Shoe having rubber outsole

Abstract

To provide a shoe which realizes excellent shoe-shape holding property and walking, allows easy motion such as walking, and has excellent durability.SOLUTION: In one embodiment, a shoe include an outsole and an upper. The shoe is provided with a shank. The outsole has a deformation followability rubber member which satisfies the following formula: 0.1<(ΔM300 / 200) / (ΔM50 / 50)<0.7 (in the formula, ΔM50 and ΔM300 are an amount of stress change in 0% to 50% distortion of a stress of tensile test-distortion curve and an amount of stress change in 100% to 300%, respectively).SELECTED DRAWING: Figure 4A

Description

Technical Field

[0001] The present invention relates to shoes having a rubber outsole.

Background Art

[0002] Conventionally, rubber molded bodies have been widely used for shoe outsoles from the viewpoints of cushioning properties, wear resistance, grip properties, etc. Further, in order to further improve these properties, it has also been widely practiced to incorporate fillers into the rubber molded body. In recent years, due to the increasing awareness of environmental problems, the use of cellulose, which is a low specific gravity and renewable material, as a filler to be incorporated into the rubber molded body has been studied. Among them, cellulose nanofibers are promising as fillers for rubber molded bodies because the physical property improvement effect per amount used on the rubber molded body when combined with various rubbers to form the rubber molded body is good.

[0003] Patent Document 1 discloses a slip-resistant footwear sole having a plurality of convex portions formed on the bottom surface, wherein the footwear sole is made of a non-foamed rubber obtained by vulcanizing a rubber composition containing rubber (A) and cellulose fiber (B), the average fiber diameter of the cellulose fiber (B) is 2 to 1000 nm, the average fiber length is 0.1 to 1000 μm, the content of the cellulose fiber (B) with respect to 100 parts by mass of the rubber (A) is 0.05 to 35 parts by mass, and the hardness of the non-foamed rubber measured using a Type A durometer according to JIS K6253 is 30 to 80.

[0004] Patent Document 2 discloses a shoe sole containing a vulcanized non-foamed rubber, a filler, cellulose fiber, and a mercapto-based silane coupling agent, and having a wear amount of 470 mm3 / 1000 rotations or less as determined by the Williams abrasion test Method B of JIS K6264-2.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] When a wearer of shoes moves (such as walking or running), the sole of the shoes usually bends. However, if the part corresponding to the arch bends too easily, it becomes difficult to move. Also, in shoes having a structure where the part corresponding to the arch does not contact the ground, shape retention is required so that the heel of the shoes does not deform excessively even when the weight of the wearer is applied. From these viewpoints, for the purpose of maintaining the shape of the shoes, a member called a shank is often arranged. A shank is a member arranged at a part of the sole of the shoes that generally corresponds to the arch, and is generally a member with low flexibility (that is, high rigidity). Among the sole, the part away from the shank (for example, the forefoot part, etc.) greatly deforms due to the bending of the foot during the movement of the wearer, while the part close to the shank is suppressed from deforming significantly due to the presence of the shank. Therefore, among the sole, ease of large deformation is required for the part where large deformation is assumed, while difficulty of small deformation is required for the part where small deformation is assumed. In addition, high durability is required for the material of the sole regardless of the part.

[0007] The footwear soles described in Patent Documents 1 and 2 may have the advantage of reducing the environmental load by using cellulose fibers. However, these documents do not pay attention to the sole characteristics required due to the presence of the shank. In the prior art, shoes having excellent shoe shape retention, easy movement such as walking and running, and excellent durability have not been provided. One aspect of the present invention aims to solve the above problems and provide shoes that achieve good shoe shape retention, ease of movement such as walking and running, and good durability. [Means for Solving the Problems]

[0008] The present disclosure includes the following items. [Item 1] A shoe comprising an outsole and an upper, wherein the shoe comprises a shank, wherein the outsole has a deformation-following rubber member satisfying the following formula: 0.1 < (ΔM300 / 200) / (ΔM50 / 50) < 0.7 (wherein ΔM50 and ΔM300 are the amounts of change in stress at strains of 0% to 50% and 100% to 300% of the stress-strain curve of the tensile test, respectively.) A shoe having a deformation-following rubber member that satisfies the formula. [Item 2] The shoe according to Item 1, wherein the deformation-following rubber member satisfies the following formula: 2.0 MPa < M50 < 7.0 MPa 1.5 < M300 / M50 < 5.0 (wherein M50 and M300 are the stresses at strains of 50% and 300% in the tensile test, respectively.) The shoe according to Item 1, which satisfies the formula. [Item 3] The shoe according to Item 1 or 2, wherein the deformation-following rubber member satisfies the following formula: 3.5 MPa < M100 < 10 MPa 1.0 < M300 / M100 < 2.5 (wherein M100 and M300 are the stresses at strains of 100% and 300% in the tensile test, respectively.) The shoe according to Item 1 or 2, which satisfies the formula. [Item 4] The shoe according to any one of Items 1 to 3, wherein the deformation-following rubber member is present at least in the forefoot portion. [Item 5] The shoe according to Item 4, wherein the deformation-following rubber member is present at least in the forefoot portion and the midfoot portion. [Item 6] The shoe according to Item 5, wherein the deformation-following rubber member extends across the forefoot portion and the midfoot portion. [Item 7] The shank is present in the midfoot portion of the outsole as a part of the outsole, The shoe according to any one of Items 1 to 6, wherein the deformation-following rubber member is in contact with the shank. [Item 8] The shoe further includes a midsole, The shoe according to any one of Items 1 to 6, wherein the shank is disposed between the outsole and the midsole. [Item 9] The shoe according to any one of Items 1 to 8, wherein the deformation-following rubber member has an uneven pattern on the exposed surface of the outsole. [Item 10] The shoe according to any one of Items 1 to 9, wherein the deformation-following rubber member contains one or more selected from the group consisting of butadiene rubber, styrene-butadiene rubber, isoprene rubber, acrylonitrile-butadiene rubber, and natural rubber. [Item 11] The shoe according to any one of Items 1 to 10, wherein the deformation-following rubber member further contains cellulose nanofibers. [Item 12] The shoe according to any one of Items 1 to 11, wherein the deformation-following rubber member does not contain a hollow filler. [Item 13] A method for manufacturing a shoe according to any one of Items 1 to 12, The deformation-following rubber member contains cellulose nanofibers, The method includes a step of manufacturing a masterbatch containing cellulose nanofibers and a first rubber, a step of mixing the masterbatch and a second rubber to obtain a rubber composition, a step of curing the rubber composition to obtain the deformation-following rubber member, and a step of assembling a shoe including an outsole having the deformation-following rubber member and an upper. A method including [Advantages of the Invention]

[0009] According to one aspect of the present invention, a shoe can be provided that realizes good shoe shape retention, ease of movement such as walking and running, and good durability.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4A

Figure 4B

Figure 5A

Figure 5B

Modes for Carrying Out the Invention

[0011] 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. In the drawings, elements with the same reference numerals are intended to have the same functions.

[0012] Figs. 1 and 2 are schematic views showing a configuration example of shoes according to an aspect of the present invention. Referring to Figs. 1 and 2, an aspect of the present invention provides shoes 10, 20 including outsoles 11, 21 and uppers 12, 22. In one aspect, as shown in Fig. 1, the shoe 10 may further have a midsole 13. The shoes 10, 20 may further have an insole (not shown) in one aspect. The outsoles 11, 21 are exposed to the outside of the shoes, and at least a part, and in one aspect, all of the exposed surfaces may constitute a ground contact surface. A part of the exposed surface of the outsoles 11, 21 (for example, the part corresponding to the instep) may not be in contact with the ground. The midsole 13 is disposed between the outsole 11 and the upper 12. The insole (not shown) is exposed in the internal space (i.e., the foot insertion part) of the shoes 10, 20. The insole may be detachable.

[0013] The shoes 10, 20 have a shank S. The arrangement of the shank S is not limited. For example, as shown in Fig. 1, it may be disposed between the outsole 11 and the midsole 13, or, as shown in Fig. 2, it may exist as a part of the outsole 21. The types of shoes are not limited, and examples include leather shoes, sneakers, various work shoes, sandals, etc. The upper may have a shape that covers the entire foot, or may have a shape that does not cover, for example, the toe part and / or the heel part.

[0014] Fig. 3 is a view of the shoes shown in Figs. 1 and 2 as seen from the outsole side. Generally, the parts of the shoes are divided into a forefoot part F, a midfoot part M, and a heel part H from the toe side toward the heel side. The midfoot part M is a part including a part that generally corresponds to the instep of the wearer. Referring to Fig. 3, when the length of the long side of the rectangle circumscribing the outsole surface is defined as the outsole length L and the length of the short side is defined as the outsole width W, with respect to 100% of the outsole length L, the length of the forefoot part F may be about 45%, the length of the midfoot part M may be about 25%, and the length of the heel part H may be about 30%. The shank S is usually disposed in the midfoot part M of the shoes.

[0015] The material of the upper is not limited. For example, one or more of natural leather, artificial leather, synthetic fiber, natural fiber, etc. may be selected as desired. The upper may be combined with the outsole and / or midsole in a conventionally known manner such as sewing or adhesion.

[0016] The material of the midsole is not particularly limited. For example, foams such as ethylene-vinyl acetate copolymer, polyurethane, and polyethylene can be exemplified.

[0017] The shank only needs to have a shape and material that can suppress deformation of the sole in the front-back direction, left-right direction, and / or diagonal direction during wearing. When the shank is disposed between the outsole and the midsole, it can be, for example, a plate-like object. When the shank is disposed as a part of the outsole, it may have various shapes as desired and may be joined to other parts of the outsole by adhesion or the like. The shank of the outsole may have, for example, an uneven pattern on its surface. The material of the shank may be appropriately selected as desired, and examples thereof include polyamide, fiber-reinforced plastic, polyester, polyolefin, polyvinyl chloride, acrylonitrile-butadiene-styrene (ABS), ethylene-vinyl acetate copolymer (EVA), and polystyrene.

[0018] The outsole of the present embodiment has a deformation-following rubber member with controlled modulus. FIGS. 4A and 4B are diagrams showing an example of the outsole surface (exposed surface) of the shoe shown in FIG. 1, and FIGS. 5A and 5B are diagrams showing an example of the outsole surface (exposed surface) of the shoe shown in FIG. 2. That is, FIGS. 4A and 4B illustrate the case where the shank is disposed outside the outsole, and FIGS. 5A and 5B illustrate the case where the shank exists as a part of the outsole. Referring to FIG. 4A, the outsole 11a may be a single member composed of the deformation-following rubber member 111. Alternatively, referring to FIG. 4B, the outsole 11b may be a combination of the deformation-following rubber member 111 and an additional member 112. Referring to FIGS. 5A and 5B, when the shank S exists in the outsoles 21a, 21b, as shown in FIG. 5A, the outsole 21a may be composed of the deformation-following rubber member 211 and the shank S, and as shown in FIG. 5B, the outsole 21b may be a combination of the deformation-following rubber member 211, the shank S, and an additional member 212. The number, position, and shape of the additional member are not limited and may be arbitrarily designed as desired. The material of the additional member may include one or more of the components exemplified as components of the deformation-following rubber member.

[0019] The shoe of the present embodiment includes a shank. Therefore, among the outsole, the deformation is suppressed by the presence of the shank in the portion near the shank, while at least a part of the portion away from the shank is greatly deformed by the movements such as walking and running of the wearer. Among the outsole, the portion near the shank is, in one aspect, the portion overlapping the shank when the shank exists between the outsole and the midsole, and in one aspect, the portion adjacent to the shank when the shank is a part of the outsole. Among the outsole, the portion away from the shank and greatly deformed during operation is, in one aspect, the forefoot portion. Therefore, among the outsole, in the midfoot portion, the difficulty of deformation against small deformation is required from the viewpoint of the shape retention of the shoe, while in the forefoot portion, the ease of deformation against large deformation is required from the viewpoint of the ease of operation.

