WO2019188104A1

WO2019188104A1 - Fiber-reinforced vulcanized rubber composition and production method therefor

Info

Publication number: WO2019188104A1
Application number: PCT/JP2019/009214
Authority: WO
Inventors: 山田　昌宏; 阪本　浩規; 真之廣田; 佑美細木; 村瀬　裕明
Original assignee: 大阪瓦斯株式会社; 大阪ガスケミカル株式会社
Priority date: 2018-03-30
Filing date: 2019-03-08
Publication date: 2019-10-03
Also published as: JPWO2019188104A1

Abstract

The present invention prepares a rubber composition by using a rubber ingredient (A) in combination with modified cellulose nanofibers (B) including, bonded thereto, a fluorene compound (B1) having aryl groups at the 9,9-position. The fluorene compound (B1) may be a compound represented by formula (1). (In formula (1), rings Z each represent an arene ring, R¹ and R² each represent a substituent, X¹ represents a heteroatom-containing functional group, k is an integer of 0-4, n is an integer of 1 or larger, and p is an integer of 0 or larger.) This rubber composition is excellent in terms of mechanical properties including strength, elongation, and hardness.

Description

Fiber-reinforced vulcanized rubber composition and method for producing the same

The present invention relates to a vulcanized rubber composition reinforced with cellulose nanofibers modified with a 9,9-bisarylfluorene skeleton and a method for producing the same.

Cellulose, which is a fiber derived from natural products such as plants, has a low environmental load, is a sustainable resource, and has excellent properties such as high elastic modulus, high strength, and low linear expansion coefficient. Therefore, it is used for a wide range of applications, for example, materials such as paper, film and sheet, and resin composite materials (for example, resin reinforcing agents). Also in the rubber composition, cellulose is added as a reinforcing agent to the rubber composition in order to improve the mechanical properties of the rubber.

Japanese Patent Application Laid-Open No. 2005-75856 (Patent Document 1) discloses a finely powdered cellulose fiber prepared from natural plant fibers and having an average particle size of 100 μm as a rubber composition capable of achieving both excellent low heat generation and synthesis. A tire rubber composition containing 2 to 100 parts by weight of diene rubber with respect to 100 parts by weight of diene rubber is disclosed. Japanese Patent Application Laid-Open No. 2005-133025 (Patent Document 2) discloses a rubber composition having excellent abrasion resistance, having 5 to 75 parts by weight of starch and a fiber diameter of 1 μm or less with respect to 100 parts by weight of the diene rubber component. A rubber composition comprising 0.1 to 40 parts by weight of bacterial cellulose is disclosed.

However, in these rubber compositions, since the compatibility between rubber and cellulose is low, rubber properties such as breaking properties are deteriorated.

Therefore, in order to improve the compatibility between rubber and cellulose, Japanese Patent No. 4581116 (Patent Document 3) describes a vulcanized rubber composition having excellent breaking characteristics and low energy loss at the interface between rubber and cellulose. 1 to 50 parts by weight (more preferably, chemically modified microfibril cellulose having an average fiber diameter of 4 nm to 1 μm with respect to 100 parts by weight of a rubber component composed of at least one of natural rubber, modified natural rubber, acrylonitrile butadiene rubber and polybutadiene rubber. 7 to 15 parts by weight) is disclosed. This document describes acetylation, alkyl esterification, complex esterification, β-ketoesterification, and arylcarbamation as chemical modification methods for microfibril cellulose.

However, even with this rubber composition, mechanical properties such as strength, elongation and hardness cannot be improved. Furthermore, in order to improve these characteristics, a large amount of chemically modified cellulose is required, and it is difficult to achieve both characteristics.

Japanese Patent Laying-Open No. 2005-75856 (Claim 1 and paragraph [0007]) JP 2005-133025 A (Claims) Japanese Patent No. 4581116 (claims, paragraphs [0003] [0006] [0039])

Therefore, an object of the present invention is to provide a vulcanized rubber composition capable of improving mechanical properties such as strength, elongation and hardness, and a method for producing the same.

Another object of the present invention is to provide a vulcanized rubber composition capable of improving heat resistance and solvent resistance and a method for producing the same.

As a result of intensive studies to achieve the above-mentioned problems, the present inventors have reinforced rubber composition by reinforcing rubber components with modified cellulose nanofibers to which a compound having a 9,9-bis (aryl) fluorene skeleton is bound. The present inventors have found that mechanical properties such as strength, elongation, and hardness of a product can be improved.

That is, the vulcanized rubber composition of the present invention includes a rubber component (A) and a modified cellulose nanofiber (B) to which a fluorene compound (B1) having an aryl group at the 9th and 9th positions is bonded. The fluorene compound (B1) may be a compound represented by the following formula (1).

Wherein ring Z is an arene ring, R ¹ and R ² are substituents, X ¹ is a heteroatom-containing functional group, k is an integer of 0 to 4, n is an integer of 1 or more, and p is an integer of 0 or more. Show).

In the formula (1), X ¹ is a group — [(OA) _m1 -Y ¹ ] (wherein A is an alkylene group, Y ¹ is a hydroxyl group or a glycidyloxy group, and m1 represents an integer of 0 or more) It may be. The ratio of the fluorene compound (B1) may be about 0.01 to 33% by weight with respect to the total amount of the modified cellulose nanofiber (B). The modified cellulose nanofiber (B) may have an average fiber diameter of about 3 to 500 nm. The rubber component (A) may contain a diene rubber and / or an olefin rubber. The ratio of the modified cellulose nanofiber (B) may be about 0.1 to 30 parts by weight with respect to 100 parts by weight of the rubber component (A). The vulcanized rubber composition may further contain a reinforcing agent (C) and a processing aid (D).

The present invention provides a kneading step of kneading the rubber component (A), the modified cellulose nanofiber (B) in which the fluorene compound (B1) having an aryl group at the 9th and 9th positions is bonded and / or its raw material. Also included is a method for producing the vulcanized rubber composition, which includes a vulcanization step of vulcanizing the kneaded composition to obtain a vulcanized rubber composition. The raw material may be a fluorene compound (B1) and unmodified cellulose nanofibers. In the kneading step, the modified cellulose nanofiber (B) and / or its raw material dispersed in advance in the processing aid (D) may be kneaded with the rubber component (A).

In the present invention, since the rubber component is reinforced with modified cellulose nanofibers to which a compound having a 9,9-bis (aryl) fluorene skeleton is bonded, the modified cellulose nanofibers can be uniformly dispersed in the rubber, and the vulcanized rubber composition Mechanical properties such as strength, elongation and hardness of objects can be improved. Furthermore, the obtained vulcanized rubber composition has high heat resistance and solvent resistance, and can suppress swelling of rubber even when it contains a processing aid such as a solvent or a softening agent.

FIG. 1 is a scanning electron microscope (SEM) photograph of cellulose nanofibers used in the examples.

The vulcanized rubber composition of the present invention includes a rubber component (A) and a modified cellulose nanofiber (B) to which a fluorene compound (B1) having an aryl group at the 9th and 9th positions is bonded.

[Rubber component (A)]
The rubber component (A) is not particularly limited, and a conventional rubber component can be used. Examples of conventional rubber components include diene rubber, olefin rubber, acrylic rubber (ACM, ANM), butyl rubber (IIR), epichlorohydrin rubber (CO), polysulfide rubber (OT, EOT), and urethane rubber. (U), silicone rubber (Q), fluorine rubber (FFKM, FKM), sulfur-containing rubber and the like. These rubber components can be used alone or in combination of two or more. Of these rubber components, diene rubbers and / or olefin rubbers are preferred from the viewpoint of a large improvement effect by the modified cellulose nanofiber (B).

Examples of the diene rubber include natural rubber (NR), epoxidized natural rubber, polybutadiene [eg, butadiene rubber (BR), 1,2-polybutadiene (VBR), etc.], isoprene rubber (IR), chloroprene rubber (CR ), Acrylonitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), and the like. These diene rubbers may be hydrogenated rubber (for example, hydrogenated BR, hydrogenated NBR, hydrogenated SBR, etc.). These diene rubbers can be used alone or in combination of two or more.

Examples of the olefin rubber include ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM), ethylene-butene rubber, ethylene-1-butene-diene rubber, propylene-1-butene-diene rubber, polyisobutylene rubber, ethylene -Vinyl acetate rubber, maleic acid modified ethylene-propylene rubber (M-EPM), chlorosulfonated polyethylene (CSM), chlorinated polyethylene (CM), maleic acid modified chlorinated polyethylene (M-CM) and the like. Examples of the diene unit (non-conjugated diene unit) contained in the olefin rubber include units derived from dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, methylene norbornene, and ethylidene norbornene. These olefin rubbers can be used alone or in combination of two or more.

The copolymer rubber may be a random or block copolymer, and examples of the block copolymer include a copolymer having an AB type, ABA type, tapered type, or radial teleblock type structure. .

Of these, diene rubbers such as SBR and NBR and olefin rubbers such as EPDM are preferred.

The Mooney viscosity of the unvulcanized rubber component can be appropriately selected depending on the rubber type, and may be 30 or more (for example, about 30 to 80) in the case of a diene rubber, or 20 or more (for example, in the case of an olefin rubber) Or about 40 (for example, about 40 to 80) in the case of an olefin-based rubber composition containing carbon black as a reinforcing agent.

In the present specification and claims, the Mooney viscosity can be measured according to JIS K6300.

[Modified cellulose nanofiber (B)]
(Fluorene compound (B1))
The fluorene compound (B1) having an aryl group at the 9,9-position is a compatibilizing agent or dispersion for uniformly dispersing cellulose nanofibers in the rubber component as a functional group constituting the modified cellulose nanofiber (B). By functioning as an agent and uniformly dispersing cellulose nanofibers in the rubber component (A), the mechanical properties of the vulcanized rubber composition can be greatly improved.

Such a fluorene compound may be a compound having a 9,9-bisarylfluorene skeleton, and may be, for example, a fluorene compound represented by the formula (1).

In the formula (1), examples of the arene ring represented by the ring Z include a monocyclic arene ring such as a benzene ring, a polycyclic arene ring, and the like. The polycyclic arene ring includes a condensed polycyclic arene. A ring (fused polycyclic hydrocarbon ring), a ring assembly arene ring (ring assembly aromatic hydrocarbon ring), and the like are included.

