Sulfur-containing unsaturated hydrocarbon polymer, additive for rubber, rubber composition, and tire

Abstract

[Problem] To provide a sulfur-containing unsaturated hydrocarbon polymer with which it is possible, by blending into a rubber composition for a tire, to improve a tire's wear resistance, fracture resistance (breaking strength, elongation at break, cut chip resistance), wet grip property, fuel economy, balance between wet grip property and fuel economy, and deterioration resistance (rubber bonding property and heat aging resistance). [Solution] This sulfur-containing unsaturated hydrocarbon polymer is obtained by reacting sulfur with the unsaturated bonds of a polymer of an unsaturated hydrocarbon having a norbornene skeleton, wherein the ratio added in the form of a trisulfide (-S3-) relative to the total amount of unsaturated bonds in the norbornene skeleton is 30 mol% or above.

Description

Sulfur-containing unsaturated hydrocarbon polymer, rubber additive, rubber composition and tire

[0001] The present invention relates to a sulfur-containing unsaturated hydrocarbon polymer. The present invention also relates to a rubber additive containing the sulfur-containing unsaturated hydrocarbon polymer. The present invention further relates to a rubber composition containing the rubber additive. The present invention also relates to a tire manufactured using the rubber composition.

[0002] Traditionally, tires have been manufactured using vulcanized rubber, which is a rubber component to which a vulcanizing agent such as sulfur has been added. For example, when insoluble sulfur is used as a vulcanizing agent, blooming, a phenomenon in which insoluble sulfur migrates to the rubber surface and precipitates during the vulcanization process, can be suppressed. However, this agent has low affinity with rubber and poor dispersibility. To address these issues, the use of a vulcanizing agent composition containing insoluble sulfur and dicyclopentadiene resin has been proposed (see Patent Document 1).

[0003] Furthermore, in recent years, from the viewpoints of resource conservation, energy conservation, and environmental protection, regulations on exhaust gases such as carbon dioxide have become stricter, and there has been a significant increase in the demand for improved fuel economy for automobiles. Therefore, there is a demand for improving fuel economy by improving the rolling resistance of tires. There is also a demand for tires to have improved grip performance on wet road surfaces (wet grip performance). However, the vulcanizing agent composition described in Patent Document 1 does not improve these tire performance characteristics.

[0004] Therefore, the present inventors discovered that a specific sulfur-containing unsaturated hydrocarbon polymer can be used to improve tire performance (particularly wet grip performance and fuel economy) (see Patent Document 2), but further improvements were desired.

[0005] Furthermore, when a rubber component with a high glass transition temperature is used in a rubber composition for a tire for the purpose of improving wet grip performance, or when an additive that increases the glass transition temperature of the rubber component, such as a petroleum resin, is compounded, the abrasion resistance of the tire tends to deteriorate. Therefore, a rubber composition for a tire that improves the abrasion resistance of the tire has been desired.

[0006] International Publication No. 2018 / 189878 Japanese Patent Application Laid-Open No. 2021-31568

[0007] Furthermore, various tire performances are required, such as wear resistance, wet grip performance, and fuel economy, as well as fracture resistance and deterioration resistance, etc. Therefore, there is a demand for the development of tires that combine all of these performances.

[0008] As a result of intensive research conducted by the present inventors to solve the above-mentioned problems, it has been discovered that a sulfur-containing unsaturated hydrocarbon polymer is obtained by reacting sulfur with the unsaturated bonds of a polymer of an unsaturated hydrocarbon having a norbornene skeleton, and that the amount of the trisulfide (-S) is less than the total amount of unsaturated bonds in the norbornene skeleton. ３ The present inventors have found that the above-mentioned various tire performances can be improved by producing a tire using a sulfur-containing unsaturated hydrocarbon polymer in which the ratio of sulfur-containing unsaturated hydrocarbons added in the form of sulfur-containing unsaturated hydrocarbons is adjusted to fall within a specific numerical range, and have thus completed the present invention.

[0009] That is, the present invention provides the following inventions: [1] A sulfur-containing unsaturated hydrocarbon polymer obtained by reacting sulfur with unsaturated bonds of a polymer of an unsaturated hydrocarbon having a norbornene skeleton, wherein the amount of a trisulfide (-S) relative to the total amount of unsaturated bonds in the norbornene skeleton is 100%. ３ [2] A sulfur-containing unsaturated hydrocarbon polymer in which the proportion of trisulfides (-S) added relative to the total amount of unsaturated bonds in the norbornene skeleton is 30 mol % or more. ３The sulfur-containing unsaturated hydrocarbon polymer according to [1], wherein the proportion of sulfur added in the form of hydroxyl groups (-) is 95 mol % or less. [3] The sulfur-containing unsaturated hydrocarbon polymer according to [1] or [2], wherein the polymer of unsaturated hydrocarbon is a petroleum resin. [4] The sulfur-containing unsaturated hydrocarbon polymer according to any one of [1] to [3], wherein the unsaturated hydrocarbon contains a dicyclopentadiene. [5] The sulfur-containing unsaturated hydrocarbon polymer according to any one of [1] to [4], wherein the amount of sulfur added to the polymer of unsaturated hydrocarbon is 0.1 equivalents or more per unsaturated bond of the unsaturated hydrocarbon. [6] A rubber additive comprising the sulfur-containing unsaturated hydrocarbon polymer according to any one of [1] to [5]. [7] The rubber additive according to [6], which is a tire durability improver. [8] A rubber composition comprising the rubber additive according to [6] or [7] and a rubber component. [9] The rubber composition according to [8], which is for use in tires.

[10] A tire manufactured using the rubber composition according to [8] or [9].

[0010] According to the present invention, it is possible to provide a rubber composition for producing a tire that is excellent in abrasion resistance, fracture resistance (breaking strength, breaking elongation, cut-chip resistance), wet grip performance, fuel economy, a balance between wet grip performance and fuel economy, and deterioration resistance (rubber bonding strength, heat aging resistance). Furthermore, according to the present invention, it is possible to produce a tire that is excellent in the various tire performances described above.

[0011] 1 is a chart of the FD-MS spectrum of the petroleum resins used in Preparation Examples 13 to 17. 2 is a chart of the FD-MS spectrum of the sulfur-containing unsaturated hydrocarbon polymer Q produced in Preparation Example 17. 3 is a chart of the FD-MS spectrum of the sulfur-containing unsaturated hydrocarbon polymer N produced in Preparation Example 14.

[0012] [Sulfur-Containing Unsaturated Hydrocarbon Polymer] The sulfur-containing unsaturated hydrocarbon polymer of the present invention is a reaction product obtained by reacting sulfur with the unsaturated bonds of an unsaturated hydrocarbon polymer having a norbornene skeleton, and the sulfur-containing unsaturated hydrocarbon polymer contains a trisulfide (-S) relative to the total amount of unsaturated bonds in the norbornene skeleton. ３In the present invention, the presence of a specific proportion of trisulfides in the sulfur-containing unsaturated hydrocarbon polymer can improve the reactivity with rubber. ２ If the proportion of addition in the form of tetrasulfide (-S) is high, the reactivity with rubber will be low, and ４ When the proportion of sulfur atoms added in the form of sulfur trisulfide (-) or in a form with a larger number of sulfur atoms is high, stability decreases and decomposition, deterioration, etc. are likely to occur. Therefore, even if the total number of sulfur atoms added to unsaturated bonds is the same or larger, if the number of sulfur atoms added in a form other than trisulfide is large, the effect of the present invention may be difficult to achieve or stability may be reduced.

[0013] In a preferred embodiment of the present invention, the trisulfide addition ratio in the sulfur-containing unsaturated hydrocarbon polymer is preferably 35 mol% or more, more preferably 40 mol% or more, even more preferably 45 mol% or more, and still more preferably 50 mol% or more, and may be 95 mol% or less, 93 mol% or less, or 91 mol% or less. If the trisulfide addition ratio in the sulfur-containing unsaturated hydrocarbon polymer is 30 mol% or more, the reactivity of the sulfur-containing unsaturated hydrocarbon polymer with rubber is improved, and a rubber composition for producing a tire excellent in various performances can be provided.

