WO2014112654A1

WO2014112654A1 - Rubber composition

Info

Publication number: WO2014112654A1
Application number: PCT/JP2014/051314
Authority: WO
Inventors: 山口　毅; 務高嶋; 辰夫山口; 正哲金; 達也千羽
Original assignee: Ｊｘ日鉱日石エネルギー株式会社
Priority date: 2013-01-17
Filing date: 2014-01-16
Publication date: 2014-07-24
Also published as: JP2014136759A

Abstract

Provided is a rubber composition having excellent grip resistance, which contains a styrene-butadiene copolymer as a rubber component, said rubber composition comprising: 100 parts by weight of a styrene-butadiene copolymer in which the content of a cis-1,4-bond in the microstructure of a butadiene unit is 40 wt% or more; and 0.5 to 70 parts by weight of an isobutyrene polymer which comprises 100 to 90 wt% of a structural unit represented by formula (1) and 0 to 10 wt% of an isoprene binding unit represented by formula (2).

Description

Rubber composition

The present invention relates to a rubber composition having excellent grip properties when applied to a tire, and a rubber having excellent grip properties when applied to a tire formed by crosslinking the rubber composition.

Crosslinked products of diene rubbers such as styrene butadiene copolymer rubber (SBR) have excellent grip characteristics and are used, for example, in the tread portion of a tire in contact with the road surface, but due to olefin bonds in the main chain. , Heat resistance, weather resistance, ozone degradation resistance, etc. may be a problem. On the other hand, α-olefin-nonconjugated diene copolymer rubbers such as butyl rubber (IIR) containing a small amount of olefin bond in the main chain and EPDM containing olefin bond only in the side chain have good heat resistance and weather resistance. is there.
Therefore, butyl rubber (IIR) containing a small amount of olefinic bonds in the main chain and α-olefin-nonconjugated diene copolymer containing olefinic bonds only in the side chain, in order to improve the properties of the diene rubber while maintaining the grip characteristics. The rubber composition of the rubber and its cross-linked rubber have been studied, and proposals have been made mainly for SBR / IIR and SBR / EPDM systems. The rubber having a main chain structure typified by butyl rubber is grasped by the change in tan δ. The improvement effect of grip performance (also referred to as tread characteristics) of diene rubber has been recognized. However, in recent years, when the molecular structure of diene rubber is precisely controlled and rubbers with various chemical structures are provided, the individual additivity of each rubber may not be easily established in blend rubber properties. It has been confirmed. This is considered to be due to the morphology before crosslinking that appears based on the compatibility between the two rubbers and the difference in the crosslinking speed between the two rubbers.
The patent documents shown below include modification of halogenated rubber to diene rubber (Patent Document 1), modification of butyl rubber to diene rubber by addition of pentaerythritol and the like (Patent Document 2), modification of diene rubber. Effective as a material, rubber having an olefin structure only in the side chain (Patent Document 3), modification of butyl rubber to diene rubber by addition of minerals mainly composed of sepiolite (Patent Document 4), specified as EPDM, etc. Modification of butyl rubber with respect to diene rubber by use of phosphorous vulcanization accelerator (Patent Document 5), modification of modified butyl rubber with respect to diene rubber by addition of specific chemical substances (Patent Document 6), etc. . However, there has been no report on improvement of tire grip properties by adding an isobutylene polymer or butyl rubber to a diene rubber such as SBR.

Japanese Patent Laid-Open No. 5-1177 JP-A-6-116443 International Patent Publication No. 2011/021437 JP-A-11-246707 JP 11-227409 A JP 2012-167240 A

In order to further improve the grip performance of the diene rubber, the present inventors selected SBR as the diene rubber and a rubber having an isobutylene main chain structure typified by butyl rubber as the modifier, and the molecular structure between them, By specifying the molecular weight relationship, it was found that a rubber having a particularly high grip performance was obtained, and the present invention was completed.

In the first aspect of the present invention, 100 parts by weight of a styrene-butadiene copolymer in which the rubber component is a styrene-butadiene copolymer and the cis-1,4 bond unit in the microstructure of the butadiene unit is 40% by weight or more. On the other hand, the unit represented by the following formula (1) contains 100 to 90% by weight, and the unit represented by the following formula (2) contains 0 to 10% by weight (both are 100% by weight). The present invention relates to a rubber composition containing 0.5 to 70 parts by weight of a polymer.

