Resin composition

Abstract

To provide a resin composition capable of forming a resin molded body which is excellent in processability and handleability while exhibiting excellent properties inherent to a styrene-based elastomer, particularly good rubber elasticity, weather resistance, chemical resistance, and the like, and a method for producing the resin composition, and a resin molded body obtained by molding the resin composition.SOLUTION: In one aspect, a resin composition including a styrene-based elastomer and a tackiness-reducing agent containing cellulose nanofibers, a method for producing the resin composition, and a resin molded body obtained by molding the resin composition are provided.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a resin composition containing a styrenic elastomer.

Background Art

[0002] Thermoplastic elastomers have been conventionally used in a wide range of applications because they exhibit rubber elasticity and can be melt-molded by the same method as thermoplastic resins. Known thermoplastic elastomers include styrenic, olefinic, polyurethane, polyester, polyamide, acrylic, polyvinyl chloride-based ones, etc. Among these, styrenic elastomers are excellent in weather resistance, chemical resistance, etc., and have been used not only as sealing materials but also as modifiers, additives, etc. for various materials.

[0003] For example, in resin molded articles, it is generally common to contain fillers for the purpose of improving physical properties. In order for such a resin molded article containing a filler to exhibit desired properties, it is important that the filler is well dispersed in the resin. In recent years, due to the increasing awareness of environmental problems, various attempts have been made to use cellulose, which is a low-specific gravity and renewable material, as a filler to be contained in resin molded articles. However, since cellulose is generally hydrophilic due to its hydroxyl groups, it has been proposed to use a styrenic elastomer as an additive for well dispersing cellulose in a polymer.

[0004] Patent Document 1 describes a resin composition containing one or more elastomers selected from the group consisting of polyamide, an aromatic vinyl compound-conjugated diene compound block copolymer and derivatives thereof, and cellulose, wherein the polyamide and the elastomer are phase-separated, and more than 50% by mass of the cellulose is present in the polyamide phase.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Styrene-based elastomers are soft and excellent in weather resistance, chemical resistance, etc. Therefore, molded articles using styrene-based elastomers as the main polymer component are also desired. However, conventionally, the applications of resin molded articles using styrene-based elastomers as the main polymer component have been limited. Styrene-based elastomers generally exhibit tackiness (initial adhesiveness). For this reason, styrene-based elastomers have problems in processability and handleability, such as difficulty in melt molding of styrene-based elastomers alone and the tendency of styrene-based elastomer molded articles to stick to each other. The technique described in Patent Document 1 attempts to simultaneously achieve contradictory properties of high toughness and low thermal expansibility by using the above elastomer in a resin composition containing polyamide and cellulose, but it cannot provide a molded article using a styrene-based elastomer as the main polymer component.

[0007] The present invention solves the above problems and forms a resin molded article that exhibits excellent properties inherent in styrene-based elastomers (particularly, good rubber elasticity, weather resistance, chemical resistance, etc.) and is also excellent in processability and handleability, and aims to provide a resin composition, a method for producing the same, and a resin molded article formed by molding the resin composition.

Means for Solving the Problems

[0008] This disclosure includes the following items. [Item 1] A resin composition comprising a styrene-based elastomer and a tack inhibitor containing cellulose nanofibers. [Item 2] The resin composition according to Item 1, comprising 10% by mass or more of the styrene-based elastomer. [Item 3] The resin composition according to item 1 or 2, containing 0.1% to 20% by mass of the cellulose nanofibers. [Item 4] The resin composition according to any one of items 1 to 3, further containing an acid-modified styrene-based elastomer. [Item 5] The resin composition according to any one of items 1 to 4, wherein the styrene-based elastomer is an unmodified product. [Item 6] The resin composition according to any one of items 1 to 5, containing 0.5 to 250 parts by mass of the styrene-based elastomer with respect to 1 part by mass of the cellulose nanofibers. [Item 7] The resin composition according to any one of items 1 to 6, wherein the styrene-based elastomer is an aromatic vinyl compound-conjugated diene compound block copolymer or a hydrogenated product thereof. [Item 8] The resin composition according to any one of items 1 to 7, wherein the MFR of the styrene-based elastomer at 230 °C and 2.16 kg is 20 g / 10 minutes or less. [Item 9] The resin composition according to any one of items 1 to 8, wherein the styrene unit ratio of the styrene-based elastomer is 10 mol% to 40 mol%. [Item 10] The resin composition according to any one of items 1 to 9, wherein the number average molecular weight of the styrene-based elastomer is 10,000 to 500,000. [Item 11] The resin composition according to any one of items 1 to 10, wherein the number average fiber diameter of the cellulose nanofibers is 2 nm to 1000 nm. [Item 12] The resin composition according to any one of items 1 to 11, wherein the thermal decomposition start temperature of the cellulose nanofibers is 250 °C or higher. [Item 13] The resin composition according to any one of items 1 to 12, wherein the specific surface area of the cellulose nanofibers is 10 m 2 / g to 200 m 2 / g. [Item 14] The resin composition according to any one of Items 1 to 13, further comprising a dispersant. [Item 15] The resin composition according to Item 14, wherein the dispersant is a polymer containing a polyoxyethylene unit. [Item 16] The resin composition according to any one of Items 1 to 15, further comprising a liquid polymer. [Item 17] The resin composition comprises a thermoplastic elastomer containing the styrenic elastomer and an acid-modified styrenic elastomer, The resin composition according to any one of Items 1 to 16, wherein the amount of the thermoplastic elastomer is 60% by mass or more in 100% by mass of the resin composition. [Item 18] The resin composition comprises a thermoplastic elastomer containing the styrenic elastomer, The aspect ratio, which is the ratio L / D of the length L to the width D of the cellulose nanofiber, is 2 or more and 50 or less, The resin composition according to any one of Items 1 to 17, wherein the amount of the thermoplastic elastomer is 60% by mass or more in 100% by mass of the resin composition. [Item 19] The resin composition comprises a thermoplastic elastomer containing the styrenic elastomer, When the cellulose nanofiber is separated from the resin composition using tetrahydrofuran (THF), the weight increase rate of the cellulose nanofiber is 150% to 600%, The resin composition according to any one of Items 1 to 18, wherein the amount of the thermoplastic elastomer is 60% by mass or more in 100% by mass of the resin composition. [Item 20] A method for producing the resin composition according to any one of Items 1 to 19, The method includes a kneading step of heating and kneading a mixture containing a styrenic elastomer and cellulose nanofibers. [Item 21] The method according to item 20, wherein the cellulose nanofiber used in the kneading step is a dried product having a liquid medium content of 7% by mass or less. [Item 22] A resin molded article formed by molding the resin composition according to any one of items 1 to 19. [Item 23] The resin molded article according to item 22, which is a profile extrusion molded article. [Item 24] A method for manufacturing a profile extrusion molded article, comprising: a step of profile extruding the resin composition according to any one of items 1 to 19. [Item 25] A molding material for 3D printing composed of the resin composition according to any one of items 1 to 19. [Item 26] The molding material for 3D printing according to item 25, which has a form of a filament or powder. [Item 27] A molded article formed by molding the resin composition according to any one of items 1 to 19 or the molding material for 3D printing according to item 25 or 26 using a 3D printer. [Item 28] A method for manufacturing a molded article, comprising: a step of molding the resin composition according to any one of items 1 to 19 or the molding material for 3D printing according to item 25 or 26 using a 3D printer. [Advantages of the Invention]

[0009] According to one aspect of the present invention, there can be provided a resin composition capable of forming a resin molded article that exhibits excellent properties (particularly, good rubber elasticity, weather resistance, chemical resistance, etc.) inherent in a styrene-based elastomer and is also excellent in processability and handleability, a method for manufacturing the same, and a resin molded article formed by molding the resin composition. [Modes for Carrying Out the Invention]

[0010] Hereinafter, exemplary embodiments of the present invention (hereinafter also referred to as the present embodiments) will be described. However, the present invention is not limited to these embodiments, and various modifications can be made within the scope of the gist thereof.

[0011] ≪Resin Composition≫ One aspect of the present invention provides a resin composition including a styrenic elastomer and a tack inhibitor containing cellulose nanofibers. Styrenic elastomers inherently have good rubber elasticity, weather resistance, chemical resistance, etc., but due to their tackiness, they are difficult to mold and tend to be difficult to handle in the molded article. For example, a molding material having tackiness is difficult to release from the mold during molding, and when a strong force is applied to the molded article to peel it from the mold, it is deformed or damaged, making it difficult to obtain a good molded article. Further, when storing molded articles such as pellets, bales, injection molded articles, films, sheets, filaments, etc. having tackiness, the contact portions between the molded articles are blocked, causing a situation that is difficult to handle in any process. In the resin composition of the present embodiment, it has been found that the presence of cellulose nanofibers suppresses the tackiness, making the molding easy and the molded article easy to handle. The cellulose nanofibers according to one aspect can function as a tack inhibitor alone or in cooperation with other components in the resin composition. The reason why cellulose nanofibers are excellent in the tack reduction effect of styrenic elastomers is not clear, but due to the contribution of the fine fibrous structure of cellulose nanofibers, they are more likely to physically entangle with styrenic elastomers compared to other fillers (e.g., silica particles, glass fibers, carbon fibers, etc.), so there is a possibility of exhibiting a good tack reduction effect. Since cellulose nanofibers are softer than, for example, silica particles, glass fibers, carbon fibers, etc., they are also advantageous in that they do not impair the rubber elasticity inherent in styrenic elastomers. Furthermore, adding cellulose nanofibers to styrenic elastomers can also be advantageous for reducing shrinkage during molding and improving the tensile strength, tensile elastic modulus, tensile elongation at break and / or hardness of the molded article. The resin composition of the present embodiment is useful as a soft resin molded article because it suppresses tackiness while using a styrenic elastomer and has excellent processability and handleability, and is also suitable as a substitute for, for example, thermoplastic polyurethane elastomer (TPU).

[0012] The tack strength of the resin composition of this embodiment at 23°C, a load of 600 gf, a pressing time of 60 seconds, and a peeling rate of 600 mm / min measured by the probe tack test (hereinafter, may be simply referred to as tack strength) is 10.0 gf / mm 2 or less. In one aspect, the above-mentioned tack strength is 9.0 gf / mm 2 or less, or 7.0 gf / mm 2 or less, or 5.0 gf / mm 2 or less, or 3.0 gf / mm 2 or less, or 2.0 gf / mm 2 or less, or 1.5 gf / mm 2 or less, or 1.0 gf / mm 2 or less. In one aspect, from the perspective of the ease of manufacturing the resin composition, the above-mentioned tack strength is 0.001 gf / mm 2 or more, or 0.01 gf / mm 2 or more, or 0.1 gf / mm 2 or more, or 0.3 gf / mm 2 or more, or 0.5 gf / mm 2 or more.

[0013] The tack strength of the resin composition of this embodiment is preferably 70% or less, or 60% or less, or 50% or less, or 40% or less, or 30% or less, or 25% or less, or 20% or less, or 15% or less, or 10% or less, relative to 100% of the tack strength of a resin composition having the same composition except for not containing cellulose nanofibers. From the perspective of tack suppression, the smaller the above ratio is, the more desirable it is. However, from the perspective of the ease of manufacturing the resin composition, in one aspect, it may be 0.0001% or more, or 0.1% or more, or 1% or more, or 3% or more. It is also preferable that the tack strength of the resin composition of this embodiment shows the above-exemplified ratio with respect to 100% of the tack strength of the styrene-based elastomer contained in the resin composition.

[0014] The components of the resin composition will be described below. In this embodiment, the amount of each component described as a value in the resin composition components may be regarded as the amount of each component in the resin composition, and the amount of each component described as a value in the resin composition may also be regarded as the amount of each component in the resin composition components.

[0015] <Cellulose nanofiber> Cellulose nanofibers are fibers obtained by refining a cellulose fiber raw material by a defibrillation treatment or the like. As the cellulose fiber raw material, natural cellulose and regenerated cellulose can be used. As the natural cellulose, wood pulp obtained from wood species (hardwood or softwood), non-wood pulp obtained from non-wood species (cotton, bamboo, hemp, bagasse, kenaf, cotton linter, sisal, straw, etc.), cellulose fiber aggregates produced by animals (e.g., tunicates), algae, and microorganisms (e.g., acetic acid bacteria) can be used. As the regenerated cellulose, regenerated cellulose fibers (viscose, cupra, tencel, etc.), cellulose derivative fibers, regenerated cellulose or ultrafine filaments of cellulose derivatives obtained by an electrospinning method can be used. A cellulose fiber raw material that gives cellulose nanofibers having fibrillation on the surface may be advantageous in the tack suppression effect. From this viewpoint, preferred cellulose fiber raw materials include cotton linter and the like.

[0016] In one aspect, defibrillation is a dry or wet mechanical treatment, preferably a wet treatment in which a mechanical treatment is applied to a slurry obtained by dispersing a cellulose fiber raw material in a liquid medium. A single device may be used once or more for defibrillation, or a plurality of devices may be used once or more respectively. The device used for defibrillation is not particularly limited, and examples include devices of types such as high-speed rotation type, colloid mill type, high-pressure type, roll mill type, ultrasonic type, etc., and high-pressure or ultra-high-pressure homogenizers, refiners, beaters, PFI mills, kneaders, dispersers, high-speed defibrillators, grinders (mortar type grinders), ball mills, vibration mills, bead mills, conical refiners, disk refiners, single-axis, two-axis or multi-axis kneaders and extruders.

[0017] The cellulose fiber raw material may be subjected to pretreatment before fibrillation. By the pretreatment, the fiber diameter, fiber length, fibrillation degree, etc. can be adjusted, the content of components other than cellulose (acid-insoluble components such as lignin, alkali-soluble polysaccharides such as hemicellulose, etc.) can be adjusted, the molecular weight, crystallinity, etc. can be adjusted.

[0018] In one aspect, the pretreatment may be one or more selected from chemical treatment, pulverization, grinding, and classification. Chemical treatment is a treatment using chemicals, and examples include cooking, bleaching, purification, hydrolysis treatment, enzyme treatment, regeneration of cellulose, and chemical modification. Pulverization is a treatment for dry-pulverizing the cellulose fiber raw material. Grinding is a treatment for subjecting the slurry obtained by dispersing the cellulose fiber raw material in a liquid medium to a pulverization treatment, and is distinguished from the above-mentioned pulverization in that it is wet. Classification is a separation operation for aligning the fiber lengths of the cellulose fiber raw material, and may be dry classification or wet classification.

[0019] Examples of the liquid medium include water and / or other media (for example, organic solvents, inorganic acids, bases, and / or ionic liquids), and may contain one type or two or more types of media.

[0020] Examples of the organic solvent include commonly used organic solvents such as alcohols (for example, methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, s-butanol, t-butanol, ethylene glycol, diethylene glycol, glycerin, etc.); ethers (for example, propylene glycol monomethyl ether, 1,2-dimethoxyethane, diisopropyl ether, tetrahydrofuran, 1,4-dioxane, etc.); carboxylic acids (for example, formic acid, acetic acid, lactic acid, etc.); esters (for example, ethyl acetate, vinyl acetate, etc.); ketones (for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, etc.); nitrogen-containing solvents (dimethylformamide, dimethylacetamide, acetonitrile, etc.); sulfur-containing solvents (dimethyl sulfoxide). One or more of them are included. In a typical aspect, the liquid medium in the slurry is substantially only water.

[0021] In one aspect, the number-average fiber length L of the cellulose nanofibers is preferably 100 nm or more, or 500 nm or more, 1 μm or more, or 5 μm or more, or 10 μm or more, or 20 μm or more from the viewpoint of favorably exhibiting the physical property improving effect by the cellulose nanofibers, and preferably 1000 μm or less, or 800 μm or less, or 500 μm or less, or 400 μm or less, or 300 μm or less, or 200 μm or less from the viewpoint of favorably dispersing the cellulose nanofibers in the resin composition.

[0022] In one aspect, the number-average fiber diameter D of the cellulose nanofibers is preferably 2 to 1000 nm from the viewpoint of favorably obtaining the physical property improving effect by the cellulose nanofibers. The number-average fiber diameter of the cellulose nanofibers is more preferably 4 nm or more, or 5 nm or more, or 10 nm or more, or 15 nm or more, or 20 nm or more, and more preferably 900 nm or less, or 800 nm or less, or 700 nm or less, or 600 nm or less, or 500 nm or less, or 400 nm or less, or 300 nm or less, or 200 nm or less.