Examples of the condensed polycyclic arene ring include a condensed bicyclic arene ring (for example, a condensed bicyclic C _10-16 arene ring such as a naphthalene ring), a condensed tricyclic arene (for example, an anthracene ring, a phenanthrene ring, etc.) And condensed bi- to tetracyclic arene rings. Preferred examples of the condensed polycyclic arene ring include a naphthalene ring and an anthracene ring, and a naphthalene ring is particularly preferable.

Examples of the ring-assembled arene ring include a bearene ring [for example, a bi-C _6-12 arene ring such as a biphenyl ring, a binaphthyl ring, a phenylnaphthalene ring (for example, a 1-phenylnaphthalene ring, a 2-phenylnaphthalene ring, etc.), A ring (for example, a tel C _6-12 arene ring such as a terphenylene ring) can be exemplified. Preferred ring-assembled arene rings include bi-C _6-10 arene rings, particularly biphenyl rings.

The two rings Z substituted at the 9-position of fluorene may be different or the same, but are usually the same ring in many cases. Of the rings Z, a benzene ring, a naphthalene ring, a biphenyl ring (particularly a benzene ring) and the like are preferable.

In addition, the substitution position of the ring Z substituted at the 9-position of fluorene is not particularly limited. For example, when the ring Z is a naphthalene ring, the group corresponding to the ring Z substituted at the 9-position of fluorene may be a 1-naphthyl group, a 2-naphthyl group, or the like.

Examples of the hetero atom-containing functional group represented by X ¹ include a functional group having at least one selected from oxygen, sulfur and nitrogen atoms as a hetero atom. The number of heteroatoms contained in such a functional group is not particularly limited, but may be usually 1 to 3, preferably 1 or 2.

Examples of the functional group include a group — [(OA) _m1 —Y ¹ ] (wherein Y ¹ is a hydroxyl group, a glycidyloxy group, an amino group, an N-substituted amino group, or a mercapto group, and A is an alkylene group. M1 is an integer of 0 or more), a group — (CH ₂ ) _m2 —COOR ³ (wherein R ³ is a hydrogen atom or an alkyl group, and m2 is an integer of 0 or more).

In the group-[(OA) _m1 -Y ¹ ], examples of the N-substituted amino group for Y ¹ include N-monoalkylamino groups such as methylamino and ethylamino groups (N-monoC _1-4 alkylamino groups). And N-monohydroxyalkylamino groups such as a hydroxyethylamino group (N-monohydroxy C _1-4 alkylamino group and the like).

The alkylene group A includes a linear or branched alkylene group. Examples of the linear alkylene group include C _2-6 alkylene groups such as ethylene group, trimethylene group and tetramethylene group (preferably straight chain groups). A linear C _2-3 alkylene group, more preferably a linear C _2-3 alkylene group, particularly an ethylene group). Examples of the branched alkylene group include a propylene group, a 1,2-butanediyl group, Examples thereof include branched C _3-6 alkylene groups such as 1,3-butanediyl groups (preferably branched C _3-4 alkylene groups, particularly propylene groups).

M1 representing the number of repeating oxyalkylene groups (OA) (average number of added moles) can be selected from 0 or an integer of 1 or more (eg, 0 to 15, preferably about 0 to 10), for example, 0 to 8 ( For example, it may be 1 to 8), preferably 0 to 5 (eg 1 to 5), more preferably 0 to 4 (eg 1 to 4), particularly 0 to 3 (eg 1 to 3), and usually 0 It may be ˜2 (eg 0 or 1). In addition, when m1 is 2 or more, the type of the alkylene group A may be the same or different. Further, the type of alkylene group A may be the same or different in the same or different ring Z.

In the group — (CH ₂ ) _m2 —COOR ³ , the alkyl group represented by R ³ is a linear or branched chain such as methyl, ethyl, propyl, isopropyl, butyl, or t-butyl. Illustrative examples are C _1-6 alkyl groups. Preferred alkyl groups are C _1-4 alkyl groups, especially C _1-2 alkyl groups. M2 indicating the number of repeating methylene groups (average number of moles added) may be 0 or an integer of 1 or more (eg, 1 to 6, preferably 1 to 4, more preferably about 1 to 2). m2 may usually be 0 or 1 to 2.

Of these, the group X ¹ is preferably a group — [(OA) _m1 —Y ¹ ] (wherein A is an alkylene group, Y ¹ is a hydroxyl group or a glycidyloxy group, and m1 is an integer of 0 or more). , A group in which Y ¹ is a glycidyloxy group — [(OA) _m1 —Y ¹ ] [wherein A represents a C _2-6 alkylene group such as an ethylene group (eg, a C _2-4 alkylene group, particularly a C _2-3 An alkylene group), m1 is an integer of 0 to 5 (for example, 0 or 1)].

In the formula (1), n indicating the number of the group X ¹ substituted on the ring Z is 1 or more, preferably 1 to 3, more preferably 1 or 2 (particularly 1). The number of substitutions n may be the same or different in each ring Z.

The group X ¹ can be substituted at an appropriate position of the ring Z. For example, when the ring Z is a benzene ring, it is substituted at the 2, 3, 4 position (particularly the 3 position and / or the 4 position) of the phenyl group. In many cases, when ring Z is a naphthalene ring, it is often substituted at any one of positions 5 to 8 of the naphthyl group. For example, 1 of the naphthalene ring is substituted with respect to the 9-position of fluorene. Position or 2-position is substituted (substituted by the relationship of 1-naphthyl or 2-naphthyl), and the relationship such as the 1,5-position, 2,6-position, etc. with respect to this substitution position (especially when n is 1, In many cases, the group X ¹ is substituted in the (2,6-position relationship). Moreover, when n is 2 or more, the substitution position is not particularly limited. Further, in the ring assembly arene ring Z, the substitution position of the group X ¹ is not particularly limited, and for example, the arene ring bonded to the 9th position of fluorene and / or the arene ring adjacent to the arene ring may be substituted. Good. For example, the 3-position or 4-position of the biphenyl ring Z may be bonded to the 9-position of fluorene, and when the 3-position of the biphenyl ring Z is bonded to the 9-position of fluorene, the substitution position of the group X ¹ is Any of 2, 4, 5, 6, 2 ′, 3 ′, and 4 ′ positions may be used, and the 6-position may be preferably substituted.

In the formula (1), examples of the substituent R ² include a halogen atom (eg, fluorine atom, chlorine atom, bromine atom, iodine atom), alkyl group (methyl group, ethyl group, propyl group, isopropyl group, butyl group, linear or branched C _1-10 alkyl group such as s-butyl group or t-butyl group, preferably linear or branched C _1-6 alkyl group, more preferably linear or branched chain C _1-4 alkyl group), cycloalkyl group (C _5-10 cycloalkyl group such as cyclopentyl group, cyclohexyl group, etc.), aryl group [phenyl group, alkylphenyl group (methylphenyl (tolyl) group, dimethylphenyl (xylyl), etc. group), a biphenyl group, a _{C 6-12} aryl group such as a naphthyl group, an aralkyl group (benzyl group, phenethyl _{C 6-10} an aryl _{-C 1-4} alkyl group) such as an alkoxy group (e.g., methoxy group, an ethoxy group, a propoxy group, n- butoxy group, isobutoxy group, a linear or branched, such as t- butoxy A chain C _1-10 alkoxy group), a cycloalkoxy group (eg, C _5-10 cycloalkyloxy group such as cyclohexyloxy group), an aryloxy group (eg, C _6-10 aryloxy such as phenoxy group) Group), aralkyloxy group (eg C _6-10 aryl-C _1-4 alkyloxy group such as benzyloxy group), alkylthio group (eg methylthio group, ethylthio group, propylthio group, n-butylthio group, a C _1-10 alkylthio group such as a t-butylthio group), a cycloalkylthio group (for example, C _5-10 cycloalkylthio group such as cyclohexylthio group), arylthio group (eg C _6-10 arylthio group such as thiophenoxy group), aralkylthio group (eg C _6-10 aryl such as benzylthio group) -C _1-4 alkylthio group), acyl group (for example, C _1-6 acyl group such as acetyl group), nitro group, cyano group and the like.

Of these substituents R ² , typically, a halogen atom, a hydrocarbon group (alkyl group, cycloalkyl group, aryl group, aralkyl group), alkoxy group, acyl group, nitro group, cyano group, substituted amino group Etc. Preferable substituent R ² is an alkoxy group (such as a linear or branched C _1-4 alkoxy group such as a methoxy group), particularly an alkyl group (particularly a linear or branched chain C such as a methyl group). _1-4 alkyl group) is preferred. In addition, when the substituent R ² is an aryl group, the substituent R ² may form the ring assembly arene ring together with the ring Z. The type of the substituent R ² may be the same or different in the same or different ring Z.

The number p of the substituent R ² can be appropriately selected depending on the kind of the ring Z and the like, and may be an integer of about 0 to 8, for example, an integer of 0 to 4, preferably 0 to 3 (eg, 0 to 2). ), More preferably 0 or 1. In particular, when p is 1, the ring Z may be a benzene ring, a naphthalene ring or a biphenyl ring, and the substituent R ² may be a methyl group.

Examples of the substituent R ¹ include a cyano group, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, etc.), a carboxyl group, an alkoxycarbonyl group (eg, a C _1-4 alkoxy-carbonyl group such as a methoxycarbonyl group), an alkyl, etc. Groups (eg, C _1-6 alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, and t-butyl groups), aryl groups (eg, C _6-10 aryl groups such as phenyl), etc. Is mentioned.

Among these substituents R ¹ , a linear or branched C _1-4 alkyl group (particularly a C _1-3 alkyl group such as a methyl group), a carboxyl group or a C _1-2 alkoxy-carbonyl group, cyano A group and a halogen atom are preferred. The substitution number k is an integer of 0 to 4 (for example, 0 to 3), preferably an integer of 0 to 2 (for example, 0 or 1), particularly 0. The number of substitutions k may be the same or different from each other. When k is 2 or more, the types of the substituents R ¹ may be the same or different from each other, and are substituted with two benzene rings of the fluorene ring. The type of substituent R ¹ may be the same or different. Further, the substitution position of the substituent R ¹ is not particularly limited, and may be, for example, the 2nd to 7th positions (such as the 2nd, 3rd and / or 7th positions) of the fluorene ring.

