Polymer composition and method for producing the same, as well as rubber composition and tire

Abstract

To provide: a polymer composition which exhibits excellent cold flow resistance; a method for producing the same; a rubber composition containing the polymer composition; and a tire obtained using the rubber composition.SOLUTION: A polymer composition contains a diene-based polymer having a number average molecular weight of 500,000 g / mol or more, and a resin having a value of %H Ar of 20% or more and a softening point of 110°C or more. The content of the resin is 20 pts.mass or more relative to 100 pts.mass of the diene-based polymer.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to a polymer composition and a method for producing the same, as well as a rubber composition and a tire. [Background technology]

[0002] Polymers used in tire manufacturing can have relatively high molecular weights to meet various performance requirements. In such cases, oil-added polymers, to which processing oils are added, are sometimes used to improve processability. Furthermore, polymers with added resins are sometimes used to achieve both improved tire grip performance and processability. For example, Patent Document 1 discloses a technique in which the tackiness of a composition is reduced by using a polymer to which a specific resin has been added. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Special Publication No. 2020-528487 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] However, polymers to which oil or resin has been added, as exemplified in Patent Document 1, tend to exhibit a significant cold flow phenomenon, and improvements from this perspective have been sought. The present invention aims to provide a polymer composition with excellent cold flow resistance, a method for producing the same, a rubber composition containing the polymer composition, and a tire using the rubber composition, and aims to solve this problem. [Means for solving the problem]

[0005] <1> A diene polymer having a number-average molecular weight of 500,000 g / mol or more, A resin with a %H Ar value of 20% or more and a softening point of 110°C or higher. A polymer composition containing the above, wherein the content of the resin is 20 parts by mass or more per 100 parts by mass of the diene polymer.

[0006] <2> The diene polymer includes styrene-butadiene copolymer rubber. <1> Polymer formulation described below <3> The glass transition temperature of the diene polymer is -30°C or lower. <1> or <2> The polymer composition described above. <4> The aforementioned diene polymer is modified. <1> ~ <3> A polymer composition as described in any one of the following.

[0007] <5> The aforementioned resin includes one or more selected from the group consisting of C9 resins and terpene-aromatic compound resins. <1> ~ <4> A polymer composition as described in any one of the following. <6> The resin comprises one or more selected from the group consisting of styrene monomer monopolymer resins and terpene phenol resins. <5> The polymer composition described above. <7> The glass transition temperature of the resin is 65°C or higher. <1> ~ <6> A polymer composition as described in any one of the following. <8> The number-average molecular weight of the aforementioned resin is 300 g / mol or more. <1> ~ <7> A polymer composition as described in any one of the following.

[0008] <9> The glass transition temperature of the diene polymer is -60°C or lower. <3> The polymer composition described above.

[0009] <10> The oil content is 0% by mass. <1> ~ <9> A polymer composition as described in any one of the following.

[0010] <11> A diene polymer having a number-average molecular weight of 500,000 g / mol or more, A resin with a %H Ar value of 20% or more and a softening point of 110°C or higher. A method for producing a polymer composition, comprising mixing the following, wherein the amount of the resin is 20 parts by mass or more per 100 parts by mass of the diene polymer.

[0011] <12> A rubber composition containing the polymer composition according to any one of <1> to <10>. <13> A tire using the rubber composition according to <12>.

Advantages of the Invention

[0012] According to the present invention, it is possible to provide a polymer composition excellent in cold flow resistance, a method for producing the same, a rubber composition containing the polymer composition, and a tire using the rubber composition.

Embodiments for Carrying Out the Invention

[0013] <Polymer Composition> The polymer composition in the present invention contains a diene polymer having a number average molecular weight of 500,000 g / mol or more and a resin having a %H Ar value of 20% or more and a softening point of 110°C or more, and the content of the resin is 20 parts by mass or more with respect to 100 parts by mass of the diene polymer. Hereinafter, the "diene polymer having a number average molecular weight of 500,000 g / mol or more" may be referred to as the "diene polymer in the present invention"; and the "resin having a %H Ar value of 20% or more and a softening point of 110°C or more" may be referred to as the "resin in the present invention".

