Conjugated diene polymers, conjugated diene polymer compositions, and conjugated diene polymer crosslinks

Abstract

Provided are a conjugated diene polymer, a conjugated diene polymer composition, a conjugated diene polymer crosslinked product, and the like that have excellent compression set and cold resistance without involving any practical problems regarding workability and heat resistance. The present invention provides a conjugated diene polymer that satisfies mathematical formula (A): 35 (%) ≤ 100*(b+d) / (a+b+c+ d) ≤ 99 (%), where a, b, c, and d represent the molar fractions of structural units represented by structural formulae (1)-(4), respectively, and that has a Mooney viscosity of 25-125 at 100°C, a glass transition temperature of -50°C or lower as measured by differential scanning calorimetry (DSC), and a crystallization peak-derived crystallization heat quantity of 2.5-50 J / g.

Description

[Technical Field]

[0001] The present invention relates to conjugated diene polymers, conjugated diene polymer compositions, and conjugated diene polymer crosslinked products, etc. [Background technology]

[0002] In electronic components, some designs incorporate perfluoroketones for cooling and temperature monitoring of battery storage areas, requiring sealing properties in the gasket material. In addition to sealing, sulfur-free materials and heat resistance are also required to ensure long-term stable properties. In such cases, rubber compositions using EPDM (ethylene-propylene-diene copolymer rubber) have been proposed.

[0003] Another challenge for rubber itself is achieving both rubber hardness and cold resistance. For example, fuel cell vehicles require cold resistance because they must be designed to prevent inoperability due to freezing in any situation, including starting at low temperatures, driving, and being left in sub-zero temperatures after being stored in a warehouse. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2009-094056 [Patent Document 2] Japanese Patent Publication No. 2011-249283 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, conventionally proposed rubber compositions using EPDM have difficulty increasing crosslinking density and obtaining sufficiently good compression set. Furthermore, improving cold resistance is difficult from a polymer design perspective.

[0006] This invention has been made in view of the above-mentioned problems. Its purpose is to provide conjugated diene polymers, conjugated diene polymer compositions, and conjugated diene polymer crosslinks, etc., that have no practical problems in terms of processability and heat resistance, and that are excellent in compression set and cold resistance. [Means for solving the problem]

[0007] As a result of diligent research to solve the problems of the prior art described above, the inventors of the present invention have completed the present invention by designing a conjugated diene polymer having a specific structure.

[0008] In other words, the present invention is as follows:

[0009] <1> The following structural formulas (1) to (4); [ka] When the constituent molar ratios of each structural unit represented by are a, b, c, and d, respectively, The following formula (A); Formula (A): 35(%)≦100*(b+d) / (a+b+c+d)≦99(%) Satisfying the conditions, The Mooney viscosity at 100°C is between 25 and 125. The glass transition temperature measured by differential calorimetry (DSC) is -50°C or lower, and the heat of crystallization derived from the crystallization peak is between 2.5 J / g and 50 J / g. Conjugated diene polymers.

[0010] <2> Contains aromatic vinyl monomer units in an amount of 1.0% to 8.0% by mass. <1> The conjugated diene polymer described above.

[0011] <3> The following formula (B); Formula (B): 90(%) ≤ 100*b / (a+b) Satisfying <1> or <2> The conjugated diene polymer described above.

[0012] <4> The following formula (C); Formula (C): 100*(a + b) / (a + b + c + d) < 40 (%) satisfying The conjugated diene polymer according to any one of <1> to <3>.

[0013] <5> In the molecular weight distribution curve in gel permeation chromatography (GPC), having at least two peaks, [[ID=​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​ <10> The above formula (A) is 50% or more. <1> ~ <9> A conjugated diene polymer as described in any one of the items.

[0019] <11> The silicon content is 100 ppm or less. <1> ~ <10> A conjugated diene polymer as described in any one of the items.

[0020] <12> <1> ~ <11> It contains 100 parts by mass of a conjugated diene polymer described in any one of the above items and 10 parts by mass or more of a filler, The aforementioned filler comprises one or more selected from the group consisting of silica-based inorganic fillers, carbon black, and calcium carbonate. A conjugated diene polymer composition.

[0021] <13> The filler contains at least the carbon black, The mass percentage of carbon black contained in the filler is 30% by mass or more. <12> The conjugated diene polymer composition described above.

[0022] <14> <12> or <13> The vulcanization composition includes the conjugated diene polymer composition described above and an organic peroxide. Conjugated diene polymer crosslinked product. [Effects of the Invention]

[0023] According to the present invention, it is possible to provide conjugated diene polymers, conjugated diene polymer compositions, and conjugated diene polymer crosslinked products, etc., that have no practical problems in terms of processability and heat resistance, and that are excellent in compression set and cold resistance. [Modes for carrying out the invention]

[0024] The embodiments of the present invention (hereinafter referred to as "these embodiments") will be described in detail below. The following embodiments are illustrative examples for explaining the present invention, and the present invention is not limited thereto. That is, the present invention can be modified and implemented without departing from its essence. In this specification, when "~" is used to enclose numerical values ​​or physical properties, it is used to include the values ​​before and after it.

[0025] Furthermore, in this specification, "monomer" means the compound before polymerization, and "monomer unit" means the constituent unit that makes up the polymer.

[0026] [Conjugated diene polymers] The conjugated diene polymer of this embodiment satisfies the following formula (A) when the molar ratios of the structural units represented by the following structural formulas (1) to (4) are a, b, c, and d, respectively. Formula (A): 35(%)≦100*(b+d) / (a+b+c+d)≦99(%)

[0027] Structural formula [ka]

[0028] In the conjugated diene polymer of this embodiment, the structural unit represented by structural formula (1) corresponds, for example, to the 1,2-vinyl bond unit of the conjugated diene compound. However, the raw materials are not particularly limited as long as they are the same as the structural unit represented by structural formula (1).

[0029] Let a be the molar ratio of the structural units represented by the above structural formula (1).

[0030] Furthermore, when the total value of each structural unit represented by the structural formulas (1) to (4) is set to 100 mol%, the molar ratio of a is preferably 0.0 mol% or more and 3.0 mol% or less, more preferably 0.2 mol% or more and 2.6 mol% or less, and even more preferably 0.4 mol% or more and 2.4 mol% or less. When the molar ratio of a is within the above preferred range, the vulcanized product tends to have excellent tensile strength, elongation at break, and ozone resistance.

[0031] In the conjugated diene polymer of this embodiment, the structural unit represented by structural formula (2) corresponds, for example, to a conjugated diene compound in which the 1,2-vinyl bond unit has been hydrogenated. However, the raw materials are not particularly limited as long as they are the same as the structural unit represented by structural formula (2).

[0032] Let b be the molar ratio of the structural units represented by the above structural formula (2).

[0033] Furthermore, when the total value of each structural unit represented by structural formulas (1) to (4) is set to 100 mol%, the molar ratio of b is preferably 2.0 mol% to 45.0 mol%, more preferably 3.0 mol% to 40.0 mol%, even more preferably 5.0 mol% to 37.0 mol%, and particularly preferably 10.0 mol% to 37.0 mol%. When the molar ratio of b is within the above preferred range, the vulcanized product tends to have excellent tensile strength and elongation at break.

[0034] In the conjugated diene polymer of this embodiment, the structural unit represented by structural formula (3) corresponds, for example, to the 1,4-cis bond unit and the 1,4-trans bond unit of the conjugated diene compound. However, the raw materials are not particularly limited as long as they are the same as the structural unit represented by formula (3).

[0035] Let c be the molar ratio of the structural units represented by the above structural formula (3).

[0036] Furthermore, when the total value of each structural unit represented by structural formulas (1) to (4) is set to 100 mol%, the molar ratio of c is preferably 2.0 mol% or more and 60.0 mol% or less, more preferably 3.0 mol% or more and 50.0 mol% or less, even more preferably 5.0 mol% or more and 40.0 mol% or less, and particularly preferably 7.0 mol% or more and 30.0 mol% or less. When the molar ratio of c is within the above preferred range, the crosslinking properties tend to be good when forming the copolymer composition described later.

[0037] Here, the content of 1,4-cis bonds and 1,4-trans bonds is: 13 It can be measured using 1C-NMR. Specifically, it can be measured by the method described in the examples below.

[0038] Furthermore, in the structural unit represented by formula (3), the content of 1,4-cis bonds and 1,4-trans bonds can be controlled to the above-mentioned numerical range by adjusting the type of polymerization initiator, the type of polar compound, and the amount added, as described later.

[0039] In the conjugated diene polymer of this embodiment, the structural unit represented by structural formula (4) corresponds to, for example, an ethylene structure or a conjugated diene compound in which the 1,4-cis and 1,4-trans bond units have been hydrogenated. However, the raw materials are not particularly limited as long as they are the same as the structural unit represented by formula (4).

[0040] The molar ratio of the structural units represented by the above structural formula (4) is denoted as d.

[0041] Furthermore, when the total value of each structural unit represented by the structural formulas (1) to (4) is set to 100 mol%, the molar ratio of d is preferably 5.0 mol% or more and 60.0 mol% or less, more preferably 10.0 mol% or more and 55.0 mol% or less, even more preferably 15.0 mol% or more and 50.0 mol% or less, and particularly preferably 20.0 mol% or more and 65.0 mol% or less. When the molar ratio of d is within the above preferred range, the vulcanized product tends to have excellent tensile strength, elongation at break, and ozone resistance.

[0042] The molar ratios a to d of each structural unit represented by the above structural formulas (1) to (4) are as described in the examples below. 1 It can be measured using 1H-NMR.

[0043] In the conjugated diene polymer of this embodiment, there are no particular limitations on the method for controlling the molar ratio a to d of each structural unit represented by the structural formulas (1) to (4) to the preferred range, but examples include controlling the amount of 1,2-vinyl bonds in the copolymer before hydrogenation by the amount of polar substance added during polymerization and the polymerization temperature, or controlling the hydrogenation rate.

[0044] Furthermore, the molar ratios a to d of each structural unit represented by the structural formulas (1) to (4) satisfy formula (A). Formula (A) corresponds, for example, to the hydrogenation rate of the conjugated diene monomer component.

[0045] From the viewpoint of heat resistance, the lower limit of formula (A) is preferably 35% or more, more preferably 45% or more, even more preferably 50% or more, and particularly preferably 55% or more. On the other hand, from the viewpoint of ensuring crosslinking properties and reducing compression set, the upper limit of formula (A) is preferably 99% or less, more preferably 96% or less, even more preferably 90% or less, and particularly preferably less than 90%.

[0046] (Hydrogenation reaction) The conjugated diene polymer of this embodiment may also be a hydrogenated copolymer. In this case, for example, the conjugated diene polymer of this embodiment can be obtained by hydrogenating the conjugated diene portion described later.

[0047] The method for hydrogenating the conjugated diene portion of the copolymer is not particularly limited, and known methods can be used. However, as described in International Publication No. 96 / 05250, Japanese Patent Publication No. 2000-053706, International Publication No. 2003 / 085010, International Publication No. 2019 / 151126, International Publication No. 2019 / 151127, International Publication No. 2002 / 002663, and International Publication No. 2015 / 006179, a preferred method involves polymerizing the conjugated diene monomer by anionic polymerization under various additives and conditions, copolymerizing it with other monomers as needed, and then hydrogenating it.

[0048] The hydrogenation rate of hydrogenated conjugated diene polymers refers to the proportion (molar ratio) of double bonds in the structure derived from the conjugated diene monomer unit that become saturated bonds through the hydrogenation reaction.

[0049] The hydrogenation rate can be controlled within the above numerical range by adjusting the amount of hydrogen added, the reaction temperature, the reaction time, the type of catalyst, and the amount of catalyst added.

[0050] Hydrogenation reactions can be carried out as batch processes, continuous processes, or a combination of both.