[0023] 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 from the viewpoint of favorably improving the mechanical properties of the rubber composite containing the cellulose nanofibers with a small amount of cellulose nanofibers. The upper limit is not particularly limited, but is preferably 5000 or less, or 3000 or less, or 2000 or less, or 1000 or less from the viewpoint of handleability.

[0024] In the present disclosure, the fiber length, fiber diameter, and L / D ratio of cellulose nanofibers are values measured by the following procedure using a scanning electron microscope (SEM). A water dispersion of cellulose nanofibers is replaced with tert-butanol, diluted to 0.001 to 0.1 mass%, and dispersed using a high-shear homogenizer (for example, manufactured by IKA, trade name "Ultra Turrax T18") under the treatment conditions: rotation speed of 15,000 rpm for 3 minutes. The sample is cast on an osmium-evaporated silicon substrate and air-dried, and the measurement sample is measured with a high-resolution scanning electron microscope (SEM). Specifically, in an observation field where the magnification is adjusted so that at least 100 cellulose nanofibers are observed, the lengths (L) and diameters (D) of 100 randomly selected cellulose nanofibers are measured, and the ratio (L / D) is calculated. Then, the respective number average values are taken as the number average fiber length L and the number average fiber diameter D, and the ratio (L / D) is calculated.

[0025] The number average aspect ratio, which is the ratio L / D of the number average fiber length L to the number average fiber diameter D of cellulose nanofibers in the resin composition, is, in one aspect, 2 or more and 50 or less. The upper limit of the aspect ratio is not particularly limited, but from the viewpoint of handleability, it is preferably 50 or less, or 26 or less, or 25 or less. The aspect ratio is a value measured by the method described in the [Examples] section of the present disclosure.

[0026] As crystal forms of cellulose, type I, type II, type III, type IV, etc. are known. Among them, type I and type II are particularly widely used. Although type III and type IV are obtained on a laboratory scale, they are not widely used on an industrial scale. As the cellulose nanofibers of the present disclosure, those having relatively high structural mobility, and by dispersing the cellulose nanofibers in rubber, a molded article having a lower linear expansion coefficient and more excellent strength and elongation during tensile and bending deformation can be obtained. Therefore, cellulose nanofibers containing cellulose type I crystal or cellulose type II crystal are preferred, and cellulose nanofibers containing cellulose type I crystal and having a crystallinity of 55% or more are more preferred.

[0027] The crystallinity of the cellulose nanofibers is preferably 55% or more. The greater the crystallinity, the higher the mechanical properties (strength, dimensional stability) of the cellulose itself. Therefore, when the cellulose nanofibers are dispersed in the rubber, the strength and dimensional stability of the rubber composite tend to be high. The lower limit of the more preferable crystallinity is 60%, even more preferably 70%, and most preferably 80%. There is no particular limitation on the upper limit of the crystallinity of the cellulose nanofibers, and a higher value is preferable. However, from the perspective of production, the preferable upper limit is 99%.

[0028] The crystallinity referred to here, when the cellulose nanofibers are of cellulose I type crystals (derived from natural cellulose), is determined by the Segal method from the diffraction pattern (2θ / deg. is 10 - 30) when the sample is measured by wide-angle X-ray diffraction, according to the following formula. Crystallinity (%) = [I (200) - I (amorphous) / I (200) × 100 I (200) : Diffraction peak intensity by the 200 plane (2θ = 22.5°) in cellulose I type crystals I (amorphous) : Halo peak intensity by the amorphous in cellulose I type crystals, which is the peak intensity on the 4.5° lower angle side (2θ = 18.0°) than the diffraction angle of the 200 plane

[0029] Also, when the cellulose is of cellulose II type crystals (derived from regenerated cellulose), the crystallinity is determined by the following formula from the absolute peak intensity h0 at 2θ = 12.6° attributed to the (110) plane peak of the cellulose II type crystals and the peak intensity h1 of the baseline (the line connecting 2θ = 8° and 15°) at this plane spacing in wide-angle X-ray diffraction. Crystallinity (%) = (h0 - h1) / h0 × 100

[0030] Also, the degree of polymerization of the cellulose nanofibers is preferably 100 or more, more preferably 150 or more, more preferably 200 or more, more preferably 300 or more, more preferably 400 or more, more preferably 450 or more, and preferably 3500 or less, more preferably 3300 or less, more preferably 3200 or less, more preferably 3100 or less, more preferably 3000 or less.

[0031] From the viewpoints of processability and manifestation of mechanical properties, it is desirable that the degree of polymerization of the cellulose nanofibers be within the above-described range. From the viewpoint of processability, it is preferable that the degree of polymerization not be too high, and from the viewpoint of manifestation of mechanical properties, it is desired that it not be too low.

[0032] The degree of polymerization of the cellulose nanofibers means the average degree of polymerization measured according to the reduced viscosity method using a copper ethylenediamine solution described in the confirmation test (3) of the "Fifteenth Revised Japanese Pharmacopoeia Explanation Book (published by Hirokawa Shoten)".

[0033] In one aspect, the weight average molecular weight (Mw) of the cellulose nanofibers is 100,000 or more, more preferably 200,000 or more. The ratio (Mw / Mn) of the weight average molecular weight to the number average molecular weight (Mn) is 6 or less, preferably 5.6 or less, or 5.4 or less. A larger weight average molecular weight means fewer end groups of the cellulose molecules. Also, since the ratio (Mw / Mn) of the weight average molecular weight to the number average molecular weight represents the width of the molecular weight distribution, a smaller Mw / Mn means fewer ends of the cellulose molecules. Since the ends of the cellulose molecules serve as the starting point of thermal decomposition, particularly highly heat-resistant cellulose nanofibers and resin compositions containing cellulose nanofibers can be obtained when not only the weight average molecular weight of the cellulose molecules of the cellulose nanofibers is large, but also the weight average molecular weight is large and the width of the molecular weight distribution is narrow at the same time. The weight average molecular weight (Mw) of the cellulose nanofibers may be, for example, 600,000 or less, or 500,000 or less, or 400,000 or less, from the viewpoint of the availability of the cellulose raw material. The number average molecular weight (Mn) of the cellulose nanofibers may be, for example, 200,000 or less, or 150,000 or less, or 100,000 or less, or 80,000 or less, or 60,000 or less, from the viewpoint of the availability of the cellulose fiber raw material. The ratio (Mw / Mn) of the weight average molecular weight to the number average molecular weight (Mn) may be, for example, 1.5 or more, or 1.7 or more, or 2 or more, from the viewpoint of the ease of production of the cellulose nanofibers. Mw can be controlled within the above range by selecting a cellulose raw material having an Mw suitable for the purpose, appropriately performing physical treatment and / or chemical treatment on the cellulose raw material within an appropriate range, and the like. Mw / Mn can also be controlled within the above range by selecting a cellulose raw material having an Mw / Mn suitable for the purpose, appropriately performing physical treatment and / or chemical treatment on the cellulose raw material within an appropriate range, and the like. Each of the Mw and Mw / Mn of the cellulose raw material may be within the above range in one aspect.

[0034] The weight-average molecular weight and number-average molecular weight of the cellulose nanofibers referred to herein are values obtained by dissolving the cellulose nanofibers in N,N-dimethylacetamide with added lithium chloride and then determining them by gel permeation chromatography using N,N-dimethylacetamide as a solvent.

[0035] Alkaline-soluble polysaccharides that may be contained in the cellulose nanofibers include, in addition to hemicellulose, β-cellulose and γ-cellulose. Alkaline-soluble polysaccharides are understood by those skilled in the art as components obtained as the alkali-soluble part of holocellulose obtained by solvent extraction and chlorination treatment of plants (e.g., wood) (i.e., components obtained by removing α-cellulose from holocellulose). Alkaline-soluble polysaccharides are polysaccharides containing hydroxyl groups and have poor heat resistance, and may cause disadvantages such as decomposition when heated, yellowing during heat aging, and a decrease in the strength of cellulose nanofibers. Therefore, it is preferable that the content of alkaline-soluble polysaccharides in the cellulose nanofibers is low.

[0036] In one aspect, from the viewpoint of obtaining good dispersibility of the cellulose nanofibers, the average content rate of alkaline-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, based on 100% by mass of the cellulose nanofibers. From the viewpoint of the ease of manufacturing the cellulose nanofibers, the above content rate may be 1% by mass or more, or 2% by mass or more, or 3% by mass or more.

[0037] The average content rate of alkaline-soluble polysaccharides can be determined by the method described in a non-patent document (Wood Science Experiment Manual, edited by the Japanese Wood Research Society, pages 92-97, 2000), and is obtained by subtracting the α-cellulose content rate from the holocellulose content rate (Wise method). This method is understood in the art as a method for measuring the amount of hemicellulose. The alkaline-soluble polysaccharide content rate is calculated three times for one sample, and the number average of the calculated alkaline-soluble polysaccharide content rates is taken as the average content rate of alkaline-soluble polysaccharides.

[0038] In one aspect, from the viewpoint of avoiding a decrease in heat resistance of the cellulose nanofibers and the accompanying discoloration, the average content rate of the acid-insoluble component in the cellulose nanofibers is preferably 10% by mass or less, or 5% by mass or less, or 3% by mass or less with respect to 100% by mass of the cellulose nanofibers. From the viewpoint of the ease of manufacturing the cellulose nanofibers, the above content rate may be 0.1% by mass or more, or 0.2% by mass or more, or 0.3% by mass or more.

[0039] The average content rate of the acid-insoluble component is determined as the quantification of the acid-insoluble component using the Klason method described in the non-patent literature (Wood Science Experiment Manual, edited by the Japan Wood Research Society, pages 92 to 97, 2000). This method is understood in the industry as a method for measuring the amount of lignin. After stirring the sample in a sulfuric acid solution to dissolve cellulose, hemicellulose, etc., it is filtered through a glass fiber filter paper, and the obtained residue corresponds to the acid-insoluble component. The acid-insoluble component content rate is calculated from the weight of this acid-insoluble component. Then, the acid-insoluble component content rate is measured three times for one sample, and the number average thereof is taken as the average content rate of the acid-insoluble component.

[0040] [Chemical modification] The cellulose nanofibers may be chemically modified cellulose nanofibers (also referred to as chemically modified cellulose nanofibers). Examples of the chemically modified cellulose nanofibers include inorganic esterified products such as nitrate esters, sulfate esters, phosphate esters, silicate esters, and borate esters, organic esterified products such as acetylation and propionylation, etherified products such as methyl ether, hydroxyethyl ether, hydroxypropyl ether, hydroxybutyl ether, carboxymethyl ether, and cyanoethyl ether, and TEMPO oxides formed by oxidizing the primary hydroxyl groups of cellulose. The chemically modified cellulose nanofibers may contain one type or two or more types of modifying groups. In a preferred embodiment, the chemical modification is acylation using an esterifying agent, and particularly preferably acetylation. Preferred esterifying agents include acid halides, acid anhydrides, and vinyl carboxylates and carboxylic acids. Among these esterifying agents, in particular, at least one selected from the group consisting of acetic anhydride, propionic anhydride, butyric anhydride, vinyl acetate, vinyl propionate, vinyl butyrate, and acetic acid, and among them, acetic anhydride and vinyl acetate are preferred from the viewpoint of reaction efficiency. The cellulose nanofibers may be chemically modified by a modifying agent, for example, at the stage of the cellulose fiber raw material, during the fibrillation process, or after the fibrillation process, or may be chemically modified during or after the preparation of the slurry as a dispersion, or during or after the drying process.

[0041] [Degree of acyl substitution (DS)] When the cellulose nanofibers are chemically modified (for example, by hydrophobization such as acylation), the dispersibility of the cellulose nanofibers in the rubber tends to be good. On the other hand, for example, when combined with a dispersant, it is easy for the cellulose nanofibers to exhibit good dispersibility in the rubber even if they are unsubstituted or have a low degree of substitution. When the cellulose nanofibers are esterified cellulose nanofibers, the degree of acyl substitution (DS) is preferably 0.1 or more, or 0.2 or more, or 0.25 or more, or 0.3 or more, or 0.5 or more in terms of obtaining an esterified cellulose nanofiber having a high thermal decomposition start temperature. Since an unmodified cellulose skeleton remains in the esterified cellulose nanofibers, it is possible to obtain an esterified cellulose nanofiber having both high tensile strength and dimensional stability derived from cellulose and a high thermal decomposition start temperature derived from chemical modification. Preferably, it is 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.

[0042] When the modifying group of the chemically modified cellulose nanofiber is an acyl group, the degree of acyl substitution (DS) can be calculated based on the peak intensity ratio between the peak derived from the acyl group and the peak derived from the cellulose backbone in the reflection infrared absorption spectrum of the esterified cellulose nanofiber. The peak of the absorption band of C=O based on the acyl group appears at 1730 cm -1 and the peak of the absorption band of C-O based on the cellulose backbone chain appears at 1030 cm -1 . The DS of the esterified cellulose nanofiber can be obtained from the DS obtained from the solid NMR measurement of the esterified cellulose nanofiber described later, and the modification rate (IR index 1030) defined by the ratio of the peak intensity of the absorption band of C=O based on the acyl group to the peak intensity of the absorption band of C-O of the cellulose backbone chain. A correlation graph is created, and the calibration curve Degree of substitution DS = 4.13 × IR index (1030) can be obtained by using it. IR index (1030)= H1730 / H1030 In the formula, H1730 and H1030 are the absorbances at 1730 cm -1 , 1030 cm -1 (absorption band of cellulose backbone chain C-O stretching vibration). However, the absorbance when this baseline is set to absorbance 0 means the absorbance when the lines connecting 1900 cm -1 and 1500 cm -1 and the lines connecting 800 cm -1 and 1500 cm -1 are used as the baseline.

[0043] The method for calculating the DS of the esterified cellulose nanofiber by solid NMR is as follows for the freeze-milled esterified cellulose nanofiber 13 Perform 13C solid NMR measurement, and it can be obtained from the following formula based on the area intensity (Inf) of the signal attributed to one carbon atom derived from the modifying group with respect to the total area intensity (Inp) of the signals attributed to the carbon C1-C6 derived from the pyranose ring of cellulose that appears in the range of 50 ppm to 110 ppm. DS = (Inf)×6 / (Inp) For example, when the modifying group is an acetyl group, the signal at 23 ppm attributed to -CH3 may be used. Use 13 The conditions for solid-state C NMR measurement are as follows, for example. Apparatus: Bruker Biospin Avance500WB Frequency: 125.77 MHz Measurement method: DD / MAS method Waiting time: 75 sec NMR sample tube: 4 mm φ Number of integrations: 640 times (about 14 Hr) MAS: 14,500 Hz Chemical shift standard: Glycine (external standard: 176.03 ppm)

[0044] The thermal decomposition start temperature (T D ) of cellulose nanofibers is preferably, in one aspect, 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, from the viewpoint of exhibiting heat resistance and mechanical strength desired for in-vehicle applications and the like. Although the higher the thermal decomposition start temperature is, the more preferable it is, from the viewpoint of the ease of manufacturing cellulose nanofibers, it may be, for example, 320 °C or lower, or 310 °C or lower, or 300 °C or lower.

[0045] [Temperature at 1% weight loss (T 1% ), weight loss rate at 250 °C (T 250℃ )] The temperature (T 1% ) at which cellulose nanofibers lose 1 wt% of their weight is preferably, in one aspect, 230 °C or higher, or 240 °C or higher, or 250 °C or higher, or 260 °C or higher, or 270 °C or higher, or 275 °C or higher, or 280 °C or higher, or 285 °C or higher, or 290 °C or higher, from the viewpoint of avoiding thermal degradation during melt-kneading and exhibiting mechanical strength. T 1%Although it is preferably higher, from the viewpoint of the ease of manufacturing cellulose nanofibers, it may be, for example, 330°C or lower, or 320°C or lower, or 310°C or lower.

[0046] The weight loss rate (T 250℃ ) of cellulose nanofibers at 250°C preferably satisfies, from the viewpoint of avoiding thermal degradation during melt kneading and exhibiting mechanical strength, in one aspect, 15% or less, or 12% or less, or 10% or less, or 8% or less, or 6% or less, or 5% or less, or 4% or less, or 3% or less in one aspect. T 250℃ Although it is preferably lower, from the viewpoint of the ease of manufacturing cellulose nanofibers, it may be, for example, 0.1% or more, or 0.5% or more, or 0.7% or more, or 1.0% or more.

