CN104487506B

CN104487506B - Rubber composition for tire tread and pneumatic tire

Info

Publication number: CN104487506B
Application number: CN201380038132.7A
Authority: CN
Inventors: 宫崎达也
Original assignee: Sumitomo Rubber Industries Ltd
Current assignee: Sumitomo Rubber Industries Ltd
Priority date: 2012-08-03
Filing date: 2013-06-13
Publication date: 2019-06-07
Anticipated expiration: 2033-06-13
Also published as: JP6018207B2; CN104487506A; DE112013003160B4; WO2014021002A1; JPWO2014021002A1; DE112013003160T5

Abstract

The present invention provides rubber composition for tire tread, and the pneumatic tire (particularly for passenger car and sports utility vehicle) formed by it, the rubber composition have outstanding wearability and good wet grip performance and also provide good fuel economy and elongation at break simultaneously.The present invention relates to a kind of rubber composition for tire tread, are the 50 mass % modified polybutadiene rubber and 25-75 mass % butadiene-styrene rubber below for silica it includes the cis-content of 8-40 mass % on the basis of 100 mass % rubber components；Relative to 100 mass parts rubber components, the N2 adsorption specific surface area that the rubber composition further includes 40-120 mass parts is 160-270m²The silica of/g.

Description

Rubber composition for tire tread and pneumatic tire

Technical field

The present invention relates to a kind of rubber composition for tire tread and the pneumatic tires formed by the rubber composition.

Background technique

The contact force of passenger car and the tire unit area of sports utility vehicle is low, the tread portion contacted with road surface Need to be provided simultaneously with good wearability, wet grip performance and fuel economy, especially good wearability.

As the example of improve wearability method, silica (the micro mist dioxy for using N2 adsorption large specific surface area is introduced SiClx) or N2 adsorption large specific surface area carbon black (micro mist carbon black) technological means to improve wet grip performance, fuel economy And wearability.(see, e.g., patent document 1).

Unfortunately, fine particle silica polymerize tendency with stronger with micro mist carbon black, therefore is difficult to be uniformly dispersed.It closes In this point, the manufacturers of silica attempt by adjusting silica surface-active and distribution of particles come improve its Dispersibility in rubber composition.However, in the preparation process containing polymer-modified rubber composition, for example, these change Property polymer can inhibit the dispersion of silica in the initial stage of kneading in conjunction with silica.Therefore, fine particle silica Or micro mist carbon black is difficult to be uniformly dispersed, and the use of fine particle silica or carbon black is more likely to reduce elongation at break.

The method of improve wearability known to another kind is the crosslinking agent using sulfur-bearing, for example, 1,6- bis- (N, N '-hexichol Base thiocarbamoyl two is thio) hexane, bis- (3- triethoxysilylpropyl) tetrasulfides or poly- 3,6- dioxaoctane Tetrasulfide, and reduce the use of cyclic annular sulphur (S8).Regrettably, these are expensive containing sulfur crosslinking agent and can only improve about 10% wearability.Method known to other is the masterbatch for preparing the polymer containing silica (or carbon black) and partial amount, And the modified group that addition can interact with silica on the end of the chain or main chain of butadiene-styrene rubber improves silica Dispersibility.Similarly, however, these methods can only improve about 10% wearability, it is therefore desirable to further improve wear-resisting Property.

Technology there are also improve wearability known to another kind is that about 10-35 is added in every 100 mass % rubber components Quality % utilizes the characteristic of polybutadiene rubber itself using the cis-rich polybutadiene rubber that Nd catalyst synthesizes.It is sorry Ground, this technological means can significantly reduce passenger vehicle tyre and sports utility vehicle tire tread is (every in these tires Unit area is low with the electric shock pressure on road surface) wet grip performance.Based on this reason, poly- fourth in every 100 mass % rubber components The content of diene rubber is strictly limited to about 35 mass %.

As described above, it would be desirable to a kind of rubber composition for tire tread be provided, having good wearability and wet grabbing Good fuel economy and good elongation at break are capable of providing while ground performance.

Reference listing

Patent document

Patent document 1:JP 2011-132307A

Summary of the invention

Technical problem

The object of the present invention is to solve the above problems, i.e. offer rubber composition for tire tread is outstanding resistance to having It is capable of providing good fuel economy and elongation at break while mill property and wet grip performance, while providing one kind by the rubber Pneumatic tire obtained by glue composition (especially for passenger car and sports utility vehicle).

The technical solution solved the problems, such as

The present invention relates to a kind of rubber composition for tire tread, and on the basis of 100 mass % rubber components, it includes 8-40 The cis-content of quality % is the 50 mass % modified polybutadiene rubber and 25-55 mass % below for silica Butadiene-styrene rubber；And the rubber components relative to 100 mass parts, it further includes, 40-120 mass parts N2 adsorption specific surface Product is 160-270m²The silica of/g.

Modified polybutadiene rubber for silica is preferably selected from the group being made of following compound extremely Few one kind: the compound modified polybutadiene rubber as shown in following formula (1), by low point that in the molecule includes glycidol amino Son quantifies polymer modified polybutadiene rubber, and by include in the molecule glycidol amino low molecular weight compound with The polybutadiene rubber for the mixture modification that the dimer or high-order oligomer of the low molecular weight compound are constituted,

Wherein R¹, R²And R³It is same or different to each other, respectively represents alkyl, alkoxy, siloxy, acetal radical, carboxylic Base, the derivative of sulfydryl or above-mentioned group；R⁴And R⁵It is same or different to each other, respectively represents hydrogen atom or alkyl, R⁴And R⁵ It can be bonded to each other and constitute ring structure and n together with nitrogen-atoms as integer.

The low molecular weight compound comprising glycidol amino is preferably the compound being shown below in the molecule:

Wherein, R¹¹And R¹²Be same or different to each other, it is each to represent C1-10 alkyl, the alkyl optionally include selected from by At least one of the group that ether and tertiary amine groups are constituted；R¹³And R¹⁴It is same or different to each other, it is each to represent hydrogen atom or C1-20 Alkyl, the alkyl are optionally included selected from least one of the group being made of ether and tertiary amine groups；R¹⁵C1-20 alkyl is represented, The alkyl is optionally included selected from least one of the group being made of ether, tertiary amine groups, epoxy group, carbonyl and halogen group, And m is the integer of 1-6.

Butadiene-styrene rubber preferably includes the modified styrene butadiene rubber for silica.

In addition, the silica relative to 100 mass parts, which preferably includes 1-15 mass parts Selected from least one of the group being made of following compound silane coupling agent: such as following formula (I) compound represented:

Wherein, R¹⁰¹To R¹⁰³Respectively there are branch or unbranched C1-12 alkyl, there is branch or unbranched C1-12 alkane Oxygroup, or-O- (R¹¹¹-O)_z-R¹¹², wherein z R¹¹¹Respectively representing has branch or unbranched C1-30 bivalent hydrocarbon radical and z A R¹¹¹It is same or different to each other, R¹¹²Representing has branch perhaps unbranched C1-30 alkyl has branch or unbranched C2- 30 alkenyls, C6-30 aromatic radical or C7-30 aralkyl and z represent the integer of 1-30, R¹⁰¹To R¹⁰³It is mutually the same or It is different；And R¹⁰⁴Representative has branch or unbranched C1-6 alkylene；

Compound comprising the connection unit A as shown in formula (II) and the connection unit B as shown in formula (III):

Wherein, R²⁰¹Represent hydrogen, halogen, having branch, perhaps unbranched C1-30 alkyl has branch or unbranched C2- 30 alkenyls, the alkyl for thering is branch or unbranched C2-30 alkynyl or its end hydrogen to be substituted by hydroxy or carboxy；R²⁰²Generation Table has branch, and perhaps unbranched C1-30 alkylene has branch or unbranched C2-30 alkylene group or has branch or nothing The C2-30 alkynylene of branch, R²⁰¹And R²⁰²Ring structure can be formed together；And

The compound being shown below:

In addition, it is preferable to use the polybutadiene rubber of rare earth catalyst synthesis on the basis of the 100 mass % rubber components Amount is 40 mass % or less.

