Bale molded product of rubber composition, method for manufacturing bale molded product of rubber composition, rubber composition for crosslinking, and tire tread

Abstract

To provide a molded bale of a rubber composition that prevents a molding die from being contaminated, prevents the rubber composition from rising in viscosity with time, prevents the rubber composition from peeling off from the molded bale, and facilitates the adhering of a packaging sheet to the molded bale.SOLUTION: A molded bale of a rubber composition contains: a rubber-like polymer (A) having an iodine value of 10 to 250, 3 mass% or more of an ethylene structure, and less than 10 mass% of a vinyl aromatic monomer block; and titanium (C), in which a content of the titanium (C) is 3 ppm or more and 120 ppm or less, and a content of aluminum (B) is less than 2 ppm.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a bale molded product of a rubber composition, a method for producing a bale molded product of a rubber composition, a rubber composition for crosslinking, and a tread for a tire. [Background technology]

[0002] In recent years, in the field of rubber materials for tire treads, sheets, films, and asphalt modification, rubber compositions containing rubber-like polymers having an ethylene structure and into which crosslinkable unsaturated groups have been introduced have been proposed for the purpose of increasing mechanical strength and compression set (see, for example, Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 151126 [Patent Document 2] International Publication No. 2019 / 151127 [Patent Document 3] International Publication No. 2019 / 078083 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventionally proposed rubber compositions containing rubbery polymers having an ethylene structure and incorporating crosslinkable unsaturated groups have problems such as the tendency for molding dies to be easily contaminated, for the rubber composition to increase in viscosity over time, and for the rubber composition to peel off from the bale molded product. The present inventors have also found that bales made from rubber compositions containing rubbery polymers having an ethylene structure have problems such as the tendency for the packaging sheet encasing the bale to tear easily during transportation, making the bale wrapped in the sheet difficult to transport. This is thought to be because when the rubbery polymer has an ethylene structure, the packaging sheet does not adhere well to the bale molded from the rubber composition.

[0005] Therefore, an object of the present invention is to provide a bale molded product of a rubber composition that is less likely to contaminate the molding die, that is less likely to increase in viscosity over time, that is less likely to peel off from the bale molded product, and that allows a packaging sheet to easily adhere to the bale molded product. [Means for solving the problem]

[0006] The present inventors have conducted extensive research and investigation to solve the problems of the prior art described above, and as a result have discovered that by specifying the titanium content and aluminum content within predetermined ranges in a rubber composition containing a rubbery polymer of a specific structure, the molding die is less likely to be contaminated, the viscosity of the rubber composition is less likely to increase over time, the rubber composition is less likely to peel off from the bale molded body, and a packaging sheet can be more easily adhered to the bale molded body, thereby completing the present invention. That is, the present invention is as follows.

[0007] [1] A hydrogenated conjugated diene polymer containing 5% by mass or more of vinyl aromatic monomer units and having a modification rate of 40% by mass or more as measured by a column adsorption GPC method; Iodine value is 10 or more 140 A rubbery polymer (A) having an ethylene structure of 3% by mass or more and a vinyl aromatic monomer block of less than 10% by mass; Titanium (C) and Contains The titanium (C) content is 3 ppm or less and 120 ppm or less. A bale molded product of a rubber composition having an aluminum (B) content of less than 2 ppm. 〔2〕 The rubber polymer (A) contains a nitrogen atom. 〔1〕 The bale molded body according to claim 1. 〔3〕 [1] The rubber softener (D) is further contained in an amount of 30 mass% or less. or [2] The bale molded body according to claim 1. 〔4〕 The above [1] to [3], which contain water in an amount of 0.05% by mass or more and 1.5% by mass or less. 〔3〕 The bale molded body according to any one of the above. 〔5〕 [1] to 〔4〕 A method for producing a bale molded product of the rubber composition according to any one of the above, a step of polymerizing at least a conjugated diene monomer in a solution to obtain a rubbery polymer (A); a step of adding titanium (C) to the obtained solution containing the rubbery polymer (A) to obtain a rubber composition; a step of molding the obtained rubber composition; A method for producing a bale molded article of a rubber composition, comprising: 〔6〕 The hydrogenation step is carried out using a hydrogenation catalyst having an aluminum content of 0.05 moles or less per mole of titanium content. 〔5〕 A method for producing the bale molded body described in claim 1. 〔7〕 removing the solvent from the solution by steam stripping. [5] or [6] A method for producing the bale molded body described in claim 1. 〔8〕 [1] to 〔4〕 a rubber composition for a bale molded product according to any one of the above items; a cross-linking agent; Contains The rubber composition for crosslinking contains the crosslinking agent in an amount of 0.1 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the rubber component. 〔9〕 [1] to 〔4〕 A tread for a tire, comprising the rubber composition for the bale molded body according to any one of the above items. [Effects of the Invention]

[0008] According to the present invention, a rubber composition can be obtained that is less likely to contaminate molding dies, is less likely to increase in viscosity over time, is less likely to peel off from a bale molded body, and allows a packaging sheet to easily adhere to the bale molded body. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail. It should be noted that the following embodiments are merely examples for explaining the present invention, and the present invention is not limited to the following embodiments. The present invention can be practiced by appropriately modifying it within the scope of its gist.

[0010] [Bale molded product of rubber composition] The bale molded product of the rubber composition of this embodiment is a bale molded product of the rubber composition, which contains a rubber-like polymer (A) having an iodine value of 10 to 250, an ethylene structure of 3 mass% or more, and a vinyl aromatic monomer block of <10 mass%, and titanium (C), in which the titanium (C) content is 3 ppm or less and 120 ppm or less, and the aluminum (B) content is less than 2 ppm.

[0011] (Rubber polymer (A)) The rubber-like polymer (A) contained in the rubber composition constituting the bale molded product of this embodiment (hereinafter referred to as the rubber composition of this embodiment) is a rubber-like polymer having an iodine value of 10 to 250, an ethylene structure content of 3% by mass or more, and a vinyl aromatic monomer block content of <10% by mass.

[0012] <Iodine value> The rubbery polymer (A) constituting the rubber composition of this embodiment has an iodine value of 10-250. The iodine value is 10 or more from the viewpoint of ease of crosslinking and adhesion of a packaging sheet to a bale molded product of the rubber composition of this embodiment, preferably 15 or more, more preferably 30 or more, even more preferably 50 or more, and even more preferably 70 or more. On the other hand, from the viewpoint of the weather resistance and resistance to deterioration over time of the rubbery polymer (A) and the mechanical strength and abrasion resistance when made into a tire, it is 250 or less, preferably 170 or less, more preferably 140 or less, even more preferably 110 or less, and even more preferably 80 or less. The iodine value can be measured according to the method described in "JIS K 0070:1992". The iodine value is a value that expresses the amount of halogen that reacts with 100 g of the target substance, converted into grams of iodine, so the unit of the iodine value is "g / 100 g". Since the conjugated diene monomer unit has a double bond, in the production method of the rubbery polymer (A) described below, for example, when a conjugated diene monomer and a vinyl aromatic monomer are copolymerized, the iodine value of the rubbery polymer (A) decreases as the content of the conjugated diene monomer unit decreases, and when the conjugated diene monomer unit is hydrogenated, the iodine value decreases as the hydrogenation rate increases. The iodine value of the rubbery polymer (A) can be controlled within the above-mentioned range by adjusting the polymerization conditions such as the amount of the conjugated diene monomer having an unsaturated bond added, the polymerization time, and the polymerization temperature, and the amount of hydrogen added in the hydrogenation step, the hydrogenation time, and other conditions.

[0013] <Ethylene structure content> The rubbery polymer (A) constituting the rubber composition of this embodiment has an ethylene structure content of 3% by mass or more. When the ethylene structure is 3% by mass or more, the necessary level of fracture properties for a tire rubber is easily exhibited. The ethylene structure is preferably 5% by mass or more, more preferably 30% by mass or more, and even more preferably 40% by mass or more. The ethylene structure is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less. When the ethylene structure is 90% by mass or less, the rubber composition of the present embodiment has excellent rubber elasticity. The ethylene structure in the rubbery polymer (A) includes all ethylene structures obtained by copolymerizing ethylene monomers, ethylene structures obtained by polymerizing conjugated diene monomers and then hydrogenating them, etc. For example, when a 1,4-butadiene unit is hydrogenated, two ethylene structures are obtained, and when a 1,4-isoprene unit is hydrogenated, one propylene structure and one ethylene structure are obtained. The content of the ethylene structure in the rubbery polymer (A) can be measured by the method described in the Examples below, and can be controlled to fall within the above-mentioned range by adjusting the amount of ethylene added, the amount of conjugated diene monomer added, the hydrogenation rate, etc.

[0014] <Vinyl aromatic monomer block content> The rubbery polymer (A) has a vinyl aromatic monomer block content of less than 10% by mass (vinyl aromatic monomer block <10% by mass). The vinyl aromatic monomer block refers to a block in which eight or more vinyl aromatic monomer units are chained. When the vinyl aromatic monomer block content is less than 10% by mass, the rubber composition of this embodiment tends to exhibit good peel resistance, and the rubber composition is excellent in moldability into bale molded articles and cuttability during weighing of the bale molded articles. The vinyl aromatic monomer block content is preferably 7% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less. From the viewpoint of flexibility of the rubber-like polymer or rubber composition, it is preferable that the vinyl aromatic monomer block has few or no blocks in which 30 or more vinyl aromatic monomer units are chained. Specifically, when the polymer constituting the rubbery polymer (A) is a butadiene-styrene copolymer, the content of the vinyl aromatic monomer block can be measured by decomposing the polymer by the Kolthoff method (I.M. Kolthoff, et al., J. Polym. Sci. 1, 429 (1946)) and analyzing the amount of polystyrene insoluble in methanol. Alternatively, it can be measured by a known method, such as measuring the chain of styrene units using NMR, as described in International Publication No. 2014-133097. The vinyl aromatic monomer block content of the rubbery polymer (A) can be controlled within the above range by adjusting the method of adding the vinyl aromatic monomer, the addition of a polymerization aid, the polymerization temperature, etc.

[0015] <Monomer units that allow the rubber polymer (A) to contain an unsaturated group> The rubbery polymer (A) preferably contains 2 mass% or more of conjugated diene monomer units or monomer units having an unsaturated group such as myrcene, etc. From the viewpoints of economy and productivity, it is more preferable that the rubbery polymer (A) contains conjugated diene monomer units. The conjugated diene monomer units and myrcene contained as components of the rubbery polymer (A) have double bonds, and therefore act as crosslinkable unsaturated groups. The content of conjugated diene monomer units and monomer units having an unsaturated group such as myrcene in the rubbery polymer (A) is closely related to the above-mentioned iodine value. When the content of conjugated diene monomer units or monomer units having an unsaturated group such as myrcene is 2% by mass or more, the rubber composition is excellent in terms of ease of crosslinking and adhesion of the bale molded product to the packaging sheet. The content of conjugated diene monomer units is more preferably 3% by mass or more, and even more preferably 6% by mass or more. The content of conjugated diene monomer units and monomer units having an unsaturated group such as myrcene is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less, which provides excellent mechanical strength and abrasion resistance when made into a tire. The content of conjugated diene monomer units and monomer units having an unsaturated group such as myrcene in the rubbery polymer (A) can be measured by the method described in the Examples below, and can be controlled to fall within the above-mentioned range by adjusting the hydrogenation rate described below.

[0016] (Aluminum (B)) The rubber composition of this embodiment has an aluminum (B) content of less than 2 ppm. When the aluminum (B) content is within this range, the rubber composition of this embodiment exhibits the effect of suppressing an increase in viscosity over time. The reason why the viscosity of the rubber composition of this embodiment can be prevented from increasing over time by keeping the concentration of aluminum (B) low is that when the aluminum content in the rubber composition is 2 ppm or more, the finely dispersed aluminum-containing compound interacts with the heteroatoms in the rubber polymer and the residues of the coupling agent, causing an increase in viscosity. Therefore, by keeping the aluminum content below 2 ppm, such an increase in viscosity can be prevented. In particular, when the rubber-like polymer (A) described below has a weight-average molecular weight of 310,000 or more, contains nitrogen atoms, and the nitrogen atoms are likely to become primary amines, or contains a coupling agent having an alkoxysilane, an aluminum content of less than 2 ppm is significantly effective in suppressing an increase in viscosity over time. The content of aluminum (B) is the amount of each element, even if it is contained as a compound containing aluminum. The aluminum content of the rubbery polymer (A) can be measured by the method described in the Examples below, and can be controlled to fall within the above-mentioned range by adjusting the type and amount of polymerization catalyst or hydrogenation catalyst, deashing, or the conditions of the solvent removal step described below.