[0051] When the conjugated diene polymer of this embodiment is a hydrogenated copolymer, the hydrogenation rate is preferably 35% to 98% of the structural units derived from the conjugated diene compound (e.g., butadiene), and more preferably 40% to 98%.

[0052] The hydrogenation rate can be controlled by the amount of hydrogen added to the structural units derived from the conjugated diene compound.

[0053] The temperature of the hydrogenation reaction is not particularly limited, but is preferably 60 to 105°C, and more preferably 70 to 100°C.

[0054] The hydrogenation rate is 1 It can be measured using 1H-NMR.

[0055] Here, it is preferable that the molar ratios a to d of each structural unit represented by the structural formulas (1) to (4) satisfy the following formula (B). Formula (B): 90(%) ≤ 100*b / (a+b)

[0056] Formula (B) above corresponds, for example, to the hydrogenation rate of the 1,2-vinyl bond in a conjugated diene monomer.

[0057] From the viewpoint of suppressing gelation, the above formula (B) is preferably 90% or more, more preferably 92% or more, and even more preferably 94% or more. The upper limit of formula (B) is not particularly limited, but is preferably 100% or less, more preferably less than 100%, and even more preferably 99% or less.

[0058] Furthermore, it is preferable that the molar ratios a to d of each structural unit represented by the structural formulas (1) to (4) satisfy the following formula (C). Formula (C): 100*(a+b) / (a+b+c+d)<40(%)

[0059] Formula (C) above represents, for example, the content ratio of 1,2-vinyl bonds in the conjugated diene monomer and butylene structures in which 1,2-vinyl bonds are hydrogenated, and corresponds to the amount of 1,2-vinyl bonds in the copolymer before hydrogenation.

[0060] The content of 1,2-vinyl bonds can be controlled by the polymerization temperature during polymerization and the amount of polar compounds added, as described later. Furthermore, the amount of 1,2-vinyl bonds in the copolymer before hydrogenation... 1 This can be measured by 1H-NMR. When using the copolymer after hydrogenation as a sample, the so-called vinyl bond amount and butylene bond amount are targeted. 1The content of 1,2-vinyl bonds can be measured by 1H-NMR.

[0061] From the viewpoint of low-temperature characteristics, the above formula (C) is preferably less than 40%, more preferably 38% or less, and even more preferably 36% or less. On the other hand, from the viewpoint of improving productivity by shortening the polymerization reaction, it is preferably 15% or more, more preferably 17% or more, and even more preferably 20% or more.

[0062] In this embodiment, each structural unit represented by structural formulas (1) to (4) of the conjugated diene polymer is preferably a structural unit derived from a conjugated diene compound (hereinafter also referred to as "conjugated diene monomer") or a structural unit obtained by hydrogenating them.

[0063] The conjugated diene monomer is not particularly limited, but examples include 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, 1,3-butadiene and isoprene are preferred from the viewpoint of ease of industrial availability, and 1,3-butadiene is more preferred. These may be used individually or in combination of two or more.

[0064] Furthermore, the conjugated diene polymer of this embodiment may also contain structural units derived from aromatic vinyl compounds (hereinafter also referred to as "aromatic vinyl monomers").

[0065] Aromatic vinyl compounds are not particularly limited, but examples include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o,p-dimethylstyrene, o-ethylstyrene, m-ethylstyrene, p-ethylstyrene, α-methylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, and diphenylethylene. Among these, styrene is preferred from the viewpoint of ease of industrial availability. These may be used individually or in combination of two or more.

[0066] Furthermore, the conjugated diene polymer in this embodiment is preferably a hydrogenated product of a copolymer of a conjugated diene compound and an aromatic vinyl compound (hereinafter also referred to as "conjugated diene-aromatic vinyl copolymer").

[0067] In the conjugated diene polymer of this embodiment, the content of aromatic vinyl monomer units is preferably 1.0% by mass or more, more preferably 1.5% by mass or more, and even more preferably 2.0% by mass or more, from the viewpoint of the tensile strength and tear strength of the vulcanized product. On the other hand, from the viewpoint of crosslinkability, compression set, and low-temperature properties when forming a vulcanized product, the content of aromatic vinyl monomer units is preferably 14.0% by mass or less, more preferably 10.0% by mass or less, even more preferably 8.0% by mass or less, and particularly preferably 7.0% by mass or less.

[0068] The content of aromatic vinyl monomer units in the copolymer of this embodiment can be controlled to the above numerical range, for example, by adjusting the amount of aromatic vinyl monomer added during the polymerization process.

[0069] Here, the content of aromatic vinyl monomer units is: 1 The measurement can be performed using 1H-NMR. Specifically, the measurement is performed in accordance with the method described in the examples below.

[0070] In this embodiment, if the conjugated diene polymer is a hydrogenated conjugated diene-aromatic vinyl copolymer, it is preferable that the proportion of aromatic vinyl monomer units present individually is higher from the viewpoint of improving abrasion resistance. Furthermore, from the viewpoint of abrasion resistance, the content of aromatic vinyl monomer blocks in the conjugated diene polymer is less than 5.0% by mass, preferably 4.0% by mass or less, more preferably 3.5% by mass or less, even more preferably 3.0% by mass or less, and particularly preferably 2.0% by mass or less. In this specification, "aromatic vinyl monomer block" refers to a structure in which eight or more aromatic vinyl monomer units are linked together.

[0071] The method for measuring aromatic vinyl monomer blocks is not particularly limited, but known methods include, for example, measuring the chain of styrene units using NMR, as described in International Publication No. 2014 / 133097. Another method involves using a conjugated diene polymer before hydrogenation as a sample, decomposing the polymer by Kolthoff's method (as described in IMKOLTHOFF, et al., J. Polym. Sci. 1, 429 (1946)), and analyzing the amount of methanol-insoluble polystyrene.

[0072] In this case, the resulting vulcanized rubber is particularly preferable in terms of abrasion resistance and cold resistance.

[0073] [Glass transition temperature] The glass transition temperature of the conjugated diene polymer in this embodiment is -50°C or lower, preferably -60°C or lower, from the viewpoint of cold resistance. When the glass transition temperature is around -60°C, it can be used in applications where cold-resistant grade EPDM is used. From the viewpoint of improving properties at lower temperatures for use in applications such as hydrogen tanks and packing for fuel cell vehicles, -63°C or lower is more preferable, -65°C or lower is even more preferable, and -68°C or lower is particularly preferable.

[0074] If the glass transition temperature is -60°C or lower, it can generally be said that the rubber has superior cold resistance compared to EPDM, and by using this conjugated diene polymer, a conjugated diene polymer composition with excellent cold resistance can be obtained.

[0075] On the other hand, from the viewpoint of maintaining ozone resistance, the glass transition temperature is preferably -90°C or higher, more preferably -90°C or higher, even more preferably -87°C or higher, and particularly preferably -85°C or higher.

[0076] Furthermore, the glass transition temperature of the conjugated diene polymer can be controlled to the above range by adjusting, for example, the content of aromatic vinyl monomer units, the value of formula (A) above, the amount of vinyl bonds, the hydrogenation rate, etc.

[0077] Generally, the glass transition temperature of conjugated diene polymers tends to increase with increasing content of aromatic vinyl monomer units, and also tends to increase with increasing content of the structural unit represented by structural formula (4). On the other hand, in the case of hydrogenated conjugated diene polymers, the glass transition temperature tends to decrease as the proportion of hydrogenated 1,2-vinyl bonds increases.

[0078] When controlling the glass transition temperature of a conjugated diene polymer to, for example, -50°C or below, the aromatic vinyl monomer unit content is preferably 15% by mass or less, the 1,2-vinyl bond content is preferably 20 mol% to 45 mol%, and the hydrogenation rate is preferably 35% to 98%. Furthermore, when a conjugated diene polymer with a hydrogenation rate of 90% or more and a glass transition temperature of -60°C or below is used, the aromatic vinyl monomer unit content is preferably 10% by mass or less. When controlling the glass transition temperature of a conjugated diene polymer to, for example, -60°C or below, the aromatic vinyl monomer unit content is preferably 8% by mass or less, the 1,2-vinyl bond content is preferably 20 mol% to 40 mol%, and the hydrogenation rate is preferably 35% to 98%. Furthermore, when a conjugated diene polymer with a hydrogenation rate of 90% or more and a glass transition temperature of -60°C or below is used, the aromatic vinyl monomer unit content is preferably 6% by mass or less.

[0079] When controlling the glass transition temperature of a conjugated diene polymer to, for example, -70°C or lower, the aromatic vinyl monomer unit content is preferably 6% by mass or less, the 1,2-vinyl bond content is preferably 20 mol% to 40 mol%, and the hydrogenation rate is preferably 35% to 85%.

[0080] When controlling the glass transition temperature of a conjugated diene polymer to, for example, -80°C or lower, the aromatic vinyl monomer unit content is preferably 6% by mass or less, the 1,2-vinyl bond content is preferably 20 mol% to 40 mol%, and the hydrogenation rate is preferably 35% to 70%.

[0081] When the glass transition temperature of the conjugated diene polymer is within the above preferred range, the conjugated diene polymer composition and the conjugated diene polymer crosslinked product obtained using the conjugated diene polymer tend to have excellent fracture properties at low temperatures and low temperature dependence of stiffness in the room temperature range, resulting in high stability.

[0082] The glass transition temperature is determined according to ISO 22768:2006 by recording a DSC curve while increasing the temperature within a predetermined range, and the peak top (inflection point) of the resulting DSC differential curve, which originates from the glass transition, is defined as the glass transition temperature. Specifically, it can be measured by the method described in the examples below.

[0083] [Crystallization heat] The conjugated diene polymer of this embodiment is microcrystalline. Microcrystallineity can be measured using differential calorimetry (DSC) based on the heat of crystallization of the crystalline portion. The heat of crystallization of the conjugated diene polymer of this embodiment is 2.5 J / g or more and 50 J / g or less. From the viewpoint of suppressing precipitation from the solvent during polymerization and improving processability and cold resistance, it is preferably 48 J / g or less, more preferably 45 J / g or less, and particularly preferably 40 J / g or less. On the other hand, from the viewpoint of compression set, the heat of crystallization is 2.5 J / g or more, preferably 3.0 J / g or more, more preferably 4.0 J / g or more, and even more preferably 5.0 J / g or more. The heat of crystallization of the conjugated diene polymer is determined according to ISO 22768:2006 by recording the DSC curve while cooling within a predetermined temperature range and taking the peak area derived from crystallization in the resulting DSC differential curve. Specifically, it can be measured by the method described in the examples below.

[0084] The heat of crystallization of a conjugated diene polymer can be controlled within the above range by adjusting the aromatic vinyl monomer unit content, the value of formula (A), the amount of vinyl bonds, the hydrogenation rate, etc. In particular, the lower the content of the structural units represented by structural formula (1) and structural formula (2) and the higher the content of the structural unit represented by structural formula (4), the higher the heat of crystallization tends to be. Specifically, when the aromatic vinyl monomer unit content is 5% by mass and the total content of the structural units represented by structural formula (1) and structural formula (2) is 35 mol%, it is preferable that the content of the structural unit represented by structural formula (4) is 30 mol% or more and 63 mol% or less. When the aromatic vinyl monomer unit content is 7% by mass and the total content of the structural units represented by structural formula (1) and structural formula (2) is 25 mol%, it is preferable that the content of structural formula (4) is 25 mol% or more and 70 mol% or less.

[0085] The weight-average molecular weight (Mw) of the conjugated diene polymer in this embodiment is preferably 50,000 to 1,000,000, more preferably 80,000 to 900,000, even more preferably 120,000 to 800,000, and even more preferably 200,000 to 700,000, from the viewpoint of obtaining good compression set.

[0086] Furthermore, from the viewpoint of adhesion during production and moldability of the rubber bale, the weight-average molecular weight (Mw) of the conjugated diene copolymer in this embodiment is preferably within the aforementioned range.