Among these, as a preferable fluorene compound, when the group X ¹ is a group — [(OA) _m1 —Y ¹ ] (wherein Y ¹ represents a hydroxyl group), for example, 9,9-bis ( 9,9-bis (hydroxy C _6- ) such as 4-hydroxyphenyl) fluorene, 9,9-bis (6-hydroxy-2-naphthyl) fluorene, 9,9-bis (5-hydroxy-1-naphthyl) fluorene ₁₂ aryl) fluorene; 9,9-bis (di or trihydroxy C _6-12 aryl) fluorene such as 9,9-bis (3,4-dihydroxyphenyl) fluorene; 9,9-bis (3-methyl-4 - 9,9-bis such hydroxyphenyl) fluorene _{(C 1-4} alkyl - hydroxy _{C 6-12} aryl) fluorene; 9,9-bis (3-phenyl-4 Hydroxyphenyl) fluorene, 9,9-bis (4-phenyl-3-hydroxyphenyl) fluorene such as 9,9-bis _{(C 6-12} aryl - hydroxy _{C 6-12} aryl) fluorene; 9,9-bis [ 4- (2-hydroxyethoxy) phenyl] fluorene, 9,9-bis [6- (2-hydroxyethoxy) -2-naphthyl] fluorene, 9,9-bis [5- (2-hydroxyethoxy) -1- 9,9-bis (hydroxy (poly) C _2-4alkoxy- C _6-12 aryl) fluorene such as naphthyl] fluorene; 9,9-bis [3-methyl-4- (2-hydroxyethoxy) phenyl] fluorene 9,9-bis such _{(C 1-4} alkyl - hydroxy _{(poly) C 2-4} alkoxy _{-C 6-12} aryl) fluorene; 9 9- bis [3-phenyl-4- (2-hydroxyethoxy) phenyl] fluorene, 9,9-bis [4-phenyl-3- (2-hydroxyethoxy) phenyl] fluorene such as 9,9-bis (C _6-12 aryl-hydroxy (poly) C _2-4 alkoxy-C _6-12 aryl) fluorene and the like.

Preferred fluorene compounds when the group X ¹ is a group — [(OA) _m1 —Y ¹ ] (wherein Y ¹ represents a glycidyloxy group) include 9,9-bis (glycidyloxyaryl) fluorene For example, 9,9-bis (3-glycidyloxyphenyl) fluorene, 9,9-bis (4-glycidyloxyphenyl) fluorene, 9,9-bis (5-glycidyloxy-1-naphthyl) fluorene, 9,9-bis (glycidyloxy C _6-10 aryl) fluorene such as 9-bis (6-glycidyloxy-2-naphthyl) fluorene; 9,9-bis (glycidyloxy (poly) alkoxyaryl) fluorene, for example 9,9-bis (4- (2-glycidyloxyethoxy) phenyl) fluorene, 9,9-bis (4- (2-glycidyl) Diloxypropoxy) phenyl) fluorene, 9,9-bis (5- (2-glycidyloxyethoxy) -1-naphthyl) fluorene, 9,9-bis (6- (2-glycidyloxyethoxy) -2-naphthyl) 9,9-bis (glycidyloxy (poly) C _2-4 alkoxy C _6-10 aryl) fluorene such as fluorene; 9,9-bis (alkyl-glycidyloxyaryl) fluorene, such as 9,9-bis (3 9,9-bis (C _1-4 alkyl-glycidyloxy C _6-10 aryl) fluorene such as -methyl-4-glycidyloxyphenyl) fluorene; 9,9-bis (alkyl-glycidyloxy (poly) alkoxyaryl) Fluorene, for example 9,9-bis (3-methyl-4- (2-glycidyloxyethoxy) Phenyl) fluorene such as 9,9-bis _{(C 1-4} alkyl - glycidyloxy _{(poly) C 2-4} alkoxy _{C 6-10} aryl) fluorene; 9,9-bis (aryl - glycidyloxy aryl) fluorene, e.g. , 9,9-bis (3-phenyl-4-glycidyl oxyphenyl) fluorene such as 9,9-bis _{(C 6-10} aryl - glycidyloxy _{C 6-10} aryl) fluorene; 9,9-bis (aryl - Glycidyloxy (poly) alkoxyaryl) fluorene, for example, 9,9-bis (C _6-10 aryl-glycidyloxy, such as 9,9-bis (3-phenyl-4- (2-glycidyloxyethoxy) phenyl) fluorene _{(poly) C 2-4} alkoxy _{C 6-10} aryl) fluorene; 9,9-bis (di Glycidyloxy) aryl) fluorene, e.g., 9,9-bis (3,4-di (glycidyloxy) phenyl) fluorene such as 9,9-bis (di _{(glycidyloxy) C 6-10} aryl) fluorene; 9, 9,9-bis (di- (9-bis (di (glycidyloxy (poly) alkoxy) aryl) fluorene), for example, 9,9-bis (3,4-di (2-glycidyloxyethoxy)) phenyl) fluorene (Glycidyloxy (poly) C _2-4 alkoxy) C _6-10 aryl) fluorene and the like can be exemplified.

These fluorene compounds (B1) can be used alone or in combination of two or more. Note that “(poly) alkoxy” is used to mean both an alkoxy group and a polyalkoxy group.

(Cellulose nanofiber)
Cellulose nanofibers (or cellulose nanofibers) constituting the modified cellulose nanofiber (B) are cellulose fibers obtained by refining cellulose (cellulose raw material) to the nano order (or microfibrillation), and microorganism-derived nanometer-sized cellulose. Fiber. Examples of the cellulose nanofiber include pulps having a low content of non-cellulosic components such as lignin and hemicellulose, for example, plant-derived cellulose raw materials {for example, wood [for example, conifers (pine, fir, spruce, tsuga, cedar, etc.), Hardwood (beech, hippopotamus, poplar, maple, etc.)], herbaceous plants [hemp (hemp, flax, manila hemp, ramie, etc.), straw, bagasse, mitsumata, etc., seed hair fibers (cotton linter, Bombax cotton, capok Etc.), bamboo, sugarcane, etc.}, pulps produced from animal-derived cellulose raw materials (eg, squirt cellulose), bacterial-derived cellulose raw materials (eg, cellulose contained in Nata de Coco), and the like. These cellulose nanofibers can be used alone or in combination of two or more. Among these cellulose nanofibers, wood nanofibers derived from wood pulp (for example, softwood pulp, hardwood pulp, etc.), pulp derived from seed hair fibers (for example, cotton linter pulp), and the like are preferable. The pulp may be a mechanical pulp obtained by mechanically treating a pulp material, but a chemical pulp obtained by chemically treating a pulp material is preferable because the content of non-cellulosic components is small.

The average fiber diameter and average fiber length of the cellulose nanofibers (or raw material cellulose nanofibers) can be selected so that the average fiber diameter and average fiber length of the modified cellulose nanofibers are within the ranges described below. The average fiber diameter, the average fiber length, and the ratio of the average fiber length to the average fiber diameter (aspect ratio) of the cellulose nanofibers may be the same as the range of the modified cellulose nanofibers described later, and are generally substantially the same.

The cellulose nanofiber may be cellulose (or cellulose fiber) having high crystallinity, and the crystallinity of cellulose is, for example, 40 to 100% (for example, 50 to 100%), preferably 60 to 100%, more preferably May be about 70 to 100% (especially 75 to 100%), and usually the crystallinity may be 60% or more (for example, 60 to 99%). Examples of the crystal structure of cellulose include I-type, II-type, III-type, and IV-type, and an I-type crystal structure excellent in linear expansion characteristics and elastic modulus is preferable.

(Modified cellulose nanofiber (B) and production method thereof)
The modified cellulose nanofiber (or modified cellulose nanofiber) (B) is a cellulose derivative in which the cellulose nanofiber and the fluorene compound (B1) are bonded.

The form of chemical modification (or bonding) of the modified cellulose nanofiber (B) is not particularly limited. For example, when the fluorene compound (B1) is a fluorene compound represented by the formula (1), the fluorene compound (B1) The reactive group (heteroatom-containing functional group) can be appropriately selected. Specifically, in the formula (1), when Y ¹ is a hydroxyl group, an ether of the hydroxyl group and / or carboxyl group of cellulose nanofiber and the hydroxyl group of the fluorene compound represented by the formula (1) It may be a bond and / or an ester bond, and when Y ¹ is a glycidyloxy group, the hydroxyl group and / or carboxyl group of the cellulose nanofiber and the glycidyl group of the fluorene compound represented by the formula (1) It may be an ether bond and / or an ester bond. In addition, the carboxyl group of a cellulose nanofiber may be formed in the manufacture processes, such as a pulp.

The modified cellulose nanofiber (B) may be produced by reacting the raw cellulose nanofiber and the fluorene compound (B1) in the presence of a predetermined catalyst. In the rubber component (A), the raw cellulose nanofiber And the fluorene compound (B1) may be produced by reacting in the process of kneading.

The ratio of the raw material cellulose nanofiber can be selected according to the reactive group of the fluorene compound (B1). For example, it is 0.1 to 500 parts by weight (for example, 1 to 300 parts by weight with respect to 100 parts by weight of the fluorene compound (B1)). Part by weight), and may be, for example, about 5 to 200 parts by weight (particularly 10 to 150 parts by weight).

When a catalyst is used, the catalyst can also be selected according to the reactive group of the fluorene compound. When the reactive group is a hydroxyl group, an acid catalyst may be used. Examples of the acid catalyst include Bronsted acids, for example, inorganic acids such as sulfuric acid, hydrochloric acid, and phosphoric acid, organic acids such as p-toluenesulfonic acid, and solid acids [for example, heteropolyacids (tungsten heteropolyacid, molybdenum heteropolyacid, etc. ), Cation exchange resins (strong acid cation exchange resins having sulfonic acid groups, fluorine-containing cation exchange resins having sulfonic acid groups, weak acid cation exchange resins having carboxylic acid groups, etc.)]. These acid catalysts can be used alone or in combination of two or more.

