Polymer composition and method for producing same, rubber composition and tire

Abstract

The present invention addresses the problems of: providing a polymer composition having excellent cold flow resistance; a method for producing the polymer composition; a rubber composition containing the polymer composition; and a tire obtained using the rubber composition. The polymer composition 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 DEG C or more, and the content of the resin is 20 parts by mass or more per 100 parts by mass of the diene polymer.

Description

Technical Field

[0001] The present disclosure relates to polymer compositions and methods for making the same, rubber compositions, and tires. Background Art

[0002] Polymers used in tire manufacturing can be relatively high molecular weight to meet various performance requirements. In this case, oil-added polymers with added processing oils are sometimes used to improve processability. In addition, polymers with added resins are sometimes used to improve both the tire's grip and its processability.

[0003] For example, JP2020-528487A (PTL 1) discloses a technique for reducing the adhesiveness of a composition by using a polymer to which a specific resin is added.

[0004] Citation List

[0005] Patent Literature

[0006] PTL 1: JP2020-528487A Summary of the invention

[0007] Problem that the invention aims to solve

[0008] However, polymers to which oil or resin is added, such as those exemplified in PTL 1, tend to cause a significant cold flow phenomenon, and improvement from this viewpoint has been sought.

[0009] Therefore, an object of the present invention is to provide a polymer composition having excellent cold flow resistance and a method for producing the same, a rubber composition containing the polymer composition, and a tire using the rubber composition.

[0010] Solutions for solving problems

[0011] <1> A polymer composition comprises a diene polymer having a number average molecular weight of 500,000 g / mol or more and a resin having a % HAr value of 20% or more and a softening point of 110° C. or more, wherein the content of the resin is 20 parts by mass or more relative to 100 parts by mass of the diene polymer.

[0012] <2> according to <1> The polymer composition, wherein the diene polymer comprises styrene-butadiene copolymer rubber.

[0013] <3> according to <1> or <2> The polymer composition, wherein the glass transition temperature of the diene polymer is below -30°C.

[0014] <4> according to <1> to <3> The polymer composition described in any one of the preceding claims, wherein the diene polymer is modified.

[0015] <5> according to <1> to <4> The polymer composition described in any one of the preceding claims, wherein the resin comprises at least one selected from the group consisting of C9-based resins and terpene-aromatic compound-based resins.

[0016] <6> according to <5> The polymer composition, wherein the resin comprises at least one selected from homopolymer resins of styrene monomers and terpene-phenol resins.

[0017] <7> according to <1> to <6> The polymer composition described in any one of the preceding claims, wherein the glass transition temperature of the resin is 65° C. or higher.

[0018] <8> according to <1> to <7> The polymer composition described in any one of the preceding claims, wherein the number average molecular weight of the resin is 300 g / mol or more.

[0019] <9> according to <3> The polymer composition, wherein the glass transition temperature of the diene polymer is below -60°C.

[0020] <10> according to <1> to <9> The polymer composition described in any one of the preceding claims, wherein the oil content is 0 mass %.

[0021] <11> A method for producing a polymer composition comprises mixing a diene polymer having a number average molecular weight of 500,000 g / mol or more and a resin having a % HAr value of 20% or more and a softening point of 110° C. or more, wherein the resin is blended in an amount of 20 parts by mass or more per 100 parts by mass of the diene polymer.

[0022] <12> A rubber composition comprising <1> to <10> The polymer composition described above.

[0023] <13> A tire, which uses <12> The rubber composition.

[0024] Effects of the Invention

[0025] The present disclosure can provide a polymer composition having excellent cold flow resistance and a method for producing the same, as well as a rubber composition containing the polymer composition and a tire using the rubber composition. DETAILED DESCRIPTION

[0026] <Polymer composition>

[0027] The polymer composition of the present disclosure comprises a diene polymer having a number average molecular weight of 500,000 g / mol or more and a resin having a % HAr value of 20% or more and a softening point of 110° C. or more, wherein the content of the resin is 20 parts by mass or more relative to 100 parts by mass of the diene polymer.