The rubber composition for tire tread preferably includes the liquid resin that softening point is -20~45 DEG C, which is At least one of liquid coumarone-indene resin and liquid terpene resin.

The rubber composition for tire tread is preferably comprised selected from the terpene resin for being 46~160 DEG C by softening point, softening point For 46~140 DEG C of rosin resin, the fragrance that the C5 Petropols and softening point that softening point is 46~140 DEG C are 46~140 DEG C At least one of the group that resin is constituted resin.

The present invention relates to the pneumatic tires as obtained by above-mentioned rubber composition.

The pneumatic tire is preferably used for passenger car or sports utility vehicle SUV.

Beneficial effects of the present invention

The present invention provides rubber composition for tire tread, and on the basis of 100 mass % rubber components, it includes 8-40 matter The modified polybutadiene rubber for silica of % is measured, cis-content is 50 mass % hereinafter, and 25-75 mass % Butadiene-styrene rubber；Relative to 100 mass parts rubber components, the N2 adsorption specific surface area for further including 40-120 mass parts is 160-270m²The silica of/g.Therefore, because silica is in polybutadiene rubber region and fourth in this kind of rubber composition It is evenly dispersed in benzene rubber areas, when this rubber composition is used for tire tread, pneumatic tire can be made to have outstanding Wearability and good wet grip performance, while good fuel economy and good elongation at break (durability) being provided.

Specific embodiment

Rubber composition for tire tread according to the present invention includes the modified polybutadiene rubber for silica of specific quantity Glue (BR), cis-content are 50 mass % hereinafter, being used for modification low cis BR, the butadiene-styrene rubber (SBR) of silica, with And N2 adsorption specific surface area is 160-270m²The silica (fine particle silica) of/g.Therefore, the rubber composition, Good fuel economy and elongation at break are capable of providing while having good wearability and wet grip performance.

There is stronger polymerization to be inclined to and be generally difficult to be uniformly dispersed for fine particle silica.Specific quantity is used for dioxy Use (be preferred for silica modified) of the modification low cis BR and SBR of SiClx in the rubber composition allows micro mist Silica is uniformly dispersed, and is allowed while being provided good wearability, wet grip performance, fuel economy and extension at break Rate.Therefore, the balance between these characteristics can be improved significantly.

Rubber components in rubber composition of the invention include the modification low cis BR for silica.This use Allow fine particle silica high degree of dispersion, thus particularly improves fuel economy and wet grip performance, cause on performance improvement Balance.In addition, the modification low cis BR for being used for silica includes the vinyl of reactivity in the molecule, thus even It is also easy to form coupling when using the silane coupling agent such as Si266 of hypoergia, therefore the present invention can be effectively realized Effect.

This is used for the modification low cis BR (change that the quilt for silica can interact with silica of silica The polymer modified modification BR with lower cis-content) it is not particularly limited, as long as it is by comprising can be with titanium dioxide The compound modified BR with lower cis-content of the functional group of silicon interaction can (preferred function group includes choosing From at least one of the group being made of nitrogen, oxygen and silicon atom).Its example includes the modified low cis BR of chain end, It is obtained and being modified with the compound containing functional group (modifying agent) at least one chain end in BR；Main chain changes Property low cis BR, there is on main chain the functional group；And the low cis BR that main chain and chain end are modified, on its main chain With all had on its chain end functional group (for example, on its main chain with functional group and have at least one use modifying agent The modified low cis BR of the main chain and chain end of modified chain end).Wherein, the modified low cis BR of chain end is preferred.

The example of the functional group includes: amino, amide, alkoxysilyl, isocyanates, imino group, imidazoles, urine Element, ether, carbonyl contain oxygen carbonyl, sulfide, disulphide, sulfonyl, sulfinyl, thiocarbonyl, ammonium, acid imide, hydrazine Support, azo, diazo, carboxyl, itrile group, pyridyl group, alkoxy, hydroxyl, oxygen-containing group and epoxy group.These functional groups can be replaced Generation.Particularly, which is preferably primary amino group, secondary amino group or tertiary amino (especially glycidol amino), epoxy group, hydroxyl Base and alkoxy (preferably with the alkoxy of 1-6 carbon atom) or alkoxysilyl (preferably have 1-6 carbon former The alkoxysilyl of son) because it is efficient in terms of promoting fuel economy and wet grip performance.

The modified low cis BR of chain end is preferably to have with what following formula (1) compound represented was modified compared with low cis The modified polybutadiene rubber (S- modified low cis BR) of content.

In formula (1), R¹, R²And R³It is same or different to each other, respectively represents alkyl, alkoxy, siloxy, acetal radical, Carboxyl (- COOH), the derivative of sulfydryl (- SH) or above-mentioned group；R⁴And R⁵It is same or different to each other, respectively represents hydrogen atom Or alkyl, R⁴And R⁵It can be combined with each other and constitute ring structure together with nitrogen-atoms；And n is integer.

The example of the modified BR of S- includes those described in JP 2010-111753A and other patent documents.

In formula (1), R¹, R²And R³Respectively suitably (preferably there is 1-8 carbon atom, more preferable 1-4 for alkoxy The alkoxy of carbon atom), this is because it can obtain outstanding fuel economy and resistance to fracture.R⁴And R⁵Respectively suitably For alkyl (preferably with the alkyl of 1-3 carbon atom).Symbol n is preferably the integer of 1-5, more preferably the integer of 2-4, also more Preferably 3.In addition, in R⁴And R⁵It is combined with each other in the case where constituting ring structure together with nitrogen-atoms, which is preferably 4- 8 member rings.It should be noted that alkoxy include cycloalkyloxy (such as: cyclohexyloxy) and fragrant oxygroup (such as: phenoxy group and benzyl Oxygroup).When this preferred compound is by use, effect of the invention can be implemented well.

The specific example of compound representated by formula (1) includes 2- dimethyl aminoethyl trimethoxy silane, 3- diformazan Base TSL 8330,2- dimethyl aminoethyl triethoxysilane, 3- dimethylaminopropyl triethoxy Silane, 2- diethyllaminoethyl trimethoxy silane, 3- lignocaine propyl trimethoxy silicane, three second of 2- diethyllaminoethyl Oxysilane and 3- lignocaine propyl-triethoxysilicane, in these, preferred 3- dimethylaminopropyl trimethoxy Silane, 3- dimethylaminopropyl triethoxysilane and 3- lignocaine propyl trimethoxy silicane, this is because they Above-mentioned performance is allowed preferably to be improved.Above compound may be used singly or two or more in combination.

Polybutadiene rubber can be modified with formula (1) compound represented by known method, such as JP H06- Method those of described in 53768 B, JP H06-57767 B and other patent documents.For example, polybutadiene rubber can be with It is modified by being contacted with the compound.Specifically, a kind of noticeable method is, it is made by anionic polymerisation After polybutadiene rubber, the compound of predetermined content is added in rubber solutions so that compound and polybutadiene rubber Polymerizable end (reactive terminal) reaction.

The modified low cis BR of chain end is also preferably by the molecule including the low molecular weight chemical combination of glycidol amino The modified modified polybutadiene rubber with low cis content of object.For example, the low cis BR that chain end is modified may suitably be The modified modified polybutadiene rubber with low cis content of low molecular weight compound as shown by:

Wherein, R¹¹And R¹²Mutually the same or different, each to represent a C1-10 alkyl, which optionally includes choosing From at least one of the group being made of ether and tertiary amine groups；R¹³And R¹⁴It is mutually the same or different, it is each represent hydrogen atom or Person's C1-20 alkyl, the alkyl are optionally included selected from least one of the group being made of ether and tertiary amine groups；R¹⁵Represent C1- 20 alkyl, the alkyl optionally include in the group being made of ether, tertiary amine groups, epoxy group, carbonyl and halogen group extremely Few one kind；And m is the integer of 1-6.