[0014] Conventionally, as represented by oil-extended styrene-butadiene copolymer rubber (oil-extended SBR) or the like, in a rigid diene polymer having a number average molecular weight of 500,000 g / mol or more, oil or the like may be mixed as a plasticizer from the viewpoint of improving the processability of the polymer. However, when the diene polymer mixed with oil or the like is processed into, for example, a sheet shape or a block shape and stacked and stored, the diene polymer is deformed and a phenomenon of flowing (cold flow phenomenon) is likely to occur. On the other hand, the polymer composition of the present invention is excellent in cold flow resistance. Although the reason for this is not clear, it is presumed to be due to the following reasons.

[0015] Since the resin in the present invention has a %H Ar value of 20% or more and a softening point of 110°C or more, it has low compatibility with a diene polymer having a number average molecular weight of 500,000 g / mol or more and has rigidity. Therefore, the resin in the present invention is considered to act like a filler that is difficult to relax in the diene polymer in the present invention. As a result, it is considered that deformation of the polymer composition can be suppressed and the cold flow phenomenon can be suppressed. Hereinafter, the constituent components of the polymer composition will be described in detail.

[0016] 〔Diene polymer〕 The diene polymer in the present invention has a number average molecular weight of 500,000 g / mol or more. Hereinafter, the last three digits ",000" of the molecular weight may be represented by "k", and 500,000 may be described as "500k". In the present invention, the number average molecular weight (Mn) means the polystyrene-converted number average molecular weight measured by GPC (gel permeation chromatography). The number average molecular weight of the diene polymer preferably exceeds 500,000 (500k) g / mol, more preferably is 1,000,000 (1000k) g / mol or more, and still more preferably is 1,250,000 (1250k) g / mol or more. Also, the number average molecular weight of the diene polymer is preferably 3,000,000 (3000k) g / mol or less, more preferably 2,500,000 (2500k) g / mol or less, and still more preferably 2,000,00,000 (2000k) g / mol or less.

[0017] From the viewpoint of further improving the rolling resistance and WET performance balance of a tire obtained from a rubber composition containing the polymer composition of the present invention, the glass transition temperature (Tg) of the diene polymer is preferably -30°C or lower, more preferably -45°C or lower, still more preferably -60°C or lower, and also preferably -80°C or higher. The Tg of the diene polymer can be measured by a differential scanning calorimeter (DSC).

[0018] It is preferable that the diene polymer is modified. In other words, it is preferable that the diene polymer has a modified functional group in its molecular chain. By modifying the diene polymer, when the rubber composition containing the polymer composition of the present invention contains a filler, the filler dispersibility is improved, and a vulcanized rubber with low heat generation can be obtained. Diene polymers can be modified with modifying agents such as alkoxysilane compounds, amine compounds, and tin compounds. One or more modifying agents may be used. By using these modifying agents, the diene polymer can have modified functional groups in its molecular chain, such as alkoxysilane groups, primary, secondary, or tertiary amino groups, and tin atom-containing groups. Furthermore, primary and secondary amino groups may be protected with hydrolyzable protecting groups. The modified functional groups in the diene polymer may be one or more. In particular, it is preferable that the diene polymer has at least alkoxysilane groups in its molecular chain, and more preferably amino groups in addition.

[0019] Examples of diene polymers include polyisoprene rubber (IR), styrene-butadiene copolymer rubber (SBR), butadiene polymer (BR), ethylene-propylene-diene rubber (EPDM), chloroprene rubber (CR), halogenated butyl rubber, and acrylonitrile-butadiene rubber (NBR). SBR, BR, and IR may also be hydrogenated. Diene polymers may be used individually or in combination of two or more types. Among the above, the diene polymer in the present invention preferably contains styrene-butadiene copolymer rubber (SBR), and more preferably consists of styrene-butadiene copolymer rubber (SBR).

