently good properties of styrene-based elastomers. On the other hand, the acid-modified styrene-based elastomer portion in the resin composition, through good affinity with both the styrene-based elastomer and the cellulose nanofibers, is situated between the styrene-based elastomer and the cellulose nanofibers, which helps to reduce adverse conditions caused by their lack of affinity (e.g., void formation due to delamination between them).

[0105] In one type of resin composition, it was found that the presence of cellulose nanofibers and acid-modified styrene-based elastomers reduced fuzziness during extrusion molding. This resulted in molded articles exhibiting good surface smoothness. The reason for the excellent reduction in fuzziness caused by cellulose nanofibers and acid-modified styrene-based elastomers is not yet clear, but the cellulose nanofibers and acid-modified styrene-based elastomers are bonded through a reaction, which modifies the surface of the styrene-based elastomer during molding, potentially resulting in a smoothing effect. Furthermore, the addition of cellulose nanofibers to the styrene-based elastomers can also help reduce molding shrinkage and improve the tensile strength, tensile modulus of elasticity, elongation at break, and / or hardness of the molded articles. It was also found that in one type of resin composition, the presence of acid-modified styrene-based elastomers in addition to cellulose nanofibers further improved the tensile strength, tensile modulus of elasticity, elongation at break, and / or hardness of the molded articles, and reduced undesirable conditions such as whitening and discoloration. Although not bound by theory, it is believed that the reaction between the hydroxyl groups of cellulose nanofibers and the acid-modified groups of acid-modified styrene elastomers strengthens their interface, thereby reducing the likelihood of delamination between the styrene elastomer, cellulose nanofibers, and acid-modified styrene elastomer when external forces are applied to the molded body, and also reducing the likelihood of discoloration caused by the thermal degradation of cellulose nanofibers. Therefore, it is believed that the property improvement effect brought by cellulose nanofibers is well utilized, and the formation of voids in the molded body caused by delamination is suppressed, reducing whitening and thus also suppressing the discoloration of cellulose nanofibers. One type of resin composition uses styrene elastomers with excellent rubber elasticity, weather resistance, and chemical resistance, but also exhibits excellent processability and handling properties, effectively utilizing the property improvement effect brought by cellulose nanofibers, resulting in fewer adverse conditions such as whitening and discoloration. Therefore, it is suitable, for example, as a substitute for thermoplastic polyurethane elastomers (TPU).

[0106] One aspect of the present invention also provides a resin composition comprising a styrene-based elastomer and a tackiness inhibitor containing cellulose nanofibers. Styrene-based elastomers inherently possess good rubber elasticity, weather resistance, and chemical resistance, but due to their tackiness, they tend to be difficult to mold and process. For example, tacky molding materials are difficult to detach from the mold during molding; if a strong force is applied to peel the molded body from the mold, deformation and breakage will occur, making it difficult to obtain a good molded body. Furthermore, when storing tacky granules, briquettes, injection molded bodies, films, sheets, filaments, etc., the contact portions of the molded bodies stick together, creating operational difficulties in all processes. In one aspect of the resin composition, it has been found that the presence of cellulose nanofibers suppresses tackiness, thereby facilitating molding and processing of the molded body. In one aspect, the cellulose nanofibers can function as a tackiness inhibitor either alone or in collaboration with other components in the resin composition. The reasons for the excellent viscosity-reducing effect of cellulose nanofibers in styrene-based elastomers are not yet clear. However, due to the contribution of the fine fibrous structure of cellulose nanofibers, they are easier to physically entangle with styrene-based elastomers compared to other fillers (such as silica particles, glass fibers, carbon fibers, etc.), thus potentially exhibiting a good viscosity-reducing effect. Cellulose nanofibers are softer than materials such as silica particles, glass fibers, and carbon fibers, which is advantageous in that they do not impair the inherent rubber elasticity of styrene-based elastomers. Furthermore, the addition of cellulose nanofibers to styrene-based elastomers can also help reduce shrinkage during molding and improve the tensile strength, tensile modulus of elasticity, tensile elongation at break, and / or hardness of the molded articles. One type of resin composition, although using styrene-based elastomers, exhibits suppressed viscosity and excellent processability and handling properties, making it useful as a soft resin molded article, and suitable, for example, as a substitute for thermoplastic polyurethane elastomers (TPU).

[0107] One type of resin composition exhibits a tack strength (sometimes referred to as tack strength hereinafter) of 10.0 gf / mm², determined by a probe tack test under the conditions of 23°C, a load of 600 gf, a pressing time of 60 seconds, and a peel speed of 600 mm / min. 2 The above-mentioned viscous strength can be 9.0 gf / mm in one method. 2 Below, or 7.0gf / mm 2 Below, or 5.0gf / mm 2 Below, or 3.0gf / mm 2 Below, or 2.0gf / mm 2 Below, or 1.5gf / mm 2 Below, or 1.0gf / mm 2Below. From the perspective of ease of manufacture of the resin composition, the aforementioned tack strength can be 0.001 gf / mm in one embodiment. 2 Above, or 0.01gf / mm 2 Above, or 0.1gf / mm 2 Above, or 0.3gf / mm 2 Above, or 0.5gf / mm 2 above.

[0108] Compared to the tack strength of a resin composition with the same composition except for the absence of cellulose nanofibers (100%), the tack strength of a resin composition in 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. From the perspective of suppressing tackiness, the lower the above proportions, the better; however, from the perspective of ease of manufacturing the resin composition, in one embodiment, it can be 0.0001% or more, or 0.1% or more, or 1% or more, or 3% or more.

[0109] Regarding the tack strength of a resin composition of a certain manner, the ratio exemplified above is preferably shown as 100% relative to the tack strength of the styrene-based elastomer contained in the resin composition.

[0110] The components of the resin composition will now be described. It should be noted that, in this embodiment, the amounts of each component recorded as values ​​in the resin composition can be considered as the amounts of each component in the resin composition.

[0111] Cellulose nanofibers

[0112] Cellulose nanofibers are fibers obtained by micronizing cellulose fiber raw materials through processes such as defiberization. Natural cellulose and regenerated cellulose can be used as cellulose fiber raw materials. Natural cellulose can be wood pulp from wood species (broadleaf or coniferous trees), non-wood pulp from non-wood species (cotton, bamboo, hemp, bagasse, kenaf, cotton linters, sisal, rice straw, etc.), cellulose fiber aggregates produced by animals (e.g., tunicates), algae, or microorganisms (e.g., acetic acid bacteria). Regenerated cellulose can be regenerated cellulose fibers (viscose, cuprammonium cellulose, Tencel, etc.), cellulose derivative fibers, or ultrafine yarns of regenerated cellulose or cellulose derivatives obtained by electrospinning. Cellulose fiber raw materials that provide cellulose nanofibers with a napped surface are sometimes advantageous in terms of viscosity-inhibiting effects. Cotton linters are an example of a preferred cellulose fiber raw material in this regard.

[0113] In one approach, defiberization is a dry or wet mechanical process, preferably a wet process that mechanically processes the pulp obtained by dispersing cellulose fiber raw materials in a liquid medium. Defiberization can be performed using a single device or multiple devices separately. The device used for defiberization is not particularly limited, and examples include high-speed rotary mills, colloid mills, high-pressure mills, roller mills, ultrasonic mills, high-pressure or ultra-high-pressure homogenizers, fine grinding mills, pulpers, PFI mills, kneaders, dispersers, high-speed defiberizers, grinders (mortar-type pulverizers), ball mills, vibratory mills, bead mills, conical fine grinding mills, disc fine grinding mills, single-screw, twin-screw or multi-screw mixers / extruders, etc.

[0114] Cellulose fiber raw materials can be pre-treated before defiberization. Pre-treatment can be used to adjust fiber diameter, fiber length, degree of fibrillation, etc., or to adjust the content of components other than cellulose (such as acid-insoluble components like lignin, alkali-soluble polysaccharides like hemicellulose), or to adjust molecular weight, crystallinity, etc.

[0115] In one approach, pretreatment can be selected from one or more of chemical treatment, pulverization, milling, and classification. Chemical treatment is treatment using chemicals, such as cooking, bleaching, purification, hydrolysis, enzymatic treatment, regenerated cellulose, and chemical modification. Pulverization is a dry pulverization process of cellulose fiber raw materials. Milling is a process of pulverizing a pulp obtained by dispersing cellulose fiber raw materials in a liquid medium, distinguishing it from the above-mentioned pulverization in that it is a wet process. Classification is a separation operation used to make the fiber length of the cellulose fiber raw materials uniform, and can be dry classification or wet classification.

[0116] Examples of liquid media include water and / or other media (e.g., organic solvents, inorganic acids, bases and / or ionic liquids), and may include one or more media.

[0117] Examples of commonly used organic solvents include alcohols (e.g., methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, ethylene glycol, diethylene glycol, glycerol, 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) of one or more. In a typical configuration, the liquid medium in the slurry is essentially only water.

[0118] In one embodiment, from the perspective of effectively exhibiting the property-enhancing effect brought about by cellulose nanofibers, 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 perspective of effectively dispersing the cellulose nanofibers in the resin composition, it 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.

[0119] In one embodiment, from the perspective of obtaining the improved physical properties brought about by cellulose nanofibers, the number-average fiber diameter D of the cellulose nanofibers is preferably 2 nm to 1000 nm. More preferably, the number-average fiber diameter of the cellulose nanofibers is 4 nm or more, or 5 nm or more, or 10 nm or more, or 15 nm or more, or 20 nm or more; even more preferably, it is 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.

[0120] From the perspective of effectively improving the mechanical properties of rubber composites containing cellulose nanofibers by utilizing 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 perspective of processability, it is preferably 5000 or less, or 3000 or less, or 2000 or less, or 1000 or less.

[0121] In this disclosure, the fiber length, fiber diameter, and L / D ratio of cellulose nanofibers are determined using a scanning electron microscope (SEM) according to the following steps. An aqueous dispersion of cellulose nanofibers is diluted to 0.001%–0.1% by mass with tert-butanol, and dispersed using a high-shear homogenizer (e.g., IKA-manufactured, trade name "ULTRA-TURRAX T18") under the following conditions: 15,000 rpm × 3 minutes. The dispersion is then cast onto an osmium-deposited silicon substrate. The air-dried material is used as the test sample, and the measurements are obtained using a high-resolution scanning electron microscope (SEM). Specifically, in an observation field adjusted to allow observation of at least 100 cellulose nanofibers, the length (L) and diameter (D) of 100 randomly selected cellulose nanofibers are measured, and the ratio (L / D) is calculated. Then, the number mean values ​​of each are used as the number-average fiber diameter L and the number-average fiber diameter D, and the ratio (L / D) is calculated.

[0122] In one embodiment, the ratio of the number-average fiber length L to the number-average fiber diameter D of the cellulose nanofibers in the resin composition, i.e., the number-average aspect ratio, is 2 or more and 26 or less. The upper limit of this aspect ratio is not particularly limited, but from a processability perspective, it is preferably 25 or less. The lower limit of this aspect ratio is not particularly limited, but it 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 one of the [Examples] of this disclosure.

[0123] Cellulose crystals are known to be of types I, II, III, and IV, among which types I and II are commonly used. While types III and IV can be obtained on a laboratory scale, they are not commonly used on an industrial scale. Regarding the cellulose nanofibers of this disclosure, from the perspective of high structural mobility and obtaining molded articles with lower coefficients of linear expansion and superior strength and elongation under tensile and flexural deformation by dispersing the cellulose nanofibers in rubber, cellulose nanofibers containing type I or type II cellulose crystals are preferred, and cellulose nanofibers containing type I cellulose crystals with a crystallinity of 55% or higher are more preferred.

[0124] The crystallinity of cellulose nanofibers is preferably 55% or higher. Higher crystallinity results in higher mechanical properties (strength, dimensional stability) of cellulose itself, thus leading to a tendency for the rubber composite to exhibit high strength and dimensional stability when cellulose nanofibers are dispersed in rubber. A more preferred lower limit for crystallinity is 60%, further preferably 70%, and most preferably 80%. While there is no particular upper limit for the crystallinity of cellulose nanofibers, a higher limit is preferred; from a production perspective, a preferred upper limit is 99%.

[0125] The crystallinity referred to here, when the cellulose nanofibers are cellulose type I crystals (derived from natural cellulose), is determined by the following formula using the Segal method, based on the diffraction pattern (2θ / deg. is 10-30) when the sample is measured by wide-angle X-ray diffraction.

[0126] Crystallinity (%) = [I (200) -I (amorphous) ] / I (200) ×100

[0127] I (200) Intensity of diffraction peaks on the 200 plane (2θ = 22.5°) in type I cellulose crystals.

[0128] I (amorphous) The peak intensity of the amorphous halo in type I cellulose crystals is the peak intensity at an angle 4.5° lower than the diffraction angle of the 200 plane (2θ = 18.0°).

[0129] In addition, when the cellulose is cellulose type II crystal (from regenerated cellulose), the crystallinity is determined by the absolute peak intensity h0 at 2θ = 12.6° of the (110) plane peak belonging to cellulose type II crystal in wide-angle X-ray diffraction and the peak intensity h1 of the baseline at the plane interval (the line connecting 2θ = 8° and 15°) by the following formula.

[0130] Crystallinity (%) = (h0 - h1) / h0 × 100

[0131] In addition, the degree of polymerization of 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, preferably 3500 or less, more preferably 3300 or less, more preferably 3200 or less, more preferably 3100 or less, more preferably 3000 or less.

[0132] From the perspectives of processability and mechanical properties, it is preferable that the degree of polymerization of cellulose nanofibers is within the aforementioned range. From the perspective of processability, it is preferable that the degree of polymerization is not too high, and from the perspective of mechanical properties, it is desirable that the degree of polymerization is not too low.

[0133] The degree of polymerization of cellulose nanofibers refers to the average degree of polymerization determined by the reduction ratio viscosity method of copper ethylenediamine solution as described in the confirmation test (3) of the "Explanation of the Fifteenth Revision of the Japanese Pharmacopoeia (published by Hirokawa Shoten)".

[0134] In one embodiment, the weight-average molecular weight (Mw) of the cellulose nanofibers is 100,000 or more, more preferably 200,000 or more. The ratio of weight-average molecular weight to number-average molecular weight (Mn) (Mw / Mn) is 6 or less, preferably 5.6 or less, or 5.4 or less. A higher weight-average molecular weight means fewer terminal groups in the cellulose molecules. Furthermore, the ratio of weight-average molecular weight to number-average molecular weight (Mw / Mn) represents the width of the molecular weight distribution; therefore, a smaller Mw / Mn means fewer terminal groups in the cellulose molecules. Since the terminals of cellulose molecules become the starting point for thermal decomposition, cellulose nanofibers with particularly high heat resistance and resin compositions containing cellulose nanofibers can be obtained when not only the weight-average molecular weight of the cellulose nanofibers is high, but also the width of the molecular weight distribution is narrow. From the perspective of the ease of obtaining cellulose raw materials, the weight-average molecular weight (Mw) of the cellulose nanofibers can be, for example, 600,000 or less, 500,000 or less, or 400,000 or less. From the perspective of ease of obtaining cellulose fiber raw materials, the number-average molecular weight (Mn) of cellulose nanofibers can 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 perspective of ease of manufacturing cellulose nanofibers, the ratio of weight-average molecular weight to number-average molecular weight (Mn) (Mw / Mn) can be, for example, 1.5 or more, or 1.7 or more, or 2 or more. Mw can be controlled to the above range by selecting cellulose raw materials with a Mw appropriate to the target, and by appropriately performing physical and / or chemical treatment on the cellulose raw materials within a suitable range. Mw / Mn can also be controlled to the above range by selecting cellulose raw materials with a Mw / Mn appropriate to the target, and by appropriately performing physical and / or chemical treatment on the cellulose raw materials within a suitable range. The Mw and Mw / Mn of the cellulose raw materials can each be within the above range in one manner.

[0135] The weight-average molecular weight and number-average molecular weight of cellulose nanofibers mentioned here refer to the values ​​obtained by gel permeation chromatography using N,N-dimethylacetamide as a solvent after dissolving cellulose nanofibers in N,N-dimethylacetamide with added lithium chloride.

[0136] Cellulose nanofibers may contain alkali-soluble polysaccharides, including not only hemicellulose but also β-cellulose and γ-cellulose. Alkali-soluble polysaccharides, as understood by those skilled in the art, refer to the alkali-soluble components obtained from whole cellulose (i.e., the components obtained by removing α-cellulose from whole cellulose) through solvent extraction and chlorination of plants (e.g., wood). Alkali-soluble polysaccharides are hydroxyl-containing polysaccharides, which have poor heat resistance and may lead to decomposition upon heating, yellowing during thermal aging, and reduced strength of cellulose nanofibers. Therefore, it is preferable that cellulose nanofibers contain a low content of alkali-soluble polysaccharides.