[0028] Hereinafter, “a diene polymer having a number average molecular weight of 500,000 g / mol or more” may be referred to as “a diene polymer of the present disclosure”; and “a resin having a % HAr value of 20% or more and a softening point of 110° C. or more” may be referred to as “a resin of the present disclosure”.

[0029] Conventionally, a diene polymer having rigidity, such as an oil-extended styrene-butadiene copolymer rubber (oil-extended SBR) having a number average molecular weight of 500,000 g / mol or more, is sometimes mixed with oil or the like as a plasticizer to improve the processability of the polymer. However, when the diene polymer mixed with oil or the like is processed into sheets or blocks and stacked for storage, the diene polymer is easily deformed and flows (cold flow phenomenon).

[0030] In contrast, the polymer composition of the present disclosure has excellent cold flow resistance. The reason for this is not clear, but it is presumed to be due to the following reasons.

[0031] The resin of the present disclosure has a % HAr value of 20% or more and a softening point of 110°C or more, and therefore has low compatibility with a diene polymer having a number average molecular weight of 500,000 g / mol or more, and has rigidity. Therefore, it is believed that the resin of the present disclosure plays a role similar to a filler that is difficult to relax in the diene polymer of the present disclosure. As a result, it is believed that the deformation of the polymer composition can be suppressed, and the cold flow phenomenon can be suppressed.

[0032] The following is a detailed description of the ingredients of the polymer composition.

[0033] [Diene polymer]

[0034] The number average molecular weight of the diene polymer disclosed in the present disclosure is 500,000 g / mol or more.

[0035] Hereinafter, the last three digits of a molecular weight ",000" are represented by "k", and 500,000 may be described as "500k".

[0036] In the present disclosure, the number average molecular weight (Mn) refers to the polystyrene equivalent number average molecular weight measured by gel permeation chromatography (GPC).

[0037] The number average molecular weight of the diene polymer is preferably greater than 500,000 (500k) g / mol, more preferably greater than 1,000,000 (1000k) g / mol, and even more preferably greater than 1,250,000 (1250k) g / mol. 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 even more preferably 2,000,000 (2000k) g / mol or less.

[0038] From the viewpoint of further improving the balance between rolling resistance and WET performance of a tire obtained from a rubber composition including the polymer composition of the present disclosure, the glass transition temperature (Tg) of the diene polymer is preferably -30°C or lower, more preferably -45°C or lower, and even more preferably -60°C or lower. The glass transition temperature (Tg) of the diene polymer is preferably -80°C or higher.

[0039] The Tg of the diene polymer can be measured by differential scanning calorimetry (DSC).

[0040] The diene polymer is preferably modified. In other words, the diene polymer preferably has a modified functional group in the molecular chain.

[0041] By modifying the diene polymer, when the rubber composition containing the polymer composition of the present disclosure contains a filler, the filler dispersibility is improved, and a vulcanized rubber having low heat generation can be obtained.

[0042] The diene polymer can be modified with a modifier such as an alkoxysilane compound, an amine compound or a tin compound. Only one modifier can be used, or two or more modifiers can be used. By using these modifiers, the diene polymer can have a modified functional group in the molecular chain, such as an alkoxysilane group; a primary, secondary or tertiary amino group or a group containing a tin atom. In addition, the primary amino group and the secondary amino group can be protected by a hydrolyzable protective group. The diene polymer can have only one or more modified functional groups. Among them, the diene polymer preferably has at least an alkoxysilane group in the molecular chain, and more preferably has an amino group in addition.

[0043] 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, acrylonitrile-butadiene rubber (NBR). SBR, BR and IR may also be hydrogenated.

[0044] Only one kind of the diene polymer may be used or two or more kinds of the diene polymer may be used.

[0045] Among them, the diene polymer of the present disclosure preferably contains a styrene-butadiene copolymer rubber (SBR), and more preferably consists of a styrene-butadiene copolymer rubber (SBR).