When the reactive group is a glycidyl group, a base catalyst may be used. The base catalyst may be either an inorganic base or an organic base. Examples of the inorganic base include alkali metal hydroxides (such as sodium hydroxide and potassium hydroxide) and alkali metal carbonates. Examples of the organic base include tertiary amines such as trialkylamine (such as trimethylamine and triethylamine), alkanolamine (such as triethanolamine and dimethylaminoethanol), heterocyclic amine (such as N-methylmorpholine), and hexamethylenetetramine. , Diazabicycloundecene (DBU), diazabicyclononene (DBN), 1,4-diazabicyclo [2.2.2] octane (DABCO), and the like. These base catalysts can also be used alone or in combination of two or more.

The amount of the catalyst used can be selected according to the type of the catalyst, but can be appropriately selected from a range of, for example, about 0.01 to 100 parts by weight with respect to 100 parts by weight of the raw material cellulose nanofiber, and usually 0.01 to 20 parts. Parts by weight (eg 0.1 to 18 parts by weight), preferably 0.5 to 18 parts by weight (eg 1 to 17 parts by weight), more preferably about 3 to 15 parts by weight (especially 5 to 15 parts by weight). May be.

When using a catalyst, the reaction may be carried out in the absence of an organic solvent, but is usually carried out in the presence of an organic solvent. The organic solvent may be impregnated in the raw material cellulose nanofibers, but is often reacted in a dispersion system in which the raw material cellulose nanofibers are dispersed in the organic solvent. When the raw material cellulose nanofibers and the fluorene compound (B1) are reacted in a dispersion system in which the raw material cellulose nanofibers are dispersed in an organic solvent, they can be reacted uniformly. The modified cellulose nanofiber (B) obtained by such a method has high handleability and dispersibility.

When drying raw material cellulose nanofibers (particularly, microfibrillated fibers, nanofibers having an average fiber diameter of nanometer size), the fibers may become entangled and cannot be redispersed. Therefore, usually, raw material cellulose nanofibers are often marketed as water-impregnated or aqueous dispersions. In such an aqueous dispersion, a conventional solvent replacement method for replacing the water of the aqueous dispersion with an organic solvent, for example, adding a water-soluble solvent to the aqueous dispersion of raw material cellulose nanofibers, and separating the raw material cellulose nanofibers After removing the solvent (or removing the solvent), a dispersion liquid in which the raw material cellulose nanofibers are dispersed in the organic solvent can be prepared by a method of repeating the operation of adding and mixing the organic solvent. When a water-soluble organic solvent having a boiling point higher than that of water is used, the solvent can be replaced by removing water by distillation (including azeotropic distillation).

Examples of the water-soluble organic solvent include alcohols (C _1-4 alkanols such as methanol, ethanol, propanol and isopropanol), ethers (cyclic ethers such as dioxane and tetrahydrofuran), ketones (acetone and the like), amides, and the like. (Dimethylformamide, diethylformamide, dimethylacetamide, diethylacetamide, etc.), sulfoxides (dimethylsulfoxide, etc.), alkanediols (eg C _2-4 alkanediols such as ethylene glycol, propylene glycol), cellosolves (methyl cellosolve, Ethyl cellosolve, etc.), carbitols (ethylcarbitol, etc.), carbonates (ethylene carbonate, propylene carbonate, dimethyl carbonate, etc.), etc. And the like. These solvents may be used alone or in combination of two or more.

In the cellulose-containing dispersion obtained by solvent substitution using a water-soluble organic solvent, the water-soluble organic solvent can be replaced with a water-insoluble organic solvent in the same manner as described above. Water-insoluble organic solvents include ethers (dialkyl ethers such as diethyl ether and diisopropyl ether), esters (methyl acetate, ethyl acetate, butyl acetate, etc.), ketones (methyl ethyl ketone, methyl isobutyl ketone, etc.), nitriles (Eg benzonitrile), cellosolve acetates, carbitol acetates, hydrocarbons (aliphatic hydrocarbons such as hexane, octane, cyclohexane, aromatic hydrocarbons such as toluene), halogenated hydrocarbons (dichloromethane, Chloroform, carbon tetrachloride, dichloroethane, trichloroethylene, etc.). These water-insoluble organic solvents can also be used alone or in combination of two or more.

Of these organic solvents, aprotic solvents, particularly aprotic polar solvents (for example, ethers, ketones, amides, sulfoxides, etc.) are preferable.

The solubility parameter (SP value, (cal / cm) ² ) of an organic solvent (eg, aprotic polar solvent) may be about 8 to 15 (eg, 8.5 to 15), usually 9 to 14.5. It may be about (for example, 10 to 14.5).

The solid content concentration of the raw material cellulose nanofibers in the dispersion is, for example, 0.01 to 30% by weight (eg 0.1 to 20% by weight), preferably 1 to 15% by weight, more preferably 3 to 12% by weight ( For example, it may be about 5 to 10% by weight. If the solid content concentration is too low, the reaction efficiency may decrease.

When a catalyst is used, the reaction may be performed under reduced pressure, but is usually performed under pressure or normal pressure in many cases. The reaction temperature can be appropriately selected depending on the boiling point of the solvent, and may be, for example, about 50 to 200 ° C. (eg 70 to 170 ° C.), preferably about 80 to 150 ° C. (eg 100 to 130 ° C.). The reaction may be performed under reflux of the solvent. The reaction time is not particularly limited and is, for example, about 10 minutes to 48 hours (for example, 30 minutes to 24 hours). Furthermore, the reaction can be performed with stirring in air or in an atmosphere of an inert gas (such as a rare gas such as nitrogen or argon).

The reaction may be carried out while stirring the reaction system. As raw material cellulose fibers, cellulose or fibers other than nanometer size (for example, fibers having an average fiber diameter of micrometer size, pulp fibers, etc.) are used. Alternatively, modified cellulose nanofibers obtained by refining cellulose may be obtained by applying mechanical shearing force to the fibers. Further, the modified cellulose fiber may be refined by defibrating after the reaction is completed.

The modified cellulose nanofiber (B) produced by the reaction using a catalyst may be separated and purified by a conventional method (for example, centrifugation, filtration, concentration, extraction, etc.). For example, a solvent capable of dissolving at least the fluorene compound (B1) is added to the reaction mixture, the unreacted fluorene compound is removed by a separation method (conventional method) such as centrifugation, filtration, and extraction, followed by separation and purification. Also good. The separation operation can be performed a plurality of times (for example, about 2 to 5 times). Furthermore, the modified cellulose fiber having a powdery form can be obtained by drying the separated and purified modified cellulose under heating, reduced pressure, or normal pressure.

In addition, when the modified cellulose obtained by repeatedly removing the unreacted fluorene compound by the separation method or the like is analyzed by a method such as Raman analysis, there are a peak derived from the cellulose and a peak derived from the fluorene compound. It can be confirmed that the fluorene compound is bonded.

On the other hand, when the modified cellulose nanofiber is produced by kneading in the unvulcanized rubber component, the modified cellulose nanofiber is obtained during the production process of the vulcanized rubber composition, as will be described later.

(Characteristics of modified cellulose nanofiber (B))
The modified cellulose nanofiber (B) obtained using the catalyst usually has a powdery form and is excellent in handleability. Moreover, even if the modification ratio (bonding amount) of the fluorene compound (B1) is relatively small, the modified cellulose nanofiber (B) may have a powdery form.

The ratio (modification rate) of the fluorene compound (B1) bound to the cellulose nanofibers is in the range of about 0.01 to 33% by weight (for example, 1 to 25% by weight) with respect to the total amount of the modified cellulose nanofibers (B). You can choose. In particular, when the group X ^{1 of} the fluorene compound (B1) is a group — [(OA) _m1 —Y ¹ ] (wherein Y ¹ represents a hydroxyl group), the modification rate is the modified cellulose nanofiber (B ) In the range of about 0.01 to 30% by weight, for example 0.1 to 30% by weight, preferably 0.5 to 25% by weight (eg 1 to 25% by weight), more preferably It may be about 2 to 20% by weight (particularly 3 to 20% by weight). When the group X ^{1 of} the fluorene compound (B1) is a group — [(OA) _m1 —Y ¹ ] (wherein Y ¹ represents a glycidyloxy group), the modification rate is 0.01 to 33 wt. % (Eg 0.1 to 30% by weight), preferably 1 to 25% by weight (eg 2 to 25% by weight), more preferably 3 to 20% by weight (especially 5 to 20% by weight). Good.

If the modification rate is too large, properties such as dispersibility in an aqueous solvent and a low linear thermal expansion coefficient may be deteriorated. On the other hand, if the modification rate is too small, a powdery form cannot be formed, and handling properties are likely to be deteriorated. Or dispersibility (or miscibility) with the rubber component in the rubber composition may be reduced. The modification rate can be measured by the method described in Examples described later.

The average fiber diameter of the modified cellulose nanofiber (B) is, for example, about 1 to 1000 nm (eg 3 to 800 nm), preferably 4 to 500 nm (eg 5 to 300 nm), more preferably about 10 to 200 nm (especially 15 to 100 nm). There may be. If the average fiber diameter is too large, properties such as strength of the rubber composition may be deteriorated. The maximum fiber diameter of the cellulose nanofiber is, for example, about 3 to 1000 nm (for example, 4 to 900 nm), preferably about 5 to 700 nm (for example, 10 to 500 nm), more preferably about 15 to 400 nm (especially 20 to 300 nm). Also good. In many cases, the cellulose nanofibers substantially do not contain cellulose fibers having a fiber diameter of micrometer size.

The average fiber length of the modified cellulose nanofiber (B) can be selected, for example, in the range of about 0.01 to 500 μm (for example, 0.1 to 400 μm), and is usually 1 μm or more (for example, 5 to 300 μm), preferably 10 μm or more (for example, 20 to 200 μm), more preferably 30 μm or more (particularly 50 to 150 μm). If the average fiber length is too short, the mechanical properties of the rubber composition may be reduced. Conversely, if the average fiber length is too long, the dispersibility in the rubber composition may be reduced.

The ratio (aspect ratio) of the average fiber length to the average fiber diameter of the modified cellulose nanofiber (B) is, for example, 5 or more (for example, about 5 to 10,000), preferably 10 or more (for example, about 10 to 5000), and more preferably 20 (For example, about 20 to 3000), particularly 50 or more (for example, about 50 to 2000), 100 or more (for example, about 100 to 1000), and even 200 or more (for example, about 200 to 800). Good. Further, if the aspect ratio is too small, the reinforcing effect on the rubber component is lowered, and if the aspect ratio is too large, uniform dispersion becomes difficult and the fibers may be easily decomposed (or damaged).