[0014] The trisulfide addition ratio in the sulfur-containing unsaturated hydrocarbon polymer is １ After confirming the progress of the reaction between the unsaturated bond in the norbornene skeleton and sulfur by H-NMR measurement, the reaction product is analyzed by field desorption mass spectrometry (FD-MS measurement), and the mass of the trisulfide is determined by quantifying the molecular peak where an increase in mass of the trisulfide is observed.

[0015] The weight average molecular weight (Mw) of the sulfur-containing unsaturated hydrocarbon polymer is preferably 500 or more, more preferably 600 or more, even more preferably 700 or more, even more preferably 800 or more, and preferably 1500 or less, more preferably 1450 or less, even more preferably 1400 or less, and even more preferably 1350 or less. By reducing the weight average molecular weight of the sulfur-containing hydrocarbon polymer, it is possible to suppress bonding between sulfur-containing hydrocarbon polymers via sulfur, and to increase the amount of sulfur bonding to the rubber component. The weight average molecular weight (Mw) can be measured by a conventionally known GPC (gel permeation chromatography) analysis method.

[0016] In the present invention, a compound having at least an unsaturated bond in a norbornene skeleton as an unsaturated bond for reacting with sulfur can be used as a raw material for the unsaturated hydrocarbon polymer. The unsaturated bond in the norbornene skeleton in the polymer has a strained structure, and therefore has good reactivity with sulfur.

[0017] In a preferred embodiment of the present invention, a petroleum resin obtained by (co)polymerizing a fraction containing an alicyclic unsaturated compound (hereinafter referred to as "alicyclic unsaturated compound-based petroleum resin") is preferably used as the unsaturated hydrocarbon polymer. Alicyclic unsaturated compound-based petroleum resins are obtained, for example, by dimerizing cyclopentadienes contained in a C5 fraction to form dicyclopentadienes, which are then separated from other C5 fractions by distillation and polymerized by a Diels-Alder reaction under heating. Cyclopentadiene compounds include not only cyclopentadiene but also compounds partially substituted with alkyl groups (e.g., methylcyclopentadiene). Dicyclopentadienes include not only dicyclopentadiene (DCPD) but also compounds partially substituted with alkyl groups (e.g., methyldicyclopentadiene).

[0018] Here, the C5 fraction generally refers to the remainder of the boiling range fraction obtained by thermal cracking of petroleum, after removing useful compounds such as ethylene, propylene, and butadiene, and has a boiling range of about 20 to 110° C. In the present invention, the alicyclic unsaturated compound-based petroleum resin may contain a C5 fraction other than cyclopentadienes or a C9 fraction as a fraction.

[0019] Examples of C5 fractions other than cyclopentadienes include olefinic hydrocarbons such as 1-pentene, 2-pentene, 2-methyl-1-butene, 2-methyl-2-butene, and 3-methyl-1-butene, and diolefinic hydrocarbons such as 2-methyl-1,3-butadiene, 1,2-pentadiene, 1,3-pentadiene, and 3-methyl-1,2-butadiene.

[0020] The C9 fraction is generally a fraction having a boiling point range of about 100°C to 280°C, among the boiling point range fractions obtained by thermal cracking of petroleum. Examples of the C9 fraction include styrene homologues such as α-methylstyrene, β-methylstyrene, and γ-methylstyrene, and indene homologues such as indene and coumarone. The alicyclic unsaturated compound petroleum resin of the present invention is produced by the Diels-Alder reaction, but the reaction may also be carried out by adding 0.01 to 5% by weight of a Friedel-Crafts catalyst to the raw materials.

[0021] Typical examples of Friedel-Crafts catalysts include aluminum trichloride, aluminum tribromide, boron trifluoride, or their phenol complexes and butanol complexes. Among these, aluminum trichloride, boron trifluoride phenol complexes, and boron trifluoride butanol complexes are preferred. The polymerization temperature is preferably 0 to 100°C, and particularly preferably 0 to 80°C. The catalyst amount and polymerization time are preferably in the range of 0.1 to 2.0 parts by mass of catalyst per 100 parts by mass of feedstock oil and 0.1 to 10 hours. The reaction pressure is preferably atmospheric pressure to 1 MPa.

[0022] The alicyclic unsaturated petroleum resin of the present invention may be partially polymerized with compounds having various functional groups. Examples of functional groups include alcohol compounds and phenol compounds having hydroxyl groups. Specific examples of alcohol compounds include alcohol compounds having unsaturated bonds such as allyl alcohol and 2-butene-1,4-diol. Examples of phenol compounds that can be used include alkylphenols such as phenol, cresol, xylenol, p-t-butylphenol, p-octylphenol, and p-nonylphenol. These compounds having hydroxyl groups may be used alone or in combination of two or more.

[0023] The polymerization method can be selected from thermal polymerization, mainly the Diels-Alder reaction, in which heating is performed at about 150° C. to 300° C. for about 1 to 10 hours, or the Friedel-Crafts reaction, as mentioned above.

[0024] The above-mentioned resins preferably have a softening point of 200°C or less (measurement method: ASTM E28-58-T), more preferably 45 to 160°C.

[0025] In the present invention, the above-mentioned alicyclic unsaturated compound petroleum resin can also be partially hydrogenated. The hydrogenation conditions are arbitrary, but the alicyclic unsaturated compound petroleum resin is mixed with one or more solvents selected from saturated hydrocarbons, saturated cyclic hydrocarbons, and aromatic hydrocarbons, each having a boiling point of substantially 140 to 280°C at atmospheric pressure, and the mixture is hydrogenated using a general hydrogenation catalyst containing nickel, molybdenum, cobalt, palladium, platinum, etc. at a reaction temperature of 150 to 320°C and a reaction pressure of 30 to 300 kg / cm. ２ The reaction is carried out under the conditions of a reaction time of 1 to 10 hours.

[0026] Usable commercially available products include Neoresin EP-140 (softening point: 140°C) manufactured by ENEOS Corporation, Quintone 1105 (softening point: 107°C) manufactured by Nippon Zeon Co., Ltd., and Quintone 1325 (softening point: 125°C) manufactured by Nippon Zeon Co., Ltd.

[0027] (Method for producing sulfur-containing unsaturated hydrocarbon polymer) The sulfur-containing unsaturated hydrocarbon polymer can be obtained by reacting sulfur with the above-mentioned unsaturated hydrocarbon polymer through an appropriate heating reaction. In this case, a solvent or additive to promote the reaction can be appropriately used. Examples of the solvent include conventionally known organic solvents, aromatic oils, petroleum resins, etc. When a petroleum resin is used, it is preferably a saturated hydrocarbon petroleum resin obtained by hydrogenating the above-mentioned unsaturated hydrocarbon petroleum resin, and saturated DCPD / C9 resin is more preferred. As an additive, conventionally known antioxidants, basic compounds, etc. may be appropriately used. Examples of the basic compound include alkylamines such as hexylamine, heptylamine, octylamine, triethylamine, diisopropylethylamine, and 2-ethylhexylamine; aromatic amines such as aniline, alkylated diphenylamine, and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine; guanidines such as urea, alkylated urea, thiourea, alkylated thiourea, 1,3-diphenylguanidine, and 1,3-di-o-tolylguanidine; pyridines; nitrogen-containing heterocyclic compounds such as hexamethylenetetramine; and sulfenamides such as N,N-biscyclohexylbenzothiazole-2-sulfenamide, N-cyclohexylbenzothiazole-2-sulfenamide, and N-t-butyl-2-benzothiazole sulfenamide.

[0028] The amount of sulfur added to the polymer of unsaturated hydrocarbon is not particularly limited, but is preferably 0.1 equivalents or more, more preferably 0.3 equivalents or more, even more preferably 0.5 equivalents or more, even more preferably 1.0 equivalents or more, and is preferably 5.0 equivalents or less, more preferably 4.0 equivalents or less, even more preferably 3.0 equivalents or less, and even more preferably 2.0 equivalents or less, per unsaturated bond (double bond) of the unsaturated hydrocarbon.