[0087] The weight-average molecular weight (Mw) can be controlled to the above numerical range, for example, by adjusting the amount of polymerization initiator used.

[0088] The weight-average molecular weight (Mw) of the conjugated diene polymer in this embodiment can be measured by GPC (gel permeation chromatography). Specifically, it can be measured by the method described in the examples below.

[0089] [Number of peaks, peak area, and molecular weight distribution of GPC] The conjugated diene polymer of this embodiment preferably has at least two peaks in the molecular weight distribution curve obtained by GPC measurement.

[0090] In this embodiment, the GPC peak has an area of ​​3.0% or more when the total area of ​​the molecular weight distribution curve obtained by GPC measurement is set to 100%, and has a peak top. A peak top is a point where the maximum value is obtained between the baseline or the minimum value. Having two or more GPC peaks is preferable in terms of the balance between processability, wear resistance, and strength of the conjugated diene polymer in this embodiment.

[0091] If there are two or more peaks, the peak with the lowest molecular weight is designated as peak (A), and the peak with the highest molecular weight is designated as peak (B).

[0092] From the viewpoint of improving processability and preventing adhesion during production, the peak molecular weight of peak (A) is preferably 400,000 to 500,000. The lower limit of the peak molecular weight of peak (A) is more preferably 50,000 or more, even more preferably 60,000 or more, and particularly preferably 80,000 or more. The upper limit of the peak molecular weight of peak (A) is more preferably 450,000 or less, even more preferably 400,000 or less, and particularly preferably 360,000 or less.

[0093] From the viewpoint of suppressing cold flow, the area of ​​peak (B) is preferably 10% to 70%, more preferably 20% to 68%, and even more preferably 24% to 65%, when the total area of ​​the molecular weight distribution curve obtained by GPC measurement is taken as 100%.

[0094] The proportion of modified polymer in the polymer contained in peak (A) is preferably 50% to 99%, and more preferably 55% to 98%. The proportion of modified polymer in peak (A) can be said to be the modification rate of the conjugated diene polymer in peak (A). A proportion of modified polymer in peak (A) of 50% or more is preferable because it provides a good balance between low hysteresis loss and wet skid properties, as well as good compression set, while a proportion of 99% or less is preferable because it provides good processability.

[0095] The ratio of modified polymers within the polymer contained in peak (A) can be adjusted by controlling the type and amount of coupling agents and modifying agents added. For example, one method involves polymerizing a polymer, reacting a monofunctional modifying agent with the active ends of some of the polymers to form peak (A), while reacting the remaining polymer with a bifunctional or more functional coupling agent to obtain a polymer corresponding to peak (B), or adding a monofunctional modifying agent after adding a bifunctional or more functional modifying agent.

[0096] Furthermore, the ratio of modified polymers in the polymer contained in peak (A) can be adjusted by modifying the polymerization initiation end with an amine. The method for modifying the conjugated diene portion of the copolymer with an amine at the polymerization initiation end is not particularly limited, and known methods can be used. For example, as described in Japanese Patent Application Publication No. 2018-16678, a preferred method is to obtain a polymer chain having nitrogen atoms at the molecular ends by adding an organolithium compound as a polymerization initiator in the presence of an amine compound having active hydrogen. Examples of amine compounds having active hydrogen include piperidine, hexamethylene, azacyclooctane, 1,3,3-thrimethyl-6-azabicyclo[3.2.1]octane, 1,2,3,6-tetrahydropyridine, and 3,5-dimethylpiperidine.

[0097] Furthermore, the molecular weight distribution (weight-average molecular weight Mw / number-average molecular weight Mn) of the conjugated diene polymer in this embodiment is preferably 1.2 to 3.0, and more preferably 1.2 to 2.5, from the viewpoint of processability and bale hardness.

[0098] The Mooney viscosity (ML) of the conjugated diene polymer of this embodiment when using an L-type rotor at 100°C. 1+4 From the viewpoint of processability and compression set, the value is preferably 25 to 125, more preferably 28 to 120, and more preferably 30 to 118.

[0099] The Mooney viscosity of the conjugated diene polymer in this embodiment can be measured by the method described in the examples below.

[0100] Mooney viscosity (ML) of conjugated diene polymers at 100°C using an L-type rotor. 1+4 This can be controlled, for example, by the molecular weight and hydrogenation rate of the conjugated diene polymer. Specifically, if the weight-average molecular weight Mw is between 200,000 and 1,000,000, it can often be controlled within the above range.

[0101] Furthermore, since Mooney viscosity tends to increase with increasing hydrogenation rate, it is preferable to have a weight-average molecular weight Mw of 100,000 to 500,000 when the hydrogenation rate is 70% or more, and a weight-average molecular weight Mw of 200,000 to 800,000 when the hydrogenation rate is 50% or less.

[0102] [Dynamic viscoelasticity] In this embodiment, the conjugated diene polymer is preferably subjected to dynamic viscoelasticity measurement, and when the temperature dependence of tanδ is measured, the temperature at which the tanδ peak top is located is preferably between -85°C and -40°C.

[0103] When designing materials, in order to reduce the temperature dependence of physical properties and ensure the stability of physical properties in the usage environment, tanδ is preferably -40°C or lower, more preferably -43°C or lower, and even more preferably -45°C or lower. On the other hand, in order to crosslink conjugated diene polymers, it is necessary to control the amount of double bonds, so in material design, it tends to be -85°C or higher.

[0104] The temperature of the tanδ peak top can be controlled, for example, by the content of aromatic vinyl monomer units in the conjugated diene polymer, the content of structural units represented by structural formulas (1) to (4), the hydrogenation rate, etc.

[0105] [Silicon content] From the viewpoint of suppressing cold flow, the silicon content of the conjugated diene polymer in this embodiment is preferably 30 ppm or more, more preferably 33 ppm or more, and even more preferably 35 ppm or more. On the other hand, from the viewpoint of processability, the silicon content is preferably 200 ppm or less, more preferably 100 ppm or less, and even more preferably 80 ppm or less.

[0106] The silicon content can be controlled to the above numerical range by, for example, adjusting the amount and type of coupling agent or modifier containing nitrogen atoms, as described later.

[0107] [Titanium content, Aluminum content] When titanium is used as a hydrogenation catalyst component in the production of the conjugated diene polymer of this embodiment, the amount of titanium added is preferably 150 ppm or less relative to the conjugated diene polymer before hydrogenation.

[0108] The titanium content of the conjugated diene polymer is preferably 1 ppm to 100 ppm, more preferably 5 ppm to 90 ppm, and even more preferably 10 ppm to 80 ppm. A titanium content of 100 ppm or less prevents the conjugated diene polymer from becoming yellow, and a titanium content of 1 ppm or more eliminates the need for removal equipment, thereby reducing costs.

[0109] When aluminum is used as a hydrogenation catalyst component in the production of the conjugated diene polymer of this embodiment, the amount of aluminum added is preferably 6 ppm or less, more preferably 3 ppm or less, and even more preferably not added, relative to the conjugated diene polymer before hydrogenation.

[0110] In this embodiment, the aluminum content of the conjugated diene polymer is preferably 2 ppm or less, more preferably 1 ppm or less, and even more preferably aluminum-free, from the viewpoint of reducing catalyst safety during hydrogenation reactions. Furthermore, the function of aluminum as a co-catalyst can be complemented by using lithium or magnesium instead of aluminum.

[0111] Furthermore, from the viewpoint of suppressing the increase in Mooney viscosity (ML viscosity) and the handling and safety of the hydrogenation catalyst, the hydrogenation catalyst added during the production of hydrogenated conjugated diene polymers preferably contains 0.05 moles or less of aluminum per mole of titanium, more preferably 0.04 moles or less of aluminum, even more preferably 0.03 moles or less of aluminum, and most preferably contains no aluminum at all.

[0112] By adjusting the titanium and aluminum content in the hydrogenation catalyst, the titanium and aluminum content of the hydrogenated conjugated diene polymer can be controlled to the above numerical range.

[0113] [Nitrogen content] In this embodiment, from the viewpoint of improving the dispersibility of fillers when used in a composition, the nitrogen content in the conjugated diene polymer is preferably 60 to 600 ppm, and more preferably 80 to 500 ppm.

[0114] [Coupling copolymer] The conjugated diene polymer of this embodiment is preferably a coupling copolymer obtained by performing a coupling reaction on the active ends of a copolymer obtained through a polymerization step and, if necessary, a branching step using a branching agent, using a reactive compound with two or more functions (hereinafter also referred to as a "coupling agent").

[0115] In the coupling step, in which a coupling reaction is carried out using a coupling agent, a coupling reaction is performed on one end of the active end of the copolymer with a predetermined coupling agent or a modifying agent having a nitrogen atom-containing group to obtain the copolymer.

[0116] (Coupling agent) In this embodiment, the coupling agent that can be used in the coupling step may have any structure as long as it is a reactive compound with two or more functionalities.

[0117] The conjugated diene copolymer of this embodiment preferably contains nitrogen atoms. A conjugated diene copolymer containing nitrogen atoms can be obtained, for example, by carrying out a coupling reaction using a modifying agent having a nitrogen atom-containing group as described below.

[0118] (Modifying agent containing nitrogen atom groups) The conjugated diene polymer of this embodiment may be a conjugated diene polymer obtained by a polymerization step and, if necessary, a branching step, followed by a coupling reaction at the active end of the polymer using a reactive compound having two or more nitrogen atom-containing groups (hereinafter also referred to as a "modifying agent having nitrogen atom-containing groups"), and then by a hydrogenation step.

[0119] In the coupling process, it is preferable to perform a coupling reaction with a coupling agent having a nitrogen atom-containing group at one end of the active end of the conjugated diene polymer during polymerization.

[0120] Polymers coupled using a modifier containing nitrogen atoms exhibit good dispersibility of fillers such as silica and carbon black when combined with fillers to form a conjugated diene polymer composition (rubber composition). This results in good processability of the rubber composition and, when vulcanized, good abrasion resistance and fracture strength.

[0121] From the viewpoint of polymerization productivity and high modification rate, preferred coupling agents containing nitrogen atoms include isocyanate compounds, isothiocyanate compounds, isocyanuric acid derivatives, nitrogen group-containing carbonyl compounds, nitrogen group-containing vinyl compounds, nitrogen group-containing epoxy compounds, and nitrogen group-containing alkoxysilane compounds.

[0122] Furthermore, from the viewpoint of improving viscosity reduction of crosslinked products (e.g., crosslinked rubber compositions) obtained using the conjugated diene polymer of this embodiment and reducing crack occurrence in the compound sheet, a higher number of branches in the coupling agent is preferable. The number of branches in the coupling agent is not particularly limited, but from the viewpoint of improving processability, 3 or more branches are preferred, and 4 or more branches are more preferred. There is no particular upper limit to the number of branches, but from the viewpoint of productivity, 30 branches or less is preferred.

[0123] From the viewpoint of reactivity, preferred coupling agents containing nitrogen atoms include nitrogen-containing alkoxysilane compounds and nitrogen-containing polyfunctional modifiers.

[0124] The nitrogen-containing alkoxysilane compounds are not limited to the following, but include, for example, 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-silacycloheptane, and 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, 2-methoxy,2-methyl-1-(3-dimethoxymethylsilylpropyl)-1-aza-2-silacyclopentane, 2-E Toxy,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, tris(trimethoxysilylmethyl)amine, tris(2-trimethoxysilylethyl)amine, tris(4-trimethoxysilylbutyl)amine, tetrakis[3-(2,2-dimethoxy-1-a Examples include [2-silacyclopentane)propyl]-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane, and N-(3-(bis(3-(trimethoxysilyl)propyl)amino)propyl)-N-methyl-N'-(3-(methyl(3-(trimethoxysilyl)propyl)amino)propyl)-N'-(3-(trimethoxysilyl)propyl)-1,3-propanediamine.