In the present specification and claims, the average fiber diameter, average fiber length, and aspect ratio of the modified cellulose nanofiber (B) (or raw material cellulose nanofiber) are randomly determined from an image of a scanning electron micrograph. It may be calculated by selecting individual fibers and averaging them.

The modified cellulose nanofiber (B) has a low water content because the hydrophobicity is improved by the modification of the fluorene compound (B1). That is, the moisture content is 0 to 7% by weight (for example, 0 to 5% by weight), preferably 0.1 to 5% by weight, and more preferably when left standing for one day and night under the conditions of a temperature of 25 ° C. and a humidity of 60%. May be about 0.3 to 3% by weight. The water content can be measured using a near infrared analyzer or the like.

When the bulk density (apparent density) of the modified cellulose nanofiber (B) is measured in accordance with JIS K7365-1999 under the conditions of a temperature of 25 ° C. and a humidity of 60%, for example, 0.01 to 0.7 g / ml, preferably 0.05 to 0.5 g / ml, more preferably about 0.1 to 0.3 g / ml. The bulk density P can be calculated from the formula P = W / V by measuring the volume V of a modified cellulose nanofiber having a predetermined weight W in a measuring cylinder.

The modified cellulose nanofiber (B) has a high fluidity and an angle of repose measured according to JIS R9301-2-2 under conditions of a temperature of 25 ° C. and a humidity of 60%, for example, 20 to 45 °, The angle may be preferably 25 to 40 °, more preferably about 30 to 35 °. If the fluidity is too large, the handleability is lowered. Conversely, if the fluidity is too small, the dispersibility may be lowered.

The modified cellulose nanofiber (B) maintains the nanofiber form without forming a viscous liquid. Therefore, the molecular weight (or degree of polymerization) is relatively large, and the viscosity average degree of polymerization may be, for example, about 100 to 10,000, preferably about 200 to 5,000, more preferably about 300 to 2,000.

Viscosity average degree of polymerization can be measured by the viscosity method described in TAPPI T230. That is, 0.04 g of modified cellulose nanofiber (or raw material cellulose nanofiber) is precisely weighed, 10 mL of water and 10 mL of 1M copper ethylenediamine aqueous solution are added, and the modified cellulose is dissolved by stirring for about 5 minutes. The obtained solution is put into an Ubbelohde type viscosity tube, and the flow rate is measured at 25 ° C. A mixed liquid of 10 mL of water and 10 mL of 1M copper ethylenediamine aqueous solution is measured as a blank. Using the intrinsic viscosity [η] calculated based on these measured values, the viscosity average degree of polymerization can be calculated according to the following formula described in the Wood Science Experiment Manual (edited by the Wood Society of Japan, Bunnendo Publishing).

Viscosity average polymerization degree = 175 × [η]

Further, in the vulcanized rubber composition of the present invention, when the properties of the modified cellulose nanofiber (B) (for example, low linear thermal expansion properties, strength, heat resistance, etc.) are effectively expressed, the modified cellulose nanofiber with high crystallinity Fiber is preferred. As described above, the modified cellulose can maintain the crystallinity of the cellulose nanofibers, and therefore the crystallinity of the modified cellulose nanofiber (B) can directly refer to the value of the cellulose nanofibers. For example, the crystallinity of the modified cellulose is 40 to 100% (eg 50 to 100%), preferably 60 to 100% (eg 65 to 100%), more preferably 70 to 100% (particularly 75 to 100%). Usually, the degree of crystallinity may be 60% or more (for example, about 75 to 99%). If the degree of crystallinity is too small, characteristics such as linear thermal expansion characteristics and strength may be deteriorated. Examples of the crystal structure of cellulose include I-type, II-type, III-type, and IV-type, and an I-type crystal structure having high low linear expansion characteristics and high elastic modulus is preferable. The crystallinity can be measured using a powder X-ray diffractometer (“Ultima IV” manufactured by Rigaku Corporation).

The proportion of the modified cellulose nanofiber (B) can be selected from the range of about 0.1 to 30 parts by weight, for example, 0.2 to 25 parts by weight, preferably 0.3, based on 100 parts by weight of the rubber component (A). The amount is about 20 to 20 parts by weight, more preferably about 0.5 to 15 parts by weight (particularly 1 to 10 parts by weight). Furthermore, in this invention, even if there is little ratio of a modified cellulose nanofiber (B), a mechanical characteristic, heat resistance, etc. can be improved, and the ratio of a modified cellulose nanofiber (B) is 100 weight part of rubber components (A). On the other hand, it may be, for example, about 0.1 to 10 parts by weight, preferably about 0.3 to 7 parts by weight, more preferably about 0.5 to 5 parts by weight (particularly about 1 to 3 parts by weight). If the proportion of the modified cellulose nanofiber (B) is too small, the mechanical properties of the rubber composition may be reduced, and conversely if too high, the moldability of the rubber composition may be reduced.

In the present invention, the mechanical properties of the rubber composition can be improved by adding the modified cellulose nanofiber (B) in the above ratio to the rubber component (A). Furthermore, the heat resistance of a vulcanized rubber composition can be improved by adding unmodified cellulose nanofibers, which are raw materials for the modified cellulose nanofibers (B), to the rubber component (A). The ratio of the cellulose nanofibers can also be selected from the same range as the amount of the modified cellulose nanofibers (B) added (the ratio in the composition). The modified cellulose nanofiber (B) is preferable to the unmodified cellulose nanofiber from the viewpoint that the mechanical properties of the vulcanized rubber composition can be greatly improved.

[Reinforcing agent (C)]
The vulcanized rubber composition of the present invention further includes a reinforcing agent (C) in addition to the rubber component (A) and the modified cellulose nanofiber (B) in order to improve mechanical properties such as hardness and strength. May be.

As the reinforcing agent (C), a conventional reinforcing agent can be used. For example, granular reinforcing agents (carbonaceous materials such as carbon black and graphite; calcium oxide, magnesium oxide, barium oxide, iron oxide, copper oxide, titanium oxide, Metal oxides such as aluminum oxide (alumina); metal silicates such as calcium silicate and aluminum silicate; metal carbides such as silicon carbide and tungsten carbide; metal nitrides such as titanium nitride, aluminum nitride and boron nitride; carbonic acid Metal carbonates such as magnesium and calcium carbonate; metal sulfates such as calcium sulfate and barium sulfate; zeolite, diatomaceous earth, calcined diatomaceous earth, activated clay, silica, talc, mica, kaolin, sericite, bentonite, montmorillonite, smectite, Mineral materials such as clay)維状 reinforcing agents (glass fibers, carbon fibers, boron fibers, whiskers, inorganic fibers such as wollastonite; polyester fibers, polyamide fibers, and organic fibers such as cellulose fibers) and the like. These reinforcing agents can be used alone or in combination of two or more.

Of the reinforcing agents, the cellulose fiber may be a cellulose nanofiber. Furthermore, when cellulose nanofibers are produced by reacting raw material cellulose nanofibers and fluorene compound (B1) in the course of kneading to produce modified cellulose nanofibers, cellulose nanofibers remaining without reacting with fluorene compound (B1) It may be a fiber.

Among these reinforcing agents, granular reinforcing agents (particularly granular inorganic reinforcing agents) such as carbon black, calcium carbonate, and silica are widely used, and in combination with the modified cellulose nanofiber (B), the mechanical properties of the rubber composition are improved. Carbon black, calcium carbonate, and silica are preferable, and carbon black is particularly preferable because it can be greatly improved. In the present invention, the modified cellulose nanofiber (B) not only has its own dispersibility in the rubber component, but also has a high compatibility with a granular reinforcing agent (particularly, a granular inorganic reinforcing agent such as carbon black). The dispersibility of can also be improved.

Examples of carbon black include acetylene black, lamp black, thermal black, furnace black, channel black, ketjen black, coated carbon black, and graft carbon black. These carbon blacks can be used alone or in combination of two or more.

The calcium carbonate may be calcium carbonate surface-treated with a surface treatment agent such as rosin acid.

Examples of silica include dry method white carbon, wet method white carbon, colloidal silica, and precipitated silica. These silicas can be used alone or in combination of two or more.

The shape of the granular inorganic reinforcing agent is not particularly limited, and is spherical, elliptical, polyhedral [for example, cubic, rectangular parallelepiped, tetrahedral (pyramid), etc.], flat (plate, scale or flake) ), Layer shape, rod shape, needle shape, indeterminate shape, and the like. The granular inorganic reinforcing agent may be in a porous shape. Of these, isotropic shapes such as a substantially spherical shape are preferred.

The average particle size (number average primary particle size) of the granular inorganic reinforcing agent is, for example, about 1 to 1000 nm, preferably 3 to 300 nm, more preferably 5 to 100 nm (particularly 10 to 50 nm). If the particle size of the granular inorganic reinforcing agent is too large, the mechanical properties of the vulcanized rubber composition may be reduced, and if it is too small, it may be difficult to uniformly disperse.

The average particle size (number average primary particle size) of carbon black can be selected from the range of about 5 to 200 nm, for example, 10 to 150 nm, preferably 15 to 100 nm, more preferably 20 to 80 nm (particularly 30 to 50 nm). . If the average particle size of the carbon black is too small, uniform dispersion may be difficult, and if it is too large, the mechanical properties of the rubber composition may be deteriorated.

In addition, in this specification and a claim, the average particle diameter of a granular inorganic reinforcing agent can be measured based on a conventional method, for example, a scanning electron microscope (SEM) or a transmission electron microscope (TEM) photograph.

The proportion of the reinforcing agent (C) can be selected from the range of about 10 to 300 parts by weight, for example 20 to 200 parts by weight, preferably 30 to 150 parts by weight, more preferably 100 parts by weight of the rubber component (A). About 50 to 100 parts by weight (particularly 60 to 80 parts by weight). If the proportion of the reinforcing agent is too small, the effect of improving the mechanical properties of the vulcanized rubber composition may be reduced. Conversely, if the amount is too large, the elongation or strength of the vulcanized rubber composition may be reduced. is there.