R¹¹And R¹²The alkylene of each preferably C1-10 (preferably C1-3).R¹³And R¹⁴Each preferably hydrogen is former Son.R¹⁵The naphthenic base or ring that can be shown below for C3-20 (preferably C6-10, more preferably C8) alkyl and preferably Alkylene, more preferably cycloalkenyl group.

M is preferably 2 or 3.The suitable example of above-mentioned compound as shown in formula includes four glycidyl group-meta-xylene two Amine, four glycidol diaminodiphenylmethanes, four glycidyl group-p-phenylenediamine, 2-glycidyl aminomethyl cyclohexane and four The double aminomethyl cyclohexanes of glycidyl -1,3-.

What the above-mentioned low molecular weight compound by the molecule comprising glycidol amino was modified has low cis content Modified polybutadiene rubber is more preferably low molecular weight compound and the low molecule by the molecule including glycidol amino The modified polybutadiene with low cis content for the mixture modification that the dimer or high-order oligomer for measuring compound are constituted Rubber (A- modified low cis BR).The example of A- modified low cis BR includes JP 2009-275178 A and other patents text Described in offering those.

Oligomer is preferably the dimer of the low molecular weight compound to ten polymers.In addition, the low molecular weight compound is Refer to that molecular weight is 1000 organic compounds below and it can be suitably for such as following formula (2) compound represented:

Wherein, R represents bivalent hydrocarbon radical or the bivalent organic group comprising at least one polar group, this polar group choosing From in by oxygen-containing polar group such as ether, epoxy group and ketone group；Sulfur-bearing polar group such as thioether and thioketones base；And it is nitrogenous In the combination that polar group such as tertiary amino and imino group are constituted.Above-mentioned bivalent hydrocarbon radical can be it is saturation or unsaturated, And can be straight chain, have branch or cricoid.The example of the bivalent hydrocarbon radical includes alkylene, alkylene group and sub- benzene Base.Its specific example includes methylene, ethylene, butylene, cyclohexylene, 1,3- bis- (methylene) hexamethylenes, 1,3- bis- (ethylene Base) hexamethylene, adjacent phenylene, metaphenylene, to phenylene, meta-xylene, paraxylene and bis- (phenylene) methane.

The specific example of low molecular weight compound shown in above-mentioned formula (2) includes: the double amino first of four glycidyl group -1,3- Butylcyclohexane, N, N, N ', N '-four glycidyl group-m-xylene diamine, 4,4- methylene-bis- (N, N- diglycidyl benzene Amine), bis- (N, the N- 2-glycidyl amino) hexamethylenes of Isosorbide-5-Nitrae-, N, N, N ', N '-four glycidyl group-p-phenylenediamine, 4,4 '-is bis- (2-glycidyl amino) Benzophenone, 4- (4- glycidyl piperazinyl)-(N, N- diglycidyl) aniline and 2- [2- (N, N- diglycidyl amino) ethyl] -1- glycidyl pyrrolidines.In these, preferably four glycidol -1, The bis- aminomethyl cyclohexanes of 3-.

The suitable example of above-mentioned oligomer component includes trimer shown in dimer shown in following formula (3) and following formula (4):

When the mixture using low molecular weight compound and oligomer is modified, the mixture with 100 mass % is Benchmark, modifying agent (mixture) preferably comprise, the low molecular weight compound of 75-95 mass % and the oligomer of 25-5 mass %.

The ratio of low molecular weight compound and oligomer can be surveyed by gel permeation chromatography (GPC) in modifying agent It is fixed.

Specifically, allowing to select the pillar analyzed from low molecular weight compound to the sample of oligomer component And to analyze them.By the peak value observed in analysis, along the high molecular weight one at the peak for being originated from low molecular weight compound First inflection point on side vertically draw a line calculate the area of the area of lower-molecular-weight component and high molecular weight component it Between ratio.The area ratio corresponds to the ratio between low molecular weight compound and oligomer component.

It should be noted that the peak on the high molecular weight side from oligomer component is integrated, until its molecular weight reaches not More than 10 times of molecular weight of point of low molecular weight compound (being determined relative to polystyrene standard)；Or it is straight under the following conditions Reach 0 point to the peak of component: if its molecular weight reach no more than low molecular weight compound 10 times of molecular weight of point it Before, the peak of component reaches 0.

Modifying agent and the active end by anionic polymerisation (using polymerization initiator such as lithium compound) synthesis Butadiene polymer reaction by making modifying agent react progress with the reactive terminal of polymer.Using in the molecule comprising contracting The low molecular weight compound of the sweet amino of water or the polybutadiene rubber carried out by the compound in the mixture that its oligomer is constituted The modification of glue, which can be used, to be carried out such as formula (1) compound represented (modifying agent) according to for modified method.

The cis-content of modification low cis BR for silica be 50 mass % hereinafter, preferably 45 mass % with Under, more preferably 40 mass % or less.If its cis-content is more than 50 mass %, due to the titanium dioxide being added in polymer The percentage of silicon-modified group reduces, and BR tends to be not easy to react to each other with silica.The lower limit of its cis-content is without spy It does not limit, preferably 10 mass % or more, more preferably 20 mass % or more.If its cis-content is lower than 10 mass %, Elongation at break EB and wearability may reduce.

The contents of ethylene of modification low cis BR for silica is preferably 35 mass % hereinafter, more preferably 30 matter Measure % or less.If its contents of ethylene is more than 35 mass %, fuel economy and elongation at break EB be may be decreased.Its The lower limit of contents of ethylene is not particularly limited, preferably 1 mass % or more, more preferable 10 mass % or more.If its ethylene Base content is lower than 1 mass %, then E* may be decreased.

The weight average molecular weight (Mw) of modification low cis BR for silica is preferably 200,000 or more, more preferably 400,000 or more.If Mw less than 200,000, will be unable to obtain satisfied wearability and elongation at break.Its Mw is preferably 900,000 hereinafter, more preferably 700, and 000 or less.When the weight average molecular weight Mw of BR is greater than 900,000, processability can be reduced And lead to poor dispersibility, lead to insufficient fuel economy, wearability and elongation at break.

Cis-content (cis- -1,4- butadiene unit content) used herein and contents of ethylene (1,2- butadiene list First content) it can be measured by infrared absorption spectrum.Weight average molecular weight (Mw) and number-average molecular weight (Mn) can use solidifying Glue penetration chromatography (GPC) (the GPC-8000 series manufactured by TOSOH company, detector: differential refractometer, chromatographic column: by The TSKGEL SUPERMULTIPORE HZ-M of TOSOH company manufacture) it is measured by standard of polystyrene.

On the basis of 100 mass % rubber components, the content of the modification low cis BR for silica be 8 mass % with On, preferably 10 mass % or more, more preferably 12 mass % or more.If the content is lower than 8 mass %, will be unable to be enabled People satisfied fuel economy and wearability.Correspondingly, content is 40 mass % hereinafter, preferably 30 mass % are hereinafter, more Preferably 20 mass % or less.If the content is more than 40 mass %, wearability and elongation at break tend to reduce.

The example of other BR includes but is not limited to, public commonly used in those of tire industry, including high-cis BR such as ZEON The BR150B for taking charge of the BR1220 of manufacture and being manufactured by Ube Industries, Ltd；Include 1,2- syndiotactic polybutadiene crystal BR (SPB), the VCR412 and VCR617 such as manufactured by Ube Industries, Ltd；With the polybutadiene for using rare earth catalyst to synthesize Alkene rubber (BR of rare earth catalyst).Other examples include the tin that modified polybutadiene rubber is for example modified by tin compound Modified polybutadiene rubber (tin modification BR (the modification BR for carbon black)) (for example, the tin modification BR being polymerize with lithium initiator, Vinyl binding capacity is that 5-50 mass %, Mw/Mn are 2.0 hereinafter, the content of tin atom is 50-3000ppm).Particularly, rare earth The BR of catalysis is preferred.