[0017] (Titanium (C)) The content of titanium (C) in the rubber composition of the present embodiment is 3 ppm or more and 120 ppm or less (3 ppm≦titanium (C) content≦120 ppm). From the viewpoint of the contamination resistance of the molding die when molding the rubber composition, the content is 3 ppm or more, more preferably 10 ppm or more, and even more preferably 15 ppm or more. On the other hand, from the viewpoints of preventing peeling of the rubber composition from the bale molded body, preventing clogging of the mesh with gel components when the viscosity of the rubber composition increases over time, and adhesion of the packaging sheet to the bale molded body, the content is 120 ppm or less, more preferably 100 ppm or less, even more preferably 50 ppm or less, and even more preferably 30 ppm or less. The reason why the presence of titanium (C) can prevent contamination of the molding die is thought to be that the presence of metal particles on the contact surface with the die reduces the adhesion of the polymer to the die, similar to the effect of baby powder. The content of titanium (C) can be controlled within the above range by adjusting the amount of the titanium-containing hydrogenation catalyst added, which will be described later, or the step of removing the solvent from the polymerization solvent.

[0018] (Preferred Structure of Rubber Polymer (A)) <Hydrogenated polymer> The rubbery polymer (A) is preferably a hydrogenated polymer in which some or most of the double bonds in a rubbery polymer obtained by polymerizing or copolymerizing at least conjugated diene monomer units and monomer units having an unsaturated group such as myrcene are hydrogenated (hydrogenated). The unsaturated groups in the rubbery polymer (A) include unsaturated groups derived from conjugated diene monomer units, myrcene, etc. That is, in the process for producing the rubbery polymer (A), when at least conjugated diene monomer units, myrcene, or other monomer units having an unsaturated group are polymerized or copolymerized and then some or most of the double bonds in the polymer are hydrogenated (hydrogenated), it is preferable that the conjugated diene monomer units that remain unhydrogenated are included so as to achieve a predetermined iodine value.

[0019] <Monomers Constituting Rubber Polymer (A)> The rubbery polymer (A) can be formed from a conjugated diene monomer and, if necessary, other monomers. Examples of conjugated diene monomers include, but are not limited to, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1,3-hexadiene, and 1,3-heptadiene. Among these, from the viewpoint of ease of industrial availability, 1,3-butadiene and isoprene are preferred, and 1,3-butadiene is more preferred. These may be used alone or in combination of two or more. The monomer to be used as needed is not particularly limited, but from the viewpoint of mechanical strength when made into a tire, it is preferable to copolymerize a vinyl aromatic monomer. Examples of the vinyl aromatic monomer include, but are not limited to, styrene, p-methylstyrene, α-methylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, diphenylethylene, vinylbenzyldimethylamine, (4-vinylbenzyl)dimethylaminoethyl ether, N,N-dimethylaminoethylstyrene, N,N-dimethylaminomethylstyrene, and tertiary amino group-containing diphenylethylene (e.g., 1-(4-N,N-dimethylaminophenyl)-1-phenylethylene). Among these, styrene is preferred from the viewpoint of industrial availability. These may be used alone or in combination of two or more. As other monomers to be used as required, the following monomers can also be used. Examples include unsaturated carboxylic acid esters, unsaturated carboxylic acids, α,β-unsaturated nitrile compounds, α-olefins (butylene, propylene, butylene, pentene, hexene, etc.), ethylene, myrcene, ethylidene norbornene, isopropylidene norbornene, cyclopentadiene, and divinylbenzene.

[0020] <Amount of vinyl bond in rubber polymer (A)> For the rubbery polymer (A), the vinyl bond content of the conjugated diene monomer units of the conjugated diene polymer before hydrogenation is important, and the vinyl bond content in the conjugated diene monomer units is preferably 10 mol% or more, more preferably 20 mol% or more, from the viewpoints of productivity of the rubbery polymer (A) and high wet skid resistance when made into a tire. Also, from the viewpoint of mechanical strength when used in a tire, it is preferably 75 mol% or less, more preferably 60 mol% or less, even more preferably 45 mol% or less, and even more preferably 30 mol% or less. The vinyl bond content can be measured by the method described in the examples below. The vinyl bond amount can be controlled within the above range by adjusting the polymerization temperature and the amount of polar compound added during polymerization.

[0021] <Step of Polymerizing and Hydrogenating Rubber Polymer (A)> The polymerization step and hydrogenation step for producing the rubbery polymer (A) may each be either a batch process or a continuous process. The hydrogenation rate and the inter- and intra-molecular distribution of monomers such as ethylene, conjugated diene monomers and vinyl aromatic monomers in the rubbery polymer (A) are not particularly limited, and may be uniform, non-uniform, or distributed.

[0022] <Vinyl aromatic monomer unit content> The content of vinyl aromatic monomer units in the rubbery polymer (A) is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and even more preferably 20% by mass or more, from the viewpoints of deformation resistance during transportation of the molded product, and breaking strength and wet skid resistance when used in a tire tread. On the other hand, from the viewpoint of cuttability during measurement of the bale molded body and fuel economy and abrasion resistance when used in a tire tread, the content is preferably 45% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less. In addition, when a high modulus is required, such as in run-flat tire components, the content is preferably 30% by mass or more. The content of the vinyl aromatic monomer units in the rubbery polymer (A) can be measured by the method described in the Examples below, and can be controlled within the above-mentioned range by adjusting the amount of the vinyl aromatic monomer added in the polymerization step.

[0023] <Nitrogen atom> The rubbery polymer (A) preferably contains a nitrogen atom from the viewpoint of the resistance to peeling of the rubber composition from a molded article of the rubber composition and fuel economy when made into a tire. Nitrogen atoms can be incorporated into the rubbery polymer (A) by using, for example, a coupling agent containing a nitrogen atom in the production process of the rubbery polymer (A).

[0024] <Degeneration rate> From the viewpoint of dispersibility of silica when produced into a tire using silica, the rubbery polymer (A) preferably has a modification rate of 40% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, as measured by a column adsorption GPC method. In this specification, the "modification ratio" represents the mass ratio of the polymer having a nitrogen atom-containing functional group to the total amount of the rubbery polymer (A). The position at which the nitrogen atom is introduced into the rubbery polymer (A) may be any of the polymerization initiation terminal of the rubbery polymer (A), in the molecular chain (including the graft product), or at the polymerization terminal.

[0025] From the viewpoints of polymerization productivity, a high modification rate, and wear resistance and fuel economy when made into a tire, it is preferable to introduce nitrogen or tin atoms into the rubbery polymer (A) using a coupling agent containing tin atoms or nitrogen atoms, and it is more preferable to introduce nitrogen atoms into the rubbery polymer (A) using a coupling agent containing nitrogen atoms.

[0026] As the coupling agent containing a nitrogen atom, from the viewpoints of polymerization productivity and a high modification rate, an isocyanate compound, an isothiocyanate compound, an isocyanuric acid derivative, a nitrogen group-containing carbonyl compound, a nitrogen group-containing vinyl compound, a nitrogen group-containing epoxy compound, a nitrogen group-containing alkoxysilane compound, and the like are preferred. As these nitrogen atom-containing coupling agents, nitrogen group-containing alkoxysilane compounds are more preferred from the viewpoints of polymerization productivity of the rubbery polymer (A), a high modification rate, and tensile strength when made into a tire.

[0027] Examples of the nitrogen group-containing alkoxysilane compound include, but are not limited to, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-diethoxy-1-(3-triethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-(4-trimethoxysilylbutyl)-1-aza-2-silacyclohexane, 2,2-dimethoxy-1-(5-trimethoxysilylpentyl)-1-aza-2-silacyclohexane, 2,2-dimethoxy-1-(5-trimethoxysilylpentyl)-1-aza-2-silacyclohexane, 2,2-dimethoxy-1-(5-trimethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-(5-trimethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-(5-trimethoxysilylpropyl)-1-aza-2-silacyclohexane ... )-1-Aza-2-silacycloheptane, 2,2-dimethoxy-1-(3-dimethoxymethylsilylpropyl)-1-aza-2-silacyclopentane, 2,2-diethoxy-1-(3-diethoxyethylsilylpropyl)-1-aza-2-silacyclopentane, 2-methoxy,2-methyl-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane, 2-ethoxy,2-ethyl-1-(3-triethoxysilylpropyl)-1-aza-2-silacyclopentane Clopentane, 2-methoxy, 2-methyl-1-(3-dimethoxymethylsilylpropyl)-1-aza-2-silacyclopentane, and 2-ethoxy, 2-ethyl-1-(3-diethoxyethylsilylpropyl)-1-aza-2-silacyclopentane, tris(3-trimethoxysilylpropyl)amine, tris(3-methyldimethoxysilylpropyl)amine, tris(3-triethoxysilylpropyl)amine, tris(3-methyldiethoxysilylpropyl)amine Amines, tris(trimethoxysilylmethyl)amine, tris(2-trimethoxysilylethyl)amine, and tris(4-trimethoxysilylbutyl)amine, tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane, and N 1 -(3-(bis(3-(trimethoxysilyl)propyl)amino)propyl)-N 1 -methyl-N 3 -(3-(methyl(3-(trimethoxysilyl)propyl)amino)propyl)-N 3-(3-(trimethoxysilyl)propyl)-1,3-propanediamine.

[0028] (Physical Properties of Rubber Polymer (A) and Rubber Composition) <Glass transition temperature> The glass transition temperature of the rubbery polymer (A) is preferably −90° C. or higher, more preferably −80° C. or higher, and even more preferably −75° C. or higher, from the viewpoint of tensile strength when made into a tire. On the other hand, from the viewpoint of the cut resistance of the sheet during tire production and the flexibility of the tire when made into a tire, the temperature is preferably -15°C or lower, more preferably -30°C or lower, and even more preferably -40°C or lower. The glass transition temperature is determined in accordance with ISO 22768:2006 by recording a DSC curve while increasing the temperature within a predetermined temperature range, and the peak top (inflection point) of the DSC differential curve is taken as the glass transition temperature.

[0029] <Weight average molecular weight> The weight average molecular weight of the rubber polymer (A) is preferably 150,000 or more, more preferably 200,000 or more, even more preferably 310,000 or more, and even more preferably 350,000 or more, from the viewpoints of the shape stability of a molded article using the rubber composition of this embodiment and the tensile strength, abrasion resistance, and crack resistance of a crosslinked article using the rubber composition. On the other hand, from the viewpoint of processability when the rubber composition of the present embodiment is made into a rubber composition for crosslinking, the molecular weight is preferably 1,000,000 or less, more preferably 500,000 or less, and even more preferably 400,000 or less. The molecular weight distribution (=weight average molecular weight / number average molecular weight) of the rubbery polymer (A) is preferably 2.0 or less, more preferably 1.8 or less, and even more preferably 1.6 or less, from the viewpoint of fuel economy when the rubber composition is used in a tire. On the other hand, from the viewpoint of processability when the rubber composition is made into a rubber composition for crosslinking, the ratio is preferably 1.05 or more, more preferably 1.2 or more, and even more preferably 1.4 or more. The weight average molecular weight and molecular weight distribution can be calculated from the polystyrene-equivalent molecular weight measured by GC (gel permeation chromatography), and can be measured by the method described in the examples below.

[0030] <Mooney viscosity> The Mooney viscosity of the rubbery polymer (A) and the rubber composition of this embodiment is an index containing information such as the molecular weight, molecular weight distribution, degree of branching, and content of softener of the rubbery polymer (A). The Mooney viscosity of the rubber composition of the present embodiment measured at 100°C is preferably 40 or more, more preferably 50 or more, and even more preferably 55 or more, from the viewpoints of abrasion resistance, handling stability, and breaking strength when the rubber composition for crosslinking is used in a tire. On the other hand, from the viewpoints of productivity of the rubbery polymer (A) and the rubber composition of the present embodiment, and processability when a composition containing a filler or the like is prepared, the molecular weight is preferably 170 or less, more preferably 150 or less, even more preferably 130 or less, and even more preferably 110 or less. The Mooney viscosity can be measured by the method specified in ISO289.

[0031] (Rubber softener (D)) The rubber composition of the present embodiment may contain a rubber softener (D) as needed, and the content of the rubber softener (D) is preferably 30% by mass or less. In the rubber composition of this embodiment, in order to improve the productivity of the rubber polymer (A) and the processability when an inorganic filler or the like is compounded during tire production, the amount of rubber softener (D) added is preferably 1 to 30 mass %. When the molecular weight of the rubber-like polymer (A) is high, for example, when the weight average molecular weight exceeds 1,000,000, it is preferable to add 15 to 30 mass% of the rubber softener (D). On the other hand, when a rubber composition containing a filler is to be prepared, it is preferable to add 1 to 15 mass% of the rubber softener (D) in order to increase the degree of freedom in the compounding. The content of the rubber softener (D) in the rubber composition of the present embodiment is more preferably 20% by mass or less, even more preferably 10% by mass or less, and even more preferably 5% by mass or less, from the viewpoint of suppressing deterioration over time when made into a tire and from the viewpoint of contamination resistance of the molding die.