[0137] In one embodiment, from the perspective of obtaining good dispersibility of cellulose nanofibers, the average content of alkali-soluble polysaccharides in the cellulose nanofibers is preferably 20% by mass or less, or 18% by mass or less, or 15% by mass or less, or 12% by mass or less relative to 100% by mass of cellulose nanofibers. From the perspective of ease of manufacturing cellulose nanofibers, the above content can be 1% by mass or more, or 2% by mass or more, or 3% by mass or more.

[0138] The average content of alkali-soluble polysaccharides can be determined using a method described in non-patent literature (Handbook of Wood Science Experiments, edited by the Japan Wood Science Society, pp. 92-97, 2000), by subtracting the α-cellulose content from the total cellulose content (Wise method). Furthermore, this method is understood in the art as a method for determining hemicellulose content. The alkali-soluble polysaccharide content is calculated three times for each sample, and the mean of the calculated alkali-soluble polysaccharide contents is taken as the average alkali-soluble polysaccharide content.

[0139] In one approach, to avoid a decrease in the heat resistance of cellulose nanofibers and the associated discoloration, 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 perspective of ease of manufacturing cellulose nanofibers, the above content can be 0.1% by mass or more, or 0.2% by mass or more, or 0.3% by mass or more.

[0140] The average content of acid-insoluble components was determined using the Claessen method described in non-patent literature (Handbook of Wood Science Experiments, edited by the Japan Wood Science Society, pp. 92-97, 2000). It should be noted that this method is understood in the art as a method for determining lignin content. After dissolving cellulose and hemicellulose in sulfuric acid solution, the sample was filtered through glass fiber filter paper, and the residue represented the acid-insoluble components. The content of the acid-insoluble components was calculated from their weight. Then, the acid-insoluble component content was measured three times for each sample, and the average of these measurements was taken as the average content of the acid-insoluble components.

[0141] [Chemical modification]

[0142] Cellulose nanofibers can be chemically modified cellulose nanofibers (also known as chemically modified cellulose nanofibers). Examples of chemically modified cellulose nanofibers include inorganic esters such as nitrates, sulfates, phosphates, silicates, and borates; organic esters such as acetylation and propionylation; ethers such as methyl ethers, hydroxyethyl ethers, hydroxypropyl ethers, hydroxybutyl ethers, carboxymethyl ethers, and cyanoethyl ethers; and TEMPO oxides formed by oxidizing the primary hydroxyl groups of cellulose. Chemically modified cellulose nanofibers can contain one or more modifying groups.

[0143] In a preferred embodiment, the chemical modification is acylation using an esterifying agent, particularly acetylation. As esterifying agents, acyl halides, acid anhydrides, vinyl carboxylate, and carboxylic acids are preferred. From the perspective of reaction efficiency, at least one of the following groups is particularly preferred: acetic anhydride, propionic anhydride, butyric anhydride, vinyl acetate, vinyl propionate, butyric anhydride, and acetic acid, with acetic anhydride and vinyl acetate being preferred. Cellulose nanofibers can be chemically modified using a modifying agent at, for example, the stage of cellulose fiber raw material preparation, during or after defibrillation, or during or after the preparation of a slurry as a dispersion, or during or after a drying process.

[0144] [Degree of acyl substitution (DS)]

[0145] When cellulose nanofibers are chemically modified (e.g., through hydrophobication such as acylation), they tend to exhibit good dispersibility in rubber. On the other hand, when combined with a dispersant, even if the cellulose nanofibers are unsubstituted or have a low degree of substitution, they readily exhibit good dispersibility in rubber. When the cellulose nanofibers are esterified cellulose nanofibers, from the perspective of obtaining esterified cellulose nanofibers with high thermal decomposition initiation temperatures, 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. From the perspective of obtaining esterified cellulose nanofibers that possess both high tensile strength and dimensional stability derived from cellulose and high thermal decomposition initiation temperatures derived from chemical modification due to the presence of unmodified cellulose backbone in the esterified cellulose nanofibers, the 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.

[0146] The degree of acyl substitution (DS) of chemically modified cellulose nanofibers, where the modifying group is an acyl group, can be calculated based on the reflectance infrared absorption spectrum of esterified cellulose nanofibers, using the peak intensity ratio between the peaks originating from the acyl group and those originating from the cellulose backbone. The absorption band of the C=O group based on the acyl group appears at 1730 cm⁻¹. -1 The CO absorption band based on the cellulose backbone chain shows a peak at 1030 cm⁻¹. -1 Regarding the degree of substitution (DS) of esterified cellulose nanofibers, a correlation graph can be constructed between the DS obtained from solid-state NMR measurements of the esterified cellulose nanofibers (described later) and the degree of modification (IR index 1030), defined as the ratio of the peak intensity of the C=O absorption band based on the acyl group to the peak intensity of the absorption band of the CO backbone of the cellulose skeleton chain. The degree of substitution can be determined using a standard curve calculated from the correlation graph: degree of substitution DS = 4.13 × IR index (1030).

[0147] IR index (1030) = H1730 / H1030

[0148] In the formula, H1730 and H1030 are 1730 cm. -1 1030cm -1 The absorbance at the absorption band of the CO stretching vibration of the cellulose backbone chain. Here, refers to the absorbance at 1900 cm⁻¹. -1 and 1500cm -1 The line and connection 800cm -1 and 1500cm -1 The line is used as the baseline, and the absorbance at which the absorbance is 0 is set.

[0149] In the method of calculating the DS of esterified cellulose nanofibers based on solid-state NMR, the cryogenically pulverized esterified cellulose nanofibers can be analyzed. 13 The area intensity (Inf) of the signal attributable to a single carbon atom originating from a modifying group is determined by the following formula relative to the total area intensity (Inp) of the signal attributable to carbons C1 to C6 of the pyranose ring derived from cellulose appearing in the range of 50 ppm to 110 ppm.

[0150] DS = (Inf) × 6 / (Inp)

[0151] For example, when the modifying group is acetyl, a signal of 23 ppm belonging to -CH3 can be used.

[0152] Used 13 The conditions for C solid-state NMR measurements are as follows.

[0153] Device: Bruker Biospin Avance500WB

[0154] Frequency: 125.77MHz

[0155] Determination method: DD / MAS method

[0156] Waiting time: 75 seconds

[0157] NMR sample tube: 4mm Φ

[0158] Total number of times: 640 (approximately 14 hours)

[0159] MAS: 14,500Hz

[0160] Chemical shift reference: glycine (external reference: 176.03 ppm)

[0161] From the perspective of achieving the desired heat resistance and mechanical strength for applications such as automotive, the thermal decomposition initiation temperature (T0) of cellulose nanofibers... D In one embodiment, the preferred temperatures are 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. Higher thermal decomposition initiation temperatures are preferred, but from the perspective of ease of manufacturing cellulose nanofibers, temperatures can be, for example, below 320°C, or below 310°C, or below 300°C.

[0162] [Temperature at 1% weight loss (T)] 1% ), weight loss rate at 250℃ (T 250℃ )]

[0163] From the perspective of avoiding thermal degradation during melt mixing and maintaining mechanical strength, in one approach, the temperature at which 1 wt% weight of cellulose nanofibers decreases (T) is considered. 1% The preferred temperatures are above 230°C, or above 240°C, or above 250°C, or above 260°C, or above 270°C, or above 275°C, or above 280°C, or above 285°C, or above 290°C. 1% The higher the temperature, the better. From the perspective of ease of manufacturing cellulose nanofibers, for example, it can be below 330°C, or below 320°C, or below 310°C.

[0164] From the perspective of avoiding thermal degradation during melt mixing and maintaining mechanical strength, in one approach, the weight loss rate (T) of cellulose nanofibers at 250°C is... 250℃ The preferred percentages are below 15%, 12%, 10%, 8%, 6%, 5%, 4%, or 3%. 250℃The lower the value, the better. However, from the perspective of ease of manufacturing cellulose nanofibers, it can be, for example, 0.1% or more, or 0.5% or more, or 0.7% or more, or 1.0% or more.

[0165] In this disclosure, T D The values ​​were derived from a thermogravimetric (TG) analysis chart where the horizontal axis represents temperature and the vertical axis represents the percentage of weight remaining. Starting with the weight of cellulose nanofibers at 150°C (with almost all moisture removed) (weight loss of 0 wt%), the temperature at which a 1 wt% weight loss was achieved was obtained (T). 1% ) and the temperature at which a 2wt% weight loss occurs (T) 2% The straight line. The temperature at the point where this straight line intersects the horizontal line (baseline) passing through the starting point of 0 wt% weight reduction is defined as T. D .

[0166] 1% weight reduction temperature (T) 1% ) is based on the above T D The method is to continuously increase the temperature at which 1% of the weight is reduced, starting from 150°C.

[0167] Weight loss rate of cellulose nanofibers at 250°C (T 250℃ The weight loss of cellulose nanofibers after being held at 250°C under a nitrogen flow for 2 hours, as determined by TG analysis, is shown. Porous sheets of cellulose nanofibers were heated from room temperature to 150°C in a nitrogen flow at a rate of 10°C / min (100 ml / min), held at 150°C for 1 hour, and then heated from 150°C to 250°C at a rate of 10°C / min, held directly at 250°C for 2 hours. The weight W0 at the moment of reaching 250°C is taken as the starting point, and the weight after holding at 250°C for 2 hours is set as W1, calculated using the following formula.

[0168] Weight change rate at 250℃ (%): (W1-W0) / W0×100

[0169] [Porous sheet]

[0170] Various physical properties of cellulose nanofibers (crystallinity, crystal polymorphism, degree of polymerization, Mw, Mn, Mw / Mn, alkali-soluble content, average acid-insoluble content, T) D T 1% T 250℃ In measurements of (etc.), the values ​​sometimes vary significantly depending on the morphology of the sample. To ensure stable and reproducible measurements, porous sheets without deformation are used for the samples. The method for preparing porous sheets is described below.

[0171] First, a concentrated filter cake of cellulose nanofibers with a solid content of 10% by mass or more was added to tert-butanol and further dispersed using a mixer or similar device until no agglomerates remained. The concentration was adjusted to 0.5% by mass for a solid content of 0.5g of cellulose nanofibers. 100g of the resulting tert-butanol dispersion was filtered onto filter paper. Instead of peeling the filter paper off, the filter cake was sandwiched between two larger sheets of filter paper, and the edges of the larger sheets were pressed down with a weight while drying in an oven at 150°C for 5 minutes. Then, the filter paper was peeled off, yielding a porous sheet with minimal deformation. The air permeability resistance R of this sheet was measured to be within 10g / m³. 2 Plates with a substrate weight of less than 100 sec / 100 ml are used as porous plates for the determination of samples.

[0172] The air permeability resistance R was determined as follows: the basis weight W (g / m³) of the porous sheet sample that had been left to stand for one day at 23℃ and 50%RH was measured. 2 Afterwards, the air permeability resistance R (sec / 100ml) is measured using a Wangyan-type air permeability resistance tester (e.g., Asahi Seiko Co., Ltd., model EG01). Then, the air permeability resistance per 10g / m³ is calculated using the following formula. 2 The value of the basis weight.

[0173] per 10g / m 2 Air permeability resistance per unit weight (sec / 100ml) = R / W × 10

[0174] [Specific surface area]

[0175] From the perspective of achieving a good color tone in the resin composition by highly miniaturizing cellulose nanofibers and effectively reducing the viscosity of styrene-based elastomers, the specific surface area of ​​the cellulose nanofibers is preferably 10 m². 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 From the perspective of ease of manufacturing and processing cellulose nanofibers, 200m or more is preferred. 2 / g or less, or 170m 2 / g or less, or 160m 2 / g or less. Regarding specific surface area, approximately 0.2g of sample was dried at 120°C under vacuum for 5 hours using a specific surface area and pore size distribution measuring device (e.g., Nova-4200e, Quantachrome Instruments). The adsorption amount of nitrogen at the boiling point of liquid nitrogen was measured at 5 points (multi-point method) within a relative vapor pressure (P / P0) range of 0.05 to 0.2. The BET specific surface area (m²) was calculated using the device's program. 2 / g), and thus the determination is performed.

[0176] Alternatively, from the perspective of achieving good transparency of the resin composition by highly miniaturizing the cellulose nanofibers, the specific surface area of ​​the cellulose nanofibers is preferably 10 m². 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 From the perspective of ease of manufacturing and processing cellulose nanofibers, 200m or more is preferred. 2 / g or less, or 170m 2 / g or less, or 160m 2 / g or less. The above range is particularly preferred in the use of adhesive inhibitors comprising cellulose nanofibers. Cellulose nanofibers with a large specific surface area are sometimes advantageous in terms of adhesive inhibition effect. From this perspective, a specific surface area of ​​10m² is preferred. 2 / g or more, or 20m 2 / g or more, or 30m 2 / g or more.

[0177] Various physical properties of cellulose nanofibers contained in resin compositions, etc. (number-average fiber length, number-average fiber diameter, L / D ratio, crystallinity, crystal polymorphism, degree of polymerization, Mw, Mn, Mw / Mn, alkali-soluble component content, average acid-insoluble component content, T) D T 1% T 250℃ , DS, specific surface area, etc. are analyzed using the following methods.

[0178] The polymer component is dissolved in an organic or inorganic solvent capable of dissolving polymer components contained in resin compositions, etc., to separate cellulose nanofibers. After thorough washing with the aforementioned solvent, the solvent is replaced with tert-butanol. Then, the tert-butanol slurry of cellulose nanofibers is analyzed using the same assay method as described above, and various physical properties of the cellulose nanofibers in the resin composition are calculated.

[0179] From the perspective of the interfacial strength between the resin and cellulose nanofibers, the weight gain rate of the cellulose nanofibers when separating them 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 perspective of suppressing short fiber formation during compounding, it is preferably 600% or less, or 550% or less, or 500% or less. The weight gain rate is a value measured by the method described in one of the [Examples] of this disclosure.

[0180] In one embodiment, cellulose nanofibers can be provided in the form of a slurry containing a liquid medium, or in the form of dried particles, films, blocks, etc. Examples of liquid media include water and / or organic solvents with boiling points, and one or more media may be included. In the slurry form, the liquid medium content is 50% by mass or more, and in the dried form, the liquid medium content is less than 50% by mass. The liquid medium content is measured using an infrared heating moisture meter (e.g., manufactured by A&D Corporation, trade name "MX-50") after heating at 180°C. In the embodiment using a viscosity inhibitor containing cellulose nanofibers, from the perspective of obtaining a better viscosity-inhibiting effect, the form of cellulose nanofibers mixed with a styrene-based elastomer is preferably a dried form.

[0181] From the perspective of effectively obtaining the advantages brought by cellulose nanofibers, 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 perspective of the impact resistance of the resin composition, it is preferably 20% by mass or less, or 15% by mass or less, or 10% by mass or less. In the use of a viscosity inhibitor containing cellulose nanofibers, from the perspective of effectively exhibiting viscosity-inhibiting effects, the amount of cellulose nanofibers is particularly preferred to be 0.5% by mass or more, or 0.7% by mass or more, or 1.0% by mass or more.

[0182] <Thermoplastic Elastomers>

[0183] Thermoplastic elastomers include, in one embodiment, a styrene-based elastomer, an acid-modified styrene-based elastomer, a combination of a styrene-based elastomer and an acid-modified styrene-based elastomer, and a combination of a styrene-based elastomer and an acid-modified styrene-based elastomer. In this disclosure, an elastomer in one embodiment refers to a substance that is elastic at room temperature (23°C) (specifically, a natural or synthetic polymer). Furthermore, in another embodiment, "elastic" means that the storage modulus at 23°C and 10Hz, as measured by dynamic viscoelasticity determination, is 1 MPa to 100 MPa. Examples of elastomers that may be included in thermoplastic elastomers other than styrene-based elastomers and acid-modified styrene-based elastomers include one or more selected from natural rubber, conjugated diene compound polymers, aromatic compound-conjugated diene copolymers, hydrides of aromatic compound-conjugated diene copolymers, polyolefins, polyester elastomers, polyurethane elastomers, polyamide elastomers, and elastomers having a core-shell structure. From the perspective of flexibility, 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 perspective of containing other components in the desired amount, it 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.

[0184] In one embodiment, the total ratio of styrene-based elastomer to acid-modified elastomer relative to 100% by mass of thermoplastic elastomer may be 1% or more by mass, or 5% or more by mass, or 10% or more by mass, or 20% or more by mass, or 50% or more by mass, or 70% or more by mass, and in another embodiment, it may be 100% by mass.

[0185] <Styrene-based elastomers and acid-modified styrene-based elastomers>

[0186] One type of resin composition comprises a styrene-based elastomer. Another type of resin composition comprises 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 conjugated diene monomers include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1,3-heptadiene, and 1,3-hexadiene, which can be used alone or in combination of two or more. Examples of aromatic vinyl monomers are not particularly limited to any monomer capable of copolymerizing with the conjugated diene monomer; for example, styrene, m-methylstyrene or p-methylstyrene, α-methylstyrene, ethylstyrene, p-tert-butylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, diphenylethylene, and divinylbenzene can be used alone or in combination of two or more. From the perspective of the processability of the resin composition and the impact resistance of the molded article, styrene is preferred.