[0125] Examples of nitrogen group-containing polyfunctional modifiers include, but are not limited to, compounds having one or more functional groups selected from epoxy groups, carbonyl groups, carboxylic acid ester groups, carboxylic acid amide groups, acid anhydride groups, phosphate ester groups, phosphite ester groups, epithio groups, thiocarbonyl groups, thiocarboxylic acid ester groups, dithiocarboxylic acid ester groups, thiocarboxylic acid amide groups, imino groups, ethyleneimino groups, halogen groups, alkoxysilyl groups, isocyanate groups, thioisocyanate groups, conjugated diene groups, and aryl vinyl groups, and having at least one nitrogen atom in the compound.

[0126] Furthermore, in calculating the number of moles of functional groups, each alkoxy group of epoxy, carbonyl, epithio, thiocarbonyl, imino, ethyleneimino, halogen, conjugated diene, aryl vinyl, and alkoxysilyl groups should be counted as 1 functional group, each carboxylic acid ester, carboxylic acid amide, acid anhydride, thiocarboxylic acid ester, dithiocarboxylic acid ester, thiocarboxylic acid amide, isocyanate, and thioisocyanate group should be counted as 2 functional groups, and each phosphate ester and phosphite ester group should be counted as 3 functional groups.

[0127] A polyfunctional modifier that can be preferably used to modify the conjugated diene polymer of this embodiment is one in which the sum of the number of functional groups in one molecule is 2 or more, and more preferably a polyfunctional modifier in which the sum of the number of functional groups is 3 or more.

[0128] When the hydrogenated conjugated diene polymer in this embodiment is a modified polymer, in addition to the coupling agent and modifying agent described above, polyfunctional modifying agents and coupling agents that do not contain nitrogen atoms, as described later, can also be used.

[0129] Polyfunctional modifiers include, but are not limited to, the following: polyglycidyl ethers of polyhydric alcohols such as ethylene glycol diglycidyl ether and glycerol triglycidyl ether; polyglycidyl ethers of aromatic compounds having two or more phenyl groups such as diglycidyl bisphenol A; polyepoxy compounds such as 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene, and polyepoxylated liquid polybutadiene; epoxy group-containing tertiary amines such as 4,4'-diglycidyl-diphenylmethylamine and 4,4'-diglycidyl-dibenzylmethylamine; diglycidyl Examples include glycidylamino compounds such as aniline, diglycidyl orthotoluidine, tetraglycidylmetoxydiamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, and tetraglycidyl-1,3-bisaminomethylcyclohexane; and compounds having epoxy groups and other functional groups such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltributoxysilane, epoxy-modified silicones, epoxidized soybean oil, and epoxidized linseed oil.

[0130] Furthermore, examples of coupling agents that do not contain nitrogen atoms include, but are not limited to, alkoxysilane compounds such as tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, and alkyltriphenoxysilane; halogenated silane compounds such as silicon tetrachloride, silicon tetrabromide, silicon tetraiodide, monomethyltrichlorosilicon, monoethyltrichlorosilicon, monobutyltrichlorosilicon, monohexyltrichlorosilicon, monomethyltribromosilicon, and bistrichlorosilylethane; and alkoxyhalogenated silane compounds such as monochlorotrimethoxysilane, monobromotrimethoxysilane, dichlorodimethoxysilane, dibromodimethoxysilane, trichloromethoxysilane, and tribromomethoxysilane.

[0131] Furthermore, examples of coupling agents that do not contain nitrogen atoms include tin halogenated compounds such as tin tetrachloride, tin tetrabromide, monomethyltrichlorotin, monoethyltrichlorotin, monobutyltrichlorotin, monophenyltrichlorotin, and bistrichlorostanylethane; polyhalogenated phosphorus compounds such as trichlorophosphine and tribromophosphine; phosphite ester compounds such as trisnonylphenyl phosphite, trimethyl phosphite, and triethyl phosphite; and phosphate ester compounds such as trimethyl phosphate and triethyl phosphate.

[0132] Furthermore, a terminal modifier may be used as the modifying agent for the conjugated diene polymer in this embodiment. Examples of terminal modifiers, but not limited to the following, include 1,3-diethyl-2-imidazolinone, 1,3-dimethyl-2-imidazolinone, 1,3-dipropyl-2-imidazolinone, 1-methyl-3-ethyl-2-imidazolinone, 1-methyl-3-propyl-2-imidazolinone, 1-methyl-3-butyl-2-imidazolinone, and 1,3-dihydro-1,3-dimethyl-2H-imidazole-2-one.

[0133] (Degeneration rate) In this specification, unless otherwise specified, "modification rate" refers to the mass ratio of copolymers having nitrogen atom-containing functional groups to the total amount of conjugated diene polymers.

[0134] For example, when a nitrogen atom-containing modifying agent is reacted with the terminal end of a polymer, the mass ratio of the polymer having nitrogen atom-containing functional groups due to the nitrogen atom-containing modifying agent to the total amount of the polymer is expressed as the modification rate.

[0135] On the other hand, when a polymer is branched using a branching agent containing nitrogen atoms, the resulting copolymer will also have nitrogen-containing functional groups, and therefore this branched polymer will also be counted when calculating the modification rate.

[0136] In other words, in this specification, a coupling polymer with a modifying agent having a nitrogen atom-containing functional group and / or a branched polymer with a branching agent having a nitrogen atom-containing functional group, wherein the total mass ratio of these is the "modification rate".

[0137] In this embodiment, the conjugated diene polymer preferably has a modification rate (hereinafter also simply referred to as "modification rate") of 5% to 99% of the total amount of the conjugated diene copolymer, as measured by column adsorption GPC. This is preferable from the viewpoint of balancing processability, wear resistance, fracture strength, and compression set.

[0138] The aforementioned rate of modification is more preferably 10% or more, even more preferably 20% or more, particularly preferably 30% or more, and especially preferably 40% or more. The upper limit of the aforementioned rate of modification is not particularly limited, but for example, it is 99% or less.

[0139] The denaturation rate can be measured, for example, by chromatography, which can separate denatured components containing functional groups from undenatured components.

[0140] One method using chromatography is to use a gel permeation chromatography column packed with a polar substance such as silica that adsorbs specific functional groups, and quantify the non-adsorbed components using an internal standard for comparison (column adsorption GPC method).

[0141] More specifically, the denaturation rate can be determined by measuring the amount adsorbed onto the silica column from the difference between the chromatogram measured on a polystyrene gel column and the chromatogram measured on a silica column for a sample solution containing the sample and a low molecular weight internal standard polystyrene.

[0142] More specifically, the rate of denaturation can be measured by the method described in the examples.

[0143] In the copolymer of this embodiment, the denaturation rate can be controlled, for example, by adjusting the amount of denaturing agent added and the reaction method, thereby being controlled to be between 5% and 99%.

[0144] For example, the above modification rate can be achieved by combining a polymerization method using an organolithium compound having at least one nitrogen atom in its molecule (described later) as a polymerization initiator, a copolymerization method using a monomer having at least one nitrogen atom in its molecule, and a structural formula modifier (described later), and by controlling the polymerization conditions.

[0145] [Method for producing conjugated diene polymers] The conjugated diene polymer of this embodiment is preferably obtained by carrying out a polymerization step using a predetermined polymerization initiator, preferably a coupling reaction step using the coupling agent described above, and then carrying out a hydrogenation step. More preferably, a branching step may be carried out using a branching agent before the coupling reaction step.

[0146] (Polymerization process) At least an organic monolithium compound can be used as the polymerization initiator in the polymerization process.

[0147] Examples of organic monolithium compounds include, but are not limited to, low-molecular-weight compounds and solubilized oligomeric organic monolithium compounds.

[0148] Furthermore, examples of organic monolithium compounds include compounds having a carbon-lithium bond, compounds having a nitrogen-lithium bond, and compounds having a tin-lithium bond, depending on the bonding mode between the organic group and its lithium.

[0149] The amount of organic monolithium compound used as a polymerization initiator is preferably determined by the target copolymer structure and molecular weight of the copolymer.

[0150] The amount of monomers used, such as conjugated diene compounds, relative to the amount of polymerization initiator used, is related to the degree of polymerization. In other words, it tends to be related to the number-average molecular weight and / or weight-average molecular weight.

[0151] Therefore, to increase the molecular weight, it is best to adjust the amount of polymerization initiator used to decrease it, and to decrease the molecular weight, it is best to adjust the amount of polymerization initiator used to increase it.

[0152] As for organic monolithium compounds, alkyllithium compounds having a substituted amino group, or dialkylaminolithium compounds, are preferred from the viewpoint that they can be used as a method for introducing nitrogen atoms into conjugated diene polymers.

[0153] In this case, a copolymer can be obtained having a nitrogen atom consisting of an amino group at the polymerization initiation end.

[0154] A substituted amino group is an amino group that either lacks active hydrogen or has a structure in which active hydrogen is protected.

[0155] Alkyl lithium compounds having an amino group that does not possess active hydrogen are not limited to the following, but examples include 3-dimethylaminopropyllithium, 3-diethylaminopropyllithium, 4-(methylpropylamino)butyllithium, and 4-hexamethyleneiminobutyllithium.

[0156] Alkyllithium compounds having an amino group with a structure that protects active hydrogen include, but are not limited to, 3-bistrimethylsilylaminopropyllithium and 4-trimethylsilylmethylaminobutyllithium.

[0157] Examples of dialkylaminolithium include, but are not limited to, lithium dimethylamide, lithium diethylamide, lithium dipropylamide, lithium dibutylamide, lithium di-n-hexylamide, lithium diheptylamide, lithium diisopropylamide, lithium dioctylamide, lithium di-2-ethylhexylamide, lithium didecylamide, lithium ethylpropylamide, lithium ethylbutylamide, lithium ethylbenzylamide, lithium methylphenethylamide, lithium hexamethyleneimide, lithium pyrrolidide, lithium piperidide, lithium heptamethyleneimide, lithium morpholide, 1-lithiazacyclooctane, 6-lithio-1,3,3-trimethyl-6-azabicyclo[3.2.1]octane, and 1-lithio-1,2,3,6-tetrahydropyridine.

[0158] These organomonolithium compounds having substituted amino groups can also be used as solubilized oligomeric organomonolithium compounds by reacting small amounts of polymerizable monomers, such as 1,3-butadiene, isoprene, and styrene.

[0159] From the viewpoint of ease of industrial availability and ease of control of polymerization reactions, alkyllithium compounds are preferred as organic monolithium compounds. In this case, copolymers having an alkyl group at the polymerization initiation end can be obtained.

[0160] The alkyllithium compound is not limited to the following, but examples include n-butyllithium, sec-butyllithium, tert-butyllithium, n-hexyllithium, benzyllithium, phenyllithium, and stilbenilithium.

[0161] As alkyllithium compounds, n-butyllithium and sec-butyllithium are preferred from the viewpoint of ease of industrial availability and ease of control of polymerization reactions.

[0162] These organic monolithium compounds may be used individually or in combination of two or more. They may also be used in combination with other organometallic compounds.

[0163] Examples of the aforementioned other organometallic compounds include alkaline earth metal compounds, other alkali metal compounds, and other organometallic compounds.

[0164] Examples of alkaline earth metal compounds include, but are not limited to, organomagnesium compounds, organocalcium compounds, and organostrontium compounds. Compounds of alkaline earth metal alkoxides, sulfonates, carbonates, and amides are also included.

[0165] Examples of organomagnesium compounds include dibutylmagnesium and ethylbutylmagnesium. Examples of other organometallic compounds include organoaluminum compounds.

[0166] In the polymerization process, the polymerization reaction mode is not limited to the following, but examples include batch mode (also called "batch reaction") and continuous polymerization reaction mode.

[0167] In a continuous reactor, one or more connected reactors can be used. Continuous reactors include, for example, tank-type or tubular-type reactors equipped with stirrers. Preferably, monomers, inert solvents, and polymerization initiators are continuously fed into the reactor, a polymer solution containing the polymer is obtained within the reactor, and the polymer solution is continuously discharged.