[0047] In the present disclosure, T D is a value obtained from a graph with temperature on the horizontal axis and weight retention rate (%) on the vertical axis in thermogravimetric (TG) analysis. Starting from the weight at 150°C (state where moisture is almost removed) of cellulose nanofibers (weight loss amount 0 wt%), the temperature is further increased, and a straight line passing through the temperature (T 1% ) at 1 wt% weight loss and the temperature (T 2% ) at 2 wt% weight loss is obtained. The temperature at the intersection point of this straight line and the horizontal line (baseline) passing through the starting point of 0 wt% weight loss amount is defined as T D .

[0048] The 1% weight loss temperature (T 1% ) is the temperature at 1 wt% weight loss starting from the weight at 150°C when the temperature is continuously increased by the method of the above T D .

[0049] The weight loss rate (T 250℃) is the weight loss rate when cellulose nanofibers are held at 250 °C for 2 hours under a nitrogen flow in TG analysis. The porous sheet of cellulose nanofibers is heated from room temperature to 150 °C at a heating rate of 10 °C / min in a nitrogen flow of 100 ml / min, held at 150 °C for 1 hour, then heated from 150 °C to 250 °C at a heating rate of 10 °C / min, and kept at 250 °C for 2 hours as it is. Starting from the weight W0 at the time of reaching 250 °C, the weight after holding at 250 °C for 2 hours is taken as W1 and calculated from the following formula. Weight change rate at 250 °C (%): (W1 - W0) / W0 × 100

[0050] [Porous sheet] Various physical properties of cellulose nanofibers (crystallinity, crystal polymorphism, degree of polymerization, Mw, Mn, Mw / Mn, alkali-soluble content, average content of acid-insoluble components, T D , T 1% , T 250℃ etc.) may vary greatly in numerical values depending on the form of the measurement sample. In order to perform measurements with stable reproducibility, a porous sheet without strain is used as the measurement sample. The method for producing the porous sheet is as follows.

[0051] First, a concentrated cake of cellulose nanofibers with a solid content rate of 10 mass% or more is added to tert-butanol, and further dispersion treatment is carried out with a mixer or the like until there are no aggregates. It is adjusted so that the concentration becomes 0.5 mass% with respect to 0.5 g of the cellulose nanofiber solid content weight. 100 g of the obtained tert-butanol dispersion is filtered on filter paper. Without peeling the filtrate from the filter paper, it is sandwiched between two larger filter papers together with the filter paper, and while pressing the edges of the larger filter paper with weights, it is dried in an oven at 150 °C for 5 minutes. Then, the filter paper is peeled off to obtain a porous sheet with little strain. A porous sheet with an air permeability resistance R of 100 sec / 100 ml or less per sheet basis weight of 10 g / m 2 is used as the porous sheet and as the measurement sample.

[0052] The measurement of the air permeability resistance R is carried out by measuring the basis weight W (g / m 2 ) of the porous sheet sample left standing for one day in an environment of 23°C and 50% RH, and then measuring the air permeability resistance R (sec / 100ml) using a Wang Research air permeability resistance tester (for example, manufactured by Asahi Seiko Co., Ltd., model EG01). At this time, according to the following formula, the value per unit basis weight is calculated. 2 Air permeability resistance per 10 g / m basis weight (sec / 100ml) = R / W × 10 2

[0053] [Specific surface area] The specific surface area of the cellulose nanofibers is preferably 10 m 2 / g or more, or 15 m 2 / g or more, or 20 m 2 / g or more, or 30 m 2 / g or more, or 40 m 2 / g or more, or 50 m 2 / g or more, because the transparency of the resin composition is good due to the highly refined cellulose nanofibers. From the viewpoint of the ease of production and handling of the cellulose nanofibers, it is preferably 200 m 2 / g or less, or 170 m 2 / g or less, or 160 m 2 / g or less. The specific surface area is measured by a specific surface area and pore size distribution measuring device (for example, Nova-4200e, manufactured by Quantachrome Instruments). After drying about 0.2 g of the sample under vacuum at 120°C for 5 hours, the nitrogen gas adsorption amount at the boiling point of liquid nitrogen is measured at 5 points in the range where the relative vapor pressure (P / P0) is 0.05 or more and 0.2 or less (multi-point method), and the BET specific surface area (m 2 / g) is calculated by the program of the same device. Cellulose nanofibers with a relatively large specific surface area may be advantageous in the tack suppression effect. From this viewpoint, the preferred specific surface area is 10 m 2 / g or more, or 20 m 2 / g or more, or 30 m 2 / g or more.

[0054] Various physical properties of cellulose nanofibers (number average fiber length, number average fiber diameter, L / D ratio, crystallinity, crystal polymorphism, degree of polymerization, Mw, Mn, Mw / Mn, alkali-soluble content, average acid-insoluble component content, T D 、T 1% 、T 250℃ 、DS, specific surface area, etc.) are analyzed by the following method. Dissolve the polymer component in an organic or inorganic solvent capable of dissolving the polymer component contained in the resin composition, etc., separate the cellulose nanofibers, thoroughly wash with the solvent, and then replace the solvent with tert-butanol. Thereafter, analyze the cellulose nanofiber tert-butanol slurry using the same measurement method as the above method, and calculate various physical properties of the cellulose nanofibers in the resin composition.

[0055] When separating cellulose nanofibers from a resin composition using THF, the weight increase rate of the cellulose nanofibers is preferably 150% or more, or 170% or more, or 190% or more from the viewpoint of the interfacial strength between the resin and the cellulose nanofibers, and preferably 600% or less, or 550% or less, or 500% or less from the viewpoint of suppressing short fiber formation during kneading. The weight increase rate is a value measured by the method described in the [Examples] section of the present disclosure.

[0056] In one aspect, the cellulose nanofibers may be provided in the form of a slurry containing a liquid medium or in the form of a dry body such as particles, films, or bulk. Examples of the liquid medium include water and / or an organic solvent having a boiling point, and may contain one or more types of media. The slurry form has a liquid medium content of 50% by mass or more, and the liquid medium content in the dry body is less than 50% by mass. The liquid medium content is a value measured when heated at 180 ° C using an infrared heating moisture meter (for example, manufactured by A&D Company, Ltd., trade name "MX-50"). From the viewpoint of obtaining a better tack suppressing effect, it is preferable that the form of the cellulose nanofibers mixed with the styrene-based elastomer is a dry body.

[0057] The amount of cellulose nanofibers in 100% by mass of the resin composition is preferably 0.1% by mass or more, or 0.3% by mass or more, or 0.4% by mass or more, or 0.5% by mass or more, or 0.7% by mass or more, or 1.0% by mass or more from the viewpoint of favorably obtaining the advantages of cellulose nanofibers, and is preferably 20% by mass or less, or 15% by mass or less, or 10% by mass or less from the viewpoint of the impact resistance of the resin composition. The amount of cellulose nanofibers that is particularly preferable from the viewpoint of favorably exhibiting the tack suppressing effect is 0.5% by mass or more, or 0.7% by mass or more, or 1.0% by mass or more.

[0058] <Thermoplastic elastomer> In one aspect, the resin composition includes a thermoplastic elastomer containing the styrenic elastomer of the present disclosure. In one aspect, the resin composition includes a thermoplastic elastomer containing the styrenic elastomer and an acid-modified styrenic elastomer. In the present disclosure, an elastomer is, in one aspect, a substance (specifically, a natural or synthetic polymeric substance) that is an elastic body at room temperature (23°C). Further, being an elastic body means, in one aspect, that the storage elastic modulus at 23°C and 10 Hz measured by dynamic viscoelasticity measurement is 1 MPa or more and 100 MPa or less. Examples of elastomers that the thermoplastic elastomer may contain in addition to the styrenic elastomer and the acid-modified styrenic elastomer include natural rubber, conjugated diene compound polymers, aromatic compound-conjugated diene copolymers, hydrogenated products of aromatic compound-conjugated diene copolymers, polyolefins, polyester-based elastomers, polyurethane-based elastomers, polyamide-based elastomers, and one or more selected from elastomers having a core-shell structure. The amount of the thermoplastic elastomer in 100% by mass of the resin composition is preferably 10% by mass or more, or 30% by mass or more, or 50% by mass or more, or 60% by mass or more, or 70% by mass or more, or 80% by mass or more from the viewpoint of flexibility, and is preferably 99.5% by mass or less, or 99% by mass or less, or 98% by mass or less, or 95% by mass or less, or 90% by mass or less from the viewpoint of containing other components in a desired amount. In one aspect, the total ratio of the styrenic elastomer and the acid-modified elastomer to 100% by mass of the thermoplastic elastomer may be 1% by mass or more, or 5% by mass or more, or 10% by mass or more, or 20% by mass or more, or 50% by mass or more, or 70% by mass or more, and in one aspect, it may be 100% by mass.

[0059] <Styrenic elastomer> In one aspect, the resin composition contains a styrenic elastomer. In one aspect, the styrenic elastomer is a copolymer of a conjugated diene monomer and an aromatic vinyl monomer. Examples of the conjugated diene monomer include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1,3-heptadiene, and 1,3-hexadiene, and these may be used alone or in combination of two or more. The aromatic vinyl monomer is not particularly limited as long as it is a monomer copolymerizable with the conjugated diene monomer. For example, styrene, m- or p-methylstyrene, α-methylstyrene, ethylstyrene, p-tert-butylstyrene, vinyl ethylbenzene, vinyl xylene, vinyl naphthalene, diphenylethylene, and divinylbenzene may be mentioned, and these may be used alone or in combination of two or more. From the viewpoints of the moldability of the resin composition and the impact resistance of the molded article, styrene is preferred.

[0060] Examples of the random copolymer include a butadiene-styrene random copolymer, an isoprene-styrene random copolymer, and a butadiene-isoprene-styrene random copolymer. Examples of the composition distribution of each monomer in the copolymer chain include a perfect random copolymer close to a statistically random composition and a tapered (gradient) random copolymer having a gradient in the composition distribution. The bonding mode of the conjugated diene polymer, that is, the composition of 1,4-bond, 1,2-bond, etc., may be uniform or different between molecules.

[0061] The block copolymer may be a copolymer composed of two or more blocks. For example, it may be a block copolymer in which block A of an aromatic vinyl monomer and block B which is a block of a conjugated diene monomer and / or a copolymer of an aromatic vinyl monomer and a conjugated diene monomer form a structure such as A-B, A-B-A, A-B-A-B, etc. Note that the boundary of each block does not necessarily have to be clearly distinguished. For example, when block B is a copolymer of an aromatic vinyl monomer and a conjugated diene monomer, the aromatic vinyl monomer in block B may be distributed uniformly or in a tapered shape. Also, there may be a plurality of portions in block B where the aromatic vinyl monomer is uniformly distributed and / or portions where it is distributed in a tapered shape, respectively. Further, there may be a plurality of segments with different aromatic vinyl monomer contents in block B. When there are a plurality of block A and block B in the copolymer, their molecular weights and compositions may be the same or different.

[0062] The styrenic elastomer may be an aromatic vinyl compound-conjugated diene compound block copolymer or a hydrogenated product thereof. The block copolymer may be a mixture of two or more kinds in which one or more of the bonding form, molecular weight, aromatic vinyl compound species, conjugated diene compound species, 1,2-vinyl content or the total amount of 1,2-vinyl content and 3,4-vinyl content, aromatic vinyl compound component content, hydrogenation rate, etc. are different from each other.

[0063] The styrenic elastomer may be partially hydrogenated or fully hydrogenated. From the viewpoint of suppressing thermal deterioration during processing, the hydrogenation rate of the hydrogenated product is preferably 50% or more, or 80% or more, or 98% or more, and from the viewpoint of low-temperature toughness, it is preferably 50% or less, or 20% or less, or 0% (i.e., non-hydrogenated product). Examples of the hydrogenated product of the conjugated diene polymer include the hydrogenated products of the conjugated diene polymers exemplified above. For example, it may be a hydrogenated product of a styrene-butadiene copolymer.

[0064] In one aspect, the styrenic elastomer is not acid-modified. In one aspect, the styrenic elastomer may be an unmodified product.

[0065] In the conjugated diene polymer, the amount of vinyl bonds in the conjugated diene bond units (e.g., 1,2- or 3,4-bonds of butadiene) is preferably 5 mol% or more, or 10 mol% or more, or 13 mol% or more, or 15 mol% or more, and preferably 80 mol% or less, or 75 mol% or less, or 65 mol% or less, or 50 mol% or less, or 40 mol% or less. The amount of vinyl bonds in the conjugated diene bond units (e.g., the amount of 1,2-bonds of butadiene) 13 can be determined by the 13C-NMR method (quantitative mode). That is, 13 By integrating the peak areas that appear below in 13C-NMR, a value proportional to the amount of carbon in each structural unit can be obtained, and as a result, it can be converted to mass% of each structural unit. Styrene 145 - 147 ppm Vinyl 110 - 116 ppm Diene (cis) 24 - 28 ppm Diene (trans) 29 - 33 ppm

[0066] In the copolymer of a conjugated diene monomer and an aromatic vinyl monomer, the amount of the aromatic vinyl monomer bonded to the conjugated diene monomer (also referred to as the aromatic vinyl bond amount in the present disclosure) may be preferably 5.0 mass% or more and 70 mass% or less, or 10 mass% or more and 50 mass% or less based on the total mass of the styrene-based elastomer. The aromatic vinyl bond amount can be determined by the ultraviolet absorbance of the phenyl group, and based on this, the conjugated diene bond amount can also be determined.

[0067] Styrene-based elastomers are preferably at least one selected from the group consisting of styrene-butadiene block copolymers, styrene-ethylene-butadiene block copolymers, styrene-ethylene-butylene block copolymers, styrene-butadiene-butylene block copolymers, styrene-isoprene block copolymers, styrene-ethylene-propylene block copolymers, styrene-isobutylene block copolymers, hydrogenated products of styrene-butadiene block copolymers, hydrogenated products of styrene-ethylene-butadiene block copolymers, hydrogenated products of styrene-butadiene-butylene block copolymers, hydrogenated products 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, hydrogenated products of styrene-butadiene block copolymers, and polystyrene.

[0068] From the viewpoint of achieving both impact strength and fluidity, the number average molecular weight (Mn) of the styrene-based elastomer is preferably 10,000 to 500,000, or 40,000 to 250,000.

[0069] From the viewpoint of obtaining the good rubber elasticity, weather resistance, and chemical resistance inherent in the styrene-based elastomer, the amount of the styrene-based elastomer relative to 1 part by mass of the cellulose nanofiber is preferably 0.5 part by mass or more, or 1 part by mass or more, or 3 parts by mass or more, or 5 parts by mass or more, or 7 parts by mass or more, or 10 parts by mass or more, or 15 parts by mass or more. From the viewpoint of reducing the tackiness and improving 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.

[0070] The amount of the styrenic elastomer in 100% by mass of the resin composition is preferably 10% by mass or more, or 20% by mass or more, or 40% by mass or more, or 50% by mass or more, or 60% by mass or more, or 70% by mass or more, or 80% by mass or more from the viewpoint of obtaining the advantages inherent to the styrenic elastomer, and is preferably 99.5% by mass or less, or 99% by mass or less, or 98% by mass or less, or 95% by mass or less, or 90% by mass or less from the viewpoint of containing other components in desired amounts.

[0071] The melt mass flow rate (MFR) of the styrenic elastomer at 230 °C and 2.16 kg is preferably 20 g / 10 min or less, or 15 g / 10 min or less, or 10 g / 10 min or less, or 8 g / 10 min or less, or 5 g / 10 min or less from the viewpoint of obtaining good mechanical properties of the resin composition, and is preferably 0.1 g / 10 min or more, or 0.5 g / 10 min or more, or 1.0 g / 10 min or more from the viewpoint of facilitating melt processing.