[0046] From the viewpoint of the balance between rolling resistance and WET performance of a tire obtained from a rubber composition comprising the polymer composition of the present disclosure, the vinyl bond content (Vi) in the diene compound portion of the diene polymer is preferably 10 mol % to 70 mol %, more preferably 15 mol % to 60 mol %, even more preferably 20 mol % to 50 mol %.

[0047] The vinyl bond content of the diene polymer can be determined by 1 H-NMR spectroscopy determination.

[0048] When a modified or unmodified SBR is used as the diene polymer, from the viewpoint of low loss and WET performance of a tire obtained from a rubber composition comprising the polymer composition of the present disclosure, the bound styrene content (St) of the modified or unmodified SBR is preferably 3 mol% to 25 mol%, more preferably 4 mol% to 22 mol%, and even more preferably 5 mol% to 18 mol%.

[0049] The bound styrene content of modified or unmodified SBR can be determined by 1 H-NMR spectroscopy determination.

[0050] [Resin]

[0051] The polymer composition contains a resin having a %H Ar value of 20% or more and a softening point of 110° C. or more (resin of the present disclosure), wherein the content of the resin of the present disclosure in the polymer composition is 20 parts by mass or more per 100 parts by mass of the diene polymer.

[0052] If the content of the resin disclosed in the polymer composition is less than 20 parts by mass relative to 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 disclosed 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 relative to 100 parts by mass of the diene polymer.

[0053] The content of the resin of the present disclosure in the polymer composition 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, relative to 100 parts by mass of the diene polymer.

[0054] (% HAr value)

[0055] The % HAr value represents the amount [%] of hydrogen atoms (H) bonded to an aromatic ring (Ar) in a compound and indicates the degree of polarity with respect to the structure of the resin, and can be determined using the following formula when hydrogen atoms in the resin are divided into hydrogen atoms of aromatic and non-aromatic origin.

[0056] %H Ar value = [amount of hydrogen atoms of aromatic origin / (amount of hydrogen atoms of aromatic origin + amount of hydrogen atoms of non-aromatic origin)] × 100

[0057] When the %H Ar value is large, the polarity is large and the compatibility with the diene polymer having a number average molecular weight of 500,000 g / mol or more is small. When the %H Ar value is small, the polarity is low and the compatibility with the diene polymer having a number average molecular weight of 500,000 g / mol or more is high.

[0058] The resin of the present disclosure has a %H Ar value of 20% or more, and thus has low compatibility with a diene polymer having a number average molecular weight of 500,000 g / mol or more.

[0059] The higher the %H Ar value of the resin disclosed herein, the lower and better the compatibility with the diene polymer. This value is preferably 25% or more, more preferably 30% or more. The %H Ar value of the resin disclosed herein is preferably 62.5% or less.

[0060] The %H Ar value can be determined as follows.

[0061] 20 mg ± 1 mg of the resin was dissolved in CDCl3 (0.7 mL) having a deuterated ratio of 100%, and the reaction mixture was measured at 25°C with 32 scans using a 500 MHz NMR manufactured by Bruker. 1 H NMR. When the signal of the internal standard [Si(CH3)3]O was set to 0 ppm, %H Ar was calculated as [(integrated value from 8.5 ppm to 6.2 ppm) / (integrated value from 8.5 ppm to 0 ppm)]×100.

[0062] The solubility parameter (SP) value is sometimes used as a property indicating the compatibility between a polymer and a resin, but when the molecular structure of the resin is unknown, the SP value cannot be calculated. On the other hand, the % HAr value is an indicator of the aromatic component, which is important for the compatibility of a diene polymer with a resin, and can indicate the compatibility even when the molecular structure details are unknown.

[0063] (Softening point)

[0064] The softening point (Ts) of the resin of the present disclosure is 110° C. or higher.

[0065] The softening point of the resin disclosed in the present invention is 110° C. or higher, which can impart rigidity to the polymer composition and suppress its deformation and cold flow phenomenon.