[0168] Batch reactors, for example, are tank-type reactors equipped with stirrers. In a batch reactor, monomers, an inert solvent, and a polymerization initiator are preferably fed into the reactor, and monomers are added continuously or intermittently during polymerization as needed, to obtain a polymer solution containing the polymer within the reactor, and the polymer solution is discharged after polymerization is complete.

[0169] In the method for producing conjugated diene polymers of this embodiment, a continuous process is preferred in order to obtain copolymers having a high proportion of active ends, which allows for the continuous discharge of the polymer and its subsequent reaction in a short amount of time.

[0170] The polymerization step of conjugated diene polymers is preferably carried out in an inert solvent. The solvent is not particularly limited, but examples include hydrocarbon solvents such as saturated hydrocarbons and aromatic hydrocarbons. Specific hydrocarbon solvents are not limited to the following, but examples include aliphatic hydrocarbons such as butane, pentane, hexane, and heptane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane, and methylcyclohexane; and hydrocarbons consisting of aromatic hydrocarbons such as benzene, toluene, and xylene, and mixtures thereof.

[0171] Treating the impurities, such as allenes and acetylenes, with organometallic compounds before the polymerization reaction tends to yield copolymers with a high concentration of active ends, and is therefore preferable because it tends to yield modified copolymers with a high degree of modification.

[0172] In the polymerization process, polar compounds (polar substances) may be added. Aromatic vinyl compounds can be randomly copolymerized with conjugated diene compounds, and they tend to be used as vinylizing agents to control the microstructure of the conjugated diene portion. They also tend to be effective in accelerating polymerization reactions.

[0173] Polar compounds include, but are not limited to, ethers such as tetrahydrofuran, diethyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, dimethoxybenzene, and 2,2-bis(2-oxolanyl)propane; tertiary amine compounds such as tetramethylethylenediamine, dipiperidinoethane, trimethylamine, triethylamine, pyridine, and quinuclidine; alkali metal alkoxide compounds such as potassium-tert-amylate, potassium-tert-butyrate, sodium-tert-butyrate, and sodium amylate; and phosphine compounds such as triphenylphosphine.

[0174] These polar compounds may be used individually or in combination of two or more.

[0175] The amount of polar compound used is not particularly limited and can be selected according to the purpose, but it is preferably 0.01 moles or more and 10 moles or less per mole of polymerization initiator.

[0176] Such polar compounds (vinylating agents) can be used in appropriate amounts depending on the desired amount of 1,2-vinyl bonds, as modifiers of the microstructure of the conjugated diene moiety in the polymer. Many polar compounds also have an effective randomization effect in copolymerization of conjugated diene compounds and aromatic vinyl compounds, and tend to be used as modifiers for adjusting the distribution of aromatic vinyl compounds and the amount of styrene block.

[0177] As a method for randomizing the conjugated diene compound and aromatic vinyl compound, for example, as described in Japanese Patent Publication No. 59-140211, a copolymerization reaction may be initiated with the entire amount of styrene and a portion of 1,3-butadiene, and the remaining 1,3-butadiene may be added intermittently during the copolymerization reaction.

[0178] The polymerization temperature in the polymerization process is preferably the temperature at which living anionic polymerization proceeds, and from the viewpoint of productivity, it is more preferably 0°C or higher, and even more preferably 120°C or lower. Within this range, it tends to be possible to ensure a sufficient amount of denaturing agent to react with the active ends after polymerization is complete. Even more preferably, it is 50°C to 100°C.

[0179] (Coupling process) The active ends of the copolymer obtained through the polymerization step described above, and optionally a branching step using a predetermined branching agent, are subjected to a coupling reaction with the aforementioned coupling agent or a modifying agent having a nitrogen atom-containing group.

[0180] (Inactivator addition process, neutralizing agent addition process) In the method for producing the conjugated diene polymer of this embodiment, after the coupling step, a deactivator, neutralizing agent, etc. may be added to the polymer solution as needed.

[0181] Inactivators are not limited to the following, but include, for example, water; and alcohols such as methanol, ethanol, and isopropanol.

[0182] Examples of neutralizing agents include, but are not limited to, carboxylic acids such as stearic acid, oleic acid, and versatic acid (a highly branched mixture of carboxylic acids with 9 to 11 carbon atoms, mainly around 10); aqueous solutions of inorganic acids; and carbon dioxide.

[0183] (Hydrogenation process) In the method for producing the conjugated diene polymer of this embodiment, the polymerization step described above may be performed, and optionally a branching step, a coupling step, and optionally a deactivator addition step, to carry out the hydrogenation reaction described above.

[0184] (Rubber stabilizer) In the method for producing the conjugated diene polymer of this embodiment, it is preferable to add a rubber stabilizer from the viewpoint of preventing gel formation after polymerization and improving stability during processing.

[0185] The rubber stabilizers are not limited to those listed below, but any known ones can be used. For example, 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)propinate, and 2-methyl-4,6-bis[(octylthio)methyl]phenol are preferred.

[0186] (Desolvation process) In the method for producing the conjugated diene polymer of this embodiment, known methods can be used to obtain the conjugated diene polymer from the polymer solution. The method is not particularly limited, but examples include a method in which the solvent is separated by steam stripping or the like, the polymer is filtered off, and then dehydrated and dried to obtain the polymer; a method in which the solution is concentrated in a flushing tank and then defolalated using a vent extruder or the like; and a method in which the solution is directly defolalated using a drum dryer or the like.

[0187] [Conjugated diene polymer composition] The conjugated diene polymer composition (rubber composition) of this embodiment contains 10 parts by mass or more of a filler per 100 parts by mass of the conjugated diene polymer of this embodiment described above, and the filler contains at least one of silica-based inorganic fillers, carbon black, and calcium carbonate. Preferably, the amount of filler is 150 parts by mass or less per 100 parts by mass of the conjugated diene polymer of this embodiment described above.

[0188] [Filler] The filler may contain at least one of the following: silica-based inorganic filler, carbon black, and calcium carbonate. These may be used individually or in combination of two or more. It may also contain fillers other than those mentioned above.

[0189] Also, from the viewpoints of strength and cost, the mass ratio of carbon black in the filler is preferably 30% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more.

[0190] From the viewpoint of exhibiting a reinforcing effect, the content of the filler in the conjugated diene polymer composition of the present embodiment is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, with respect to 100 parts by mass of the copolymer of the present embodiment described above. On the other hand, from the viewpoint of sufficiently dispersing the filler and making the processability and mechanical strength of the composition practically sufficient, it is preferably 150 parts by mass or less with respect to 100 parts by mass of the copolymer of the present embodiment described above.

[0191] The silica-based inorganic filler is not particularly limited, and known ones can be used. Solid particles containing SiO2 or Si3Al as a constituent unit are preferred, and solid particles containing SiO2 or Si3Al as a main component of the constituent unit are more preferred. Here, the main component refers to a component contained in the silica-based inorganic filler at 50% by mass or more, preferably 70% by mass or more, and more preferably 80% by mass or more.

[0192] Specific examples of the silica-based inorganic filler include, but are not limited to, the following: inorganic fibrous substances such as silica, clay, talc, mica, diatomaceous earth, wollastonite, montmorillonite, zeolite, and glass fiber. Also included are silica-based inorganic fillers with a hydrophobized surface and mixtures of silica-based inorganic fillers and inorganic fillers other than silica-based. Among these, silica and glass fiber are preferred from the viewpoints of strength and wear resistance, and silica is more preferred. Examples of silica include dry silica, wet silica, and synthetic silicate silica.

[0193] Examples of carbon black include, but are not limited to, carbon black of each class such as SRF, FEF, HAF, ISAF, and SAF. Among these, the nitrogen adsorption specific surface area is 50 m 2Carbon black with a concentration of 1 / g or more and a dibutyl phthalate (DBP) oil absorption of 80 mL / 100 g or less is preferred.

[0194] In the conjugated diene polymer composition of this embodiment, the carbon black content is preferably 5 to 150 parts by mass, more preferably 10 to 120 parts by mass, and even more preferably 15 to 100 parts by mass, per 100 parts by mass of the copolymer of this embodiment described above. The carbon black content within the above range is preferable in terms of breaking strength, compression set, and hardness.

[0195] While not particularly limited, examples of calcium carbonate include calcium carbonate with an average particle size of 0.04 μm to 8.0 μm and an oil absorption capacity of 10 to 35 g per 100 g of calcium carbonate.

[0196] Furthermore, the filler may also contain other fillers besides those mentioned above, such as metal oxides and metal hydrogenated compounds.

[0197] Metal oxides are those with the chemical formula M x O y This refers to solid particles whose main constituent unit is (where M represents a metal atom, and x and y each independently represent integers from 1 to 6).

[0198] Examples of metal oxides include, but are not limited to, alumina, titanium oxide, magnesium oxide, and zinc oxide.

[0199] Examples of metal hydroxides include, but are not limited to, aluminum hydroxide, magnesium hydroxide, and zirconium hydroxide.

[0200] The conjugated diene polymer composition (rubber composition) of this embodiment may contain a silane coupling agent. The silane coupling agent has the function of tightening the interaction between the rubber component and the inorganic filler, and has groups that have affinity or binding to the rubber component and the silica-based inorganic filler, respectively. Compounds having a sulfur bond moiety and an alkoxysilyl group or silanol group moiety in one molecule are preferred. Such compounds are not particularly limited, but examples include bis-[3-(triethoxysilyl)-propyl]-tetrasulfide, bis-[3-(triethoxysilyl)-propyl]-disulfide, and bis-[2-(triethoxysilyl)-ethyl]-tetrasulfide.

[0201] In the conjugated diene polymer composition of this embodiment, the content of the silane coupling agent is preferably 0.1 parts by mass to 30 parts by mass, more preferably 0.5 parts by mass to 20 parts by mass, and even more preferably 1.0 part by mass to 15 parts by mass, based on 100 parts by mass of the inorganic filler described above. When the content of the silane coupling agent is within the above range, the above-mentioned additive effect of the silane coupling agent tends to be made even more pronounced.

[0202] [Rubber softener]

[0203] The conjugated diene polymer composition of this embodiment may optionally contain a rubber softener. A rubber softener can be added as needed to further improve the productivity of the conjugated diene polymer and the processability when it is used in a composition containing fillers, etc.

[0204] Rubber softeners are not particularly limited, but examples include stretching oils, liquid rubber, and resins.

[0205] The method for adding a rubber softener to a conjugated diene polymer or conjugated diene polymer composition is not limited to the following, but a preferred method is to add the rubber softener to the copolymer solution, mix it to obtain a polymer solution containing the rubber softener, and then desolvate the resulting solution.

[0206] Preferred spreading oils include, for example, aromatic oils, naphthenic oils, and paraffinic oils. Among these, aromatic substitute oils with a polycyclic aromatic (PCA) component content of 3% by mass or less according to the IP346 method are preferred from the viewpoint of environmental safety, as well as from the viewpoint of preventing oil bleeding and improving wet grip characteristics. Examples of aromatic substitute oils include TDAE (Treated Distillate Aromatic Extracts) and MES (Mild Extraction Solvate) as shown in Kautschuk Gummi Kunststoffe 52(12)799(1999), as well as RAE (Residual Aromatic Extracts).

[0207] Preferred liquid rubbers are not limited to the following, but examples include liquid polybutadiene and liquid styrene-butazine rubber.

[0208] The effects of adding liquid rubber include improving the processability of conjugated diene polymer compositions, which are compounded with conjugated diene polymers and fillers, and also shifting the glass transition temperature of the conjugated diene polymer composition (rubber composition) to a lower temperature. This tends to improve the wear resistance, low hysteresis loss, and low-temperature properties of the vulcanized product.