[0187] Examples of random copolymers include butadiene-styrene random copolymers, isoprene-styrene random copolymers, and butadiene-isoprene-styrene random copolymers. Regarding the compositional distribution of monomers within the copolymer chain, examples include completely random copolymers with near-statistically random compositions and gradient random copolymers with a progressively changing compositional distribution. The bonding modes of conjugated diene polymers, i.e., 1,4-bonds, 1,2-bonds, etc., can be uniform or different between molecules.

[0188] Block copolymers can be copolymers composed of two or more blocks. For example, they can be block copolymers with structures such as AB, ABA, ABAB, etc., formed by blocks A (aromatic vinyl monomers) and B (conjugated diene monomers) and / or blocks B (polymers of aromatic vinyl monomers and conjugated diene monomers). It should be noted that the boundaries between the blocks do not necessarily need to be clearly defined. For example, when block B is a copolymer of aromatic vinyl monomers and conjugated diene monomers, the aromatic vinyl monomers in block B can be uniformly or progressively distributed. Furthermore, block B can contain portions with uniformly distributed aromatic vinyl monomers and / or portions with progressively distributed aromatic vinyl monomers. Moreover, block B can contain segments with different amounts of aromatic vinyl monomers. When multiple blocks A and blocks B exist in the copolymer, their molecular weights and compositions can be the same or different.

[0189] Styrene-based elastomers can also be aromatic vinyl compound-conjugated diene compound block copolymers or their hydrogenated forms. The block copolymers can be mixtures of two or more different compounds in terms of bonding type, molecular weight, type of aromatic vinyl compound, type of conjugated diene compound, 1,2-vinyl content or the combined content of 1,2-vinyl and 3,4-vinyl, aromatic vinyl compound content, and hydrogenation rate.

[0190] Styrene-based elastomers can be partially or fully hydrogenated. From the perspective of suppressing thermal degradation during processing, the hydrogenation rate of the hydride is preferably 50% or more, or 80% or more, or 98% or more; from the perspective of low-temperature toughness, it is preferably 50% or less, or 20% or less, or 0% (i.e., non-hydrogenated). Examples of hydrides of conjugated diene polymers, such as those exemplified above, include styrene-butadiene copolymers.

[0191] In one embodiment, the styrene-based elastomer is not acid-modified. In another embodiment, the styrene-based elastomer may be unmodified.

[0192] Acid-modified styrene-based elastomers can be acid-modified versions of the styrene-based elastomers exemplified above. In this disclosure, an acid-modified styrene-based elastomer refers to a styrene-based elastomer in which an acidic functional group is added via chemical bond as an acid-modifying group to the molecular backbone. Furthermore, in this disclosure, an acidic functional group refers to a functional group capable of reacting with basic functional groups, etc. Specific examples include hydroxyl, carboxyl, carboxylic acid ester, sulfonyl, and anhydride groups.

[0193] Regarding the mass ratio of acid-modified groups in 100% by mass of acid-modified styrene-based elastomer, i.e., the acid modification rate, from the perspective of reducing porosity due to good affinity with cellulose nanofibers, based on 100% by mass of acid-modified styrene-based elastomer, it 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. From the perspective of affinity with styrene-based elastomers, it is preferably 2.5% by mass or less, or 2.3% by mass or less, or 2% by mass or less. It should be noted that the acid modification rate is determined by measuring the sample with a standard curve premixed with acidic substances using an infrared absorption spectroscopy measuring device. The value is obtained by measuring the sample based on a standard curve prepared using the characteristic absorption band of acid.

[0194] In a preferred embodiment, the acid-modified styrene elastomer is an acid-modified styrene elastomer of an aromatic vinyl compound-conjugated diene compound copolymer (preferably an aromatic vinyl compound-conjugated diene compound block copolymer) or a styrene elastomer as a hydride thereof. Examples of such acid-modified styrene elastomers include modified elastomers obtained by grafting α,β-unsaturated dicarboxylic acids or their derivatives onto aromatic compound-conjugated diene copolymers (preferably block copolymers) or their hydrides in the presence or absence of peroxides. Specific examples of α,β-unsaturated dicarboxylic acids and their derivatives include maleic acid, fumaric acid, maleic anhydride, and fumaric anhydride, with maleic anhydride being particularly preferred. In a preferred embodiment, the acid-modified styrene elastomer is a styrene elastomer modified with an anhydride.

[0195] From the perspective of the dispersibility of cellulose nanofibers or compatibility with acid-modified styrene-based elastomers, 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-butene block copolymers, styrene-butadiene-butene block copolymers, styrene-isoprene block copolymers, styrene-ethylene-propylene block copolymers, styrene-isobutylene block copolymers, hydrides of styrene-butadiene block copolymers, hydrides of styrene-ethylene-butadiene block copolymers, hydrides of styrene-butadiene-butene block copolymers, hydrides of styrene-isoprene block copolymers, and homopolymers of styrene (polystyrene), more preferably one or more selected from the group consisting of styrene-butadiene block copolymers, hydrides of styrene-butadiene block copolymers, and polystyrene. From the perspective of compatibility with styrene-based elastomers, the acid-modified styrene-based elastomer is more preferably one or more acid-modified products exemplified above.

[0196] Regarding the styrene unit ratio of the acid-modified styrene-based elastomer and the unit ratio of the styrene-based elastomer, from the perspective of affinity with the acid-modified styrene-based elastomer and the styrene-based elastomer, and from the perspective of well exhibiting the advantageous properties inherent in the styrene-based elastomer, it is preferably 10% by mass or more, or 19% by mass or more, or 29% by mass or more; from the perspective of hardness, it is preferably 45% by mass or less, or 40% by mass or less, or 35% by mass or less. The styrene unit ratio is determined by the following method. Specifically, a specified amount of elastomer is dissolved in chloroform, and the content of aromatic vinyl monomer units (styrene) is measured using a UV spectrophotometer (e.g., Shimadzu UV-2450). The content of aromatic vinyl monomer units (styrene) is calculated using a standard curve based on the peak intensity of the absorption wavelength (262 nm) of the aromatic vinyl compound component (styrene).

[0197] Regarding the styrene unit ratio of the acid-modified styrene-based elastomer and the unit ratio of the styrene-based elastomer, from the perspective of affinity with the acid-modified styrene-based elastomer and the styrene-based elastomer, and from the perspective of good performance of the inherently advantageous properties of the styrene-based elastomer, it is preferably 10 mol% or more, or 15 mol% or more, or 20 mol% or more; from the perspective of the softness of the composition, it is preferably 40 mol% or less, or 35 mol% or less, or 30 mol% or less, or 25 mol% or less. These unit ratios are suitable for use in the manner of using an adhesive inhibitor containing cellulose nanofibers.

[0198] The styrene unit ratio was determined by NMR.

[0199] From the perspective of affinity with acid-modified styrene-based elastomers and styrene-based elastomers, the ratio of the styrene unit proportion of the styrene-based elastomer to the styrene unit proportion of the acid-modified styrene-based elastomer (styrene proportion of styrene-based elastomer / styrene proportion of acid-modified styrene-based elastomer) is preferably 0.3 or more, or 0.6 or more, or 0.9 or more, and from the same perspective, it is preferably 2.5 or less, or 2 or less, or 1.5 or less.

[0200] In acid-modified styrene-based elastomers, from the perspective of affinity with styrene-based elastomers, the ratio of styrene unit proportion to acid modification rate (styrene unit proportion / acid modification rate) is preferably 5 or more, or 10 or more, or 20 or more, and from the perspective of affinity with cellulose nanofibers, it is preferably 90 or less, or 85 or less, or 80 or less.

[0201] Regarding styrene-based elastomers and acid-modified styrene-based elastomers, the amount of vinyl bonds (e.g., 1,2- or 3,4-bonds of butadiene) in the conjugated diene polymer is preferably 5 mol% or more, or 10 mol% or more, or 13 mol% or more, or 15 mol% or more, 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.

[0202] The amount of vinyl bonds in a conjugated diene bond unit (e.g., the amount of 1,2-bonds in butadiene) can be determined by... 13 The result is obtained using C-NMR (quantitative model). That is, if... 13 By integrating the peak areas that appear in the following C-NMR, we can obtain a value proportional to the carbon content of each structural unit, and the result can be converted into the mass of each structural unit.

[0203] Styrene 145-147 ppm

[0204] Vinyl 110-116 ppm

[0205] Diene (cis) 24–28 ppm

[0206] Diene (trans) 29–33 ppm

[0207] In copolymers of conjugated diene monomers and aromatic vinyl monomers, the amount of aromatic vinyl monomers bonded to the conjugated diene monomers (also referred to herein as aromatic vinyl bonding amount) is preferably 5.0% to 70% by mass or 10% to 50% by mass relative to the total mass of the styrene-based elastomer. The aromatic vinyl bonding amount can be determined by the ultraviolet absorbance of the phenyl group, and the conjugated diene bonding amount can also be determined based on this.

[0208] From the perspective of affinity with styrene-based elastomers, 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, and from the perspective of affinity with cellulose nanofibers, it is preferably 500,000 or less, or 250,000 or less, or 200,000 or less.

[0209] From the perspective of balancing impact strength and flowability, the number average molecular weight (Mn) of styrene-based elastomers is preferably 10,000 to 500,000 or 40,000 to 250,000.

[0210] In a resin composition comprising 100% by mass, the total amount of acid-modified styrene-based elastomer and styrene-based elastomer is 60% by mass or more, or 65% by mass or more, or 70% by mass or more, or 75% by mass or more in one embodiment. Such a resin composition can exhibit good rubber elasticity, weather resistance, chemical resistance, etc. From the perspective of containing other components in desired amounts, particularly cellulose nanofibers, the above total amount is 90% by mass or less, or 85% by mass or less, or 80% by mass or less in one embodiment.

[0211] From the perspective of improving the surface smoothness of the molded body and the resistance to whitening during stretching (suppressing void formation), the amount of acid-modified styrene-based elastomer relative to 100 parts by mass of 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 perspective of suppressing coloring, shrinkage during molding and / or hardness reduction caused by a large amount of acid-modified styrene-based elastomer, it is preferably 50 parts by mass or less, or 40 parts by mass or less, or 30 parts by mass or less.

[0212] From the perspectives of improving the surface smoothness of the molded body and the resistance to whitening during stretching (suppressing void formation), the amount of acid-modified styrene-based elastomer relative to 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 perspectives of suppressing coloration, shrinkage during molding, and / or decrease in hardness caused by a large amount of acid-modified styrene-based elastomer, it 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 one type of resin composition, the acid-modified styrene-based elastomer may not be excessive compared to the number of hydroxyl groups on the surface portion of the cellulose nanofibers (specifically, the portion providing surface area in the specific surface area measurement of the cellulose nanofibers). The number of hydroxyl groups on 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 acid modifiers are used for chemical modification of cellulose nanofibers, sometimes an excessive amount of acid modifier is added relative to the cellulose nanofibers. However, in this embodiment, it is advantageous to set the amount of acid-modified styrene elastomer present in the resin composition to a necessary minimum, within the limit of obtaining the desired affinity with the cellulose nanofibers. From this perspective, the amount of acid-modified styrene elastomer is preferably adjusted in such a way that it is not excessive relative to the number of hydroxyl groups of the cellulose nanofibers, and the upper limit exemplified above is suitable from this perspective.

[0213] From the perspective of affinity with cellulose nanofibers, the amount of acid-modified group in the acid-modified styrene elastomer relative to 100% by mass of cellulose nanofibers is preferably 0.2% by mass or more, or 0.5% by mass or more, or 0.8% by mass or more, or 1.0% by mass or more, or 1.2% by mass or more, or 1.5% by mass or more. From the perspective of suppressing coloring, shrinkage during molding, and / or decrease in hardness caused by the acid-modified styrene elastomer, it 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.

[0214] From the perspectives of improving the surface smoothness of the molded article and its resistance to whitening during stretching (suppressing void formation), the amount of acid-modified styrene elastomer in 100% by mass of the resin composition is preferably 0.5% by mass or more, or 1% by mass or more, or 5% by mass or more. From the perspective of suppressing coloration, shrinkage during molding, and / or decrease in hardness caused by a large amount of acid-modified styrene elastomer, it is preferably 50% by mass or less, or 40% by mass or less, or 30% by mass or less. It should be noted that acid-modified styrene elastomers are generally quite expensive, and reducing the amount used is also advantageous in terms of cost.

[0215] In one approach, by selecting the type and / or amount of acid-modified styrene-based elastomer, the behavior of the stress-strain curve (e.g., yield behavior) of the resin composition in a tensile test can be controlled according to the desired use of the resin composition.

[0216] From the perspective of obtaining the good rubber elasticity, weather resistance and chemical resistance inherent in styrene-based elastomers, the amount of styrene-based elastomer relative to 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 perspective of improving the surface smoothness and hardness of the molded article, it is preferably 250 parts by mass or less, or 200 parts by mass or less, or 150 parts by mass or less.

[0217] From the perspective of effectively utilizing the inherently advantageous properties of styrene-based elastomers, the amount of styrene-based elastomers 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, and from the perspective of containing other components in desired amounts, it is preferably 98.8% by mass or less, or 90% by mass or less, or 80% by mass or less.

[0218] From the perspective of obtaining good mechanical properties of the resin composition, the melt flow rate (MFR) of the styrene 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, and from the perspective of facilitating melt processing, it 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.

[0219] <Styrene-based elastomers and acid-modified styrene-based elastomers using adhesive inhibitors containing cellulose nanofibers>

[0220] The following describes examples of styrene-based elastomers and acid-modified styrene-based elastomers, particularly preferred in the use of adhesive inhibitors containing cellulose nanofibers. In one embodiment, the resin composition contains an acid-modified styrene-based elastomer. It has been found that by including an acid-modified styrene-based elastomer in addition to cellulose nanofibers, the tensile strength, tensile modulus, elongation at break, and / or hardness of the molded article can be further improved, and undesirable conditions such as whitening and discoloration of the molded article can be reduced. Although not bound by theory, it is believed that the reaction between the hydroxyl groups of cellulose nanofibers and the acid-modified groups of the acid-modified styrene-based elastomer strengthens their interface, thereby reducing the likelihood of delamination between the styrene-based elastomer, cellulose nanofibers, and acid-modified styrene-based elastomer when external force is applied to the molded article, and reducing discoloration caused by thermal degradation of cellulose nanofibers. Thus, it is believed that the property improvement effect brought by cellulose nanofibers is well utilized, and the generation of voids in the molded article caused by delamination is suppressed, thereby reducing whitening and also suppressing the discoloration of cellulose nanofibers. The presence of acid-modified styrene elastomers in the resin composition is also advantageous in further reducing the viscosity caused by styrene elastomers.

[0221] In one embodiment of the resin composition, the acid-modified styrene-based elastomer and the styrene-based elastomer are compatible without phase separation and are a continuous phase. In another embodiment, the acid-modified styrene-based elastomer forms a first phase, and the styrene-based elastomer forms a second phase that separates from the first phase. 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. In one embodiment, the second phase is a continuous phase. In another embodiment, the first phase is a dispersed phase and the second phase is a continuous phase. The dispersed phase may, for example, have a phase domain size of 20 nm to 10 μm. It should be noted that the phase domain size can be determined by scanning electron microscopy (SEM) images. Alternatively, in one embodiment, the first phase and the second phase may each be a continuous phase. By allowing phase separation between the acid-modified styrene-based elastomer and the styrene-based elastomer, the styrene-based elastomer portion in the resin composition helps to exhibit the inherent good properties of the styrene-based elastomer. On the other hand, the acid-modified styrene-based elastomer portion in the resin composition, due to its good affinity with both the styrene-based elastomer and cellulose nanofibers, lies between the styrene-based elastomer and cellulose nanofibers, which helps to further enhance the physical property improvement effect brought about by cellulose nanofibers.

[0222] Acid-modified styrene-based elastomers can be acid-modified versions of the styrene-based elastomers exemplified above. Preferred acid-modified styrene-based elastomers are those exemplified above in this disclosure.

[0223] From the perspective of obtaining the good rubber elasticity, weather resistance and chemical resistance inherent in styrene-based elastomers, the amount of styrene-based elastomer relative to 1 part by mass of cellulose nanofibers 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 perspective of reducing the viscosity and increasing the hardness of the molded article, it is preferably 250 parts by mass or less, or 150 parts by mass or less, or 100 parts by mass or less.

[0224] From the perspective of obtaining the inherent advantages of styrene-based elastomers, the amount of styrene-based elastomer in 100% by mass of the resin composition is preferably 10% by mass or more, or 20% by mass or more, or 40% by mass or more, or 50% by mass or more, or 60% by mass or more, or 70% by mass or more, or 80% by mass or more. From the perspective of containing other components in desired amounts, it 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.

[0225] From the perspective of obtaining good mechanical properties of the resin composition, the melt flow rate (MFR) of the styrene 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, and from the perspective of facilitating melt processing, it 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.