Since the BR of rare earth catalyst has cis-content high, contents of ethylene is low, weight average molecular weight (Mw) and the equal molecule of number The low feature of the ratio (Mw/Mn) of (Mn) is measured, therefore it not only has good wearability while being capable of providing good fuel warp Ji property, elongation at break and cracking growth resistance.However, although it has very high compatibility with carbon black, rare earth catalyst BR and silica have lower compatibility.In order to solve this problem, if for silica modification low cis BR with The BR of rare earth catalyst is applied in combination, then the BR due to rare earth catalyst is with the modification low cis BR for silica with close Chemical composition, therefore they can form a phase.Therefore, there is the changing for silica compared with high-compatibility with silica Property low cis BR silica is well dispersed into BR phase, while having with carbon black and being urged compared with the rare earth of high-compatibility The BR of change is well dispersed into carbon black in BR phase.Due to the combination of above two BR, so that silica and carbon black Can disperse well and be distributed in BR phase simultaneously, thus lead to good wearability, fuel economy, wet grip performance and Elongation at break, especially good wearability.

Next, the polybutadiene rubber (BR of rare earth catalyst) that description is synthesized using rare earth catalyst.

The BR of rare earth catalyst refers to the polybutadiene rubber synthesized using rare earth catalyst, has cis-content height, second The low feature of amount vinyl content.As the BR of rare earth catalyst, the product of usual purpose used in Tire production can be used.

Rare earth catalyst can be known one kind, example include containing lanthanide rare compound, organo-aluminum compound, The catalyst of aikyiaiurnirsoxan beta or halogen contained compound, optionally has lewis base.In these, particularly preferably to contain neodymium (Nd) Nd catalyst of the compound as lanthanide rare compound.

The example of lanthanide rare compound includes halide, and carboxylate, alkoxide, thioalkoxide and atomic number are 57- The amide of 71 rare earth metal.As described above, in these, preferred Nd catalyst because its allow with high cis-contents and The generation of the BR of low vinyl content.

The example of organo-aluminum compound includes such as AlR^aR^bR^cCompound represented, wherein R^a, R^bAnd R^cIt is mutually the same or not Together, each to represent hydrogen or the alkyl with 1-8 carbon atom.The example of aikyiaiurnirsoxan beta includes Cyclic aluminoxane and non-annularity alumina Alkane.The example of halogen contained compound includes such as AlX^kR^d _3-kShown in aluminum halide, wherein X represents halogen；R^dRepresent C1-20 alkyl, Aryl or aralkyl；K represents 1,1.5,2 or 3；Halogenation strontium such as Me₃SrCl,Me₂SrCl₂,MeSrHCl₂And MeSrCl₃；And gold Belong to halide such as silicon tetrachloride, tin tetrachloride and titanium tetrachloride.Lewis base is suitable for lanthanide rare compound to be complexed Example includes acetylacetone,2,4-pentanedione, ketone and alcohol.

In polymerized butadiene, rare earth catalyst can be in organic solvent (for example, n-hexane, hexamethylene, normal heptane, first Benzene, dimethylbenzene and benzene) in solution form using or with being supported on suitable carrier (for example, silica, magnesia and chlorination Magnesium) on form use.About polymerizing condition, polymerization can be polymerisation in solution or bulk polymerization, and polymerization temperature is preferably -30 ~150 DEG C, polymerization pressure can be suitably selected according to other conditions.

The weight average molecular weight (Mw) of the BR of rare earth catalyst and the ratio (Mw/Mn) of number-average molecular weight (Mn) be preferably 1.2 with On, more preferably 1.5 or more.If the ratio is lower than 1.2, processability tends to deteriorate significantly.Ratio Mw/Mn is preferably 5 Hereinafter, more preferably 4 hereinafter, still more preferably 3 hereinafter, especially preferably 2 hereinafter, most preferably 1.9 or less.If this ratio Rate is more than 5, then the effect of improve wearability tends to reduce.

The Mw of the BR of rare earth catalyst is preferably 200,000 or more, more preferably 250,000, but its be preferably 900,000 with Under, more preferably 600,000 or less.In addition, the Mn of the BR of rare earth catalyst is preferably 100,000 or more, more preferably 150,000 More than, but it is preferably 800,000 hereinafter, more preferably 700, and 000 or less.If Mw or Mn is less than above-mentioned lower limit value, wear-resisting Property tend to reduce and fuel economy aggravate.If Mw or Mn is more than the above-mentioned upper limit, processability may be poor.

The cis-content of the BR of rare earth catalyst is preferably 90 mass % or more, more preferably 93 mass % or more, more excellent It is selected as 95 mass % or more.If its cis-content is lower than 90 mass %, wearability can be lowered.

The contents of ethylene of the BR of rare earth catalyst is preferably 1.8 mass % hereinafter, more preferably 1.0 mass % are hereinafter, more Add preferably 0.5 mass % hereinafter, especially preferably 0.3 mass % or less.If its contents of ethylene is more than 1.8 matter % is measured, wearability can be lowered.

In the case where rubber composition according to the present invention includes the BR of rare earth catalyst, with the rubber group of 100 mass % It is divided into benchmark, the content of the BR of rare earth catalyst is preferably 5 mass % or more, more preferably 10 mass % or more, more preferably 12 mass % or more.If its content is lower than 5 mass %, satisfied wearability and elongation at break can not be obtained.Its content is excellent 40 mass % are selected as hereinafter, more preferably 35 mass % are hereinafter, more preferably 30 mass % or less.If its content is more than 40 Quality % can not obtain satisfied fuel economy and wearability.

In rubber composition of the invention, on the basis of 100 mass % rubber components, the content of BR be 8 mass % with On, preferably 10 mass % or more, more preferably 15 mass % or more.If its content is lower than 8 mass %, wearability can be reduced. BR content is preferably 60 mass % hereinafter, more preferably 55 mass % or less.If its content is more than 60 mass %, wet adherence properties Can, processability and elongation at break EB will be deteriorated.

Rubber components in rubber composition according to the present invention include butadiene-styrene rubber (SBR).It is capable of providing good Wet grip performance, fuel economy and antireversion.

SBR is not particularly limited, and example includes the SBR (E-SBR) of emulsion polymerization, the SBR (S-SBR) of polymerisation in solution (it has been used can be with silica phase interaction with the modified styrene butadiene rubber (the modification SBR for silica) for silica It is compound modified).Particularly, the E-SBR and modification SBR for silica is preferred, the combination of these SBR is more Preferably.E-SBR has a high proportion of high molecular weight component and is capable of providing outstanding wearability and elongation at break.It is another Aspect, the modification SBR and silica Degree of interaction for silica are high, therefore allow the good dispersion of silica To improve fuel economy and wearability.

Next, specifically describing E-SBR.

E-SBR is not particularly limited, and can be used commonly used in those of in tire industry.

In the case where rubber composition according to the present invention includes E-SBR, on the basis of 100 mass % rubber components, The content of E-SBR is preferably 10 mass % or more, more preferably 30 mass % or more.If its content is lower than 10 mass %, nothing Method obtains satisfied wearability, elongation at break and processability.The content of E-SBR is preferably 70 mass % hereinafter, more preferably 60 mass % or less.If its content is more than 70 mass %, fuel economy and wearability tend to reduce.

Next, by description with silica can be used for what the compound of silica interaction be modified Modified styrene butadiene rubber (the modification SBR for silica).