[0020] ≪Deformation-Following Rubber Member≫ The modulus of the deformation-following rubber member of this embodiment is controlled so as to have both the difficulty of deformation during small deformation and the ease of deformation during large deformation. As a result, the deformation-following rubber member can exhibit the desired deformation behavior at the site, regardless of whether it is arranged at a site near the shank, a site far from the shank, or any other site. That is, the deformation-following rubber member of this embodiment can be applied regardless of the site in outsole manufacturing, so the number of members constituting the shoe can be reduced. The fact that the number of members is small is advantageous in terms of simplifying the manufacturing process, reducing peeling by increasing the adhesive area between members, and simplifying the process during repairs such as sole replacement.

[0021] The deformation-following rubber member preferably exists at least in the forefoot portion, preferably exists at least in the forefoot portion and the midfoot portion, and preferably extends across the forefoot portion and the midfoot portion. When the deformation-following rubber member is arranged in the forefoot portion, it contributes to the ease of movements such as walking and running due to the contribution of the ease of deformation during large deformation. When the deformation-following rubber member is arranged in the midfoot portion, it contributes to the shoe shape retention property due to the difficulty of deformation during small deformation. When the deformation-following rubber member extends across the forefoot portion and the midfoot portion (for example, as shown in FIGS. 4A, 4B, 5A, and 5B), the compatibility between the ease of movement and the shoe shape retention property can be achieved with a single deformation-following rubber member. The use of such a single member is advantageous in terms of simplifying the manufacturing process by reducing the number of members.

[0022] Referring to FIGS. 5A and 5B, in one aspect, the shank S exists in the midfoot portion M of the outsole, and the deformation-following rubber member 211 is in contact with the shank S. In a typical aspect, the deformation-following rubber member and the shank are joined by adhesion or the like. The deformation-following rubber member is excellent in the similarity of deformation behavior with the shank S due to the contribution of the difficulty of small deformation. Such a deformation-following rubber member is advantageous in that it is difficult to peel from the shank at the joint with the shank.

[0023] Referring to FIGS. 4A and 5B, even in the mode where the shank is disposed outside the outsole, when the deformation-following rubber member 111 exists in the midfoot portion M, the outsole overlapping the shank can exhibit a deformation behavior similar to that of the shank. As a result, the advantage of being able to more efficiently suppress the torsional movement of the foot during running can be obtained.

[0024] In one aspect, the deformation-following rubber member may have a concavo-convex pattern on the exposed surface of the outsole. In one aspect, the concavo-convex pattern may be provided on a part of the exposed surface of the outsole (for example, at least a part of the ground contact surface) or the entire exposed surface of the outsole for the purpose of improving grip performance or the like. The shape of the concavo-convex pattern is not limited, and a plurality of grooves such as V-shaped or corrugated may be arranged.

[0025] In one aspect, the deformation-following rubber member satisfies the following formula: 0.1 < (ΔM300 / 200) / (ΔM50 / 50) < 0.7 (wherein ΔM50 and ΔM300 are the change amounts of stress at strains of 0% to 50% and 100% to 300% in the stress-strain curve of the tensile test, respectively.) is satisfied.

[0026] ΔM50 is an index of the stress required for deformation during small deformation (i.e., the difficulty of deformation). On the other hand, ΔM300 is an index of the stress required for deformation during large deformation (i.e., the difficulty of deformation). Usually, in rubber materials, as the strain increases, the stress tends to increase. The fact that the ratio (ΔM300 / 200) / (ΔM50 / 50) is within a predetermined range means that it is difficult to deform during small deformation but easy to deform during large deformation. A rubber member having such characteristics is extremely advantageous in that it can be used regardless of the site in the outsole. That is, when such a rubber member is disposed near the shank, it contributes to the shoe shape retention, while when disposed, for example, at the forefoot, it contributes to the ease of movement. From the above viewpoints, the ratio (ΔM300 / 200) / (ΔM50 / 50) is, in one aspect, greater than 0.1, or greater than or equal to 0.13, or greater than or equal to 0.14, or greater than or equal to 0.15, or greater than or equal to 0.18, or greater than or equal to 0.19, or greater than or equal to 0.20, and in one aspect, less than 0.7, or less than or equal to 0.6, or less than or equal to 0.4, or less than or equal to 0.35.

[0027] In one aspect, the deformation-following rubber member satisfies the following formula: 2.0 MPa < M50 < 7.0 MPa 1.5 < M300 / M50 < 5.0 (wherein M50 and M300 are the stresses at 50% and 300% strain, respectively, in the tensile test.) and satisfies.

[0028] From the viewpoint of shoe shape retention, M50 is preferably greater than 2.0 MPa, or greater than or equal to 2.5 MPa, or greater than or equal to 3.0 MPa, and from the viewpoint of obtaining a good wearing feeling by bending to some extent even during small deformation, it is preferably less than 7.0 MPa, or less than or equal to 6.5 MPa, or less than or equal to 6.0 MPa.

[0029] From the viewpoint of shoe shape retention, M300 is preferably 4.0 MPa or more, or 4.5 MPa or more, or 5.0 MPa or more, and from the viewpoint of ease of movement, it is preferably 18 MPa or less, or 15 MPa or less, or 13 MPa or less, or 12.5 MPa or less.

[0030] The M300 / M50 ratio is preferably greater than 1.5, or 2.0 or more, or 2.5 or more, and preferably less than 5.0, or 4.0 or less, or 3.5 or less, from the viewpoint of achieving both difficulty in deformation during small deformation and ease of deformation during large deformation.

[0031] In one aspect, the deformation-following rubber member satisfies the following formula: 3.5 MPa < M100 < 10 MPa 1.0 < M300 / M100 < 2.5 (wherein M100 and M300 are the stresses at 100% and 300% strain, respectively, in the tensile test.) and satisfies it.

[0032] From the viewpoint of shoe shape retention, M100 is preferably greater than 3.5 MPa, or 4.0 MPa or more, or 4.5 MPa or more, and from the viewpoint of obtaining a good wearing feeling by being bent to some extent even during small deformation, it is preferably less than 10 MPa, or 9.0 MPa or less, or 8.5 MPa or less, or 8.0 MPa or less.

[0033] From the viewpoint of achieving both difficulty in deformation during small deformation and ease of deformation during large deformation, the M300 / M100 ratio is preferably greater than 1.0, or 1.2 or more, or 1.3 or more, or 1.4 or more, or 1.5 or more, and preferably less than 2.5, or 2.2 or less, or 2.1 or less.

[0034] In one aspect, the deformation-following rubber member satisfies the following formula: 0.1 < (ΔM300 / 200) / (ΔM100 / 100) < 0.7 (In the formula, ΔM100 and ΔM300 are the change in stress from 0% to 100% strain and the change in stress from 100% to 300% strain in the stress-strain curve of the tensile test, respectively.) is satisfied. When the above ratio is within the above range, it is advantageous in that it is difficult to deform during small deformation and easy to deform during large deformation. The ratio (ΔM300 / 200) / (ΔM100 / 100) is preferably more than 0.1, or 0.13 or more, or 0.14 or more, or 0.15 or more, or 0.18 or more, or 0.19 or more, or 0.20 or more, and in one aspect, less than 0.7, or 0.6 or less, or 0.5 or less, or 0.4 or less, or 0.35 or less.

[0035] The modulus is a value measured by a method conforming to JIS K 6251.

[0036] From the viewpoint of the durability of the shoe, the Shore A hardness of the deformation-tracking rubber member is preferably 40 or more, or 50 or more, or 55 or more, or 60 or more, and from the viewpoint of the wearing feeling, preferably 85 or less, or 80 or less, or 75 or less, or 70 or less. The hardness is a value measured by a method conforming to JIS K 6253-3.

[0037] From the viewpoint of the durability of the shoe, the tensile strength of the deformation-tracking rubber member is preferably 4.0 MPa or more, or 5.0 MPa or more, or 5.5 MPa or more, and from the viewpoint of the ease of manufacturing the deformation-tracking rubber member, preferably 25 MPa or less, or 20 MPa or less, or 18 MPa or less, or 17 MPa or less, or 16 MPa or less, or 15 MPa or less. The tensile strength is a value measured by a method conforming to JIS K 6251-1.

[0038] From the viewpoint of the durability of the shoe, the tear strength of the deformation-tracking rubber member is preferably 40 N / mm or more, or 45 N / mm or more, or 50 N / mm or more, and from the viewpoint of the ease of manufacturing the deformation-tracking rubber member, preferably 90 N / mm or less, or 80 N / mm or less, or 75 N / mm or less. The tear strength is a value measured by a method conforming to JIS K 6252.

[0039] From the viewpoint of wear resistance, the wear volume of the deformation-following rubber member is 0.4 cc or less, or 0.35 cc or less, or 0.3 cc or less, and from the viewpoint of ease of manufacturing of the deformation-following rubber member, it is preferably 0.1 cc or more, or 0.12 cc or more, or 0.15 cc or more. The wear volume is a value measured by the DIN wear test method according to JIS K 6264-2.

[0040] In one aspect, the storage elastic modulus of the deformation-following rubber member may be 2.5 MPa or more, or 2.8 MPa or more, or 3.0 MPa or more, or 3.5 MPa or more, and in one aspect, it may be 8.0 MPa or less, or 7.5 MPa or less, or 7.0 MPa or less.

[0041] In one aspect, from the viewpoint of taking advantage of the repulsive force from the ground during movement, the loss tangent of the deformation-following rubber member may be 0.15 or less, or 0.13 or less, or 0.10 or less, and in one aspect, from the viewpoint of grip performance, it may be 0.05 or more, or 0.06 or more, or 0.07 or more. The above storage elastic modulus and loss tangent are values measured at 50 °C, 10 Hz, and 3% strain in a torsional manner using a rheometer.

[0042] <Rubber (matrix rubber)> The deformation-following rubber member contains rubber and optionally other components. Hereinafter, the rubber that can constitute the matrix of the deformation-following rubber member (also referred to as matrix rubber in the present disclosure) will be described. In one aspect, the matrix rubber is a cured product (a crosslinked product in one aspect). Examples of the matrix rubber include natural rubber, conjugated diene polymers, non-conjugated diene polymers, and thermoplastic elastomers. The matrix rubber preferably contains one or more selected from the group consisting of butadiene rubber, styrene-butadiene rubber, isoprene rubber, acrylonitrile-butadiene rubber, and natural rubber. Butadiene rubber can mainly contribute to abrasion resistance, styrene-butadiene rubber can mainly contribute to grip performance, isoprene rubber can mainly contribute to tensile strength and tear strength, acrylonitrile-butadiene rubber can mainly contribute to oil grip performance, and natural rubber can mainly contribute to tensile strength and tear strength.

[0043] For example, the rubber composition for forming the deformation-following rubber member may be obtained by mixing a masterbatch containing a first rubber and a second rubber. The first rubber and the second rubber can constitute the matrix rubber. The first rubber and the second rubber may be of the same type (in particular, having the same constituent monomer species and molecular weight), or may be of different types (in particular, having different constituent monomer species and / or molecular weight). Hereinafter, examples of the matrix rubber will be described.

[0044] [Natural Rubber] The natural rubber is not particularly limited. For example, from the viewpoint that a large amount of high molecular weight components is excellent in breaking strength: RSS (Ribbed Smoked Sheet) Nos. 3 to 5 of the smoke-dried type; as TSR (Technically Specified Rubber) of mechanical drying, SIR (Standard Indonesian Rubber) (produced in Indonesia), STR (Standard Thai Rubber) (produced in Thailand), SMR (Standard Malaysian Rubber) (produced in Malaysia), etc.; and epoxidized natural rubber, etc. can be mentioned.

[0045] [Conjugated Diene Polymer] The conjugated diene polymer may be a homopolymer, or may be 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.

[0046] 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.

[0047] 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 thereof include styrene, 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 and impact resistance of the rubber member, styrene is preferred.

[0048] Examples of the random copolymer include butadiene-isoprene random copolymer, butadiene-styrene random copolymer, isoprene-styrene random copolymer, and 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 such as 1,4-bond and 1,2-bond, may be uniform or different among molecules.