[0066] The softening point of the resin of the present disclosure is preferably 115° C. or higher, more preferably 120° C. or higher. In addition, from the viewpoint of processability of the polymer composition, the softening point of the resin of the present disclosure is preferably 150° C. or lower, more preferably 145° C. or lower, and even more preferably 140° C. or lower.

[0067] The softening point can be measured according to the method of JIS-K2207-1996 (ring and ball method).

[0068] The resin of the present disclosure is not limited as long as the %H Ar value is 20% or more and the softening point is 110° C. or more, and examples thereof include C5-C9 series resin, C9 series resin, terpene-aromatic compound series resin, DCPD-aromatic compound series resin.

[0069] Only one kind of resin may be used, or two or more kinds may be used.

[0070] Among them, from the viewpoint of achieving both %H Ar value and softening point, C9-based resins and terpene-aromatic compound-based resins are preferred, and homopolymer-based resins of styrene-based monomers and terpene-phenol resins are preferred.

[0071] The C9 series resin refers to a solid polymer obtained by polymerizing a C9 fraction using a Friedel-Crafts catalyst such as AlCl3 or BF3.

[0072] Examples of C9-based resins include (co)polymers containing indene, α-methylstyrene, vinyltoluene, etc. as main components. C9-based resins preferably include homopolymer-based resins of styrene monomers, such as polystyrene, α-methylstyrene resin, vinyltoluene resin, and α-methylvinyltoluene resin. Homopolymer-based resins of styrene monomers are preferably polystyrene and α-methylstyrene resin.

[0073] A typical example of a terpene-aromatic compound resin is a terpene-phenol resin. The terpene-phenol resin can be obtained by a method including reacting a terpene compound and various phenols with each other using a Friedel-Crafts catalyst, or further condensing the resultant with formalin. The terpene of the raw material is not limited, but is preferably a monoterpene hydrocarbon such as α-pinene, limonene, etc., more preferably a terpene containing α-pinene, and particularly preferably α-pinene. Styrene and the like may be contained in the skeleton.

[0074] From the viewpoint of suppressing deformation of the polymer composition, the glass transition temperature of the resin of the present disclosure is 65° C. or higher, more preferably 70° C. or higher. In addition, from the viewpoint of cold flow resistance, the glass transition temperature of the resin of the present disclosure is preferably 100° C. or lower, more preferably 97° C. or lower, and even more preferably 93° C. or lower.

[0075] The glass transition temperature of the resin of the present disclosure can be measured by differential scanning calorimetry (DSC).

[0076] The number average molecular weight (Mn) of the resin of the present disclosure is preferably 300 g / mol or more. When the number average molecular weight of the resin of the present disclosure is 300 g / mol or more, the compatibility of the resin of the present disclosure with the diene polymer may be reduced.

[0077] The number average molecular weight (Mn) of the resin disclosed herein refers to a polystyrene equivalent number average molecular weight measured by gel permeation chromatography (GPC).

[0078] The number average molecular weight of the resin disclosed herein is more preferably 500 g / mol or more, even more preferably 600 g / mol or more. The number average molecular weight of the resin disclosed herein is preferably 1000 g / mol or less, more preferably 950 g / mol or less, even more preferably 900 g / mol or less.

[0079] From the viewpoint of compatibility with the diene polymer, the weight average molecular weight (Mw) of the resin of the present disclosure is preferably 1000 to 2000 g / mol, more preferably 1200 to 1900 g / mol, even more preferably 1400 to 1800 g / mol.

[0080] The weight average molecular weight (Mw) refers to the polystyrene equivalent weight average molecular weight measured by gel permeation chromatography (GPC).

[0081] From the viewpoint of compatibility with the diene polymer, the molecular weight distribution (MWD) of the resin of the present disclosure is preferably from 1.30 to 2.50, more preferably from 1.40 to 2.40, and even more preferably from 1.50 to 2.30.

[0082] The molecular weight distribution (MWD) of the resin of the present disclosure can be calculated from the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn).