[0072] <Acid-modified styrenic elastomer> In one aspect, the resin composition contains an acid-modified styrene-based elastomer. In addition to the cellulose nanofibers, the presence of the acid-modified styrene-based elastomer has been found to further improve the tensile strength, tensile modulus, tensile elongation at break, and / or hardness of the molded article, and to reduce disadvantages such as whitening and coloring of the molded article. Without being bound by theory, the interface between the hydroxyl groups of the cellulose nanofibers and the acid-modified groups of the acid-modified styrene-based elastomer is strengthened by the reaction between them, so that when an external force is applied to the molded article, delamination between the styrene-based elastomer, the cellulose nanofibers, and the acid-modified styrene-based elastomer is less likely to occur, and coloring due to thermal degradation of the cellulose nanofibers is less likely to occur. As a result, the effect of improving the physical properties by the cellulose nanofibers is favorably exhibited, generation of voids in the molded article due to delamination is suppressed and whitening is reduced, and furthermore, coloring of the cellulose nanofibers is also suppressed. The presence of the acid-modified styrene-based elastomer in the resin composition is also advantageous in terms of further reducing the tackiness caused by the styrene-based elastomer.

[0073] In the resin composition according to one aspect, the acid-modified styrene-based elastomer and the styrene-based elastomer are compatibilized without phase separation and form a continuous phase. In the resin composition according to one aspect, the acid-modified styrene-based elastomer forms a first phase, and the styrene-based elastomer forms a second phase that is phase-separated from the first phase. In one aspect, in 100% by mass of the resin composition, the total amount of the acid-modified styrene-based elastomer and the styrene-based elastomer is 60% by mass or more. In one aspect, the second phase is a continuous phase. In one aspect, the first phase is a dispersed phase and the second phase is a continuous phase. The dispersed phase may have a domain size of, for example, 20 nm to 10 μm. The domain size can be determined from a scanning electron microscope (SEM) image. Alternatively, in one aspect, each of the first phase and the second phase may be a continuous phase. The phase separation of the acid-modified styrene-based elastomer and the styrene-based elastomer contributes to the expression of the good properties inherent in the styrene-based elastomer in the resin composition, while the acid-modified styrene-based elastomer site in the resin composition is interposed between the styrene-based elastomer and the cellulose nanofiber due to the good affinity with both the styrene-based elastomer and the cellulose nanofiber, contributing to further improvement of the physical property improvement effect by the cellulose nanofiber.

[0074] The acid-modified styrene-based elastomer may be an acid-modified product of the styrene-based elastomer exemplified above. In the present disclosure, the acid-modified styrene-based elastomer means that an acidic functional group is added as an acid-modifying group through a chemical bond in the molecular skeleton of the styrene-based elastomer. Also in the present disclosure, the acidic functional group means a functional group capable of reacting with a basic functional group or the like, and specific examples include a hydroxyl group, a carboxyl group, a carboxylate group, a sulfo group, an acid anhydride group, and the like.

[0075] The acid modification rate, which is the mass ratio of acid modification groups in 100% by mass of the acid-modified styrene-based elastomer, is preferably 0.2% by mass or more, or 0.5% by mass or more, or 0.8% by mass or more, or 1.0% by mass or more, or 1.2% by mass or more, or 1.5% by mass or more based on 100% by mass of the acid-modified styrene-based elastomer from the viewpoint of the affinity with cellulose nanofibers, and is preferably 5.0% by mass or less, or 3.0% by mass or less, or 2.5% by mass or less, or 2.0% by mass or less from the viewpoint of the affinity with the styrene-based elastomer. The acid modification rate is a value obtained by measuring a calibration sample mixed with an acidic substance in advance using an infrared absorption spectrum measuring device and measuring the sample based on a calibration curve prepared using the characteristic absorption band of the acid.

[0076] In a preferred embodiment, the acid-modified styrene-based elastomer is an acid-modified product of an aromatic vinyl compound-conjugated diene compound copolymer (preferably an aromatic vinyl compound-conjugated diene compound block copolymer) or a hydrogenated product thereof, which is a styrene-based elastomer. Examples of such acid-modified styrene-based elastomers include elastomers that are modified products obtained by grafting an α,β-unsaturated dicarboxylic acid or a derivative thereof onto an aromatic compound-conjugated diene copolymer (preferably a block copolymer) or a hydrogenated product thereof in the presence or absence of a peroxide. Specific examples of the α,β-unsaturated dicarboxylic acid and its derivatives include maleic acid, fumaric acid, maleic anhydride, and fumaric anhydride, and maleic anhydride is particularly preferred among these. In a preferred embodiment, the acid-modified styrene-based elastomer is an acid anhydride-modified styrene-based elastomer.

[0077] The acid-modified styrenic elastomer is preferably at least one acid-modified product selected from the group consisting of styrene-butadiene block copolymer, styrene-ethylene-butadiene block copolymer, styrene-ethylene-butylene block copolymer, styrene-butadiene-butylene block copolymer, styrene-isoprene block copolymer, styrene-ethylene-propylene block copolymer, styrene-isobutylene block copolymer, hydrogenated product of styrene-butadiene block copolymer, hydrogenated product of styrene-ethylene-butadiene block copolymer, hydrogenated product of styrene-butadiene-butylene block copolymer, hydrogenated product of styrene-isoprene block copolymer, and homopolymer of styrene (polystyrene). More preferably, it is one or more acid-modified products selected from the group consisting of styrene-butadiene block copolymer, hydrogenated product of styrene-butadiene block copolymer, and polystyrene.

[0078] The styrene unit ratio of the acid-modified styrenic elastomer and the unit ratio of the styrenic elastomer are preferably 10 mol% or more, or 15 mol% or more, or 20 mol% or more, respectively, from the viewpoints of the affinity between the acid-modified styrenic elastomer and the styrenic elastomer, and the favorable expression of the advantageous properties inherent in the styrenic elastomer. From the viewpoint of the flexibility of the composition, they are preferably 40 mol% or less, or 35 mol% or less, or 30 mol% or less, or 25 mol% or less. The styrene unit ratio is a value determined by the NMR method.

[0079] The ratio of the styrene unit ratio of the styrenic elastomer to the styrene unit ratio of the acid-modified styrenic elastomer (styrene ratio of the styrenic elastomer / styrene ratio of the acid-modified styrenic elastomer) is preferably 0.3 or more, or 0.35 or more, or 0.4 or more from the viewpoint of the affinity between the acid-modified styrenic elastomer and the styrenic elastomer. From the same viewpoint, it is preferably 4 or less, or 3 or less, or 2 or less.

[0080] In the acid-modified styrene-based elastomer, the ratio of the styrene unit ratio to the acid modification rate (styrene unit ratio / acid modification rate) is preferably 5 or more, or 8 or more, or 12 or more from the viewpoint of affinity with the styrene-based elastomer, and preferably 90 or less, or 50 or less, or 30 or less from the viewpoint of affinity with cellulose nanofibers.

[0081] The melt mass flow rate (MFR) of the acid-modified styrene-based elastomer at 230 °C and 2.16 kg is preferably 0.1 g / 10 min or more, or 0.5 g / 10 min or more, or 1.0 g / 10 min from the viewpoint of affinity with the styrene-based elastomer, and preferably 20 g / 10 min or less, or 15 g / 10 min or less, or 10 g / 10 min or less, or 8 g / 10 min or less, or 5 g / 10 min or less from the viewpoint of affinity with cellulose nanofibers.

[0082] In 100% by mass of the resin composition, the total amount of the acid-modified styrene-based elastomer and the styrene-based elastomer is, in one aspect, 50% by mass or more, or 60% by mass or more, or 70% by mass or more, or 80% by mass or more. Such a resin composition can exhibit good rubber elasticity, weather resistance, chemical resistance, etc. The above total amount is, in one aspect, 99.5% by mass or less, or 99% by mass or less, or 98% by mass or less, or 95% by mass or less, or 90% by mass or less from the viewpoint of containing a desired amount of other components, particularly cellulose nanofibers.

[0083] The amount of the acid-modified styrene-based elastomer relative to 100 parts by mass of the styrene-based elastomer is preferably 0.5 part by mass or more, or 1 part by mass or more, or 5 part by mass or more from the viewpoint of favorably obtaining the advantages of the acid-modified styrene-based elastomer, and preferably 100 parts by mass or less, or 50 parts by mass or less, or 20 parts by mass or less, or 10 parts by mass or less from the viewpoint of suppressing coloring, shrinkage during molding, and / or hardness reduction caused by a large amount of the acid-modified styrene-based elastomer.

[0084] The amount of the acid-modified styrene-based elastomer relative to 1 part by mass of the cellulose nanofiber is preferably 0.1 part by mass or more, or 0.3 part by mass or more, or 0.5 part by mass or more, or 0.8 part by mass or more from the viewpoint of favorably obtaining the advantages of the acid-modified styrene-based elastomer, and is preferably 45 parts by mass or less, or 30 parts by mass or less, or 20 parts by mass or less, or 10 parts by mass or less, or 5 parts by mass or less, or 3 parts by mass or less, or 2 parts by mass or less from the viewpoint of suppressing coloring, shrinkage during molding, and / or decrease in hardness caused by a large amount of the acid-modified styrene-based elastomer.

[0085] The amount of the acid-modified styrene-based elastomer in 100% by mass of the resin composition is preferably 0.5% by mass or more, or 1% by mass or more, or 2% by mass or more, or 3% by mass or more, or 4% by mass or more from the viewpoint of favorably obtaining the advantages of the acid-modified styrene-based elastomer, and is preferably 50% by mass or less, or 30% by mass or less, or 20% by mass or less, or 10% by mass or less from the viewpoint of suppressing coloring, shrinkage during molding, and / or decrease in hardness caused by a large amount of the acid-modified styrene-based elastomer. Incidentally, the acid-modified styrene-based elastomer is generally relatively expensive, and reducing the amount used is also advantageous in terms of cost.

[0086] <Liquid polymer> In one aspect, the resin composition may contain a liquid polymer. The liquid polymer means a polymer having fluidity at 23°C. In one aspect, the liquid polymer has a glass transition temperature (Tg). In one aspect, the liquid polymer may be a conjugated diene-based polymer or a non-conjugated diene-based polymer. The liquid polymer is a liquid rubber in one aspect. In the present disclosure, the liquid rubber means a substance that has fluidity at 23°C and forms a rubber elastomer by crosslinking (more specifically, vulcanization) and / or chain extension. That is, the liquid rubber is an uncured product in one aspect.

[0087] Also, having fluidity means, in one aspect, that after putting a liquid polymer dissolved in cyclohexane into a vial with a body diameter of 21 mm and a total length of 50 mm at 23°C and then drying it, the liquid polymer is filled into the vial up to a height of 1 mm and sealed, and when the vial is placed upside down and left standing for 24 hours, a movement of a substance of 0.1 mm or more in the height direction can be confirmed.

[0088] The liquid polymer may have a monomer composition of a general polymer, and is preferably of a relatively low molecular weight from the viewpoints of ease of handling and good dispersibility of cellulose nanofibers. In one aspect, the liquid polymer exhibits a liquid shape by having a number average molecular weight (Mn) of 80,000 or less. The number average molecular weight and weight average molecular weight of the various polymers of the present disclosure are values determined in terms of standard polystyrene using gel permeation chromatography with chloroform as a solvent at a measurement temperature of 40°C unless otherwise specified.

[0089] In one aspect, the liquid polymer may be combined with cellulose nanofibers to form a masterbatch, and such a masterbatch may be combined with a resin to form the resin composition of the present disclosure.

[0090] The number average molecular weight (Mn) of the liquid polymer is preferably 1,000 or more, or 1,500 or more, or 2,000 or more from the viewpoints of thermal stability and the effect of improving the dispersibility of cellulose nanofibers in the resin, and is preferably 80,000 or less, or 50,000 or less, or 40,000 or less, or 30,000 or less, or 10,000 or less in terms of having a high fluidity suitable for good dispersion when dispersing cellulose nanofibers in the liquid polymer.

[0091] The weight average molecular weight (Mw) of the liquid polymer is preferably 1,000 or more, or 2,000 or more, or 4,000 or more from the viewpoints of thermal stability and the effect of improving the dispersibility of cellulose nanofibers in the resin, and is preferably 240,000 or less, or 150,000 or less, or 30,000 or less in terms of having high fluidity suitable for good dispersion when dispersing cellulose nanofibers in the liquid polymer.

[0092] The ratio (Mw / Mn) of the number average molecular weight (Mn) to the weight average molecular weight (Mw) of the liquid polymer enables a high degree of compatibility of multiple properties (in one aspect, a high degree of compatibility between good dispersion of cellulose nanofibers in the resin and a good flexural modulus of the resin composition) due to the molecular weight varying to some extent, and is preferably 1.5 or more, or 1.8 or more, or 2 or more. In terms of the point that the variation in molecular weight is not excessively large and the desired physical properties of the resin composition can be stably obtained, for example, in terms of the compatibility between fluidity 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.

[0093] The liquid polymer can have good thermal stability. The thermal decomposition start temperature (T D ) is, in one aspect, above 200°C, or 210°C or higher, or 230°C or higher, or 250°C or higher, or 300°C or higher from the viewpoint of good thermal stability. Although a higher thermal decomposition start temperature is preferred, from the viewpoint of the availability of the liquid polymer, it can be 500°C or less, or 450°C or less, or 400°C or less in one aspect.

[0094] The glass transition temperature of the liquid polymer is preferably -150°C or higher, or -120°C or higher, or -100°C or higher from the viewpoint of good thermal stability, and is preferably 25°C or lower, or 10°C or lower, or 0°C or lower from the viewpoint of good fluidity.

[0095] The liquid polymer, in one aspect, contains a diene polymer and, in one aspect, contains a conjugated diene polymer, a non-conjugated diene polymer, or a hydrogenated product thereof. The above polymer or its hydrogenated product may be an oligomer. The monomers constituting the liquid polymer may be non-modified or modified (e.g., acid-modified, hydroxyl-modified, etc.). In one aspect, the liquid polymer may have reactive groups (e.g., one or more selected from the group consisting of a hydroxyl group, a carboxyl group, an isocyanato group, a thio group, an amino group, and a halo group) at both ends and may thus be bifunctional. These reactive groups contribute to the crosslinking and / or chain extension of the liquid polymer.

[0096] [Conjugated diene polymer] The conjugated diene polymer may be a homopolymer or a copolymer of two or more conjugated diene monomers or a copolymer of a conjugated diene monomer and another monomer. The copolymer may be either random or block.

[0097] Examples of the conjugated diene monomer include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1,3-heptadiene, and 1,3-hexadiene, and these may be used alone or in combination of two or more.

[0098] In one aspect, the conjugated diene polymer is a copolymer of the above conjugated diene monomer and an aromatic vinyl monomer. The aromatic vinyl monomer is not particularly limited as long as it is copolymerizable with the conjugated diene monomer. Examples include styrene, m- or p-methylstyrene, α-methylstyrene, ethylstyrene, p-tert-butylstyrene, vinyl ethylbenzene, vinyl xylene, vinyl naphthalene, diphenylethylene, and divinylbenzene, and these may be used alone or in combination of two or more. From the viewpoints of the moldability of the resin composition and the impact resistance of the molded article, styrene is preferred.

[0099] Examples of the random copolymer include a butadiene-isoprene random copolymer, a butadiene-styrene random copolymer, an isoprene-styrene random copolymer, and a butadiene-isoprene-styrene random copolymer. Examples of the composition distribution of each monomer in the copolymer chain include a perfect random copolymer close to a statistically random composition and a tapered (gradient) random copolymer having a gradient in the composition distribution. The bonding modes of the conjugated diene polymer, that is, the composition of 1,4-bond, 1,2-bond, etc. may be uniform or different among molecules.

[0100] The block copolymer may be a copolymer composed of two or more blocks. For example, it may be a block copolymer in which block A of an aromatic vinyl monomer and block B which is a block of a conjugated diene monomer and / or a copolymer of an aromatic vinyl monomer and a conjugated diene monomer form a structure such as A-B, A-B-A, A-B-A-B. Note that the boundary of each block does not necessarily have to be clearly distinguished. For example, when block B is a copolymer of an aromatic vinyl monomer and a conjugated diene monomer, the aromatic vinyl monomer in block B may be distributed uniformly or in a tapered shape. Further, block B may have a plurality of portions in which the aromatic vinyl monomer is uniformly distributed and / or portions in which the aromatic vinyl monomer is distributed in a tapered shape. Furthermore, block B may have a plurality of segments having different aromatic vinyl monomer contents. When a plurality of block A and block B are present in the copolymer, their molecular weights and compositions may be the same or different.