[0049] The block copolymer may be a copolymer composed of two or more blocks. For example, a block A of an aromatic vinyl monomer and a 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 may form a block copolymer having 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 distinguishable. 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, in block B, there may be a plurality of portions where the aromatic vinyl monomer is uniformly distributed and / or portions where it is distributed in a tapered shape. Further, in block B, there may be a plurality of segments having different aromatic vinyl monomer contents. 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.

[0050] 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, total amount of 1,2-vinyl content or 1,2-vinyl content and 3,4-vinyl content, aromatic vinyl compound component content, hydrogenation rate, etc. are different from each other.

[0051] The amount of vinyl bonds in the conjugated diene bond units in the conjugated diene polymer (for example, 1,2- or 3,4-bonds of butadiene) is preferably 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 (for example, the amount of 1,2-bonds of butadiene) 13 can be determined by the C-NMR method (quantitative mode). That is, 13 By integrating the peak areas appearing below in C-NMR, a value proportional to the amount of carbon of 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

[0052] In a copolymer of a conjugated diene monomer and an aromatic vinyl monomer, the amount of the aromatic vinyl monomer bonded to the conjugated diene monomer (also referred to as the aromatic vinyl bond amount in the present disclosure) may preferably be 5.0% by mass or more and 70% by mass or less, or 10% by mass or more and 50% by mass or less, based on the total mass of the conjugated diene polymer. 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.

[0053] The conjugated diene polymer 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 butadiene homopolymer, an isoprene homopolymer, a styrene-butadiene copolymer, or an acrylonitrile-butadiene copolymer.

[0054] [Non-conjugated diene polymer] The non-conjugated diene polymer may be a homopolymer, or a copolymer of two or more non-conjugated diene monomers or a copolymer of a non-conjugated diene monomer and another monomer. The copolymer may be random or block. Examples of the non-conjugated diene polymer include olefin polymers such as ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-butene-diene rubber, and ethylene-α-olefin copolymer, butyl rubber, brominated butyl rubber, acrylic rubber, fluorine rubber, silicone rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, α,β-unsaturated nitrile-acrylic acid ester-conjugated diene copolymer rubber, urethane rubber, polysulfide rubber, etc.

[0055] In the ethylene-α-olefin copolymer, examples of the monomer copolymerizable with the ethylene unit 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, eicosene-1, isobutylene; aromatic vinyl monomers such as styrene and substituted styrene; ester-based 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; dienes such as butadiene, cyclopentadiene, 1,4-hexadiene, isoprene, and the like.

[0056] Preferably, it is a copolymer of ethylene and one or more α-olefins having 3 to 20 carbon atoms, more preferably a copolymer of ethylene and one or more α-olefins having 3 to 16 carbon atoms, and most preferably a copolymer of ethylene and one or more α-olefins having 3 to 12 carbon atoms. Further, from the viewpoint of expressing impact resistance, the number average molecular weight of the ethylene-α-olefin copolymer is preferably 10,000 or more, more preferably 10,000 to 100,000, still more preferably 10,000 to 80,000, and even more preferably 20,000 to 60,000. Also, from the viewpoint of achieving both fluidity and impact resistance, the molecular weight distribution (weight average molecular weight / number average molecular weight: Mw / Mn) is preferably 3 or less, and more preferably 1.8 to 2.7. In the present disclosure, the molecular weight and molecular weight distribution of various rubbers (including the additive rubbers described later) are values obtained by measuring a chromatogram using gel permeation chromatography in which three columns filled with a polystyrene-based gel are connected and calculating with a calibration curve using standard polystyrene. Tetrahydrofuran is used as the solvent.

[0057] Also, from the viewpoint of handleability during processing, the preferable ethylene unit content in the ethylene-α-olefin copolymer is 30 to 95% by mass based on the total amount of the ethylene-α-olefin copolymer.

[0058] These preferable ethylene-α-olefin copolymers can be produced, for example, by the production methods described in Japanese Patent Publication No. 4-12283, Japanese Unexamined Patent Application Publication Nos. 60-35006, 60-35007, 60-35008, 5-155930, 3-163088, and U.S. Patent No. 5272236.

[0059] [Modified Rubber] The rubber may be a modified rubber. For example, in the conjugated diene polymer or non-conjugated diene polymer exemplified above, a modifying group such as an epoxy group, acid anhydride group, carboxy group, aldehyde group, hydroxyl group, alkoxy group, amino group, amide group, imide group, nitro group, isocyanate group, or mercapto group may be introduced. Examples of the modified rubber include epoxy-modified natural rubber, epoxy-modified butadiene rubber, epoxy-modified styrene-butadiene rubber, carboxy-modified natural rubber, carboxy-modified butadiene rubber, carboxy-modified styrene-butadiene rubber, acid anhydride-modified natural rubber, acid anhydride-modified butadiene rubber, and acid anhydride-modified styrene-butadiene rubber.

[0060] The amount of the modifying group relative to 100 mol% of the whole monomer unit is preferably 0.1 mol% or more, or 0.2 mol% or more, or 0.3 mol% or more, and preferably 5 mol% or less, or 3 mol% or less, from the viewpoint of the affinity with the cellulose nanofiber. The amount of the modifying group can be confirmed by a method of calculating the molar ratio of the modifying group by combining infrared absorption spectroscopy, solid NMR (nuclear magnetic resonance), solution NMR, or elemental analysis of elements not contained in the unmodified rubber with a specified monomer composition in advance.

[0061] [Thermoplastic elastomer] In one aspect, the rubber can include or be a thermoplastic elastomer. In the present disclosure, the elastomer is, in one aspect, a substance (specifically, a natural or synthetic polymer substance) that is an elastomer at room temperature (23 °C). Also, being an elastomer 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. The thermoplastic elastomer may be a conjugated diene polymer or a non-conjugated diene polymer, and may be a cured product (a crosslinked product in one aspect). The preferred monomer composition of the thermoplastic elastomer may be the same as described above in the sections of (conjugated diene polymer) and (non-conjugated diene polymer).

[0062] The number average molecular weight (Mn) of the thermoplastic elastomer is preferably 10,000 to 500,000, or 40,000 to 250,000, from the viewpoint of achieving both impact strength and fluidity.

[0063] The thermoplastic elastomer may have a core-shell structure. Examples of the elastomer having a core-shell structure include core-shell type elastomers having a particulate rubber as the core and a glassy graft layer formed outside the core as the shell. As the core, butadiene rubber, acrylic rubber, silicone-acrylic composite rubber, etc. are suitable. Also, as the shell, glassy polymers such as styrene resin, acrylonitrile-styrene copolymer, acrylic resin, etc. are suitable.

[0064] From the perspective of grip characteristics, the thermoplastic elastomer is preferably at least one selected from the group consisting of styrene-butadiene block copolymer, styrene-ethylene-butadiene block copolymer, styrene-ethylene-butylene block copolymer, styrene-butadiene-butylene block copolymer, styrene-isoprene block copolymer, styrene-ethylene-propylene block copolymer, styrene-isobutylene block copolymer, hydrogenated 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 selected from the group consisting of styrene-butadiene block copolymer, hydrogenated product of styrene-butadiene block copolymer, and polystyrene.

[0065] In one aspect, at least a part of the thermoplastic elastomer may have an acidic functional group. In the present disclosure, that the thermoplastic elastomer has an acidic functional group means that an acidic functional group is added through a chemical bond in the molecular skeleton of the 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. Specific examples include a hydroxyl group, a carboxyl group, a carboxylate group, a sulfo group, an acid anhydride group, and the like.

[0066] From the perspective of adhesion to the filler, the addition amount of the acidic functional group in the elastomer is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, still more preferably 0.2% by mass or more, preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 2% by mass or less, and still more preferably less than 1.5% by mass based on 100% by mass of the elastomer. The number of acidic functional groups is a value obtained by measuring the sample based on a calibration curve prepared using the characteristic absorption band of the acid, by measuring a calibration curve sample with an acidic substance mixed in advance using an infrared absorption spectrometer.

[0067] Examples of the elastomer having an acidic functional group include an elastomer having a core-shell structure having a layer formed using acrylic acid or the like as a copolymerization component as a shell, an ethylene-α-olefin copolymer containing acrylic acid or the like as a monomer, a polyolefin, an aromatic compound-conjugated diene copolymer, or a modified product obtained by grafting an α,β-unsaturated dicarboxylic acid or a derivative thereof to an aromatic compound-conjugated diene copolymer hydrogenated product in the presence or absence of a peroxide.

[0068] In a preferred embodiment, the elastomer is an elastomer modified with an acid anhydride.

[0069] Among these, modified products obtained by grafting an α,β-unsaturated dicarboxylic acid or a derivative thereof to a polyolefin, an aromatic compound-conjugated diene copolymer, or an aromatic compound-conjugated diene copolymer hydrogenated product in the presence or absence of a peroxide are more preferred. Among them, modified products obtained by grafting an α,β-unsaturated dicarboxylic acid and a derivative thereof to a copolymer of ethylene-α-olefin or a hydrogenated product of an aromatic compound-conjugated diene block copolymer in the presence or absence of a peroxide are particularly preferred.

[0070] Specific examples of the α,β-unsaturated dicarboxylic acid and a derivative thereof include maleic acid, fumaric acid, maleic anhydride, and fumaric anhydride. Among these, maleic anhydride is particularly preferred.

[0071] In one aspect, the elastomer may be a mixture of an elastomer having an acidic functional group and an elastomer having no acidic functional group. When the total of both is 100% by mass, the mixing ratio of the elastomer having an acidic functional group and the elastomer having no acidic functional group is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, and most preferably 40% by mass or more from the viewpoint of maintaining good high toughness and physical property stability of the rubber cured product. The upper limit is not particularly limited, and substantially all the elastomers may be elastomers having an acidic functional group, but 80% by mass or less is desirable from the viewpoint of not causing problems in fluidity.

[0072] <Rubber (Additive Rubber)> In one aspect, the rubber composition used for forming the deformation-following rubber member may further contain, in addition to the rubber described in the above <Rubber (Matrix Rubber)> section, rubber as an additive (also referred to as additive rubber in the present disclosure). In one aspect, the additive rubber is a liquid rubber. 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. Further, having fluidity means that, in one aspect, after dissolving the liquid rubber in cyclohexane and putting it 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 rubber 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 the substance in the height direction of 0.1 mm or more can be confirmed. The liquid rubber may have a monomer composition of a general rubber, and is preferably relatively low molecular weight from the viewpoints of ease of handling and good dispersibility of cellulose nanofibers. The liquid rubber exhibits a liquid shape by having a number average molecular weight (Mn) of 150,000 or less in one aspect.

[0073] When curing a rubber composition to form a rubber cured product constituting a deformation-following rubber member, from the viewpoint of improving the mechanical properties of the rubber cured product, it is desirable that the liquid rubber be vulcanized during curing. Alternatively, the liquid rubber may be cured by heat or the like.

[0074] The additive rubber may be a third rubber mixed with the cellulose nanofiber before mixing the cellulose nanofiber and the matrix rubber, or a fourth rubber added during the mixing of the cellulose nanofiber and the matrix rubber, or a combination of the third rubber and the fourth rubber.

[0075] From the viewpoint of obtaining good mechanical properties of the rubber cured product, the number average molecular weight of the third rubber is preferably 1,000 or more, or 1,500 or more, or 2,000 or more. From the viewpoints of fluidity and obtaining a rubber cured product having good rubber elasticity without becoming too hard, it is preferably 150,000 or less, or 145,000 or less, or 140,000 or less.

[0076] From the viewpoint of obtaining good mechanical properties of the rubber cured product, the number average molecular weight of the fourth rubber is preferably 4,500 or more, or 5,000 or more, or 5,500 or more. From the viewpoints of fluidity and obtaining a rubber cured product having good rubber elasticity without becoming too hard, it is preferably 100,000 or less, or 90,000 or less, or 80,000 or less.

[0077] From the viewpoints of fluidity and obtaining a rubber cured product having good rubber elasticity without becoming too hard, the viscosity η1 of the third rubber at 38°C is preferably 100,000 mPa·s or less, or 95,000 mPa·s or less, or 90,000 mPa·s or less. From the viewpoint of obtaining good mechanical properties of the rubber cured product, it is preferably 5,000 mPa·s or more, or 8,000 mPa·s or more, or 10,000 mPa·s or more.