Modification SBR for silica can be by replacing the above-mentioned modification BR for silica with butadiene-styrene rubber In skeleton structure, that is, polybutadiene rubber prepared by.Particularly, for the modification SBR of silica preferably with such as formula (1) the modified butadiene rubber of compound represented (the modified SBR of S-), and suitable solution polymerization styrene-butadiene rubber (S-SBR), Its polymerizable end (reactive terminal) is modified (modified S-SBR (the patent document JP 2010- of S- with formula (1) compound represented Modified SBR described in 111753).

In the present invention, the styrene of the modification SBR for silica is preferably 40 mass % hereinafter, more preferably For 35 mass % hereinafter, more preferably 30 mass % or less.If styrene is more than 40 mass %, fuel economy meeting Deterioration.It is also preferably 15 mass % or more, more preferably 23 matter for the styrene in the modification SBR of silica Measure % or more.If the styrene is lower than 15 mass %, wet grip performance tends to be poor.

Styrene-content passes through H¹The measurement of-NMR method.

In the case where rubber composition according to the present invention includes the modification SBR for silica, with 100 mass % rubbers On the basis of glue component, the content of the modification SBR for silica is preferably 8 mass % or more, more preferably 15 mass % with On, more preferably 20 mass % or more.If the content is lower than 8 mass %, satisfied wet grip performance and fuel can not be obtained Economy.The content be preferably also 80 mass % hereinafter, more preferably 75 mass % hereinafter, more preferably 72 mass % hereinafter, Especially preferably 70 mass % or less.If the content is more than 80 mass %, wearability and fuel economy tend to reduce.

In rubber composition of the invention, on the basis of 100 mass % rubber components, the content of SBR be 25 mass % with On, preferably 30 mass % or more, more preferably 35 mass % or more.If the content is lower than 25 mass %, wet grip performance It can deteriorate with antireversion.The content of SBR is also 75 mass % hereinafter, preferably 72 mass % are hereinafter, more preferably 70 matter Measure % or less.If the content be more than the content of 75 mass %, mixed NR and BR can reduce obtain it is satisfied resistance to Mill property and processability (in the case where NR).

In addition to BR and SBR, the example of other rubber materials in rubber composition for use in the present invention includes diene Class rubber such as natural rubber (NR), epoxy natural rubber (ENR), polyisoprene rubber (IR), high-purity natural rubber (phosphorus Content is 200ppm HPNR below), 3,4- polyisoprene rubbers (3,4-IR), styrene isoprene butadiene rubber (SIBR) (SIBR), neoprene (CR) and nitrile rubber (NBR).It may include other rubbers in addition to polydiene in rubber components Glue material (for example, ethylene propylene diene rubber (EPDM) and butyl rubber (IIR)).These rubber materials can be used alone or Person is used in combination.Preferred NR in these, because it is capable of providing good elongation at break.

Rubber composition according to the present invention includes that N2 adsorption specific surface area is 160-270m²The silica of/g, i.e., it is micro- Powder silica.The fine particle silica can be used alone or be used in combination.

N2 adsorption specific surface area (the N of fine particle silica₂It SA) is preferably 170m²/ g or more, more preferably 195m²/ g with On, more preferably 210m²/ g or more.If the N2 adsorption specific surface area is less than 160m²/ g, wet grip performance, elongation at break and Wearability (especially wearability) will tend to be enhanced with being unable to fully, because such silica is in enhancing polymer substrate In effect it is poor, lead to the formation of a small amount of filler gel, to influence wearability and fracture tensile strength.Its N2 adsorption compares table Area is preferably 260m²/ g is hereinafter, more preferably 250m²/ g or less.If its N2 adsorption specific surface area is more than 270m²/ g, in this way Silica itself have it is very strong from reunite tendency, to tend to the dispersibility for having poor, lead to fuel economy, break Split the reduction of elongation and wearability.

Herein, the N of silica₂SA value is measured according to ASTM D3037-81 standard by BET method.

Relative to 100 mass parts rubber components, the content of fine particle silica is 40 mass parts or more, preferably 50 mass Part or more.If the content is lower than 40 mass parts, fuel economy, wet grip performance, the improvement of elongation at break and wearability Effect can be insufficient.Below the mass for 120, preferably 110 below the mass, and more preferably 105 below the mass for the content, More preferably 100 below the mass.If the content is more than 120 mass parts, the dispersibility of fine particle silica is poor, will lead to The reduction of fuel economy, elongation at break and wearability.

In rubber composition according to the present invention, preferably silane coupling agent and silica composition are used.Particularly, sulfydryl Silane coupling agent is preferred.In view of wearability, mercaptosilane coupling agents be preferably as with traditional Si266 and Si69 is compared, even if they are also able to maintain the coupling between silica and polymer applying frictional force on road surface.Make In the case where BR with rare earth catalyst, polymer molecule tight agglomeration itself and with Si266 or Si69 have lower combination Intensity, but they and mercaptosilane coupling agents form firm combination.

The suitable example of silane coupling agent comprising sulfydryl (- SH) includes such as formula (I) compound represented and contains formula (II) compound of connection unit B shown in connection unit A shown in and formula (III):

Wherein, R¹⁰¹To R¹⁰³Each representative has branch or unbranched C1-12 alkyl, there is branch or unbranched C1-12 Alkoxy, or-O- (R¹¹¹-O)_z-R¹¹², wherein z R¹¹¹Respectively representing has branch or unbranched C1-30 bivalent hydrocarbon radical, Z R¹¹¹It can be the same or different from each other.R¹¹²Representative has branch or unbranched C1-30 alkyl, there is branch or unbranched C2- 30 alkenyls, C6-30 aryl or C7-30 aralkyl, and z represents the integer of 1-30, R¹⁰¹To R¹⁰³It can be the same or different from each other； R¹⁰⁴Representative has branch or unbranched C1-6 alkylene.

Wherein, R²⁰¹Hydrogen is represented, halogen has branch or unbranched C1-30 alkyl, there is branch or unbranched C2-30 chain Alkenyl, the alkyl for thering is branch or unbranched C2-30 alkynyl or its end hydrogen to be substituted by hydroxy or carboxy, R²⁰²Representative has branch Or unbranched C1-30 alkylene, there are branch or unbranched C2-30 alkenylene, or have branch or the unbranched Asia C2-30 alkynes Base, R²⁰¹And R²⁰²Ring structure can be formed together.

The example of formula (I) compound represented includes 3- mercaptopropyl trimethoxysilane, 3- mercaptopropyltriethoxysilane, 2- mercapto ethyl trimethoxy silane, compound representated by 2- mercaptoethyltriethoxysilane and following formula is (by EVONIK- The Si363 of DEGUSSA manufacture).Compound representated by following formula can be used suitably.These compounds can be used alone or It is used in combination.

Next, the chemical combination by description containing connection unit B shown in connection unit A shown in formula (II) and formula (III) Object.In the silane coupling agent with this structure, it is contemplated that enhancing prevents viscosity from increased effect and preventing during processing Scorch time is reduced, and the content of connection unit A is preferably 30 moles of % or more, more preferably 50 moles of % or more, while also excellent 99 moles of % are selected as hereinafter, more preferably 90 moles of % or less.In addition, the content of connection unit B is preferably 1 mole of % or more, More preferably 5 moles of % or more, more preferably 10 moles of % or more, while preferably also 70 moles of % are hereinafter, more preferably 65 Mole % is hereinafter, more preferably 55 moles of % or less.In addition, the combined amount of connection unit A and B are preferably 95 moles of % or more, It is more preferably 98 moles of % or more, especially preferably 100 moles of %.

It should be noted that the content of connection unit A or B are to include the connection unit A or B being located at end of silane The content of (if present).If connection unit A or B are located at end of silane, their form is not special Ground limits, as long as they form the unit for corresponding to the formula (II) and (III) that respectively represent connection unit A and B.