[0101] The block copolymer may also be a mixture of two or more kinds in which one or more of the bonding form, molecular weight, aromatic vinyl compound species, conjugated diene compound species, 1,2-vinyl content or the total amount of 1,2-vinyl content and 3,4-vinyl content, aromatic vinyl compound component content, hydrogenation rate, etc. are different from each other.

[0102] The amount of vinyl bonds in the conjugated diene bond units in the conjugated diene polymer (for example, 1,2- or 3,4-bond of butadiene) is preferably 10 mol% or more and 75 mol% or less, or 13 mol% or more and 65 mol% or less. The amount of vinyl bonds in the conjugated diene linkage unit (e.g., the 1,2-bond amount of butadiene) can be determined by 13 the 13C-NMR method (quantitative mode). That is, 13 By integrating the peak areas that appear below in 13C-NMR, a value proportional to the amount of carbon in each structural unit can be obtained, and as a result, it can be converted to mass% of each structural unit. Styrene 145 - 147 ppm Vinyl 110 - 116 ppm Diene (cis) 24 - 28 ppm Diene (trans) 29 - 33 ppm

[0103] In the copolymer of a conjugated diene monomer and an aromatic vinyl monomer, the amount of the aromatic vinyl monomer bonded to the conjugated diene monomer (also referred to as the aromatic vinyl bond amount in the present disclosure) may be preferably 5 mol% or more and 70 mol% or less, or 10 mol% or more and 50 mol% or less based on 100% total moles of the conjugated diene polymer.

[0104] Examples of the hydrogenated product of the conjugated diene polymer include the hydrogenated products of the conjugated diene polymers exemplified above. For example, they may be hydrogenated products of butadiene homopolymer, isoprene homopolymer, styrene-butadiene copolymer, and acrylonitrile-butadiene copolymer.

[0105] In a preferred embodiment, the liquid polymer is one or more selected from the group consisting of polybutadiene, butadiene-styrene copolymer, polyisoprene, and polychloroprene. These may be derivatives (e.g., maleic anhydride-modified products, methacrylic acid-modified products, terminal hydroxyl group-modified products, hydrogenated products, and combinations thereof, etc.).

[0106] [Non-conjugated diene polymer] The non-conjugated diene polymer may be a homopolymer, or may be a copolymer of two or more non-conjugated diene monomers or a copolymer of a non-conjugated diene monomer and another monomer. The copolymer may be either random or block. Examples of the non-conjugated diene polymer include olefin polymers (such as liquid paraffin), silicone polymers, acrylic polymers, etc. For example, when the liquid polymer is a liquid rubber, examples of the non-conjugated diene polymer include olefin polymers such as ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-butene-diene rubber, ethylene-α-olefin copolymer, butyl rubber, brominated butyl rubber, acrylic rubber, fluororubber, silicone rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, α,β-unsaturated nitrile-acrylic acid ester-conjugated diene copolymer rubber, urethane rubber, polysulfide rubber, etc.

[0107] In the ethylene-α-olefin copolymer, monomers copolymerizable with ethylene units include aliphatic substituted vinyl monomers such as propylene, butene-1, pentene-1, 4-methylpentene-1, hexene-1, heptene-1, octene-1, nonene-1, decene-1, undecene-1, dodecene-1, tridecene-1, tetradecene-1, pentadecene-1, hexadecene-1, heptadecene-1, octadecene-1, nonadecene-1, or eicosene-1, isobutylene, and aromatic vinyl monomers such as styrene and substituted styrene, ester vinyl monomers such as vinyl acetate, acrylic acid ester, methacrylic acid ester, glycidyl acrylate, glycidyl methacrylate, hydroxyethyl methacrylate, nitrogen-containing vinyl monomers such as acrylamide, allylamine, vinyl-p-aminobenzene, acrylonitrile, and dienes such as butadiene, cyclopentadiene, 1,4-hexadiene, isoprene, etc.

[0108] The ethylene-α-olefin copolymer is preferably a copolymer of ethylene and at least one α-olefin having 3 to 20 carbon atoms, more preferably a copolymer of ethylene and at least one α-olefin having 3 to 16 carbon atoms, and most preferably a copolymer of ethylene and at least one α-olefin having 3 to 12 carbon atoms.

[0109] From the viewpoint of expressing impact resistance, the molecular weight of the ethylene-α-olefin copolymer is preferably 10,000 or more, more preferably 10,000 to 100,000, more preferably 10,000 to 80,000, and still more preferably 20,000 to 60,000, as measured by gel permeation chromatography using 1,2,4-trichlorobenzene as a solvent at 140 °C with polystyrene standards.

[0110] Also, from the viewpoint of handleability during processing, the content of ethylene units in the ethylene-α-olefin copolymer is preferably 30 to 95% by mass based on the total amount of the ethylene-α-olefin copolymer.

[0111] The ethylene-α-olefin copolymer can be produced by a conventionally known production method as described in, for example, Japanese Patent Publication No. 4-12283, Japanese Unexamined Patent Application Publication Nos. 60-35006, 60-35007, 60-35008, 5-155930, 3-163088, and US Patent No. 5272236.

[0112] In one aspect, the liquid polymer contains at least one selected from the group consisting of diene rubbers, silicone rubbers, urethane rubbers, and polysulfide rubbers and hydrogenated products thereof, and preferably contains a diene rubber.

[0113] The viscosity of the liquid polymer at 25°C is preferably 1,000,000 mPa·s or less, or 500,000 mPa·s or less, or 200,000 mPa·s or less, from the viewpoint of favorably dispersing the cellulose nanofibers in the liquid polymer, and is preferably 100 mPa·s or more, or 300 mPa·s or more, or 500 mPa·s or more, from the viewpoints of thermal stability, the effect of improving the dispersibility of the cellulose nanofibers in the resin, and the mechanical properties of the resin composition.

[0114] 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 viewpoints of favorably dispersing the cellulose nanofibers in the liquid polymer and favorably dispersing the cellulose nanofibers in the resin by heat kneading, and is preferably 50 mPa·s or more, or 100 mPa·s or more, or 500 mPa·s or more, from the viewpoints of thermal stability, the effect of improving the dispersibility of the cellulose nanofibers in the resin, and the mechanical properties of the resin composition.

[0115] 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 viewpoints of favorably dispersing the cellulose nanofibers in the liquid polymer and favorably dispersing the cellulose nanofibers in the resin by heat kneading, and is preferably 50 mPa·s or more, or 100 mPa·s or more, or 300 mPa·s or more, from the viewpoints of thermal stability, the effect of improving the dispersibility of the cellulose nanofibers in the resin, and the mechanical properties of the resin composition.

[0116] The viscosity of the liquid polymer at 0 °C is preferably 2,000,000 mPa·s or less, or 1,000,000 mPa·s or less, or 400,000 mPa·s or less, from the viewpoint of well-dispersing the cellulose nanofibers in the liquid polymer, and is preferably 200 mPa·s or more, or 600 mPa·s or more, or 1,000 mPa·s or more, from the viewpoints of thermal stability, the effect of improving the dispersibility of the cellulose nanofibers in the resin, and the mechanical properties of the resin composition.

[0117] It is preferable that the viscosities of the liquid polymer at 80 °C, 50 °C, 25 °C, and 0 °C are all within the above ranges, in that the cellulose nanofibers can be well-dispersed in the liquid polymer over a wide mixing temperature range.

[0118] The viscosity of the liquid polymer is a value measured at a rotational speed of 10 rpm using a B-type viscometer.

[0119] In the resin composition, the amount of the liquid polymer relative to 100 parts by mass of the styrene-based elastomer is preferably 0.1 part by mass or more, or 0.3 part by mass or more, or 0.5 part by mass or more, or 1.0 part by mass or more, from the viewpoint of favorably obtaining the advantages of the liquid polymer, and is preferably 15 parts by mass or less, or 10 parts by mass or less, or 5 parts by mass or less, from the viewpoint of obtaining a resin composition exhibiting the original physical properties of the styrene-based elastomer.

[0120] In the resin composition, the amount of the liquid polymer relative to 100 parts by mass of the cellulose nanofibers is preferably 5 parts by mass or more, or 10 parts by mass or more, or 20 parts by mass or more, or 30 parts by mass or more, or 40 parts by mass or more, from the viewpoint of favorably obtaining the advantages of the liquid polymer, and is preferably 400 parts by mass or less, or 200 parts by mass or less, or 100 parts by mass or less, from the viewpoint of obtaining good physical properties of the resin composition and the resin molded article.

[0121] From the viewpoint of obtaining the advantages of the liquid polymer well, the content of the liquid polymer in the resin composition is preferably 0.1% by mass or more, or 0.3% by mass or more, or 1.0% by mass or more, and from the viewpoint of obtaining good physical properties of the resin composition and 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.

[0122] <Dispersant> In one aspect, the resin composition contains a dispersant. In one aspect, it is more preferable that the dispersant has a hydrophilic segment and a hydrophobic segment in the same molecule (that is, it is an amphiphilic molecule) from the viewpoint of more uniformly dispersing cellulose nanofibers in the resin composition. In a preferred embodiment, the resin composition contains a polymer containing polyoxyethylene units.

[0123] [Amphiphilic molecule] In the amphiphilic molecule, the hydrophilic segment is a part that exhibits good affinity with cellulose nanofibers by including a hydrophilic structure. Specific examples of the hydrophilic structure include hydroxyl group, thiol group, carboxy group, sulfonic acid group, sulfate ester group, phosphate group, boronic acid group, silanol group, groups derived from saccharides such as sorbitan and sucrose, groups derived from glycerin, -OM, -COOM, -SO3M, -OSO3M, -HMPO4, and -M2PO4 (where M represents an alkali metal or an alkaline earth metal), and also have primary to tertiary amines and quaternary ammonium salts. Examples of the counter anion of the above quaternary ammonium salt include halide ions such as hydroxide ion, fluoride ion, chloride ion, bromide ion, iodide ion, and one or more hydrophilic groups selected from the group consisting of nitrate ion, formate ion, acetate ion, trifluoroacetate ion, p-toluenesulfonate ion, hexafluorophosphate, and tetrafluoroborate.

[0124] Examples of the hydrophilic segment include a segment of polyethylene glycol, a segment containing a repeating unit having a quaternary ammonium salt structure, a segment of polyvinyl alcohol, a segment of polyvinyl pyrrolidone, a segment of polyacrylic acid, a segment of carboxyvinyl polymer, a segment of cationized guar gum, a segment of hydroxyethyl cellulose, a segment of methyl cellulose, a segment of carboxymethyl cellulose, a soft segment of polyurethane (specifically, a diol segment), and the like. Nonionic polyoxyethylene derivatives are particularly preferred, and the polyoxyethylene chain length of the polyoxyethylene derivative may be 3 or more, or 5 or more, or 10 or more, or 15 or more. The longer the chain length, the higher the affinity with the cellulose nanofiber, but from the viewpoint of the balance with the desired properties (for example, mechanical properties) of the resin molded body, the polyoxyethylene chain length may be 60 or less, or 50 or less, or 40 or less, or 30 or less, or 20 or less.

[0125] Examples of the hydrophobic segment include a segment having a hydrocarbon, a segment having a fluorocarbon, a segment having an alkylene oxide unit having 3 or more carbon atoms (for example, a PPG block), a segment containing a polymer structure, and the like. Examples of the segment having a hydrocarbon include an alkyl type, an alkenyl type, an alkyl ether type, an alkenyl ether type, an alkyl phenyl ether type, an alkenyl phenyl ether type, a rosin ester type, a bisphenol A type, a β-naphthyl type, a styrenated phenyl type, and a hydrogenated castor oil type, and the like are preferred. The number of carbon atoms of the alkyl chain or alkenyl chain of the hydrophobic group (in the case of alkyl phenyl or alkenyl phenyl, the number of carbon atoms excluding the phenyl group) is preferably 2 or more, or 5 or more, or 10 or more, or 12 or more, or 16 or more. Examples of the segment having a fluorocarbon include a linear or branched alkyl type having 1 to 20 carbon atoms, and the like are preferred. Examples of segments containing a polymer structure include acrylic polymers, styrenic resins, vinyl chloride resins, vinylidene chloride resins, polyolefin resins, amino acid lactams including ring-opening polymers of lactams, polymers composed of diamines and dicarboxylic acids, polyacetal resins, polycarbonate resins, polyester resins, polyphenylene sulfide resins, polysulfone resins, polyether ketone resins, polyimide resins, fluorine resins, hydrophobic silicone resins, melamine resins, epoxy resins, phenolic resins, etc. These hydrophobic segments may have either a linear structure or a branched structure. Further, the hydrophobic segment may have a single-chain structure or a structure of two or more chains. When it has a structure of two or more chains, it may have a plurality of types of hydrophobic groups.

[0126] The structure of the amphiphilic molecule is not particularly limited. 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, a three-branched copolymer containing A and B, a four-branched copolymer containing A and B, a star copolymer containing A and B, a monocyclic copolymer containing A and B, a polycyclic copolymer containing A and B, a cage copolymer containing A and B, a graft copolymer containing A and B, etc. When there are a plurality in the molecule, the molecular structure of the hydrophilic segment may be a single type alone or a combination of two or more types. Similarly, when there are a plurality in the molecule, the molecular structure of the hydrophobic segment may be a single type alone or a combination of two or more types.

[0127] (Surfactant) As the amphiphilic molecule, any of an anionic surfactant, a nonionic surfactant, a cationic surfactant, and an amphoteric surfactant can be used. The dispersant may be a polymer surfactant, a reactive surfactant, etc.

[0128] Examples of nonionic surfactants include fatty acid dialkanolamides (e.g., lauric acid diethanolamide), polyoxyalkylene fatty acid amides (e.g., polyoxyethylene stearic acid amide), polyoxyalkylene aryl ethers (e.g., polyoxyethylene phenyl ether), polyoxyalkylene alkylaryl ethers (e.g., polyoxyethylene octylphenyl ether), polyoxyalkylene alkyl or alkenyl ethers (e.g., polyoxyethylene lauryl ether, polyoxyethylene stearyl ether), fatty acid esters of polyhydric alcohols (e.g., polyethylene glycol mono- or distearate, polyethylene glycol mono- or dilaurate, polyoxyethylene hydrogenated castor oil), glycerin fatty acid esters (e.g., glycerin monostearate, glycerin monooleate), sorbitan fatty acid esters (e.g., sorbitan monolaurate, sorbitan monostearate), polyoxyethylene-polyoxypropylene block polymers, and the like.

[0129] Anionic surfactants (emulsifiers) may be carboxylates, sulfonates, sulfate esters, phosphate esters, etc. Examples include, as carboxylates, aliphatic monocarboxylic acids, alkyl ether carboxylates; as sulfonates, dialkyl sulfosuccinates, alkane sulfonates, alkylbenzene sulfonates, alkylnaphthalene sulfonates; as sulfate esters, alkyl sulfates, fatty oil sulfate esters; and as phosphate esters, alkyl phosphates, polyoxyethylene alkyl ether phosphates.

[0130] Examples of cationic surfactants include amine salts, amidoamine salts, quaternary ammonium salts, and imidazolinium salts. Specific examples include, but are not limited to, amine salt-type surfactants such as alkylamine salts, polyoxyethylene alkylamine salts, alkylamidoamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, and imidazolines; quaternary ammonium salt-type surfactants such as alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, alkylpyridinium salts, alkylisoquinolinium salts, and benzethonium chloride.

[0131] Examples of amphoteric surfactants include, for example, alkylamine oxides, alanines, imidazolinium betaines, amidobetaines, betaine acetates, etc. Specifically, long-chain amine oxides, lauryl betaine, stearyl betaine, lauryl carboxymethyl hydroxyethyl imidazolinium betaine, lauryl dimethylaminoacetate betaine, fatty acid amide propyl dimethylaminoacetate betaine, etc. can be mentioned.

[0132] [Hydrophilic polymer] In one aspect, the dispersant is preferably a hydrophilic polymer. In one aspect, the hydrophilic polymer is a polymer having a hydrophilic group selected from the group consisting of a hydroxyl group, a carboxy group, an amino group, an ammonium group, a sulfonic acid group, a phosphoric acid group, etc. As the hydrophilic polymer, one or more selected from the group consisting of cellulose derivatives (hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, etc.), polyalkylene glycols, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, carboxyvinyl polymer, cationized guar gum, water-soluble polyurethane, polymers containing a quaternary ammonium salt structure, amides, amines, etc. can be used. Among them, cellulose derivatives and polyalkylene glycols are more preferable, and polyalkylene glycols are particularly preferable.