The second of the present invention is characterized in that the isobutylene polymer has a weight average molecular weight (Mw) of 5,000 to 100,000 and a molecular weight distribution dispersity (Mw / Mn) of 3.0 or less. The present invention relates to a first rubber composition of the present invention.
A third aspect of the present invention relates to the first or second rubber composition of the present invention, wherein the styrene-butadiene copolymer rubber has a butadiene content of 70% by weight or more.
A fourth aspect of the present invention relates to the rubber composition according to any one of the first to third aspects of the present invention, wherein the Mooney viscosity (ML _{1 + 4} , 100 ° C.) is 30 to 50.
A fifth aspect of the present invention relates to a rubber obtained by crosslinking the rubber composition according to any one of the first to fourth aspects of the present invention.
A sixth aspect of the present invention relates to a tire characterized by comprising the fifth rubber of the present invention as a constituent material.

According to the present invention, it is possible to obtain a rubber composition having excellent grip properties when applied to a tire using SBR having high reliability as a tire material as a main raw material.

In the present invention, a solution-polymerized styrene-butadiene copolymer having a cis-1,4-bond unit content of the butadiene unit of the diene polymer of 40% by weight or more is used. These copolymers are described as S-SBR and are commercially available. For example, “Toughden” manufactured by Asahi Kasei Chemicals Corporation can be raised. In principle, the microstructure of butadiene includes a cis-1,4 bond, a trans-1,4 bond, and a 1,2-bond. In the present invention, the cis of the butadiene unit is analyzed by the following analysis method. -1 and 4 units whose content is analyzed to be 40% by weight or more are used. The content of cis-1,4 bonds in ordinary styrene butadiene is less than 35% by weight according to this analysis method.
In the present invention, the ratio of cis-1,4 bonds in the styrene-butadiene copolymer is carried out in accordance with JIS K6239 “How to Determine the Microstructure of Raw Rubber-Solution Polymerized SBR (Quantitative)”. The extracted SBR sample is subjected to ¹ H-NMR measurement and IR measurement to contain cis-1,4 bond unit, trans-1,4 bond unit, 1,2 unit bond and styrene of butadiene unit in SBR. The rate was calculated. These analysis results were shown in the Example mentioned later.
As the content of the cis-1,4 bond structure increases, an increase in the crosslinking rate and an improvement in the properties of high grip properties are expected, but on the other hand, the compatibility with other rubber components also changes. A rubber having an isobutylene main chain structure represented by butyl rubber which has excellent compatibility or so-called microphase separation in response to this change has not been known.
In the present invention, as a modifier of S-SBR, the main chain structure is represented by the following formula (1) and, if necessary, the following formula (2), and the unit of the formula (1) is 100 to 90 An isobutylene polymer having a weight percentage of 0 to 10 wt% of the unit of the formula (2) (both are 100 wt% in total) is used.