For R²⁰¹The example of halogen include chlorine, bromine and fluorine.For R²⁰¹Have branch or unbranched C1-30 alkyl Example includes methyl and ethyl.The carbon atom number of the alkyl is preferably 1-12.For R²⁰¹Have branch or unbranched C2-30 Alkenyl includes vinyl and 1- acrylic, and the carbon atom number of the alkenyl is preferably 2-12.For R²⁰¹Have branch or without branch The example of the C2-30 alkynyl of chain includes acetenyl and propinyl.The carbon atom number of the alkynyl is preferably 2-12.For R²⁰²Have The example of branch or unbranched C1-30 alkylene includes a vinyl and acrylic.The carbon atom number of the alkylene is preferred For 1-12.For R²⁰²The example for having the alkenylene of branch or unbranched C2-30 include ethenylidene and 1- allylidene. The carbon atom number of the alkenylene is preferably 2-12.For R²⁰²Have the example of branch or unbranched C2-30 alkynylene include Asia Acetenyl and sub- propinyl, the carbon atom number of the alkynylene is preferably 2-12.

In the compound comprising connection unit B shown in connection unit A shown in formula (II) and formula (III), formula (II) institute Total number of repetition (x+y) of the number of repetition y of connection unit B shown in the number of repetition x and formula (III) of the connection unit A shown is excellent Selecting range is 3-300.Gross weight is scolded again in above range, and the hydrosulphonyl silane of connection unit B is connected the-C of unit A₇H₁₅ Part is covered, can be in the reduction for ensuring with preventing scorch time while silica or rubber components good reactivity.

The example of compound comprising connection unit B shown in connection unit A shown in formula (II) and formula (III) includes NXT-Z30, NXT-Z45, and NXT-Z60 (are manufactured) by MomentivePerformanceMaterials.These compounds can be used alone or It is used in combination.

In addition, can be suitably using compound representated by following formula:

Relative to the silica of 100 mass parts, silane coupled agent content is preferably 1 mass parts or more, more preferably 3 matter Measure part or more.If the content is lower than 1 mass parts, wearability, elongation at break and sticky (processability) aggravate.Silane is even The content of connection agent is preferably also 15 below the mass, and more preferably 12 below the mass.If the content is more than 15 mass parts, become In the effect proportional to increased costs cannot be obtained.

It is 100-250m that rubber composition according to the present invention, which preferably comprises N2 adsorption specific surface area,²The carbon black of/g, that is, micro- Burgy is black.The micro mist carbon black can be used alone or be used in combination.

N2 adsorption specific surface area (the N of micro mist carbon black₂It SA) is preferably 120m²/ g or more, more preferably 140m²/ g or more.Such as Its N of fruit₂SA is less than 100m²/ g tends to that satisfied elongation at break and wearability can not be obtained.Its N₂SA is preferably 200m²/ g with Under, more preferably 180m²/ g or less.N₂SA is more than 250m²The carbon black of/g tends to the dispersibility for having poor, leads to fuel economy Property, elongation at break and wearability reduce.

The N of carbon black herein₂SA is according to JIS K 6217-2:2001 standard test.

Relative to 100 mass parts rubber components, the content of micro mist carbon black is preferably 1 mass parts or more, more preferably 3 mass Part or more.If the content is lower than 1 mass parts, the addition of this carbon black does not have effect.In addition, it can not also prevent rubber UV degradation.The content is preferably also 50 below the mass, and more preferably 40 below the mass, more preferably 30 mass parts with Under.If the content is more than 50 mass parts, satisfied fuel economy and elongation at break can not be obtained.

Rubber composition of the invention may include aluminium system inorganic filler such as aluminium hydroxide.Aluminium hydroxide does not limit particularly It is fixed, it can be commonly used in that in tire industry.The average primary particle diameter of aluminium hydroxide is preferably 0.3-10 μm, more preferably It is 0.6-3 μm.

Rubber composition of the invention preferably comprises sulphur.The example of sulphur includes powder sulphur, precipitated sulfur, and sulikol is insoluble Sulphur and polymolecularity sulphur.

Relative to the rubber components of 100 mass parts, the content of sulphur is preferably 0.5 mass parts or more, more preferably 0.7 mass Part or more.The content of sulphur is preferably also 2 below the mass, and more preferably 1.7 below the mass.When the content of sulphur falls in above-mentioned model When enclosing interior, effect of the invention can be more suitably implemented.

If softening point is that -20~45 DEG C of liquid resin is used in rubber composition of the invention, due to resin sheet Body has good dispersibility and can lubricate the polymer chain of diene rubber (BR, SBR) suitably to be the poly- of diene rubber It closes and provides lubricity appropriate between object chain and fine particle silica or micro mist carbon black or sulphur.Fine particle silica, micro mist charcoal Black and sulphur can be evenly dispersed in entire rubber composition in kneading step.Further, since sulphur is uniformly dispersed, gather Adduct molecule can equably be cross-linked to each other in vulcanisation step.

As described above, when the liquid resin with specific softening point is used in rubber composition of the invention, micro mist The dispersibility of silica and micro mist carbon black is further improved, meanwhile, polymer molecule is equably cross-linked to each other.Therefore, may be used Good elongation at break, therefore fuel economy, wet grip performance are obtained, the balance between elongation at break and wearability changes It is kind to be implemented.

Particularly, when the liquid coumarone-indene resin with specific softening point is used as liquid resin, the resin and sulphur (oxygen atom and sulphur that are especially contained in liquid coumarone-indene resin) is attracted one another by Van der Waals force, so that the table of sulphur Face is coated by the resin, to (can reduce the tendency reunited) with reduced surface.So surface and diene due to sulphur The difference of SP value between rubber is reduced, and the dispersibility of sulphur is significantly improved.In addition, since resin itself has good point It dissipates property and lubricates the polymer chain of diene rubber, therefore sulphur is spread more evenly across in entire rubber composition in kneading step In, and polymer molecule is more uniformly cross-linked to each other in vulcanisation step.Therefore, the effect for improving above-mentioned performance can be more preferable It realizes on ground.

As described above, rubber composition of the invention preferably comprises the liquid resin that softening point is -20~45 DEG C.The liquid Resin is preferred for substitution oil.

Liquid resinous softening point is -20 DEG C or more, preferably -10 DEG C or more.If softening point is lower than -20 DEG C, cannot Fully obtain the effect for improving fuel economy and elongation at break.Softening point be also 45 DEG C hereinafter, preferably 40 DEG C hereinafter, If softening point is higher than 45 DEG C, fuel economy, elongation at break and wearability can be deteriorated.

Liquid resinous softening point, which refers to, to be provided by ring and ball softening point measuring instrument in JIS K 6220-1:2001 standard Softening point measurement in, ball falls the temperature at place.

Liquid resin is not particularly limited, and only its softening point is within the above range.Liquid resinous example packet Including aromatic liquid resin (or anime with above-mentioned softening point range) for example especially has above-mentioned softening point range Coumarone-indene resin；Liquid terpene resin (or terpene resin with above-mentioned softening point range)；And liquid rosin resin (or rosin resin with above-mentioned softening point range).Particularly, aromatic liquid resin is as being especially liquid coumarone-indene resin It is that preferably, liquid coumarone-indene resin is it is furthermore preferred that because they can make effect of the invention with liquid terpene resin More suitably realize.

Anime refers to the resin obtained by polymerizeing C8-10 fragrance fraction, is usually fissioned by naphtha It obtains and including vinyltoluene, indenes and methyl indenes as principal monomer.Here, other components in anime include benzene Ethylene and homologues such as α-methylstyrene and Beta-methyl styrene.Anime also may include aliphatic olefin list Member, phenol units and/or cresols unit.