[0032] The rubber softener (D) is not particularly limited, but examples thereof include extender oil, liquid rubber, and resin. As the rubber softener (D), extender oils are preferred from the viewpoints of processability, productivity and economy. The method of adding the rubber softener (D) to the rubber composition of the present embodiment is not limited to the following, but a preferred method is to add the rubber softener to a polymer solution, mix, and then remove the solvent from the resulting polymer solution containing the rubber softener.

[0033] Preferred extender oils include, but are not limited to, aromatic oils, naphthenic oils, paraffin oils, and the like. Among these, from the viewpoints of environmental safety, oil bleeding prevention, and wet grip properties, aroma substitute oils having a polycyclic aromatic (PCA) content of 3 mass% or less according to the IP346 method are preferred. Examples of aroma substitute oils include TDAE (Treated Distillate Aromatic Extracts), MES (Mild Extraction Solvate), and RAE (Residual Aromatic Extracts), as shown in Kautschuk Gummi Kunststoffe 52(12)799(1999).

[0034] [Method for producing a bale molded product of a rubber composition] The method for producing a bale molded product of the rubber composition of this embodiment includes the steps of polymerizing at least a conjugated diene monomer in a solution to obtain a rubbery polymer (A), adding titanium (C) to the solution containing the obtained rubbery polymer (A) to obtain a rubber composition, and molding the rubber composition. In one preferred embodiment, the polymerization step is a step of polymerizing a conjugated diene and / or a step of copolymerizing a conjugated diene with an aromatic vinyl, and a compound containing titanium (C) functions as a hydrogenation catalyst in a solution containing the (co)polymer, thereby producing the rubbery polymer (A).

[0035] (Method for Polymerizing and Hydrogenating Rubber Polymer (A)) From the viewpoint of the production cost of the rubbery polymer (A) and fuel economy and flexibility when used in a tire, the rubbery polymer (A) is obtained by polymerizing at least a conjugated diene monomer or copolymerizing the conjugated diene monomer with other monomers. It is preferred to hydrogenate (hydrogenate) a part or most of the double bonds in the rubbery polymer (A). The unsaturated groups in the rubbery polymer (A) preferably include conjugated diene monomer units that have been left unhydrogenated so as to achieve a predetermined iodine value.

[0036] As a method of polymerizing or copolymerizing at least a conjugated diene monomer and then hydrogenating it, for example, WO 96 / 05250, JP 2000-053706, WO 2003 / 085010, WO 2019 / 151126, WO 2019 / 151127, WO 2002 / 002663, WO 2015 / 006179, under various additives and conditions, it is preferable to apply a method in which a conjugated diene monomer is polymerized by anionic polymerization, and if necessary, copolymerized with other monomers and then hydrogenated.

[0037] (Titanium (C) in rubber composition) The titanium (C) in the rubber composition of the present embodiment is preferably a catalyst residue obtained during the production of the rubbery polymer (A). In such a case, titanium (C) as a catalyst is preferably a hydrogenation catalyst component. As the hydrogenation catalyst component used in producing the rubbery polymer (A), from the viewpoint of easily adjusting the amount of metal in the rubber composition of this embodiment to a predetermined amount, for example, JP-A-1-275605, JP-A-2-172537, JP-A-4-96904, JP-A-08-33846, JP-A-08-41081, WO 2014-046016, WO 2014-046017, WO 2014-065283, WO 2017-090714, and WO 2017-090714 are preferred. The hydrogenation catalyst component is preferably a mixture or reactant of a Ti compound with a Li compound and / or a Mg compound, and from the viewpoint of the hydrogenation rate, a mixture or reactant of a Ti compound with a Li compound is even more preferable.

[0038] The Ti compound includes titanocene represented by the following formula (1).

[0039] [ka]

[0040] (In the formula (1), R1 and R2 represent a group selected from the group consisting of a C1 to C12 hydrocarbon group, an aryloxy group, an alkoxyl group, a halogen group, and a carbonyl group, and R1 and R2 may be the same or different.)

[0041] From the viewpoint of a high hydrogenation rate, the Ti compound is not limited to the following, but preferred examples include bis(η5-cyclopentadienyl)titanium di(p-tolyl), bis(η5-cyclopentadienyl)titanium di(phenyl), bis(η5-cyclopentadienyl)titanium di(3,4-xylyl), bis(η5-cyclopentadienyl)titanium(furfuryloxy)chloride, and bis(η5-cyclopentadienyl)titanium dichloride. From the viewpoint of economy, bis(η5-cyclopentadienyl)titanium dichloride is more preferred.

[0042] Examples of the Li compound include, but are not limited to, methyllithium, ethyllithium, n-propyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, isobutyllithium, t-butyllithium, n-pentyllithium, n-hexyllithium, phenyllithium, cyclopentadienyllithium, m-tolyllithium, p-tolyllithium, xylyllithium, dimethylaminolithium, diethylaminolithium, methoxylithium, ethoxylithium, n-propoxylithium, isopropoxylithium, n-butoxylithium, sec-butoxylithium, t-butoxylithium, pentyloxylithium, hexyloxylithium, heptyloxylithium, octyloxylithium, phenoxylithium, 4-methylphenoxylithium, benzyloxylithium, and 4-methylbenzyloxylithium.

[0043] Examples of Mg compounds include, but are not limited to, dimethylmagnesium, diethylmagnesium, dibutylmagnesium, ethylbutylmagnesium, methylmagnesium bromide, methylmagnesium chloride, ethylmagnesium bromide, ethylmagnesium chloride, phenylmagnesium bromide, phenylmagnesium chloride, t-butylmagnesium chloride, and t-butylmagnesium bromide.

[0044] (Amount of titanium and aluminum used in the polymer manufacturing process) The amount of titanium (C) added as a hydrogenation catalyst component during production of the rubbery polymer (A) is preferably 150 ppm or less relative to the polymer before hydrogenation. Within this range, the titanium (C) content in the rubber composition of this embodiment can be easily controlled to a range of 3 ppm to 200 ppm. Furthermore, the amount of aluminum (B) added during the production of the rubbery polymer (A) is preferably 6 ppm or less. Within this range, the aluminum (B) content in the rubber composition of this embodiment can be easily controlled to less than 2 ppm. It is more preferable to not actually add aluminum, from the viewpoint of reducing the amount of aluminum (B) residue in the rubber composition of this embodiment. Furthermore, by using lithium or magnesium instead of aluminum, the function of aluminum as a co-catalyst can be complemented. Furthermore, from the viewpoints of suppressing an increase in Mooney viscosity (ML viscosity) and of the ease of handling and safety of the hydrogenation catalyst, the hydrogenation catalyst added during the production of the rubbery polymer (A) preferably contains 0.05 moles or less of aluminum (B) per mole of titanium (C), more preferably 0.04 moles or less of aluminum (B), even more preferably 0.03 moles or less of aluminum (B), and even more preferably does not contain aluminum (B).

[0045] (Amount of metals other than Al and Ti in rubber composition) The content of lithium in the rubber composition of this embodiment as a metal other than aluminum (B) and titanium (C) is preferably 60 ppm or less, more preferably 50 ppm or less, even more preferably 40 ppm or less, and even more preferably 30 ppm or less from the viewpoint of color change resistance of the rubber composition of this embodiment, while from the viewpoint of tensile elongation after crosslinking, it is preferably 2 ppm or more, more preferably 5 ppm or more, and even more preferably 10 ppm or more.

[0046] The above-mentioned contents of titanium (C) and lithium refer to the amounts of the respective elements, even if they are contained as compounds.

[0047] Furthermore, when the titanium (C) in the rubber composition of this embodiment is a residue of a hydrogenation catalyst component or a polymerization catalyst component, the titanium (C) is finely dispersed in the rubber composition and becomes a compound or complex that is difficult to identify, which may have a significant effect on the physical properties of the rubber composition. Therefore, from the viewpoints of not affecting the physical properties of the rubber composition, not complicating the characteristics, and further reducing adhesion of the rubber composition to a mold, it is preferable that the titanium (C) is dispersed in the form of particles in the rubber composition of this embodiment.

[0048] (Addition of additives) When producing the rubber composition of this embodiment, it is preferable to add a deactivator, neutralizer, etc. after the polymerization step of the rubbery polymer (A) in order to easily adjust the amount of metal in the rubber composition of this embodiment to a predetermined range. The quenching agent is not limited to the following, but examples thereof include water; and alcohols such as methanol, ethanol, and isopropanol. Examples of neutralizing agents include, but are not limited to, carboxylic acids such as stearic acid, oleic acid, and versatic acid (a highly branched carboxylic acid mixture having 9 to 11 carbon atoms, mainly 10 carbon atoms); aqueous solutions of inorganic acids; and carbon dioxide gas. After the polymerization step of the rubbery polymer (A), it is preferable to add a rubber stabilizer from the viewpoint of preventing gel formation and improving processing stability. The rubber stabilizer is not limited to the following and any known stabilizer can be used. Preferred examples include antioxidants such as 2,6-di-tert-butyl-4-hydroxytoluene (hereinafter also referred to as "BHT"), n-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenol) propionate, and 2-methyl-4,6-bis[(octylthio)methyl]phenol.

[0049] Various additives may be added to the rubber composition of the present embodiment as needed. Such additives include fillers or resin components serving as tackifiers, as described below, which may be added as masterbatches in a process prior to molding. In this case, the amount of the additives is preferably 15% by mass or less. In the rubber composition of this embodiment, from the viewpoint of improving the balance between the handleability and mechanical strength of the rubber composition, and the fuel economy and abrasion resistance when used in a tire, the content of the rubber polymer (A) + aluminum (B) + titanium (C) + rubber softener (D) is preferably 85% by mass or more, more preferably 95% by mass or more, and even more preferably 97% by mass or more.

[0050] When producing the rubber composition of this embodiment, after carrying out the step of polymerizing the rubbery polymer (A) in a solution, the solvent is removed from the polymer solution. Examples of methods for removing the solvent from the polymer solution include flushing, steam stripping, methods using a drying conveyor after dehydration, a devolatilizing extruder, a drum dryer, and a devolatilizing kneader. From the viewpoint of small thermal history and easy adjustment of the metal content in the rubber composition to a desired level, at least the method using steam stripping is preferred. In particular, since it is difficult to adjust the metal content of the rubber polymer (A) using a coupling agent containing a nitrogen atom, the method using steam stripping is useful from the viewpoint of adjusting the metal content. Steam stripping and treatment methods before and after it are not limited to the following, but include, for example, methods described in JP-A-10-168101, JP-A-10-204136, WO 2013-146530, JP-A-2019-131810, etc. Examples include methods.

[0051] In the method for producing the rubber composition of this embodiment, it is preferable to carry out a solvent removal step in which the solvent is removed from the polymer solution by steam stripping, and a screening step in which the stripping water is separated from the polymer slurry and water-containing crumbs are extracted, as a step prior to carrying out the extrusion drying step. Furthermore, a flashing step may be performed prior to steam stripping to increase the solution concentration. As a preliminary step to the extrusion drying step, a desolvation step is carried out in which the solvent is removed from the polymer solution by steam stripping, thereby obtaining a solvent-free slurry in which porous granular crumbs containing moisture are dispersed in hot water. By carrying out a screening step in which the stripping water is separated from the polymer slurry and the wet crumbs are taken out, porous granular crumbs containing water can be obtained. If necessary, it is preferable to carry out a squeezing and dehydrating step in which water is removed using a roll, a screw compression squeezer, etc. By using these dehydrating steps, it is possible to obtain hydrous crumbs with a lower moisture content prior to the extrusion drying step.

[0052] Examples of a method for controlling the content of titanium (C) in the rubber composition of this embodiment to 3 ppm or more and 120 ppm or less by steam stripping include, as conditions for contacting the solution of the rubbery polymer (A) after polymerization with hot water or steam, adjusting the solution introduction pressure, adjusting the pressure, temperature, or amount of steam, adding a dispersant such as a phosphate ester or a salt thereof, e.g., polyoxyalkylene alkyl ether phosphate, or a surfactant such as a nonylphenoxy polyethylene glycol phosphate ester or a salt thereof, to the steam, and adjusting the shape or rotation speed of the rotor used during mixing.

[0053] When producing the rubber composition of this embodiment, for reasons of economy and metal removability, it is preferable to add an alcohol compound as a deactivator to the polymer solution, and it is more preferable to add in advance a dispersant or a surfactant that is added during steam stripping.

[0054] Methods for reducing the titanium (C) content in the rubber composition of this embodiment include, for example, adding an alcohol compound as a deactivator to the polymer solution after polymerization of the rubber polymer (A) in an amount of 0.5 times or more, preferably 1.0 times or more, by mole, the number of moles of the rubber polymer (A); setting the steam / polymer solution volume ratio in the steam stripping step to 0.1 or more, preferably 0.2 or more; lowering the treatment rate; and adding a surfactant to the polymer solution in an amount of 100 ppm or more, preferably 200 ppm, relative to the polymer.