[0209] Preferred resins include, but are not limited to, aromatic petroleum resins, coumarone-indene resins, terpene resins, rosin derivatives (including tung oil resins), tall oil, tall oil derivatives, rosin ester resins, natural and synthetic terpene resins, aliphatic hydrocarbon resins, aromatic hydrocarbon resins, mixed aliphatic-aromatic hydrocarbon resins, coumarin-indene resins, phenol resins, p-tert-butylphenol-acetylene resins, phenol-formaldehyde resins, xylene-formaldehyde resins, monoolefin oligomers, diolefin oligomers, aromatic hydrocarbon resins, aromatic petroleum resins, hydrogenated aromatic hydrocarbon resins, cyclic aliphatic hydrocarbon resins, hydrogenated hydrocarbon resins, hydrocarbon resins, hydrogenated tung oil resins, hydrogenated oil resins, and esters of hydrogenated oil resins with monofunctional or polyfunctional alcohols. These resins may be used individually or in combination of two or more. When hydrogenating, all unsaturated groups may be hydrogenated, or some may be left intact.

[0210] The effects of adding resin include improving the processability of conjugated diene polymer compositions (rubber compositions) when they are compounded with copolymers and fillers, improving the fracture strength when they are vulcanized, and shifting the glass transition temperature of the conjugated diene polymer composition (rubber composition) to a higher temperature, which tends to improve wet skid resistance.

[0211] The amount of rubber softener added, such as a stretching oil, liquid rubber, or resin, shall be 1 to 60 parts by mass per 100 parts by mass of the conjugated diene polymer of this embodiment, preferably 5 to 50 parts by mass, and more preferably 10 to 37.5 parts by mass.

[0212] When a rubber softener is added within the aforementioned range, the processability of the conjugated diene polymer composition (rubber composition) formed by blending the copolymer and fillers tends to be improved, and the fracture strength and abrasion resistance of the vulcanized product tend to be improved.

[0213] (Method for producing conjugated diene polymer compositions (rubber compositions))

[0214] Specific mixing methods for obtaining the conjugated diene polymer composition (rubber composition) of this embodiment are not limited to the following, but include, for example, a melt-kneading method using a general mixer such as an open roll, Banbury mixer, kneader, single-screw extruder, twin-screw extruder, or multi-screw extruder, and a method in which the solvent is removed by heating after dissolving and mixing each component.

[0215] Of these methods, melt-kneading methods using rolls, Banbury mixers, kneaders, and extruders are preferred from the viewpoint of productivity and good kneading performance. Furthermore, both methods of kneading the rubber components with other fillers, silane coupling agents, and additives in a single step, or methods of mixing in multiple steps, are applicable.

[0216] (Vulcanized composition)

[0217] The conjugated diene polymer composition (rubber composition) of this embodiment may be a vulcanized composition that has been subjected to vulcanization treatment with a vulcanizing agent.

[0218] The vulcanizing agents are not limited to the following, but include, for example, radical generators such as organic peroxides and azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur, and sulfur compounds.

[0219] Sulfur compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, high molecular weight polysulfur compounds, and the like. In the conjugated diene polymer composition (rubber composition) of this embodiment, the content of the vulcanizing agent is preferably 0.01 parts by mass or more and 20 parts by mass or less, and more preferably 0.1 parts by mass or more and 15 parts by mass or less, per 100 parts by mass of the rubber component. Conventional known methods can be applied as the vulcanization method, and the vulcanization temperature is preferably 120°C or more and 200°C or less, and more preferably 140°C or more and 180°C or less.

[0220] During vulcanization, a vulcanization accelerator may be used as needed.

[0221] Conventional known materials can be used as vulcanization accelerators, and are not limited to the following, but examples include sulfenamide-based, guanidine-based, thiuram-based, aldehyde-amine-based, aldehyde-ammonia-based, thiazole-based, thiourea-based, and dithiocarbamate-based vulcanization accelerators. Furthermore, vulcanization aids are not limited to the following, but examples include zinc oxide, stearic acid, and triallyl isocyanurate. The content of the vulcanization accelerator is preferably 0.01 parts by mass or more and 20 parts by mass or less, and more preferably 0.1 parts by mass or more and 15 parts by mass or less, per 100 parts by mass of the rubber component.

[0222] Examples of organic peroxides include 1,3-bis(tert-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexine-3, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexene-3, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 2,2'-bis(tert-butylperoxy)-p-isopropylbenzene, dicumyl peroxide, di-tert-butyl peroxide, tert-butyl peroxide, and p-menyl peroxide. Examples include tamper oxide, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, dilauroyl peroxide, diacetyl peroxide, tert-butylperoxybenzoate, 2,4-dichlorobenzoyl peroxide, p-chlorobenzoyl peroxide, benzoyl peroxide, di(tert-butylperoxy)perbenzoate, n-butyl-4,4-bis(tert-butylperoxy)valerate, and tert-butylperoxyisopropyl carbonate.

[0223] (Other additives) The conjugated diene polymer composition (rubber composition) of this embodiment may contain various additives other than those mentioned above, such as softeners and fillers, heat stabilizers, antistatic agents, weather stabilizers, anti-aging agents, colorants, and lubricants, to the extent that the purpose of this embodiment is not impaired.

[0224] Other known softening agents can be used.

[0225] Other fillers, while not particularly limited, include, for example, magnesium carbonate, aluminum sulfate, and barium sulfate. Known materials can be used as the heat stabilizer, antistatic agent, weather stabilizer, anti-aging agent, colorant, and lubricant.

[0226] [Uses of conjugated diene polymer crosslinked products (crosslinked rubber compositions)]

[0227] The conjugated diene polymer crosslinked product (crosslinked rubber composition) of this embodiment can be used as packing, gaskets, sealing materials, vibration-damping rubber, vibration isolation rubber, conveyor belts, shoe outsoles and shoe midsoles, automobile weatherstrips, glass runs, trunk lids, railway vehicle components, aircraft components, waterproof sheets, engine mounts, air springs, rubber gloves, medical and hygiene products, hoses for industrial and various applications, battery cases, adhesives, wire insulation, window frame rubber, rubber rolls, rubber rollers for office automation equipment and textiles, keypads, keyboard covers, swimming goggles, swimming caps, container bags, marine-related parts, interior flooring materials, artificial muscle materials, and materials for various industrial products. In these applications, various molded products can be obtained by molding the conjugated diene polymer crosslinked product (crosslinked rubber composition) of this embodiment. [Examples]

[0228] The embodiment will be described in more detail below with reference to specific polymerization examples, examples, and comparative examples, but this embodiment is not limited in any way to the polymerization examples, examples, and comparative examples described below.

[0229] The various physical properties in the polymerization examples, examples, and comparative examples were measured by the methods described below.

[0230] [Physical property measurement method] [Number of peaks] A GPC analyzer consisting of three columns packed with polystyrene gel was used to measure chromatograms, and the weight-average molecular weight (Mw) was determined based on a calibration curve using standard polystyrene. The specific measurement conditions are shown below. 20 μL of the following measurement solution was injected into the GPC analyzer and the measurement was performed.

[0231] (Measurement conditions) Device: Tosoh Corporation product name "HLC-8320GPC" Eluent: 5 mmol / L tetrahydrofuran (THF) containing triethylamine Guard column: Product name "TSKguardcolumn SuperH-H" manufactured by Tosoh Corporation. Separation column: A combination of TSKgel SuperH5000, TSKgel SuperH6000, and TSKgel SuperH7000, manufactured by Tosoh Corporation, linked together in that order. Oven temperature: 40℃ Flow rate: 0.6mL / min Detector: RI detector (product name "HLC8020" manufactured by Tosoh Corporation) Measurement solution: A measurement solution prepared by dissolving 10 mg of the sample in 20 mL of THF.

[0232] [Degeneration rate] The denaturation rate was measured using the column adsorption GPC method, taking advantage of the property that the denatured polymer is adsorbed onto the column, as follows. The amount of adsorption onto the silica-based column was determined by the difference between the chromatogram obtained by measuring the sample and a sample solution containing low molecular weight internal standard polystyrene on a column packed with polystyrene gel and the chromatogram obtained by measuring it on a column packed with silica gel, and the denaturation rate was calculated.

[0233] (GPC measurement conditions using polystyrene columns) The GPC measurement conditions using a polystyrene column are shown below. 20 μL of the measurement solution listed below was injected into the GPC measuring device and the measurement was performed. Device: Tosoh Corporation product name "HLC-8320GPC" Eluent: THF containing 5 mmol / L triethylamine Guard column: Product name "TSKguardcolumn SuperH-H" manufactured by Tosoh Corporation. Column: A combination of the product names "TSKgel SuperH5000", "TSKgel SuperH6000", and "TSKgel SuperH7000" manufactured by Tosoh Corporation, in that order. Oven temperature: 40℃ Flow rate: 0.6mL / min Detector: RI detector (Tosoh Corporation HLC8020) Measurement solution: 10 mg of the sample and 5 mg of standard polystyrene were dissolved in 20 mL of THF to prepare the sample solution.

[0234] (GPC measurement conditions using silica-based columns) The GPC measurement conditions using a silica-based column are shown below. 50 μL of the measurement solution listed below was injected into the GPC measuring device and the measurement was performed. Device: Tosoh Corporation product name "HLC-8320GPC" Eluent:THF Guard column: DIOL 4.6×12.5mm 5micron, manufactured by GL Sciences Co., Ltd. Separation column: Agilent Technologies' Zorbax PSM-1000S, PSM-300S, and PSM-60S columns linked together in that order. Oven temperature: 40℃ Flow rate: 0.5mL / min Detector: RI detector (Tosoh Corporation HLC8020)

[0235] (Method for calculating the degeneration rate): The denaturation rate (%) was calculated using the following formula, with the total peak area of ​​the chromatogram using a polystyrene column set to 100, the peak area of ​​the sample being P1, and the peak area of ​​standard polystyrene being P2. The total peak area of ​​the chromatogram using a silica column was also set to 100, with the peak area of ​​the sample being P3 and the peak area of ​​standard polystyrene being P4. Degeneration rate (%) = [1 - (P2 × P3) / (P1 × P4)] × 100 (However, P1+P2=P3+P4=100)

[0236] (Degeneration rate of peak (A)) The measurement was performed using the same method as described above for measuring the denaturation rate. Subsequently, the total peak area corresponding to peak (A) in the chromatogram using a polystyrene column was set to 100, the peak area of ​​the sample was set to P5, the peak area of ​​standard polystyrene to P6, and the total peak area corresponding to peak (A) in the chromatogram using a silica column was set to 100, the peak area of ​​the sample to P7, and the peak area of ​​standard polystyrene to P8. The denaturation rate (%) was then calculated using the following formula. Degeneration rate (%) = [1 - (P6 × P7) / (P5 × P8)] × 100 (However, P5+P6=P7+P8=100)

[0237] [Coupling rate] Similar to the weight-average molecular weight measurement method described above, a chromatogram was measured, and the coupling rate was calculated from the ratio of the peak area of ​​uncoupled (low molecular weight side peaks) to the peak area of ​​coupled (high molecular weight side peaks) peaks.

[0238] [Moony viscosity] Using a Mooney viscometer (product name "VR1132" manufactured by Ueshima Seisakusho Co., Ltd.), the Mooney viscosity and Mooney stress relaxation (relaxation rate) of each polymer were measured in accordance with JIS K6300 (ISO289-1) and ISO289-4. The measurement temperature was 100°C. Here, the sample was preheated for 1 minute, then the rotor was rotated at 2 rpm, and the torque was measured after 4 minutes to determine the Mooney viscosity (ML). (1+4) )

[0239] [Styrene content of the conjugated diene polymer before hydrogenation, and the molar ratio of each structural unit represented by the structural formulas (1) to (4) of the conjugated diene polymer, and the hydrogenation rate] 1The content of the aromatic vinyl monomer unit was calculated from the integrated value of the unsaturated bond part of the polymer before hydrogenation by 1H-NMR measurement. Subsequently, a large amount of methanol was added to the reaction solution after the hydrogenation reaction to precipitate and recover the polymer. Then, the polymer was extracted with acetone and vacuum dried. This was 1 used as a sample for 1H-NMR measurement to measure the hydrogenation rate. 1 The conditions for 1H-NMR measurement are described below.