[0020] The amount of vinyl bond (Vi) in the diene compound portion of the diene polymer is preferably 10 to 70 mol%, more preferably 15 to 60 mol%, and more preferably 20 to 50 mol%, from the viewpoint of balancing the rolling resistance and wet performance of the tire obtained from the rubber composition containing the polymer composition of the present invention. Furthermore, the amount of vinyl bond in the diene polymer is 1 It can be measured by 1H-NMR spectroscopy.

[0021] When using modified or unmodified SBR as the diene polymer, the amount of bound styrene (St) of the modified or unmodified SBR is preferably 3 to 25 mol%, more preferably 4 to 22 mol%, and even more preferably 5 to 18 mol%, from the viewpoint of low loss and wet performance of the tire obtained from the rubber composition containing the polymer composition of the present invention. The amount of bound styrene in modified or unmodified SBR is 1 It can be measured by 1H-NMR spectroscopy.

[0022] 〔resin〕 The polymer composition contains a resin (the resin in this invention) with a %H Ar value of 20% or more and a softening point of 110°C or higher, and the content of the resin in this invention in the polymer composition is 20 parts by mass or more per 100 parts by mass of the diene polymer. If the content of the resin according to the present invention in the polymer composition is less than 20 parts by mass per 100 parts by mass of the diene polymer, the cold flow phenomenon of the polymer composition cannot be suppressed. From the viewpoint of further improving the cold flow resistance of the polymer composition, the content of the resin according to the present invention in the polymer composition is preferably 30 parts by mass or more, more preferably 35 parts by mass or more, and even more preferably 50 parts by mass or more, per 100 parts by mass of the diene polymer. The content of the resin in the polymer composition according to the present invention is preferably 100 parts by mass or less, more preferably 80 parts by mass or less, and even more preferably 70 parts by mass or less, per 100 parts by mass of the diene polymer.

[0023] (%H Ar value) The %H Ar value represents the amount of hydrogen atoms (H) [%] bonded to the aromatic ring (Ar) in a compound, and indicates the degree of polarity from the perspective of the resin's structure. It can be calculated using the following formula when the hydrogen atoms contained in the resin are separated into aromatic and non-aromatic origins. %H Ar value = [Amount of hydrogen atoms from aromatic sources / (Amount of hydrogen atoms from aromatic sources + Amount of hydrogen atoms from non-aromatic sources)] × 100

[0024] A high %H Ar value indicates high polarity and poor compatibility with diene polymers with a number-average molecular weight of 500,000 g / mol or more. A low %H Ar value indicates low polarity and high compatibility with diene polymers with a number-average molecular weight of 500,000 g / mol or more. The resin in this invention has a %H Ar value of 20% or more, and therefore has low compatibility with diene polymers having a number average molecular weight of 500,000 g / mol or more. In the present invention, a higher %H Ar value of the resin indicates lower and better compatibility with diene polymers, with a value of 25% or more being preferred, and more preferably 30% or more. Furthermore, the %H Ar value of the resin in the present invention is preferably 62.5% or less.

[0025] The %H Ar value can be measured as follows: 20 mg ± 1 mg of resin was dissolved in 0.7 mL of CDCl3 with 100% deuterated resin, and NMR was performed using a Bruker 500 MHz NMR spectrometer at 25°C with 32 scans. 1 Measure the 1H NMR spectrum. The signal of the internal standard [Si(CH3)3]O is set to 0 ppm, and %H Ar is calculated as [(integral value from 8.5 to 6.2 ppm) / (integral value from 8.5 to 0 ppm)] × 100.

[0026] While the SP (Solubility Parameter) value is sometimes used to represent the compatibility between polymers and resins, the SP value cannot be calculated if the molecular structure of the resin is unknown. On the other hand, the %H Ar value is an indicator of the aromatic components that are important for the compatibility between diene polymers and resins, and can express compatibility even when the detailed molecular structure is unknown.