[0055] The linear speed of the rotor in the steam stripping step is preferably 5 m / s or more and 20 m / s or less, and more preferably 10 m / s or more and 20 m / s or less.

[0056] After the steam stripping, it is preferable to carry out a method in which the rubber composition is extruded, dried, and then dried with hot air, as described in WO 2013-146530. These allow a porous, granular crumb to be obtained. From the viewpoint of a balance between the resistance to contamination of the molding die, the resistance to peeling of the rubber composition from the bale molded body, and the smoothness when the rubber composition for crosslinking is made into a sheet, it is preferable that 60 vol% or more of the particle diameter of the metal or metal compound in the rubber composition is 0.1 to 90 μm, and more preferably 80 vol% or more of the total volume of the metal or metal compound particles is in the above particle diameter range, out of 100 vol%. The particle size of metal or metal compound particles in a rubber composition can be measured by dissolving a rubber composition containing a metal or metal compound in an inert solvent and analyzing the resulting polymer solution with a laser diffraction particle size distribution analyzer. The particle size of the crumbs is preferably 0.1 mm or more, and more preferably 0.5 mm or more, from the viewpoint of obtaining resistance to detachment of the rubber composition from the molded article and resistance to scattering during drying. On the other hand, from the viewpoint of drying the remaining solvent and water in the crumbs and the expansion resistance of the molded article after molding of the rubber composition, the particle size of the crumbs is preferably 30 mm or less, more preferably 20 mm or less. The particle size of the crumbs can be adjusted by either removing the solvent and drying the crumbs, or by processing the crumbs after production. When adjusting the process of removing the solvent and drying the crumbs, there are no particular limitations, but examples include a method of adjusting the molecular weight, composition, or structure of the rubbery polymer (A), a method of adjusting the amount of rubber softener (D) added to a solution of the rubbery polymer (A), a method of adjusting the hole diameter of the die of the extrusion dryer, and a method of adjusting the conditions when the solution of the rubbery polymer (A) is poured into hot water to remove the solvent. When the produced crumbs are processed and adjusted, there are no particular limitations on the method, but examples include a method of sieving the crumbs, and a method of crushing and pulverizing the crumbs with a mixer or granulator.

[0057] The specific surface area of the crumb of the rubber composition of the present embodiment is preferably 0.7 to 3.2 m from the viewpoint of handleability. 2 / g, more preferably 1.0 to 3.0m 2 / g. The specific surface area of the crumb is 0.7m 2 When the specific surface area of the crumb is 3.2 m / g or more, the area where one crumb adheres to the surrounding crumbs increases during molding, making it difficult for the crumb to peel off from the molded body. 2 If the density is 0.1g or less, the crumb particles are compressed more densely when molded, and voids between the crumbs are also reduced, so that expansion of the molded body can be suppressed. The method for adjusting the specific surface area of the crumbs to fall within the above range is not particularly limited, but for example, a method of sieving the crumbs and adjusting the composition of each sieved crumb can be mentioned.

[0058] The residual solvent content in the rubber composition of this embodiment is preferably low from the viewpoint of reducing odor and VOCs. It is preferably 5000 ppm or less, more preferably 3000 ppm or less, and even more preferably 1500 ppm or less. Furthermore, from the viewpoint of economical balance, it is preferably 50 ppm or more, more preferably 150 ppm or more, and even more preferably 300 ppm or more.

[0059] (Water content in rubber composition of bale molded body) The water content in the rubber composition of the bale molded article of this embodiment is preferably 0.05% by mass or more and 1.5% by mass or less. The water content in the rubber composition is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.2% by mass or more, from the viewpoints of suppressing gel formation during drying after solvent removal and suppressing a decrease in yield due to the generation of powder, while the water content is preferably 1.5% by mass or less, more preferably 1.0% by mass or less, and even more preferably 0.8% by mass or less, from the viewpoint of suppressing condensation in the rubber composition. The water content in the rubber composition of the bale molded article of this embodiment can be controlled within the above-mentioned range by adjusting the crumb shape and the conditions of the drying process.

[0060] [Molded body] The bale molded article of this embodiment is a molded article of the rubber composition of this embodiment described above, and is preferably a block-shaped molded article from the viewpoint of handleability. The bale molded body of this embodiment is 1,000 cm 3 The above-mentioned block-shaped (bale) molded bodies are more preferred, and rectangular parallelepiped bale molded bodies weighing 17.5 kg to 35 kg are even more preferred.

[0061] The bale molding method of this embodiment includes a method of compressing crumbs and a method of preparing sheets and then stacking and compressing them. 2 / g~3.2m 2 In view of moldability, it is preferable to further carry out a step of sieving the crumbs before molding. Since the crumbs adhere to each other when they are compression molded, the specific surface area of the molded product is lower than that of the crumbs. The adhesion of the crumbs during compression molding can be adjusted by the molecular weight, composition, and structure of the rubber polymer (A), the rubber softener composition, and the temperature and pressure during compression. For example, if you want to increase the adhesion of the crumbs and decrease the specific surface area of the bale, it is preferable to reduce the molecular weight of the rubber polymer (A), increase the amount of the rubber softener, and increase the temperature and pressure during compression.

[0062] The specific surface area of the bale molded body of this embodiment is preferably 0.005 to 0.05 m 2 / g, and more preferably, 0.01 to 0.04 m from the viewpoint of film packaging properties. 2 / g. The specific surface area of the bale compact is 0.005m 2 / g or more, the expansion of the bale is suppressed, and the specific surface area of the bale compact is 0.05m 2 / g or less is preferable because it reduces the separation of crumbs from the bale molded body. The specific surface area of the bale molded body can be determined by the BET method. Generally, the specific surface area of a large sized bale tends to vary depending on the position, so it is preferable to collect the bale from near the center.

[0063] The rubber composition crumbs of this embodiment are preferably sieved according to particle size before being molded into a bale molded article, and then mixed in an appropriate ratio. If the specific surface area of the bale formed using the crumbs after solvent removal exceeds the upper limit of the above range, it is preferable to increase the composition of large crumbs and decrease the composition of small crumbs among the sieved crumbs, and if it is below the lower limit, it is preferable to decrease the composition of large crumbs and increase the composition of small crumbs.

[0064] The molding compression pressure for the bale molded body of this embodiment is preferably 3 to 30 MPa, more preferably 10 to 20 MPa. When the molding compression pressure is 30 MPa or less, the device can be designed compactly, and installation efficiency is good. When the molding compression pressure is 3 MPa or more, moldability is good. When moldability is good, the surface of the bale molded body is smooth, there is no polymer peeling after the molding process, and expansion after molding tends to be suppressed.

[0065] The temperature of the rubber composition during molding is preferably 30 to 120°C, and more preferably 50 to 100°C from the viewpoint of reducing residual solvent and suppressing thermal degradation. When the temperature of the rubber composition during molding is 30°C or higher, moldability is good, while when the temperature is 120°C or lower, gel formation due to thermal degradation of the rubber composition is suppressed, which is preferable. The higher the temperature and pressure during molding, the smaller the specific surface area of the bale molded body. The pressure retention time during molding is preferably 3 to 30 seconds, more preferably 5 to 20 seconds. When the pressure retention time during compression is 30 seconds or less, production efficiency is good, and when it is 5 seconds or more, moldability is good.

[0066] In order to prevent the bale molded bodies from sticking together, the bale molded bodies of this embodiment are preferably wrapped in a resin film (wrapping sheet). The type of resin that can be used for the film includes, for example, polyethylene, ethylene copolymer resin, polystyrene, high impact polystyrene, and PET. From the viewpoint of ease of handling during transportation of the formed body and preventing condensation from forming in the gap between the packaging sheet and the formed bale, it is preferable that the packaging sheet adheres well to the formed bale. The bale molded article of this embodiment is used, for example, for storage in a container for transportation. If the expansion rate of the bale molded article one day after molding is less than 5%, it is preferable because it can be easily stored in the container.

[0067] [Rubber composition for crosslinking] From the viewpoint of high mechanical strength, etc., it is preferable that a crosslinking agent be added to the rubber composition of the bale molded article of this embodiment to form a crosslinkable rubber composition, which is then crosslinked to form a crosslinked article and used for various purposes. The rubber composition for crosslinking of this embodiment contains at least the rubber composition of this embodiment described above and a crosslinking agent, and may further contain other rubber components, fillers, and the like, as necessary. The other rubber components are not particularly limited and can be appropriately selected depending on the purpose. Examples include styrene-butadiene rubber (emulsion polymerization tire or solution polymerization type), natural rubber, polyisoprene, butadiene rubber, acrylonitrile-butadiene rubber (NBR), chloroprene rubber, ethylene-propylene rubber (EPM), ethylene-propylene-non-conjugated diene rubber (EPDM), butyl rubber, polysulfide rubber, silicone rubber, fluororubber, and urethane rubber. These may be used alone or in combination of two or more.

[0068] In the rubber composition for crosslinking of this embodiment, the content of the rubber-like polymer (A) relative to the total amount of rubber, which is the sum of the rubber-like polymer (A) and other rubber components, is preferably 20% by mass or more, more preferably 40% by mass or more, even more preferably 60% by mass or more, and even more preferably 80% by mass or more, from the viewpoint of exerting the effects of the present invention.

[0069] Furthermore, in the rubber composition for crosslinking of the present embodiment, a filler can be added as needed for the purpose of improving reinforcement properties, etc. The amount of filler to be added is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 10 to 100 parts by mass, more preferably 20 to 80 parts by mass, per 100 parts by mass of the rubber component, which is the total of the rubber-like polymer (A) and other rubbers. When the amount of filler is 10 parts by mass or more, the effect of improving reinforcing properties due to the addition of filler can be obtained, and when the amount is 100 parts by mass or less, good workability can be maintained while avoiding a significant decrease in fuel efficiency when made into a tire.

[0070] The filler is not particularly limited and examples thereof include carbon black, silica, aluminum hydroxide, clay, alumina, talc, mica, kaolin, glass balloons, glass beads, calcium carbonate, magnesium carbonate, magnesium hydroxide, magnesium oxide, titanium oxide, potassium titanate, barium sulfate, etc. Among these, carbon black is preferably used. These may be used alone or in combination of two or more. The carbon black is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include FEF, GPF, SRF, HAF, N339, IISAF, ISAF, SAF, etc. These may be used alone or in combination of two or more. The nitrogen adsorption specific surface area (N2SA, measured in accordance with JIS K6217-2:2001) of the carbon black is not particularly limited and can be appropriately selected depending on the purpose. When the rubber composition for crosslinking of the present embodiment is used as a composition for a fuel-saving tire tread, precipitated silica is preferably used as the filler.

[0071] The rubber composition for crosslinking of the present embodiment may contain a silane coupling agent from the viewpoint of improving the dispersibility of the filler and improving the tensile strength of the crosslinked product. The silane coupling agent has the function of strengthening the interaction between the rubber component and the inorganic filler, and has groups that have affinity or bonding properties for both the rubber component and the silica-based inorganic filler. Preferably, the silane coupling agent is a compound that has a sulfur-bonding moiety and an alkoxysilyl group or silanol group moiety in one molecule. Such compounds include, but are not limited to, bis-[3-(triethoxysilyl)-propyl]-tetrasulfide, bis-[3-(triethoxysilyl)-propyl]-disulfide, bis-[2-(triethoxysilyl)-ethyl]-tetrasulfide, S-[3-(triethoxysilyl)-propyl]octanethioate and condensates of S-[3-(triethoxysilyl)-propyl]octanethioate with [(triethoxysilyl)-propyl]thiol, silanes bearing at least one thiol (—SH) functional group (referred to as mercaptosilanes) and / or at least one masked thiol group. The content of the silane coupling agent in the rubber composition for crosslinking of this embodiment is preferably 0.1 parts by mass or more and 30 parts by mass or less, more preferably 0.5 parts by mass or more and 20 parts by mass or less, and even more preferably 1.0 parts by mass or more and 15 parts by mass or less, relative to 100 parts by mass of the filler. When the content of the silane coupling agent is within the above range, the effect of adding the silane coupling agent tends to be more pronounced.

[0072] The rubber composition for crosslinking of the present embodiment contains a crosslinking agent. The crosslinking agent is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include sulfur-based crosslinking agents, organic peroxide-based crosslinking agents, inorganic crosslinking agents, polyamine crosslinking agents, resin crosslinking agents, sulfur compound-based crosslinking agents, and oxime-nitrosamine-based crosslinking agents, and these may be used in combination. Among these, sulfur-based crosslinking agents (vulcanizing agents) are more preferable for rubber compositions for tires, and sulfur is particularly preferable.