[0029] In the present invention, the unsaturated bonds in the polymer of unsaturated hydrocarbon may remain after the reaction with sulfur, or may be completely consumed. It is also preferable that only the unsaturated bonds in the norbornene skeleton of the polymer of unsaturated hydrocarbon react with sulfur. In the present invention, the fact that the unsaturated bonds in the norbornene skeleton have reacted with sulfur and been consumed can be expressed as follows: １ This can be confirmed by H-NMR.

[0030] The conditions for the heating reaction can be set appropriately depending on the type of unsaturated hydrocarbon polymer and the ratio of sulfur to the polymer, but can be, for example, at 80 to 230°C, preferably 100 to 200°C. In this case, it is more preferable to use highly efficient stirring conditions under heating conditions of 110 to 160°C, to more efficiently react the unsaturated hydrocarbon polymer with sulfur, and to set the reaction time to about 0.1 to 2 hours. As highly efficient stirring conditions, for example, it is preferable to apply stirring at an intensity that gives a power of preferably 10 J / s or more, more preferably 15 J / s or more, per 1 kg of reaction product.

[0031] Sulfur added to unsaturated bonds in unsaturated hydrocarbon polymers is relatively highly reactive, and if it is subjected to a re-reaction, a more preferable form of sulfur addition will be lost. However, by combining the above-mentioned additives, heating conditions, stirring conditions, and reaction time, it is possible to promote the sulfur addition reaction while simultaneously suppressing the re-reaction, and to maintain more of the more preferable form of sulfur addition, compared to conventional methods.

[0032] The resulting reaction product may be purified before use, or may be blended as it is in a rubber composition.

[0033] [Rubber Additive] The rubber additive of the present invention contains the above-mentioned sulfur-containing unsaturated hydrocarbon polymer. The sulfur-containing unsaturated hydrocarbon polymer is as described above. By blending the above-mentioned sulfur-containing unsaturated hydrocarbon polymer into a rubber composition for tires, a tire can be produced that has excellent abrasion resistance, fracture resistance (breaking strength, breaking elongation, cut / chip resistance), wet grip performance, fuel economy, a balance between wet grip performance and fuel economy, and deterioration resistance (rubber bonding ability, heat aging resistance). Therefore, the above-mentioned sulfur-containing unsaturated hydrocarbon polymer can be used as a rubber additive (particularly, a tire durability improver).

[0034] It is known that when a hydrocarbon polymer is compounded into a rubber composition for a tire, the glass transition point (tan δ (0°C) in the measurement of viscoelastic properties in the Examples below) increases, thereby improving the wet grip of the tire, but on the other hand, fuel economy decreases (an increase in tan δ (50°C) in the measurement of viscoelastic properties in the Examples below). In other words, there is a trade-off between the wet grip and fuel economy of a tire, and it has been difficult to improve both in a balanced manner. This is thought to be due to increased energy absorption caused by increased entanglement. In contrast, in the case of a sulfur-containing hydrocarbon polymer, wet grip can be improved without significantly decreasing fuel economy. This is thought to be because the sulfur moiety binds to the rubber, thereby suppressing entanglement movement.

[0035] The rubber additive of the present invention, when blended with a rubber composition for tires, can improve the cut and chip resistance of the tires. Cut and chip refers to a phenomenon in which chunks larger than normal wear debris fall off from the tread and sidewalls of a tire while the tire is running.

[0036] [Rubber Composition] The rubber composition of the present invention contains the above-mentioned rubber additives and a rubber component. The rubber additives are as described above. The amount of the rubber additives mixed is preferably 1 to 30 parts by mass, more preferably 3 to 20 parts by mass, per 100 parts by mass of the rubber component.

[0037] (Rubber Component) The rubber component is not particularly limited, but preferably contains a diene rubber. The sulfur-containing unsaturated hydrocarbon polymer has a higher reactivity with diene rubber and is more likely to react with rubber molecular chains than unsaturated petroleum resin (which does not contain sulfur), which is a general unsaturated hydrocarbon polymer. Therefore, by using a diene rubber, it is possible to improve the wet grip performance and fuel economy of the tire in a balanced manner.

[0038] As the rubber component, a non-diene rubber may be compounded in addition to the diene rubber.

[0039] The content of the diene rubber in the rubber component is preferably 10% by mass or more, more preferably 30% by mass or more, and even more preferably 50% by mass or more.

[0040] Examples of diene rubbers include natural rubber (NR), styrene-butadiene copolymer rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), nitrile rubber (NBR), chloroprene rubber (CR), ethylene-propylene-diene terpolymer rubber (EPDM), butyl rubber (IIR), and modified diene rubbers thereof. Modified diene rubbers include diene rubbers modified by methods such as main chain modification, single-end modification, both-end modification, and hydrogenation. Here, examples of modified functional groups of modified synthetic diene rubbers include various functional groups such as epoxy groups, amino groups, alkoxysilyl groups, and hydroxyl groups, and one or more of these functional groups may be contained in the modified synthetic diene rubber.

[0041] The method for producing the diene rubber is not particularly limited, and examples thereof include emulsion polymerization, solution polymerization, radical polymerization, anionic polymerization, cationic polymerization, etc. The glass transition temperature is also not particularly limited.

[0042] Examples of natural rubber include natural rubber latex, technically graded rubber (TSR), smoked sheet rubber (RSS), gutta percha, eucommia-derived natural rubber, guayule-derived natural rubber, Russian dandelion-derived natural rubber, and plant-based fermented rubber. Furthermore, modified natural rubbers such as epoxidized natural rubber, methacrylic acid-modified natural rubber, styrene-modified natural rubber, sulfonic acid-modified natural rubber, and zinc sulfonate-modified natural rubber are also included in natural rubber.

[0043] The ratio of cis / trans / vinyl unsaturated bonds in natural rubber and synthetic diene rubber is not particularly limited, and any ratio can be suitably used. The number average molecular weight and molecular weight distribution of the diene rubber are not particularly limited, but a number average molecular weight of 500 to 3,000,000 and a molecular weight distribution of 1.5 to 15 are preferred.

[0044] A wide variety of known non-diene rubbers can be used, including, for example, olefin rubbers such as ethylene-propylene rubber (EPM), chlorosulfonated polyethylene rubber (CSM), acrylic rubber (ACM), urethane rubber (U), silicone rubber (VMQ, PVMQ, FVMQ), fluororubber (FKM), and polysulfide rubber (T).

[0045] The rubber composition of the present invention may also contain an elastomer other than the rubber component described above, provided that its functionality is not impaired. Examples of the elastomer include thermoplastic elastomers selected from the group consisting of polystyrene-based elastomeric polymers such as styrene-isoprene-styrene ternary block copolymer (SIS), styrene-butadiene-styrene ternary block copolymer (SBS), and hydrogenated products thereof (SEBS, SEPS, SEEPS), polyolefin-based elastomers, polyvinyl chloride-based elastomers, polyurethane-based elastomers, polyester-based elastomers, and polyamide-based elastomers.

[0046] (Other Processing Aids) The rubber composition of the present invention may contain other processing aids such as a silane coupling agent, a vulcanizing agent, a vulcanization accelerator, a vulcanization acceleration aid, an antioxidant, a softener, an antioxidant, a filler, and a plasticizer, within a range that does not impair its functions.

[0047] When silica is incorporated, it is preferable to incorporate a silane coupling agent. Known silane coupling agents can be used, such as bis[3-(triethoxysilyl)propyl]tetrasulfide, bis[3-(triethoxysilyl)propyl]disulfide, 3-octanoylthio-1-propyltriethoxysilane, and their homocondensates or cocondensates with 3-mercaptopropyltriethoxysilane. Commercially available bis[3-(triethoxysilyl)propyl]tetrasulfide can be used, such as Si-69 manufactured by Evonik. Commercially available bis[3-(triethoxysilyl)propyl]disulfide can also be used, such as Si-75 manufactured by Evonik. Commercially available 3-octanoylthio-1-propyltriethoxysilane may be used, for example, NXT Silane manufactured by Momentive. Commercially available 3-octanoylthio-1-propyltriethoxysilane condensates may be used, for example, NXT Z45 Silane manufactured by Momentive. The amount of silane coupling agent blended is preferably 1 to 20 mass%, more preferably 2 to 10 mass%, of the silica amount.