[0083] As described above, when the polymer composition includes the diene-based polymer of the present disclosure and a given amount of the resin of the present disclosure, the glass transition temperature of the polymer composition may be increased and an incompatible high Tg region may be generated, thereby suppressing the cold flow phenomenon.

[0084] The glass transition temperature of the polymer composition can be measured by differential scanning calorimetry (DSC).

[0085] The polymer composition may further include components other than the diene polymer of the present disclosure and the resin of the present disclosure, but should not contain oil. In other words, the oil content in the polymer composition is preferably 0% by mass. The absence of oil in the polymer composition makes it easier to maintain the rigidity of the polymer composition.

[0086] Here, the oil refers to a softener that is liquid at 25° C., and examples thereof include mineral oils such as process oils, vegetable oils, and the like.

[0087] From the viewpoint of further improving the cold flow resistance of the polymer composition, the polymer composition is preferably composed of the diene polymer disclosed herein and the resin disclosed herein.

[0088] <Method for producing polymer composition>

[0089] The method for producing a polymer composition disclosed herein comprises mixing a diene polymer having a number average molecular weight of 500,000 g / mol or more and a resin having a % HAr value of 20% or more and a softening point of 110° C. or more, wherein the resin is blended in an amount of 20 parts by mass or more relative to 100 parts by mass of the diene polymer.

[0090] As the diene polymer having a number average molecular weight of 500,000 g / mol or more, the polymers described as the diene polymers of the present disclosure can be used, and the preferred aspects are the same. In addition, examples of the resin having a %H Ar value of 20% or more and a softening point of 110° C. or more include the resins described as the resins of the present disclosure, and the preferred aspects are the same.

[0091] From the viewpoint of further improving the cold flow resistance of the manufactured polymer composition, the compounding amount of the resin of the present disclosure 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, relative to 100 parts by mass of the diene polymer; and 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.

[0092] <Rubber composition>

[0093] The rubber composition of the present disclosure includes the polymer composition of the present disclosure.

[0094] The rubber composition of the present disclosure may contain, as a rubber component, a diene rubber such as natural rubber, isoprene rubber, butadiene rubber, etc. When the diene polymer of the present disclosure is a diene polymer, the polymer composition of the present disclosure may be used as a rubber component.

[0095] In addition to the polymer composition of the present disclosure, the rubber composition of the present disclosure may include inorganic fillers such as carbon black and silica; softeners; antioxidants; vulcanization accelerators such as sulfenamide-based vulcanization accelerators and thiuram-based vulcanization accelerators; stearic acid; zinc oxide; a vulcanizing agent, etc.

[0096] <Tires>

[0097] The tire of the present disclosure is formed using the rubber composition of the present disclosure.

[0098] Depending on the type or member of the tire to be applied, the tire can be obtained by vulcanizing after molding the unvulcanized rubber composition, or can be obtained by first preparing a semi-vulcanized rubber from the unvulcanized rubber composition by a pre-vulcanization process, etc., molding using the semi-vulcanized rubber, and then separately performing main vulcanization. As the gas for filling the tire, an inert gas such as nitrogen, argon or helium as well as normal air or air whose oxygen partial pressure has been adjusted can be used.

[0099] The tires of the present disclosure may be used as tires for passenger cars, light trucks, aircraft, and various other applications.

[0100] The various components (resins, rubbers, various additives, etc.) contained in the polymer compositions, rubber compositions, and tires described herein may be partially or completely derived from fossil resources, biological resources such as plant resources, or recycled resources such as scrap tires. They may also be derived from a mixture of two or more of fossil resources, biological resources, and recycled resources.

[0101] Example

[0102] The presently disclosed technology will be described in more detail below through examples, although these examples are intended for illustrative purposes only and are not intended to limit the scope of the present disclosure in any way.