[0073] The content of the crosslinking agent in the rubber composition for crosslinking of this embodiment is 0.1 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the rubber component. From the viewpoint of high tensile strength and a high crosslinking rate, the content of the crosslinking agent is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 1.5 parts by mass or more per 100 parts by mass of the rubber component. On the other hand, from the viewpoint of suppressing uneven crosslinking and high tensile strength, the content is preferably 20 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less. The rubber component includes the above-mentioned rubbery polymer (A) and other rubber components.

[0074] In the rubber composition for crosslinking of the present embodiment, a vulcanization accelerator may be used in addition to the vulcanizing agent. Examples of the vulcanization accelerator include guanidine-based, aldehyde amine-based, aldehyde ammonia-based, thiazole-based, sulfenamide-based, thiourea-based, thiuram-based, dithiocarbamate-based, and xanthate-based compounds.

[0075] In addition, the cross-linkable rubber composition of the present embodiment may contain various additives other than the above-mentioned components, such as other softeners, fillers, heat stabilizers, antistatic agents, weather stabilizers, antioxidants, colorants, and lubricants. As other softeners, known softeners can be used. Other fillers include, for example, calcium carbonate, magnesium carbonate, aluminum sulfate, and barium sulfate. Known materials can be used as the heat stabilizer, antistatic agent, weather stabilizer, antioxidant, colorant, and lubricant.

[0076] (Method of kneading rubber composition for crosslinking) The rubber composition for crosslinking of this embodiment can be produced by mixing the rubber composition of this embodiment described above, a crosslinking agent, and further, as necessary, various additives such as a silica-based inorganic filler, carbon black or other fillers, a silane coupling agent, and a rubber softener. The mixing method is not limited to the following methods, but examples thereof include a melt-kneading method using a general mixer such as an open roll, a Banbury mixer, a kneader, a single-screw extruder, a twin-screw extruder, or a multi-screw extruder, and a method in which the components are dissolved and mixed and then the solvent is removed by heating. Among these, the melt kneading method using a roll, a Banbury mixer, a kneader or an extruder is preferred from the viewpoint of productivity and good kneading properties. In addition, it is possible to use either a method in which the rubber component, other fillers, silane coupling agent, and additives are kneaded at once, or a method in which they are mixed in several batches.

[0077] [Uses of rubber composition and molded article] The rubber composition and the rubber composition for crosslinking according to the present embodiment can be used for, for example, tire components, interior and exterior parts of automobiles, vibration-proof rubber, belts, footwear, foams, various industrial products, and the like. Among these, it is preferably used for tire parts. As tire components, the composition can be used in various tire parts such as treads, carcasses, sidewalls, beads, etc., for example, fuel-efficient tires, all-season tires, high-performance tires, snow tires, studless tires, etc. In particular, as tire components, the composition has an excellent balance of abrasion resistance, fuel economy, wet skid resistance, and snow performance when vulcanized, and is therefore suitably used for tire treads for fuel-efficient tires, high-performance tires, and snow tires. A conventional method can be used to manufacture a tire. For example, components typically used in tire manufacturing, such as a carcass layer, a belt layer, and a tread layer, each layer consisting of at least one selected from the group consisting of an unvulcanized rubber composition for crosslinking and a tire cord, are laminated on a tire building drum, and the drum is removed to form a green tire. The green tire is then heated and vulcanized in a conventional manner to manufacture a desired tire (e.g., a pneumatic tire). [Example]

[0078] Hereinafter, the present embodiment will be described in more detail with reference to specific examples and comparative examples, but the present embodiment is not limited to the following examples and comparative examples. Various physical properties in the examples and comparative examples were measured by the methods shown below.

[0079] [Physical properties of rubber polymer (A)] (Weight average molecular weight (Mw) of rubbery polymer (A) before hydrogenation) The chromatogram was measured using a GPC measuring device equipped with three connected columns packed with polystyrene gel, and the weight average molecular weight (Mw) of the rubbery polymer before hydrogenation was determined based on a calibration curve using standard polystyrene. The eluent used was tetrahydrofuran (THF) containing 5 mmol / L triethylamine. The columns used were a guard column manufactured by Tosoh Corporation under the trade name "TSKguardcolumn SuperH-H" and columns manufactured by Tosoh Corporation under the trade names "TSKgel SuperH5000," "TSKgel SuperH6000," and "TSKgel SuperH7000." An RI detector (trade name "HLC8020" manufactured by Tosoh Corporation) was used under the conditions of an oven temperature of 40°C and a THF flow rate of 0.6 mL / min. 10 mg of the sample to be measured was dissolved in 20 mL of THF to prepare a measurement solution, and 20 μL of the measurement solution was injected into the GPC measurement device for measurement.

[0080] (Polymer Mooney Viscosity of Rubber Polymer (A) Before Hydrogenation) The rubber-like polymer before hydrogenation was used as a sample, and the Mooney viscosity was measured in accordance with ISO 289 using a Mooney viscometer (trade name "VR1132" manufactured by Ueshima Seisakusho Co., Ltd.) with an L-shaped rotor. The measurement temperature was 100°C. First, the sample was preheated at the test temperature for 1 minute, and then the rotor was rotated at 2 rpm. After 4 minutes, the torque was measured to determine the Mooney viscosity (ML (1+4) ) was decided.

[0081] (Modification rate of rubber polymer (A)) The modification rate of the rubbery polymer (A) was measured by the column adsorption GPC method as follows: The measurement was carried out by utilizing the property of the rubbery polymer modified with a nitrogen atom-containing functional group to be adsorbed onto a column. A sample solution containing a rubber-like polymer and a low-molecular-weight internal standard polystyrene was measured using a polystyrene-based column, and the amount of adsorption onto the silica-based column was measured from the difference between the chromatogram measured using the polystyrene-based column and the chromatogram measured using the silica-based column, and the modification rate was calculated. Specifically, it is as follows: Preparation of sample solution: 10 mg of the rubber polymer and 5 mg of standard polystyrene were dissolved in 20 mL of THF to prepare a sample solution. GPC measurement conditions using a polystyrene column: THF containing 5 mmol / L triethylamine was used as the eluent, and 20 μL of the sample solution was injected into the instrument for measurement. The guard column used was a Tosoh Corporation "TSKguardcolumn SuperH-H" (trade name), and columns were Tosoh Corporation "TSKgel SuperH5000," "TSKgel SuperH6000," and "TSKgel SuperH7000" (trade names). The column oven temperature was 40°C, and the THF flow rate was 0.6 mL / min. A chromatogram was obtained using an RI detector (Tosoh Corporation HLC8020). GPC measurement conditions using a silica column: A Tosoh HLC-8320GPC column was used, and 50 μL of the sample solution was injected into the column using THF as the eluent. Chromatograms were obtained using an RI detector at a column oven temperature of 40°C and a THF flow rate of 0.5 mL / min. Zorbax PSM-1000S, PSM-300S, and PSM-60S columns were used, with a DIOL 4.6 x 12.5 mm 5 micron guard column connected to the column. How to calculate the denaturation rate: The total peak area of the chromatogram using the polystyrene column was set to 100, the peak area of the sample was set to P1, the peak area of the standard polystyrene was set to P2, and the total peak area of the chromatogram using the silica column was set to 100, the peak area of the sample was set to P3, and the peak area of the standard polystyrene was set to P4. The modification rate (%) was calculated using the following formula. Denaturation rate (%) = [1-(P2 x P3) / (P1 x P4)] x 100 (However, P1+P2=P3+P4=100)

[0082] (Bound styrene content of rubber polymer (A) before hydrogenation) As a sample, 100 mg of rubber-like polymer before hydrogenation was dissolved in chloroform to make a measuring sample. The amount of bound styrene (mass%) relative to 100 mass% of the rubber-like polymer before hydrogenation was measured based on the amount of absorption of ultraviolet light by the phenyl group of styrene (near 254 nm). Measurement equipment: A spectrophotometer "UV-2450" manufactured by Shimadzu Corporation was used.

[0083] (Microstructure of butadiene portion of rubbery polymer (A) before hydrogenation (1,2-vinyl bond content)) As a sample, 50 mg of the rubber-like polymer before hydrogenation was dissolved in 10 mL of carbon disulfide to prepare a measurement sample. Using a solution cell, infrared spectra were recorded from 600 to 1000 cm -1 The absorbance at a predetermined wave number was measured in the range of 1,2-vinyl bond content (mol%) was calculated according to the Hampton method (method described in R.R. Hampton, Analytical Chemistry 21, 923 (1949)). Measurement equipment: A Fourier transform infrared spectrophotometer "FT-IR230" manufactured by JASCO Corporation was used.

[0084] (Amount of styrene block in rubber polymer (A)) A chain consisting of eight or more styrene structural units was defined as a styrene block, and the block size was determined as follows: 400MHz measured using deuterated chloroform as a solvent 1 From the 1 H-NMR spectrum, the integral value ratio of each chemical shift range of the following (a) was determined, and the content of styrene blocks contained in the rubbery polymer was calculated. (a) Aromatic vinyl compounds with 8 or more chains: 6.00≦S<6.68

[0085] (Iodine value of rubber polymer (A)) The iodine value of the rubbery polymer (A) was calculated according to the method described in "JIS K 0070:1992".

[0086] (Bound styrene amount (after hydrogenation) of rubber-like polymer (A), ethylene structure, conjugated diene monomer unit) Using the rubber polymer (A) as a sample, 1 The amount of bound styrene (after hydrogenation), ethylene structure, and amount of conjugated diene monomer units were measured by H-NMR. 1 The conditions for H-NMR measurement are as follows: <Measurement conditions> Measuring equipment: JNM-LA400 (JEOL) Solvent: deuterated chloroform Measurement sample: Rubber-like polymer Sample concentration: 50mg / mL Observation frequency: 400MHz Chemical shift standard: TMS (tetramethylsilane) Pulse delay: 2.904 seconds Number of scans: 64 Pulse width: 45° Measurement temperature: 26℃

[0087] [Physical Properties of Rubber Composition] (Metal content of rubber composition (Al content, Ti content)) The rubber compositions obtained in the examples and comparative examples described below were subjected to elemental analysis using an inductively coupled plasma (ICP, manufactured by Shimadzu Corporation, device name: ICPS-7510) to measure the aluminum content (Al content, unit: ppm) and titanium content (Ti content, unit: ppm) in the rubber compositions.

[0088] (Water content of rubber composition) 50 g of the rubber composition was placed in a hot air dryer heated to 150° C. and dried for 3 hours, and the difference in mass of the rubber composition before and after drying was measured to determine the moisture content of the rubber composition.

[0089] [Evaluation of molded articles of rubber compositions] (Method for removing solvent from rubber composition solution) <Solvent removal condition 1> Assuming steam stripping, 20 L of 90°C hot water was placed in a 50 L container, and the polymer solution was added dropwise at a rate of 200 g per minute for 30 minutes while stirring at a rotation speed of 1000 rpm using a homogenizer (Homomixer MARKII (PRIMIX Corporation, trade name, 0.2 kW)). After the end of the dropwise addition, stirring was continued for 30 minutes to remove the solvent. Crumbs of the rubber composition formed in the hot water were dried to obtain crumbs of the rubber composition.

[0090] <Solvent removal condition 2> Assuming steam stripping, 20 L of 90°C hot water was placed in a 50 L container, and the polymer solution was added dropwise at a rate of 200 g per minute for 30 minutes while stirring at a rotation speed of 12,000 rpm using a homogenizer (Homomixer MARK II (PRIMIX Corporation, trade name, 0.2 kW)). Stirring was continued for 30 minutes even after the end of the dropwise addition to remove the solvent. Crumbs of the rubber composition formed in the hot water were dried to obtain crumbs of the rubber composition.

[0091] (Method for molding a rubber composition bale) The crumbs prepared by the above method were heated to 60°C and then filled into a rectangular container with dimensions of 210 mm long, 105 mm short, and 200 mm deep, and compressed with a cylinder at a pressure of 3.5 MPa for 10 seconds to obtain a bale of rubber composition.

[0092] (Evaluation: Resistance to Mooney viscosity increase of rubber composition) The Mooney viscosity of the rubber composition was measured under the following conditions. The Mooney viscosity was measured using a Mooney viscometer (trade name "VR1132" manufactured by Ueshima Seisakusho Co., Ltd.) in accordance with ISO 289 using an L-shaped rotor. The measurement temperature was 100°C. First, the sample was preheated at the test temperature for 1 minute, and then the rotor was rotated at 2 rpm. After 4 minutes, the torque was measured to determine the Mooney viscosity (ML (1+4) ) was decided. The difference between the Mooney viscosity measured within 4 hours after the rubber composition was obtained and the Mooney viscosity measured after storage at 25°C and 30% humidity for 1 month was evaluated as ΔML. If ΔML was 0 or more and less than 4, it was marked with a ◎; if it was 4 or more and less than 8, it was marked with a ◯; if it was 8 or more and less than 15, it was marked with a △; and if it was 15 or more, it was marked with an ×. In practice, it is necessary that the ratio is less than 15, and preferably less than 8.