[0240] (Measurement conditions) Measuring instrument: JNM-LA400 (manufactured by JEOL) Solvent: Deuterated chloroform Measurement sample: Extracted samples before and after hydrogenating the polymer Sample concentration: 50 mg / mL <000- 0885>Observation frequency: 400 MHz Chemical shift standard: TMS (tetramethylsilane) Pulse delay: 2.904 seconds Number of scans: 64 times Pulse width: 45° Measurement temperature: 26 °C

[0241] [Styrene block content] A chain in which 8 or more styrene structural units are consecutive was defined as a styrene block, and the styrene block content was determined as follows. From the 400 MHz 1H-NMR spectrum measured using deuterated chloroform as a solvent, 1 the ratio of the integrated values in each of the following chemical shift ranges of (X) was determined, and the content of the styrene block contained in each polymer was determined. (X) Aromatic vinyl compound chain of 8 or more: 6.00 ≤ S < 6.68

[0242] [Glass transition temperature] Using a conjugated diene polymer as a sample, measurements were carried out in accordance with ISO22768:2006. 10 mg of the sample was packed into a dedicated aluminum pan, and as the measuring device, a differential scanning calorimeter DSC7020 manufactured by Hitachi High-Technologies Science was used. It was heated from 30 °C to 160 °C at 20 °C / min and held for 2 minutes, then cooled from 160 °C to -120 °C at 10 °C / min, and then the DSC curve was recorded while heating from -120 °C to 160 °C at 10 °C / min. The peak top (Inflection point) of the DSC differential curve derived from the glass transition of the conjugated diene polymer when heating from -120 °C to 160 °C was taken as the glass transition temperature.

[0243] 〔Heat of crystallization〕 Using a conjugated diene polymer as a sample, measurements were carried out in accordance with ISO22768:2006. 10 mg of the sample was packed into a dedicated aluminum pan, and as the measuring device, a differential scanning calorimeter DSC7020 manufactured by Hitachi High-Technologies Science was used. It was heated from 30 °C to 160 °C at 20 °C / min and held for 2 minutes, then cooled from 160 °C to -120 °C at 10 °C / min, and then the DSC curve was recorded while heating from -120 °C to 160 °C at 10 °C / min. The heat of crystallization was determined from the peak area derived from the crystallization of the conjugated diene polymer when cooling from 160 °C to -120 °C.

[0244] 〔Peak top of tanδ of viscoelasticity〕 The dynamic viscoelastic spectrum was measured by the following method, and the peak top temperature of the loss tangent (tanδ) was determined. The device used was ARES manufactured by TA Instruments Co., Ltd. With a sample thickness of 2 mm, width of 10 mm, and length of 20 mm, under the conditions of strain (initial strain) of 0.15%, frequency of 1 Hz, measurement range from -100 °C to 120 °C, and heating rate of 3 °C / min, the peak top temperature of tanδ was measured.

[0245] 〔Metal content (silicon content)〕 The silicon content (in ppm) of the conjugated diene polymers obtained in the polymerization examples described later was measured by elemental analysis using inductively coupled plasma (ICP, manufactured by Shimadzu Corporation, instrument name: ICPS-8100).

[0246] (Precipitation from polymer solution during polymerization) When the conjugated diene polymer solutions of the examples and comparative examples described below are heated to 40°C, it is checked whether the polymer precipitates. If polymer precipitation occurs, a white olimer precipitate is observed. The presence of precipitation is indicated as "precipitation present," and the absence of precipitation is indicated as "no precipitation." From the viewpoint of productivity, such as preventing clogging during production, the absence of precipitation is necessary.

[0247] (Cold flow) A conjugated diene polymer was used as the sample for measurement. For cold flow measurement, a 40mm x 40mm x 50mm thick (H0) sample was subjected to a 1kg load at 25°C and left for 60 minutes. The percentage change in thickness (%) was calculated from the thickness (H60) using the following formula. Percentage change in thickness (%) = (H0 - H60) × 100 / H0

[0248] Furthermore, for Examples 1-18 and Comparative Examples 2-9, the results of Comparative Example 1 were indexed with 100. A smaller index indicates less cold flow in the rubber bale during storage, resulting in better handling. An index of 79 or less is very good (◎ in the table), 80-99 is practically acceptable (〇 in the table), and 100 or more is poor and practically problematic (× in the table). ◎ and 〇 indicate that an improvement in cold flow can be expected.

[0249] [Manufacturing of copolymers] (Preparation of hydrogenation catalyst) In the examples and comparative examples described later, the hydrogenation catalyst used in producing the copolymer was prepared by the following method.

[0250] A reaction vessel equipped with a stirring device was purged with nitrogen, and 1 liter of dried and purified cyclohexane was charged into it. Next, 100 mmol of bis(η5-cyclopentadienyl)titanium dichloride was added. While stirring thoroughly, an n-hexane solution containing 200 mmol of trimethylaluminum was added, and the reaction was carried out at room temperature for approximately 3 days. This yielded hydrogenation catalyst (T).

[0251] (Comparative Example 1) Conjugated diene polymer 1 As shown in Table 1, a temperature-controlled autoclave with an internal volume of 40 L, equipped with a stirrer and jacket, was used as the reactor. 2,880 g of 1,3-butadiene, 120 g of styrene, 21,000 g of cyclohexane, and 0.291 mol of tetrahydrofuran (THF) and 2.2 mmol of 2,2-bis(2-oxolanil)propane, which had been pre-treated to remove impurities, were added to the reactor, and the reactor temperature was maintained at 42°C. As a polymerization initiator, 14.9 mmol of n-butyllithium was supplied to the reactor. After the polymerization reaction began, the temperature inside the reactor rose due to the heat generated by polymerization, and the final temperature inside the reactor was 83°C. 14.9 mol of methanol was added to this polymer solution as a reaction stopper. To the obtained 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. Then, the conjugated diene polymer solution was removed dropwise by adding it to warm water, and the mixture was dried in a drying oven to obtain a composition of conjugated diene polymer 1 with added antioxidants. Table 3 shows the analytical results obtained by analyzing the conjugated diene polymer 1 using the method described above.

[0252] (Example 1) Conjugated diene polymer 2 As shown in Table 1, a temperature-controlled autoclave with an internal volume of 40 L, equipped with a stirrer and jacket, was used as the reactor. 2,880 g of 1,3-butadiene, 120 g of styrene, 21,000 g of cyclohexane, and 0.291 mol of tetrahydrofuran (THF) and 3.1 mmol of 2,2-bis(2-oxolanil)propane (BOP), which had been pre-treated to remove impurities, were added to the reactor, and the reactor temperature was maintained at 44°C. As a polymerization initiator, 23.8 mmol of n-butyllithium was supplied to the reactor. After the polymerization reaction began, the temperature inside the reactor rose due to the heat generated by polymerization, and the final temperature inside the reactor was 80°C. 23.8 mmol of methanol was added to this polymer solution as a reaction stopper. A portion of the conjugated diene polymer solution before hydrogenation was extracted and desolvent-removed in a dryer to obtain pre-hydrogenation conjugated diene polymer 2. Furthermore, the hydrogenation catalyst (TC) was added to the polymer solution before hydrogenation at a concentration of 50 ppm (Ti-based) per 100 parts by mass of the polymer before hydrogenation, and the mixture was reacted at a hydrogen pressure of 0.8 MPa and an average temperature of 85°C until the value of the predetermined formula (A) was reached. A portion of the conjugated diene polymer solution was withdrawn and desolvented in a dryer to obtain conjugated diene polymer 2. To the obtained 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. Then, the conjugated diene polymer solution was removed dropwise by adding it to warm water, and the mixture was dried in a drying oven to obtain a composition of conjugated diene polymer 2 with added antioxidants. Table 3 shows the analytical results obtained by analyzing the conjugated diene polymer 2 using the method described above.

[0253] (Comparative Example 2) Conjugated diene polymer 3 As shown in Table 1, a temperature-controlled autoclave with an internal volume of 40 L, equipped with a stirrer and jacket, was used as the reactor. 2,880 g of 1,3-butadiene, 120 g of styrene, 21,000 g of cyclohexane, and 0.291 mol of tetrahydrofuran (THF) and 2.2 mmol of 2,2-bis(2-oxolanil)propane (BOP), which had been pre-treated to remove impurities, were added to the reactor, and the reactor temperature was maintained at 43°C. As a polymerization initiator, 14.9 mmol of n-butyllithium was supplied to the reactor. After the polymerization reaction began, the temperature inside the reactor rose due to the heat generated by polymerization, and the final temperature inside the reactor was 78°C. To this polymer solution, 12.7 mmol of 1,3-dimethyl-2-imidazolidinone (compound 1) was added as a denaturing agent, and the reaction was allowed to proceed for 15 minutes. Subsequently, 14.9 mmol of methanol was added as a reaction stopper. A portion of the conjugated diene polymer solution before hydrogenation was extracted and desolvent-removed in a dryer to obtain the pre-hydrogenation conjugated diene polymer 3. The obtained conjugated diene polymer 3 was analyzed using the method described above. The analysis results are shown in Table 3.

[0254] Furthermore, the hydrogenation catalyst (TC) was added to the polymer solution before hydrogenation at a concentration of 50 ppm (Ti-based) per 100 parts by mass of the polymer before hydrogenation, and the mixture was reacted at a hydrogen pressure of 0.8 MPa and an average temperature of 85°C until the value of the predetermined formula (A) was reached. A portion of the conjugated diene polymer solution was withdrawn and desolvented in a dryer to obtain conjugated diene polymer 3. To the obtained 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. Then, the conjugated diene polymer solution was removed dropwise by adding it to warm water, and the mixture was dried in a drying oven to obtain a composition of conjugated diene polymer 3 with antioxidants added. Table 3 shows the analytical results obtained by analyzing the conjugated diene polymer 3 using the method described above.

[0255] (Comparative Example 3) Conjugated diene polymer 7 As shown in Table 1, referring to the polymerization conditions of Comparative Example 1, the styrene addition amount, butadiene addition amount, polymerization initiator addition amount, polar substance addition amount, type of modifier, modifier addition amount, reaction terminator addition amount, and polymerization temperature were each changed, and by not performing a hydrogenation reaction, a composition containing a conjugated diene polymer 7 and an antioxidant was obtained. Table 3 shows the analysis results of the obtained conjugated diene polymer 7 analyzed by the above method.

[0256] (Examples 2 to 15, Example 18, 37, 38, Comparative Examples 4 to 9, 19) Conjugated diene polymers 4 to 6, 8 to 18, 21 to 30 As shown in Tables 1 and 2, each conjugated diene polymer (conjugated diene polymers 4 to 6, 8 to 18, 21 to 30) was obtained in the same manner as in Comparative Example 2, except that the polymerization formulation was changed and the conditions of the hydrogenation reaction were adjusted. For Examples 2 to 4 and 11, 1,3 - dimethyl - 2 - imidazolidinone (Compound 1) was used as the modifier. For Examples 5 to 7, 9, 10, 12 to 14, 18, 37, 38, Comparative Examples 4 to 9, and 19, tetraglycidyl - 1,3 - bisaminomethylcyclohexane (Compound 2) was used as the modifier. On the other hand, for Examples 8 and 15, tetramethoxysilane (Compound 3) was used instead of the modifier.