[0078] The viscosity η2 of the fourth rubber at 38°C is preferably 800,000 mPa·s or less, or 700,000 mPa·s or less, or 600,000 mPa·s or less from the viewpoint of fluidity and obtaining a rubber cured product having good rubber elasticity without becoming too hard, and preferably 100,000 mPa·s or more, or 120,000 mPa·s or more, or 140,000 mPa·s or more from the viewpoint of obtaining good mechanical properties of the rubber cured product.

[0079] In the present disclosure, the viscosity is a value measured using a B-type viscometer.

[0080] At 38°C, the ratio η2 / η1 of the viscosity η2 of the fourth rubber to the viscosity η1 of the third rubber is preferably 1.2 or more, or 1.3 or more, or 1.4 or more in terms of the third rubber being likely to penetrate between the fourth rubbers or between the fourth rubber and the cellulose nanofiber, and preferably 160 or less, or 140 or less, or 120 or less from the viewpoint of obtaining good affinity between the third rubber and the fourth rubber.

[0081] The liquid rubber may be a conjugated diene polymer or a non-conjugated diene polymer or a hydrogenated product thereof. The above polymer or its hydrogenated product may be an oligomer.

[0082] [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 random or block.

[0083] 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.

[0084] In one aspect, the conjugated diene polymer is a copolymer of the above conjugated diene monomer and aromatic vinyl monomer. The aromatic vinyl monomer is not particularly limited as long as it is copolymerizable with the conjugated diene monomer. Examples thereof 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. Styrene is preferable from the viewpoints of the moldability of the rubber composition and the impact resistance of the molded article.

[0085] 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 between molecules.

[0086] The block copolymer may be a copolymer composed of two or more blocks. For example, 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 may form block copolymers with structures such as A-B, A-B-A, A-B-A-B, etc. Note that the boundaries of each block do not necessarily have to be clearly distinguishable. 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, block B may have a plurality of portions where the aromatic vinyl monomer is uniformly distributed and / or portions where it is distributed in a tapered shape. Furthermore, block B may have a plurality of segments with different aromatic vinyl monomer contents. 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.

[0087] The block copolymer may also be a mixture of two or more types in which at least one of the bonding form, molecular weight, aromatic vinyl compound species, conjugated diene compound species, total amount of 1,2-vinyl content or 1,2-vinyl content and 3,4-vinyl content, aromatic vinyl compound component content, hydrogenation rate, etc. is different from each other.

[0088] The amount of vinyl bonds in the conjugated diene bond units in the conjugated diene polymer (for example, 1,2- or 3,4-bonds of butadiene) is preferably 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 (for example, the amount of 1,2-bonds of butadiene) 13 can be determined by the C-NMR method (quantitative mode). That is, 13 By integrating the peak areas that appear below in C-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

[0089] In a copolymer of a conjugated diene monomer and an aromatic vinyl monomer, the amount of the aromatic vinyl monomer bonded to the conjugated diene monomer (also referred to as the aromatic vinyl bond amount in the present disclosure) is preferably 5.0% by mass or more and 70% by mass or less, or 10% by mass or more and 50% by mass or less, based on the total mass of the conjugated diene polymer. 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.

[0090] The conjugated diene polymer 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. 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 butadiene homopolymer, an isoprene homopolymer, a styrene-butadiene copolymer, or an acrylonitrile-butadiene copolymer.

[0091] [Non-conjugated diene polymer] The non-conjugated diene polymer may be a homopolymer, or a copolymer of two or more non-conjugated diene monomers or a copolymer of a non-conjugated diene monomer and another monomer. The copolymer may be random or block. Examples of the non-conjugated diene polymer include Olefin-based polymers such as ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-butene-diene rubber, and ethylene-α-olefin copolymer, Examples include butyl rubber, brominated butyl rubber, acrylic rubber, fluororubber, silicone rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, α,β-unsaturated nitrile-acrylic acid ester-conjugated diene copolymer rubber, urethane rubber, polysulfide rubber, and the like.

[0092] 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, eicosene-1, isobutylene; aromatic vinyl monomers such as styrene and substituted styrene; ester-based 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; dienes such as butadiene, cyclopentadiene, 1,4-hexadiene, isoprene, and the like.

[0093] Preferably, it is a copolymer of ethylene and one or more α-olefins having 3 to 20 carbon atoms, more preferably a copolymer of ethylene and one or more α-olefins having 3 to 16 carbon atoms, and most preferably a copolymer of ethylene and one or more α-olefins having 3 to 12 carbon atoms. Further, from the viewpoint of expressing impact resistance, the number average molecular weight of the ethylene-α-olefin copolymer is preferably 10,000 or more, more preferably 10,000 to 100,000, still more preferably 10,000 to 80,000, and even more preferably 20,000 to 60,000. Also, from the viewpoint of achieving both fluidity and impact resistance, the molecular weight distribution (weight average molecular weight / number average molecular weight: Mw / Mn) is preferably 3 or less, and more preferably 1.8 to 2.7.

[0094] Further, from the viewpoint of handleability during processing, the preferable ethylene unit content in the ethylene-α-olefin copolymer is 30 to 95% by mass based on the total amount of the ethylene-α-olefin copolymer.

[0095] These preferable ethylene-α-olefin copolymers can be produced by the production methods described in, for example, Japanese Patent Publication No. 4-12283, Japanese Unexamined Patent Application Publication No. 60-35006, Japanese Unexamined Patent Application Publication No. 60-35007, Japanese Unexamined Patent Application Publication No. 60-35008, Japanese Unexamined Patent Application Publication No. 5-155930, Japanese Unexamined Patent Application Publication No. 3-163088, U.S. Patent No. 5272236, and the like.

[0096] The liquid rubber is preferably at least one selected from the group consisting of styrene-butadiene rubber, natural rubber, butadiene rubber, farnesene rubber, and isoprene rubber.

[0097] In one aspect, the third rubber may be an unmodified liquid rubber. Preferable examples of the unmodified liquid rubber are the polymers exemplified above. In one aspect, the fourth rubber may be a modified liquid rubber. The modified liquid rubber may have a structure in which at least one kind of modifying group is introduced into each of the polymers exemplified above. The modifying group may be one kind or two or more kinds selected from epoxy group, acid anhydride group, carboxy group, aldehyde group, hydroxyl group, alkoxy group, amino group, amide group, imide group, nitro group, isocyanato group, thio group, mercapto group, and the like. The modifying group is preferably at least one selected from the group consisting of maleic anhydride group and succinic anhydride group, or is maleic anhydride group. Examples of the modified liquid rubber include epoxy-modified natural rubber, epoxy-modified butadiene rubber, epoxy-modified styrene-butadiene rubber, epoxy-modified isoprene rubber, carboxy-modified natural rubber, carboxy-modified butadiene rubber, carboxy-modified styrene-butadiene rubber, carboxy-modified isoprene rubber, acid anhydride-modified natural rubber, acid anhydride-modified butadiene rubber, acid anhydride-modified styrene-butadiene rubber, acid anhydride-modified isoprene rubber, and the like.

[0098] The modified liquid rubber may have reactive groups (e.g., one or more selected from the group consisting of a hydroxyl group, a carboxy group, an isocyanato group, a thio group, an amino group, and a halo group) at both ends, and thus may be bifunctional. These reactive groups contribute to the crosslinking and / or chain extension of the modified liquid rubber.

[0099] In the modified liquid rubber, the amount of the modifying group relative to 100 mol% of all monomer units is preferably 0.1 mol% or more, or 0.2 mol% or more, or 0.3 mol% or more in terms of good dispersibility and orientation of the cellulose nanofibers due to good affinity between the cellulose nanofibers and the modified liquid rubber. On the other hand, when the amount of the modifying group is excessive, the modified liquid rubbers or the modified liquid rubber and the cellulose nanofibers tend to form a dense structure, and the dispersibility and orientation of the cellulose nanofibers tend to decrease. In order to impart desired mechanical properties and surface smoothness to the rubber cured product, it is desirable to suppress the formation of such a dense structure. From the above viewpoints, the amount of the modifying group relative to 100 mol% of all monomer units is preferably 5 mol% or less, or 3 mol% or less. The amount of the modifying group can be confirmed by a method of calculating the molar ratio of the modifying group by combining infrared absorption spectroscopy, solid NMR (nuclear magnetic resonance), solution NMR, or elemental analysis of a previously specified monomer composition and an element not contained in the unmodified rubber.

[0100] The modifying group content of the modified liquid rubber is preferably 0.5 mass% or more, or 0.8 mass% or more, or 1.0 mass% or more in terms of good dispersibility and orientation of the cellulose nanofibers due to good affinity between the cellulose nanofibers and the modified liquid rubber, and is preferably 20 mass% or less, or 15 mass% or less, or 10 mass% or less from the viewpoint of suppressing the formation of the above dense structure. This modifying group content can be confirmed by NMR in one aspect.

[0101] The means for producing the modified liquid rubber is not particularly limited, and for example, the method described in JP-A-2016-172859 can be used.

[0102] In one aspect, the modifying groups of the modified liquid rubber can form covalent bonds with cellulose nanofibers and / or other rubbers during the production of the rubber composition or the rubber cured product, particularly during heat mixing. The covalent bonds can be advantageous in further enhancing the reinforcing effect by the cellulose nanofibers. In one aspect, covalent bonds are formed between the modified liquid rubber and the cellulose nanofibers during the production of the rubber composition, and covalent bonds can be formed directly between the modified liquid rubber and the matrix rubber or through other components (a vulcanizing agent in one aspect) during the production of the rubber cured product (i.e., during curing).

[0103] From the perspective of improving the mechanical properties of the rubber cured product, the additive rubber may be covalently bonded to the matrix rubber through a vulcanizing agent during the curing of the rubber composition.

[0104] In one aspect, the presence of covalent bonds can be confirmed by the following method. In the rubber composition, for the residue obtained by removing the rubber with a solvent (e.g., hexane or cyclohexane), it is analyzed by nuclear magnetic resonance (NMR) or infrared absorption spectrum in one aspect. In the rubber cured product, it is analyzed by an electron microscope or an atomic force microscope (AFM) in one aspect. The presence of the rubber bonded to the cellulose nanofibers is confirmed by analysis using NMR, infrared absorption spectrum, or Nano-IR in one aspect as a phase present in the vicinity of the cellulose nanofibers (as a region of a substance different from the matrix rubber in the rubber cured product in one aspect).

[0105] The third rubber preferably contains an aromatic vinyl monomer unit in that the dispersibility and orientation of the cellulose nanofibers are good due to the good affinity with the cellulose nanofibers.

[0106] The fourth rubber is preferably maleic anhydride-modified liquid polyisoprene from the viewpoints of miscibility with the matrix rubber and affinity with the cellulose nanofibers.

[0107] In the rubber composition, the amount of the third rubber with respect to 100 parts by mass of the fourth rubber is preferably 5 parts by mass or more, or 10 parts by mass or more, or 15 parts by mass or more from the viewpoint of favorably obtaining the advantages of the third rubber, and is preferably 300 parts by mass or less, or 280 parts by mass or less, or 260 parts by mass or less from the viewpoint of not hindering the advantages of the fourth rubber.

[0108] In the rubber composition, the amount of the third rubber with respect to 100 parts by mass of the cellulose nanofiber is preferably 5 parts by mass or more, or 10 parts by mass or more, or 15 parts by mass or more from the viewpoint of favorably obtaining the advantages of the third rubber, and is preferably 100 parts by mass or less, or 90 parts by mass or less, or 80 parts by mass or less from the viewpoint of favorably maintaining the mechanical properties of the molded article.

[0109] In the rubber composition, the amount of the fourth rubber with respect to 100 parts by mass of the cellulose nanofiber is preferably 10 parts by mass or more, or 15 parts by mass or more, or 20 parts by mass or more from the viewpoint of favorably obtaining the advantages of the fourth rubber, and is preferably 300 parts by mass or less, or 280 parts by mass or less, or 260 parts by mass or less from the viewpoint of suppressing excessive bonding or interaction between the fourth rubbers or between the fourth rubber and the cellulose nanofiber.