The present inventors consider that these isobutylene polymers are excellent in compatibility with S-SBR and constitute so-called microphase separation, judging from the results of Examples described later. That is, by configuring this microphase separation, the total interfacial area with the isobutylene polymer finely dispersed in S-SBR increases, and in the blend system, the formulas (1) and (2), It is considered that the viscoelastic characteristics of the structure mainly represented by the formula (1) are efficiently transmitted to the S-SBR, and the grip performance when applied to a tire is improved.
In order to express the above effect, first, it is preferable to use S-SBR as a continuous phase (or matrix) and an isobutylene-based polymer as a dispersed phase (or domain). The isobutylene polymer is used in an amount of 0.5 to 70 parts by weight with respect to 100 parts by weight of S-SBR. If the amount is 0.5 parts by weight or less, the effect of modifying the isobutylene polymer cannot be sufficiently obtained. If the amount exceeds 70 parts by weight, the phase structure tends to become unstable.
The improvement in grip performance according to the present invention mainly depends on the structure represented by the formula (1) in the isobutylene-based polymer, and therefore the ratio of the structural unit represented by the formula (2) is isobutylene. The content is preferably 10% by weight or less based on the total weight of the polymer.
Moreover, in order to use S-SBR as a continuous phase and an isobutylene polymer as a dispersed phase, in addition to the adjustment of the blending ratio described above, the weight average molecular weight (Mw) of the isobutylene polymer is reduced, and the molecular weight distribution It is also preferable to reduce the dispersity (Mw / Mn). Specifically, it is preferable that the weight average molecular weight (Mw) is 5,000 to 100,000 and the dispersity (Mw / Mn) is 3.0 or less.
Also, in order to use S-SBR as a continuous phase and an isobutylene polymer as a dispersed phase, butadiene having a cis-1,4 bond structure in S-SBR, which is considered highly compatible with the isobutylene polymer. It is preferable to increase the unit weight as much as possible, and the butadiene content in S-SBR is preferably 70% by weight or more.
Among the isobutylene polymers according to the present invention, those having substantially only the structural unit represented by the formula (1) can be obtained from the market. An example is “Tetrax 3T (trade name)” manufactured by JX Nippon Oil & Energy Corporation.
Moreover, the thing containing 10% or less of structural units represented by Formula (2) among the isobutylene-type polymers which concern on this invention can also be obtained from a market. An example is “BUTYL 268” manufactured by JSR Corporation (the content of the structural unit of the formula (2) is 1.8% by weight).
In the present invention, a diene rubber other than S-SBR may be included as a rubber component. For example, styrene-butadiene copolymer (SBR), natural rubber (NR), butadiene rubber (BR), isoprene rubber (IR), nitrile butadiene having a butadiene unit having a cis-1,4 bond content of less than 35% by weight. Rubber (NBR), chloroloprene rubber (CR) and the like. These may use only 1 type and can also use 2 or more types together.
In the present invention, in addition to the isobutylene polymer according to the present invention, an α-olefin-nonconjugated diene compound copolymer rubber other than the α-olefin-nonconjugated diene compound copolymer rubber may be included. For example, EPDM using 1,6-hexadiene, dicyclopentadiene, ethylidene norbornene, or the like. These may use only 1 type and can also use 2 or more types together.
In the rubber composition according to the present invention, the above-mentioned isobutylene polymer, an additive such as a softener / plasticizer, an antioxidant, an ultraviolet absorber, an anti-aging agent, a reinforcing material such as carbon black, and the like, a normal rubber A chemical used in processing is blended to perform crosslinking.
In the case of performing crosslinking of a diene rubber other than normal peroxide crosslinking, when the isobutylene polymer in the present invention substantially contains only the formula (1) as a repeating unit, it is substantially crosslinked. Absent. Even in the final rubber, it is considered to function as an uncrosslinked dispersed phase.
When the structure represented by the formula (2) is substantially contained by 10% by weight or less, the cross-linking of the isobutylene polymer itself and the co-crosslinking of S-SBR and the isobutylene polymer proceed, and the compatibility between the two. Will be further improved.
Among the crosslinking reactions, preferable ones are sulfur-based crosslinking from the viewpoint of grip characteristics when applied to a tire.
Even in the case of having only the structure represented by the formula (1), peroxide crosslinking is carried out when the cross-linking of the isobutylene polymer itself and the co-crosslinking of both including S-SBR are advanced. Is preferred. In this case, since formula (1) causes molecular chain scission, when it is desired to suppress this, it is preferable to use a highly reactive crosslinking agent such as divinylbenzene or m-phenylenebismaleimide.
The Mooney viscosity of the rubber composition before crosslinking is not limited, but the Mooney viscosity (ML _{1 + 4} , 100 ° C.) is preferably 30-50. Outside these ranges, the torque in kneading becomes excessive and insufficient, and the dispersion structure is not sufficiently secured and the dispersion / diffusion of various additives, etc., is insufficient, and the effects of the present invention may not be sufficiently obtained.
Examples of the reinforcing agent include carbon black and silica.