[0027] (softening point) The resin in this invention has a softening point (Ts) of 110°C or higher. In this invention, the resin has a softening point of 110°C or higher, which imparts rigidity to the polymer composition, suppresses deformation of the polymer composition, and suppresses the cold flow phenomenon. The softening point of the resin in the present invention is preferably 115°C or higher, and more preferably 120°C or higher. Furthermore, from the viewpoint of processability of the polymer composition, the softening point of the resin in the present invention is preferably 150°C or lower, more preferably 145°C or lower, and even more preferably 140°C or lower. The softening point can be measured by a method compliant with JIS-K2207-1996 (ring-sphere method).

[0028] The resin in this invention is not particularly limited as long as it has a %H Ar value of 20% or more and a softening point of 110°C or higher. Examples include C5-C9 resins, C9 resins, terpene-aromatic compound resins, DCPD-aromatic compound resins, and the like. In this invention, only one type of resin may be used, or two or more types may be used. In particular, C9 resins and terpene-aromatic compound resins are preferred from the viewpoint of achieving both a high %H Ar value and a softening point, while styrene monomer monopolymer resins and terpene phenol resins are preferred.

[0029] C9 resins refer to solid polymers obtained by polymerizing a C9 fraction using a Friedel-Crafts type catalyst such as AlCl3 or BF3. Examples of C9 resins include (co)polymers mainly composed of indene, α-methylstyrene, vinyltoluene, etc. The C9 resin preferably contains a styrene monomer monopolymer resin, and examples of styrene monomer monopolymer resins include polystyrene, α-methylstyrene resin, vinyltoluene resin, and α-methylvinyltoluene resin. Polystyrene and α-methylstyrene resin are preferred as the styrene monomer monopolymer resin.

[0030] A typical example of terpene-aromatic compound resins is terpene-phenol resin. These terpene-phenol resins can be obtained by reacting terpenes with various phenols using a Friedel-Crafts type catalyst, or by further condensation with formalin. There are no particular restrictions on the terpenes used as raw materials, but monoterpene hydrocarbons such as α-pinene and limonene are preferred, those containing α-pinene are more preferred, and α-pinene is particularly preferred. The skeleton may also contain styrene or the like.

[0031] In the present invention, the resin preferably has a glass transition temperature of 65°C or higher, and more preferably 70°C or higher, from the viewpoint of further suppressing deformation of the polymer composition. Furthermore, from the viewpoint of cold flow resistance, the glass transition temperature of the resin in the present invention is preferably 100°C or lower, more preferably 97°C or lower, and even more preferably 93°C or lower. Furthermore, the glass transition temperature of the resin in this invention can be measured using a differential scanning calorimetry (DSC).

[0032] In the present invention, the resin preferably has a number-average molecular weight (Mn) of 300 g / mol or more. Having a number-average molecular weight of 300 g / mol or more in the present invention reduces the compatibility of the resin with diene polymers. In this invention, the number-average molecular weight (Mn) of the resin refers to the polystyrene-equivalent number-average molecular weight measured by GPC (gel permeation chromatography). The number-average molecular weight of the resin in the present invention is more preferably 500 g / mol or more, and even more preferably 600 g / mol or more. Furthermore, the number-average molecular weight of the resin in the present invention is preferably 1000 g / mol or less, more preferably 950 g / mol or less, and even more preferably 900 g / mol or less.

[0033] In the present invention, the weight-average molecular weight (Mw) of the resin is preferably 1000 to 2000 g / mol, more preferably 1200 to 1900 g / mol, and even more preferably 1400 to 1800 g / mol, from the viewpoint of compatibility with diene polymers. Weight-average molecular weight (Mw) refers to the weight-average molecular weight on a polystyrene basis, measured by GPC (gel permeation chromatography).

[0034] In the present invention, the molecular weight distribution (MWD) of the resin is preferably 1.30 to 2.50, more preferably 1.40 to 2.40, and even more preferably 1.50 to 2.30, from the viewpoint of compatibility with diene polymers. In this invention, the molecular weight distribution (MWD) of the resin can be calculated from the ratio (Mw / Mn) of the weight-average molecular weight (Mw) to the log-average molecular weight (Mn).