[0048] Examples of the vulcanizing agent include sulfur-based vulcanizing agents such as powdered sulfur, precipitated sulfur, highly dispersible sulfur, surface-treated sulfur, insoluble sulfur, dimorpholine disulfide, and alkylphenol disulfide, as well as zinc oxide, magnesium oxide, litharge, p-quinone dioxime, p-dibenzoylquinone dioxime, tetrachloro-p-benzoquinone, poly-p-dinitrobenzene, methylene dianiline, phenol resin, brominated alkylphenol resin, and chlorinated alkylphenol resin. The amount of the vulcanizing agent added is preferably 0.1 to 10 parts by mass, and more preferably 1 to 5 parts by mass, per 100 parts by mass of the rubber component.

[0049] Examples of vulcanization accelerators include thiuram-based accelerators such as tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), and tetramethylthiuram monosulfide (TMTM), aldehyde-ammonia-based accelerators such as hexamethylenetetramine, guanidine-based accelerators such as diphenylguanidine (DPG), thiazole-based accelerators such as 2-mercaptobenzothiazole (MBT) and dibenzothiazyl disulfide (DM), sulfenamide-based accelerators such as N-cyclohexyl-2-benzothiazylsulfenamide (CBS) and N-t-butyl-2-benzothiazylsulfenamide (BBS), and dithiocarbamate-based accelerators such as zinc dimethyldithiocarbamate (ZnPDC). The amount of vulcanization accelerator added is preferably 0.1 to 10 parts by mass, and more preferably 1 to 5 parts by mass, per 100 parts by mass of the rubber component.

[0050] Examples of the vulcanization accelerator aid include fatty acids such as acetyl acid, propionic acid, butanoic acid, stearic acid, acrylic acid, and maleic acid, zinc fatty acids such as zinc acetylate, zinc propionate, zinc butanoate, zinc stearate, zinc acrylate, and zinc maleate, and zinc oxide. The amount of the vulcanization accelerator aid added is preferably 0.1 to 10 parts by mass, and more preferably 1 to 5 parts by mass, per 100 parts by mass of the rubber component.

[0051] Examples of the antioxidant include aliphatic and aromatic hindered amine compounds, hindered phenol compounds, etc. The amount of the antioxidant mixed is preferably 0.1 to 10 parts by mass, and more preferably 1 to 5 parts by mass, per 100 parts by mass of the rubber component.

[0052] Examples of antioxidants include butylhydroxytoluene (BHT), butylhydroxyanisole (BHA), etc. The amount of antioxidant mixed is preferably 0.1 to 10 parts by mass, and more preferably 1 to 5 parts by mass, per 100 parts by mass of the rubber component.

[0053] The softener may be any conventionally known softener, and is not particularly limited, but examples thereof include petroleum-based softeners such as aromatic oil, paraffin oil, and naphthenic oil, and plant-based softeners such as palm oil, castor oil, cottonseed oil, and soybean oil. When used, one or more of these may be appropriately selected and used. When a softener is contained, from the viewpoint of ease of handling, it is preferable to contain, among the softeners mentioned above, those that are liquid at room temperature, such as 25°C, for example, petroleum-based softeners such as aromatic oil, paraffin oil, and naphthenic oil, with aromatic oil being particularly preferred. The aromatic oil used is T-DAE (Treated-Distillate Aromatic Extracts: a petroleum-derived rubber softener that can be obtained as an extract fraction obtained by solvent extraction of crude vacuum diesel fuel. To reduce highly carcinogenic polycyclic aromatics, the solvent extraction is performed twice.) Other examples include A / O (Asphalt / Oil) mix and NC-RAE (Residual Aromatic Extracts). The amount of softener mixed is preferably 10 to 200 parts by mass, more preferably 20 to 100 parts by mass, per 100 parts by mass of the rubber component.

[0054] Examples of the filler include silica and barium sulfate, and it is preferable to use silica. The compounding amount of the filler is preferably 10 to 200 parts by mass, more preferably 20 to 100 parts by mass, per 100 parts by mass of the rubber component.

[0055] Examples of colorants include inorganic pigments such as titanium dioxide, zinc oxide, ultramarine, red iron oxide, lithopone, lead, cadmium, iron, cobalt, aluminum, hydrochloride, sulfate, etc., azo pigments, copper phthalocyanine pigments, etc. The blending amount of the colorant is preferably 0.1 to 10 parts by mass, and more preferably 1 to 5 parts by mass, per 100 parts by mass of the rubber component.

[0056] In the present invention, the other processing aids can be used as a rubber composition by kneading them with a known rubber kneading machine, such as a roll, a Banbury mixer, a kneader, etc., and vulcanizing under any conditions. The amounts of these other processing aids added can be conventionally used amounts as long as they do not contradict the object of the present invention.

[0057] [Method for Producing Rubber Composition] The method for producing a rubber composition comprises a step of kneading a rubber component with a rubber additive containing the sulfur-containing unsaturated hydrocarbon polymer.

[0058] The method for producing the rubber composition may preferably further include a step of kneading the vulcanizing agent, and more preferably a step of kneading the vulcanizing agent and the vulcanization accelerator.

[0059] In the method for producing the rubber composition, the above-mentioned other processing aids can be appropriately blended and kneaded within the range that does not impair the function of the rubber composition.

[0060] A conventionally known kneading device can be used to produce the rubber composition, and the kneading temperature, time, compounding order, etc. can be appropriately selected.

[0061] [Tire] A tire can be manufactured using the rubber composition of the present invention by a conventionally known method and common technical knowledge widely known to those skilled in the art. For example, the rubber composition can be extruded, molded using a tire building machine, and then heated and pressurized using a vulcanizer to form crosslinks, thereby manufacturing a tire. By manufacturing a tire using the rubber composition of the present invention, the tire can be improved in terms of abrasion resistance, fracture resistance (breaking strength, breaking elongation, cut-chip resistance), wet grip performance, fuel economy, the balance between wet grip performance and fuel economy, and degradation resistance (rubber bonding, heat aging resistance).

[0062] The use of the tire is not particularly limited, and examples thereof include passenger car tires, heavy-duty tires, motorcycle tires, studless tires, etc. Among these, the tire can be suitably used for passenger car tires.

[0063] The shape, structure, size, and material of the tire are not particularly limited and can be appropriately selected depending on the purpose. In addition, the tire can be applied to various parts of the tire, and the application parts of the tire are not particularly limited and can be appropriately selected depending on the purpose, such as the tread, carcass, sidewall, inner liner, undertread, and belt part of the tire.

[0064] [Rubber Products] The rubber composition of the present invention can also be used to produce rubber products other than tires. Examples of rubber products other than tires include automotive rubber parts (exterior and interior parts, weather strips, boots, mounts, seals, sealers, and gaskets), hoses, belts, sheets, vibration-isolating rubber, rollers, linings, rubber-coated fabrics, sealing materials, gloves, fenders, medical rubber (syringe gaskets, tubes, and catheters), gaskets (for home appliances and construction), asphalt modifiers, grips, toys, shoes, sandals, keypads, gears, and PET bottle cap liners.

[0065] The present invention will be specifically explained below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0066] <Analysis Method> Measurement of Weight Average Molecular Weight (Mw) and Free Sulfur Amount The reaction product obtained below was dissolved in tetrahydrofuran to a concentration of 10 g / L to prepare a measurement sample. The sample was measured using a Tosoh HLC-8320GPC (column used: TSKgel SuperHZ column series) as a measuring device, and the weight average molecular weight (Mw) was calculated using a calibration curve prepared in advance using an Agilent polystyrene kit (EasiVial PS-M and PS-L). In addition, the amount of free sulfur (amount of unreacted sulfur) in the reaction product was quantified by preparing a calibration curve in advance using sulfur (Fujifilm Wako Pure Chemical Industries, Ltd., powder, chemical grade).