Carbon black is suitably used as a reinforcing agent from the viewpoints of improving wear resistance, improving rolling resistance characteristics, preventing cracks and cracks caused by ultraviolet rays (preventing ultraviolet degradation), and the like. The type of carbon black is not particularly limited, and conventionally known carbon blacks such as furnace black, acetylene black, thermal black, channel black, and graphite can be used. Further, the physical characteristics such as particle size, pore volume and specific surface area of carbon black are not particularly limited, and various carbon blacks conventionally used in the rubber industry, for example, SAF, ISAF, HAF, FEF, GPF, SRF (all are abbreviations of carbon black classified according to the US ASTM standard D-1765-82a) and the like can be used as appropriate. When carbon black is used, the blending amount is preferably 5 to 80 parts by mass, and more preferably 10 to 60 parts by mass with respect to 100 parts by mass of the rubber component (A). Further, it can be 30 to 80 parts by mass, or 40 to 60 parts by mass. In such a blending amount, the effect as a reinforcing agent can be favorably obtained in the rubber composition and the crosslinked rubber composition according to the present embodiment.
As silica, those conventionally used as rubber reinforcing agents can be used without particular limitation, for example, dry method white carbon, wet method white carbon, synthetic silicate white carbon, colloidal silica, precipitated silica and the like. Can be mentioned. The specific surface area of silica is not particularly limited, but usually a silica having a surface area of 40 to 600 m ² / g, preferably 70 to 300 m ² / g, and a primary particle diameter of 10 to 1000 nm should be used. Can do. These may be used alone or in combination of two or more. The amount of silica used is preferably 0.1 to 150 parts by weight, more preferably 10 to 100 parts by weight, and 30 to 100 parts by weight with respect to 100 parts by weight of the rubber component (A). Is more preferable.
Moreover, you may mix | blend a silane coupling agent with a rubber composition in order to mix | blend a silica. Examples of the silane coupling agent include vinyltrichlorosilane, vinyltriethoxysilane, vinyltris (β-methoxy-ethoxy) silane, β- (3,4-epoxycyclohexyl) -ethyltrimethoxysilane, and 3-chloropropyltrimethoxy. Silane, 3-chloropropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, bis (3- (triethoxysilyl) propyl) tetrasulfide, bis (3- (triethoxysilyl) propyl ) Disulfide and the like. These may be used alone or in combination of two or more. The addition amount of the silane coupling agent can be appropriately changed depending on the desired blending amount of silica, but is preferably 0.1 to 20 parts by mass with respect to 100 parts by mass of the rubber component (A).
As the filler, mineral powders such as clay and talc, carbonates such as magnesium carbonate and calcium carbonate, alumina hydrate such as aluminum hydroxide, and the like can be used.
As softeners and plasticizers, plant oil softeners such as tall oil, mainly linoleic acid, oleic acid, and abithienic acid, pineapple, rapeseed oil, cottonseed oil, peanut oil, castor oil, palm oil, fuacitis, paraffinic oil, Examples thereof include naphthenic oils, aromatic oils, and phthalic acid derivatives such as dibutyl phthalate. The blending amount of the softening agent is preferably 0 to 50 parts by mass with respect to 100 parts by mass of the rubber component (A).
The rubber composition according to this embodiment also includes various additives used in the field of the rubber industry, such as anti-aging agents, sulfur, crosslinking agents, vulcanization accelerators, vulcanization retarders, peptizers, processes. You may contain 1 type, or 2 or more types, such as oil and a plasticizer, as needed. The compounding amount of these additives is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the rubber component (A).
Antiaging agents include primary amines such as p, p′-diaminodiphenylmethane; secondary amines such as phenyl-α-naphthylamine and N, N′-diphenyl-p-phenylenediamine; 2,6-di Examples include alkylphenols such as tert-butyl-p-cresol, 2,5-ditert-butyl-hydroquinone and hydroquinone monobenzyl ether; and imidazoles such as 2-mercaptobenzimidazole. The blending amount is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the rubber component (A).
Examples of the vulcanization accelerator include thiuram accelerators such as tetramethylthiuram monosulfide, tetramethylthiuram disulfide, and tetraethylthiuram disulfide; thiazole accelerators such as 2-mercaptobenzothiazole and dibenzothiazyl disulfide; N-cyclohexyl Sulfenamide accelerators such as 2-benzothiazylsulfenamide and N-oxydiethylene-2-benzothiazolylsulfenamide; guanidine accelerators such as diphenylguanidine and diortolylguanidine; n-butyraldehyde -Aldehyde-amine accelerators such as aniline condensates and butyraldehyde-monobutylamine condensates; aldehyde-ammonia accelerators such as hexamethylenetetramine; thiourea accelerators such as thiocarbanilide Agents, and the like. When blending these vulcanization accelerators, one type may be used alone, or two or more types may be used in combination. The content of the vulcanization accelerator is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the rubber component (A).
Vulcanization aids include metal oxides such as zinc oxide (zinc white) and magnesium oxide; metal hydroxides such as calcium hydroxide; metal carbonates such as zinc carbonate and basic zinc carbonate; stearic acid and oleic acid Aliphatic acid salts such as zinc stearate and magnesium stearate; amines such as di-n-butylamine and dicyclohexylamine; ethylene dimethacrylate, diallyl phthalate, N, Nm-phenylenebismaleimide, triallyl isocyanurate And trimethylolpropane trimethacrylate. When blending these vulcanization aids, one type may be used alone, or two or more types may be used in combination. The content of the vulcanization aid is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the rubber component (A).
The rubber composition according to the present embodiment can be produced by applying a method generally used as a method for producing a rubber composition. For example, it can manufacture by mixing each component mentioned above using kneading machines, such as a Brabender, a Banbury mixer, and a roll mixer.