[Processing aid (D)]
The vulcanized rubber composition of the present invention may further contain a processing aid (D) in addition to the rubber component (A) and the modified cellulose nanofiber (B) in order to improve moldability and the like.

The processing aid (D) is not particularly limited as long as it is an additive compatible with the rubber component (A) and can reduce the viscosity of the unvulcanized rubber composition. For example, a solvent (for example, hexane, cyclohexane, etc.) Aliphatic hydrocarbons; aromatic hydrocarbons such as benzene, xylene and toluene; alkanols such as methanol, ethanol and isopropanol; ketones such as acetone, methyl ethyl ketone and cyclohexanone; halogenated hydrocarbons such as chloroform and trichloroethylene; ethyl ether and tetrahydrofuran Ethers such as ethyl acetate; amides such as dimethylformamide; sulfur compounds such as carbon disulfide), softeners (oils such as paraffinic oil, naphthenic oil, process oil), plasticizers (stearin) Acid, steari Acid metal salts, waxes, paraffins, fatty acid amide) and the like. These processing aids can be used alone or in combination of two or more.

Of these processing aids, solvents such as toluene, softeners such as naphthenic oil and process oil, and plasticizers such as stearic acid are widely used.

In the present invention, even when these processing aids are blended in order to improve moldability, the modified cellulose nanofiber (B) is contained, so that the vulcanized rubber composition (particularly EPDM) is added with the processing aid (D). Decrease in mechanical properties of a vulcanized rubber composition containing an olefin rubber such as olefin rubber can be suppressed.

The proportion of the processing aid (D) can be appropriately selected according to the type of the rubber component (A), and can be selected from the range of about 0.1 to 500 parts by weight with respect to 100 parts by weight of the rubber component (A). The amount is 0.5 to 400 parts by weight (for example, 1 to 300 parts by weight), preferably 1 to 200 parts by weight, and more preferably about 3 to 100 parts by weight. When the rubber component (A) is an olefin rubber, the ratio of the processing aid (D) is, for example, 10 to 200 parts by weight, preferably 20 to 150 parts by weight, with respect to 100 parts by weight of the rubber component (A). More preferably, it may be about 30 to 100 parts by weight. If the ratio of the processing aid (D) is too small, the effect of improving the moldability may be reduced, and conversely if too high, the mechanical properties of the vulcanized rubber composition may be reduced.

[Vulcanizing agent (E)]
The vulcanized rubber composition of the present invention usually contains a vulcanizing agent (E). As the vulcanizing agent (E), a conventional vulcanizing agent can be used depending on the type of the rubber component (A). The vulcanizing agent (E) includes a sulfur-based vulcanizing agent and an organic peroxide.

Examples of sulfur vulcanizing agents include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, surface treated sulfur, sulfur chloride (sulfur monochloride, sulfur dichloride, etc.), morpholine disulfide, alkylphenol disulfide. Etc.

Examples of the organic peroxide include diacyl peroxides such as dilauroyl peroxide, dibenzoyl peroxide, and 2,4-dichlorobenzoyl peroxide; di-t-butyl peroxide, t-butylcumyl peroxide, and dicumyl peroxide. Oxide, 1,1-di-butylperoxy-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di (t-butylperoxy) -hexane, 1,3-bis (t- Dialkyl peroxides such as butylperoxy-isopropyl) benzene; hydroperoxides such as t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide; n-butyl-4,4-di-t-butylperoxide Oxyvalerate, 2,5-dimethylhexane-2,5 Such as peroxy esters, such as di (peroxyl benzoate) and the like.

These vulcanizing agents can be used alone or in combination of two or more. Of these, dialkyl peroxides such as sulfur and dicumyl peroxide are widely used.

The proportion of the vulcanizing agent (E) is, for example, 0.1 to 10 parts by weight, preferably 0.5 to 8 parts by weight, and more preferably 0.6 to 5 parts by weight with respect to 100 parts by weight of the rubber component (A). Parts (particularly 0.8 to 3 parts by weight).

[Vulcanization aid (F)]
The vulcanized rubber composition of the present invention may further contain a vulcanization aid (F) in order to accelerate vulcanization. Examples of the vulcanization aid (F) include organic vulcanization accelerators [for example, N-cyclohexyl-2-benzothiazylsulfenamide (CBS), Nt-butyl-2-benzothiazylsulfene. Sulfenamide accelerators such as amide (TBBS); thiuram accelerators such as tetramethylthiuram monosulfide (TMTM) and tetramethylthiuram disulfide (TMTD); 2-mercaptobenzothiazole (MBT), a zinc salt of MBT, Thiazole accelerators such as dibenzothiazyl disulfide (MBTS); thiourea accelerators such as trimethylthiourea (TMU) and diethylthiourea (EDE); guanidines such as diphenylguanidine (DPG) and diortolylguanidine (DOTG) Accelerator: Sodium dimethyldithiocarbamate Any dithiocarbamic acid accelerator; xanthate accelerator such as zinc isopropylxanthate; aldehyde-amine or aldehyde-ammonia accelerator such as hexanemethylenetetramine], aromatic maleimide (N, N′-m- Arene bismaleimide such as phenylene dimaleimide), inorganic auxiliary agents [zinc oxide (zinc white), magnesium oxide, etc.] and the like.

These vulcanization aids can be used alone or in combination of two or more. Of these, sulfenamide accelerators such as CBS, thiuram accelerators such as TMTD, and inorganic assistants such as zinc oxide are widely used.

The ratio of the vulcanization aid (F) is, for example, about 3 to 20 parts by weight, preferably about 4 to 15 parts by weight, and more preferably about 5 to 10 parts by weight with respect to 100 parts by weight of the rubber component (A). Also good. The proportion of the organic vulcanization accelerator is, for example, 0.5 to 5 parts by weight, preferably 1 to 4 parts by weight, and more preferably 1.5 to 3.5 parts by weight with respect to 100 parts by weight of the rubber component (A). It may be about a part. The ratio of the inorganic auxiliary (particularly zinc white) is, for example, about 2 to 10 parts by weight, preferably about 3 to 8 parts by weight, and more preferably about 4 to 6 parts by weight with respect to 100 parts by weight of the rubber component (A). There may be.

[Other additives (G)]
The vulcanized rubber composition of the present invention may contain a conventional additive added to the vulcanized rubber depending on the type of the rubber component (A). Examples of conventional additives include resin components (thermoplastic resins, thermosetting resins, etc.), vulcanization retarders, dispersants, aging or antioxidants (aromatic amine-based, benzimidazole-based anti-aging agents, etc.) , Colorants (for example, dyes and pigments), tackifiers, coupling agents (silane coupling agents, etc.), stabilizers (ultraviolet absorbers, light stabilizers, heat stabilizers, etc.), mold release agents, lubricants, Flame retardants (phosphorous flame retardants, halogen flame retardants, inorganic flame retardants, etc.), flame retardant aids, antistatic agents, conductive agents, flow control agents, leveling agents, antifoaming agents, surface modifiers, low stress Examples include agents, nucleating agents, crystallization accelerators, antibacterial agents, and preservatives.

These other additives can be used alone or in combination of two or more. The ratio of the other additive is, for example, about 0.1 to 50 parts by weight, preferably about 0.5 to 30 parts by weight, and more preferably about 1 to 10 parts by weight with respect to 100 parts by weight of the rubber component (A). May be.

[Method for producing vulcanized rubber composition]
The vulcanized rubber composition of the present invention kneads the rubber component (A), the modified cellulose nanofiber (B) in which the fluorene compound (B1) having an aryl group at the 9th and 9th positions is bonded and / or its raw material. It is obtained through a kneading step and a vulcanization step of vulcanizing the obtained kneaded composition to obtain a vulcanized rubber composition.

In the kneading step, the modified cellulose nanofiber (B) may be the fluorene compound (B1) and the unmodified cellulose nanofiber that are the raw materials. By adding these raw materials, the kneading step and / or vulcanization is performed. The modified cellulose nanofiber (B) is produced by the process.

In the kneading step, a conventional method can be used as a method for kneading the composition containing the rubber component (A) and the modified cellulose nanofiber (B). For example, a mixing roller, a kneader, a Banbury mixer, an extruder (uniaxial or biaxial) A method using a shaft extruder or the like can be used. Of these, a pressure kneader is preferable.

In the kneading step, each component including the rubber component (A) and the modified cellulose nanofiber (B) (or a raw material thereof) may be added in a lump, but the modified cellulose nanofiber (B) and / or the raw material thereof may be added. The dispersion liquid previously dispersed in the processing aid (D) and the rubber component (A) may be kneaded. By preparing the dispersion in advance, the modified cellulose nanofiber (B) can be more uniformly dispersed in the rubber component (A), and the mechanical properties of the vulcanized rubber can be improved. When preparing the dispersion, the processing aid (D) is preferably process oil, organic solvent, plasticizer (including liquid rubber as a plasticizer), and the like. When a solvent having a low boiling point is selected as the processing aid (D), part or all of the solvent is volatilized and does not remain in the vulcanized rubber composition (the components constituting the vulcanized rubber composition) Must not). The solid content concentration in the dispersion is, for example, about 0.1 to 50% by weight, preferably about 0.5 to 30% by weight, and more preferably about 1 to 20% by weight.

Kneading may be performed without heating or under heating. In the case of heating, the kneading temperature is, for example, about 30 to 250 ° C., preferably 40 to 225 ° C., more preferably about 50 to 200 ° C.

In the vulcanization step, the vulcanization temperature can be selected according to the type of the rubber component (A), and is, for example, about 100 to 250 ° C., preferably 150 to 200 ° C., more preferably about 160 to 190 ° C.

The resulting vulcanized rubber composition may have a durometer hardness of 50 or more (particularly 60 or more), but it is 70 or more, preferably 75 or more (for example, about 75 to 90) by using carbon black as a reinforcing agent. ) Can also be adjusted.

In the present specification and claims, the durometer hardness can be measured according to JIS K6253 type A.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. Details of the raw materials and measuring instruments used and the evaluation methods are as follows.