[0067] ・Trisulfide (-S ３ Method for measuring -) added norbornene unsaturated bonds / total norbornene unsaturated bonds (mol %) The proportion of sulfur added in the form of trisulfides relative to the total amount of unsaturated bonds in the norbornene skeleton in a sulfur-containing unsaturated hydrocarbon polymer (hereinafter referred to as the "trisulfide addition proportion") can be calculated by measuring a target sample using a conventionally known FD-MS (field desorption-mass spectrometry, apparatus: JEOL Ltd. JMS-T200GCx plus, counter electrode voltage: -10 kV, measurement mass range: m / z 35 to 1600), analyzing the molecular weight of the target sample, and quantifying the molecular peak where an increase in the mass of trisulfides was observed.

[0068] (Preparation Example 1) Synthesis of sulfur-containing unsaturated hydrocarbon polymer A Petroleum resin A (Mw: 810, Mw / Mn: 1.73, softening point 97 ° C, iodine value 169.9, unsaturated bond in the norbornene skeleton 0.146 mol / 100 g of DCPD / C9 resin) 600.00 g was placed in a sealed 1 L metal stirring reaction vessel, and the inside was thoroughly substituted with nitrogen and placed under a nitrogen atmosphere. Next, the reaction vessel was heated to 130 ° C and the temperature was raised to melt the resin. Thereafter, the system was stirred at a rotation speed of 30 rpm using a high-viscosity anchor blade, and 56.31 g (1.76 mol) of sulfur and 28.16 g (0.105 mol) of N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine were added, and the temperature was maintained to start the reaction. Thirty minutes after the start of the reaction, the reaction product was quenched to obtain 648.3 g of a brown resinous solid. １ As a result of H-NMR analysis, consumption of unsaturated bonds in the norbornene skeleton was confirmed at around 5.8 ppm. Furthermore, as a result of GPC analysis, Mw was 1,270, and the amount of free sulfur was 1.7% by mass based on the calibration curve. Furthermore, based on the result of FD-MS analysis, the trisulfide addition ratio was calculated to be 37 mol%.

[0069] (Preparation Example 2) Synthesis of Sulfur-Containing Unsaturated Hydrocarbon Polymer B A reaction was carried out in the same manner as in Preparation Example 1, except that 28.16 g (0.278 mol) of triethylamine was added instead of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, to obtain 646.7 g of a brown resinous solid. １ As a result of H-NMR analysis, consumption of unsaturated bonds in the norbornene skeleton was confirmed at around 5.8 ppm. Furthermore, as a result of GPC analysis, Mw was 1,230, and the amount of free sulfur was 1.1 mass% based on the calibration curve. Furthermore, based on the result of FD-MS analysis, the trisulfide addition ratio was calculated to be 45 mol%.

[0070] (Preparation Example 3) Synthesis of sulfur-containing unsaturated hydrocarbon polymer C A reaction was carried out in the same manner as in Preparation Example 1, except that 0.704 g (0.00545 mol) of octylamine was added instead of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, to obtain 648.3 g of a brown resinous solid. １ As a result of H-NMR analysis, the consumption of unsaturated bonds in the norbornene skeleton was confirmed at around 5.8 ppm. Furthermore, as a result of GPC analysis, Mw was 1,220, and the amount of free sulfur was 2.4 mass% based on the calibration curve. Furthermore, based on the result of FD-MS analysis, the trisulfide addition ratio was calculated to be 30 mol%.

[0071] (Preparation Example 4) Synthesis of Sulfur-Containing Unsaturated Hydrocarbon Polymer D A reaction was carried out in the same manner as in Preparation Example 1, except that 14.08 g (0.109 mol) of octylamine was added instead of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, to obtain 645.5 g of a brown resinous solid. １ As a result of H-NMR analysis, consumption of unsaturated bonds in the norbornene skeleton was confirmed at around 5.8 ppm. Furthermore, as a result of GPC analysis, Mw was 1,260, and the amount of free sulfur was 1.4 mass% based on the calibration curve. Furthermore, based on the result of FD-MS analysis, the trisulfide addition ratio was calculated to be 41 mol%.

[0072] (Preparation Example 5) Synthesis of sulfur-containing unsaturated hydrocarbon polymer E A reaction was carried out in the same manner as in Preparation Example 1, except that 28.16 g (0.218 mol) of octylamine was added instead of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, to obtain 643.7 g of a brown resinous solid. １ As a result of H-NMR analysis, consumption of unsaturated bonds in the norbornene skeleton was confirmed at around 5.8 ppm. Furthermore, as a result of GPC analysis, Mw was 1,270, and the amount of free sulfur was 1.0 mass% based on the calibration curve. Furthermore, based on the result of FD-MS analysis, the trisulfide addition ratio was calculated to be 47 mol%.

[0073] (Preparation Example 6) Synthesis of Sulfur-Containing Unsaturated Hydrocarbon Polymer F A reaction was carried out in the same manner as in Preparation Example 1, except that 28.16 g (0.213 mol) of 1,3-diethylthiourea was added instead of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, to obtain 645.8 g of a brown resinous solid. １ As a result of H-NMR analysis, consumption of unsaturated bonds in the norbornene skeleton was confirmed at around 5.8 ppm. Furthermore, as a result of GPC analysis, Mw was 1,250, and the amount of free sulfur was 0.8% by mass based on the calibration curve. Furthermore, based on the result of FD-MS analysis, the trisulfide addition ratio was calculated to be 50 mol%.

[0074] (Preparation Example 7) Synthesis of sulfur-containing unsaturated hydrocarbon polymer G A reaction was carried out in the same manner as in Preparation Example 1, except that 28.16 g (0.133 mol) of 1,3-diphenylguanidine was added instead of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, to obtain 648.3 g of a brown resinous solid. １ As a result of H-NMR analysis, consumption of unsaturated bonds in the norbornene skeleton was confirmed at around 5.8 ppm. Furthermore, as a result of GPC analysis, Mw was 1,260, and the amount of free sulfur was 0.7% by mass based on the calibration curve. Furthermore, based on the result of FD-MS analysis, the trisulfide addition ratio was calculated to be 52 mol%.

[0075] (Preparation Example 8) Synthesis of sulfur-containing unsaturated hydrocarbon polymer H A reaction was carried out in the same manner as in Preparation Example 1, except that 28.16 g (0.201 mol) of hexamethylenetetramine was added instead of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, to obtain 640.2 g of a brown resinous solid. １ As a result of H-NMR analysis, the consumption of unsaturated bonds in the norbornene skeleton was confirmed at around 5.8 ppm. Furthermore, as a result of GPC analysis, Mw was 1,230, and the amount of free sulfur was 0.3 mass% based on the calibration curve. Furthermore, based on the result of FD-MS analysis, the trisulfide addition ratio was calculated to be 61 mol%.

[0076] (Preparation Example 9) Synthesis of sulfur-containing unsaturated hydrocarbon polymer I A reaction was carried out in the same manner as in Preparation Example 1, except that 28.16 g (0.0813 mol) of N,N-biscyclohexylbenzothiazole-2-sulfenamide was added instead of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, to obtain 644.9 g of a brown resinous solid. １ As a result of H-NMR analysis, the consumption of unsaturated bonds in the norbornene skeleton was confirmed at around 5.8 ppm. Furthermore, as a result of GPC analysis, Mw was 1,280, and the amount of free sulfur was 0.2 mass% based on the calibration curve. Furthermore, based on the result of FD-MS analysis, the trisulfide addition ratio was calculated to be 62 mol%.

[0077] (Preparation Example 10) Synthesis of sulfur-containing unsaturated hydrocarbon polymer J A reaction was carried out in the same manner as in Preparation Example 1, except that 28.16 g (0.107 mol) of N-cyclohexylbenzothiazole-2-sulfenamide was added instead of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, to obtain 643.7 g of a brown resinous solid. １ As a result of H-NMR analysis, consumption of unsaturated bonds in the norbornene skeleton was confirmed at around 5.8 ppm. Furthermore, as a result of GPC analysis, Mw was 1,280, and the amount of free sulfur was 0.2 mass% based on the calibration curve. Furthermore, based on the result of FD-MS analysis, the trisulfide addition ratio was calculated to be 64 mol%.