[0257] After adding 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 as antioxidants to the solution of each obtained polymer, each conjugated diene polymer solution was dropped into warm water to remove the solvent, and then subjected to a drying treatment with a dryer to obtain a composition in which an antioxidant was added to each of the conjugated diene polymers (conjugated diene polymers 4 to 6, 8 to 18, 21 to 30). Table 3 or Table 4 shows the analysis results of the obtained conjugated diene polymers 4 to 6, 8 to 18, 21 to 30 analyzed by the above method.

[0258] (Examples 16 and 17) Conjugated diene polymers 19, 20 As shown in Table 2, each conjugated diene polymer (conjugated diene polymer 19, 20) was obtained in the same manner as in Comparative Example 2, except that the polymerization formulation was changed and the conditions of the hydrogenation reaction were adjusted. In Examples 16 and 17, two types of modifying agents were used during polymerization. The order of adding the modifying agents was as follows: in Example 16, compound 2 was added and reacted for 5 minutes, then compound 1 was added and reacted for 15 minutes. In Example 17, compound 4 was added and reacted for 5 minutes, then compound 1 was added and reacted for another 15 minutes. To the solution of each polymer obtained, 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, respectively. Then, the conjugated diene polymer solution was removed dropwise by adding it to warm water, and the mixture was dried in a drying oven to obtain compositions in which the conjugated diene polymers (conjugated diene polymers 19 and 20) had been given antioxidants. Table 4 shows the analytical results obtained by analyzing the conjugated diene polymers 19 and 20 using the method described above.

[0259] [Table 1]

[0260] [Table 2]

[0261] The types of activators listed in Tables 1 and 2 are as follows: Compound 1: 1,3-dimethyl-2-imidazolidinone Compound 2: Tetraglycidyl-1,3-bisaminomethylcyclohexane Compound 3: Tetramethoxysilane Compound 4: 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane

[0262] [Table 3]

[0263] [Table 4]

[0264] (Examples 19-36, 39-40, Comparative Examples 10-18, 20, and Reference Example 1) [Production of crosslinked conjugated diene polymers (rubber compositions)] Using the conjugated diene polymers 1 to 30 obtained in the examples and comparative examples, or EPDM (ethylene-propylene-diene copolymer: trade name "EP33" manufactured by JSR Corporation), as rubber component (A), rubber compositions containing each rubber component (A), carbon black (B), and crosslinking agent (C) were obtained according to the following compounding conditions and mixing method.

[0265] (Combination conditions) • Rubber component (A): 100 parts by mass The amounts of each compounding agent listed below are in parts by mass relative to 100 parts by mass of rubber component (A) that does not contain rubber softeners. • Carbon black (product name "Seas KH (N550)" manufactured by Tokai Carbon Co., Ltd.): 70 parts by mass • Anti-aging agent 1 (product name "Nocrack MB" manufactured by Ouchi Shinko Chemical Co., Ltd.): 1.0 parts by mass • Anti-aging agent 2 (product name "Nocrack CD" manufactured by Ouchi Shinko Chemical Co., Ltd.): 1.0 part by mass • Naphthenic oil: 10 parts by mass Stearic acid: 1.0 part by mass • Organic peroxide (dicumyl peroxide): 3.0 parts by mass

[0266] <Mixing method> The above materials were kneaded by the following method to obtain a rubber composition. Using a sealed kneader (capacity 0.3L) equipped with a temperature control device, the first stage of kneading involved mixing rubber components, filler (carbon black), naphthenic oil, antioxidants 1 and 2, and stearic acid under conditions of a filling rate of 65% and a rotor rotation speed of 30-50 rpm. At this time, the temperature of the sealed mixer was controlled, and the first stage of the mixture was obtained with a discharge temperature of 125-130°C. After cooling, the mixture was kneaded in a second stage using an open roll oven set to 70°C, with organic peroxide added. The mixture was then molded and vulcanized in a vulcanizing press at 160°C for 20 minutes. The rubber composition before vulcanization and the crosslinked rubber composition after vulcanization were evaluated.

[0267] Specifically, the evaluation was performed using the following method. The results are shown in Tables 5 and 6.

[0268] (Evaluation of the physical properties of the compound) The Mooney viscosity of the rubber composition before vulcanization, and the tensile strength, tensile elongation, compression set, ozone resistance, and cold resistance of the cross-linked rubber composition were measured as follows.

[0269] <Moony viscosity of rubber composition> In accordance with JIS K6300 (ISO289-1) and ISO289-4, the Mooney viscosity of the rubber composition before vulcanization was measured and used as an indicator of processability. The measurement temperature was set to 100°C. First, the sample was preheated for 1 minute, then the rotor was rotated at 2 rpm, and the torque was measured after 4 minutes to determine the Mooney viscosity (ML). (1+4) The measurement instrument used was a Mooney viscometer (product name "VR1132" manufactured by Ueshima Seisakusho Co., Ltd.). The viscosity of the composition (ML) should be 160 or less to suppress the cohesiveness and tearing of the compound dough, and from the viewpoint of improving productivity, it is practically acceptable if it is 150 or less, and more preferably 145 or less. On the other hand, from the viewpoint of suppressing adhesion, it is practically acceptable if it is 40 or more, 50 or more is preferred, and more preferably 60 or more.

[0270] <Tensile strength, tensile elongation> The tensile strength and tensile elongation of the cross-linked rubber composition after vulcanization were measured in accordance with the tensile testing method of JIS K6251. The measuring instrument used was the AUTOGRAPH AGS-X manufactured by Shimadzu Corporation. The tensile strength is preferably 12 MPa or higher, more preferably 13 MPa or higher, and even more preferably 15 MPa or higher. The tensile elongation is preferably 410% or more, more preferably 420% or more, and even more preferably 430% or more, from the viewpoint of preventing chipping of the cross-linked rubber.

[0271] <Low-temperature elastic recovery test> In accordance with JIS K6261:2006, which corresponds to ISO2921, the TR10 value was measured in a low-temperature elastic recovery test of cross-linked rubber and used as an indicator of cold resistance. If the TR10 value is less than -50°C, there will be no problem using it in cold regions. Preferably, it is -55°C or lower, more preferably -57°C or lower, and particularly preferably -60°C or lower. Furthermore, based on the test conditions, if the recovery rate was 10% or more at the start of the test at -70°C, the value of TR10 was recorded as -70°C.

[0272] <Compression permanent strain> In accordance with JIS K6262, the compression set of the crosslinked rubber composition was measured after heating at 100°C for 72 hours. From the viewpoint of ensuring the physical stability and preventing distortion during long-term use of cross-linked rubber, a compression set of 45 or less is practically acceptable, 30 or less is preferable, and 25 or less is even more preferable.

[0273] <Heat resistance> The punched cross-linked rubber composition used for measuring tensile strength, etc., was heated at 100°C for 72 hours under normal pressure and air. After heating, the cross-linked rubber composition was subjected to tensile strength and tensile elongation measurements in accordance with the tensile test method of JIS K6251. The product of the tensile strength and tensile elongation of the cross-linked rubber composition after heating was calculated, with the product of the tensile strength and tensile elongation of the unheated cross-linked rubber composition set to 100. Regarding heat resistance, a higher numerical value indicates less deterioration due to heating and superior heat resistance, while a lower numerical value indicates greater deterioration due to heating and inferior heat resistance. A value between 95 and 105 indicates excellent heat resistance, a value between 90 and 95 or between 110 and 115 indicates sufficient heat resistance for practical use, and a value below 90 or above 115 indicates poor heat resistance.

[0274] <Ozone resistance> Measurements were performed in accordance with the static ozone degradation test described in JIS K6259-1 (2015). The measurement samples used were cross-linked rubber compositions punched out into a 2mm thick, 25mm x 115mm size (No. 5 dumbbell shape). The test conditions were 40°C, ozone concentration of 50 pphm, and irradiation times of 24, 48, and 96 hours. Samples were taken at each time point, and if no cracks of 0.5mm or larger were found, the evaluation was continued (marked with "○"). Conversely, if one or more cracks of 0.5mm or larger were found, the evaluation was stopped (marked with "×"). If no cracks are present after 24 hours, it is practically usable; it is preferable that no cracks are present after 48 hours; and if no cracks are present after 96 hours, it has excellent ozone resistance.

[0275] [Table 5]

[0276] [Table 6]

[0277] The conjugated diene polymers obtained in Examples 1-18, 37, and 38, and the conjugated diene polymer compositions and crosslinked conjugated diene polymers of Examples 19-36 and 39-40, were found to have sufficient heat resistance for practical use, while maintaining processability, and exhibiting superior compression set and low-temperature properties compared to the conjugated diene polymers obtained in Comparative Examples 1-9 and 19, and the conjugated diene polymer compositions and crosslinked conjugated diene polymers of Comparative Examples 10-18 and 20. [Industrial applicability]

[0278] The conjugated diene polymer, conjugated diene polymer composition, and conjugated diene polymer crosslinked products of the present invention have industrial potential as packing and gaskets, sealing materials, vibration-damping rubber, vibration isolation rubber, vibration damping materials, conveyor belts, shoe outsoles and shoe midsoles, automobile weatherstrips, glass runs, trunk lids, railway vehicle components, aircraft components, waterproof sheets, engine mounts, air springs, rubber gloves, medical and hygiene products, industrial and various application hoses, battery cases, adhesives, wire insulation, window frame rubber, rubber rollers for office automation equipment and textiles, keypads, keyboard covers, swimming goggles, swimming caps, container bags, marine-related parts, interior flooring materials, artificial muscle materials, and materials for various industrial products.

Claims

1. The following structural formulas (1) to (4); 【Chemistry 1】 When the constituent molar ratios of each structural unit represented by are a, b, c, and d, The following formula (A); Formula (A): 35(%)≦100*(b+d) / (a+b+c+d)≦90(%) Satisfying the conditions, The Mooney viscosity at 100°C is between 25 and 125. The glass transition temperature measured by differential calorimetry (DSC) is -60°C or lower, and the heat of crystallization derived from the crystallization peak is 2.5 J / g or more and 50 J / g or less. Conjugated diene polymers.

2. Contains aromatic vinyl monomer units in an amount of 1.0% to 8.0% by mass. The conjugated diene polymer according to claim 1.

3. The following formula (B); Formula (B): 90 (%) ≤ 100 * b / (a ​​+ b) Satisfying The conjugated diene polymer according to claim 1.

4. The following formula (C); Formula (C): 100*(a+b) / (a+b+c+d)<40(%) Satisfying The conjugated diene polymer according to claim 1.

5. In the molecular weight distribution curve obtained by gel permeation chromatography (GPC), there are at least two peaks. When the total area of ​​the molecular weight distribution curve is set to 100%, the area ratio of the peak with the highest molecular weight (B) among the peaks is 10% or more and 70% or less. The conjugated diene polymer according to claim 1.

6. In the molecular weight distribution curve obtained by gel permeation chromatography (GPC), there are at least two peaks. The mass ratio of the modified polymer in the polymer contained in the lowest molecular weight peak (A) among the aforementioned peaks is 50% or more. The conjugated diene polymer according to claim 1.

7. The degeneration rate is between 5% and 99%. The conjugated diene polymer according to claim 1.

8. The tanδ peak top of the viscoelasticity is between -85°C and -40°C. The conjugated diene polymer according to claim 1.

9. The above formula (A) is 50% or more. The conjugated diene polymer according to claim 1.

10. The silicon content is 100 ppm or less. The conjugated diene polymer according to claim 1.

11. A compound comprising 100 parts by mass of a conjugated diene polymer according to any one of claims 1 to 10 and 10 parts by mass or more of a filler, The filler comprises one or more selected from the group consisting of silica-based inorganic fillers, carbon black, and calcium carbonate. A conjugated diene polymer composition.

12. The filler contains at least the carbon black, The mass percentage of carbon black contained in the filler is 30% by mass or more. The conjugated diene polymer composition according to claim 11.

13. A vulcanization composition comprising the conjugated diene polymer composition described in Claim 11 and an organic peroxide, Conjugated diene polymer crosslinked product.

Images