[0035] As described above, by including the diene polymer and a predetermined amount of the resin according to the present invention in the polymer composition, the glass transition temperature of the polymer composition can be increased or incompatible high-Tg domains can be created, thereby suppressing the cold flow phenomenon. The glass transition temperature of the polymer composition can be measured using a differential scanning calorimetry (DSC).

[0036] The polymer composition may further contain components other than the diene polymer and resin of the present invention, but it is preferable that it does not contain oil. That is, it is preferable that the oil content in the polymer composition is 0% by mass. The absence of oil in the polymer composition makes it easier to maintain the rigidity of the polymer composition. Here, "oil" refers to a softening agent that is liquid at 25°C, such as mineral oils like process oils, or vegetable oils. From the viewpoint of further improving the cold flow resistance of the polymer composition, it is preferable that the polymer composition consists of the diene polymer and the resin according to the present invention.

[0037] <Method for producing polymer compositions> This method involves mixing a diene polymer having a number-average molecular weight of 500,000 g / mol or more with a resin having a %H Ar value of 20% or more and a softening point of 110°C or higher, wherein the amount of the resin blended is 20 parts by mass or more per 100 parts by mass of the diene polymer. The diene polymer having a number-average molecular weight of 500,000 g / mol or more can be the polymer described as the diene polymer in this invention, and the preferred embodiment is the same. Furthermore, the resin having a %H Ar value of 20% or more and a softening point of 110°C or higher can be the resin described as the resin in this invention, and the preferred embodiment is the same. In the present invention, the amount of resin blended is preferably 30 parts by mass or more, more preferably 35 parts by mass or more, and even more preferably 50 parts by mass or more, per 100 parts by mass of the diene polymer, from the viewpoint of further improving the cold flow resistance of the polymer composition produced.

[0038] <Rubber composition> The rubber composition of the present invention comprises the polymer composition of the present invention. The rubber composition of the present invention may contain diene rubbers such as natural rubber, isoprene rubber, and butadiene rubber as rubber components. When the diene polymer in the present invention is a diene polymer, the polymer composition of the present invention can be used as the rubber component. The rubber composition of the present invention may contain, in addition to the polymer composition of the present invention, inorganic fillers such as carbon black and silica; softeners; antioxidants; vulcanization accelerators such as sulfenamide-based vulcanization accelerators and thiram-based vulcanization accelerators; stearic acid; zinc oxide; vulcanizing agents, etc.

[0039] <Tires> The tire of the present invention is made using the rubber composition of the present invention. Depending on the type and materials of the tire to be applied, the tire may be obtained by molding an unvulcanized rubber composition and then vulcanizing it, or by obtaining semi-vulcanized rubber from an unvulcanized rubber composition through a pre-vulcanization process, etc., molding with this semi-vulcanized rubber, and then further vulcanizing it. In addition to ordinary air or air with adjusted oxygen partial pressure, inert gases such as nitrogen, argon, and helium can be used as the gas to fill the tire. The tire of the present invention can be used as a tire for various purposes, such as for passenger cars, light trucks, and aircraft.

[0040] The polymer compositions, rubber compositions, and various components (resins, rubber, various additives, etc.) contained in tires described herein may be partially or entirely derived from fossil resources, from biological resources such as plant resources, or from recycled resources such as used tires. Furthermore, these various components may be derived from a mixture of two or more of the fossil resources, biological resources, and recycled resources. [Examples]

[0041] The present invention will be described in more detail below with reference to examples, but these examples are for illustrative purposes only and do not limit the present invention in any way.