[0226] Regarding the mass ratio of acid-modified groups in 100% by mass of acid-modified styrene-based elastomer, i.e., the acid modification rate, from the perspective of affinity with cellulose nanofibers, based on 100% by mass of acid-modified styrene-based elastomer, it 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. From the perspective of affinity with styrene-based elastomers, it 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.

[0227] From the perspective of affinity with acid-modified styrene-based elastomers and styrene-based elastomers, the ratio of the styrene unit proportion of the styrene-based elastomer to the styrene unit proportion of the acid-modified styrene-based elastomer (styrene proportion of styrene-based elastomer / styrene proportion of acid-modified styrene-based elastomer) is preferably 0.3 or more, or 0.35 or more, or 0.4 or more, and from the same perspective, it is preferably 4 or less, or 3 or less, or 2 or less.

[0228] In acid-modified styrene-based elastomers, from the perspective of affinity with styrene-based elastomers, the ratio of styrene unit proportion to acid modification rate (styrene unit proportion / acid modification rate) is preferably 5 or more, or 8 or more, or 12 or more, and from the perspective of affinity with cellulose nanofibers, it is preferably 90 or less, or 50 or less, or 30 or less.

[0229] From the perspective of affinity with styrene-based elastomers, the melt 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 perspective of affinity with cellulose nanofibers, it 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.

[0230] In a resin composition comprising 100% by mass, the total amount of acid-modified styrene-based elastomer and styrene-based elastomer is 50% by mass or more, or 60% by mass or more, or 70% by mass or more, or 80% by mass or more in one embodiment. Such a resin composition can exhibit good rubber elasticity, weather resistance, chemical resistance, etc. Regarding the presence of other components in desired amounts, particularly cellulose nanofibers, the above total amount is 99.5% by mass or less, or 99% by mass or less, or 98% by mass or less, or 95% by mass or less, or 90% by mass or less in one embodiment.

[0231] From the perspective of fully obtaining the advantages brought by acid-modified styrene elastomers, the amount of acid-modified styrene elastomer relative to 100 parts by weight of styrene elastomer is preferably 0.5 parts by weight or more, or 1 part by weight or more, or 5 parts by weight or more. From the perspective of suppressing coloring, shrinkage during molding and / or decrease in hardness caused by a large amount of acid-modified styrene elastomer, it is preferably 100 parts by weight or less, or 50 parts by weight or less, or 20 parts by weight or less, or 10 parts by weight or less.

[0232] From the perspective of fully obtaining the advantages brought by acid-modified styrene-based elastomers, the amount of acid-modified styrene-based elastomer relative to 1 part by mass of cellulose nanofibers 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 perspective of suppressing coloring, shrinkage during molding and / or decrease in hardness caused by a large amount of acid-modified styrene-based elastomers, it is preferably 45 parts by mass or less, or 30% by mass or less, or 20 parts by mass or less, or 10 parts by mass or less, or 5 parts by mass or less, or 3 parts by mass or less, or 2 parts by mass or less.

[0233] From the perspective of fully utilizing the advantages brought by acid-modified styrene elastomers, the amount of acid-modified styrene elastomer in 100% by mass of the resin composition is preferably 0.5% by mass or more, or 1% by mass or more, or 2% by mass or more, or 3% by mass or more, or 4% by mass or more. From the perspective of suppressing coloring, molding shrinkage, and / or hardness reduction caused by large amounts of acid-modified styrene elastomers, it 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. It should be noted that acid-modified styrene elastomers are generally expensive, and reducing the amount used is also advantageous in terms of cost.

[0234] In the resin composition, the content of styrene-based elastomer is preferably 10% by mass or more, or 20% by mass or more, preferably 90% by mass or less, or 85% by mass or less, or 80% by mass or less.

[0235] In the resin composition, the total content of styrene-based elastomer and acid-modified styrene-based elastomer is preferably 40% or more by mass, or 45% or more by mass, or 50% or more by mass, and preferably 99% or less by mass, or 95% or less by mass, or 90% or less by mass.

[0236] In the resin composition, relative to a total of 100 parts by mass of styrene-based elastomer and acid-modified styrene-based elastomer, the content of 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, preferably 70 parts by mass or less, or 65 parts by mass or less, or 60 parts by mass or less.

[0237] Relative to 100 parts by mass of the styrene-based elastomer and the acid-modified styrene-based elastomer, the amount of cellulose nanofibers in the resin composition is preferably 1 part by mass or more, or 2 parts by mass or more, or 3 parts by mass or more, preferably 70 parts by mass or less, or 65 parts by mass or less, or 60 parts by mass or less.

[0238] The preferred mass ratio of [cellulose nanofibers] / [total of styrene-based elastomer and acid-modified styrene-based elastomer] in the resin composition is 1 / 99 to 60 / 40, or 2 / 98 to 50 / 50, or 3 / 97 to 40 / 60.

[0239] Liquid polymers

[0240] In one embodiment, the resin composition may comprise a liquid polymer. A liquid polymer refers to a polymer that is fluid at 23°C. In one embodiment, the liquid polymer has a glass transition temperature (Tg). In one embodiment, the liquid polymer may be a conjugated diene polymer or a non-conjugated diene polymer. In one embodiment, the liquid polymer is a liquid rubber. In this disclosure, liquid rubber refers to a substance that is fluid at 23°C and forms a rubber elastomer through crosslinking (more specifically, vulcanization) and / or chain extension. That is, in one embodiment, the liquid rubber is an uncured material.

[0241] In addition, having fluidity means that, in one method, a liquid polymer dissolved in cyclohexane is placed into a vial with a diameter of 21 mm and a length of 50 mm at 23°C, and then dried, thereby filling the vial to a height of 1 mm. The vial is then sealed, and after standing for 24 hours with the vial upside down, it can be confirmed that the substance has moved more than 0.1 mm in the height direction.

[0242] Liquid polymers can have a typical polymer monomer composition, and a lower molecular weight is preferred from the perspectives of ease of handling and good dispersibility of cellulose nanofibers. In one embodiment, liquid polymers are formed by having a number-average molecular weight (Mn) of 80,000 or less. It should be noted that, unless otherwise stated, the number-average and weight-average molecular weights of the various polymers disclosed herein are values ​​obtained by gel permeation chromatography using chloroform as a solvent, at a determination temperature of 40°C, and converted from standard polystyrene.

[0243] In one embodiment, the liquid polymer can be combined with cellulose nanofibers to form a masterbatch, which can then be combined with a resin to form the resin composition disclosed herein.

[0244] From the perspective of thermal stability and improving the dispersibility of cellulose nanofibers in resin, 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 perspective of having high fluidity suitable for achieving good dispersion when dispersing cellulose nanofibers in the liquid polymer, it is preferably 80,000 or less, or 50,000 or less, or 40,000 or less, or 30,000 or less, or 10,000 or less.

[0245] From the perspective of thermal stability and improving the dispersibility of cellulose nanofibers in resin, 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, and from the perspective of having high fluidity suitable for achieving good dispersion when dispersing cellulose nanofibers in the liquid polymer, it is preferably 240,000 or less, or 150,000 or less, or 30,000 or less.

[0246] Regarding the ratio of number-average molecular weight (Mn) to weight-average molecular weight (Mw) of the liquid polymer (Mw / Mn), from the perspective of being able to achieve a high level of balance between multiple properties (in one aspect, a high level of balance between good dispersion of cellulose nanofibers in the resin and good flexural modulus of the resin composition) by allowing a certain degree of fluctuation in molecular weight, it is preferably 1.5 or more, or 1.8 or more, or 2 or more. From the perspective of being able to stably obtain the desired physical properties of the resin composition without excessive fluctuation in molecular weight, for example, from the perspective of balancing flowability and impact resistance, it is preferably 10 or less, or 8 or less, or 5 or less, or 3 or less, or 2.7 or less.

[0247] Liquid polymers can exhibit good thermal stability. Regarding the thermal decomposition onset temperature (T0) of liquid polymers... D From the perspective of good thermal stability, in one embodiment, the temperature is above 200°C, or above 210°C, or above 230°C, or above 250°C, or above 300°C. A high thermal decomposition onset temperature is preferred. From the perspective of ease of obtaining the liquid polymer, in one embodiment, the temperature is below 500°C, or below 450°C, or below 400°C.

[0248] From the perspective of good thermal stability, the glass transition temperature of the liquid polymer is preferably above -150°C, or above -120°C, or above -100°C. From the perspective of good fluidity, it is preferably below 25°C, or below 10°C, or below 0°C.

[0249] The liquid polymer comprises, in one embodiment, a diene polymer, and in another embodiment, a conjugated diene polymer or a non-conjugated diene polymer or its hydrides. The polymer or its hydrides may be oligomers. The monomers constituting the liquid polymer may be unmodified or modified (e.g., acid-modified, hydroxyl-modified, etc.). In one embodiment, the liquid polymer may have reactive groups at both ends (e.g., selected from one or more groups consisting of hydroxyl, carboxyl, isocyanate, thio, amino, and halogen groups), thus being bifunctional. These reactive groups facilitate crosslinking and / or chain extension of the liquid polymer.

[0250] [Conjugated diene polymers]

[0251] Conjugated diene polymers can be homopolymers, or copolymers of two or more conjugated diene monomers, or copolymers of conjugated diene monomers with other monomers. Copolymers can be either random or block copolymers.

[0252] Examples of conjugated diene monomers include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1,3-heptadiene, and 1,3-hexadiene, which can be used alone or in combination of two or more.

[0253] In one embodiment, the conjugated diene polymer is a copolymer of the aforementioned conjugated diene monomer and an aromatic vinyl monomer.

[0254] As an aromatic vinyl monomer, there are no particular limitations on any monomer that can copolymerize with a conjugated diene monomer. Examples include styrene, m-methylstyrene or p-methylstyrene, α-methylstyrene, ethylstyrene, p-tert-butylstyrene, vinyl ethylbenzene, vinylxylene, vinylnaphthalene, diphenylethylene, and divinylbenzene. These can be used alone or in combination of two or more. Styrene is preferred from the perspective of the processability of the resin composition and the impact resistance of the molded article.

[0255] Examples of random copolymers include butadiene-isoprene random copolymers, butadiene-styrene random copolymers, isoprene-styrene random copolymers, and butadiene-isoprene-styrene random copolymers. Regarding the compositional distribution of monomers in the copolymer chain, examples include completely random copolymers with statistically close random compositions, and gradient random copolymers with a progressively changing compositional distribution. The bonding modes of conjugated diene polymers, such as 1,4-bonding and 1,2-bonding, can be homogeneous or differentiated between molecules.

[0256] Block copolymers can be copolymers composed of two or more blocks. For example, they can be block copolymers with structures such as AB, ABA, and ABAB, formed by blocks A (of aromatic vinyl monomers) and blocks B (block B being a block of a conjugated diene monomer and / or a block of a copolymer of aromatic vinyl monomers and conjugated diene monomers). Furthermore, the boundaries between blocks do not necessarily need to be clearly defined. For example, in the case where block B is a copolymer of aromatic vinyl monomers and conjugated diene monomers, the aromatic vinyl monomers in block B can be uniformly distributed or progressively distributed. Additionally, there can be multiple uniformly distributed and / or progressively distributed portions of aromatic vinyl monomers in block B. Moreover, there can be multiple segments in block B with different contents of aromatic vinyl monomers. When multiple blocks A and multiple blocks B exist in the copolymer, their molecular weights and compositions can be the same or different.

[0257] Block copolymers can be mixtures of two or more different types of bonding methods, molecular weight, types of aromatic vinyl compounds, types of conjugated diene compounds, 1,2-vinyl content or the total content of 1,2-vinyl and 3,4-vinyl, aromatic vinyl compound content, hydrogenation rate, etc.

[0258] The amount of vinyl bonds (e.g., 1,2- or 3,4-bonding of butadiene) in the conjugated diene polymer is preferably 10 mol% or more and 75 mol% or less, or 13 mol% or more and 65 mol% or less.

[0259] The amount of vinyl bonds in a conjugated diene bond unit (e.g., the amount of 1,2-bonds in butadiene) can be determined by... 13 The result is obtained using C-NMR (quantitative model). That is, if... 13 By integrating the peak areas that appear in the following C-NMR, we can obtain a value proportional to the carbon content of each structural unit, and the result can be converted into the mass of each structural unit.

[0260] Styrene 145-147 ppm

[0261] Vinyl 110-116 ppm

[0262] Diene (cis) 24–28 ppm

[0263] Diene (trans) 29–33 ppm

[0264] In the copolymer of conjugated diene monomer and aromatic vinyl monomer, the amount of aromatic vinyl monomer bonded to the conjugated diene monomer (also referred to in this disclosure as aromatic vinyl bond amount) is preferably 5 mol% to 70 mol% or 10 mol% to 50 mol% of the total molar amount of the conjugated diene polymer.

[0265] Examples of hydrides of conjugated diene polymers include those exemplified above, such as butadiene homopolymers, isoprene homopolymers, styrene-butadiene copolymers, and acrylonitrile-butadiene copolymers.

[0266] In a preferred embodiment, the liquid polymer is one or more selected from the group consisting of polybutadiene, butadiene-styrene copolymer, polyisoprene, and polychloroprene. These polymers may be derivatives (e.g., maleic anhydride modified, methacrylic acid modified, terminal hydroxyl modified, hydrides, and combinations thereof).

[0267] [Non-conjugated diene polymers]

[0268] Non-conjugated diene polymers can be homopolymers, copolymers of two or more non-conjugated diene monomers, or copolymers of non-conjugated diene monomers with other monomers. The copolymer can be either random or block copolymers. Examples of non-conjugated diene polymers include olefin polymers (e.g., liquid paraffin), silicone polymers, and acrylic polymers. For example, examples of non-conjugated diene polymers that are liquid rubbers as liquid polymers 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, polyvinyl chloride rubber, epichlorohydrin rubber, α,β-unsaturated nitrile-acrylate-conjugated diene copolymer rubber, urethane rubber, polysulfide rubber, etc.

[0269] In ethylene-α-olefin copolymers, monomers that can copolymerize with ethylene units include aliphatic substituted vinyl monomers such as propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tetracene, 1-tetradecene, 1-pentadecadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecadecene, or 1-eicosene, isobutene, as well as aromatic vinyl monomers such as styrene and substituted styrene, ester vinyl monomers such as vinyl acetate, acrylate, methacrylate, glycidyl acrylate, glycidyl methacrylate, hydroxyethyl methacrylate, acrylamide, allylamine, vinyl-p-aminobenzene, acrylonitrile, butadiene, cyclopentadiene, 1,4-hexadiene, isoprene, etc.

[0270] 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.

[0271] Regarding the molecular weight of the ethylene-α-olefin copolymer, from the perspective of exhibiting impact resistance, the number average molecular weight (Mn) (which is determined by gel permeation chromatography using 1,2,4-trichlorobenzene as a solvent and polystyrene standard at 140°C) 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.

[0272] Furthermore, from the perspective of processability, the content of ethylene units in the ethylene-α-olefin copolymer is preferably 30% to 95% by mass relative to the total amount of the ethylene-α-olefin copolymer.

[0273] Ethylene-α-olefin copolymers can be manufactured, for example, by the known manufacturing methods described in Japanese Patent Application Publication No. 4-12283, Japanese Patent Application Publication No. 60-35006, Japanese Patent Application Publication No. 60-35007, Japanese Patent Application Publication No. 60-35008, Japanese Patent Application Publication No. 5-155930, Japanese Patent Application Publication No. 3-163088, and US Patent No. 5272236.

[0274] In one embodiment, the liquid polymer comprises one or more selected from the group consisting of diene rubbers, silicone rubbers, urethane rubbers, and polysulfide rubbers and their hydrides, preferably including diene rubbers.

[0275] From the perspective of ensuring good dispersion of cellulose nanofibers in the liquid polymer, 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 perspective of thermal stability, the effect of improving the dispersibility of cellulose nanofibers in the resin, and the mechanical properties of the resin composition, it is preferably 100 mPa·s or more, or 300 mPa·s or more, or 500 mPa·s or more.

[0276] From the perspective of effectively dispersing cellulose nanofibers in a liquid polymer and effectively dispersing cellulose nanofibers in a resin through heating and mixing, 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 perspective of thermal stability, the effect of improving the dispersibility of cellulose nanofibers in the resin, and the mechanical properties of the resin composition, it is preferably 50 mPa·s or more, or 100 mPa·s or more, or 500 mPa·s or more.

[0277] From the perspective of ensuring good dispersion of cellulose nanofibers in the liquid polymer and good dispersion of cellulose nanofibers in the resin through heating and mixing, 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 perspective of thermal stability, the effect of improving the dispersibility of cellulose nanofibers in the resin, and the mechanical properties of the resin composition, it is preferably 50 mPa·s or more, or 100 mPa·s or more, or 300 mPa·s or more.