The present invention will be described more specifically with reference to the following examples and comparative examples. However, the present invention is not limited to the following examples.
[Example 1]
As styrene-butadiene copolymer rubber (hereinafter abbreviated as SBR), solution-polymerized styrene-butadiene rubber, trade name “Tuffden 1000” (manufactured by Asahi Kasei Chemicals Co., Ltd.), and polyisobutylene polymer as polyisobutylene, trade name “Tetrax 3T” (manufactured by JX Nippon Oil & Energy Corporation, Mw 32,000, Mw / Mn 2.0) was used.
A filler, a plasticizer, a vulcanizing agent, a vulcanization accelerator, a vulcanization aid, and an anti-aging agent are blended in the amounts shown in Table 1 in 100 parts by weight of the above SBR and 10 parts by weight of polyisobutylene, respectively. 6 inch φ × 16 inch) and kneading under the conditions of a rotation speed of 30 rpm and a front-rear roll rotation ratio of 1: 1.22 to obtain a rubber composition having a predetermined Mooney viscosity.
Silica AQ (manufactured by Tosoh Silica) is used as the filler, process oil “NS-100” (manufactured by Idemitsu Kosan Co., Ltd.) as the plasticizer, and sulfur (Kawagoe Chemical Co., Ltd.) as the vulcanizing agent. Made of Zinc Oxide No. 3 (Hakusui Tech Co., Ltd.) and stearic acid (made by Nippon Seika Co., Ltd.) as vulcanization aids, and sulfenamide accelerators as vulcanization accelerators. “Noxeller CZ (N-cyclohexyl-2-benzothiazylsulfenamide)” (manufactured by Ouchi Shinsei Chemical Co., Ltd.) and the guanidine accelerator “Noxeller D (1,3-diphenylguanidine)” (Emerging Ouchi) Chemical Co., Ltd.) was used as an anti-aging agent, and “anti-aging agent 224” (manufactured by Ouchi Shinsei Chemical Co., Ltd.) was used in the amounts shown in Table 1.
The rubber composition after kneading was compression molded under a vulcanization condition of 160 ° C. × 20 minutes to produce a sheet.
Vulcanization characteristics and dynamic viscoelasticity (that is, an index of grip resistance) at the time of producing the sheet were evaluated. These results are shown in Table 3.
[Example 2]
The same procedure as in Example 1 was performed except that 100 parts by weight of solution-polymerized styrene-butadiene rubber, trade name “Tuffden 2000R” (manufactured by Asahi Kasei Chemicals Corporation) was used as SBR.
[Example 3]
As SBR, 70 parts by weight of solution-polymerized styrene-butadiene rubber, trade name “Tuffden 2000R” (manufactured by Asahi Kasei Chemicals Corporation) is used, and butadiene rubber (BR) (trade name “BR1220”, produced by Nippon Zeon Co., Ltd.). ) The same operation as in Example 1 was carried out except that 30 parts by weight was added (see Table 2).
The polyisobutylene used in Example 4 below is prepared as follows.
[Synthesis of polyisobutylene]
Attach a septum cap, a reflux tube connected to a vacuum line, and a temperature tube to a 300 mL 3-neck flask, put a stirrer bar, and repeat degassing-nitrogen replacement in the system twice using a vacuum line (with a Schlenk tube). And under a normal pressure nitrogen atmosphere. Into the flask, 100 mL of a toluene solvent dried and distilled with calcium hydride was injected from a septum cap using a syringe.
Next, the flask was immersed in a low temperature bath at a predetermined temperature, and after confirming that the liquid temperature in the system reached 10 ° C., 30 g of isobutylene was transferred to the reaction system. When it was confirmed that the liquid temperature in the system was stable at 10 ° C., a 0.1 mol / L ethylaluminum dichloride (EADC) / n-hexane solution in a glove box under a nitrogen atmosphere was isobutylene / EADC = 60. It was weighed with a syringe so as to be 1,000 (molar ratio) and injected into the reactor.
Two hours after the injection of the catalyst solution, the low-temperature bath was removed from the flask and allowed to stand at room temperature. The reaction mixture was extracted with a 1N aqueous sodium hydroxide solution (twice), and the resulting oil phase was extracted with pure water. After confirming that the pH of the aqueous phase became neutral, the solvent was distilled off from the oil phase with an evaporator, and the residue was dried with a vacuum dryer at 1 mmHg for 12 hours at 60 ° C. 21 g of polyisobutylene was obtained.
The polyisobutylene (synthetic product) used in Example 5, Comparative Example 5, Comparative Example 6, and Comparative Example 7 was synthesized in the same manner as above except that the catalyst concentration and the reaction temperature were changed.
[Example 4]
As SBR, 100 parts by weight of solution-polymerized styrene-butadiene rubber, trade name “Tuffden 2000R” (manufactured by Asahi Kasei Chemicals Co., Ltd.) was used, and Mw11,000 and Mw / Mn2.6 polyisobutylene (in the above synthesis method) Preparation) was carried out in the same manner as in Example 1, except that 10 parts by weight were used.
[Example 5]
As SBR, 100 parts by weight of solution-polymerized styrene-butadiene rubber, trade name “Toughden 2000R” (manufactured by Asahi Kasei Chemicals Corporation), and polyisobutylene (synthetic product) of Mw 97,000 and Mw / Mn 1.9 as additives are used. It implemented like Example 1 except having used 10 weight part.
[Example 6]
As SBR, 70 parts by weight of solution-polymerized styrene-butadiene rubber, trade name “Tuffden 2000R” (manufactured by Asahi Kasei Chemicals Corporation) and butyl rubber as an additive, trade name “BUTYL 268” (manufactured by JSR Corporation): ( Example 2 was carried out in the same manner as in Example 1 except that 30 parts by weight of the content of 1.8% by weight was used.
[Comparative Example 1]
The same procedure as in Example 1 was performed except that solution-polymerized styrene-butadiene rubber, “SL-552 (manufactured by JSR Corporation)” was used as SBR.
[Comparative Example 2]
The same procedure as in Example 1 was performed except that solution-polymerized styrene-butadiene rubber, “SL-563 (manufactured by JSR Corporation)” was used as SBR.
[Comparative Example 3]
The same procedure as in Example 1 was performed except that solution-polymerized styrene-butadiene rubber, “NS116R (manufactured by Nippon Zeon Co., Ltd.)” was used as SBR.
[Comparative Example 4]
The SBR was carried out in the same manner as in Example 1 except that “Tuffden 2003 (manufactured by Asahi Kasei Chemicals Corporation)” was used as the solution-polymerized styrene-butadiene rubber.
[Comparative Example 5]
As SBR, solution polymerized styrene-butadiene rubber, trade name “Toughden 2000R” (manufactured by Asahi Kasei Chemicals Corporation) was used, and polyisobutylene (synthetic product) of Mw 3,800 and Mw / Mn 2.9 was used as an additive. Except for this, the same procedure as in Example 1 was performed.
[Comparative Example 6]
As SBR, solution polymerized styrene-butadiene rubber, trade name “Toughden 2000R” (manufactured by Asahi Kasei Chemicals Corporation) was used, and polyisobutylene (synthetic product) of Mw 33,000 and Mw / Mn 3.8 was used as an additive. Except for this, the same procedure as in Example 1 was performed.
[Comparative Example 7]
As SBR, solution-polymerized styrene-butadiene rubber, trade name “Tuffden 2000R” (manufactured by Asahi Kasei Chemicals Corporation) was used, and polyisobutylene (synthetic product) of Mw 205,000 and Mw / Mn 2.8 was used as an additive. Except for this, the same procedure as in Example 1 was performed.