[0103] <Examples 1 to 4 and Comparative Examples 1 to 5>

[0104] (Diene polymer)

[0105] (1) Modified SBR: modified styrene-butadiene copolymer rubber synthesized by synthesis method 1

[0106] (2) Unmodified SBR: Unmodified styrene-butadiene copolymer rubber (resin) synthesized by Synthesis Method 2

[0107] Oil: Trade name "JOMO PROCESSNC300BN" manufactured by JX Nippon Oil & Energy Corporation

[0108] C5C9-based resin: trade name "Quintone G100B" manufactured by Zeon Corporation

[0109] C5-based resin: Trade name "Quintone A100" manufactured by Zeon Corporation

[0110] α-Methylstyrene resin: trade name "Cleartack W 140" manufactured by Cray Valley

[0111] Homopolymer-based resin of styrene-based monomer: trade name “FTR8120” manufactured by Mitsui Chemicals Co., Ltd.

[0112] (Synthesis Method 1)

[0113] Cyclohexane (200 g), butadiene / cyclohexane solution (25% by mass, 216 g) and styrene (6 g) were added to a glass bottle under an inert atmosphere and mixed, and then 2,2-di-(2-tetrahydrofuranyl)propane / cyclohexane solution (0.2 M, 0.18 mL) and n-butyl lithium 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 [N, N-bis(trimethylsilyl)-(3-amino-1-propyl)](methyl)(diethoxy)silane was added. It was then infiltrated at 50° C. for another 30 minutes. The reaction was then completely terminated by adding an appropriate amount of degassed isopropanol to the glass bottle, and 0.6 mL of an isopropanol solution (5% by mass) of 2,6-di-tert-butyl-p-cresol was added to the resulting polymer mortar.

[0114] Take out a portion of the polymer paste from 1 The molecular characteristics of the polymer (modified SBR) were examined by integrating the H-NMR. The bound styrene content (St) of the polymer was 11%, and the vinyl bond content (Vi) of the butadiene part was 47 mol%.

[0115] The number average molecular weight of the polymer (modified SBR) was measured using gel permeation chromatography and found to be 612,000 (612 k) g / mol from the viewpoint of monodisperse polystyrene.

[0116] The glass transition temperature (Tg) of the polymer (modified SBR) was measured by differential scanning calorimetry (DSC) and found to be -54°C.

[0117] (Synthesis Method 2)

[0118] Cyclohexane (300 g), butadiene / cyclohexane solution (25% by mass, 108 g) and styrene (3 g) were added to a glass bottle under an inert atmosphere and mixed, and then 2,2-di-(2-tetrahydrofuranyl) propane / cyclohexane solution (0.2 M, 0.10 mL) and cyclohexane solution containing 1,3-bis(1-lithio-1,3-dimethylpentyl) benzene (0.15 M, 0.76 mL) were added. The mixture was gently shaken at 50° C. for 10 hours, and then an appropriate amount of degassed isopropanol was added to the glass bottle to terminate the polymerization. 0.3 mL of an isopropanol solution (5% by mass) of 2,6-di-tert-butyl-p-cresol was added to the resulting polymer mortar.

[0119] Take out a portion of the polymer paste from 1 The molecular characteristics of the polymer (unmodified SBR) were examined by integration ratio of H-NMR. The bound styrene content (St) of the polymer was 11%, and the vinyl bond content (Vi) of the butadiene part was 45 mol%.

[0120] The number average molecular weight of the polymer (unmodified SBR) was measured by gel permeation chromatography and was found to be 1,140,000 (1140 k) g / mol from the viewpoint of monodisperse polystyrene.

[0121] The glass transition temperature (Tg) of the polymer (unmodified SBR) was measured by differential scanning calorimetry (DSC) and found to be -55°C.

[0122] [Preparation of polymer composition]

[0123] The polymer cement (containing 30 g of polymer) obtained by Synthesis Methods 1 and 2 was mixed with a THF solution containing 15 g of each resin and shaken for 30 minutes. The obtained polymer cement was reprecipitated with isopropanol and dried under reduced pressure to obtain a polymer composition.

[0124] In Tables 1 and 2, the compounding unit of each component is [parts by mass].