[0093] (Evaluation: Contamination resistance of molding mold) When 10 bale moldings were performed under the above conditions, the number of times that a total of 5 g or more of metal or crumb adhered to the rectangular container was evaluated. If the number of times that a total of 5 g or more of metal or crumb adhered was 0, it was evaluated as ⊚, if it was 1 to 2 times, it was evaluated as ○, if it was 3 to 4 times, it was evaluated as △, and if it was 5 times or more, it was evaluated as ×. In practice, it is necessary that the number of times be 4 or less, and preferably 2 or less.

[0094] (Evaluation: Peel resistance of rubber composition from bale molded body) Using the bale molded under the above conditions, the amount of crumbs that peeled off from the bale molded was determined by a bale drop test. Specifically, the bale was dropped vertically from a height of 100 cm onto a concrete floor, and the amount of crumbs that peeled off from the bale was measured. The smaller the amount of crumbs that peel off, the smaller the amount of crumbs that peel off from the bale molded body after the molding step in the actual manufacturing process, so this is preferable. If this amount was less than 0.05% by mass of the total bale molded body, it was marked with an ⊚; if it was 0.05% by mass or more but less than 0.1% by mass, it was marked with an ◯; if it was 0.01% by mass or more but less than 0.2% by mass, it was marked with a △; and if it was 0.2% by mass or more, it was marked with an ×. In practice, it must be less than 0.2% by mass, and preferably less than 0.1% by mass.

[0095] (Evaluation: Adhesion of bale molded body to packaging sheet) A polyethylene film was adhered to an iron plate, and the bale molded body was placed on the polyethylene film. After leaving it for 72 hours at an ambient temperature of 25°C and humidity of 50% with a load of 5 kg applied, the adhesion between the polyethylene film and the bale molded body was evaluated. Specifically, the bale molded body was left standing on the iron plate, and the iron plate was gradually tilted until the angle between the iron plate and the ground was finally 90 degrees, and the plate was left standing in that state. If the bale did not fall for 10 seconds or more when the angle between the ground and the iron plate was 90 degrees, it was marked as ◎; if the bale fell for 1 second or more but less than 10 seconds when the angle between the ground and the iron plate was 90 degrees, it was marked as 〇; if the bale fell when the angle between the ground and the iron plate was 75 degrees or more but less than 90 degrees, or if it fell in less than 1 second after the angle became 90 degrees, it was marked as △; if the bale fell when the angle between the ground and the iron plate was 0 degrees or more but less than 75 degrees, it was marked as ×. In practice, it is necessary that the angle between the ground and the steel plate be 75 degrees or more so that the bale does not fall.

[0096] [Preparation of hydrogenation catalyst, rubbery polymer (A), and rubber composition] (Preparation of hydrogenation catalyst) In the examples and comparative examples described later, the hydrogenation catalysts used in preparing rubbery polymers were prepared by the following method. <Production Example 1> Two liters of dried and purified cyclohexane was placed in a nitrogen-purged reactor, and 40 mmol of bis(η5-cyclopentadienyl)titanium di-(p-tolyl) and 150 g of 1,2-polybutadiene (1,2-vinyl bond content: approximately 85%) with a molecular weight of approximately 1,000 were dissolved therein. A cyclohexane solution containing 60 mmol of n-butyllithium was then added to the reactor, and the mixture was allowed to react at room temperature for 5 minutes. 40 mmol of n-butanol was immediately added and stirred to obtain the hydrogenation catalyst (TC-1). The resulting catalyst was stored at room temperature.

[0097] <Production Example 2> One liter of dried and purified cyclohexane was placed in a nitrogen-purged reaction vessel, and 100 mmol of bis(η5-cyclopentadienyl)titanium dichloride was added. With thorough stirring, an n-hexane solution containing 200 mmol of trimethylaluminum was added, and the mixture was allowed to react at room temperature for approximately 3 days to obtain a hydrogenation catalyst (TC-2).

[0098] (Polymerization of rubbery polymer (A)) <(Polymerization Example 1) Rubber-like polymer (S) before hydrogenation> A 40 L internal volume, temperature-controllable autoclave equipped with a stirrer and a jacket was used as a reactor, and 2,160 g of 1,3-butadiene, 300 g of styrene, 21,000 g of cyclohexane, and 30 mmol of tetrahydrofuran (THF) and 3.6 mmol of 2,2-bis(2-oxolanyl)propane as polar substances, which had been previously removed from impurities, were placed in the reactor, and the internal temperature of the reactor was maintained at 46°C. As a polymerization initiator, 23.9 mmol of n-butyllithium was fed into the reactor. After the polymerization reaction started, the temperature inside the reactor began to rise due to heat generated by the polymerization, and after the monomer conversion in the reactor reached 98%, 540 g of 1,3-butadiene was added and reacted. The final temperature inside the reactor reached 76°C. Two minutes after this reaction temperature peak, 9.0 mmol of N-benzylidene-3-(trimethoxysilyl)-1-propanamine (Compound 1) was added to the reactor, and the coupling reaction was carried out for 20 minutes. 5.5 mmol of methanol was added to this polymer solution as a reaction terminator to obtain a rubbery polymer solution (SS). A portion of the rubbery polymer solution before hydrogenation was withdrawn and the solvent was removed in a dryer to obtain a rubbery polymer (S) before hydrogenation. The analysis results are shown in Table 1.

[0099] <(Polymerization Example 2) Rubber-like polymer (T) before hydrogenation> A 40 L internal volume, temperature-controllable autoclave equipped with a stirrer and a jacket was used as a reactor, and 2,100 g of 1,3-butadiene, 780 g of styrene, 21,000 g of cyclohexane, and 30 mmol of tetrahydrofuran (THF) and 15.4 mmol of 2,2-bis(2-oxolanyl)propane as polar substances, which had been previously removed from impurities, were placed in the reactor, and the internal temperature of the reactor was maintained at 42°C. As a polymerization initiator, 21.1 mmol of n-butyllithium was fed into the reactor. After the polymerization reaction started, the temperature inside the reactor began to rise due to heat generated by the polymerization, and after the monomer conversion in the reactor reached 98%, 120 g of 1,3-butadiene was added and reacted. The final temperature inside the reactor reached 78°C. Two minutes after this reaction temperature peak, 7.9 mmol of N-benzylidene-3-(trimethoxysilyl)-1-propanamine (Compound 1) was added to the reactor, and the coupling reaction was carried out for 20 minutes. 4.8 mmol of methanol was added to this polymer solution as a reaction terminator to obtain a rubbery polymer solution (TS). A portion of the rubbery polymer solution before hydrogenation was withdrawn and the solvent was removed in a dryer to obtain a rubbery polymer (T) before hydrogenation. The analysis results are shown in Table 1.

[0100] <(Polymerization Example 3) Rubber-like polymer (U) before hydrogenation> A 40 L internal volume, temperature-controllable autoclave equipped with a stirrer and a jacket was used as a reactor, and 450 g of styrene, 21,000 g of cyclohexane, and 30 mmol of tetrahydrofuran (THF) and 6.2 mmol of 2,2-bis(2-oxolanyl)propane as polar substances, from which impurities had been removed in advance, were placed in the reactor, and the internal temperature of the reactor was maintained at 44°C. As a polymerization initiator, 24.4 mmol of n-butyllithium was fed to the reactor. After the polymerization reaction started, the temperature inside the reactor began to rise due to heat generated by the polymerization. After the monomer conversion in the reactor reached 98%, 2,220 g of 1,3-butadiene was added, and one minute after the addition was completed, 120 g of styrene was added and the reaction was carried out. The final temperature inside the reactor reached 78°C. Two minutes after this reaction temperature peak, 9.1 mmol of N-benzylidene-3-(trimethoxysilyl)-1-propanamine (Compound 1) was added to the reactor, and the coupling reaction was carried out for 20 minutes. 5.6 mmol of methanol was added to this polymer solution as a reaction terminator to obtain a rubbery polymer solution (US). A portion of the rubbery polymer solution (US) before hydrogenation was withdrawn and the solvent was removed in a dryer to obtain a rubbery polymer (U) before hydrogenation. The analysis results are shown in Table 1.

[0101] <(Polymerization Example 4) Rubber-like polymer (V) before hydrogenation> A temperature-controllable autoclave having an internal volume of 40 L, equipped with a stirrer and a jacket, was used as a reactor. 3,000 g of 1,3-butadiene, from which impurities had been removed in advance, 21,000 g of cyclohexane, and 30 mmol of tetrahydrofuran (THF) and 4.5 mmol of 2,2-bis(2-oxolanyl)propane as polar substances were placed in the reactor, and the internal temperature of the reactor was maintained at 41°C. As a polymerization initiator, 30.0 mmol of n-butyllithium was fed into the reactor. After the polymerization reaction began, the temperature inside the reactor began to rise due to heat generated by the polymerization, and eventually reached 80°C. Two minutes after this reaction temperature peak, 11.2 mmol of N-benzylidene-3-(trimethoxysilyl)-1-propanamine (compound 1) was added to the reactor, and the coupling reaction was carried out for 20 minutes. 6.9 mmol of methanol was added to this polymer solution as a reaction terminator to obtain a rubbery polymer solution (VS). A portion of the rubbery polymer solution before hydrogenation was withdrawn and the solvent was removed in a dryer to obtain a rubbery polymer (V) before hydrogenation. The analysis results are shown in Table 1.

[0102] <(Polymerization Example 5) Rubber-like polymer (W) before hydrogenation> A 40 L internal volume autoclave equipped with a stirrer and a jacket and capable of temperature control was used as a reactor, and 2,160 g of 1,3-butadiene, 300 g of styrene, 21,000 g of cyclohexane, and 30 mmol of tetrahydrofuran (THF) and 1.4 mmol of 2,2-bis(2-oxolanyl)propane as polar substances, which had been previously removed from impurities, were placed in the reactor, and the internal temperature of the reactor was maintained at 48°C. As a polymerization initiator, 12.2 mmol of n-butyllithium was fed into the reactor. After the polymerization reaction started, the temperature inside the reactor began to rise due to heat generated by the polymerization, and after the monomer conversion in the reactor reached 98%, 540 g of 1,3-butadiene was added and reacted. The final temperature inside the reactor reached 73°C. Two minutes after this reaction temperature peak, 4.5 mmol of N-benzylidene-3-(trimethoxysilyl)-1-propanamine (Compound 1) was added to the reactor, and the coupling reaction was carried out for 20 minutes. 3.0 mmol of methanol was added to this polymer solution as a reaction terminator to obtain a rubbery polymer solution (WS). A portion of the rubbery polymer solution before hydrogenation was withdrawn and the solvent was removed in a dryer to obtain a rubbery polymer (W) before hydrogenation. The analysis results are shown in Table 1.

[0103] <(Polymerization Example 6) Rubber-like polymer (X) before hydrogenation> A 40 L internal volume, temperature-controllable autoclave equipped with a stirrer and a jacket was used as a reactor, and 2,160 g of 1,3-butadiene, 300 g of styrene, 21,000 g of cyclohexane, and 30 mmol of tetrahydrofuran (THF) and 3.6 mmol of 2,2-bis(2-oxolanyl)propane as polar substances, which had been previously removed from impurities, were placed in the reactor, and the internal temperature of the reactor was maintained at 46°C. As a polymerization initiator, 23.9 mmol of n-butyllithium was fed into the reactor. After the polymerization reaction started, the temperature inside the reactor began to rise due to heat generated by the polymerization, and after the monomer conversion in the reactor reached 98%, 540 g of 1,3-butadiene was added and reacted. The final temperature inside the reactor reached 76°C. Two minutes after this reaction temperature peak, 9.0 mmol of trimethoxymethylsilane (compound 2) was added to the reactor, and the coupling reaction was carried out for 20 minutes. 5.5 mmol of methanol was added to this polymer solution as a reaction terminator to obtain a rubbery polymer solution (XS). A portion of the rubber polymer solution before hydrogenation was withdrawn and the solvent was removed in a dryer to obtain a rubber polymer (X) before hydrogenation. The analysis results are shown in Table 1.

[0104] (Preparation of Rubber Composition) <(Example 1) Rubber Composition (SH-1)> The hydrogenation catalyst (TC-1) prepared in (Production Example 1) was added to the rubbery polymer solution (SS) before hydrogenation obtained in (Polymerization Example 1) in an amount of 70 ppm (based on titanium) per 100 parts by mass of the rubbery polymer before hydrogenation, and a hydrogenation reaction was carried out for 50 minutes at a hydrogen pressure of 0.8 MPa and an average temperature of 85°C to obtain a rubbery polymer (S-1). The iodine value of the resulting rubbery polymer was 85. To the resulting rubbery polymer solution, 12.6 g of n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol were added as antioxidants, and then 6,000 g of the rubber composition solution was subjected to the solvent removal method described above under <Solvent Removal Condition 1>, followed by drying in a dryer to obtain a rubber composition (SH-1). The results of the analysis are shown in Table 2.