[Measurement of Mooney viscosity]
The Mooney viscosity was measured according to JIS K 6300-1: 2001 “Unvulcanized rubber—physical properties—Part 1: Determination of viscosity and scorch time using Mooney viscometer”. Table 3 shows the measurement results.
[Measurement of vulcanization speed]
The measurement of the vulcanization speed was carried out according to JIS K 6300-2: 2001 “Unvulcanized rubber—Physical characteristics—Part 2: Determination of vulcanization characteristics using a vibration vulcanization tester”. Table 3 shows the measurement results, with the time until the vulcanization degree reaches 90% (T90, minutes) as the vulcanization rate.
[Measurement of dynamic viscoelasticity]
The measurement of dynamic viscoelasticity was carried out according to JIS K 7244-4: 1999 “Plastics—Testing method of dynamic mechanical properties—Part 4: Tensile vibration—Non-resonance method”. Specifically, one test piece having a thickness of 1 mm, a width of 5 mm, and a length of 40 mm was cut out from the sheets obtained in Examples 1 and 2 and Comparative Examples 1 to 5, and the frequency was 10 Hz and the dynamic strain was 0. Under the condition of 0.1%, the measurement temperature was measured in the tensile mode while the temperature was raised in the range of −50 to 100 ° C. at 2 ° C./min. The apparatus used is a dynamic viscoelasticity measuring apparatus RSA-3 (manufactured by TA INSTRUMENTS). When the time conversion side of viscoelasticity is used, the wet grip property correlates with a loss coefficient (tan δ) value at 10 Hz-0 ° C., and the wet grip property (brake braking property) is better as the value is larger. It is known. Table 3 shows the measurement results.