[0110] In the rubber composition, the content of the fourth rubber is preferably 5% by mass or more, or 7% by mass or more, or 10% by mass or more from the viewpoint of favorably obtaining the advantages of the fourth rubber, and is preferably 60% by mass or less, or 55% by mass or less, or 50% by mass or less from the viewpoint of suppressing excessive bonding or interaction between the fourth rubbers or between the fourth rubber and the cellulose nanofiber.

[0111] When forming a rubber composition using a masterbatch containing a first rubber, the total content ratio of the third and fourth rubbers in the masterbatch is 10% by mass or more, or 15% by mass or more, or 20% by mass or more from the viewpoint of improving the dispersibility and orientation of cellulose nanofibers, and preferably 90% by mass or less, or 85% by mass or less, or 80% by mass or less from the viewpoint of allowing a desired amount of cellulose nanofibers to be present to obtain a good reinforcing effect.

[0112] <Amount of matrix rubber and additive rubber> The total content ratio of the matrix rubber and additive rubber (which are typically cured products) in the deformation-following rubber member, or the total content ratio of the matrix rubber and additive rubber (which are typically uncured products) in the rubber composition used to form the deformation-following rubber member is preferably 40% by mass or more, or 50% by mass or more, or 60% by mass or more, and preferably 85% by mass or less, or 80% by mass or less, or 75% by mass or less, or 70% by mass or less from the viewpoint of containing other components in a desired amount.

[0113] For example, when the deformation-following rubber member contains a combination of butadiene rubber, styrene-butadiene rubber, and isoprene rubber, high wear resistance, grip performance, and tear strength can be achieved simultaneously. In a preferred embodiment, in the deformation-following rubber member or in the rubber composition, the amount ratio may be 60 to 70 parts by mass of butadiene rubber, 10 to 30 parts by mass of styrene-butadiene rubber, and 10 to 20 parts by mass of isoprene rubber per 100 parts by mass in total of the matrix rubber and additive rubber.

[0114] <Cellulose nanofibers> In one aspect, the deformation-following rubber member further includes cellulose nanofibers. Cellulose nanofibers have a high effect of increasing the modulus in a region with small strain. However, according to the studies of the present inventors, conversely, it has been empirically found that it is difficult to increase the modulus in a region with large strain. That is, according to the deformation-following rubber member containing cellulose nanofibers, in the stress-strain curve of the tensile test, the stress increase in the range from 50% or 100% strain to 300% strain can be reduced. This is advantageous for achieving both the difficulty of deformation during small deformation and the ease of deformation during large deformation.

[0115] Cellulose nanofibers are fibers obtained by refining a cellulose fiber raw material through a defibrillation process or the like. As the cellulose fiber raw material, natural cellulose and regenerated cellulose can be used. As natural cellulose, wood pulp obtained from wood species (hardwood or softwood), non-wood pulp obtained from non-wood species (cotton, bamboo, hemp, bagasse, kenaf, cotton linter, sisal, straw, etc.), cellulose fiber aggregates produced by animals (e.g., tunicates), algae, and microorganisms (e.g., acetic acid bacteria) can be used. As regenerated cellulose, regenerated cellulose fibers (viscose, cupra, tencel, etc.), cellulose derivative fibers, regenerated cellulose or ultrafine filaments of cellulose derivatives obtained by the electrospinning method can be used.

[0116] In one aspect, defibrillation is a dry or wet mechanical treatment, and preferably, it is 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. For defibrillation, a single device may be used one or more times, or a plurality of devices may be used one or more times each. 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 (stone mortar type crushers), ball mills, vibration mills, bead mills, conical refiners, disk refiners, single-axis, two-axis or multi-axis kneading machines and extruders.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] Examples of commonly used organic solvents include alcohols (such as methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, s-butanol, t-butanol, ethylene glycol, diethylene glycol, glycerin, etc.); ethers (such as propylene glycol monomethyl ether, 1,2-dimethoxyethane, diisopropyl ether, tetrahydrofuran, 1,4-dioxane, etc.); carboxylic acids (such as formic acid, acetic acid, lactic acid, etc.); esters (such as ethyl acetate, vinyl acetate, etc.); ketones (such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, etc.); nitrogen-containing solvents (dimethylformamide, dimethylacetamide, acetonitrile, etc.); and sulfur-containing solvents (dimethyl sulfoxide). One or more of these solvents may be used. In a typical embodiment, the liquid medium in the slurry is substantially only water.

[0121] In one embodiment, the number average fiber length L of the cellulose nanofibers is preferably 100 nm or more, or 500 nm or more, 1 μm or more, or 5 μm or more, or 10 μm or more, or 20 μm or more from the viewpoint of favorably expressing 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.

[0122] In one embodiment, 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.

[0123] 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 improving the mechanical properties of the rubber member containing the cellulose nanofibers well 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.

[0124] In the present disclosure, the fiber length, fiber diameter, and L / D ratio of the cellulose nanofibers are values measured by the following procedure using a scanning electron microscope (SEM). The aqueous dispersion of cellulose nanofibers is replaced with tert-butanol, diluted to 0.001 to 0.1% by mass, and dispersed using a high-shear homogenizer (for example, manufactured by IKA, trade name "Ultra Turrax T18") under the treatment conditions: rotation speed 15,000 rpm × 3 minutes, cast on an osmium-evaporated silicon substrate, and air-dried to obtain a measurement sample, which is measured with a high-resolution scanning electron microscope (SEM). Specifically, in an observation field with the magnification 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.

[0125] 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, and 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, since the structural mobility is relatively high, and by dispersing the cellulose nanofibers in rubber, a molded article with a lower linear expansion coefficient and more excellent strength and elongation during tensile and bending deformation can be obtained, 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.

[0126] 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 cured product 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, but from the perspective of production, the preferable upper limit is 99%.

[0127] When the cellulose nanofibers are of cellulose type I crystal (derived from natural cellulose), the crystallinity referred to here 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 the cellulose type I crystal I (amorphous) : Halo peak intensity due to the amorphous in the cellulose type I crystal, which is the peak intensity on the low-angle side (2θ = 18.0°) 4.5° lower than the diffraction angle of the 200 plane

[0128] Also, when the cellulose is of cellulose type II crystal (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 type II crystal 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

[0129] 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.

[0130] 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 range. From the viewpoint of processability, it is preferable that the degree of polymerization is not too high, and from the viewpoint of manifestation of mechanical properties, it is desirable that it is not too low.

[0131] 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)".

[0132] 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 points for thermal decomposition, particularly highly heat-resistant cellulose nanofibers and rubber compositions containing cellulose nanofibers and rubber can be obtained when the weight average molecular weight of the cellulose molecules in the cellulose nanofibers is large and at the same time the width of the molecular weight distribution is narrow. 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 manufacturing 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 and / or chemical treatments 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 and / or chemical treatments 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.

[0133] 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.

[0134] The alkali-soluble polysaccharides that the cellulose nanofibers may contain include, in addition to hemicellulose, β-cellulose and γ-cellulose. The alkali-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). The alkali-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 alkali-soluble polysaccharides in the cellulose nanofibers is low.

[0135] In one aspect, from the viewpoint of obtaining good dispersibility of the cellulose nanofibers, the average content rate of alkali-soluble polysaccharides in the cellulose nanofibers is preferably 20% by mass or less, or 18% by mass or less, or 15% by mass or less, or 12% by mass or less, 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.

[0136] The average content rate of alkali-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 alkali-soluble polysaccharide content rate is calculated three times for one sample, and the number average of the calculated alkali-soluble polysaccharide content rates is taken as the average content rate of alkali-soluble polysaccharides.

[0137] In one aspect, from the viewpoint of avoiding a decrease in the 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.

[0138] 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 Japanese Wood Research Society, pages 92-97, 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 3 times for one sample, and the number average thereof is taken as the average content rate of the acid-insoluble component.

[0139] [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 obtained by oxidizing the primary hydroxyl groups of cellulose. The chemically modified cellulose nanofibers may contain one or more types of modifying groups.

[0140] In a preferred embodiment, the chemical modification is acylation using an esterifying agent, and particularly preferably acetylation. As the esterifying agent, acid halides, acid anhydrides, and vinyl esters of carboxylic acids and carboxylic acids are preferred. 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.

[0141] [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 esterified cellulose nanofibers with a high thermal decomposition start temperature. Since an unmodified cellulose skeleton remains in the esterified cellulose nanofibers, it is possible to obtain esterified cellulose nanofibers 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.

[0142] 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 prepared, and the calibration curve Degree of substitution DS = 4.13 × IR index (1030) can be obtained by using it. IR index (1030)= H1730 / H1030 wherein, 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 is meant, with the lines connecting 1900 cm -1 and 1500 cm -1 and the lines connecting 800 cm -1 and 1500 cm -1 as the baseline.

[0143] The method for calculating the DS of the esterified cellulose nanofiber by solid NMR is as follows for the freeze-ground esterified cellulose nanofiber 13 perform 13C solid NMR measurement, and it can be obtained by the following formula from 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 appearing 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. to be used 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)

[0144] The thermal decomposition start temperature (T D ) of cellulose nanofibers is preferably, in one aspect, 200 °C or higher, or 210 °C or higher, 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 avoiding thermal degradation during melt-kneading and exhibiting good mechanical strength. 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.

[0145] [Temperature at 1% weight loss (T 1% ), weight loss rate at 250 °C (T 250℃ )] The temperature (T 1% ) at 1 wt% weight loss of cellulose nanofibers 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 good mechanical strength. T 1%Although a higher value is more preferable, 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.

[0146] The 250°C weight loss rate (T 250℃ ) of cellulose nanofibers is preferably, 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 from the viewpoint of avoiding thermal degradation during melt-kneading and exhibiting good mechanical strength. T 250℃ Although a lower value is more preferable, 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.

[0147] In the present disclosure, T D is a value obtained from a graph in thermogravimetric (TG) analysis where the horizontal axis is temperature and the vertical axis is the weight retention rate %. Starting from the weight of cellulose nanofibers at 150°C (state where moisture is almost removed) (weight loss amount 0 wt%), the temperature is further increased, and the temperature (T 1% ) at 1 wt% weight loss and the temperature (T 2% ) at 2 wt% weight loss are used to obtain a straight line. The temperature at the point where this straight line intersects the horizontal line (baseline) passing through the starting point of 0 wt% weight loss amount is defined as T D .

[0148] 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 above-described method of T D .

[0149] The 250°C 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 held 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 defined as W1, and it is calculated from the following formula. Weight change rate at 250 °C (%): (W1 - W0) / W0 × 100

[0150] [Porous sheet] Various physical properties (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.) of cellulose nanofibers may vary significantly depending on the form of the measurement sample. In order to perform measurements with stable reproducibility, a porous sheet without distortion is used as the measurement sample. The method for producing the porous sheet is as follows.

[0151] First, a concentrated cake of cellulose nanofibers with a solid content rate of 10 mass% or more is added to tert-butanol, and further subjected to a dispersion treatment with a mixer or the like until there are no aggregates. For 0.5 g of the cellulose nanofiber solid content weight, it is adjusted so that the concentration becomes 0.5 mass%. 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 distortion. 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.

[0152] 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 that has been left standing for 1 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

[0153] Various physical properties (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 content of acid-insoluble components, T D , T 1% , T 250℃ , DS, etc.) of the cellulose nanofibers contained in the rubber composition, rubber cured product, etc. are analyzed by the following method. The polymer component contained in the rubber composition, rubber cured product, etc. is dissolved in an organic or inorganic solvent capable of dissolving the polymer component, the cellulose nanofibers are separated, thoroughly washed with the solvent, and then the solvent is replaced with tert-butanol. Thereafter, the cellulose nanofiber tert-butanol slurry is analyzed using the same measurement method as the above method, and various physical properties of the cellulose nanofibers in the rubber composition and rubber cured product are calculated.

[0154] 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 dried 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 dried 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 Limited, trade name "MX-50").