[0278] From the perspective of ensuring good dispersion of cellulose nanofibers in a liquid polymer, 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 perspective of thermal stability, the effect of improving the dispersibility of cellulose nanofibers in the resin, and the mechanical properties of the resin composition, it is preferably 200 mPa·s or more, or 600 mPa·s or more, or 1,000 mPa·s or more.

[0279] From the perspective of being able to disperse cellulose nanofibers well in liquid polymers over a wide range of mixing temperatures, it is preferable that the viscosity of the liquid polymer is within the above-mentioned ranges at 80°C, 50°C, 25°C and 0°C.

[0280] The viscosity of the liquid polymer was measured using a Type B viscometer at a rotation speed of 10 rpm.

[0281] In the resin composition, from the viewpoint of obtaining the advantages of liquid polymer well, the amount of liquid polymer relative to 100 parts by mass of styrene 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 parts by mass or more. From the viewpoint of obtaining the advantages of acid-modified styrene elastomer well, or obtaining a resin composition exhibiting the original physical properties of styrene elastomer, it is preferably 15 parts by mass or less, or 10 parts by mass or less, or 5 parts by mass or less.

[0282] In the resin composition, from the viewpoint of obtaining the advantages of liquid polymer well, the amount of liquid polymer relative to 100 parts by mass of cellulose nanofiber is preferably 5 parts by mass or more, or 10 parts by mass or more, or 20 parts by mass or more, or 30 parts by mass or more, or 40 parts by mass or more, and from the viewpoint of obtaining good physical properties of resin composition and resin molded article, it is preferably 400 parts by mass or less, or 200 parts by mass or less, or 100 parts by mass or less.

[0283] From the perspective of obtaining the advantages of liquid polymers, the content of liquid polymer in the resin composition is preferably 0.1% by mass or more, or 0.3% by mass or more, or 1.0% by mass or more, and from the perspective of obtaining good physical properties of the resin composition and the resin molded article, it is preferably 20% by mass or less, or 10% by mass or less, or 7% by mass or less, or 5% by mass or less.

[0284] <Dispersant>

[0285] In one embodiment, the resin composition includes a dispersant. In another embodiment, for the purpose of more uniformly dispersing the cellulose nanofibers in the resin composition, the dispersant further preferably has both hydrophilic and hydrophobic segments (i.e., amphiphilic molecules) within the same molecule. In a preferred embodiment, the resin composition includes a polymer containing polyoxyethylene units.

[0286] [Amphiphilic molecules]

[0287] In amphiphilic molecules, the hydrophilic segment is the part that exhibits good affinity with cellulose nanofibers by containing a hydrophilic structure. Specifically, the hydrophilic structure includes groups such as hydroxyl, mercapto, carboxyl, sulfonic acid, sulfate, phosphate, borate, silanol, groups derived from sugars such as sorbitan anhydride and sucrose, groups derived from glycerol, groups represented by -OM, -COOM, -SO3M, -OSO3M, -HMPO4, and -M2PO4 (where M represents an alkali metal or alkaline earth metal), as well as primary to tertiary amines and quaternary ammonium salts. Examples of the quaternary ammonium salt's balancing anion include halide ions selected from groups such as hydroxide ions, fluoride ions, chloride ions, bromide ions, iodide ions, nitrate ions, formate ions, acetate ions, trifluoroacetate ions, p-toluenesulfonate ions, hexafluorophosphate, and tetrafluoroborate.

[0288] Examples of hydrophilic segments include segments of polyethylene glycol, segments containing repeating units comprising quaternary ammonium salt structures, segments of polyvinyl alcohol, segments of polyvinylpyrrolidone, segments of polyacrylic acid, segments of carboxyvinyl polymers, segments of cationic guar gum, segments of hydroxyethyl cellulose, segments of methyl cellulose, segments of carboxymethyl cellulose, and soft segments of polyurethane (specifically, glycol segments). Nonionic polyoxyethylene derivatives are particularly preferred, and the polyoxyethylene chain length of the polyoxyethylene derivative can be 3 or more, or 5 or more, or 10 or more, or 15 or more. The longer the chain length, the greater the affinity with cellulose nanofibers. From the perspective of balancing with the desired properties (e.g., mechanical properties) of the resin molded body, the polyoxyethylene chain length can be 60 or less, or 50 or less, or 40 or less, or 30 or less, or 20 or less.

[0289] Examples of hydrophobic segments include segments containing hydrocarbons, segments containing fluorinated carbon, segments containing 3 or more carbon alkylene oxide units (e.g., PPG blocks), and segments containing polymer structures.

[0290] As the hydrocarbon segment, alkyl, alkenyl, alkyl ether, alkenyl ether, alkylphenyl ether, alkenylphenyl ether, rosin ester, bisphenol A, β-naphthyl, styrene-modified phenyl, and hydrogenated castor oil types are preferred. The number of carbon atoms in the hydrophobic alkyl or alkenyl chain (excluding phenyl atoms in the case of alkylphenyl or alkenylphenyl) is preferably 2 or more, or 5 or more, or 10 or more, or 12 or more, or 16 or more.

[0291] As for the segments containing fluorinated carbon, linear or branched alkyl types with 1 to 20 carbon atoms are preferred.

[0292] Preferred polymer segments include acrylic polymers, styrene resins, vinyl chloride resins, vinylidene chloride resins, polyolefin resins, amino acid lactams of ring-opening polymers containing lactams, polymers composed of diamines and dicarboxylic acids, polyacetal resins, polycarbonate resins, polyester resins, polyphenylene sulfide resins, polysulfone resins, polyetherketone resins, polyimide resins, fluorine resins, hydrophobic silicone resins, melamine resins, epoxy resins, and phenolic resins.

[0293] These hydrophobic segments can be either straight-chain or branched-chain structures. Furthermore, the hydrophobic segments can be one chain or two or more chain structures; when they are two or more chain structures, they can possess a variety of hydrophobic groups.

[0294] There are no particular restrictions on the structure of amphiphilic molecules. When the hydrophilic segment is A and the hydrophobic segment is B, examples include linear copolymers such as AB-type block copolymers, ABA-type block copolymers, and BAB-type block copolymers; 3-branched copolymers containing A and B; 4-branched copolymers containing A and B; star-shaped copolymers containing A and B; monocyclic copolymers containing A and B; polycyclic copolymers containing A and B; cage-like copolymers containing A and B; and graft copolymers containing A and B.

[0295] When a molecule contains multiple hydrophilic segments, its molecular structure can be a single type or a combination of two or more types. Similarly, when a molecule contains multiple hydrophobic segments, its molecular structure can be a single type or a combination of two or more types.

[0296] (surfactant)

[0297] As an amphiphilic molecule, it can be any of anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants. The dispersant can be a polymeric surfactant, a reactive surfactant, etc.

[0298] Examples of nonionic surfactants include: fatty acid dialkylolamides (e.g., lauric acid diethanolamide), polyoxyethylene fatty acid amides (e.g., polyoxyethylene stearamide), polyoxyethylene aryl ethers (e.g., polyoxyethylene phenyl ether), polyoxyethylene alkyl aryl ethers (e.g., polyoxyethylene octylphenyl ether), polyoxyethylene alkyl or alkenyl ethers (e.g., polyoxyethylene lauryl ether, polyoxyethylene stearyl ether), fatty acid esters of polyols (e.g., polyethylene glycol mono- or distearate, polyethylene glycol mono- or dilaurate, polyoxyethylene hydrogenated castor oil), glycerol fatty acid esters (e.g., glyceryl monostearate, glyceryl monooleate), sorbitol fatty acid esters (e.g., sorbitol monolaurate, sorbitol monostearate), polyoxyethylene-polyoxypropylene block polymers, etc.

[0299] Anionic surfactants (emulsifiers) can be carboxylates, sulfonates, sulfates, phosphates, etc. For example, carboxylates can include aliphatic monocarboxylic acids and alkyl ether carboxylates; sulfonates can include dialkyl sulfosuccinates, alkane sulfonates, alkylbenzene sulfonates, and alkylnaphthalene sulfonates; sulfates can include alkyl sulfates and oil sulfates; and phosphates can include alkyl phosphates and polyoxyethylene alkyl ether phosphates.

[0300] Examples of cationic surfactants include amine salts, amide amine salts, quaternary ammonium salts, and imidazoline salts. Specific examples, without particular limitation, include alkyl amine salts, polyoxyethylene alkyl amine salts, alkyl amide amine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, imidazoline and other amine salt surfactants, alkyl trimethylammonium salts, dialkyl dimethylammonium salts, alkyl dimethyl benzylammonium salts, alkyl pyridinium salts, alkyl isoquinolineium salts, benzyl chloride and other quaternary ammonium salt surfactants.

[0301] Examples of amphoteric surfactants include alkyl amine oxides, alanine oxides, imidazoline betaines, amide betaines, and acetate betaines. More specifically, examples include long-chain amine oxides, lauryl betaine, stearyl betaine, lauryl carboxymethyl hydroxyethyl imidazoline betaine, lauryl dimethyl aminoacetic acid betaine, and fatty acid amide propyl dimethyl aminoacetic acid betaine.

[0302] [Hydrophilic polymer]

[0303] In one embodiment, the dispersant is preferably a hydrophilic polymer. In another embodiment, the hydrophilic polymer is a polymer having a hydrophilic group selected from the group consisting of hydroxyl, carboxyl, amino, ammonium, sulfonic acid, and phosphate groups. As the hydrophilic polymer, one or more can be used selected from the group consisting of cellulose derivatives (hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, etc.), polyalkylene glycols, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, carboxyvinyl polymers, cationic guar gum, water-soluble polyurethane, polymers containing quaternary ammonium salt structures, amides, and amines. Cellulose derivatives and polyalkylene glycols are more preferred, and polyalkylene glycols are particularly preferred.

[0304] The amount of dispersant in the resin composition relative to 100 parts by weight of cellulose nanofibers is preferably 1 part by weight or more, or 3 parts by weight or more, or 5 parts by weight or more, or 10 parts by weight or more, or 15 parts by weight or more, preferably 200 parts by weight or less, or 150 parts by weight or less, or 100 parts by weight or less, or 90 parts by weight or less, or 80 parts by weight or less, or 70 parts by weight or less, or 60 parts by weight or less, or 50 parts by weight or less.

[0305] In one embodiment, the content of the dispersant in the resin composition may be 0.1% by mass or more, or 0.5% by mass or more, or 1% by mass or more; in another embodiment, it may be 40% by mass or less, or 35% by mass or less, or 30% by mass or less.

[0306] For example, when a preparative composition comprising cellulose nanofibers and an acid-modified styrene-based elastomer is supplied in the manufacture of a resin composition, the mass ratio of the preparative composition to the styrene-based elastomer (preparative composition / styrene-based elastomer) in the resin composition may, in one embodiment, be 1 / 99 to 99 / 1, or 5 / 95 to 95 / 5, or 10 / 90 to 90 / 10, or 20 / 80 to 80 / 20, or 30 / 70 to 70 / 30.

[0307] [Vulcanizing agent, vulcanization accelerator]

[0308] When the resin composition contains liquid rubber, it typically contains a vulcanizing agent and optionally a vulcanization accelerator. The vulcanizing agent and vulcanization accelerator can be appropriately selected from existing known vulcanizing agents and vulcanization accelerators depending on the type of liquid rubber in the resin composition. As vulcanizing agents, organic peroxides, azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur, sulfur compounds, etc., can be used. Examples of sulfur compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, and high molecular weight polysulfide compounds.

[0309] The amount of vulcanizing agent in the resin composition is preferably 0.01 to 20 parts by mass or 0.1 to 15 parts by mass relative to 100 parts by mass of liquid rubber in the resin composition.

[0310] Examples of vulcanization accelerators include sulfenamide-based, guanidine-based, thiuram-based, aldehyde-amine-based, aldehyde-amine-based, thiazole-based, thiourea-based, and dithiocarbamate-based accelerators. Additionally, zinc oxide and stearic acid can be used as vulcanization aids. The amount of vulcanization accelerator is preferably 0.01 to 20 parts by weight, or 0.1 to 15 parts by weight, relative to 100 parts by weight of liquid rubber in the resin composition.

[0311] [Additives for Rubber]

[0312] The resin composition can contain various known rubber additives (stabilizers, softeners, anti-aging agents, etc.). As a 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 can be used. Additionally, as a rubber softener, one or more processing oils, extender oils, etc., can be used. However, since the resin composition of this embodiment can form a soft molded body in one embodiment, the resin composition may not contain a rubber softener in one embodiment.

[0313] It should be noted that vulcanizing agents, vulcanization accelerators, and rubber additives are typically added during the manufacture of the resin composition, but the manner of addition is not limited to this.

[0314] <Additional components to the resin composition>

[0315] The resin composition may further include additional components. Examples of additional components include polymers, organic or inorganic fillers, heat stabilizers, antioxidants, antistatic agents, colorants, etc. The proportion of any additional component in the resin composition may be appropriately selected within a range that does not impair the desired effects of the present invention, for example, it may be 0.01% to 50% by mass, or 0.1% to 30% by mass.

[0316] <Preparation of Resin Compositions>

[0317] One method of resin composition is to manufacture by mixing components as a mixture comprising cellulose nanofibers, acid-modified styrene elastomers, and styrene elastomers.

[0318] One method of manufacturing a resin composition is by mixing components of a composition comprising a viscosity inhibitor containing cellulose nanofibers and a styrene-based elastomer.

[0319] The mixing process involves heating and kneading.

[0320] That is, one method of manufacturing a resin composition includes a mixing step of heating and mixing a mixture comprising a styrene-based elastomer and cellulose nanofibers.

[0321] The weight gain rate of the cellulose nanofibers after heat mixing relative to the cellulose nanofibers before heat mixing is preferably 190% to 600%. From the perspective of the interfacial strength between the resin and the cellulose nanofibers, the weight gain rate is preferably 190% or more, or 250% or more, or 300% or more, or 350% or more; from the perspective of suppressing short fiber formation during mixing, it is preferably 600% or less, or 550% or less, or 500% or less. The weight gain rate is a value measured by the method described in one of the [Examples] of this disclosure.

[0322] As a method for manufacturing a resin composition, examples include the use of acid-modified styrene-based elastomers: (1) A method comprising a first step of mixing cellulose nanofibers with an acid-modified styrene-based elastomer to obtain a preparative composition; and a second step of mixing the preparative composition with a styrene-based elastomer to obtain a resin composition; (2) A method including a process of mixing resin composition components comprising cellulose nanofibers, acid-modified styrene elastomers and styrene elastomers in a single step; etc.

[0323] Without using acid-modified styrene-based elastomers, the resin composition components containing cellulose nanofibers and styrene-based elastomers can be mixed in one step in the method described in (2) above.

[0324] There are no particular limitations on the mixing conditions. For example, the components constituting the resin composition can be mixed using various mixing methods such as a rotary mixer, planetary mixer, propeller agitator, rotary mixer, electromagnetic agitator, open mill, Banbury mixer, kneader, single-screw extruder, and twin-screw extruder to obtain the resin composition. Additionally, stirring under heat can be performed to effectively induce shearing.

[0325] In the method described in (1) above, by combining the acid-modified styrene elastomer with cellulose nanofibers in advance, the contact opportunities between the cellulose nanofibers and the styrene elastomer become more moderate and uniform, thus the physical properties of the resin composition can be improved more effectively.

[0326] Cellulose nanofibers supplied for mixing with acid-modified styrene-based elastomers or styrene-based elastomers can be in the form of a dried body containing cellulose nanofibers. In one embodiment, cellulose nanofibers can be mixed with a liquid polymer and / or dispersant in slurry form, and the contained liquid medium can be dried to remove it, resulting in a dried body containing cellulose nanofibers. This drying process can be carried out, for example, as follows.

[0327] [Drying Process]

[0328] In one approach, a dried body containing cellulose nanofibers can be manufactured by drying a cellulose nanofiber slurry.

[0329] As for dryers, there are no particular limitations; examples include kneaders, planetary mixers, Henschel mixers, high-speed mixers, propeller mixers, ribbon mixers, single-screw or twin-screw screw extruders, Banbury mixers, freeze dryers, shed dryers, spray dryers, fluidized bed dryers, and drum dryers.

[0330] From the perspective of forming a dried body of cellulose nanofibers with excellent powder properties including excellent nano-dispersion and macro-dispersion of cellulose nanofibers in the resin composition and drying efficiency, the drying temperature can be, for example, above 20°C, or above 30°C, or above 40°C, or above 50°C. From the perspective of not easily generating thermal degradation of cellulose nanofibers and additional components, and avoiding excessive micronization of the dried body containing cellulose nanofibers due to rapid drying of the slurry, the drying temperature can be, for example, below 200°C, or below 180°C, or below 160°C, or below 140°C, or below 120°C, or below 100°C.

[0331] Drying temperature is the temperature of the heat source in contact with the slurry, such as the surface temperature of the temperature-regulating sleeve of the drying device, the surface temperature of the heating cylinder, or the temperature of the hot air.