Examples 1 to 6 have a large 0 ° C. tan δ value (good grip properties). In addition, the vulcanization speed is fast and the productivity is excellent.
The rubber composition of the present invention can be particularly suitably used for tire applications. For example, automobile tires and tubes, inner liners, bead fillers, plies, belts, tread rubbers, side rubbers, various sealing materials, sealants, and aircraft use It can be used for applications such as tires and tubes, bicycle tires and tubes, solid tires, and corrected tires.
In addition to tire applications, it can be used for applications such as shoe soles, grips for golf and tennis clubs, golf balls, tennis balls, and the like.

The rubber composition according to the present invention can achieve both improvement in productivity due to an increase in the crosslinking speed and improvement in gripping properties, and can be particularly suitably used for tire tread applications. There is a possibility that it can be used for applications such as grips for clubs such as tennis, golf balls, tennis balls and the like.

Claims

The rubber component is a styrene-butadiene copolymer, and 100 parts by weight of the styrene-butadiene copolymer in which the cis-1,4 bond of the microstructure of the butadiene unit is 40% by weight or more,
An isobutylene polymer containing 100 to 90% by weight of a unit represented by the following formula (1) and 0 to 10% by weight of a unit represented by the following formula (2) (both are 100% by weight). A rubber composition containing 0.5 to 70 parts by weight.
The isobutylene polymer has a weight average molecular weight (Mw) of 5,000 to 100,000 and a molecular weight distribution dispersity (Mw / Mn) of 3.0 or less. Rubber composition.
The rubber composition according to claim 1, wherein the styrene content of the styrene-butadiene copolymer rubber is 70% by weight or more.
The rubber composition according to any one of claims 1 to 3, wherein Mooney viscosity (ML 1 + 4 , 100 ° C) is 30 to 50.
A rubber obtained by crosslinking the rubber composition according to any one of claims 1 to 4.
A tire comprising the rubber according to claim 5 as a constituent material.