[0133] The amount of the dispersant in the resin composition is preferably 1 part by mass or more, or 3 parts by mass or more, or 5 parts by mass or more, or 10 parts by mass or more, or 15 parts by mass or more, based on 100 parts by mass of the cellulose nanofiber, and is preferably 200 parts by mass or less, or 150 parts by mass or less, or 100 parts by mass or less, or 90 parts by mass or less, or 80 parts by mass or less, or 70 parts by mass or less, or 60 parts by mass or less, or 50 parts by mass or less.

[0134] In one aspect, the content of the dispersant in the resin composition component may be 0.1% by mass or more, or 0.5% by mass or more, or 1% by mass or more, and in one aspect, may be 40% by mass or less, or 35% by mass or less, or 30% by mass or less.

[0135] For example, when a preliminary composition containing cellulose nanofiber and an acid-modified styrene-based elastomer is used for the production of the resin composition, the mass ratio (preliminary composition / styrene-based elastomer) of the preliminary composition and the styrene-based elastomer in the resin composition component may 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 in one aspect.

[0136] In the resin composition component, the content of the styrene-based elastomer is preferably 10% by mass or more, or 20% by mass or more, and is preferably 90% by mass or less, or 85% by mass or less, or 80% by mass or less.

[0137] In the resin composition component, the total content of the styrene-based elastomer and the acid-modified styrene-based elastomer is preferably 40% by mass or more, or 45% by mass or more, or 50% by mass or more, and is preferably 99% by mass or less, or 95% by mass or less, or 90% by mass or less.

[0138] In the resin composition component, the content of the acid-modified styrene-based elastomer with respect to a total of 100 parts by mass of the styrene-based elastomer and the acid-modified styrene-based elastomer is preferably 5 parts by mass or more, or 10 parts by mass or more, or 15 parts by mass or more, and preferably 70 parts by mass or less, or 65 parts by mass or less, or 60 parts by mass or less.

[0139] The amount of cellulose nanofibers in the resin composition component is preferably 1 part by mass or more, or 2 parts by mass or more, or 3 parts by mass or more with respect to a total of 100 parts by mass of the styrene-based elastomer and the acid-modified styrene-based elastomer, and preferably 70 parts by mass or less, or 65 parts by mass or less, or 60 parts by mass or less.

[0140] The mass ratio of [cellulose nanofibers] / [total of styrene-based elastomer and acid-modified styrene-based elastomer] in the resin composition component is preferably 1 / 99 to 60 / 40, or 2 / 98 to 50 / 50, or 3 / 97 to 40 / 60.

[0141] [Vulcanizing agent, vulcanization accelerator] When the resin composition component contains a liquid rubber, the resin composition component typically contains a vulcanizing agent and may optionally contain a vulcanization accelerator. As the vulcanizing agent and the vulcanization accelerator, conventionally known ones may be appropriately selected according to the type of the liquid rubber in the resin composition component. As the vulcanizing agent, organic peroxides, azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur, sulfur compounds, etc. can be used. Examples of the sulfur compound include sulfur monochloride, sulfur dichloride, disulfide compounds, high molecular polysulfur compounds, etc.

[0142] The amount of the vulcanizing agent in the resin composition component is preferably 0.01 part by mass to 20 parts by mass, or 0.1 part by mass to 15 parts by mass with respect to 100 parts by mass of the liquid rubber in the resin composition component.

[0143] Examples of the vulcanization accelerator include vulcanization accelerators such as sulfenamide-based, guanidine-based, thiuram-based, aldehyde-amine-based, aldehyde-ammonia-based, thiazole-based, thiourea-based, and dithiocarbamate-based vulcanization accelerators. Zinc white, stearic acid, etc. may be used as a vulcanization aid. The amount of the vulcanization accelerator is preferably 0.01 parts by mass to 20 parts by mass, or 0.1 parts by mass to 15 parts by mass with respect to 100 parts by mass of the liquid rubber in the resin composition component.

[0144] [Additives for rubber] The resin composition component may contain various conventionally known additives for rubber (stabilizers, softeners, anti-aging agents, etc.). As the rubber stabilizer, one or more antioxidants such as 2,6-di-tert-butyl-4-hydroxytoluene (BHT), n-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenyl) propionate, and 2-methyl-4,6-bis[(octylthio)methyl]phenol may be used. Also, as the rubber softener, one or more of process oil, extender oil, etc. may be used. However, the resin composition of the present embodiment can form a flexible molded body in one aspect, and thus the resin composition component can not contain a rubber softener in one aspect.

[0145] Note that the vulcanizing agent, vulcanization accelerator, and additives for rubber are typically added during the production of the resin composition, but the mode of addition is not limited thereto.

[0146] [Additional components of the resin composition component] The resin composition component may further contain additional components. Examples of the additional components include additional polymers, organic or inorganic fillers, heat stabilizers, antioxidants, antistatic agents, colorants, etc. The content ratio of any additional component in the resin composition component is appropriately selected within a range that does not impair the desired effects of the present invention, and may be, for example, 0.01 to 50% by mass, or 0.1 to 30% by mass.

[0147] [Production of the resin composition] The resin composition can be produced by a method of mixing composition components which is a mixture containing a tack inhibitor containing cellulose nanofibers and a styrene-based elastomer. The mixing is heat kneading in one aspect. That is, the method for producing a resin composition according to one aspect includes a kneading step of heat kneading a mixture containing a styrene-based elastomer and cellulose nanofibers.

[0148] The weight increase rate of the cellulose nanofibers after heat kneading with respect to the cellulose nanofibers before heat kneading is preferably 150% or more and 600% or less. From the viewpoint of the interfacial strength between the resin and the cellulose nanofibers, the weight increase rate is preferably 150% or more, or 170% or more, or 190% or more, and from the viewpoint of suppressing short fiber formation during kneading, it is preferably 600% or less, or 500% or less, or 400% or less. The weight increase rate is a value measured by the method described in the [Examples] section of the present disclosure.

[0149] As an example of the method for producing the resin composition, when an acid-modified styrene-based elastomer is further used, (1) a first step of mixing cellulose nanofibers and an acid-modified styrene-based elastomer to obtain a preliminary composition, and a second step of mixing the preliminary composition and a styrene-based elastomer to obtain a resin composition, (2) a method including a step of batch mixing resin composition components containing cellulose nanofibers, a styrene-based elastomer, and an acid-modified styrene-based elastomer, etc. can be mentioned. When an acid-modified styrene-based elastomer is not used, the resin composition components containing cellulose nanofibers and a styrene-based elastomer may be batch mixed in the method of (2) above. The mixing conditions are not particularly limited. For example, the components constituting the resin composition may be mixed by stirring means such as a rotating and revolving mixer, a planetary mixer, a propeller-type stirrer, a rotary stirrer, an electromagnetic stirrer, an open roll, a Banbury mixer, a kneader, a single-screw extruder, a twin-screw extruder, etc. to obtain a resin composition. Also, stirring may be performed under heating in order to efficiently perform shearing. In the method of (1) above, by previously combining an acid-modified styrene-based elastomer with cellulose nanofibers, the contact opportunity between the cellulose nanofibers and the styrene-based elastomer becomes more appropriate and uniform, so that the improvement of the physical properties of the resin composition can be better.

[0150] The cellulose nanofibers used for mixing with the acid-modified styrene-based elastomer or the styrene-based elastomer may be in the form of a dried product containing cellulose nanofibers. In one aspect, the cellulose nanofibers may be mixed with a liquid polymer and / or a dispersant in the form of a slurry, and the contained liquid medium may be dried and removed to obtain a dried product containing cellulose nanofibers. The drying process in this case can be carried out, for example, as follows.

[0151] [Drying Process] In one aspect, a dried product containing cellulose nanofibers can be produced by drying a cellulose nanofiber slurry. The dryer is not particularly limited, and examples include a kneader, a planetary mixer, a Henschel mixer, a high-speed mixer, a propeller mixer, a ribbon mixer, a single-screw or twin-screw extruder, a Banbury mixer, a freeze dryer, a shelf dryer, a spray dryer, a fluidized bed dryer, a drum dryer, and the like.

[0152] From the viewpoints of drying efficiency, the nano-dispersibility of cellulose nanofibers in the resin composition, and forming a dried product containing cellulose nanofibers with excellent powder properties in terms of macro-dispersibility, the drying temperature may be, for example, 20°C or higher, or 30°C or higher, or 40°C or higher, or 50°C or higher. From the viewpoints of making it difficult to cause thermal degradation of cellulose nanofibers and additional components, and avoiding excessive pulverization of the dried product containing cellulose nanofibers due to rapid drying of the slurry, the drying temperature may be, for example, 200°C or lower, or 180°C or lower, or 160°C or lower, or 140°C or lower, or 120°C or lower, or 100°C or lower. The drying temperature is the temperature of the heat source in contact with the slurry, and is defined, for example, as the surface temperature of the temperature control jacket of the drying apparatus, the surface temperature of the heating cylinder, or the temperature of the hot air.

[0153] The pressure may be either atmospheric pressure or reduced pressure. From the viewpoint of forming a dried product containing cellulose nanofibers with excellent powder properties in terms of drying efficiency, nano-dispersibility, and macro-dispersibility of the cellulose nanofibers in the resin composition, it may be -1 kPa or less, or -10 kPa or less, or -20 kPa or less, or -30 kPa or less, or -40 kPa or less, or -50 kPa or less. From the viewpoint of avoiding excessive pulverization of the dried product containing cellulose nanofibers due to rapid drying of the slurry, it may be -100 kPa or more, or -95 kPa or more, or -90 kPa or more.

[0154] The concentration of cellulose nanofibers in the cellulose nanofiber slurry to be subjected to the drying process is preferably 1% by mass or more, or 2% by mass or more, or 3% by mass or more, or 5% by mass or more, or 10% by mass or more, or 15% by mass or more, or 20% by mass or more, or 25% by mass or more from the viewpoint of process efficiency during drying. From the viewpoint of avoiding excessive increase in the viscosity of the slurry and solidification due to aggregation and maintaining good handleability, 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 production of cellulose nanofibers is often carried out in a dilute dispersion, but the concentration of cellulose nanofibers in the slurry may be adjusted to the preferred range by concentrating such a dilute dispersion. Methods such as suction filtration, pressure filtration, centrifugal dewatering, and heating can be used for concentration.

[0155] In one aspect, the dried product containing cellulose nanofibers may contain a liquid polymer and / or a dispersant, and may be added before, during, and / or after drying of the cellulose nanofiber slurry. In one aspect, the liquid polymer and / or the dispersant may be added in a state of being dispersed or dissolved in water and / or an organic solvent. The organic solvent is not particularly limited, but a solvent in which the liquid polymer and the dispersant are soluble is preferable, and examples thereof include water-insoluble solvents such as chloroform, toluene, hexane, and cyclohexane.

[0156] [Liquid medium content] From the viewpoint of workability during kneading with an acid-modified styrene-based elastomer or a styrene-based elastomer, the liquid medium content of the dry 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. Particularly preferred liquid medium contents from the viewpoint of the tack suppression effect are 7% by mass or less, or 5% by mass or less, or 3% by mass or less. The liquid medium content may be 0% by mass, but from the viewpoint of ease of manufacturing the dry body containing cellulose nanofibers, it may be, for example, 0.1% by mass or more, or 1% by mass or more, or 1.5% by mass or more. The liquid medium content is a value measured using an infrared heating type moisture meter.

[0157] [Average particle size] In one aspect, from the viewpoint of ease of manufacturing, the average particle size of the dry 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, and 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 in terms of the dry body containing cellulose nanofibers being easily disintegrated in the resin composition and the cellulose nanofibers being well dispersed in the resin composition. The above average particle size is a value measured by a dynamic image analysis type particle size distribution measuring device (CAMSIZER X2 manufactured by Microtrac).

[0158] [Loose bulk density] In one aspect, the bulk density of the dry body containing cellulose nanofibers is preferably 0.01 g / cm 3 or more, or 0.05 g / cm 3 or more, or 0.10 g / cm 3 or more, or 0.15 g / cm 3 or more, or 0.20 g / cm 3 or more, or 0.25 g / cm 3 or more, or 0.30 g / cm 3 or more, or 0.35 g / cm 3 or more, or 0.40 g / cm 3 or more, or 0.45 g / cm 3 or more, or 0.50 g / cm 3 or more, and in terms of the dry body containing cellulose nanofibers being easily disintegrated in the resin composition so that the cellulose nanofibers can be well dispersed in the resin composition, and the dry body containing cellulose nanofibers not being too heavy to avoid poor mixing of the dry body containing cellulose nanofibers and the resin composition, preferably 0.85 g / cm 3 or less, or 0.80 g / cm 3 or less, or 0.75 g / cm 3 or less.

[0159] [Bulk density] In one aspect, the bulk density of the dry body containing cellulose nanofibers is controlled within a range useful for controlling the bulk density and compressibility within the scope of the present disclosure. In one aspect, preferably 0.01 g / cm 3 or more, or 0.1 g / cm 3 or more, or 0.15 g / cm 3 or more, or 0.2 g / cm 3 or more, or 0.3 g / cm 3 or more, or 0.4 g / cm 3 or more, or 0.5 g / cm 3 or more, or 0.6 g / cm 3 or more, and preferably 0.95 g / cm 3 or less, or 0.9 g / cm3 or less than 0.85 g / cm 3 or less.

[0160] [Degree of Compression] The degree of compression is a value calculated by Degree of compression = (compressed bulk density - loose bulk density) / compressed bulk density. The loose bulk density and the compressed bulk density are values measured by the method described in the [Examples] section of the present disclosure. In one aspect, the degree of compression represents the degree of compaction. In one aspect, the degree of compression of the dry 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 in that the fluidity of the dry body containing cellulose nanofibers is not too high. Also, in terms of the good fluidity and excellent feedability of the dry body containing cellulose nanofibers, and excellent handleability (specifically, less likely to cause scattering, floating, or dust formation), and in terms of favorably dispersing the dry body containing cellulose nanofibers in the resin composition and suppressing the migration of the dispersant to the resin, the degree of compression is preferably 50% or less, or 45% or less, or 40% or less, or 35% or less, or 30% or less.

[0161] The above loose bulk density, compressed bulk density, and degree of compression are measured using a Powder Tester (model number: PT-X) manufactured by Hosokawa Micron Corporation. The number of tapping times for measuring the compressed bulk density is 180 times.

[0162] As a more specific process sequence, examples when using an acid-modified styrene-based elastomer can be as follows. (i) Prepare a slurry containing cellulose nanofibers and optionally a liquid polymer and / or a dispersant → Dry to prepare a dry body → Prepare a preliminary composition containing the dry body and an acid-modified styrene-based elastomer → Prepare a resin composition containing the preliminary composition and a styrene-based elastomer (ii) Prepare a slurry containing cellulose nanofibers and optionally a liquid polymer and / or a dispersant → Dry to prepare a dried body → Prepare a preliminary composition containing the dried body, an acid-modified styrene-based elastomer, and a styrene-based elastomer → Prepare a resin composition containing the preliminary composition and a styrene-based elastomer (iii) Prepare a slurry containing cellulose nanofibers and optionally a liquid polymer and / or a dispersant → Dry to prepare a dried body → Prepare a resin composition containing the dried body, an acid-modified styrene-based elastomer, and a styrene-based elastomer (iv) Prepare a slurry containing cellulose nanofibers, an acid-modified styrene-based elastomer, and optionally a liquid polymer and / or a dispersant → Dry to prepare a dried body → Prepare a resin composition containing the dried body and a styrene-based elastomer (v) Prepare a slurry containing cellulose nanofibers, an acid-modified styrene-based elastomer, a styrene-based elastomer, and optionally a liquid polymer and / or a dispersant → Dry to prepare a resin composition

[0163] A desired molded article may be produced by molding the resin composition alone or together with other components into a desired shape. The method of combining the compounding components and the molding method are not particularly limited and may be selected according to the desired molded article. The molding is usually melt molding and may be carried out by injection molding, extrusion molding, profile extrusion molding, blow molding, compression molding, etc.