[0042] <Examples 1-4 and Comparative Examples 1-5> (Diene polymer) 1) Modified SBR: Modified styrene-butadiene copolymer rubber synthesized by synthesis method 1 2) Unmodified SBR: Unmodified styrene-butadiene copolymer rubber synthesized by synthesis method 2

[0043] (resin) Oil: Manufactured by JX Nippon Oil & Energy Corporation, product name "JOMO PROCESS NC300BN" C5C9 resin: Manufactured by Zeon Corporation, product name "Quintone G100B" C5 series resin: Manufactured by Zeon Corporation, product name "Quintone A100" Alpha-methylstyrene resin: Manufactured by Cray Valley, product name "Cleartack W 140" Styrene-based monomer monopolymer resin: Manufactured by Mitsui Chemicals, Inc., product name "FTR8120"

[0044] (Synthesis method 1) In a glass bottle under an inert atmosphere, cyclohexane (200 g), butadiene / cyclohexane solution (25% by mass, 216 g), and styrene (6 g) were added and mixed. Then, 2,2-di-(2-tetrahydrofuryl)propane / cyclohexane solution (0.2 M, 0.18 mL) and n-butyllithium solution (1.6 M, 0.19 mL) were added. The mixture was gently shaken at 50°C for 4 hours, after which 0.3 mol of N,N-bis(trimethylsilyl)-(3-amino-1-propyl)](methyl)(diethoxy)silane was added. The mixture was then allowed to permeate for a further 30 minutes at 50°C. Subsequently, an appropriate amount of degassed isopropyl alcohol was added to the glass bottle to completely terminate the reaction, and then 0.6 mL of isopropyl alcohol solution (5% by mass) of 2,6-di-t-butyl-p-cresol was added to the resulting polymer cement. Take out a portion of the polymer cement, 1 When the molecular properties of the polymer (modified SBR) were investigated using the integration ratio of 1H-NMR, it was found that the amount of styrene (St) bound in the polymer was 11%, and the amount of vinyl (Vi) bound in the butadiene portion was 47 mol%. The number-average molecular weight of the polymer (modified SBR) was measured using gel permeation chromatography and found to be 612,000 (612k) g / mol in terms of monodisperse polystyrene.

[0045] (Synthesis method 2) In a glass bottle under an inert atmosphere, cyclohexane (300 g), butadiene / cyclohexane solution (25% by mass, 108 g), and styrene (3 g) were added and mixed. Then, a cyclohexane solution containing 2,2-di-(2-tetrahydrofuryl)propane / cyclohexane solution (0.2 M, 0.10 mL) and 1,3-bis(1-lithio-1,3-dimethylpentyl)benzene (0.15 M, 0.76 mL) was added. The mixture was gently shaken at 50°C for 10 hours, and then polymerization was terminated by adding an appropriate amount of degassed isopropyl alcohol to the glass bottle. To the obtained polymer cement, 0.3 mL of an isopropyl alcohol solution of 2,6-di-t-butyl-p-cresol (5% by mass) was added. Take out a portion of the polymer cement, 1 When the molecular properties of the polymer (unmodified SBR) were investigated using the integration ratio of 1H-NMR, the amount of styrene (St) bound in the polymer was found to be 11%, and the amount of vinyl (Vi) bound in the butadiene portion was 45 mol%. The number-average molecular weight of the polymer (unmodified SBR) was measured using gel permeation chromatography and found to be 1,140,000 (1140k) g / mol in terms of monodisperse polystyrene.

[0046] [Preparation of polymer compositions] The polymer cement obtained by synthesis methods 1 and 2 (containing 30 g of polymer) was mixed with a THF solution containing 15 g of various resins, and the mixture was shaken for 30 minutes. The resulting polymer cement was reprecipitated with isopropyl alcohol and dried under reduced pressure to obtain the polymer composition. In Tables 1 and 2, the unit of composition for each component is [parts by mass]. For example, in Table 1, Example 2 means that it was prepared by mixing 100 parts by mass of modified SBR having a bound styrene content (St) of 11%, a vinyl bond content (Vi) of the butadiene portion of 47 mol%, a number average molecular weight (Mn) of 612,000 (612k) g / mol, and a glass transition temperature (Tg) of -54°C; and 50 parts by mass of a styrene-based monomer monopolymer resin having a number average molecular weight (Mn) of 886 g / mol, a weight average molecular weight (Mw) of 1605 g / mol, a molecular weight distribution (MWD) of 1.81, a %H Ar content of 31.60%, a glass transition temperature (Tg) of 70°C, and a softening point (Ts) of 120°C.