[0332] The pressure can be either atmospheric pressure or reduced pressure. From the perspective of forming a dry body of cellulose nanofibers with excellent powder properties including drying efficiency and excellent nano-dispersion and macro-dispersion of cellulose nanofibers in the resin composition, it can be below -1 kPa, or below -10 kPa, or below -20 kPa, or below -30 kPa, or below -40 kPa, or below -50 kPa. From the perspective of avoiding excessive micronization of the dry body containing cellulose nanofibers due to rapid drying of the slurry, it can be above -100 kPa, or above -95 kPa, or above -90 kPa.

[0333] From the perspective of process efficiency during drying, the concentration of cellulose nanofibers in the cellulose nanofiber slurry supplied for the drying process is preferably 1% by mass or more, or 2% by mass or more, or 3% by mass or more, or 5% by mass or more, or 10% by mass or more, or 15% by mass or more, or 20% by mass or more, or 25% by mass or more. From the perspective of avoiding excessive increase in slurry viscosity and maintaining good workability due to solidification caused by agglomeration, it is preferably 50% by mass or less, or 45% by mass or less, or 40% by mass or less, or 35% by mass or less. For example, the manufacture of cellulose nanofibers is mostly carried out in a dilute dispersion, but the concentration of cellulose nanofibers in the slurry can also be adjusted to the above-mentioned preferred range by concentrating such a dilute dispersion. Concentration can be achieved by methods such as vacuum filtration, pressure filtration, centrifugation, and heating.

[0334] In one embodiment, the dried body containing cellulose nanofibers may contain liquid polymers and / or dispersants, which may be added before, during, and / or after drying the cellulose nanofiber slurry.

[0335] 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. There are no particular limitations on the organic solvent, but solvents for dissolving the liquid polymer and dispersant are preferred, including non-water-soluble solvents such as chloroform, toluene, hexane, and cyclohexane.

[0336] [Liquid Medium Content]

[0337] From the perspective of operability when compounding with acid-modified styrene-based elastomers or styrene-based elastomers, the liquid medium content of the dried body containing cellulose nanofibers is preferably 50% by mass or less, or 40% by mass or less, or 30% by mass or less, or 20% by mass or less, or 10% by mass or less. From the perspective of viscosity-inhibiting effect, a liquid medium content of 7% by mass or less, or 5% by mass or less, or 3% by mass or less is particularly preferred. The liquid medium content can also be 0% by mass, but from the perspective of ease of manufacturing the dried body containing cellulose nanofibers, it can 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.

[0338] [Average Particle Size]

[0339] In one embodiment, from the perspective of ease of manufacture, the average particle size of the dried body containing cellulose nanofibers is preferably 1 μm or more, or 10 μm or more, 50 μm or more, or 100 μm or more, or 200 μm or more, or 500 μm or more. From the perspective of the dried body containing cellulose nanofibers readily disintegrating in the resin composition, thereby enabling good dispersion of the cellulose nanofibers in the resin composition, it is preferably 10000 μm or less, or 5000 μm or less, or 4000 μm or less, or 3000 μm or less, or 2000 μm or less. The above-mentioned average particle size is a value measured using a dynamic image analysis particle size distribution measuring device (CAMSIZER X2, Microtrac Corporation).

[0340] Loose bulk density

[0341] In one embodiment, considering the good flowability and excellent feedability of the dried body containing cellulose nanofibers, and the suppression of the transfer of liquid polymers and / or dispersants into the resin composition, the loose bulk density of the dried body containing cellulose nanofibers is preferably 0.01 g / cm³. 3 Above, or 0.05g / cm 3 Above, or 0.10 g / cm 3 Above, or 0.15g / cm 3 Above, or 0.20 g / cm 3 Above, or 0.25g / cm 3 Above, or 0.30 g / cm 3 Above, or 0.35g / cm 3 Above, or 0.40 g / cm 3 Above, or 0.45g / cm 3 Above, or 0.50 g / cm 3 Based on the above, considering that the dried body containing cellulose nanofibers readily disintegrates in the resin composition, thus enabling good dispersion of the cellulose nanofibers in the resin composition, and that the dried body containing cellulose nanofibers is not too heavy, thus avoiding poor mixing between the dried body containing cellulose nanofibers and the resin composition, the loose bulk density of the dried body containing cellulose nanofibers is preferably 0.85 g / cm³. 3 Below, or 0.80g / cm 3 Below, or 0.75g / cm 3 the following.

[0342] [Tap density]

[0343] In one embodiment, the tap density of the dried body containing cellulose nanofibers is controlled within a range useful for controlling the loose bulk density and compressibility within the scope of this disclosure, preferably 0.01 g / cm³ in one embodiment. 3 Above, or 0.1 g / cm 3 Above, or 0.15g / cm 3 Above, or 0.2g / cm 3 Above, or 0.3g / cm 3 Above, or 0.4 g / cm 3 Above, or 0.5g / cm 3 Above, or 0.6 g / cm 3 The above, preferably 0.95 g / cm³ 3 Below, or 0.9g / cm 3 Below, or 0.85g / cm 3 the following.

[0344] [Compression]

[0345] The compressibility is calculated as compressibility = (tap density - loose bulk density) / tap density. The loose bulk density and tap density are values ​​determined by the method described in one of the [Examples] of this disclosure.

[0346] In one embodiment, compressibility refers to the degree of volume reduction. In one embodiment, considering that the flowability of the dried body containing cellulose nanofibers is not too high, the compressibility of the dried body 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. Furthermore, considering that the dried body containing cellulose nanofibers has good flowability and excellent feedability, excellent processability (specifically, it is not easy to generate scattering, floating or dust formation), good dispersion of the dried body containing cellulose nanofibers in the resin composition, and suppression of the transfer of dispersant to the resin, the compressibility is preferably 50% or less, or 45% or less, or 40% or less, or 35% or less, or 30% or less.

[0347] The loose bulk density, tapped density, and compressibility were measured using a powder tester (model: PT-X) manufactured by Hosokawa Micron Co., Ltd. The tapped density was measured by tapping 180 times.

[0348] As a more specific example of the process sequence, taking the case of using acid-modified styrene-based elastomers as an example, the following example can be given.

[0349] (i) Preparation of a slurry comprising cellulose nanofibers and optionally a liquid polymer and / or dispersant → drying to prepare a dried body → preparation of a preliminary composition comprising the dried body and an acid-modified styrene-based elastomer → preparation of a resin composition comprising the preliminary composition and the styrene-based elastomer

[0350] (ii) Preparation of a slurry comprising cellulose nanofibers and optionally a liquid polymer and / or dispersant → drying to prepare a dried body → preparation of a preliminary composition comprising the dried body, an acid-modified styrene-based elastomer, and a styrene-based elastomer → preparation of a resin composition comprising the preliminary composition and the styrene-based elastomer

[0351] (iii) Preparation of a slurry comprising cellulose nanofibers, an acid-modified styrene-based elastomer, and optionally a liquid polymer and / or dispersant → drying to prepare a dried body → preparation of a resin composition comprising the dried body and the styrene-based elastomer.

[0352] (iv) Preparation of a slurry comprising cellulose nanofibers, acid-modified styrene elastomers, styrene elastomers, and optionally a liquid polymer and / or dispersant → drying to prepare a resin composition.

[0353] Another example of using adhesive inhibitors containing cellulose nanofibers is as follows.

[0354] (i) Preparation of a slurry comprising cellulose nanofibers and optionally a liquid polymer and / or dispersant → drying to prepare a dried body → preparation of a preliminary composition comprising the dried body and an acid-modified styrene-based elastomer → preparation of a resin composition comprising the preliminary composition and the styrene-based elastomer

[0355] (ii) Preparation of a slurry comprising cellulose nanofibers and optionally a liquid polymer and / or dispersant → drying to prepare a dried body → preparation of a preliminary composition comprising the dried body, an acid-modified styrene-based elastomer, and a styrene-based elastomer → preparation of a resin composition comprising the preliminary composition and the styrene-based elastomer

[0356] (iii) Preparation of a slurry comprising cellulose nanofibers and optionally a liquid polymer and / or dispersant → drying to prepare a dried body → preparation of a resin composition comprising the dried body, an acid-modified styrene-based elastomer, and a styrene-based elastomer.

[0357] (iv) Preparation of a slurry comprising cellulose nanofibers, an acid-modified styrene-based elastomer, and optionally a liquid polymer and / or dispersant → drying to prepare a dried body → preparation of a resin composition comprising the dried body and the styrene-based elastomer.

[0358] (v) Preparation of a slurry comprising 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.

[0359] The desired molded article can be manufactured by molding the resin composition alone or together with other components into the desired shape. There are no particular limitations on the combination method of the compounding components and the molding method; they can be selected according to the desired molded article. Molding is usually melt molding and can be carried out through injection molding, extrusion molding, extrusion shaping, blow molding, compression molding, etc.

[0360] In one embodiment, the molding method can be a profile molding process. That is, in one embodiment, the resin molded article can be a profile molded article. Another embodiment of the present invention provides a method for manufacturing a profile extruded article, which includes a step of profile extruding the resin composition of this embodiment.

[0361] Shaped extrusion molding can be performed using known methods. A specific example of a shaped extrusion molding method is as follows: a resin composition is fed into an extrusion molding machine, heated and mixed inside, and extruded from a die for shape extrusion to obtain an uncooled resin molded body. Then, the uncooled resin molded body is continuously fed into a cooling zone for cooling to obtain a shaped extruded product.

[0362] Alternatively, the following method can be used: melt mixing is performed to obtain a resin composition, and the die head of the mixer is used as a die head for profile extrusion to obtain an uncooled resin molded body. Then, the uncooled resin molded body is continuously introduced into a cooling zone for cooling to obtain a profile extruded molded article.

[0363] Regarding the lower limit of the extrusion temperature during profile extrusion, when the thermoplastic resin in the resin composition is a crystalline resin, it is preferably +5°C, more preferably +10°C, relative to the melting point; or when it is an amorphous resin, relative to the glass transition temperature. By controlling the lower limit within this range, the productivity of profile extrusion can be improved. Regarding the upper limit of the extrusion temperature during profile extrusion, when the thermoplastic resin in the resin composition is a crystalline resin, it is preferably +100°C, more preferably +80°C, more preferably +70°C, more preferably +60°C, relative to the melting point; or when it is an amorphous resin, relative to the glass transition temperature. By controlling the upper limit within this range, the deterioration of cellulose microfibers can be suppressed, thus maintaining the mechanical properties of the resin composition. Furthermore, it suppresses resin dripping between the die and the cooling zone during profile extrusion, resulting in good dimensional accuracy of the profile extruded product.

[0364] As an irregularly shaped extruded product, there are no particular restrictions on the cross-sectional shape; however, sheet-like, tubular, flexible, and angular shapes are preferred. In the case of a sheet, the sheet thickness can range from 0.2 mm to 50 mm, and the sheet width can range from 10 mm to 1500 mm. In the case of a tubular or flexible shape, the thickness can range from 0.1 mm to 30 mm, and the inner diameter can range from 1 mm to 1000 mm. In the case of an angular shape, the angle of the corner can range from 30 degrees to 150 degrees. Furthermore, the minimum radius of curvature of the valley side of the corner can be 0.1 mm.

[0365] <Modeling Materials for 3D Printing>

[0366] A preferred example of the use of the resin composition of this embodiment is as a modeling material for 3D printing. One aspect of the present invention provides a modeling material for 3D printing composed of the resin composition of this embodiment. The modeling material for 3D printing can be molded into a desired form selected from various forms such as granules, filaments, and powders. In one aspect, the modeling material for 3D printing has the form of filaments or powder.

[0367] The 3D printing molding material of this embodiment utilizes the aggregation inhibition ability of cellulose nanofibers, which is advantageous in suppressing liquid dripping (droplets) caused by the weight of the nozzle during molding.

[0368] As a method for molding a resin composition into a desired shape for 3D printing, known methods can be used. For example, the filament can be either a monofilament or a multifilament; from the perspective of ease of molding, a monofilament is preferred.

[0369] The diameter of the filamentous modeling material is preferably 0.5 mm to 5.0 mm, more preferably 1.0 mm to 3.5 mm, and most preferably 1.5 mm to 3.0 mm. The length of the filamentous modeling material is preferably more than 1 m, more preferably more than 10 m, more preferably more than 100 m, and most preferably more than 300 m. By controlling the shape of the filamentous modeling material within this range, a wide range of suitable 3D printers can be selected, and the modeling time, size, and sophistication of the model can be appropriately designed. In one embodiment, the length of the filamentous modeling material can be less than 20,000 m.

[0370] In one method, the filamentous molding material can be manufactured by heating and melting a resin composition, then passing it through a fine orifice such as a nozzle, cooling it, and winding it up. The diameter of the fine orifice can be appropriately selected according to the diameter of the filament and the winding speed. From the perspective of manufacturing efficiency and the frequency of filament breakage, it is preferably 0.5 mm to 10.0 mm, more preferably 0.8 mm to 5.0 mm, and most preferably 1.0 mm to 3.0 mm. As for the cooling method, known methods such as air cooling and water cooling can be appropriately selected. From the perspective of preventing water absorption caused by the hydrophilicity of cellulose nanofibers, air cooling is preferred. From the perspective of manufacturing efficiency and the frequency of filament breakage, the winding speed of the filament is preferably 0.1 m / s to 10 m / s, more preferably 0.15 m / s to 5 m / s, and most preferably 0.2 m / s to 1 m / s. The apparatus for manufacturing the filamentous molding material and the apparatus for manufacturing the resin composition can be the same or different.

[0371] The particle size, particle shape, and aspect ratio of the powder-like molding material can be appropriately selected according to the 3D printer used. In one embodiment, from the perspective of processing as a molding material and the surface smoothness of the molded object, the particle size is preferably 1 μm to 10000 μm, more preferably 10 μm to 500 μm, and most preferably 30 μm to 200 μm. The particle shape can be spherical or amorphous, and from the perspective of suppressing voids during molding, amorphous is preferred. From the perspective of suppressing voids by reducing particle gaps, the aspect ratio is preferably 1.001 to 3.0, more preferably 1.01 to 2.0, and most preferably 1.1 to 1.8.

[0372] In one approach, powdered molding materials can be manufactured by pulverizing or reprecipitating a resin composition. There are no particular limitations on the method of pulverizing the resin composition; it can include wet pulverization, dry pulverization, cryogenic pulverization, cryogenic pulverization, and thermo-pulverization. Pulverizing media can also be used for the purpose of controlling the shape of the powdered molding material.

[0373] <Artwork>

[0374] One aspect of the present invention provides a shaped object formed by molding the resin composition (e.g., resin composition granules) or 3D printing molding material of this embodiment using a 3D printer. Another aspect of the present invention provides a method for manufacturing the shaped object, comprising a step of molding the resin composition or 3D printing molding material of this embodiment using a 3D printer. Examples of molding methods using a 3D printer include thermal delamination, photolithography, material jetting, powder bonding, and powder bed fusion bonding. When using filamentous molding materials, thermal delamination is preferred; when using powder-like molding materials, powder bonding and powder bed fusion bonding are preferred.

[0375] <Applications of 3D Printing Modeling Materials and Models>

[0376] The model can be applied directly to various applications, or it can be molded into a desired shape, either alone or together with other components, to manufacture a desired molded article. There are no particular limitations on the combination of components or the molding method; the choice depends on the desired molded article. Molding methods include, but are not limited to, cutting molding and foam molding. The model or molded article is useful as a substitute for steel sheets, fiber-reinforced plastics (e.g., carbon fiber reinforced plastics, glass fiber reinforced plastics, etc.), resin composites containing inorganic fillers, etc. Preferred applications for 3D printing modeling materials, models, or molded articles include industrial machinery parts, general machinery parts, automotive / railway / vehicle / ship / aerospace related parts, electronic / electrical parts, building / civil engineering materials, consumer goods, sports / leisure products, wind power generation shell components, container / packaging components, etc.

[0377] The resulting molded products can be used for various purposes, including automotive parts, electrical / electronic parts, building materials, household / decorative / medical parts, tracks, pipes, frames, door frames, window frames, handrails, deck materials, fences, and various other building materials.

[0378] Specifically, automotive components include interior handles, fuel tank openers, seatbelt buckles, auxiliary handles, various switches, knobs, handles, clips, and other interior parts; electrical system components such as instruments and connectors; vehicle electrical / electronic components such as audio equipment and car navigation equipment; metal-contact components such as window regulator trays; door lock actuator components; reflector components; wiper motor system components; and fuel system components.

[0379] As electrical / electronic components, examples include parts or components of equipment made of resin molding and having multiple metal contacts, such as audio equipment, video equipment, or OA equipment such as telephones, copiers, fax machines, word processors, and computers, as well as parts or components of toys. Specifically, examples include chassis, gears, handles, cams, pulleys, and bearings.

[0380] Furthermore, it is suitable for a wide range of everyday / cosmetic / medical related components, including lighting fixtures, door and window hardware, piping, stopcocks, faucets, toilet peripheral equipment components, zippers, stationery, lipstick / lip gloss containers, cleaners, water purifiers, spray nozzles, spray containers, aerosol containers, general containers, and injection needle holders.