[0125] For example, in Table 1, Example 2 refers to a modified SBR having a bound styrene content (St) of 11%, a vinyl bond amount (Vi) of 47 mol% in the butadiene part, a number average molecular weight (Mn) of 612,000 (612k) g / mol, and a glass transition temperature (Tg) of -54°C, and a homopolymer resin of a styrene monomer 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 of 31.60%, a glass transition temperature (Tg) of 70°C, and a softening point (Ts) of 120°C, which is prepared by mixing 100 parts by mass.

[0126] [Mn, Mw, MWD, %H Ar, Tg, Ts of resin]

[0127] The number average molecular weight (Mn), weight average molecular weight (Mw), molecular weight distribution (MWD), %HAr, glass transition temperature (Tg), and softening point (Ts) of each resin listed in Table 1 were measured by the following method.

[0128] (Number average molecular weight, weight average molecular weight, molecular weight distribution)

[0129] The sample was prepared by dissolving about 2.5 mg of the resin component in 10 mL of tetrahydrofuran. The obtained sample was used to measure the average molecular weight of the hydrogenated resin by gel permeation chromatography (GPC) under the following conditions, and the polystyrene equivalent number average molecular weight (Mn) and weight average molecular weight (Mw) were calculated. MWD was calculated by Mw / Mn.

[0130] Column temperature: 40℃

[0131] Injection volume: 50μL

[0132] Carrier and flow rate: Tetrahydrofuran 0.6mL / min

[0133] (%H Ar)

[0134] 20 mg ± 1 mg of the resin was dissolved in CDCl3 (0.7 mL) having a deuterated ratio of 100%, and the reaction mixture was measured at 25°C with 32 scans using a 500 MHz NMR manufactured by Bruker. 1 H NMR. When the signal of the internal standard [Si(CH3)3]O was set to 0 ppm, %H Ar was calculated as [(integrated value from 8.5 ppm to 6.2 ppm) / (integrated value from 8.5 ppm to 0 ppm)]×100.

[0135] (Glass transition temperature)

[0136] The glass transition temperature of the resin was measured by differential scanning calorimetry (DSC).

[0137] Specifically, according to ISO 22768:2006, a differential scanning calorimeter "DSC2500" manufactured by TA Instruments Japan Inc. was used to record a DSC curve while heating from -100°C at 10°C / min under a helium flow of 50 mL / min, and the peak top (inflection point) of the DSC differential curve was taken as the glass transition temperature.

[0138] (Softening point)

[0139] The softening point of the resin is measured in accordance with JIS-K2207-1996 (ring and ball method).

[0140] [Evaluation of Cold Flow Resistance of Polymer Composition]

[0141] Generally, cold flow resistance is evaluated using T80, which is the torque (ML) when a torque is applied to a polymer composition for 4 minutes by rotating a rotor starting from 1 minute after preheating. 1+4 ) is the 80% relaxation value of the rotation. However, when the relaxation is slow and no difference in T80 is observed even when the upper limit of the measurement time (4 minutes = 240 seconds) is reached, the evaluation is also based on the decay rate (decay rate @ 120 seconds) after the rotation is stopped for 120 seconds. In this way, cold flow resistance is evaluated from multiple aspects.

[0142] 1. Evaluation of cold flow resistance from the perspective of T80

[0143] According to JIS K-6300-1:2001, the polymer composition is heated at a test temperature of 80°C using an L-shaped rotor with a preheating time of 1 minute and a rotor rotation time of 4 minutes to determine ML 1+4 The measuring apparatus was a Mooney viscometer "SMV-300RT" manufactured by Shimadzu Corporation.

[0144] In ML 1+4 Stop the L-shaped rotor immediately after measurement and 1+4 The time (in seconds) required for the value to decrease by 80% is defined as T80.

[0145] In Table 1, T80 of Comparative Example 1 is set to 100, and the T80 values ​​of the embodiments and comparative examples are indexed; in Table 2, T80 of Comparative Example 3 is set to 100, and the T80 values ​​of the embodiments and comparative examples are indexed and listed.