[0105] <(Example 2) Rubber Composition (SH-2)> The hydrogenation catalyst (TC-1) prepared in (Production Example 1) was added to the rubbery polymer solution (SS) before hydrogenation obtained in (Polymerization Example 1) in an amount of 70 ppm (based on titanium) per 100 parts by mass of the rubbery polymer before hydrogenation, and a hydrogenation reaction was carried out for 100 minutes at a hydrogen pressure of 0.8 MPa and an average temperature of 85°C to obtain a rubbery polymer (S-2). The iodine value of the resulting rubbery polymer was 38. To the resulting rubbery polymer solution, 12.6 g of n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol were added as antioxidants, and then 6,000 g of the rubber composition solution was subjected to the solvent removal method described above under <Solvent Removal Condition 1>, followed by drying in a dryer to obtain a rubber composition (SH-2). The results of the analysis are shown in Table 2.

[0106] <(Example 3) Rubber Composition (SH-3)> The hydrogenation catalyst (TC-1) prepared in (Production Example 1) was added to the rubbery polymer solution (SS) before hydrogenation obtained in (Polymerization Example 1) in an amount of 110 ppm (based on titanium) per 100 parts by mass of the rubbery polymer before hydrogenation, and a hydrogenation reaction was carried out for 50 minutes at a hydrogen pressure of 0.8 MPa and an average temperature of 90°C to obtain a rubbery polymer (S-3). The iodine value of the resulting rubbery polymer was 85. To the resulting rubbery polymer solution, 12.6 g of n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol were added as antioxidants, and then 6,000 g of the rubber composition solution was subjected to the solvent removal method described above under <Solvent Removal Condition 1>, followed by drying in a dryer to obtain a rubber composition (SH-3). The results of the analysis are shown in Table 2.

[0107] <(Example 4) Rubber Composition (SH-4)> The hydrogenation catalyst (TC-1) prepared in (Production Example 1) was added to the rubbery polymer solution (SS) before hydrogenation obtained in (Polymerization Example 1) in an amount of 60 ppm (based on titanium) per 100 parts by mass of the rubbery polymer before hydrogenation, and a hydrogenation reaction was carried out for 60 minutes at a hydrogen pressure of 0.8 MPa and an average temperature of 85°C to obtain a rubbery polymer (S-4). The iodine value of the resulting rubbery polymer was 85. To the obtained rubbery polymer solution, 12.6 g of n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol were added as antioxidants, and then 6,000 g of the rubber composition solution was subjected to the method described above in <Solvent Removal Condition 2> to remove the solvent, and the solution was dried in a dryer to obtain a rubber composition (SH-4). The results of the analysis are shown in Table 2.

[0108] <(Example 5) Rubber Composition (TH-1)> The hydrogenation catalyst (TC-1) prepared in (Production Example 1) was added to the rubbery polymer solution (TS) before hydrogenation obtained in (Polymerization Example 2) in an amount of 70 ppm (based on titanium) per 100 parts by mass of the rubbery polymer before hydrogenation, and a hydrogenation reaction was carried out for 60 minutes at a hydrogen pressure of 0.8 MPa and an average temperature of 85°C to obtain a rubbery polymer (T-1). The iodine value of the resulting rubbery polymer was 70. To the obtained rubbery polymer solution, 12.6 g of n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol were added as antioxidants, and then 6,000 g of the rubber composition solution was subjected to the solvent removal method described above under <Solvent Removal Condition 1>, followed by drying in a dryer to obtain a rubber composition (TH-1). The results of the analysis are shown in Table 2.

[0109] <(Example 6) Rubber Composition (SH-5)> The hydrogenation catalyst (TC-1) prepared in (Production Example 1) was added to the rubbery polymer solution (SS) before hydrogenation obtained in (Polymerization Example 1) in an amount of 70 ppm (based on titanium) per 100 parts by mass of the rubbery polymer before hydrogenation, and a hydrogenation reaction was carried out for 100 minutes at a hydrogen pressure of 0.8 MPa and an average temperature of 85°C to obtain a rubbery polymer (S-5). The iodine value of the resulting rubbery polymer was 38. To the resulting rubbery polymer solution, 12.6 g of n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol were added as antioxidants, and at the same time, 150 g of SRAE oil (JOMO Process NC140, manufactured by JX Nippon Oil & Energy Corporation) was added and mixed. After that, the solvent was removed from 6,000 g of the rubber composition solution using the method described above in <Solvent Removal Condition 1>, and the mixture was dried in a dryer to obtain a rubber composition (SH-5). The results of the analysis are shown in Table 2.

[0110] <(Example 7) Rubber Composition (SH-6)> The hydrogenation catalyst (TC-1) prepared in (Production Example 1) was added to the rubbery polymer solution (SS) before hydrogenation obtained in (Polymerization Example 1) in an amount of 70 ppm (based on titanium) per 100 parts by mass of the rubbery polymer before hydrogenation, and a hydrogenation reaction was carried out for 50 minutes at a hydrogen pressure of 0.8 MPa and an average temperature of 85°C to obtain a rubbery polymer (S-6). The iodine value of the resulting rubbery polymer was 85. To the obtained rubbery polymer solution, 12.6 g of n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol were added as antioxidants, and 6 g of stearic acid was added at the same time. After that, the solvent was removed from 6,000 g of the rubber composition solution by the method described above in <Solvent Removal Condition 1>, and the solution was dried in a dryer to obtain a rubber composition (SH-6). The results of the analysis are shown in Table 3.

[0111] <(Example 8) Rubber Composition (SH-7)> The hydrogenation catalyst (TC-1) prepared in (Production Example 1) was added to the rubbery polymer solution (SS) before hydrogenation obtained in (Polymerization Example 1) in an amount of 70 ppm (based on titanium) per 100 parts by mass of the rubbery polymer before hydrogenation, and a hydrogenation reaction was carried out for 50 minutes at a hydrogen pressure of 0.8 MPa and an average temperature of 85°C to obtain a rubbery polymer (S-7). The iodine value of the resulting rubbery polymer was 85. To the resulting rubbery polymer solution, 12.6 g of n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol were added as antioxidants, and then 6,000 g of the rubber composition solution was subjected to the solvent removal method described above under <Solvent Removal Condition 1> and dried in a dryer. The rubber composition (SH-7) was obtained by removing the rubber composition in half the time required in Example 1. The results of the analysis are shown in Table 3.

[0112] <(Example 9) Rubber Composition (TH-2)> The hydrogenation catalyst (TC-1) prepared in (Production Example 1) was added to the rubbery polymer solution (TS) before hydrogenation obtained in (Polymerization Example 2) in an amount of 70 ppm (based on titanium) per 100 parts by mass of the rubbery polymer before hydrogenation, and a hydrogenation reaction was carried out for 40 minutes at a hydrogen pressure of 0.8 MPa and an average temperature of 85°C to obtain a rubbery polymer (T-2). The iodine value of the resulting rubbery polymer was 129. To the obtained rubbery polymer solution, 12.6 g of n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol were added as antioxidants, and then 6,000 g of the rubber composition solution was subjected to the solvent removal method described above under <Solvent Removal Condition 1>, followed by drying in a dryer to obtain a rubber composition (TH-2). The results of the analysis are shown in Table 3.

[0113] <(Example 10) Rubber Composition (SH-8)> To the rubbery polymer solution (SS) before hydrogenation obtained in (Polymerization Example 1) was added the hydrogenation catalyst (TC-1) prepared in (Production Example 1) in an amount of 69 ppm based on titanium per 100 parts by mass of the rubbery polymer before hydrogenation, and further added the hydrogenation catalyst (TC-2) prepared in (Production Example 2) in an amount of 1 ppm based on titanium (2 ppm based on aluminum) per 100 parts by mass of the rubbery polymer before hydrogenation. The hydrogenation reaction was carried out for 50 minutes at a hydrogen pressure of 0.8 MPa and an average temperature of 85°C to obtain a rubbery polymer (S-8). The iodine value of the resulting rubbery polymer was 85. To the obtained rubbery polymer solution, 12.6 g of n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol were added as antioxidants, and then 6,000 g of the rubber composition solution was subjected to the method described above in <Solvent Removal Condition 2> to remove the solvent, and the solution was dried in a dryer to obtain a rubber composition (SH-8). The results of the analysis are shown in Table 3.

[0114] <(Example 11) Rubber Composition (WH-1)> The hydrogenation catalyst (TC-1) prepared in (Production Example 1) was added to the rubbery polymer solution (WS) before hydrogenation obtained in (Polymerization Example 5) in an amount of 70 ppm (based on titanium) per 100 parts by mass of the rubbery polymer before hydrogenation, and a hydrogenation reaction was carried out for 70 minutes at a hydrogen pressure of 0.8 MPa and an average temperature of 80°C to obtain a rubbery polymer (W-1). The iodine value of the resulting rubbery polymer was 85. To the resulting rubbery polymer solution, 12.6 g of n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol were added as antioxidants, and then 1050 g of SRAE oil (JOMO Process NC140, manufactured by JX Nippon Oil & Energy Corporation) was added and mixed. After that, the solvent was removed from 6000 g of the rubber composition solution using the method described above in <Solvent Removal Condition 1>, and the mixture was dried in a dryer to obtain a rubber composition (WH-1). The results of the analysis are shown in Table 3.

[0115] <(Example 12) Rubber Composition (XH-1)> The hydrogenation catalyst (TC-1) prepared in (Production Example 1) was added to the rubbery polymer solution (XS) before hydrogenation obtained in (Polymerization Example 6) in an amount of 70 ppm (based on titanium) per 100 parts by mass of the rubbery polymer before hydrogenation, and a hydrogenation reaction was carried out for 70 minutes at a hydrogen pressure of 0.8 MPa and an average temperature of 80°C to obtain a rubbery polymer (X-1). The iodine value of the resulting rubbery polymer was 85. To the resulting rubbery polymer solution, 12.6 g of n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol were added as antioxidants, and then 6,000 g of the rubber composition solution was subjected to the solvent removal method described above under <Solvent Removal Condition 1>, followed by drying in a dryer to obtain rubber composition (XH-1). The results of the analysis are shown in Table 3.

[0116] <(Comparative Example 1) Rubber Composition (SH-9)> To the rubbery polymer solution (SS) before hydrogenation obtained in (Polymerization Example 1) was added the hydrogenation catalyst (TC-1) prepared in (Production Example 1) in an amount of 66 ppm based on titanium per 100 parts by mass of the rubbery polymer before hydrogenation, and further added the hydrogenation catalyst (TC-2) prepared in (Production Example 2) in an amount of 4 ppm based on titanium (8 ppm based on aluminum) per 100 parts by mass of the rubbery polymer before hydrogenation. The hydrogenation reaction was carried out for 50 minutes at a hydrogen pressure of 0.8 MPa and an average temperature of 85°C to obtain a rubbery polymer (S-9). The iodine value of the resulting rubbery polymer was 85. To the obtained rubbery polymer solution, 12.6 g of n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol were added as antioxidants, and then 6,000 g of the rubber composition solution was subjected to the solvent removal method described above under <Solvent Removal Condition 1>, followed by drying in a dryer to obtain a rubber composition (SH-9). The results of the analysis are shown in Table 4.

[0117] <(Comparative Example 2) Rubber Composition (SH-10)> The hydrogenation catalyst (TC-1) prepared in (Production Example 1) was added to the rubbery polymer solution (SS) before hydrogenation obtained in (Polymerization Example 1) in an amount of 150 ppm (based on titanium) per 100 parts by mass of the rubbery polymer before hydrogenation, and a hydrogenation reaction was carried out for 40 minutes at a hydrogen pressure of 0.8 MPa and an average temperature of 90°C to obtain a rubbery polymer (S-10). The iodine value of the resulting rubbery polymer was 85. To the resulting rubbery polymer solution, 12.6 g of n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol were added as antioxidants, and then 6,000 g of the rubber composition solution was subjected to the solvent removal method described above under <Solvent Removal Condition 1>, followed by drying in a dryer to obtain a rubber composition (SH-10). The results of the analysis are shown in Table 4.

[0118] <(Comparative Example 3) Rubber Composition (TH-3)> The hydrogenation catalyst (TC-1) prepared in (Production Example 1) was added to the rubbery polymer solution (TS) before hydrogenation obtained in (Polymerization Example 2) in an amount of 70 ppm (based on titanium) per 100 parts by mass of the rubbery polymer before hydrogenation, and a hydrogenation reaction was carried out for 40 minutes at a hydrogen pressure of 0.8 MPa and an average temperature of 85°C to obtain a rubbery polymer (T-3). The iodine value of the resulting rubbery polymer was 156. To the obtained rubbery polymer solution, 12.6 g of n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol were added as antioxidants, and then 6,000 g of the rubber composition solution was subjected to the solvent removal method described above under <Solvent Removal Condition 1>, followed by drying in a dryer to obtain a rubber composition (TH-3). The results of the analysis are shown in Table 4.