(Raw material)
BPFG: 9,9-bis (4-glycidyloxyphenyl) fluorene SBR: “JSR 1502” manufactured by JSR Corporation
NBR: “JSR N230S” manufactured by JSR Corporation
EPDM1: “JSR EP21” manufactured by JSR Corporation, Mooney viscosity 26
EPDM2: “JSR EP27” manufactured by JSR Corporation, Mooney viscosity 70
CB N234: “Seast 7HM” manufactured by Tokai Carbon Co., Ltd., average primary particle size 19 nm
CB HAF: “Seast 3” manufactured by Tokai Carbon Co., Ltd., average primary particle size 28 nm
CB SRF: “Seast S” manufactured by Tokai Carbon Co., Ltd., average primary particle size 66 nm
Silica: Tosoh Silica Co., Ltd. “Nipsil VN3”
Calcium carbonate: “Synthetic calcium carbonate white luster 0” manufactured by Shiraishi Calcium Co., Ltd.
Process oil: “Vivatec 500 (TDAE)” manufactured by H & R Co., Ltd.
Naphthenic oil: “Diana Process NS-100” manufactured by Idemitsu Kosan Co., Ltd.
Paraffin oil: “Diana Process PW-380” manufactured by Idemitsu Kosan Co., Ltd.
Plasticizer DOP: “Bis (2-ethylhexyl) phthalate” manufactured by Mitsubishi Chemical Corporation
Zinc Hana No.1: Made by Mitsui Mining & Smelting Co., Ltd. Stearic acid: NOF Co., Ltd.
Sulfur: “Powder sulfur” manufactured by Tsurumi Chemical Co., Ltd.
PEG4000: Sanyo Chemical Industries “PEG-4000S”
Accelerator CBS: “Noxeller CZ-G” manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
Accelerator TT: “Noxeller TT-P” manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
Accelerator M: “Noxeller MP” manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
Accelerator CZ: “Noxeller CZ-G” manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
Accelerator Mix No1: "Noxeller Mix No1" manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
Accelerator DPG: “Noxeller D” manufactured by Ouchi Shinsei Chemical Co., Ltd.
Accelerator DM: “Noxeller DM-P” manufactured by Ouchi Shinsei Chemical Co., Ltd.
Accelerator TS: “Noxeller TS” manufactured by Ouchi Shinsei Chemical Co., Ltd.
Pulp: “Pure pulp 5 mm” manufactured by Sanyo Chemical Co., Ltd.

(Modification rate of fluorene compound bonded to modified cellulose nanofiber)
The modification rate of the fluorene compound (hereinafter referred to as fluorene modification rate) was determined by performing a Raman analysis using a Raman microscope (manufactured by HORIBA JOBIN YVON, XploRA), and the aromatic ring (1604 cm ⁻¹ ) and cellulose ring CH (1375 cm ^{−). 1} ) and the intensity ratio of the absorption band (I ₁₆₀₄ / I ₁₃₇₅ ). In the calculation, a diacetyl cellulose (manufactured by Daicel Corporation) film containing a predetermined amount of a fluorene compound was prepared by a solution cast method, and a calibration curve prepared from these strength ratios (I ₁₆₀₄ / I ₁₃₇₅ ) was used. It was. All samples were measured three times, and the average value calculated from the results was defined as the fluorene modification rate.

(Synthesis of modified cellulose nanofiber)
100 g of an aqueous dispersion of cellulose nanofiber (solid content 15% by weight) was dispersed in 500 g of N, N-dimethylacetamide (DMAc) and centrifuged, and then the precipitated solid was further dispersed in 500 g of DMAc and again. Centrifugation gave a solvent substitution to obtain a mixture of cellulose nanofibers and DMAc (cellulose content about 10% by weight). This mixture was transferred to a 1000 mL three-necked flask, 350 g of DMAc, 9,9-bis (4-glycidyloxyphenyl) fluorene (BPFG) 15 g, and 10 g of diazabicycloundecene (DBU) were added, and the mixture was stirred at 120 ° C. for 3 hours. . The obtained mixed solution was collected by centrifugation, and the process of washing with 1200 mL of DMAc was repeated three times to obtain modified cellulose nanofibers (B-CNF). The obtained B-CNF had an average fiber diameter of 213 nm and an average fiber length of 30 μm. The modification ratio of the fluorene compound was 12% by weight. In addition, the SEM photograph which observed the plant-derived cellulose nanofiber which is the used raw material with SEM (the JEOL Co., Ltd. product "JSM-6510") is shown in FIG.

(Preparation of unmodified cellulose nanofibers)
An aqueous dispersion of cellulose nanofibers (manufactured by Daicel Finechem Co., Ltd., “Cerish KY110N”, cellulose: water (weight ratio) = 15/85) 100 g (solid content 15 g) was dispersed in 500 g of methanol and suction filtered. The precipitated solid content was further dispersed in 500 g of acetone and suction filtered again, and the filtrate was dried to obtain a dried product of unmodified cellulose nanofibers (average fiber diameter 10 nm, average fiber length 100 nm).

(Tensile test)
In accordance with JIS K6251, using a tensile tester (“LTS-1kN” manufactured by Minebea), the vulcanized rubber composition was measured for 25 to 300% tensile stress, tensile strength, and elongation under the following conditions. . In addition, about tensile stress, it selects from the elongation of 25%, 50%, 100%, 200%, and 300% according to an Example, and measures about 100% tensile stress in any Example. The relative values for the corresponding comparative examples were also measured.
Test piece: Dumbbell No. 8, thickness 2mm
Pulling speed: 5mm / min
Initial chuck distance: 30mm
Load cell: 1kN

(Durometer hardness)
Based on JIS K6253 type A, the durometer hardness of the vulcanized rubber composition was measured.

(Mooney viscosity)
The Mooney viscosity of the unvulcanized rubber composition was measured according to JIS K6300.

(density)
The density of the vulcanized rubber composition was measured according to JIS K6268.

Comparative Example 1 (SBR / CB / Blank)
Each component in the ratio shown in Table 1 was kneaded at a temperature of 150 ° C. using a pressure kneader (manufactured by Moriyama Co., Ltd., capacity: 10 liters) to prepare an unvulcanized rubber composition. The obtained composition was press vulcanized at a vulcanization temperature of 180 ° C. to obtain a vulcanized rubber composition.

Example 1 (SBR / CB / B-CNF 3 parts)
With respect to the unvulcanized rubber composition obtained in Comparative Example 1, a modified cellulose nanofiber (B-CNF) was converted into a solid content with respect to 100 parts by weight of the composition of Comparative Example 1 using a 6-inch roll. 3 parts by weight was added to prepare an unvulcanized rubber composition containing modified cellulose nanofibers, and a vulcanized rubber composition was obtained in the same manner as in Comparative Example 1.

Example 2 (5 parts of SBR / CB / B-CNF)
A vulcanized rubber composition was obtained in the same manner as in Example 1 except that the amount of B-CNF added was changed to 5 parts by weight.

Example 3 (SBR / CB / B-CNF 7 parts)
A vulcanized rubber composition was obtained in the same manner as in Example 1 except that the amount of B-CNF added was changed to 7 parts by weight.

Table 2 shows the evaluation results of the vulcanized rubber compositions obtained in Comparative Example 1 and Examples 1 to 3.

As is clear from the results in Table 2, the vulcanized rubber compositions of the examples were improved in 100% tensile stress and hardness as compared with the vulcanized rubber composition of Comparative Example 1.

Comparative Example 2 (SBR / CB / unmodified cellulose nanofiber 3 parts)
A vulcanized rubber composition was obtained in the same manner as in Example 1 except that B-CNF was changed to unmodified cellulose nanofibers.

Comparative Example 3 (SBR / CB / unmodified cellulose nanofiber 5 parts)
A vulcanized rubber composition was obtained in the same manner as in Example 2 except that B-CNF was changed to unmodified cellulose nanofibers.

Comparative Example 4 (SBR / CB / unmodified cellulose nanofiber 7 parts)
A vulcanized rubber composition was obtained in the same manner as in Example 3 except that B-CNF was changed to unmodified cellulose nanofibers.

Table 3 shows the evaluation results of the vulcanized rubber compositions obtained in Comparative Examples 2 to 4 together with the evaluation results of Comparative Example 1.

As is clear from the results in Table 3, even when unmodified cellulose nanofibers were added, the physical properties of SBR were not improved.

Comparative Example 5 (SBR / CB / pulp 3 parts)
A vulcanized rubber composition was obtained in the same manner as in Example 1 except that B-CNF was changed to pulp.

Comparative Example 6 (SBR / CB / pulp 5 parts)
A vulcanized rubber composition was obtained in the same manner as in Example 2 except that B-CNF was changed to pulp.

Comparative Example 7 (SBR / CB / 7 parts of pulp)
A vulcanized rubber composition was obtained in the same manner as in Example 3 except that B-CNF was changed to pulp.

Table 4 shows the evaluation results of the vulcanized rubber compositions obtained in Comparative Examples 5 to 7 together with the evaluation results of Comparative Example 1.

As is clear from the results in Table 4, the hardness increased with the addition of pulp, but the increase in 100% tensile stress was small.

Comparative Example 8 (SBR / silica / blank)
Each component in the ratio shown in Table 5 was kneaded at a temperature of 150 ° C. using a pressure kneader (manufactured by Moriyama Co., Ltd., volume 10 liters) to prepare an unvulcanized rubber composition. The obtained composition was press vulcanized at a vulcanization temperature of 180 ° C. to obtain a vulcanized rubber composition.

Example 4 (3 parts SBR / silica / B-CNF)
With respect to the unvulcanized rubber composition obtained in Comparative Example 8, a modified cellulose nanofiber (B-CNF) was converted into a solid content with respect to 100 parts by weight of the composition of Comparative Example 8 using a 6-inch roll. 3 parts by weight was added to prepare an unvulcanized rubber composition containing modified cellulose nanofibers, and a vulcanized rubber composition was obtained in the same manner as in Comparative Example 8.

Example 5 (SBR / silica / B-CNF 5 parts)
A vulcanized rubber composition was obtained in the same manner as in Example 4 except that the amount of B-CNF added was changed to 5 parts by weight.

Example 6 (SBR / silica / B-CNF 7 parts)
A vulcanized rubber composition was obtained in the same manner as in Example 4 except that the amount of B-CNF added was changed to 7 parts by weight.

Table 6 shows the evaluation results of the vulcanized rubber compositions obtained in Comparative Example 8 and Examples 4 to 6.

As is clear from the results in Table 6, the vulcanized rubber compositions of the examples were improved in tensile stress and hardness by 100 to 300% compared to the vulcanized rubber composition of Comparative Example 8.