The example of anime includes coumarone-indene resin, and indene resin, aromatic ethylene polymer is (by polymerizeing Alpha-Methyl The resin that styrene and/or styrene obtain) and C9 hydrocarbon resin.In these, preferred coumarone-indene resin, because it can make Effect of the invention is more suitably realized.That is, the coumarone-indene resin with above-mentioned softening point range is preferred.

Coumarone-indene resin refers to the monomeric unit comprising coumarone and indenes as the skeleton (main chain) for forming the resin Resin.Other than coumarone and indenes, the example for the monomeric unit that can be comprised in its skeleton includes styrene, Alpha-Methyl benzene Ethylene, methyl indenes and vinyltoluene.

The example of terpene resin includes polyterpene resin and terpene phenol resin.Polyterpene resin is preferred.In other words, Liquid terpene resin is preferably liquid terpene resin (polyterpene resin with above-mentioned softening point range).

Polyterpene resin includes resin and its hydrogenated products as made from polymerization terpene compound.Terpene compound packet Include formula (C₅H₈) hydrocarbon and its containing oxygen derivative representated by n.Terpene compound, which has, is divided into monoterpene (C₁₀H₁₆), sequiterpene Alkene (C₁₅H₂₄), di-terpene (C₂₀H₃₂) etc. terpenes basic framework.The example of terpene compound includes α-sobrerone, β-sobrerone, and two Amylene, limonene, laurene, alloocimene, ocimenum, α-phellandrene, α-terpinenes, γ-terpinenes, terpinolene, 1,8- Cineole, 1,4- cineole, α-terpineol, β-terpineol, and γ-terpineol.

The example of polyterpene resin includes by above-mentioned any terpene compound such as α-sobrerone resin, β-sobrerone resin, lemon Terpene resin made from lemon olefine resin, diamyl olefine resin and β-sobrerone/limonene resin, and by carrying out hydrogen to terpene resin Hydrogenated terpene resin obtained from change.In these, preferred limonene resin, because it is capable of providing good wet adherence properties Energy.

The example of terpene phenol resin includes the resin as made from above-mentioned terpene compound and phenolic compound.Its specific example Including by terpene compound, phenolic compound and formalin condensed prepared by resin.The example of phenolic compound Attached bag includes phenol, bisphenol-A, cresols and dimethlbenzene.

Relative to 100 mass parts rubber components, liquid resinous amount is preferably 0.5 mass parts or more, more preferably 1 mass Part or more.If the content is lower than 0.5 mass parts, improvement fuel economy is obtained with being unable to fully, elongation at break and wear-resisting The effect of property.Liquid resinous content is preferably also 20 below the mass, and more preferably 10 below the mass, more preferably 5 matter Measure part or less.If the content is more than 20 mass parts, complex modulus (E*) and hardness can be lowered.

Rubber composition of the invention preferably comprises at least a kind of selected from the terpenes tree for being 46~160 DEG C by softening point Rouge, the rosin resin that softening point is 46~140 DEG C, the C5 Petropols and softening point that softening point is 46~140 DEG C are 46~140 DEG C anime constitute combination in resin.Although present invention uses the relatively high wet grip performances that can lead to of content to drop Low BR, but the use of these rubber provides good wet grip performance, and fuel economy, wet grip performance, fracture Elongation and wearability can more suitably be improved.This may be because these resins are distributed with 100nm-1 μm of spherical form In rubber components, thus tire grab ground when provide it is physical grab (for example, when road surface have higher temperature when, pass through Make resin melting to generate anchoring effect or adherent zone effect).

It is preferably terpene resin or anime selected from least one of said combination resin.Terpene resin is improving It is efficient in wet grip performance and fuel economy, and anime is efficient in improving wet grip performance.

Relative to 100 mass parts rubber components, the combined content of the resin in said combination is preferably 1 mass parts More than, more than more preferably 3 mass parts, more than more preferably 7 mass parts.A combination thereof content be also preferably 20 below the mass, More preferably 15 below the mass, and more preferably 12 below the mass.When a combination thereof content is fallen within the above range, fuel warp Ji property, wet grip performance, elongation at break and wearability can suitably be improved.

Softening point is that 46~160 DEG C of terpene resin is only different from above-mentioned liquid terpene resin in terms of softening point.It should Terpene resin may suitably be polyterpene resin or terpene phenol resin, be more suitably terpene phenol resin.

It is preferred that polyterpene resin is limonene resin, because it is capable of providing outstanding grip performance.In the present invention, in addition to Except terpene compound, terpene resin (polyterpene resin, terpene phenol resin) may include a small amount of other monomers such as Alpha-Methyl benzene Ethylene is as monomeric unit.For example, phenolic compound and a small amount of α-methylstyrene are made as monomer by terpene compound Resin be included in terpene phenol resin.

The softening point of terpene resin is preferably 46 DEG C or more, more preferably 80 DEG C or more, more preferably 100 DEG C or more.Such as Its softening point of fruit is lower than 46 DEG C, and the effect for improving wet grip performance can be lowered.Its softening point is preferably also 160 DEG C hereinafter, more Preferably 135 DEG C or less.If its softening point is more than 160 DEG C, such resin can have the dispersibility of reduction, and fracture is caused to be stretched Long rate and wearability reduce.

In the case where only terpene resin is used as selected from least one of said combination resin, terpene resin it is excellent Choosing amount is the combined content of the above-mentioned resin in said combination.

Softening point is that 46~140 DEG C of anime refers to that the softening point obtained by polymerization C8-C10 fragrance fraction is 46 ~140 DEG C of resin is usually fissioned by naphtha and is obtained and including vinyltoluene, indenes and methyl indenes as main single Body.Here, the other components in fragrant fraction include the homologue such as α-methylstyrene and Beta-methyl of styrene and styrene Styrene.Anime also may include coumarone unit.Anime also may include fatty olefin unit, phenol units and/or Cresols unit.

The softening point of anime is 46 DEG C or more, preferably 60 DEG C or more, more preferably 70 DEG C or more, more preferably 80 DEG C, and especially preferably 90 DEG C or more.If its softening point is lower than 46 DEG C, the effect for improving grip performance can be lowered.This Outside, softening point is 140 DEG C hereinafter, preferably 130 DEG C or less.If softening point is more than 140 DEG C, such resin can have drop Low dispersibility causes elongation at break and wearability to reduce.

The example of anime includes coumarone-indene resin, and indene resin, aromatic ethylene polymer is (by polymerizeing Alpha-Methyl The resin that styrene and/or styrene obtain) and C9 hydrocarbon resin.Particularly, coumarone-indene resin, indene resin and aromatic ethylene Polymer is that preferably, coumarone-indene resin and aromatic ethylene polymer are it is furthermore preferred that because they can evenly improve Fuel economy, wet grip performance, elongation at break and wearability.Further preferably coumarone-indene resin is polymerize with aromatic ethylene Object is applied in combination.

The coumarone-indene resin of the above-mentioned example as anime is only fragrant with previously mentioned liquid in terms of softening point Beans ketone-indene resin is different.It is used as at only coumarone-indene resin (anime) selected from least one of said combination tree In the case where rouge, the preferred amounts of coumarone-indene resin are the combined content of the above-mentioned resin in said combination.

Aromatic ethylene polymer is formed by styrene and/or α-methylstyrene as aromatic vinyl monomers (unit).Virtue Fragrant ethene polymers can be the homopolymer of each of these monomers or the copolymer of two kinds of monomers.Aromatic ethylene polymerization Object is preferably the homopolymer of α-methylstyrene or styrene or the copolymer of α-methylstyrene and styrene, more preferably The copolymer of α-methylstyrene and styrene is capable of providing good wet adherence properties because it is environmental protection and is easily handled Energy.

As aromatic ethylene polymer, commercial product can be suitably used, such as the manufacture of Arizona chemical company SYLVARES SA85, SA100, SA120 and SA140, the R2336 of Eastman Chemical Company's production.