[0155] ​The amount of cellulose nanofibers in the deformation-tracking rubber member is preferably 1% by mass or more, or 2% by mass or more, or 3% by mass or more from the viewpoint of obtaining a good reinforcing effect by the cellulose nanofibers, and is preferably 10% by mass or less, or 7% by mass or less, or 5% by mass or less from the viewpoint of ease of deformation during large deformation.

[0156] In the deformation-tracking rubber member, the amount of cellulose nanofibers relative to 100 parts by mass of the rubber is preferably 1 part by mass or more, or 2 parts by mass or more, or 3 parts by mass or more from the viewpoint of obtaining a good reinforcing effect by the cellulose nanofibers, and is preferably 10 parts by mass or less, or 7 parts by mass or less, or 5 parts by mass or less from the viewpoint of ease of deformation during large deformation.

[0157] <Additional filler> The deformation-tracking rubber member may, in one aspect, contain additional fillers other than cellulose nanofibers, but in a preferred aspect, it can be free of fillers other than cellulose nanofibers. Examples of the additional fillers include silica, carbon black, calcium carbonate, glass fiber, glass balloon, nylon fiber, carbon fiber, etc. The addition of silica can improve hardness, tensile strength, etc. When adding silica, the combined use of a silane coupling agent can improve the dispersibility of silica in the deformation-tracking rubber member and improve the wear resistance of the deformation-tracking rubber member. The amount of the additional filler may be, for example, 0 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 with respect to 100 parts by mass of the cellulose nanofibers, and may be, for example, 60 parts by mass or less, or 50 parts by mass or less, or 45 parts by mass or less, or 40 parts by mass or less, or 35 parts by mass or less, or 30 parts by mass or less. In a preferred aspect, the deformation-tracking rubber member can be free of hollow members such as glass balloons.

[0158] <Dispersant> In one aspect, the deformation-following rubber member contains a dispersant. In one aspect, it is more preferable from the viewpoint of more uniformly dispersing cellulose nanofibers in the deformation-following rubber member that the dispersant has a hydrophilic segment and a hydrophobic segment in the same molecule (i.e., is an amphiphilic molecule).

[0159] [Amphiphilic molecule] In the amphiphilic molecule, the hydrophilic segment is a portion that exhibits good affinity with cellulose nanofibers by containing 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 those having primary to tertiary amines and quaternary ammonium salts. Examples of the counter anion of the quaternary ammonium salt include halide ions such as hydroxide ion, fluoride ion, chloride ion, bromide ion, and iodide ion, 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.

[0160] 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 polyvinylpyrrolidone, 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 mechanical properties of the deformation-tracking rubber member, 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.

[0161] 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. The number of carbon atoms in 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. 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. are preferred. These hydrophobic segments may have either a linear structure or a branched structure. 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 multiple types of hydrophobic groups.

[0162] The structure of the amphiphilic molecule is not particularly limited. When the hydrophilic segment is A and the hydrophobic segment is B, linear copolymers such as AB-type block copolymers, ABA-type block copolymers, BAB-type block copolymers, etc., three-branched copolymers containing A and B, four-branched copolymers containing A and B, star copolymers containing A and B, monocyclic copolymers containing A and B, polycyclic copolymers containing A and B, cage copolymers containing A and B, graft copolymers containing A and B, etc. can be mentioned. When there are multiple hydrophilic segments in the molecule, the molecular structure may be a single type or a combination of two or more types. Similarly, when there are multiple hydrophobic segments in the molecule, the molecular structure may be a single type or a combination of two or more types.

[0163] (Surfactant) As the amphiphilic molecule, any of anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants can be used. The dispersant may be a polymer surfactant, a reactive surfactant, etc.

[0164] 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.

[0165] 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, alkanesulfonates, alkylbenzene sulfonates, alkylnaphthalene sulfonates; as sulfate esters, alkyl sulfates, fatty oil sulfate esters; and as phosphate esters, alkyl phosphates, polyoxyethylene alkyl ether phosphates.

[0166] Examples of cationic surfactants include amine salts, amidoamine salts, quaternary ammonium salts, imidazolinium salts, and the like. 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.

[0167] Examples of amphoteric surfactants include, for example, alkylamine oxides, alanines, imidazolinium betaines, amidobetaines, betaine acetates, and the like. Specifically, long-chain amine oxides, lauryl betaine, stearyl betaine, lauryl carboxymethyl hydroxyethyl imidazolinium betaine, lauryl dimethylaminoacetate betaine, fatty acid amidopropyl dimethylaminoacetate betaine, and the like can be mentioned.

[0168] [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 carboxyl group, an amino group, an ammonium group, a sulfonic acid group, a phosphoric acid group, and the like. As the hydrophilic polymer, one or more selected from the group consisting of cellulose derivatives (hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, etc.), polyalkylene glycols, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, carboxyvinyl polymer, cationized guar gum, water-soluble polyurethane, polymers containing a quaternary ammonium salt structure, amides, amines, and the like can be used. Among them, cellulose derivatives and polyalkylene glycols are more preferable, and polyalkylene glycols are particularly preferable.

[0169] The amount of the dispersant in the rubber composition for forming the deformation-following rubber member 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 with respect to 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.

[0170] In one aspect, the content rate of the dispersant in the rubber composition 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.

[0171] <Vulcanizing agent, vulcanization accelerator> The rubber composition 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 uncrosslinked rubber in the rubber composition. 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 compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, high molecular polysulfur compounds, etc.

[0172] The amount of the vulcanizing agent in the rubber composition 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 uncrosslinked rubber in the rubber composition.

[0173] Examples of the vulcanization accelerator include sulfenamide-based, guanidine-based, thiuram-based, aldehyde-amine-based, aldehyde-ammonia-based, thiazole-based, thiourea-based, dithiocarbamate-based vulcanization accelerators, etc. Zinc oxide, stearic acid, etc. may be used as the vulcanization aid. The amount of the vulcanization accelerator 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 uncrosslinked rubber in the rubber composition.

[0174] <Additives for rubber> The rubber composition 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. Further, as the rubber softener, one or more of process oil, extender oil, etc. may be used.

[0175] Note that the vulcanizing agent, vulcanization accelerator, and rubber additives are typically added in the process immediately before the cross-linking and molding process of the rubber, but the mode of addition is not limited to this.

[0176] <Additional Components> The rubber composition may further contain other additional components. Examples of the additional components include heat stabilizers, antioxidants, antistatic agents, colorants, etc. The content ratio of any additional component in the rubber composition 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.

[0177] ≪Manufacture of Shoes≫ One aspect of the present invention also provides a method for manufacturing the shoes of the present disclosure. In one aspect, the deformation-following rubber member contains cellulose nanofibers, and the method includes a step of manufacturing a masterbatch containing cellulose nanofibers and a first rubber, a step of mixing the masterbatch and a second rubber to obtain a rubber composition, a step of curing the rubber composition to obtain the deformation-following rubber member, and a step of assembling a shoe including an outsole having the deformation-following rubber member and an upper, and In another aspect, in the preparation of the rubber composition, it is also possible not to go through the preparation of the masterbatch as described above.

[0178] <Preparation of Rubber Composition> The rubber composition can be produced by a method of mixing rubber composition components including cellulose nanofibers, matrix rubber, optionally additive rubber, and optionally one or more additional components. Examples of the production method of the rubber composition include (1) a first step of obtaining a masterbatch which is a mixture containing cellulose nanofibers (which may be a slurry or a dry body) and a first rubber, and a second step of obtaining a rubber composition which is a mixture containing the masterbatch and a second rubber (hereinafter also referred to as the masterbatch method). (2) a method including a step of obtaining a rubber composition which is a mixture containing cellulose nanofibers (which may be a slurry or a dry body) and matrix rubber (hereinafter also referred to as the one-step mixing method). and the like.

[0179] The mixing conditions are not particularly limited. For example, the components constituting the rubber composition may be mixed by stirring means such as a rotating and revolving mixer, a planetary mixer, a propeller 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 rubber composition. Further, stirring may be performed under heating in order to efficiently perform shearing. In the masterbatch method of (1) above, by combining the first rubber with cellulose nanofibers in advance, the contact opportunity between the cellulose nanofibers and the second rubber becomes appropriate and uniform, so that the physical properties of the rubber composition or the rubber cured product may be improved more favorably.

[0180] The masterbatch and / or the rubber composition may be dried after obtaining them, and powders may be formed by controlling the drying conditions.

[0181] When mixing cellulose nanofibers with matrix rubber in the production of masterbatch or rubber composition, the cellulose nanofibers may be added in the form of slurry or dry body. In one aspect, after mixing the slurry of cellulose nanofibers with matrix rubber, the liquid medium in the slurry may be dried and removed to obtain a masterbatch or rubber composition containing cellulose nanofibers.

[0182] <Drying process> In one aspect: The dry body containing cellulose nanofibers, the masterbatch containing cellulose nanofibers, or the rubber composition containing cellulose nanofibers to be used for mixing with matrix rubber can be produced by drying the slurry containing cellulose nanofibers. The dryer is not particularly limited, and examples include kneader, planetary mixer, Henschel mixer, high-speed mixer, propeller mixer, ribbon mixer, single-screw or twin-screw extruder, Banbury mixer, freeze dryer, shelf dryer, spray dryer, fluidized bed dryer, drum dryer, etc.

[0183] From the viewpoints of drying efficiency, nano-dispersibility of cellulose nanofibers in the rubber composition, and forming a dry body 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 dry body containing cellulose nanofibers due to rapid drying of the slurry, the drying temperature may be, for example, 200 °C or lower, or 180 °C or lower, or 160 °C or lower, or 140 °C or lower, or 120 °C or lower, or 100 °C or lower. The drying temperature is the temperature of the heat source in contact with the slurry, and is defined, for example, as the surface temperature of the temperature control jacket of the drying device, the surface temperature of the heating cylinder, or the temperature of the hot air.

[0184] The pressure can be either atmospheric pressure or reduced pressure. From the perspective of forming a dried product containing cellulose nanofibers with excellent powder properties in terms of drying efficiency, nano-dispersibility, and macro-dispersibility of cellulose nanofibers in the rubber 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 perspective 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.

[0185] The concentration of cellulose nanofibers in the cellulose nanofiber-containing slurry subjected to the drying process is preferably 1% by mass or more, or 2% by mass or more, or 3% by mass or more, or 5% by mass or more, or 10% by mass or more, or 15% by mass or more, or 20% by mass or more, or 25% by mass or more from the perspective of process efficiency during drying. From the perspective 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.

[0186] In one aspect, the dried product containing cellulose nanofibers to be mixed with the matrix rubber may contain a third rubber and / or a fourth rubber, and any additional components (e.g., the dispersant described above), and may be added before, during, and / or after drying of the cellulose nanofiber-containing slurry. In one aspect, the third rubber and / or the fourth rubber, and / or any additional components 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 first rubber and the second rubber dissolve is preferable, and examples thereof include water-insoluble solvents such as chloroform, toluene, hexane, and cyclohexane.

[0187] [Liquid medium content] The liquid medium content of the dry body containing cellulose nanofibers, which is to be mixed with the matrix rubber, is preferably 50% by mass or less, or 40% by mass or less, or 30% by mass or less, or 20% by mass or less, or 10% by mass or less from the viewpoint of workability. The liquid medium content may be 0% by mass, but from the viewpoint of ease of production of the dry body containing cellulose nanofibers, for example, it may be 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.

[0188] [Average particle size] In one aspect, the average particle size of the dry body containing cellulose nanofibers, which is to be mixed with the matrix rubber, is preferably 1 μm or more, or 10 μm or more, 50 μm or more, or 100 μm or more, or 200 μm or more, or 500 μm or more from the viewpoint of ease of production, 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 rubber composition and the cellulose nanofibers being well dispersed in the rubber 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).

[0189] [Loose bulk density] In one aspect, the bulk density of the dry body containing cellulose nanofibers, which is to be mixed with matrix rubber, 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. From the viewpoints that the dry body containing cellulose nanofibers can easily disintegrate in the rubber composition and the cellulose nanofibers can be well dispersed in the rubber composition, and that the dry body containing cellulose nanofibers is not too heavy and poor mixing between the dry body containing cellulose nanofibers and the rubber composition can be avoided, it is preferably 0.85 g / cm 3 or less, or 0.80 g / cm 3 or less, or 0.75 g / cm 3 or less.