[0164] In one aspect, the molding method may be profile extrusion molding. That is, in one aspect, the resin molded article of the present embodiment may be a profile extrusion molded article. One aspect of the present invention also provides a method for manufacturing a profile extrusion molded article, including the step of profile extruding the resin composition of the present embodiment. Known methods can be used for profile extrusion molding. Specific examples of the profile extrusion molding method include charging the resin composition into an extrusion molding machine, kneading while heating inside, extruding from a die for profile extrusion to obtain an uncooled resin molded article. Then, a method of continuously guiding the uncooled resin molded article to a cooling zone and cooling it to obtain a profile extrusion molded article can be mentioned.

[0165] Also, there is a method in which melt kneading is performed to obtain a resin composition, the die of the kneader is used as a die for profile extrusion to extrude and obtain an uncooled resin molded body, and then the uncooled resin molded body is continuously guided to a cooling zone and cooled to obtain a profile extrusion molded product.

[0166] The lower limit value of the extrusion temperature during profile extrusion is preferably +5°C, more preferably +10°C, relative to the melting point in the case where the thermoplastic resin in the resin composition is a crystalline resin, or relative to the glass transition point in the case of an amorphous resin. By controlling the lower limit value within this range, the productivity of profile extrusion can be improved. The upper limit value of the extrusion temperature during profile extrusion is preferably +100°C, preferably +80°C, preferably +70°C, preferably +60°C, relative to the melting point in the case where the thermoplastic resin in the resin composition is a crystalline resin, or relative to the glass transition point in the case of an amorphous resin. By controlling the upper limit value within this range, deterioration of the cellulose microfibers can be suppressed, so that the mechanical properties of the resin composition can be maintained, and drawdown of the resin between the profile extrusion die and the cooling zone can be suppressed, resulting in good dimensional accuracy of the profile extrusion molded product.

[0167] The profile extrusion molded product is not particularly limited in terms of cross-sectional shape, but as the cross-sectional shape, a sheet shape, a pipe shape, a tube shape, an angular shape, etc. are preferable. In the case of a sheet shape, the sheet thickness can be 0.2 to 50 mm and the sheet width can be 10 to 1500 mm. In the case of a pipe shape or a tube shape, the thickness can be 0.1 to 30 mm and the inner diameter can be 1 to 1000 mm. In the case of an angular shape, the angle of the corner portion can be 30 to 150 degrees. Also, the minimum curvature radius on the valley side of the corner portion can be 0.1 mm.

[0168] <3D printing shaping material> A preferred example of the use of the resin composition of this embodiment is a molding material for 3D printing. One aspect of the present invention provides a molding material for 3D printing composed of the resin composition of this embodiment. The molding material for 3D printing may be formed into a desired form selected from various forms such as pellets, filaments, powders, etc. In one aspect, the molding material for 3D printing has the form of a filament or a powder.

[0169] The molding material for 3D printing of this embodiment is advantageous in that it suppresses dripping (drawdown) due to its own weight from the nozzle during molding or during shaping, due to its ability to suppress cellulose nanofiber aggregation.

[0170] As a method for forming the resin composition into a molding material for 3D printing in a desired form, a known method can be used. For example, the filament may be a monofilament or a multifilament, but a monofilament is preferred for ease of molding.

[0171] The diameter of the filamentous molding material is preferably 0.5 to 5.0 mm, more preferably 1.0 to 3.5 mm, and most preferably 1.5 to 3.0 mm. The length of the filamentous molding material is preferably more than 1 m, more preferably more than 10 m, still more preferably more than 100 m, and most preferably more than 300 m. By controlling the shape of the filamentous molding material within this range, a wide range of applicable 3D printers can be selected, and the molding time, the size and delicacy of the molded object can be appropriately designed. In one aspect, the length of the filamentous molding material may be 20000 m or less.

[0172] In one embodiment, the filament-shaped shaping material can be produced by heating and melting the resin composition, passing it through a fine hole such as a nozzle, cooling it, and winding it up. The diameter of the fine hole can be appropriately selected according to the diameter of the filament and the winding speed, but from the viewpoint of production efficiency and the frequency of occurrence of thread breakage, it is preferably 0.5 to 10.0 mm, more preferably 0.8 to 5.0 mm, and most preferably 1.0 to 3.0 mm. As a cooling method, a known method such as air cooling or water cooling can be appropriately selected, but air cooling is preferred from the viewpoint of preventing water absorption due to the hydrophilicity of cellulose nanofibers. The winding speed of the filament is preferably 0.1 to 10 m / sec, more preferably 0.15 to 5 m / sec, and most preferably 0.2 to 1 m / sec, from the viewpoint of production efficiency and the frequency of occurrence of thread breakage. The manufacturing device for the filament-shaped shaping material and the manufacturing device for the resin composition may be the same or different.

[0173] The particle size, particle shape, and aspect ratio of the powdered modeling material can be appropriately selected according to the 3D printer used. In one embodiment, the particle size is preferably 1 to 10,000 μm, more preferably 10 to 500 μm, and most preferably 30 to 200 μm, from the viewpoint of handling as a modeling material and surface smoothness of the modeled object. The particle shape may be spherical or irregular, but irregular shape is preferable from the viewpoint of suppressing voids during modeling. The aspect ratio is preferably 1.001 to 3.0, preferably 1.01 to 2.0, and most preferably 1.1 to 1.8, from the viewpoint of suppressing voids by reducing interparticle gaps.

[0174] In one embodiment, the powdered modeling material can be produced by pulverizing or reprecipitating the resin composition. The method for pulverizing the resin composition is not particularly limited, and may be wet pulverization, dry pulverization, low-temperature pulverization, freeze pulverization, heat pulverization, etc. A pulverizing medium may be used for the purpose of controlling the shape of the powdered modeling material.

[0175] <Sculpture> One aspect of the present invention provides a shaped article formed by shaping the resin composition (e.g., resin composition pellets) or the molding material for 3D printing of the present embodiment using a 3D printer. One aspect of the present invention also provides a method for manufacturing a shaped article, including the step of shaping the resin composition or the molding material for 3D printing of the present embodiment using a 3D printer. Examples of the shaping method of the 3D printer include a fused deposition modeling method, a stereolithography method, a material jetting method, a powder bonding method, a powder bed fusion method, etc. When using a filamentous molding material, the fused deposition modeling method is preferred, and when using a powdery molding material, the powder bonding method and the powder bed fusion method are preferred.

[0176] <Uses of the Molding Material and Shaped Article for 3D Printing> The shaped article may be directly applied to various uses, or a desired molded product may be manufactured by molding it into a desired shape alone or together with other components. The method of combining the components and the molding method are not particularly limited and may be selected according to the desired molded product. Examples of the molding method include, but are not limited to, a cutting molding method, a foam molding method, etc. The shaped article or the molded product is useful as an alternative to a steel plate, a fiber-reinforced plastic (e.g., carbon fiber-reinforced plastic, glass fiber-reinforced plastic, etc.), a resin composite containing an inorganic filler, etc. Suitable uses of the molding material for 3D printing, the shaped article, or the molded product include industrial machine parts, general machine parts, parts related to automobiles, railways, vehicles, ships, and aerospace, electronic and electrical parts, building and civil engineering materials, daily necessities, sports and leisure goods, housing members for wind power generation, container and packaging members, etc.

[0177] The obtained molded product can be used for various purposes such as automobile parts, electrical and electronic parts, building materials, parts related to daily life, cosmetics, and medical use, rails, pipes, sashes, door frames, window frames, handrails, deck materials, fences, and various building materials.

[0178] Specifically, as automotive parts, there are interior parts such as inner handles, fuel tank openers, seat belt buckles, assist straps, various switches, knobs, levers, clips, etc., electrical system parts such as meters, connectors, etc., in-vehicle electrical and electronic parts such as audio equipment, car navigation equipment, etc., parts that come into contact with metal, represented by the carrier plate of a window regulator, mechanism parts such as door lock actuator parts, mirror parts, wiper motor system parts, parts of the fuel system, etc.

[0179] As electrical and electronic parts, there are parts or members of equipment composed of a resin molded body and having a large number of metal contacts, for example, parts or members of audio equipment, video equipment, or OA equipment such as telephones, copiers, facsimiles, word processors, computers, etc., parts or members of toys, specifically, chassis, gears, levers, cams, pulleys, bearings, etc.

[0180] Furthermore, it is preferably used for a wide range of parts related to daily life, cosmetics, and medicine, such as building materials and piping parts like lighting fixtures, building hardware, piping, cocks, faucets, toilet peripheral equipment parts, fasteners, stationery, lipstick and lip cream containers, cleaners, water purifiers, spray nozzles, spray containers, aerosol containers, general containers, holders for injection needles, etc.

[0181] Among these, it can be more preferably used for gears, which are applications placed in a high-temperature environment and subjected to a high load.

[0182] The tensile stress (modulus) (M100) at 100% elongation of the resin composition or resin molded body may be 2.0 MPa or more, or 3.0 MPa or more, or 4.0 MPa or more in one aspect, and may be 10.0 MPa or less, or 9.0 MPa or less, or 8.0 MPa or less in one aspect.

[0183] The tensile stress at 300% elongation (M300) of the resin composition or resin molded body may be 3.0 MPa or more, or 5.0 MPa or more, or 6.0 MPa or more in one aspect, and may be 20.0 MPa or less, or 15.0 MPa or less, or 13.0 MPa or less in one aspect.

[0184] The ratio (M300 / M100) of the tensile stress at 300% elongation (M300) to the tensile stress at 100% elongation (M100) of the resin composition or resin molded body may be 1.3 or more, or 1.4 or more, or 1.5 or more in one aspect, and may be 2.0 or less, or 1.8 or less in one aspect.

[0185] The storage modulus of the resin composition or resin molded body may be 2.0 MPa or more, or 2.5 MPa or more in one aspect, and may be 4.0 MPa or less, or 3.5 MPa or less, or 3.0 MPa or less in one aspect.

[0186] The loss tangent of the resin composition or resin molded body may be 0.18 or less, or 0.15 or less, or 0.10 or less in one aspect, and may be 0.02 or more, or 0.03 or more, or 0.04 or more in one aspect. The above storage modulus and loss tangent are values measured at 50 °C and 10 Hz in a torsional mode using a rheometer.

[0187] ≪Resin Molded Body≫ One aspect of the present invention provides a resin molded article formed by molding the resin composition of the present embodiment. The resin molded article may have various shapes. The molded article can be used in a wide range of applications such as industrial machine parts, general machine parts, automotive, railway, vehicle, ship, and aerospace-related parts, electronic and electrical parts, building and civil engineering materials, daily necessities, sports and leisure goods, housing members for wind power generation, container and packaging members, etc. Examples of applications include automotive parts (e.g., exterior parts such as tires, bumpers, fenders, door panels, various moldings, emblems, engine hoods, wheel caps, roofs, spoilers, various aerodynamic parts, etc., and interior parts such as instrument panels, console boxes, trims, etc.), battery parts (in-vehicle secondary battery parts, lithium-ion secondary battery parts, fuel cases for solid methanol fuel cells, pipes for fuel cells, etc.), electronic and electrical equipment parts (e.g., various computers and their peripheral devices, junction boxes, various connectors, various office automation equipment, TVs, videos, disc players, chassis, refrigerators, air conditioners, parts of liquid crystal projectors, etc.), daily necessities (such as shoe outsoles, etc.), anti-vibration rubber, conveyor belts, etc., which may be formed as molded products.

Examples

[0188] Hereinafter, exemplary embodiments of the present invention will be further described with reference to examples, but the present invention is not limited to these examples at all.

[0189] ≪Evaluation Method≫ <Acid-modified styrene-based elastomer and styrene-based elastomer> [Acid modification rate (maleinization rate)] The values shown in the product catalog were indicated.

[0190] [Styrene unit ratio] The values shown in the product catalog were indicated.

[0191] [MFR at 230 °C and 2.16 kg] The values shown in the product catalog were indicated.

[0192] <Liquid polymer> [Viscosity at 25 °C] The viscosity of the rubber was measured using a B-type viscometer.

[0193] <Cellulose nanofiber> The following evaluations were performed on the cellulose nanofiber. [Production of Porous Sheet] First, the concentrated cake was added to tert-butanol, and further dispersion treatment was performed with a mixer or the like until there were no aggregates. It was adjusted so that the concentration was 0.5 mass% with respect to 0.5 g of the solid content weight of the cellulose nanofiber. 100 g of the obtained tert-butanol dispersion was filtered on filter paper. Without peeling the filtrate from the filter paper, it was sandwiched between two larger filter papers, and while pressing the edges of the larger filter paper with weights, it was dried in an oven at 150 °C for 5 minutes. Then, the filter paper was peeled off to obtain a porous sheet with little distortion. A porous sheet having an air permeability resistance of 100 sec / 100 ml or less per sheet basis weight of 10 g / m 2 was used as the porous sheet and as the measurement sample. The basis weight W (g / m 2 ) of the sample left standing for 1 day in an environment of 23 °C and 50% RH was measured, and then the air permeability resistance R (sec / 100 ml) was measured using a King Research type air permeability resistance tester (manufactured by Asahi Seiko Co., Ltd., model EG01). At this time, according to the following formula, the value per 10 g / m 2 of the basis weight was calculated. Air permeability resistance per 10 g / m 2 of the basis weight (sec / 100 ml) = R / W × 10

[0194] [Weight-average molecular weight (Mw), number-average molecular weight (Mn), and Mw / Mn ratio] Weighed 0.88 g of the porous sheet, cut it into small pieces with scissors, gently stirred it, added 20 mL of pure water, left it for one day, then separated the water and solid content by centrifugation. Subsequently, added 20 mL of acetone, gently stirred it, and left it for one day. Next, separated the acetone and solid content by centrifugation. Subsequently, added 20 mL of N,N-dimethylacetamide, gently stirred it, and left it for one day. Again, after separating the N,N-dimethylacetamide and solid content by centrifugation, added 20 mL of N,N-dimethylacetamide, gently stirred it, and left it for one day. Separated the N,N-dimethylacetamide and solid content by centrifugation, and added 19.2 g of an N,N-dimethylacetamide solution adjusted so that the lithium chloride in the solid content was 8 mass percent, stirred it with a stirrer, and visually confirmed that it dissolved. The solution in which the cellulose nanofibers were dissolved was filtered through a 0.45 μm filter, and the filtrate was used as a sample for gel permeation chromatography. The apparatus and measurement conditions used are as follows. Apparatus: Tosoh Corporation HLC-8120 Column: TSKgel SuperAWM-H (6.0 mm I.D.×15 cm)×2 columns Detector: RI detector Eluent: N,N-dimethylacetamide (0.2% lithium chloride) Flow rate: 0.6 mL / min Calibration curve: Pullulan conversion

[0195] [Average content rate of alkali-soluble polysaccharides] The alkali-soluble polysaccharide content rate was determined by subtracting the α-cellulose content rate from the holocellulose content rate (Wise method) according to the method described in the non-patent literature (Wood Science Experiment Manual, edited by the Japanese Wood Research Society, pages 92-97, 2000) for cellulose nanofibers. The alkali-soluble polysaccharide content rate was calculated three times for one sample, and the number average of the calculated alkali-soluble polysaccharide content rates was taken as the average content rate of alkali-soluble polysaccharides of the cellulose nanofibers.

[0196] [Average content rate of acid-insoluble components] Quantification of the acid-insoluble component was performed by the Klason method described in a non-patent document (Wood Science Experiment Manual, edited by the Japan Wood Research Society, pages 92 to 97, 2000) for cellulose nanofibers. The cellulose nanofibers dried to constant weight were precisely weighed, placed in a predetermined container, and 72 mass% sulfuric acid was added. After appropriately pressing with a glass rod so that the contents became uniform, they were autoclaved to dissolve cellulose and hemicellulose in the acid solution. After allowing to cool, the contents were filtered through glass fiber filter paper, and the acid-insoluble component was obtained as a residue. The acid-insoluble component content rate was calculated from the weight of this acid-insoluble component, and the number average of the acid-insoluble component content rates calculated for 3 samples was taken as the average acid-insoluble component content rate.