[0047] [Mn, Mw, MWD, %H, Ar, Tg, Ts of resins] The number-average molecular weight (Mn), weight-average molecular weight (Mw), molecular weight distribution (MWD), %H Ar, glass transition temperature (Tg), and softening point (Ts) of the resins shown in Table 1 were measured by the following methods.

[0048] (number average molecular weight, weight average molecular weight, molecular weight distribution) A sample was prepared by dissolving approximately 2.5 mg of the resin component in 10 mL of tetrahydrofuran. Using the obtained sample, the average molecular weight of the hydrogenated resin was measured by gel permeation chromatography (GPC) under the following conditions, and the number-average molecular weight (Mn) and weight-average molecular weight (Mw) in polystyrene equivalent were calculated. The MWD was also calculated using Mw / Mn. Column temperature: 40°C ·Injection volume: 50μL • Carrier and flow rate: Tetrahydrofuran 0.6 mL / min

[0049] (%H Ar) 20 mg ± 1 mg of resin was dissolved in 0.7 mL of CDCl3 with 100% deuterated resin, and NMR was performed using a Bruker 500 MHz NMR spectrometer at 25°C with 32 scans. 1 1H NMR was measured. The signal of the internal standard [Si(CH3)3]O was set to 0 ppm, and the %H Ar value was calculated as [(integral value from 8.5 to 6.2 ppm) / (integral value from 8.5 to 0 ppm)] × 100.

[0050] (Glass transition temperature) The glass transition temperature of the resin was measured by a differential scanning calorimeter (DSC). Specifically, in accordance with ISO 22768:2006, using a differential scanning calorimeter "DSC2500" manufactured by TA Instruments, while flowing helium at 50 mL / min, the DSC curve was recorded while heating from -100 °C at a rate of 10 °C / min, and the peak top (Inflection point) of the DSC differential curve was taken as the glass transition temperature.

[0051] (Softening point) The softening point of the resin was measured in accordance with JIS-K2207-1996 (ring method).

[0052] [Evaluation of cold flow resistance of polymer composition] Normally, the cold flow resistance is evaluated using T80, which is the relaxation value of 80% of the torque (ML 1+4 ) when the rotor is rotated and a torque is applied to the polymer composition for 4 minutes starting 1 minute after the residual heat. However, when the relaxation is slow and no difference in T-eight-zero is visible even when the upper limit of the measurement time (4 minutes = 240 seconds) is reached, evaluation was also performed based on the attenuation rate (attenuation rate @ 120 sec) 120 seconds after the rotation stops. In this way, the cold flow resistance was evaluated comprehensively.

[0053] 1. Evaluation of cold flow resistance from the perspective of T80 In accordance with JIS K-6300-1:2001, at a test temperature of 80 °C, with a rotor having an L-shaped configuration and a residual heat time of 1 minute and a rotor rotation time of 4 minutes, the polymer composition was heated to measure ML 1+4 . The measuring device used was a Mooney viscometer "SMV-300RT" manufactured by Shimadzu Corporation. ML 1+4 Immediately after measuring ML 1+4 , the rotation of the L-shaped rotor was stopped, and the time (seconds) required for the ML

[0054] values to decrease by 80% was defined as T80. In Table 1, the T80 values ​​of the Examples and Comparative Examples are indexed with the T80 of Comparative Example 1 set to 100. Similarly, in Table 2, the T80 values ​​of the Examples and Comparative Examples are indexed with the T80 of Comparative Example 3 set to 100. A higher T80 index indicates that the polymer composition has superior cold flow resistance from a T80 perspective.