[0119] <(Comparative Example 4) Rubber Composition (UH-1)> The hydrogenation catalyst (TC-1) prepared in (Production Example 1) was added to the rubbery polymer solution (US) before hydrogenation obtained in (Polymerization Example 3) in an amount of 70 ppm (based on titanium) per 100 parts by mass of the rubbery polymer before hydrogenation, and a hydrogenation reaction was carried out for 60 minutes at a hydrogen pressure of 0.8 MPa and an average temperature of 85°C to obtain a rubbery polymer (U-1). The iodine value of the resulting rubbery polymer was 70. To the resulting rubbery polymer solution, 12.6 g of n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol were added as antioxidants, and then 6,000 g of the rubber composition solution was subjected to the solvent removal method described above under <Solvent Removal Condition 1>, followed by drying in a dryer to obtain a rubber composition (UH-1). The results of the analysis are shown in Table 4.

[0120] <(Comparative Example 5) Rubber Composition (VH-1)> The hydrogenation catalyst (TC-1) prepared in (Production Example 1) was added to the rubbery polymer solution (VS) before hydrogenation obtained in (Polymerization Example 4) in an amount of 70 ppm (based on titanium) per 100 parts by mass of the rubbery polymer before hydrogenation, and a hydrogenation reaction was carried out for 120 minutes at a hydrogen pressure of 0.9 MPa and an average temperature of 85°C to obtain a rubbery polymer (V-1). The iodine value of the resulting rubbery polymer was 9. To the resulting rubbery polymer solution, 12.6 g of n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol were added as antioxidants, and then 6,000 g of the rubber composition solution was subjected to the solvent removal method described above under <Solvent Removal Condition 1>, followed by drying in a dryer to obtain rubber composition (VH-1). The results of the analysis are shown in Table 4.

[0121] <(Comparative Example 6) Rubber Composition (SH-11)> The hydrogenation catalyst (TC-1) prepared in (Production Example 1) was added to the rubbery polymer solution (SS) before hydrogenation obtained in (Polymerization Example 1) in an amount of 8 ppm (based on titanium) per 100 parts by mass of the rubbery polymer before hydrogenation, and a hydrogenation reaction was carried out for 200 minutes at a hydrogen pressure of 1.8 MPa and an average temperature of 75°C to obtain a rubbery polymer (S-11). The iodine value of the resulting rubbery polymer was 85. To the resulting rubbery polymer solution, 12.6 g of n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol were added as antioxidants, and then 6,000 g of the rubber composition solution was subjected to the solvent removal method described above under <Solvent Removal Condition 2>, followed by drying in a dryer to obtain a rubber composition (SH-11). The results of the analysis are shown in Table 4.

[0122] <(Comparative Example 7) Rubber Composition (SH-12)> The hydrogenation catalyst (TC-2) prepared in (Production Example 2) was added to the rubbery polymer solution (SS) before hydrogenation obtained in (Polymerization Example 1) in an amount of 100 ppm (based on titanium) per 100 parts by mass of the rubbery polymer before hydrogenation, and a hydrogenation reaction was carried out for 30 minutes at a hydrogen pressure of 0.8 MPa and an average temperature of 90°C to obtain a rubbery polymer (S-12). The iodine value of the resulting rubbery polymer was 85. To the resulting rubbery polymer solution, 12.6 g of n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate and 3.0 g of 4,6-bis(octylthiomethyl)-o-cresol were added as antioxidants. Furthermore, N-pyridine oxide dissolved in 2 times the molar amount of ethanol was added, and an aqueous solution of 2 times the molar amount of citric acid dissolved in 2 times the volume of water relative to the metal residue was added. The mixture was mixed for 1 second at 60°C and 7600 rpm using a rotating disperser (Nikko Kogyo Co., Ltd., Cavitron 1010) with an interlocking mechanism to obtain a mixed solution. The P / V value at this time was 25 x 10 4 (kw / m 3 ), and the peripheral speed was 28 (m / s). The resulting mixture was then sent to a tank heated to 60°C, where it was allowed to stand for 5 minutes to separate the polymer solution phase and the aqueous phase. After the aqueous phase was removed, the polymer solution was vacuum dried to obtain a rubber composition (SH-11). The solvent removal method is shown in Table 4 as <Solvent Removal Condition 3>. The results of the analysis are shown in Table 4.

[0123] [Table 1]

[0124] In Table 1, the modifying agents Compounds 1 and 2 are shown below. Compound 1: N-benzylidene-3-(trimethoxysilyl)-1-propanamine Compound 2: Trimethoxymethylsilane

[0125] [Table 2]

[0126] [Table 3]

[0127] [Table 4]

[0128] [Examples 13 to 15] [Comparative Examples 8 to 11] [Preparation of rubber composition for crosslinking and evaluation of physical properties] Using the rubber compositions (SH-1 to SH-3, SH-9, TH-3, UH-1, VH-1) of (Examples 1 to 3), (Comparative Example 1), and (Comparative Examples 3 to 5) shown in Tables 2 to 4 as raw rubber components, crosslinkable rubber compositions containing each raw rubber were obtained according to the formulation shown below.

[0129] (rubber component) Rubber composition (samples: SH-1 to SH-3, SH-9, TH-3, UH-1, VH-1) : 80 parts by weight (parts by weight excluding rubber softener) High-cis polybutadiene (Ube Industries, Ltd. product name "UBEPOL BR150") :20 parts by mass

[0130] (Combination conditions) The amount of each compounding ingredient added is shown as parts by mass per 100 parts by mass of the rubber component not including the rubber softener. Silica 1 (trade name "Ultrasil 7000GR" manufactured by Evonik Degussa, nitrogen adsorption specific surface area 170 m2 / g): 50.0 parts by mass Silica 2 (Rhodia's Zeosil Premium 200MP, nitrogen adsorption specific surface area 220 m / g): 25.0 parts by mass Carbon black (product name "Seat KH (N339)" manufactured by Tokai Carbon Co., Ltd.): 5.0 parts by mass Silane coupling agent (product name "Si75" manufactured by Evonik Degussa, bis(triethoxysilylpropyl) disulfide): 6.0 parts by mass SRAE oil (product name "Process NC140" manufactured by JX Nippon Oil & Energy Corporation): 25.0 parts by mass ·Zinc white: 2.5 parts by mass Stearic acid: 1.0 parts by weight Antioxidant (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine): 2.0 parts by mass ·Sulfur: 2.2 parts by mass Vulcanization accelerator 1 (N-cyclohexyl-2-benzothiazylsulfinamide): 1.7 parts by mass Vulcanization accelerator 2 (diphenyl guanidine): 2.0 parts by mass ·Total: 222.4 parts by mass

[0131] (Mixing method) The above materials were kneaded by the following method to obtain a rubber composition. In the first stage of mixing, raw rubber (samples SH-1 to SH-3, SH-9, TH-3, UH-1, VH-1), fillers (silica 1, silica 2, carbon black), silane coupling agent, SRAE oil, zinc oxide, and stearic acid were mixed using an internal mixer (internal capacity 0.3 L) equipped with a temperature control device at a filling rate of 65% and a rotor rotation speed of 30 to 50 rpm. At this time, the temperature of the internal mixer was controlled so that the discharge temperature was 155 to 160°C, and each rubber composition (compound) was obtained. Next, in the second stage of mixing, the mixture obtained above was cooled to room temperature, and then an antioxidant was added and mixed again to improve the dispersion of the silica. In this case, the discharge temperature of the mixture was also adjusted to 155 to 160°C by controlling the temperature of the mixer. After cooling, the mixture was kneaded in the third stage using an open roll set at 70°C, adding sulfur and vulcanization accelerators 1 and 2. The mixture was then molded and vulcanized in a vulcanization press at 160°C for 20 minutes. The rubber compositions before and after vulcanization were evaluated. Specifically, they were evaluated by the following methods. The results are shown in Table 5.

[0132] (Evaluation 1, 2) Wet skid resistance, fuel economy (viscoelasticity parameters) Viscoelastic parameters were measured in torsion mode using a viscoelastic testing machine "ARES" manufactured by Rheometrics Scientific. Tan δ measured at 0°C, a frequency of 10 Hz, and a strain of 1% was used as an index of wet skid resistance. A higher index indicates better wet skid resistance. Tan δ measured at 50°C, a frequency of 10 Hz, and a strain of 3% was used as an index of fuel economy. The smaller the index, the better the fuel economy. Table 5 below lists symbols indicating when wet skid resistance and fuel economy change within the following ranges, based on the physical properties of the compound using the rubber composition (SH-9) of (Comparative Example 1). △: Less than 5% worsening to less than 5% improvement, 〇: 5% or more improvement to less than 15% improvement, ◎: 15% or more improvement to less than 20% improvement, ×: 5% or more worsening

[0133] (Evaluation 3) Breakdown characteristics The breaking strength and breaking elongation were measured in accordance with the tensile test method of JIS K 6251. The product of the measured values of the breaking strength and the breaking elongation was taken as the fracture property. Table 5 below lists symbols for when the fracture properties change within the following ranges, based on the physical properties of the compound using the rubber composition (SH-9) of (Comparative Example 1). △: Less than 5% worsening to less than 5% improvement, 〇: 5% or more improvement to less than 15% improvement, ◎: 15% or more improvement to less than 20% improvement, ×: 5% or more worsening

[0134] [Table 5]

[0135] As shown in Tables 2 to 4, it was confirmed that, compared with the comparative examples, the bale molded products of the rubber compositions in Examples 1 to 12 showed smaller Mooney fluctuations over time, and were excellent in mold contamination resistance, peel resistance of the rubber composition from the bale molded product, and adhesion of the packaging sheet to the bale molded product. Furthermore, it was confirmed that the small increase in Mooney viscosity made the physical properties less likely to change over time, resulting in stable quality. Furthermore, it was confirmed that the mold was less likely to be contaminated, resulting in less contamination due to materials adhering to the mold during bale molding, and thus excellent production stability. Furthermore, it was confirmed that the rubber composition was less likely to peel from the bale molded product, resulting in less rubber composition peeling after bale molding, resulting in excellent bale moldability and excellent production stability. Furthermore, it was confirmed that the packaging sheet easily adhered to the bale molded product, resulting in a small gap between the packaging sheet and the bale, making condensation less likely to occur, and also making the product easier to handle during transportation. Furthermore, as shown in Table 5, it was confirmed that the rubber compositions for cross-linking using the rubber compositions of Examples 1 to 3 have a balance of physical properties equal to or better than the rubber composition for cross-linking using the rubber composition of Comparative Example 1, while the rubber compositions for cross-linking using the rubber compositions of Comparative Examples 3 to 5 have an inferior balance of physical properties. [Industrial Applicability]

[0136] The bale molded product of the rubber composition of the present invention is suitable as a constituent material of a rubber composition for crosslinking, and specifically has industrial applicability in the fields of tire components, interior and exterior parts of automobiles, vibration-proof rubber, belts, footwear, foams, various industrial goods, etc.

Claims

1. A rubbery polymer (A) which is a hydrogenated product of a conjugated diene polymer, contains 5% by mass or more of vinyl aromatic monomer units, has a modification rate of 40% by mass or more as measured by a column adsorption GPC method, has an iodine value of 10 to 140, has an ethylene structure of 3% by mass or more, and has a vinyl aromatic monomer block of less than 10% by mass; Titanium (C), Contains 3 ppm≦titanium (C) content≦120 ppm; A bale molded product of a rubber composition, having an aluminum (B) content of less than 2 ppm.

2. The rubber polymer (A) contains a nitrogen atom. The bale molded body according to claim 1 .

3. Further containing 30% by mass or less of a rubber softener (D), The bale molded body according to claim 1 or 2.

4. Contains water in an amount of 0.05% by mass or more and 1.5% by mass or less; The bale molded body according to any one of claims 1 to 3.

5. A method for producing a bale molded article of the rubber composition according to any one of claims 1 to 4, comprising: a step of polymerizing at least a conjugated diene monomer in a solution to obtain a rubbery polymer (A); a step of adding titanium (C) to the obtained solution containing the rubbery polymer (A) to obtain a rubber composition; a step of molding the obtained rubber composition; A method for producing a bale molded article of a rubber composition, comprising:

6. 6. The method for producing a bale molded body according to claim 5, wherein the hydrogenation step is carried out using a hydrogenation catalyst having an aluminum content of 0.05 mol or less per 1 mol of titanium content.

7. removing the solvent from the solution by steam stripping; The method for producing the bale molded article according to claim 5 or 6.

8. The rubber composition for a bale molded article according to any one of claims 1 to 4, a cross-linking agent; Contains The crosslinking agent is contained in an amount of 0.1 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the rubber component. Crosslinkable rubber composition.

9. A tire tread comprising the rubber composition for the bale molded article according to any one of claims 1 to 4.

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