[0146] A larger index value of T80 indicates that the cold flow resistance of the polymer composition from the T80 standpoint is better.

[0147] 2. Evaluation of cold flow resistance from the perspective of decay rate @120 seconds

[0148] ML 1+4 The measurement was performed under the following conditions using a Mooney viscometer "SMV-300RT" manufactured by Shimadzu Corporation.

[0149] Rotor size: L type

[0150] Test temperature: 80℃

[0151] Warm-up time: 1 minute

[0152] Test time: 4 minutes

[0153] After time: 4 minutes

[0154] By determining the ML 1+4 Then stop the L-shaped rotor and use the ML value when the rotation stops. 1+4 Value and ML after rotation stops for 120 seconds 1+4 The decay rate @120 seconds [%] was calculated using the following formula.

[0155] Decay rate @ 120 seconds [%]

[0156] =100×[(ML when rotation stops 1+4 value)-(ML after 120 seconds 1+4 value)] / ML when rotation stops 1+4 value

[0157] In Table 1, the attenuation rate @120 seconds of Comparative Example 1 is set to 100, and the attenuation rates @120 seconds of the embodiments and comparative examples are indexed; in Table 2, the attenuation rate @120 seconds of Comparative Example 3 is set to 100, and the attenuation rates @120 seconds of the embodiments and comparative examples are indexed and listed.

[0158] A smaller decay rate@120 seconds index indicates that the polymer composition has better cold flow resistance in terms of decay rate@120 seconds.

[0159] [Table 1]

[0160]

[0161] [Table 2]

[0162]

[0163] The results of the Examples and Comparative Examples listed in Tables 1 and 2 show that the polymer compositions according to the present disclosure exhibit excellent cold flow resistance in both T80 and decay rate @120 seconds.

[0164] On the other hand, most of the comparative polymer compositions that do not contain the resin of the present disclosure have insufficient cold flow resistance in terms of T80 (Comparative Examples 1-3 and 5). The polymer composition of Comparative Example 4 has excellent cold flow resistance in terms of T80, but has insufficient cold flow resistance in terms of decay rate @ 120 seconds.

[0165] Industrial Applicability

[0166] The polymer compositions of the present disclosure may be suitable for use as a component of rubber compositions suitable for use in various vulcanized rubber articles such as hoses and belts and tires for passenger cars and trucks.

Claims

1. A polymer composition comprising a diene polymer having a number average molecular weight of 500,000 g / mol or more and a resin having a %HAr value of 20% or more and a softening point of 110° C. or more, wherein the content of the resin is 20 parts by mass or more relative to 100 parts by mass of the diene polymer. 2 . The polymer composition according to claim 1 , wherein the diene polymer comprises a styrene-butadiene copolymer rubber. 3 . The polymer composition according to claim 1 , wherein the glass transition temperature of the diene polymer is −30° C. or lower.

4. The polymer composition according to claim 1 or 2, wherein the diene polymer is modified. 5 . The polymer composition according to claim 1 , wherein the resin comprises at least one selected from the group consisting of C9-based resins and terpene-aromatic compound-based resins. 6 . The polymer composition according to claim 5 , wherein the resin comprises at least one selected from the group consisting of homopolymer-based resins of styrene-based monomers and terpene-phenol resins.

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

8. The polymer composition according to claim 1 or 2, wherein the number average molecular weight of the resin is 300 g / mol or more. 9 . The polymer composition according to claim 3 , wherein the glass transition temperature of the diene polymer is −60° C. or lower.

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

11. A method for producing a polymer composition, wherein A diene polymer having a number average molecular weight of 500,000 g / mol or more and a resin having a % HAr value of 20% or more and a softening point of 110° C. or more are mixed, wherein The amount of the resin blended is 20 parts by mass or more relative to 100 parts by mass of the diene polymer. 12 . A rubber composition comprising the polymer composition according to claim 1 or 2 .

13. A tire using the rubber composition according to claim 12.

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