[0078] (Preparation Example 11) Synthesis of sulfur-containing unsaturated hydrocarbon polymer K A reaction was carried out in the same manner as in Preparation Example 1, except that 28.16 g (0.118 mol) of N-t-butyl-2-benzothiazolesulfenamide was added instead of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, to obtain 651.1 g of a brown resinous solid. １ As a result of H-NMR analysis, consumption of unsaturated bonds in the norbornene skeleton was confirmed at around 5.8 ppm. Furthermore, as a result of GPC analysis, Mw was 1,260, and the amount of free sulfur was 0.1% by mass based on the calibration curve. Furthermore, based on the result of FD-MS analysis, the trisulfide addition ratio was calculated to be 67 mol%.

[0079] (Preparation Example 12) Synthesis of Sulfur-Containing Unsaturated Hydrocarbon Polymer L 50.00 g of petroleum resin A and 100.00 g of mesitylene (186.05 mL, equivalent to 33 wt % of the resin in the solution) were placed in a 300 ml two-necked eggplant flask and allowed to stand for 30 minutes to half a day until completely dissolved. Next, 7.01 g (0.219 mol) of sulfur was added, and a stirrer bar, reflux condenser, and ball stopper were installed. The interior was thoroughly purged with nitrogen to create a nitrogen atmosphere. The system was then stirred at approximately 300 rpm, and the temperature was gradually increased to 160°C in an oil bath to allow the reaction to proceed. After 7 hours at 160°C, the oil bath was removed and the mixture was allowed to cool to room temperature, after which the stirring was stopped. The reddish-brown reaction liquid was then recovered from the reactor. The reaction liquid １ H-NMR analysis was performed to confirm the consumption of unsaturated bonds in the norbornene skeleton near 5.8 ppm. Next, 1.15 kg of acetone and a stirrer bar were placed in a 2-L beaker and vigorously stirred. Approximately 80 g of the resulting reaction solution was added dropwise to the stirred solution. After the addition was complete, the stirring state was maintained for 5 minutes, after which the stirring was stopped and the solids were recovered by suction filtration. The series of steps from precipitation to filtration was repeated three times for each study, and solids were recovered for the entire reaction solution. The resulting solids were dried under reduced pressure at 0.1 kPa and 50°C for approximately 8 hours, yielding 41.4 g of a brown powdery solid. GPC analysis of the resulting solids showed a Mw of 4,030, and the free sulfur content was 0.2% by mass based on the calibration curve. Furthermore, based on the results of FD-MS analysis, the trisulfide addition ratio was calculated to be 18 mol%.

[0080] (Preparation Example 13) Synthesis of Sulfur-Containing Unsaturated Hydrocarbon Polymer M A reaction was carried out in the same manner as in Preparation Example 1, except that 600 g of petroleum resin B (DCPD / C9 resin having Mw: 660, Mw / Mn: 1.70, softening point 101°C, iodine value 197.6, and 0.226 mol of unsaturated bonds in the norbornene skeleton per 100 g of resin) was used instead of petroleum resin A, the amount of sulfur added was 86.78 g (2.71 mol), and 28.93 g (0.224 mol) of octylamine was added instead of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, to obtain 643.1 g of a brown resinous solid.１ As a result of H-NMR analysis, consumption of unsaturated bonds in the norbornene skeleton was confirmed at around 5.8 ppm. Furthermore, as a result of GPC analysis, Mw was 1,170, and the amount of free sulfur was 2.9 mass% based on the calibration curve. Furthermore, based on the result of FD-MS analysis, the trisulfide addition ratio was calculated to be 62 mol%.

[0081] (Preparation Example 14) Synthesis of sulfur-containing unsaturated hydrocarbon polymer N A reaction was carried out in the same manner as in Preparation Example 13, except that 28.93 g (0.206 mol) of hexamethylenetetramine was added instead of octylamine, to obtain 650.3 g of a brown resinous solid. １ As a result of H-NMR analysis, consumption of unsaturated bonds in the norbornene skeleton was confirmed at around 5.8 ppm. Furthermore, as a result of GPC analysis, Mw was 1,150, and the amount of free sulfur was 0.6% by mass based on the calibration curve. Furthermore, based on the result of FD-MS analysis, the trisulfide addition ratio was calculated to be 83 mol%.

[0082] Preparation Example 15 Synthesis of Sulfur-Containing Unsaturated Hydrocarbon Polymer O A reaction was carried out in the same manner as in Preparation Example 13, except that 28.93 g (0.109 mol) of N-cyclohexylbenzothiazole-2-sulfenamide was added instead of octylamine, to obtain 647.8 g of a brown resinous solid. １ As a result of H-NMR analysis, consumption of unsaturated bonds in the norbornene skeleton was confirmed at around 5.8 ppm. Furthermore, as a result of GPC analysis, Mw was 1,160, and the amount of free sulfur was 0.2 mass% based on the calibration curve. Furthermore, based on the result of FD-MS analysis, the trisulfide addition ratio was calculated to be 88 mol%.

[0083] (Preparation Example 16) Synthesis of sulfur-containing unsaturated hydrocarbon polymer P A reaction was carried out in the same manner as in Preparation Example 13, except that 28.93 g (0.0813 mol) of N,N-biscyclohexylbenzothiazole-2-sulfenamide was added instead of octylamine, to obtain 645.1 g of a brown resinous solid. １As a result of H-NMR analysis, consumption of unsaturated bonds in the norbornene skeleton was confirmed at around 5.8 ppm. Furthermore, as a result of GPC analysis, Mw was 1,190, and the amount of free sulfur was 0.1% by mass based on the calibration curve. Furthermore, based on the result of FD-MS analysis, the trisulfide addition ratio was calculated to be 90 mol%.

[0084] (Preparation Example 17) Synthesis of Sulfur-Containing Unsaturated Hydrocarbon Polymer Q 50.00 g of petroleum resin B and 100.00 g of mesitylene (186.05 mL, equivalent to 33 wt % of the resin in the solution) were placed in a 300 ml two-necked flask and allowed to stand for 30 minutes to half a day until completely dissolved. Next, 10.85 g (0.339 mol) of sulfur was added, and a stirrer bar, reflux condenser, and ball stopper were installed. The interior was thoroughly purged with nitrogen to create a nitrogen atmosphere. The system was then stirred at approximately 300 rpm, and the temperature was gradually increased to 160°C in an oil bath to allow the reaction to proceed. After 7 hours at 160°C, the oil bath was removed and the mixture was allowed to cool to room temperature, after which the stirring was stopped. The reddish-brown reaction liquid was then recovered from the reactor. The reaction liquid １ H-NMR analysis was performed to confirm the consumption of unsaturated bonds in the norbornene skeleton at around 5.8 ppm. Next, 1.15 kg of acetone and a stirrer bar were placed in a 2 L beaker and the mixture was stirred vigorously. Approximately 80 g of the resulting reaction solution was added dropwise to the stirred solution, and after the addition was completed, the stirring state was maintained for 5 minutes. Then, the stirring was stopped and the solids were recovered by suction filtration. The series of steps from precipitation to filtration up to this point was repeated three times for each study, and solids were recovered from the entire reaction solution. GPC analysis of the resulting solids showed Mw: 1,640, and the amount of free sulfur from the calibration curve was 0.4% by mass. Furthermore, from the results of FD-MS analysis, the trisulfide addition ratio was calculated to be 23 mol%.

[0085] 1 to 3 show FD-MS spectrum charts of the petroleum resin B used in the above Preparation Examples 13 to 17, the sulfur-containing unsaturated hydrocarbon polymer Q produced in Preparation Example 17, and the sulfur-containing unsaturated hydrocarbon polymer N produced in Preparation Example 14. From FIGS. 1 to 3, the charts of each sulfur-containing unsaturated hydrocarbon polymer and the chart of the raw material petroleum resin B can be compared and analyzed, and the molecular peak where an increase in mass of the trisulfide (peak shift) was observed can be quantified to calculate the trisulfide addition ratio. More specifically, the proportion of added trisulfide was calculated from the ratio of the peak intensity of a trisulfide (396 + 96 = approximately 492 m / z) in which three sulfur atoms (molecular weight 32.1 × 3 = approximately 96 m / z) were added to a cyclopentadiene hexamer (molecular weight 66.1 × 6 = approximately 396 m / z) to the peak intensity of the cyclopentadiene hexamer (approximately 396 m / z) before sulfur addition.