[0381] Among these, gears are preferred for applications involving high-temperature environments and high loads.

[0382] The tensile stress (modulus) (M100) at 100% elongation of the resin composition or resin molded article may be 2.0 MPa or more, or 3.0 MPa or more, or 4.0 MPa or more, or 10.0 MPa or less, or 9.0 MPa or less, or 8.0 MPa or less in one embodiment.

[0383] The tensile stress (M300) at 300% elongation of the resin composition or resin molded article may be 3.0 MPa or more, 5.0 MPa or more, or 6.0 MPa or more in one embodiment, and 20.0 MPa or less, 15.0 MPa or less, or 13.0 MPa or less in another embodiment.

[0384] The ratio (M300 / M100) of the tensile stress at 300% elongation to the tensile stress at 100% elongation of the resin composition or resin molded article may be 1.3 or more, or 1.4 or more, or 1.5 or more in one embodiment, and 2.0 or less, or 1.8 or less in another embodiment.

[0385] The storage modulus of the resin composition or the resin molded article may be 2.0 MPa or more, or 2.5 MPa or more, or 4.0 MPa or less, or 3.5 MPa or less, or 3.0 MPa or less, in one embodiment.

[0386] The loss tangent of the resin composition or resin molded article may be less than 0.18, less than 0.15, or less than 0.10 in one embodiment, and more than 0.02, more than 0.03, or more than 0.04 in another embodiment.

[0387] The above-mentioned energy storage modulus and loss tangent were measured using a rheometer under torsional conditions at 50°C and 10Hz.

[0388] Resin Molded Body

[0389] One aspect of the present invention provides a resin molded body formed by molding the resin composition of this embodiment. The resin molded body can have various shapes. The molded body can be used in a wide range of applications, including industrial machinery parts, general machinery parts, automotive / railway / vehicle / ship / aerospace related parts, electronic / electrical parts, building / civil engineering materials, consumer goods, sports / leisure products, wind power generation shell components, container / packaging components, and more. As examples of applications, it can be formed into automotive parts (e.g., tires, bumpers, mudguards, door panels, various trim strips, car logos, engine hoods, wheel covers, roofs, spoilers, various aerodynamic kits and other exterior parts, as well as dashboards, console boxes, decorative parts and other interior parts), battery parts (on-board secondary battery parts, lithium-ion secondary battery parts, fuel housings for solid methanol batteries, piping for fuel cells, etc.), electronic / electrical equipment parts (e.g., various computers and their peripherals, junction boxes, various connectors, various OA equipment, televisions, video recorders, CD players, chassis, refrigerators, air conditioners, LCD projectors and other parts), daily necessities (shoe outsoles, etc.), vibration damping rubber, conveyor belts and other molded products.

[0390] This disclosure includes the following items.

[0391] Project A

[0392] [Project 1]

[0393] A resin composition comprising an acid-modified styrene elastomer, a styrene elastomer, and cellulose nanofibers, wherein, In the above resin composition, the total amount of the above acid-modified styrene elastomer and the above styrene elastomer is 60% by mass or more in 100% by mass.

[0394] [Project 2]

[0395] According to the resin composition of Project 1, the acid-modified styrene elastomer and the styrene elastomer are compatible.

[0396] [Project 3]

[0397] The resin composition according to item 1 or 2, wherein, relative to 100 parts by weight of the above-mentioned styrene-based elastomer, comprises 0.5 to 50 parts by weight of the above-mentioned acid-modified styrene-based elastomer.

[0398] [Project 4]

[0399] The resin composition according to any one of items 1 to 3, wherein, relative to 1 part by weight of the above-mentioned cellulose nanofibers, comprises 0.5 parts by weight to 250 parts by weight of the above-mentioned styrene-based elastomer.

[0400] [Project 5]

[0401] The resin composition according to any one of items 1 to 4, wherein, relative to 1 part by weight of the above-mentioned cellulose nanofibers, comprises 0.5 to 45 parts by weight of the above-mentioned acid-modified styrene elastomer.

[0402] [Project 6]

[0403] The resin composition according to any one of items 1 to 5 comprises 0.5% to 50% by mass of the above-mentioned acid-modified styrene elastomer.

[0404] [Project 7]

[0405] The resin composition according to any one of items 1 to 6 comprises 10% to 98.8% by mass of the above-mentioned styrene-based elastomer.

[0406] [Project 8]

[0407] The resin composition according to any one of items 1 to 7 comprises 0.1% to 20% by mass of the above-mentioned cellulose nanofibers.

[0408] [Project 9]

[0409] The resin composition according to any one of items 1 to 8, wherein the acid modification rate of the above-mentioned acid-modified styrene elastomer is 0.2% to 2.5% by mass.

[0410] [Project 10]

[0411] The resin composition according to any one of items 1 to 9, wherein the styrene-based elastomer is an unmodified product.

[0412] [Project 11]

[0413] The resin composition according to any one of items 1 to 10, wherein the acid-modified styrene elastomer is an acid-modified styrene elastomer that is an aromatic vinyl compound-conjugated diene compound block copolymer or its hydrogenated form.

[0414] [Project 12]

[0415] 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 hydrogenation thereof.

[0416] [Project 13]

[0417] The resin composition according to any one of items 1 to 12, wherein the styrene-based elastomer has a melt flow rate of less than 20 g / 10 minutes under conditions of 230°C and 2.16 kg.

[0418] [Project 14]

[0419] The resin composition according to any one of items 1 to 13, wherein the proportion of styrene units in the above-mentioned acid-modified styrene elastomer is 10% to 45% by mass.

[0420] [Project 15]

[0421] The resin composition according to any one of items 1 to 14, wherein the styrene unit proportion of the above-mentioned styrene-based elastomer is 10% to 45% by mass.

[0422] [Project 16]

[0423] The resin composition according to any one of items 1 to 15, wherein the ratio of the styrene unit proportion of the styrene elastomer to the styrene unit proportion of the acid-modified styrene elastomer (styrene proportion of styrene elastomer / styrene proportion of acid-modified styrene elastomer) is 0.3 to 2.5.

[0424] [Project 17]

[0425] The resin composition according to any one of items 1 to 16, wherein the number average molecular weight of the acid-modified styrene elastomer is 10,000 to 500,000, and the number average molecular weight of the styrene elastomer is 10,000 to 500,000.

[0426] [Project 18]

[0427] The resin composition according to any one of items 1 to 17, wherein, in the above-mentioned acid-modified styrene elastomer, the ratio of styrene unit proportion to acid modification rate (styrene unit proportion / acid modification rate) is 5 to 90.

[0428] [Project 19]

[0429] The resin composition according to any one of items 1 to 18, wherein, relative to 100% by mass of the above-mentioned cellulose nanofibers, the amount of acid-modifying group of the above-mentioned acid-modified styrene elastomer is 0.2% to 5.0% by mass.

[0430] [Project 20]

[0431] The resin composition according to any one of items 1 to 19, wherein the number-average fiber diameter of the cellulose nanofibers is 2 nm to 1000 nm.

[0432] [Project 21]

[0433] The resin composition according to any one of items 1 to 20, wherein the thermal decomposition initiation temperature of the cellulose nanofibers is above 250°C.

[0434] [Project 22]

[0435] The resin composition according to any one of items 1 to 21, wherein the specific surface area of ​​the cellulose nanofibers is 10 m². 2 / g~200m 2 / g.

[0436] [Project 23]

[0437] The resin composition according to any one of items 1 to 22 further comprises a polymer containing polyoxyethylene units.

[0438] [Project 24]

[0439] The resin composition according to any one of items 1 to 23 further comprises a liquid polymer.

[0440] [Project 25]

[0441] A method for manufacturing the resin composition described in any one of items 1 to 24, wherein, The above method includes the following steps: heating and kneading a mixture comprising the above-mentioned acid-modified styrene elastomer, the above-mentioned styrene elastomer and the above-mentioned cellulose nanofibers.

[0442] [Project 26]

[0443] A resin molded body is formed by molding the resin composition described in any one of items 1 to 24.

[0444] [Project 27]

[0445] The resin molded article described in Project 26 is a profiled extruded product.

[0446] [Project 28]

[0447] One method is a method for manufacturing irregularly shaped extruded articles, wherein, The above method includes a step of extruding the resin composition described in any one of items 1 to 24 in a profile.

[0448] [Project 29]

[0449] A modeling material for 3D printing, comprising any one of the resin compositions described in items 1 to 24.

[0450] [Project 30]

[0451] According to Project 29, the 3D printing modeling material has the form of filaments or powder.

[0452] [Project 31]

[0453] A modeling object is formed by using a 3D printer to shape the resin composition described in any one of items 1 to 24 or the 3D printing modeling material described in item 29 or 30.

[0454] [Project 32]

[0455] One method is a method for manufacturing shaped objects, in which... The above method includes a step of using a 3D printer to shape the resin composition described in any one of items 1 to 24 or the 3D printing modeling material described in item 29 or 30.

[0456] Project B

[0457] [Project 1]

[0458] A resin composition comprising a styrene-based elastomer and a viscosity inhibitor containing cellulose nanofibers.

[0459] [Project 2]

[0460] The resin composition according to Project 1 contains more than 10% by mass of the above-mentioned styrene-based elastomer.

[0461] [Project 3]

[0462] The resin composition according to item 1 or 2 comprises 0.1% to 20% by mass of the above-mentioned cellulose nanofibers.

[0463] [Project 4]

[0464] The resin composition according to any one of items 1 to 3 further comprises an acid-modified styrene-based elastomer.

[0465] [Project 5]

[0466] The resin composition according to any one of items 1 to 4, wherein the styrene-based elastomer is an unmodified product.

[0467] [Project 6]

[0468] The resin composition according to any one of items 1 to 5, wherein, relative to 1 part by weight of the cellulose nanofibers, comprises 0.5 parts by weight to 250 parts by weight of the styrene-based elastomer.

[0469] [Project 7]

[0470] 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 its hydrogenation.

[0471] [Project 8]

[0472] The resin composition according to any one of items 1 to 7, wherein the MFR of the above-mentioned styrene-based elastomer is less than 20 g / 10 minutes under the conditions of 230°C and 2.16 kg.

[0473] [Project 9]

[0474] The resin composition according to any one of items 1 to 8, wherein the styrene unit proportion of the above-mentioned styrene elastomer is 10 mol% to 40 mol%.

[0475] [Project 10]

[0476] The resin composition according to any one of items 1 to 9, wherein the number average molecular weight of the styrene-based elastomer is 10,000 to 500,000.

[0477] [Project 11]

[0478] 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.

[0479] [Project 12]

[0480] The resin composition according to any one of items 1 to 11, wherein the thermal decomposition initiation temperature of the cellulose nanofibers is above 250°C.

[0481] [Project 13]

[0482] The resin composition according to any one of items 1 to 12, wherein the specific surface area of ​​the cellulose nanofibers is 10 m². 2 / g~200m 2 / g.

[0483] [Project 14]

[0484] The resin composition according to any one of items 1 to 13 further comprises a dispersant.

[0485] [Project 15]

[0486] According to the resin composition of Project 14, wherein the dispersant is a polymer containing polyoxyethylene units.

[0487] [Project 16]

[0488] The resin composition according to any one of items 1 to 15 further comprises a liquid polymer.

[0489] [Project 17]

[0490] A method for manufacturing the resin composition described in any one of items 1 to 16, wherein, The above method includes the following steps: a mixing process of heating and mixing a mixture containing styrene-based elastomers and cellulose nanofibers.

[0491] [Project 18]

[0492] According to the method described in Project 17, the cellulose nanofibers supplied to the above-mentioned mixing process are a dry body with a liquid medium content of less than 7% by mass.

[0493] [Project 19]

[0494] A resin molded body is formed by molding the resin composition described in any one of items 1 to 16.

[0495] [Project 20]

[0496] The resin molded article described in Project 19 is a shaped extruded molded article.

[0497] [Project 21]

[0498] One method is a method for manufacturing irregularly shaped extruded articles, wherein, The above method includes a step of extruding the resin composition described in any one of items 1 to 16 in a profile.

[0499] [Project 22]

[0500] A modeling material for 3D printing, comprising any one of the resin compositions described in items 1 to 16.

[0501] [Project 23]

[0502] According to Project 22, the 3D printing modeling material has the form of filaments or powder.

[0503] [Project 24]

[0504] A modeling object is formed by using a 3D printer to shape the resin composition described in any one of items 1 to 16 or the 3D printing modeling material described in item 22 or 23.

[0505] [Project 25]

[0506] One method is a method for manufacturing shaped objects, in which... The above method includes a step of using a 3D printer to shape the resin composition described in any one of items 1 to 16 or the 3D printing modeling material described in item 22 or 23.

[0507] Example

[0508] The following examples further illustrate the illustrative aspects of the present invention, but the present invention is not limited to these examples in any way.

[0509] Evaluation Methods

[0510] <Acid-Modified Styrene-Based Elastomers and Styrene-Based Elastomers>

[0511] [Acid Modification Rate (Malaysia Acidification Rate)]

[0512] Show the values ​​in the product catalog.

[0513] [Styrene Unit Ratio]

[0514] Show the values ​​in the product catalog.

[0515] [MFR at 230℃ and 2.16kg]

[0516] Show the values ​​in the product catalog.

[0517] Liquid polymers

[0518] [Viscosity at 25℃]

[0519] The viscosity of the rubber was measured using a type B viscometer.

[0520] Cellulose nanofibers

[0521] The following evaluation was performed on the cellulose nanofibers.

[0522] [Preparation of porous sheets]

[0523] First, the concentrated filter cake was added to tert-butanol and further dispersed using a mixer until no agglomerates remained. The concentration was adjusted to 0.5% by mass relative to 0.5g of the cellulose nanofiber solids. 100g of the resulting tert-butanol dispersion was filtered onto filter paper. The filter cake was not peeled off the filter paper but sandwiched between two larger sheets of filter paper, with the edges of the larger sheets held down by a weight, and then dried in an oven at 150°C for 5 minutes. Afterward, the filter paper was peeled off, yielding a porous sheet with minimal deformation. The air permeability resistance of this sheet was measured relative to 10g / m³. 2 Slides with a substrate weight of less than 100 sec / 100 ml are used as porous slides for the determination of samples.

[0524] The basis weight W (g / m³) of the sample was determined after standing for one day at 23℃ and 50%RH. 2 Afterwards, the air permeability resistance R (sec / 100ml) was measured using a Wang Yan-type air permeability resistance testing machine (manufactured by Asahi Seiko Co., Ltd., model EG01). At this point, the air permeability resistance per 10g / m³ was calculated using the following formula. 2 The value of the basis weight.

[0525] per 10g / m 2 Air permeability resistance per unit weight (sec / 100ml) = R / W × 10

[0526] [Weight-average molecular weight (Mw), number-average molecular weight (Mn), and Mw / Mn ratio]

[0527] Weigh 0.88 g of porous nanofiber sheet, cut it into small pieces with scissors, stir gently, then add 20 mL of pure water and let stand for 1 day. Next, separate the water and solid components by centrifugation. Then add 20 mL of acetone, stir gently, and let stand for 1 day. Next, separate the acetone and solid components by centrifugation. Next, add 20 mL of N,N-dimethylacetamide, stir gently, and let stand for 1 day. Separate the N,N-dimethylacetamide and solid components again by centrifugation, then add another 20 mL of N,N-dimethylacetamide, stir gently, and let stand for 1 day. Separate the N,N-dimethylacetamide and solid components by centrifugation, add 19.2 g of N,N-dimethylacetamide solution prepared according to the method of lithium chloride at 8% by mass to the solid components, stir with a stirrer, and visually confirm dissolution. Filter the solution containing dissolved cellulose nanofibers through a 0.45 μm filter, and use the filtrate as the sample for gel permeation chromatography. The apparatus and determination conditions used are described below.

[0528] Device: Tosoh HLC-8120

[0529] Columns: 2 TSKgel SuperAWM-H (6.0mm I.D. × 15cm)

[0530] Detector: RI detector

[0531] Eluent: N,N-dimethylacetamide (lithium chloride 0.2%)

[0532] Flow rate: 0.6 mL / min

[0533] Correction curve: Pullulan conversion

[0534] [Average content of alkali-soluble polysaccharides]

[0535] Regarding the content of alkali-soluble polysaccharides, for cellulose nanofibers, the method described in non-patent literature (Handbook of Wood Science Experiments, edited by Japan Wood Society, pp. 92-97, 2000) is used, by subtracting the α-cellulose content from the total cellulose content (Wise method). The alkali-soluble polysaccharide content is calculated three times for each sample, and the mean of the calculated alkali-soluble polysaccharide content is taken as the average alkali-soluble polysaccharide content of the cellulose nanofibers.