[0197] [Degree of crystallinity] X-ray diffraction measurement of the porous sheet was performed, and the degree of crystallinity was calculated from the following formula. Degree of crystallinity (%) = [I (200) -I (amorphous) / I (200) ×100 I (200) : Diffraction peak intensity by the 200 plane (2θ = 22.5°) in cellulose I-type crystal I (amorphous) : Halo peak intensity due to amorphous in cellulose I-type crystal, peak intensity on the low angle side (2θ = 18.0°) 4.5° lower than the diffraction angle of the 200 plane (X-ray diffraction measurement conditions) Apparatus MiniFlex (manufactured by Rigaku Corporation) Operation axis 2θ / θ X-ray source CuKα Measurement method Continuous type Voltage 40 kV Current 15 mA Start angle 2θ = 5° End angle 2θ = 30° Sampling width 0.020° Scan speed 2.0° / min Sample: The porous sheet was attached on the sample holder

[0198] [Number average fiber diameter] The concentrated cake was diluted with tert-butanol to 0.01% by mass, dispersed using a high-shear homogenizer (manufactured by IKA, trade name "Ultra Turrax T18") under the treatment conditions: rotation speed 15,000 rpm × 3 minutes, cast onto an osmium-evaporated silicon substrate, and air-dried, and then measured with a high-resolution scanning electron microscope (manufactured by Hitachi High-Tech Corporation, Regulus8220). The measurement was carried out by adjusting the magnification so that at least 100 cellulose nanofibers were observed, measuring the diameters (D) of 100 randomly selected cellulose nanofibers, and calculating the additive average of the 100 cellulose nanofibers as the number-average fiber diameter.

[0199] [Aspect ratio] The number-average fiber length L, number-average fiber diameter D, and number-average aspect ratio (L / D) of cellulose nanofibers in the resin composition are values measured by the following procedure using an optical microscope. A resin composition prepared by heat-kneading a resin and cellulose nanofibers was used as a measurement sample, and while heating to 220 °C on a hot stage, the cellulose nanofibers in the resin were measured with an optical microscope. Specifically, the lengths and diameters of 200 randomly selected cellulose nanofibers were measured, and the ratios were calculated. Then, the respective number-average values were taken as the number-average fiber length L and number-average fiber diameter D, and the number-average aspect ratio (L / D) was calculated.

[0200] [Specific surface area] Using a specific surface area and pore size distribution measuring device (Nova-4200e, manufactured by Quantachrome Instruments), after drying approximately 0.2 g of the porous sheet under vacuum at 120 °C for 5 hours, the nitrogen gas adsorption amount at the boiling point of liquid nitrogen was measured at 5 points in the range where the relative vapor pressure (P / P0) was 0.05 or more and 0.2 or less (multi-point method), and then the BET specific surface area (m 2 / g) was calculated by the device program.

[0201] [Thermal decomposition start temperature (T D )] The thermal analysis of the porous sheet was carried out by the following measurement method. Device: Thermo plus EVO2 manufactured by Rigaku Sample: A circular piece cut from the porous sheet was stacked and placed in an aluminum sample pan at 10 mg. Sample amount: 10 mg Measurement conditions: In a nitrogen flow of 100 ml / min, the temperature was raised from room temperature to 150 °C at a rate of 10 °C / min, held at 150 °C for 1 hour, and then directly raised to 450 °C at a rate of 10 °C / min. T D Calculation method: Obtained from a graph with temperature on the horizontal axis and weight retention rate (%) on the vertical axis. Starting from the weight of the porous sheet at 150 °C (a state where moisture was almost removed) (weight loss amount 0 wt%), the temperature was continuously raised, and a straight line passing through the temperature at 1 wt% weight loss and the temperature at 2 wt% weight loss was obtained. The temperature at the point where this straight line intersects the horizontal line (baseline) passing through the starting point of 0 wt% weight loss amount was defined as the thermal decomposition start temperature (T D ).

[0202] [Temperature at 1 wt% weight loss] The above T D The temperature at 1 wt% weight loss used in the calculation was defined as the 1 wt% weight loss temperature.

[0203] [Weight loss rate at 250 °C] Apparatus: Thermo plus EVO2 manufactured by Rigaku Sample: A circular piece cut from the porous sheet was stacked and placed in an aluminum sample pan at 10 mg. Sample amount: 10 mg Measurement conditions: In a nitrogen flow of 100 ml / min, the temperature was raised from room temperature to 150 °C at a rate of 10 °C / min, held at 150 °C for 1 hour, then raised from 150 °C to 250 °C at a rate of 10 °C / min, and directly held at 250 °C for 2 hours. Starting from the weight W0 at the time of reaching 250 °C, the weight after holding at 250 °C for 2 hours was defined as W1, and calculated from the following formula. Weight loss rate at 250 °C (%): ((W0 - W1) / W0} × 100

[0204] [Weight increase rate of cellulose nanofibers separated from the resin composition using THF] Separating cellulose nanofibers from the resin composition can be easily carried out by a method common to those skilled in the art. The separation was carried out by the following method. Using about 1.5 g of fragments of the resin composition, the resin fragments were dissolved in 70 ml of THF and separated into a soluble component (resin) and an insoluble component (cellulose nanofibers and resin adsorbed on the fiber surface). After filtering the insoluble component with filter paper, it was dried in a vacuum dryer at 80 °C for 3 hours for concentration, and the weight of the insoluble component was measured. The weight increase rate of the cellulose nanofibers was calculated from the following formula. Note that the theoretical weight below is the charged weight of the cellulose nanofibers. Weight increase rate of cellulose nanofibers (%) = (weight of insoluble component - theoretical weight of cellulose nanofibers contained in the fracture) ÷ theoretical weight of cellulose nanofibers contained in the fracture × 100

[0205] <resin composition> [Degree of whitening (void amount) at breakage] Using the test piece after testing by the tensile test method of JIS K-6251, the fracture location (2 mm in the ND direction × 3 mm in the TD direction × 4 mm in the MD direction) was observed for the MD / TD direction cross-section using X-ray CT. Device: Bruker X-CT Skyscan1272 <Conditions> Tube voltage: 40 kV, tube current: 100 μA, number of pixels: 2k (2452 × 1640 pix), pixel resolution: 2.4 μm, number of integration times: 4 times, scan: every 0.4°, analysis process: smoothing (Kuwahara filter 2 pix) Next, binarization processing of the observed image was performed to extract void locations, and the ratio (%) of the total volume of voids per unit volume was quantified.

[0206] (Binarization conditions for void locations) Binarization 0 - 35 (global range: 0 - 255), removal of objects of 4 voxels or less, and objects of 50 pixels or more in the xy cross-section are regarded as foreign substances or artifacts derived therefrom and removed (Evaluation criteria) ×: 1% or more △: 0.5% or more and less than 1% 〇: 0.02 or more and less than 0.5% ◎: less than 0.02%

[0207] [Colorability] The color of the molded dumbbell was visually evaluated. (Evaluation Criteria) ×: Caramel color △: Light caramel color 〇: Milky white ◎: White or transparent

[0208] [Tackiness] As a measuring device, the tack strength was measured using the tacking tester TAC-II manufactured by Resca Co., Ltd. The measurement mode used was Constant Load, which continues to control so that the probe is pushed in to the set pressure value and the pressure value is maintained until the set time has elapsed. Specifically, a stainless-steel probe with a flat surface of area 19.625 mm 2 was brought into contact with the surface of the measurement sample under the conditions of a probe moving speed of 120 mm / min, a pressing force (load) of 600 gf, and a pressing time of 60 seconds, and then peeled off upward under the condition of a probe moving speed (peeling speed) of 600 mm / min. The tack peak value on the surface of the resin composition by the probe tack test was measured 10 times, and the numerical value obtained by dividing the average value of the 10 measurements by the area of the probe flat surface was defined as the tack strength. The measurement was carried out at 23°C.

[0209] [Tensile stress, maximum tensile stress, strain at 400% strain] Using an ISO 37 type 3 test piece, a tensile test was carried out at a tensile speed of 5 mm / min in an environment of a temperature of 23°C and a relative humidity of 50%. Five data points of the tensile stress, maximum tensile stress, and strain at the time of breakage at 400% strain were arithmetically averaged.

[0210] ≪Materials Used≫ <Styrenic elastomer> SEBS, Tough Tech H1062 manufactured by Asahi Kasei Corporation, MFR: 4.1 g / 10 min (230°C · 2.16 kg)

[0211] <Acid-modified styrene-based elastomer> Acid-modified styrene-based elastomer 1: Maleic acid-modified SEBS, Tough Tech M1943 manufactured by Asahi Kasei Corporation, MFR: 6.5 g / 10 min (230 °C, 2.16 kg) Acid-modified styrene-based elastomer 2: Maleic acid-modified SEBS, Tough Tech M1913 manufactured by Asahi Kasei Corporation, MFR: 6.5 g / 10 min (230 °C, 2.16 kg) Acid-modified styrene-based elastomer 3: Maleic acid-modified SEBS, Tough Tech M1911 manufactured by Asahi Kasei Corporation, MFR: 4.2 g / 10 min (230 °C, 2.16 kg)

[0212] <Cellulose nanofiber (unmodified CNF)> 3 parts by mass of cotton linter pulp was immersed in 27 parts by mass of water and dispersed with a pulper. 170 parts by mass of water was added to 30 parts by mass of the cotton linter pulp slurry treated with the pulper (including 3 parts by mass of cotton linter pulp) and dispersed in water (solid content rate: 1.5% by mass). Using an SDR14 type laboratory refiner (pressure type DISK type) manufactured by Aikawa Iron Works Co., Ltd. as a disk refiner apparatus, with the clearance between the disks set to 1 mm, the aqueous dispersion was beaten for 30 minutes. Subsequently, beating was thoroughly performed under the condition of reducing the clearance to a level close to almost zero, and a beaten aqueous dispersion (solid content concentration: 1.5% by mass) was obtained. The obtained beaten aqueous dispersion was directly subjected to 10 times of micronization treatment using a high-pressure homogenizer (NSO15H manufactured by Niro Soavi (Italy)) under an operating pressure of 100 MPa to obtain a cellulose nanofiber slurry (solid content concentration: 1.5% by mass). Then, it was concentrated to a solid content rate of 10% by mass using a dehydrator to obtain a cake of cellulose nanofibers. The property values of the cellulose nanofibers are as follows. Weight average molecular weight (Mw): 380,000 Number average molecular weight (Mn): 80,000 Average content rate of alkali-soluble polysaccharides: 3.8% Average content rate of acid-insoluble components: 3.1% Crystallinity: 85% Number average fiber diameter: 75 nm Specific surface area: 34 m 2 / g Thermal decomposition start temperature (T D ): 283 °C 1 wt% weight loss temperature: 297 °C Weight loss rate at 250 °C: -2.8%

[0213] <Dispersant> Polyethylene glycol: PEG6000, manufactured by Sanyo Chemical Industries, Ltd.

[0214] <Liquid polymer> Liquid polybutadiene: RICON 184 manufactured by Kraiburg, viscosity at 25 °C: 75000 mPa·s

[0215] ≪Manufacture of resin composition≫ <Example 1> Cellulose nanofiber cake, RICON 184 and PEG6000 were blended at a ratio of 7:4:3 as solid content weight, and a planetary mixer (model number: ACM-5LVT: paddle type) manufactured by Kobayashi Seisakusho Co., Ltd. was used. While stirring at a jacket temperature of 80 °C and 307 rpm, the pressure was reduced to -90 kPa with a vacuum pump. Vacuum drying was carried out until the product temperature reached 70 °C to obtain cellulose nanofiber powder. The obtained cellulose nanofiber powder, SEBS, and acid-modified styrene-based elastomer 1 were blended at the ratios of the compositions shown in Table 1, melted at 200 °C and 200 rpm for 5 minutes using a batch-type twin-screw kneader (Explore manufactured by DSM), and a test piece (ISO 37 type 3) was produced at a mold temperature of 80 °C using a dedicated tabletop injection molding machine (manufactured by DSM).

[0216] <Examples 2 to 11, Comparative Examples 1 to 3> Resin compositions were obtained in the same manner as in Example 1 except that the formulation was changed as described in Table 1.

[0217]

Table 1

Industrial applicability

[0218] Since the resin composition according to the present disclosure can form a molded body having good physical properties, it can be suitably applied to a wide range of uses such as industrial machine parts, general machine parts, automobile, railway, vehicle, ship, and aerospace related parts, electronic and electrical parts, building and civil engineering materials, daily necessities, sports and leisure goods, housing members for wind power generation, container and packaging members, and the like.

Claims

1. A resin composition comprising a styrenic elastomer and a tack inhibitor containing cellulose nanofibers.

2. The resin composition according to claim 1, comprising 10% by mass or more of the styrenic elastomer.

3. The resin composition according to claim 1 or 2, comprising 0.1% by mass to 20% by mass of the cellulose nanofibers.

4. The resin composition according to claim 1 or 2, further comprising an acid-modified styrenic elastomer.

5. The resin composition according to claim 1 or 2, wherein the styrenic elastomer is an unmodified product.

6. The resin composition according to claim 1 or 2, comprising 0.5 parts by mass to 250 parts by mass of the styrenic elastomer with respect to 1 part by mass of the cellulose nanofibers.

7. The resin composition according to claim 1 or 2, wherein the styrenic elastomer is an aromatic vinyl compound-conjugated diene compound block copolymer or a hydrogenated product thereof.

8. The resin composition according to claim 1 or 2, wherein the MFR of the styrenic elastomer at 230 °C and 2.16 kg is 20 g / 10 min or less.

9. The resin composition according to claim 1 or 2, wherein the styrene unit ratio of the styrenic elastomer is 10 mol% to 40 mol%.

10. The resin composition according to claim 1 or 2, wherein the number average molecular weight of the styrenic elastomer is 10,000 to 500,000.

11. The resin composition according to claim 1 or 2, wherein the number average fiber diameter of the cellulose nanofibers is 2 nm to 1000 nm.

12. The resin composition according to claim 1 or 2, wherein the thermal decomposition start temperature of the cellulose nanofibers is 250 °C or higher.

13. The specific surface area of the cellulose nanofiber is 10 m 2 / g to 200 m 2 / g, and the resin composition according to claim 1 or 2.

14. The resin composition according to claim 1 or 2, further comprising a dispersant.

15. The resin composition according to claim 14, wherein the dispersant is a polymer containing a polyoxyethylene unit.

16. The resin composition according to claim 1 or 2, further comprising a liquid polymer.

17. The resin composition comprises a thermoplastic elastomer containing the styrenic elastomer and an acid-modified styrenic elastomer, and the amount of the thermoplastic elastomer is 60% by mass or more in 100% by mass of the resin composition. The resin composition according to claim 1 or 2.

18. The resin composition contains a thermoplastic elastomer containing the styrene-based elastomer, The aspect ratio, which is the ratio L / D of the length L to the width D of the cellulose nanofiber, is 2 or more and 50 or less, The resin composition according to claim 1 or 2, wherein the amount of the thermoplastic elastomer in 100% by mass of the resin composition is 60% by mass or more.

19. The resin composition contains a thermoplastic elastomer containing the styrene-based elastomer, When the cellulose nanofiber is separated from the resin composition using tetrahydrofuran (THF), the weight increase rate of the cellulose nanofiber is 150% to 600%, The resin composition according to claim 1 or 2, wherein the amount of the thermoplastic elastomer in 100% by mass of the resin composition is 60% by mass or more.

20. A method for producing the resin composition according to claim 1 or 2, The method includes a kneading step of heating and kneading a mixture containing a styrene-based elastomer and cellulose nanofibers.

21. The method according to claim 20, wherein the cellulose nanofiber used in the kneading step is a dried product having a liquid medium content of 7% by mass or less.

22. A resin molded article formed by molding the resin composition according to claim 1 or 2.

23. The resin molded article according to claim 22, which is a profile extrusion molded article.

24. A method for producing a profile extrusion molded article, The method includes a step of profile extruding the resin composition according to claim 1 or 2.

25. A molding material for 3D printing composed of the resin composition according to claim 1.

26. The molding material for 3D printing according to claim 25, which has a filament or powder form.

27. A molded article formed by molding the resin composition according to claim 1 or 2 or the molding material for 3D printing according to claim 25 with a 3D printer.

28. A method for producing a molded article, The method includes a step of molding the resin composition according to claim 1 or 2 or the molding material for 3D printing according to claim 25 with a 3D printer.

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