[0086] Tables 1 and 2 show the raw material composition and trisulfide addition ratio for each preparation example. Tables 1 and 2 also show the amount of free sulfur in the reaction product and the average amount of sulfur introduced. The amount of free sulfur in the reaction product refers to the amount of unreacted sulfur remaining after sulfur is consumed in the target reaction (adding sulfur to unsaturated bonds in the norbornene skeleton) and other side reactions (resin-sulfur-resin bonding to increase molecular weight). The average amount of sulfur introduced is a value calculated using the following formula: Average amount of sulfur introduced = (amount of charged sulfur - amount of free sulfur) / amount of unsaturated bonds in the norbornene skeleton. From the above formula, a decrease in the amount of free sulfur increases the average amount of sulfur introduced, but at the same time, the progression of the side reaction is also a concern. In the present invention, the balance between a low weight-average molecular weight and a high average amount of sulfur introduced can be used as an indicator of the progress of the target reaction. In Preparation Example 12, the amount of free sulfur in the reaction product was low and the weight-average molecular weight was high, suggesting that a large amount of sulfur was consumed in the side reaction other than the target reaction. On the other hand, compared with Preparation Example 12, it is presumed that in Preparation Examples 1 to 11, the above-mentioned side reactions do not proceed so much, and the above-mentioned target reaction proceeds predominantly.

[0087]

[0088]

[0089] (Synthesis Example of Conjugated Diene Polymer) A nitrogen-purged 5 L autoclave reactor was charged with 2,000 g of cyclohexane, 2.5 mL of tetrahydrofuran as a vinyl content adjuster, 0.08 mmol of potassium 4-dodecylbenzenesulfonate as a potassium compound, and 175 g of styrene and 150 g of 1,3-butadiene as polymerization monomers. After adjusting the temperature of the reactor contents to 35°C, 3.7 mmol of n-butyllithium was added as a polymerization initiator to initiate polymerization. When the polymerization conversion reached 20% (corresponding to the point when the temperature of the contents reached 45°C), 175 g of 1,3-butadiene (additional amount) was added to the reactor at a constant feed rate over 25 minutes. The polymerization was carried out under adiabatic conditions, and the maximum temperature reached 85°C. When the polymerization conversion rate reached 99% (35 minutes after the start of polymerization), 3.7 mmol of 3-(N,N-bistrimethylsilyl)aminopropylmethyldiethoxysilane was added as a terminal modifier, and the mixture was stirred for 10 minutes. After stirring, 4.40 g of 2,6-di-tert-butyl-p-cresol was added as an antioxidant to the polymer solution, followed by steam stripping to remove the solvent and drying with a heated roll adjusted to 130°C to obtain a conjugated diene-based polymer.

[0090] Example 1 The following components were kneaded using a 250 mL kneader (Labo Plastomill, manufactured by Toyo Seiki Seisakusho, Ltd.) to obtain a rubber composition. Details of the kneading operation performed are as follows (i) to (ii). (i) Kneading 1: A rubber (conjugated diene polymer) was charged into an internal pressure kneader heated to 100°C, followed by silica, carbon black, aroma oil, stearic acid, an antioxidant, zinc oxide, a silane coupling agent, and a sulfur-containing unsaturated hydrocarbon polymer A. The mixture was kneaded at 60 rpm for 3 minutes and 30 seconds and then discharged. (ii) Kneading 2: After the temperature had sufficiently decreased after the discharge, a vulcanization accelerator and sulfur were added to the above kneaded mixture in an internal pressure kneader heated to 70°C, and the mixture was kneaded to obtain a rubber composition. Rubber (the conjugated diene polymer synthesized above) 100 parts by mass Silica (manufactured by Tosoh Corporation, trade name: Nipsil AQ) 70 parts by mass Silane coupling agent (manufactured by Degussa Corporation, trade name: Si75) 5.6 parts by mass Carbon black (manufactured by Tokai Carbon Co., Ltd., trade name: Seest KH) 5.6 parts by mass Aroma oil (manufactured by ENEOS Corporation, trade name: T-DAE) 10 parts by mass Sulfur-containing unsaturated hydrocarbon polymer A 10 parts by mass Stearic acid (manufactured by New Japan Chemical Co., Ltd., trade name: Stearic Acid 300) 2 parts by mass Antiaging agent (manufactured by Ouchi Shinko Chemical Co., Ltd., trade name: Nocrac 6C) 1 part by mass Zinc oxide (manufactured by Toho Zinc Co., Ltd., trade name: Ginrei R) 3 parts by mass Vulcanization accelerator (manufactured by Ouchi Shinko Chemical Co., Ltd., trade name: Noccela D) 2 parts by mass Vulcanization accelerator (manufactured by Ouchi Shinko Chemical Co., Ltd., product name: Noccela CZ) 1.8 parts by mass Sulfur (manufactured by Hosoi Chemical Co., Ltd., 5% oil-treated sulfur) 1 part by mass

[0091] Example 2 A rubber composition was obtained in the same manner as in Example 1, except that the sulfur-containing unsaturated hydrocarbon polymer B was used instead of the sulfur-containing unsaturated hydrocarbon polymer A.

[0092] Example 3 A rubber composition was obtained in the same manner as in Example 1, except that the sulfur-containing unsaturated hydrocarbon polymer C was used instead of the sulfur-containing unsaturated hydrocarbon polymer A.

[0093] Example 4 A rubber composition was obtained in the same manner as in Example 1, except that the sulfur-containing unsaturated hydrocarbon polymer D was used instead of the sulfur-containing unsaturated hydrocarbon polymer A.

[0094] Example 5 A rubber composition was obtained in the same manner as in Example 1, except that the sulfur-containing unsaturated hydrocarbon polymer E was used instead of the sulfur-containing unsaturated hydrocarbon polymer A.

[0095] Example 6 A rubber composition was obtained in the same manner as in Example 1, except that the sulfur-containing unsaturated hydrocarbon polymer F was used instead of the sulfur-containing unsaturated hydrocarbon polymer A.

[0096] Example 7 A rubber composition was obtained in the same manner as in Example 1, except that the sulfur-containing unsaturated hydrocarbon polymer G was used instead of the sulfur-containing unsaturated hydrocarbon polymer A.

[0097] Example 8 A rubber composition was obtained in the same manner as in Example 1, except that the sulfur-containing unsaturated hydrocarbon polymer H was used instead of the sulfur-containing unsaturated hydrocarbon polymer A.

[0098] Example 9 A rubber composition was obtained in the same manner as in Example 1, except that the sulfur-containing unsaturated hydrocarbon polymer I was used instead of the sulfur-containing unsaturated hydrocarbon polymer A.

[0099] Example 10 A rubber composition was obtained in the same manner as in Example 1, except that the sulfur-containing unsaturated hydrocarbon polymer J was used instead of the sulfur-containing unsaturated hydrocarbon polymer A.

[0100] Example 11 A rubber composition was obtained in the same manner as in Example 1, except that the sulfur-containing unsaturated hydrocarbon polymer K was used instead of the sulfur-containing unsaturated hydrocarbon polymer A.

[0101] Comparative Example 1 A rubber composition was obtained in the same manner as in Example 1, except that the sulfur-containing unsaturated hydrocarbon polymer L was used instead of the sulfur-containing unsaturated hydrocarbon polymer A.

[0102] Example 12 A rubber composition was obtained in the same manner as in Example 1, except that the sulfur-containing unsaturated hydrocarbon polymer M was used instead of the sulfur-containing unsaturated hydrocarbon polymer A.

[0103] Example 13 A rubber composition was obtained in the same manner as in Example 1, except that the sulfur-containing unsaturated hydrocarbon polymer N was used instead of the sulfur-containing unsaturated hydrocarbon polymer A.

[0104] Example 14 A rubber composition was obtained in the same manner as in Example 1, except that the sulfur-containing unsaturated hydrocarbon polymer O was used instead of the sulfur-containing unsaturated hydrocarbon polymer A.