[0536] [Average content of acid-insoluble components]

[0537] For the quantification of acid-insoluble components, cellulose nanofibers were analyzed using the Clason method described in non-patent literature (Handbook of Wood Science Experiments, edited by the Japan Wood Science Society, pp. 92-97, 2000). Absolutely dried cellulose nanofibers were precisely weighed and placed in a designated container. 72% (w / w) concentrated sulfuric acid was added, and the mixture was gently pressed with a glass rod to ensure homogeneity. Then, cellulose and hemicellulose were dissolved in the acid solution using an autoclave. After natural cooling, the contents were filtered through glass fiber filter paper, yielding the acid-insoluble components as residue. The content of the acid-insoluble components was calculated from their weight. The mean of the calculated contents from three samples was then taken as the average content of the acid-insoluble components.

[0538] [Crystallization degree]

[0539] X-ray diffraction of the porous sheet was performed, and the crystallinity was calculated using the following formula.

[0540] Crystallinity (%) = [I (200) -I (amorphous) ] / I (200) ×100

[0541] I (200) Intensity of diffraction peaks on the 200 plane (2θ = 22.5°) in type I cellulose crystals.

[0542] I (amorphous) The peak intensity of the amorphous halo in type I cellulose crystals is the peak intensity at an angle 4.5° lower than the diffraction angle of the 200 plane (2θ = 18.0°).

[0543] (X-ray diffraction measurement conditions)

[0544] Device MiniFlex (manufactured by Rigaku Co., Ltd.)

[0545] Operating axis 2θ / θ

[0546] X-ray source CuKα

[0547] Measurement method continuous

[0548] 40kV

[0549] 15mA current

[0550] Starting angle 2θ = 5°

[0551] Termination angle 2θ = 30°

[0552] Sampling width 0.020°

[0553] Scanning speed 2.0° / min

[0554] Sample: A porous sheet was attached to the sample holder.

[0555] [Number Average Fiber Diameter]

[0556] The concentrated filter cake was diluted to 0.01% by mass with tert-butanol and dispersed using a high-shear homogenizer (IKA, trade name "ULTRA-TURRAX T18") at 15,000 rpm for 3 minutes. The dispersed material was then poured onto an osmium-deposited silicon substrate and air-dried. The resulting material was measured using a high-resolution scanning electron microscope (Hitachi High Technology Co., Ltd., Regulus 8220). The magnification was adjusted to ensure at least 100 cellulose nanofibers were observed. The diameter (D) of 100 randomly selected cellulose nanofibers was measured, and the arithmetic mean of the 100 nanofibers was calculated as the number-average fiber diameter.

[0557] Aspect Ratio

[0558] 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 were determined using an optical microscope according to the following steps. The resin composition, prepared by heating and mixing resin and cellulose nanofibers, was used as the test sample. The cellulose nanofibers in the resin were measured using an optical microscope while the mixture was heated to 220°C. Specifically, the length and diameter of 200 randomly selected cellulose nanofibers were measured, and the ratio was calculated. Then, the number average values ​​were used as the number-average fiber length (L) and number-average fiber diameter (D), and the number-average aspect ratio (L / D) was calculated.

[0559] [Specific surface area]

[0560] Approximately 0.2 g of porous sheet was dried under vacuum at 120 °C for 5 hours using a surface area and pore size distribution measuring apparatus (Nova-4200e, Quantachrome Instruments). Then, the amount of nitrogen adsorbed at the boiling point of liquid nitrogen was measured at five points (multi-point method) within a relative vapor pressure (P / P0) range of 0.05 to 0.2. Subsequently, the BET surface area (m²) was calculated using the same apparatus procedure. 2 / g).

[0561] Thermal decomposition initiation temperature (T) D )]

[0562] Thermal analysis of porous sheets was performed using the following measurement method.

[0563] Device: Rigaku Corporation, Thermo plus EVO2

[0564] Samples: The samples obtained by cutting the porous sheet into circles are stacked in an aluminum sample tray at a rate of 10 mg.

[0565] Sample amount: 10mg

[0566] Measurement conditions: Under nitrogen flow of 100 ml / min, the temperature was increased from room temperature to 150℃ at a rate of 10℃ / min, held at 150℃ for 1 hour, and then directly increased to 450℃ at a rate of 10℃ / min.

[0567] T D Calculation method: The temperature is plotted on the horizontal axis and the weight residual percentage (%) on the vertical axis. Starting with the weight of the porous sheet at 150℃ (when moisture is approximately removed) (weight loss of 0 wt%), the temperature is further increased to obtain straight lines at the temperatures of 1 wt% and 2 wt% weight loss. The temperature at the intersection of this straight line and the horizontal line (baseline) at the 0 wt% weight loss point is taken as the thermal decomposition initiation temperature (T). D ).

[0568] [1wt% weight reduction in temperature]

[0569] The above T D The temperature at which 1 wt% weight loss occurs is used in the calculation as the 1 wt% weight loss temperature.

[0570] [Weight loss rate at 250℃]

[0571] Device: Rigaku Corporation, Thermo plus EVO2

[0572] Samples: The samples obtained by cutting the porous sheet into circles are stacked in an aluminum sample tray at a rate of 10 mg.

[0573] Sample amount: 10mg

[0574] Measurement conditions: Under nitrogen flow of 100 ml / min, the temperature was increased from room temperature to 150°C at a rate of 10°C / min, held at 150°C for 1 hour, then increased from 150°C to 250°C at a rate of 10°C / min, and held directly at 250°C for 2 hours. The weight W0 at the moment 250°C was reached was taken as the starting point, and the weight after holding at 250°C for 2 hours was taken as W1, calculated using the following formula.

[0575] Weight change rate at 250℃ (%): (W0-W1) / W0×100

[0576] [Weight gain rate of cellulose nanofibers isolated from resin composition using THF]

[0577] Those skilled in the art can easily separate cellulose nanofibers from resin compositions using conventional methods. The separation is performed using the following method: Using approximately 1.5 g of a fragment of the resin composition, the fragment is dissolved in 70 ml of THF, separating it into soluble components (resin) and insoluble components (cellulose nanofibers and resin adsorbed on the fiber surface). The insoluble components are filtered through filter paper and then concentrated by drying in a vacuum dryer at 80°C for 3 hours. The weight of the insoluble components is then measured. The weight gain rate of the cellulose nanofibers is calculated using the following formula. It should be noted that the theoretical weights described below refer to the initial feed weight of the cellulose nanofibers.

[0578] Weight gain rate of cellulose nanofibers (%) = (Weight of insoluble component - Theoretical weight of cellulose nanofibers contained in the fracture fragment) ÷ Theoretical weight of cellulose nanofibers contained in the fracture fragment × 100

[0579] <Resin Composition>

[0580] [Degree of whitening at fracture (porosity)]

[0581] The test specimens tested according to the tensile test method of JIS K-6251 were examined by X-ray CT to observe the cross section in the MD / TD direction of the fracture site (ND direction 2×TD direction 3×MD direction 4mm).

[0582] Device: Bruker X-CT Skyscan 1272

[0583] <Conditions>

[0584] Tube voltage: 40kV, tube current: 100μA, number of pixels: 2k (2452×1640 pix), pixel resolution: 2.4μm, number of integrations: 4, scan rate: every 0.4°, analysis processing: smoothing (Kuwahara filter 2pixel).

[0585] Next, the observed image is binarized to extract the gaps and the percentage of the total volume of the gaps per unit volume is numerically represented.

[0586] (Binarization conditions for void regions)

[0587] Binarize to 0-35 (global range: 0-255); remove targets smaller than 4 voxels; for targets larger than 50 pixels in the xy section, treat them as foreign objects or artifacts from foreign objects and remove them.

[0588] (Evaluation Criteria)

[0589] Unsatisfactory: 1% or more

[0590] Pass: 0.5% or higher and less than 1%

[0591] Good: Above 0.02% and below 0.5%

[0592] Excellent: Less than 0.02%

[0593] [Tensile stress at 400% strain, tensile modulus of elasticity at 50%–100% strain, maximum tensile stress, strain]

[0594] 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 determined using the tensile test method of JIS K-6251. The tensile stress at 400% strain, the tensile elastic modulus at 50%–100% strain (the value obtained by dividing the increment of 100% modulus relative to 50% modulus by the increase in strain (100%–50%)), the maximum tensile stress, and the strain at fracture were calculated.

[0595] [Coloring properties]

[0596] Visually evaluate the color of the shaped dumbbells.

[0597] (Evaluation Criteria)

[0598] Defect: Caramel color

[0599] Acceptable: Light caramel color

[0600] Good: Milky white

[0601] Advantages: White or transparent

[0602] [Surface roughness of the thread]

[0603] Visually evaluate the surface condition of the extruded filament.

[0604] (Evaluation Criteria)

[0605] Defect: Surface condition with severe unevenness and lack of smooth sections.

[0606] Acceptable: A surface condition in which smooth parts and uneven surfaces exist in equal proportions.

[0607] Good: Some surface roughness was observed.

[0608] Excellent: Surface condition with absolutely no fuzzy areas.

[0609] [viscosity]

[0610] The viscous strength was determined using a Rhesca TAC-II viscous testing machine. The test mode used was constant load, which continuously controls the pressure applied to the probe to the set pressure value and maintains that pressure for a set time.

[0611] Specifically, for a surface area of ​​19.625 mm 2 A flat stainless steel probe was used. Under the conditions of probe movement speed: 120 mm / min, applied pressure (load): 600 gf, and applied pressure time: 60 seconds, the flat surface of the stainless steel probe was brought into contact with the surface of the test sample. The peak viscosity of the resin composition surface, based on the probe viscosity test, was measured 10 times when peeling upwards at a probe movement speed (separation speed): 600 mm / min. The average of the 10 measurements was divided by the area of ​​the flat probe surface, and the resulting value was taken as the viscous strength. The measurement was performed at 23°C.

[0612] [Tensile stress at 400% strain, maximum tensile stress, strain]

[0613] Tensile tests were conducted using ISO 37 type 3 test specimens at an environment of 23°C and 50% relative humidity at a tensile speed of 5 mm / min. The arithmetic mean of five data points was calculated: tensile stress at 400% strain, maximum tensile stress, and strain at fracture.

[0614] Materials Used

[0615] <Styrene-based elastomers>

[0616] SEBS, Tuftec H1062 manufactured by Asahi Kasei Co., Ltd., MFR: 4.1g / 10min (230℃·2.16kg)

[0617] <Acid-modified styrene-based elastomers>

[0618] Acid-modified styrene-based elastomer 1: Maleic acid modified SEBS, manufactured by Asahi Kasei Corporation, Tuftec M1943, MFR: 6.5g / 10min (230℃·2.16kg)

[0619] Acid-modified styrene-based elastomer 2: Maleic acid modified SEBS, manufactured by Asahi Kasei Corporation, Tuftec M1913, MFR: 6.5g / 10min (230℃·2.16kg)

[0620] Acid-modified styrene-based elastomer 3: Maleic acid modified SEBS, manufactured by Asahi Kasei Corporation, Tuftec M1911, MFR: 4.2g / 10min (230℃·2.16kg)

[0621] Cellulose nanofibers (unmodified CNF)

[0622] Three parts by weight of cotton lint pulp were impregnated in 27 parts by weight of water and dispersed using a pulper. 170 parts by weight of water were added to 30 parts by weight of the pulped cotton lint pulp (containing 3 parts by weight of cotton lint pulp) to disperse it in water (solid content 1.5% by weight). The dispersion was then beating for 30 minutes using an Aikawa Iron Works SDR14 LabRefiner (pressure type DISK) as a disc refiner with a disc gap of 1 mm. Subsequently, the dispersion was thoroughly beating at a gap level approaching zero to obtain a beaten aqueous dispersion (solid content concentration: 1.5% by weight). The obtained beaten aqueous dispersion was then directly subjected to a high-pressure homogenizer (Niro Soavi (Italy) NSO15H) at an operating pressure of 100 MPa for 10 micronization processes to obtain a cellulose nanofiber pulp (solid content concentration: 1.5% by weight). The mixture was then concentrated using a dehydrator to a solid content of 10% by mass, yielding a filter cake of cellulose nanofibers. The properties of the cellulose nanofibers are as follows.

[0623] Weight-average molecular weight (Mw): 380,000

[0624] Number average molecular weight (Mn): 80,000

[0625] Average content of alkali-soluble polysaccharides: 3.8%

[0626] Average content of acid-insoluble components: 3.1%

[0627] Crystallinity: 85%

[0628] Number average fiber diameter: 75nm

[0629] Specific surface area: 34m² 2 / g

[0630] Thermal decomposition initiation temperature (T) D ): 283℃

[0631] 1wt% weight loss temperature: 297℃

[0632] Weight loss rate at 250℃: 2.8%

[0633] <Dispersant>

[0634] Polyethylene glycol: PEG6000, manufactured by Sanyo Chemical Co., Ltd.

[0635] Liquid polymers

[0636] Liquid polybutadiene: manufactured by Cray Valley, RICON 184, viscosity at 25°C: 75000 mPa·s

[0637] Manufacturing of Resin Compositions

[0638] <Example 1>

[0639] Cellulose nanofiber filter cake, RICON 184, and PEG6000 were mixed in a solids weight ratio of 7:4:3. The mixture was stirred using a planetary mixer (model: ACM-5LVT: paddle type) manufactured by Kodaira Co., Ltd., at a jacket temperature of 80°C and 307 rpm, while simultaneously reducing the pressure to -90 kPa using a vacuum pump. The mixture was then dried under reduced pressure until the product temperature reached 70°C to obtain cellulose nanofiber powder. The obtained cellulose nanofiber powder, SEBS, and acid-modified styrene elastomer 1 were mixed in the proportions shown in Table 1. The mixture was melted for 5 minutes at 200°C and 200 rpm using an intermittent twin-screw extruder (DSM Explore). Test pieces (ISO 37 type 3) were then produced using a dedicated benchtop injection molding machine (DSM) at a mold temperature of 80°C.

[0640] <Examples 2-11, Comparative Examples 1-3>

[0641] Except for the changes in proportions as described in Table 1, the resin composition was obtained in the same manner as in Example 1.

[0642] [Table 1]

[0643] Industrial applicability

[0644] The resin compositions disclosed herein can form molded articles with good physical properties, and are therefore suitable for a wide range of applications, including industrial mechanical parts, general mechanical parts, automotive / railway / vehicle / ship / aerospace related parts, electronic / electrical parts, building / civil engineering materials, consumer goods, sports / leisure products, wind power generation shell components, container / packaging components, etc.

Claims

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

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

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

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. In the resin composition, the total amount of the acid-modified styrene elastomer and the styrene elastomer is 60% or more by mass in 100% by mass.

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. The acid-modified styrene-based elastomer is compatible with the styrene-based elastomer.

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. The amount of acid-modified styrene elastomer is 0.5 to 50 parts by mass relative to 100 parts by mass of the styrene elastomer.

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

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

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

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

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

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

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

14. The resin composition according to any one of claims 1 to 3, wherein, The resin composition comprises an acid-modified styrene-based elastomer as the thermoplastic elastomer. The acid-modified styrene elastomer is an acid-modified styrene elastomer that is an aromatic vinyl compound-conjugated diene compound block copolymer or its hydrogenated form.

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

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

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

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

19. 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. The ratio of the styrene unit proportion of the styrene-based elastomer to the styrene unit proportion of the acid-modified styrene-based elastomer, i.e., the styrene proportion of the styrene-based elastomer / styrene proportion of the acid-modified styrene-based elastomer, is 0.3 to 2.

5.

20. 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. The number-average molecular weight of the acid-modified styrene-based elastomer is 10,000 to 500,000.

21. The resin composition according to any one of claims 1 to 3, wherein, The resin composition comprises an acid-modified styrene-based elastomer as the thermoplastic elastomer. In the acid-modified styrene-based elastomer, the ratio of styrene unit proportion to acid modification rate, i.e., styrene unit proportion / acid modification rate, is 5 to 90.

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

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

24. The resin composition according to any one of claims 1 to 3, wherein, The thermal decomposition initiation temperature of the cellulose nanofibers is above 250℃.

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

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 manufacturing 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. The method includes the following steps: heating and mixing a mixture comprising the acid-modified styrene elastomer, the styrene elastomer, and the cellulose nanofibers.

29. The method according to claim 28, wherein, The weight increase rate of the heated and mixed cellulose nanofibers relative to the unheated and mixed cellulose nanofibers is 190% to 600%.

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

31. The resin molded article according to claim 30, wherein it is a profiled extruded article.

32. A method for manufacturing irregularly shaped extruded articles, wherein, The method includes the step of extruding the resin composition according to any one of claims 1 to 3 in a profile.

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

34. The 3D printing modeling material according to claim 33, wherein it has the morphology of filaments or powder.

35. A modeling object formed by molding the resin composition of any one of claims 1 to 3 using a 3D printer.

36. A modeling object formed by using a 3D printer with the 3D printing modeling material of claim 33.

37. A method for manufacturing a shaped object, wherein, The method includes a step of molding the resin composition according to any one of claims 1 to 3 using a 3D printer.

38. A method for manufacturing a shaped object, wherein, The method includes a step of using a 3D printer to shape the 3D printing modeling material of claim 33.

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

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