[0055] 2. Evaluation of cold flow resistance from the perspective of attenuation rate @ 120 sec Using the Shimadzu Corporation Mooney Viscometer "SMV-300RT", under the following conditions, ML 1+4 We measured it. Rotor size: L-type Test temperature: 80℃ Preheating time: 1 minute Test time: 4 minutes Aftertime: 4 minutes Attenuation rate @120sec[%] is ML 1+4 Immediately after measurement, the rotation of the L-shaped rotor was stopped, and the ML at the time of rotation stoppage was measured. 1+4 The value and ML 120 seconds after rotation stopped. 1+4 The values ​​were used and calculated using the following formula. Attenuation rate @ 120 sec [%] =100 × [(ML when rotation stops 1+4 Value) - (ML after 120 seconds) 1+4 Value) / ML at rotation stop 1+4 value

[0056] In Table 1, the attenuation rate at 120 sec for Comparative Example 1 is set to 100, and the attenuation rates at 120 sec for the Examples and Comparative Examples are indexed accordingly. Similarly, in Table 2, the attenuation rate at 120 sec for Comparative Example 3 is set to 100, and the attenuation rates at 120 sec for the Examples and Comparative Examples are indexed accordingly. A larger index for the attenuation rate at 120 sec indicates that the polymer composition has superior cold flow resistance in terms of attenuation rate at 120 sec.

[0057] [Table 1]

[0058] [Table 2]

[0059] The results of the examples and comparative examples shown in Tables 1 and 2 demonstrate that using the polymer composition according to the present invention exhibits excellent cold flow resistance in terms of both T80 and decay rate at 120 sec. On the other hand, many of the polymer compositions of the comparative examples in the present invention that do not contain resin had insufficient cold flow resistance from the viewpoint of T80 (Comparative Examples 1-3, 5). The polymer composition of Comparative Example 4 had excellent cold flow resistance from the viewpoint of T80, but its cold flow resistance from the viewpoint of decay rate @120 sec was insufficient. [Industrial applicability]

[0060] The polymer composition in the present invention can be suitably used as a component of a rubber composition, and this rubber composition can be suitably used in tires for passenger cars, trucks, etc., as well as in various vulcanized rubber articles such as hoses and belts.

Claims

1. A diene polymer having a number-average molecular weight of 500,000 g / mol or more, A resin having a %H Ar value of 20% or more, representing the amount of hydrogen atoms bonded to the aromatic ring [%], and a softening point of 110°C or higher. It contains the resin, and the content of the resin is 20 parts by mass or more per 100 parts by mass of the diene polymer. A polymer composition in which the diene polymer is modified and has at least alkoxysilane groups in its molecular chain.

2. The polymer composition according to claim 1, wherein the diene polymer comprises styrene-butadiene copolymer rubber.

3. The polymer composition according to claim 1 or 2, wherein the glass transition temperature of the diene polymer is -30°C or lower.

4. The aforementioned resin is C ９ The polymer composition according to claim 1 or 2, comprising one or more selected from the group consisting of resin-based resins and terpene-aromatic compound-based resins.

5. The polymer composition according to claim 4, wherein the resin comprises one or more selected from the group consisting of styrene monomer monopolymer resins and terpene-phenol resins.

6. The polymer composition according to claim 1 or 2, wherein the glass transition temperature of the resin is 65°C or higher.

7. The polymer composition according to claim 1 or 2, wherein the number average molecular weight of the resin is 300 g / mol or more.

8. The polymer composition according to claim 3, wherein the glass transition temperature of the diene polymer is -60°C or lower.

9. The polymer composition according to claim 1 or 2, wherein the oil content is 0% by mass.

10. A diene polymer having a number-average molecular weight of 500,000 g / mol or more, A resin having a %H Ar value of 20% or more, representing the amount of hydrogen atoms bonded to the aromatic ring [%], and a softening point of 110°C or higher. The following are mixed, and the amount of the resin is 20 parts by mass or more per 100 parts by mass of the diene polymer. A method for producing a polymer composition in which the diene polymer is modified and has at least one alkoxysilane group in its molecular chain.

11. A rubber composition comprising the polymer composition according to claim 1 or 2.

12. A tire using the rubber composition described in claim 11.

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