[0105] Example 15 A rubber composition was obtained in the same manner as in Example 1, except that the sulfur-containing unsaturated hydrocarbon polymer P was used instead of the sulfur-containing unsaturated hydrocarbon polymer A.

[0106] Comparative Example 2 A rubber composition was obtained in the same manner as in Example 1, except that the sulfur-containing unsaturated hydrocarbon polymer Q was used instead of the sulfur-containing unsaturated hydrocarbon polymer A.

[0107] [Evaluation of Physical Properties] Physical properties were evaluated by the following methods using the rubber compositions obtained in Examples 1 to 15 and Comparative Examples 1 and 2. The evaluation results are shown in Tables 3 and 4.

[0108] (Wear Resistance) Each rubber composition was molded into a disk-shaped sample having a diameter of 16.0 mm and a thickness of 8 mm. Next, using each of the obtained disk-shaped samples, a wear resistance test was performed using a DIN abrasion tester (rotating cylindrical abrasion tester: manufactured by Yasuda Seiki Co., Ltd. under the trade name "DIN Abrasion Tester") in accordance with JIS K6264-2 (issued in 2005) under the following conditions: temperature: room temperature (25 ° C), load: 10 N, drum rotation speed: 40 rpm, sample lateral feed speed: 2.8 mm / sec, and the wear amount (volume basis: the ratio (volume%) of the volume worn by the test to the total volume before wear) was measured. Examples 1 to 11 are reported as the reciprocal of the relative value when the value in Comparative Example 1 is set to 100, and Examples 12 to 15 are reported as the reciprocal of the relative value when the value in Comparative Example 2 is set to 100. The larger the value, the better the wear resistance.

[0109] (Mechanical Properties) Each rubber composition was placed in a sheet mold and heated and pressed at 160°C and 20 MPa for 40 minutes to obtain a 2 mm thick vulcanized rubber sheet. No. 3 dumbbell-shaped test pieces were punched out from the obtained vulcanized rubber sheet, and the breaking strength (MPa) and breaking elongation (%) were measured at a temperature of 20°C and a tensile speed of 500 mm / min in accordance with JIS K6251 (issued in 2010). A higher breaking strength value indicates higher strength, and a higher breaking elongation value indicates better elongation.

[0110] (Cut and Chip Resistance) From the measurement results of the breaking strength (MPa) and breaking elongation (%), the tensile product (=breaking strength × breaking elongation / 2) was calculated. The tensile product values ​​for Examples 1 to 11 are reported as relative values ​​when the value for Comparative Example 1 is set to 100, and the values ​​for Examples 12 to 15 are reported as relative values ​​when the value for Comparative Example 2 is set to 100. The larger the value, the better the cut and chip resistance of the tire.

[0111] (Wet Grip Performance and Fuel Economy) For the vulcanized rubber sheet obtained above, tan δ was determined at measurement temperatures of 0°C and 50°C using a viscoelasticity spectrometer (REOGEL E-4000 manufactured by UBM) in accordance with JIS K 6394 in tensile mode under conditions of a strain of approximately 0.1% and a frequency of 10 Hz, and the tan δ balance (= tan δ (0°C) / tan δ (50°C)) was calculated from these values. For Examples 1 to 11, the values ​​are reported as relative values ​​with the value for Comparative Example 1 taken as 100, and for Examples 12 to 15, the values ​​are reported as relative values ​​with the value for Comparative Example 2 taken as 100. A higher tan δ (0°C) indicates better wet grip performance, and a lower tan δ (50°C) indicates better fuel economy. Therefore, the tan δ balance (= tan δ (0°C) / tan δ (50°C)) is a value that serves as a relative indicator of wet grip performance and fuel economy, and the larger this value, the better the balance between wet grip performance and fuel economy.

[0112] (Rubber Bondability) Test pieces of appropriate size were cut out from the vulcanized rubber sheet obtained above. Next, using the test pieces, a solvent extraction test was performed in accordance with JIS K6229B, and the rubber bondability was evaluated from the amount of extraction. For Examples 1 to 11, the value was reported as the reciprocal of the relative value when the value for Comparative Example 1 was set to 100, and for Examples 12 to 15, the value was reported as the reciprocal of the relative value when the value for Comparative Example 2 was set to 100. A larger value indicates a smaller amount of extraction and higher rubber bondability.

[0113] (Heat Aging Resistance) JIS No. 3 dumbbell-shaped test pieces were punched out from the vulcanized rubber sheet obtained above, and a tensile test was performed in accordance with JIS K6251 at a tensile speed of 500 mm / min. The breaking strength (TB) [MPa] and breaking elongation (EB) [%] before heat aging were measured at room temperature (23°C). Next, using the same test pieces, they were left in a gear oven (A45A2, manufactured by Toyo Seiki Seisaku-sho, Ltd.) at 100°C for 72 hours, and then the breaking strength (TB) [MPa] and breaking elongation (EB) [%] after heat aging were measured. Heat aging resistance was evaluated based on the rate of change in breaking strength and breaking elongation before and after heat aging. For Examples 1 to 11, values ​​are reported relative to the value for Comparative Example 1, which is set to 100. For Examples 12 to 15, values ​​are reported relative to the value for Comparative Example 2, which is set to 100. The smaller the value, the smaller the rate of change in breaking strength and breaking elongation, indicating superior heat aging resistance.

[0114]

[0115]

[0116] In Examples 1 to 11, by adding a sulfur-containing unsaturated hydrocarbon polymer with an addition ratio of 30 mol% or more of trisulfide, the tires were superior in abrasion resistance, fracture resistance (breaking strength, breaking elongation, cut-chip resistance), wet grip performance, fuel economy, the balance between wet grip performance and fuel economy, and degradation resistance (rubber bonding ability and heat aging resistance) compared to Comparative Example 1, in which a sulfur-containing unsaturated hydrocarbon polymer with an addition ratio of 18 mol% of trisulfide was added. Also, in Examples 12 to 15, by adding a sulfur-containing unsaturated hydrocarbon polymer with an addition ratio of 30 mol% or more of trisulfide, the tires were superior in abrasion resistance, fracture resistance (breaking strength, breaking elongation, cut-chip resistance), wet grip performance, fuel economy, the balance between wet grip performance and fuel economy, and degradation resistance (rubber bonding ability and heat aging resistance) compared to Comparative Example 2, in which a sulfur-containing unsaturated hydrocarbon polymer with an addition ratio of 23 mol% of trisulfide was added.

Claims

1. A sulfur-containing unsaturated hydrocarbon polymer obtained by reacting sulfur with the unsaturated bonds of a polymer of an unsaturated hydrocarbon having a norbornene skeleton, wherein the amount of a trisulfide (-S) relative to the total amount of unsaturated bonds in the norbornene skeleton is 1. ３ -) is added in an amount of 30 mol % or more.

2. The amount of trisulfide (-S) relative to the total amount of unsaturated bonds in the norbornene skeleton ３ 2. The sulfur-containing unsaturated hydrocarbon polymer according to claim 1, wherein the proportion of the sulfur-containing unsaturated hydrocarbon polymer added in the form of hydroxyl groups is 95 mol % or less.

3. The sulfur-containing unsaturated hydrocarbon polymer according to claim 1, wherein the polymer of the unsaturated hydrocarbon is a petroleum resin.

4. The sulfur-containing unsaturated hydrocarbon polymer according to claim 1, wherein the unsaturated hydrocarbon comprises a dicyclopentadienes.

5. The sulfur-containing unsaturated hydrocarbon polymer according to claim 1, wherein the amount of sulfur added to the polymer of unsaturated hydrocarbon is 0.1 equivalents or more per unsaturated bond of the unsaturated hydrocarbon.

6. A rubber additive comprising the sulfur-containing unsaturated hydrocarbon polymer according to any one of claims 1 to 5.

7. The rubber additive according to claim 6, which is a tire durability improver.

8. A rubber composition comprising the rubber additive according to claim 6 and a rubber component.

9. The rubber composition according to claim 8, which is for use in tires.

10. A tire manufactured using the rubber composition of claim 8.

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