[0190] [Bulk density] In one aspect, the bulk density of the dry body containing cellulose nanofibers, which is to be mixed with matrix rubber, is controlled within a range useful for controlling the loose bulk density and compressibility within the scope of the present disclosure. In one aspect, preferably, it is 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 / cm3 less than or equal to 0.9 g / cm 3 less than or equal to 0.85 g / cm 3 or less.

[0191] [Degree of Compression] The degree of compression is a value calculated by Degree of Compression = (Compacted Bulk Density - Loose Bulk Density) / Compacted Bulk Density. The loose bulk density and the compacted 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 rubber composition, and suppressing the migration of the dispersant to the rubber, 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.

[0192] The above loose bulk density, compacted bulk density, and degree of compression are measured using a Powder Tester (Model No.: PT-X) manufactured by Hosokawa Micron Corporation. The number of tapping times for measuring the compacted bulk density is 180 times.

[0193] As a more specific example of the process sequence, the following can be exemplified. (1) Masterbatch method (i) Prepare a slurry containing cellulose nanofibers, optionally a third rubber, and optionally a dispersant → Dry to prepare a dry body → Prepare a masterbatch containing the dry body, a first rubber, and optionally a fourth rubber (as a coupling agent) → Prepare a rubber composition containing the masterbatch and a second rubber (ii) Prepare a slurry containing cellulose nanofibers and optionally a dispersant → Dry to prepare a dried body → Prepare a first masterbatch containing the dried body and optionally a third rubber → Prepare a second masterbatch containing the first masterbatch, a first rubber, and optionally a fourth rubber (as a coupling agent) → Prepare a rubber composition containing the second masterbatch and a second rubber (iii) Prepare a slurry containing cellulose nanofibers, a third rubber, a fourth rubber, and optionally a dispersant → Dry to prepare a dried body → Prepare a masterbatch containing the dried body and a first rubber → Prepare a rubber composition containing the masterbatch and a second rubber

[0194] (2) One - shot mixing method (i) Prepare a slurry containing cellulose nanofibers, optionally a third rubber, and optionally a dispersant → Dry to prepare a dried body → Prepare a rubber composition containing the dried body and a matrix rubber (ii) Prepare a slurry containing cellulose nanofibers and optionally a dispersant → Dry to prepare a first dried body → Prepare a second dried body containing the first dried body and a third rubber → Prepare a rubber composition containing the second dried body and a matrix rubber

[0195] In the rubber composition, the amount of the first rubber relative to 100 parts by mass of the second rubber is preferably 1 part by mass or more, 5 parts by mass or more, 10 parts by mass or more, or 15 parts by mass or more from the viewpoint of obtaining the advantages of the first rubber well, and preferably 300 parts by mass or less, 280 parts by mass or less, or 260 parts by mass or less from the viewpoint of not hindering the advantages of the second rubber.

[0196] In the rubber composition, the amount of the first rubber relative to 100 parts by mass of cellulose nanofibers is preferably 5 parts by mass or more, 10 parts by mass or more, or 15 parts by mass or more from the viewpoint of obtaining the advantages of the first rubber well, and preferably 200 parts by mass or less, 150 parts by mass or less, 120 parts by mass or less, 100 parts by mass or less, 90 parts by mass or less, or 80 parts by mass or less from the viewpoint of maintaining the mechanical properties of the molded body well.

[0197] In the rubber composition, the amount of the second rubber relative to 100 parts by mass of the cellulose nanofiber is preferably 10 parts by mass or more, or 15 parts by mass or more, or 20 parts by mass or more from the viewpoint of favorably obtaining the advantages of the second rubber, and is preferably 300 parts by mass or less, or 280 parts by mass or less, or 260 parts by mass or less from the viewpoint of suppressing excessive bonding or interaction between the second rubbers or between the second rubber and the cellulose nanofiber.

[0198] In the rubber composition, the content of the second rubber is preferably 5% by mass or more, or 7% by mass or more, or 10% by mass or more from the viewpoint of favorably obtaining the advantages of the second rubber, and is preferably 60% by mass or less, or 55% by mass or less, or 50% by mass or less from the viewpoint of suppressing excessive bonding or interaction between the second rubbers or between the second rubber and the cellulose nanofiber.

[0199] In the rubber composition, the total content of the first and second rubbers is 10% by mass or more, or 15% by mass or more, or 20% by mass or more from the viewpoint of improving the dispersibility of the cellulose nanofiber, and is preferably 90% by mass or less, or 85% by mass or less, or 80% by mass or less from the viewpoint of obtaining a desired amount of cellulose nanofiber and a good reinforcing effect. In the above manner, a rubber composition for a deformation-following rubber member can be produced.

[0200] ≪Manufacture of Deformation-Following Rubber Member and Outsole≫ In one aspect, a rubber composition for a deformation-following rubber member is cured alone or together with an additional rubber composition for an additional member of an outsole in a desired shape to obtain an outsole having a deformation-following rubber member (as a rubber cured product). For example, a rubber composition sheet obtained by kneading and sheeting the rubber composition components may be vulcanized and pressed under conditions conforming to JIS K6299 while placed in a mold of a desired shape. The combination method and molding method of the rubber composition are not particularly limited and may be selected according to the desired outsole. The molding method is not limited to these, but (1) A method for obtaining an outsole by curing a rubber composition for a deformation-tracking rubber member alone or together with an additional rubber composition before, during, and / or after molding when molding, (2) A method for obtaining an outsole by curing a rubber composition for a deformation-tracking rubber member to form a deformation-tracking rubber member, and then combining this with separately formed additional members by adhesion or the like, etc. are exemplified. The molding may be performed by injection molding, extrusion molding, extrusion profile molding, blow molding, compression molding, etc.

[0201] <Shoe assembly> The outsole obtained as described above may be combined with an upper, a shank (when disposed outside the outsole), and any members such as a midsole, an insole, etc. by conventionally known methods such as adhesion and sewing to manufacture the shoe of this embodiment. For example, a method can be exemplified in which a plurality of sheets for the upper cut with a die are sewn together, then the upper is formed by wrapping and molding around a foot mold, a shank is sandwiched between the outsole and the midsole and these are adhered to form a sole, and the foot mold is removed after adhering the upper and the sole.

Examples

[0202] Hereinafter, the exemplary aspects of the present invention will be further described with reference to examples, but the present invention is not limited to these aspects.

[0203] ≪Evaluation method≫ <Evaluation of cellulose nanofibers> [Production of porous sheet] First, the concentrated cake was added to tert-butanol, and further dispersed 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 nanofibers. 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 together with the filter paper, 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 used as the measurement sample. After measuring the basis weight W (g / m 2 ) of the sample left standing for 1 day in an environment of 23 °C and 50% RH, the air permeability resistance R (sec / 100 ml) was measured using a Wangyan 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

[0204] [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. Next, separated the water and the solid content by centrifugation. Subsequently, added 20 mL of acetone, gently stirred it, and left it for one day. Next, separated the acetone and the 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 the 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 the 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: in terms of pullulan For acetylated cellulose nanofibers, the weight average molecular weight (Mw), number average molecular weight (Mn), and Mw / Mn ratio of the raw material before acetylation were adopted.

[0205] [Crystallinity] Performed X-ray diffraction measurement of the porous sheet, and calculated the crystallinity from the following formula. Crystallinity (%) = [I (200) -I (amorphous) / I (200) × 100 I (200) : Diffraction peak intensity due to the 200 plane (2θ = 22.5°) in cellulose I-type crystal I (amorphous): The intensity of the halo peak due to the amorphous phase in cellulose I crystals, which is the peak intensity on the low-angle side by 4.5° from the diffraction angle of the 200 plane (2θ = 18.0°) (X-ray diffraction measurement conditions) Apparatus MiniFlex (manufactured by Rigaku Corporation) Axis of operation 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: A porous sheet was attached onto the sample holder

[0206] [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, air-dried, and measured with a high-resolution scanning electron microscope (manufactured by Hitachi High-Technologies Corporation, Regulus8220). The measurement was performed by adjusting the magnification so that at least 100 cellulose fibers were observed, measuring the minor axis (D) of 100 randomly selected cellulose fibers, and calculating the arithmetic mean of the 100 cellulose fibers.

[0207] [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 using the device program.

[0208] <Evaluation of the CNF dried product> The following evaluations were performed on the CNF dried body. For the measurement, a powder tester (model number: PT-X) manufactured by Hosokawa Micron Corporation was used. [Loose bulk density] It was measured by supplying the CNF dried body into a cylindrical container with a volume of 100 mL (material: stainless steel) until it was heaped up, shaving the upper surface, and weighing it. In the general usage method of the powder tester, a sieve and a funnel are set on the cylindrical container to supply the sieved powder. However, in this example, the powder was directly supplied by free fall so as to be uniform without setting the sieve. [Compacted bulk density] After shaving the upper surface and weighing it to measure the loose bulk density, a cap (a spare part of the powder tester manufactured by Hosokawa Micron Corporation) was further fitted on this container, and the powder was added up to the upper edge and tapping was performed 180 times. After completion, the cap was removed and the powder was shaved on the upper surface of the container and weighed to measure it. [Compressibility] The compressibility was calculated by Compressibility = (Compacted bulk density - Loose bulk density) / Compacted bulk density.

[0209] <Evaluation of rubber member (rubber cured product)> [Tensile strength, modulus (M50, M100, M300, ΔM50, ΔM100, ΔM300)] The evaluation was carried out in accordance with the tensile test method of JIS K-6251. Using a tensile testing machine (manufactured by Toyo Seiki Seisaku-sho, Ltd., model number Strograth AE Elastomer AE2), the tensile strength, tensile stress at 50% elongation (50% modulus, M50), tensile stress at 100% elongation (100% modulus, M100), and tensile stress at 300% elongation (300% modulus, M300) were measured. ΔM50 is the difference between M50 and the stress at 0% strain (substantially equivalent to M50), ΔM100 is the difference between M100 and the stress at 0% strain (substantially equivalent to M100), and ΔM300 is the difference between M300 and M100.

[0210] [Shore A hardness] The evaluation was carried out in accordance with JIS K6253-3. The hardness of the vulcanizate was measured using a type A durometer (manufactured by Teclock Corporation, model number GX-02). The measurement was performed at 25°C.

[0211] [Tear strength] Evaluation was carried out in accordance with JIS K-6252. An angled test piece was prepared, and using a tear tester (manufactured by Toyo Seiki Seisakusho, model number Strograth AE Elastomer AE2), the maximum tearing force until the test piece was cut was measured.

[0212] [Wear resistance] Evaluation was carried out in accordance with JIS K-6264-2. A cylindrical test piece with a diameter of 16 mm and a height of 10 mm was fabricated by compression molding. Using a DIN wear tester (manufactured by Ueshima Seisakusho, model number DATAB-6112), the test was conducted in air at room temperature (25°C), method B (with rotation), a wear distance of 40 m, and a load of 10 N, and the volume of the test piece before and after the wear test was measured.

[0213] [Storage elastic modulus, loss tangent] Regarding the rubber cured sheet, using a viscoelastic test apparatus (manufactured by TA Instruments, model number ARES-G2), the storage elastic modulus and loss tangent (tanδ) at 50°C, a frequency of 10 Hz, and a strain of 3% were evaluated by a torsion method.