Comparative Example 9 (SBR / calcium carbonate / blank)
The components shown in Table 7 were kneaded at a temperature of 150 ° C. using a pressure kneader (manufactured by Moriyama Co., Ltd., volume 10 liters) to prepare an unvulcanized rubber composition. The obtained composition was press vulcanized at a vulcanization temperature of 180 ° C. to obtain a vulcanized rubber composition.

Example 7 (SBR / calcium carbonate / B-CNF 3 parts)
With respect to the unvulcanized rubber composition obtained in Comparative Example 9, a modified cellulose nanofiber (B-CNF) was converted to a solid content amount with respect to 100 parts by weight of the composition of Comparative Example 9 using a 6-inch roll. 3 parts by weight was added to prepare an unvulcanized rubber composition containing modified cellulose nanofibers, and a vulcanized rubber composition was obtained in the same manner as in Comparative Example 9.

Example 8 (SBR / calcium carbonate / B-CNF 5 parts)
A vulcanized rubber composition was obtained in the same manner as in Example 7, except that the amount of B-CNF added was changed to 5 parts by weight.

Table 8 shows the evaluation results of the vulcanized rubber compositions obtained in Comparative Example 9 and Examples 7 to 8.

As is clear from the results in Table 8, the vulcanized rubber compositions of the examples were improved in tensile stress and hardness by 100 to 300% compared to the vulcanized rubber composition of Comparative Example 9.

Comparative Example 10 (EPDM1 / CB / Blank)
The components shown in Table 9 were kneaded at a temperature of 150 ° C. using a pressure kneader (manufactured by Moriyama Co., Ltd., capacity: 10 liters) to prepare an unvulcanized rubber composition. The obtained composition was press vulcanized at a vulcanization temperature of 170 ° C. to obtain a vulcanized rubber composition.

Example 9 (EPDM1 / CB / B-CNF 3 parts)
To the unvulcanized rubber composition obtained in Comparative Example 10, 3 parts by weight of B-CNF was added in terms of solid content with respect to 100 parts by weight of the composition of Comparative Example 10 using a 6-inch roll. An unvulcanized rubber composition containing modified cellulose nanofibers was prepared, and a vulcanized rubber composition was obtained in the same manner as in Comparative Example 10.

Example 10 (EPDM1 / CB / B-CNF 5 parts)
A vulcanized rubber composition was obtained in the same manner as in Example 9, except that the amount of B-CNF added was changed to 5 parts by weight.

Example 11 (EPDM1 / CB / B-CNF 7 parts)
A vulcanized rubber composition was obtained in the same manner as in Example 9, except that the amount of B-CNF added was changed to 7 parts by weight.

Table 10 shows the evaluation results of the vulcanized rubber compositions obtained in Comparative Example 10 and Examples 9 to 11.

As is clear from the results in Table 10, the vulcanized rubber composition of the example improved in 100% tensile stress and hardness as compared with the vulcanized rubber composition of Comparative Example 10.

Comparative Example 11 (EPDM2 / calcium carbonate / blank)
Each component shown in Table 11 was kneaded at a temperature of 150 ° C. using a pressure kneader (manufactured by Moriyama Co., Ltd., volume 10 liters) to prepare an unvulcanized rubber composition. The obtained composition was press vulcanized at a vulcanization temperature of 170 ° C. to obtain a vulcanized rubber composition.

Example 12 (EPDM2 / calcium carbonate / B-CNF 3 parts)
With respect to the unvulcanized rubber composition obtained in Comparative Example 11, a modified cellulose nanofiber (B-CNF) was converted into a solid content with respect to 100 parts by weight of the composition of Comparative Example 11 using a 6-inch roll. 3 parts by weight was added to prepare an unvulcanized rubber composition containing modified cellulose nanofibers, and a vulcanized rubber composition was obtained in the same manner as in Comparative Example 11.

Example 13 (EPDM2 / calcium carbonate / B-CNF 5 parts)
A vulcanized rubber composition was obtained in the same manner as in Example 12 except that the amount of B-CNF added was changed to 5 parts by weight.

Example 14 (EPDM2 / calcium carbonate / B-CNF 7 parts)
A vulcanized rubber composition was obtained in the same manner as in Example 12 except that the amount of B-CNF added was changed to 7 parts by weight.

Table 12 shows the evaluation results of the vulcanized rubber compositions obtained in Comparative Example 11 and Examples 12-14.

As is apparent from the results in Table 12, the vulcanized rubber composition of the example improved in 25 to 300% tensile stress and hardness as compared with the vulcanized rubber composition of Comparative Example 11.

Comparative Example 12 (NBR / CB / Blank)
The components shown in Table 13 were kneaded at a temperature of 150 ° C. using a pressure kneader (manufactured by Moriyama Co., Ltd., capacity 10 liters) to prepare an unvulcanized rubber composition. The obtained composition was press vulcanized at a vulcanization temperature of 160 ° C. to obtain a vulcanized rubber composition.

Example 15 (NBR / CB / B-CNF 3 parts)
To the unvulcanized rubber composition obtained in Comparative Example 12, 3 parts by weight of B-CNF was added in terms of solid content with respect to 100 parts by weight of the composition of Comparative Example 12 using a 6-inch roll. An unvulcanized rubber composition containing modified cellulose nanofibers was prepared, and a vulcanized rubber composition was obtained in the same manner as in Comparative Example 12.

Example 16 (NBR / CB / B-CNF 5 parts)
A vulcanized rubber composition was obtained in the same manner as in Example 15 except that the amount of B-CNF added was changed to 5 parts by weight.

Example 17 (NBR / CB / B-CNF 7 parts)
A vulcanized rubber composition was obtained in the same manner as in Example 15 except that the amount of B-CNF added was changed to 7 parts by weight.

Table 14 shows the evaluation results of the vulcanized rubber compositions obtained in Comparative Example 12 and Examples 15 to 17.

As is clear from the results in Table 14, the vulcanized rubber composition of the example was improved in 100% tensile stress and hardness as compared with the vulcanized rubber composition of Comparative Example 12.

Comparative Example 13 (NBR / calcium carbonate / blank)
The components shown in Table 15 were kneaded at a temperature of 150 ° C. using a pressure kneader (manufactured by Moriyama Co., Ltd., volume 10 liters) to prepare an unvulcanized rubber composition. The obtained composition was press vulcanized at a vulcanization temperature of 160 ° C. to obtain a vulcanized rubber composition.

Example 18 (NBR / calcium carbonate / B-CNF 3 parts)
To the unvulcanized rubber composition obtained in Comparative Example 13, 3 parts by weight of B-CNF was added in terms of solid content with respect to 100 parts by weight of the composition of Comparative Example 13 using a 6-inch roll. An unvulcanized rubber composition containing modified cellulose nanofibers was prepared, and a vulcanized rubber composition was obtained in the same manner as in Comparative Example 13.

Example 19 (NBR / calcium carbonate / B-CNF 5 parts)
A vulcanized rubber composition was obtained in the same manner as in Example 18 except that the amount of B-CNF added was changed to 5 parts by weight.

Example 20 (NBR / calcium carbonate / B-CNF 7 parts)
A vulcanized rubber composition was obtained in the same manner as in Example 18 except that the amount of B-CNF added was changed to 7 parts by weight.

Table 16 shows the evaluation results of the vulcanized rubber compositions obtained in Comparative Example 13 and Examples 18 to 20.

As is clear from the results in Table 16, the vulcanized rubber compositions of the examples were improved in 25 to 300% tensile stress and hardness as compared with the vulcanized rubber composition of Comparative Example 13.

The vulcanized rubber composition of the present invention comprises various industrial members (conveyor belts, rubber cover rolls, gaskets, printing rolls, oil seals, packings, hoses such as oil-resistant hoses, etc.), building members (window frame rubber, vibration damping). Materials, carpet bagging materials, etc.), transportation equipment members (automobile members, tires, power transmission belts, etc.), and electrical / electronic equipment members (electric wire coverings, etc.).

Claims

A vulcanized rubber composition comprising a rubber component (A) and a modified cellulose nanofiber (B) to which a fluorene compound (B1) having an aryl group at the 9th and 9th positions is bonded.
The vulcanized rubber composition according to claim 1, wherein the fluorene compound (B1) is a compound represented by the following formula (1).

Wherein ring Z is an arene ring, R 1 and R 2 are substituents, X 1 is a heteroatom-containing functional group, k is an integer of 0 to 4, n is an integer of 1 or more, and p is an integer of 0 or more. Show)
In Formula (1), X 1 is a group — [(OA) m1 -Y 1 ] (wherein A is an alkylene group, Y 1 is a hydroxyl group or a glycidyloxy group, and m1 represents an integer of 0 or more). The vulcanized rubber composition according to claim 2.
The vulcanized rubber composition according to any one of claims 1 to 3, wherein the proportion of the fluorene compound (B1) is 0.01 to 33% by weight based on the total amount of the modified cellulose nanofibers (B).
The vulcanized rubber composition according to any one of claims 1 to 4, wherein the average fiber diameter of the modified cellulose nanofiber (B) is 4 to 500 nm.
The vulcanized rubber composition according to any one of claims 1 to 5, wherein the rubber component (A) contains at least one selected from the group consisting of diene rubbers and olefin rubbers.
The vulcanized rubber composition according to any one of claims 1 to 6, wherein the proportion of the modified cellulose nanofiber (B) is 0.1 to 30 parts by weight with respect to 100 parts by weight of the rubber component (A).
The vulcanized rubber composition according to any one of claims 1 to 7, further comprising a reinforcing agent (C) and a processing aid (D).
Claims including a kneading step of kneading the rubber component (A), the modified cellulose nanofiber (B) and / or its raw material, and a vulcanizing step of vulcanizing the obtained kneaded composition to obtain a vulcanized rubber composition. Item 9. A method for producing a vulcanized rubber composition according to any one of Items 1 to 8.
The production method according to claim 9, wherein the raw materials of the modified cellulose nanofiber (B) are a fluorene compound (B1) and an unmodified cellulose nanofiber.
The manufacturing method according to claim 9 or 10, wherein in the kneading step, the modified cellulose nanofiber (B) and / or its raw material dispersed in advance in the processing aid (D) is kneaded with the rubber component (A).