[0214] ≪Materials used≫ <Matrix rubber (first and second rubbers)> Conjugated diene polymer (SBR-1): Asaprene Y031 (available from Asahi Kasei Corporation) Natural rubber (NR-1): RSS No.3 (producer: UNIMAC RUBBER CO., LTD. (Thailand), supplier: Marubeni Techno Rubber)

[0215] Conjugated diene polymer (SBR-2): Manufactured by the following procedure. One autoclave with an internal volume of 10 L, a ratio of internal height (L) to diameter (D) of 4.0, an inlet at the bottom, an outlet at the top, and equipped with a stirrer and a jacket for temperature control was used. Further, one static mixer was connected in front of the raw material inlet of the reactor. 1,3-butadiene from which impurities such as moisture had been removed in advance was mixed at 20.2 g / min, styrene at 16.8 g / min, and n-hexane at 137.6 g / min to obtain a mixed solution. Immediately before this mixed solution entered the first reactor, n-butyllithium for impurity inactivation treatment was supplied, mixed with a static mixer, and then continuously supplied to the bottom of the first reactor. Further, 2,2-bis(2-oxolanyl)propane as a polar substance was continuously supplied to the bottom of the reactor at 0.320 phm, and NBL (normal butyllithium) as a polymerization initiator was supplied at 0.102 phm, and the temperature inside the reactor was maintained at 82 °C to obtain a rubber solution.

[0216] The rubber solution produced in the reactor was supplied from the top of the reactor to a static mixer, and in front of the static mixer, M1 (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane) was continuously supplied as a modifier at a ratio of 1.0 equivalent with respect to the lithium of NBL supplied as a polymerization initiator (however, the addition amount was calculated assuming that 4 mol of NBL reacts with 1 mol of M1) to carry out the reaction and obtain a conjugated diene polymer (SBR-2).

[0217] <Additive rubber (third rubber)> Liquid rubber: Ricon184 manufactured by Kuraray Co., Ltd. (liquid butadiene-styrene random copolymer, Mn = 9,400)

[0218] <Additive rubber (fourth rubber)> Modified liquid rubber-1: LIR-403 manufactured by Kuraray Co., Ltd. (maleic anhydride-modified liquid polyisoprene, Mn = 34,000, number of modified groups per molecular chain is 3) Modified liquid rubber-2: Ricon184MA6 manufactured by Kuraray Co., Ltd. (maleic anhydride-modified liquid styrene-butadiene copolymer, Mn = 9,200, number of modified groups per molecular chain is 6) Modified Liquid Rubber - 3: Ricon131MA20 manufactured by Kraiburg (Maleic Anhydride Modified Liquid Polybutadiene, Mn = 7,000, number of modifying groups per molecular chain is 11)

[0219] <Cellulose Nanofiber (CNF): Microfibrillar Cellulose> 3 parts by mass of cotton linter pulp was immersed in 27 parts by mass of water and dispersed with a pulper. 30 parts by mass of the cotton linter pulp slurry treated with the pulper (including 3 parts by mass of cotton linter pulp) was mixed with 170 parts by mass of water and dispersed in water (solid content ratio 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, with a clearance between disks of 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 under an operating pressure of 100 MPa using a high-pressure homogenizer (NSO15H manufactured by Niro Soavi, Italy) to obtain a fine cellulose fiber slurry (solid content concentration: 1.5% by mass). Then, it was concentrated to a solid content ratio of 10% by mass with a dehydrator to obtain a concentrated cake of CNF. The weight average molecular weight (Mw) of this cellulose nanofiber was 240,000, Mw / Mn was 8.6, crystallinity was 88%, number average fiber diameter was 53 nm, and specific surface area was 50 m 2 / g.

[0220] <Dispersant> Nonionic Dispersant: Sunnix GL-3000 manufactured by Sanyo Chemical Industries, Ltd. (Polyoxyethylene Polyoxypropylene Triol)

[0221] <Silica> Product name "Ultrasil VN3" manufactured by Evonik <Silane Coupling Agent> Product name "Si69" (Bis(triethoxysilylpropyl)disulfide) manufactured by Evonik

[0222] <Vulcanization Aid> Zinc Oxide: Available from Fuji Film Wako Pure Chemical Corporation Stearic Acid: Available from Fuji Film Wako Pure Chemical Corporation <Antioxidant> No Crack 6C: N-Phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (Available from Ouchi Shinko Chemical Industrial Co., Ltd.) <Vulcanization Accelerator> Vulcanization Accelerator - 1: Sunceler NS-G (N-(tert-butyl)-2-benzothiazolesulfenamide (Available from Sanshin Chemical Industry Co., Ltd.)) Vulcanization Accelerator - 2: Sunceler M (2-mercaptobenzothiazole (Available from Sanshin Chemical Industry Co., Ltd.))

[0223] ≪Production of CNF Dry Body≫ Purified water was added to the above CNF (concentrated cake of CNF) to obtain an aqueous dispersion with a final cellulose nanofiber content of 5% by mass. To this, liquid rubber (the third rubber) and a nonionic dispersant were added, and an aqueous dispersion was prepared so that the final composition was 90% by mass of water, 5% by mass of cellulose nanofiber, 2.86% by mass of liquid rubber, and 2.14% by mass of nonionic dispersant. The aqueous dispersion was mixed for 5 minutes using a Shin-Kee Co., Ltd. rotation-revolution mixer ARE-310 to obtain a dispersion of the cellulose nanofiber composition. The obtained dispersion was dried at 80 °C using an SPH-201 manufactured by Espec Corporation to obtain a dry body. The obtained dry body was pulverized for 30 seconds using a Mini Speed Mill MS-05 manufactured by Labonekt Co., Ltd. to obtain a CNF dry body (CNF-1). The loose bulk density of the dry body was 0.43 g / cm 3 , and the packed bulk density was 0.56 g / cm 3 , and the compressibility was 18.4%.

[0224] ≪Production of Masterbatch≫ [Production Examples 1 to 11] A sealed kneader (internal volume: 0.35 L) equipped with a temperature control device was used. Under the conditions of a filling rate of 65% and a rotor rotation speed of 30 to 100 rpm, a conjugated diene polymer or natural rubber (first rubber), a CNF dried product, and a modified liquid rubber (fourth rubber) were kneaded according to the composition shown in Table 1. At this time, the temperature of the sealed mixer was controlled, and a masterbatch was obtained at a discharge temperature of 155 to 160°C.

[0225] ≪Manufacture of rubber member (rubber cured product)≫ [Examples 1 to 17: Using masterbatch] A sealed kneader (internal volume: 0.35 L) equipped with a temperature control device was used. As the first-stage kneading, at a filling rate of 65%, according to the formulation shown in Table 2, a conjugated diene polymer or natural rubber (second rubber), a masterbatch, silica, a silane coupling agent, zinc white, stearic acid, and an antioxidant were added and kneaded at 140°C for 3 minutes. Next, as the second-stage kneading, the obtained kneaded product was cooled to room temperature and then kneaded again at 140°C for 3 minutes to improve the dispersion of cellulose nanofibers. After cooling, sulfur and a vulcanization accelerator were added and kneaded on an open roll set at 70°C, and formed into a sheet. Thereafter, the sheet-like kneaded product was vulcanized with a vulcanization press at 160°C for 20 minutes using a mold with a thickness of 2.0 mm to obtain a rubber cured product sheet. Various evaluations were performed on the obtained rubber cured product sheet. The results are shown in Table 2. Separately, the sheet before vulcanization was used for the manufacture of shoes.

[0226] [Examples 18 to 28, Comparative Examples 1 to 3: Without using masterbatch] A sealed kneader (internal volume: 0.35 L) equipped with a temperature control device was used. As the first-stage kneading, at a filling rate of 65%, according to the formulation shown in Table 3, a conjugated diene polymer or natural rubber (matrix rubber), CNF dry matter, modified liquid rubber (fourth rubber), silica, silane coupling agent, zinc white, stearic acid, and antioxidant were added and kneaded at 140 °C for 3 minutes. Next, as the second-stage kneading, the obtained kneaded material was cooled to room temperature and then kneaded again at 140 °C for 3 minutes to improve the dispersion of cellulose nanofibers. After cooling, sulfur and a vulcanization accelerator were added and kneaded on an open roll set at 70 °C, and then molded into a sheet. Thereafter, the sheet-like kneaded material was vulcanized in a mold with a thickness of 2.0 mm at 160 °C for 20 minutes using a vulcanization press to obtain a rubber cured sheet. Various evaluations were performed on the obtained rubber cured sheet. The results are shown in Table 3. Separately, the sheet before vulcanization was used for shoe manufacturing.

[0227] ≪Shoe Manufacturing≫ The sheet-like kneaded material before vulcanization manufactured above was attached to a commercially available shoe (business shoes) by the following procedure. The outsole of a commercially available shoe (business shoes) was removed. This shoe had a steel shank embedded between the outsole and the insole. Next, the sheet-like kneaded material before vulcanization manufactured in the example or comparative example was attached to a mold for the outsole so that the roll direction was the length direction of the sole, and vulcanized at 160 °C for 20 minutes using a vulcanization press to obtain an outsole. The obtained outsole was attached to the above shoe to obtain a shoe of the example or comparative example.

[0228] [Evaluation of Actual Shoes] The wearer who wore the manufactured shoe was made to walk to evaluate the walking comfort. Among 10 wearers, the evaluation was made according to the following criteria based on the number of people who answered that the walking comfort was excellent. A: The number of people who answered that the walking comfort was excellent was 7 or more B: The number of people who answered that the walking comfort was excellent was 5 or more and less than 7 C: The number of people who answered that the walking comfort was excellent was less than 5

[0229]

Table 1

[0230]

Table 2

[0231]

Table 3

Industrial Applicability

[0232] The present invention can be suitably applied to various shoes that require good shoe shape retention, ease of operation, and good durability.

Claims

1. A shoe comprising an outsole and an upper, wherein the shoe comprises a shank, wherein the outsole has a deformation-tracking rubber member satisfying the following formula: 0.1 < (ΔM300 / 200) / (ΔM50 / 50) < 0.7 (wherein ΔM50 and ΔM300 are the amounts of change in stress at strains of 0% to 50% and 100% to 300% in the stress-strain curve of the tensile test, respectively).) A shoe having a deformation-tracking rubber member that satisfies the formula.

2. The shoe according to claim 1, wherein the deformation-tracking rubber member satisfies the following formula: 2.0 MPa < M50 < 7.0 MPa 1.5 < M300 / M50 < 5.0 (wherein M50 and M300 are the stresses at strains of 50% and 300% in the tensile test, respectively).) The shoe according to claim 1, wherein the shoe satisfies the formula.

3. The shoe according to claim 1 or 2, wherein the deformation-tracking rubber member satisfies the following formula: 3.5 MPa < M100 < 10 MPa 1.0 < M300 / M100 < 2.5 (wherein M100 and M300 are the stresses at strains of 100% and 300% in the tensile test, respectively).) The shoe according to claim 1 or 2, wherein the shoe satisfies the formula.

4. The shoe according to claim 1 or 2, wherein the deformation-tracking rubber member is present at least in the forefoot region.

5. The shoe according to claim 4, wherein the deformation-tracking rubber member is present at least in the forefoot region and the midfoot region.

6. The shoe according to claim 5, wherein the deformation-tracking rubber member extends across the forefoot region and the midfoot region.

7. The shoe according to claim 1 or 2, wherein the shank is present in the midfoot region of the outsole as part of the outsole, and the deformation-tracking rubber member is in contact with the shank.

8. The shoe according to claim 1 or 2, further comprising a midsole, wherein the shank is disposed between the outsole and the midsole.

9. The shoe according to claim 1 or 2, wherein the deformation-tracking rubber member has a concavo-convex pattern on the exposed surface of the outsole.

10. The shoe according to claim 1 or 2, wherein the deformation-tracking rubber member contains one or more selected from the group consisting of butadiene rubber, styrene-butadiene rubber, isoprene rubber, acrylonitrile-butadiene rubber, and natural rubber.

11. The shoe according to claim 1 or 2, wherein the deformation-tracking rubber member further contains cellulose nanofibers.

12. The shoe according to claim 1 or 2, wherein the deformation-tracking rubber member does not contain hollow fillers.

13. A method for manufacturing a shoe according to claim 1 or 2, wherein the deformation-following rubber member contains cellulose nanofibers, the method comprises a step of manufacturing a masterbatch containing cellulose nanofibers and a first rubber, a step of mixing the masterbatch and a second rubber to obtain a rubber composition, a step of curing the rubber composition to obtain the deformation-following rubber member, and a step of assembling a shoe comprising an outsole having the deformation-following rubber member and an upper, The method includes.

Images