The softening point of aromatic ethylene polymer is preferably 46 DEG C or more, more preferably 60 DEG C or more, more preferably 70 DEG C with On.If its softening point is lower than 46 DEG C, wet grip performance can be reduced.The softening point is preferably also 140 DEG C hereinafter, more preferably 100 DEG C or less.If softening point is higher than 140 DEG C, fuel economy can deteriorate.

Terpene resin, rosin resin, C5 Petropols, anime and aromatic ethylene polymer softening point each refer to By ring and ball softening point measuring instrument in the softening point measurement as defined in JIS K 6220-1:2001 standard, ball falls the temperature at place Degree.

In the case where only aromatic ethylene polymer is used as selected from least one of said combination resin, fragrant second The preferred amounts of alkene polymer are the combined content of the above-mentioned resin in said combination.

It is -20~45 DEG C of liquid coumarone-indene resins and softening point that rubber composition of the invention, which preferably comprises softening point, For the combination of 46~140 DEG C of anime, because this allows effect of the invention more suitably to realize.

In addition to the above components, rubber composition of the invention can suitably include and prepare commonly used in rubber composition In compounding agent, including, for example, processing aid such as zinc oxide, stearic acid and fatty acid metal salts, a variety of antioxidants, wax, Oil, vulcanizing agent and vulcanization accelerator.

It is oily relative to 100 mass parts rubber components from the point of view of fully realizing effect of the invention, liquid resin, It is preferably 2-35 mass parts with the combined content selected from least one of said combination resin.From improve fuel economy and From the point of view of wearability, which is more preferably 3-15 mass parts.

Rubber composition of the invention can be prepared by conventional method.Specifically, rubber composition can be for example, by such as The preparation of lower section method: Banbury mixer is used, kneader, open roll mill etc. mediates component, then to mixture Vulcanized.The rubber composition can be suitably used for tire tread.

More specifically, to rubber components, silica, carbon black, silane coupling agent etc. mediated until discharge temperature Reaching 120~180 DEG C, (preferably 130~175 DEG C (are about 150 DEG C when silane coupling agent is Si266；When silane coupling agent is It is about 170 DEG C when NXT；It is about 140 DEG C when silane coupling agent is NXTZ or Si363) (basic kneading step).Next, will Vulcanizing agent such as sulphur, vulcanization accelerator etc. be added mixture in, then when kneader is cooled, about 50 DEG C at a temperature of start Mediate, when kneader is used continuously, about 80 DEG C at a temperature of start to mediate, it is then lasting to carry out until temperature is finally discharged Degree reaches about 110~120 DEG C (final kneading steps).Then kneaded mixture is vulcanized, thus can be made of the invention Rubber composition.Preferably, basic kneading step is above in two steps executes.Further, each step in basic kneading step In, silica and silane coupling agent are preferably added batch-wise and mediate.It is highly preferred that rubber components, carbon black, part of silica It is kneaded first with the first step of the part silane coupling agent in basic kneading step, remaining chemical reagent is in subsequent step In be added and mediate.For example, in the case where basic kneading step is made of two steps, the rubber components and charcoal of whole amount Black and half amount silica and the silane coupling agent of half amount can be added and mediate in the first step, the dioxy of surplus SiClx and silane coupling agent and other chemical reagent can be added to the kneaded mixture obtained in the first step in second step In and mediated.In this way, the dispersibility of silica can further improve.

Above-mentioned rubber composition can be used to manufacture by conventional method for pneumatic tire of the invention.

Specifically, the rubber composition comprising said components, before vulcanization, according to the shape quilt of tyre assembly such as tyre surface It squeezes out and processing forms to be made not in the usual way together with other tyre assemblies then on Tire production machine Vulcanized tyre.The unvulcanized tire is heated and pressurized to form tire in vulcanizer.

Pneumatic tire of the invention can be used as the tire for passenger car, for the tire of truck and bus, be used for The tire of sports utility vehicle (SUVs), racing-car tyre etc., the particularly suitable tire for acting on passenger car and be used for sports type The tire of multi-function vehicle.

Embodiment

The present invention will be more specifically described by embodiment, but the present invention is not limited to these Examples.

(preparation of chain end modifying agent)

Under nitrogen protection, 20.8g 3- (N, N '-dimethylamino) propyl trimethoxy silicane is packed into 250ml measuring bottle (AZmax Co., Ltd.) and anhydrous hexane (Kanto Kagaku K. K.) make its total amount reach 250ml, and chain end is thus made and changes Property agent.

(copolymer preparation 1)

It is packed into 18L hexamethylene (Kanto Kagaku K. K.) to through the sufficiently cleaned up compression resistanted container of nitrogen (30L) is middle, Temperature is risen to 60 by 2000g butadiene (Gao Qiansui business Co., Ltd.), the diethyl ether (Kanto Kagaku K. K.) of 53mmol ℃.Next, the butyl lithium (commercial firm, Kanto Kagaku K. K.) of 16.6ml is added in mixture, it is followed by stirring for 3 hours.So 12ml 0.4mol/L silicon tetrachloride/hexane solution is added afterwards, is followed by stirring for 30 minutes.Then 13ml chain end modifying agent is added, It is followed by stirring for 30 minutes.It (is closed methanol of the 2ml dissolved with 0.2g 2,6- Butylated Hydroxytoluene (Japanese God Light chemical company) is added Eastern Chemical Co., Ltd.) after, reaction solution is transferred in the rustless steel container equipped with 18L methanol, and collect group obtained Polymers.Aggregate is dried under reduced pressure 24 hours so that modified BR is made.The Mw of modification BR is 420,000 and contents of ethylene is 13 Quality %.

(copolymer preparation 2)

To through being packed into 18L the n-hexane, (Northeast chemistry strain of 540g styrene in the sufficiently cleaned up compression resistanted container of nitrogen (30L) Formula commercial firm), temperature is risen to 40 DEG C by the tetramethylethylenediamine of 1460g butadiene and 17mmol.Next, will The silicon tetrachloride of 3.5ml0.4mol/L/hexane solution is added in mixture, is followed by stirring for 30 minutes.Then by the fourth of 10.5ml Base lithium is added in mixture, and temperature is then risen to 50 DEG C, is followed by stirring for 3 hours.Then 30ml chain end modifying agent is added, It is followed by stirring for 30 minutes.2ml is added dissolved with the methanol (Northeast of 0.2g 2,6- Butylated Hydroxytoluene (Japanese God Light chemical company) Chemical Co., Ltd.) after, reaction solution is transferred in the rustless steel container equipped with 18L methanol, and collect obtained reunite Object.Aggregate is dried under reduced pressure 24 hours so that modified SBR is made.Styrene in modification SBR is 27 mass %, Mw For 400,000 and contents of ethylene is 53mol%.

(copolymer preparation 3)

To through being packed into 18L the n-hexane, (Northeast chemistry strain of 740g styrene in the sufficiently cleaned up compression resistanted container of nitrogen (30L) Formula commercial firm), temperature is risen to 40 DEG C by the tetramethylethylenediamine of 1260g butadiene and 17mmol.Next, will The silicon tetrachloride of 3.5ml0.4mol/L/hexane solution is added in mixture, is followed by stirring for 30 minutes.Then by the fourth of 10.5ml Base lithium is added in mixture, and temperature is then risen to 50 DEG C, is followed by stirring for 3 hours.Then 30ml chain end modifying agent is added, It is followed by stirring for 30 minutes.2ml is added dissolved with the methanol (Northeast of 0.2g 2,6- Butylated Hydroxytoluene (Japanese God Light chemical company) Chemical Co., Ltd.) after, reaction solution is transferred in the rustless steel container equipped with 18L methanol, and collect obtained reunite Object.Aggregate is dried under reduced pressure 24 hours so that modified SBR is made.Styrene in modification SBR is 37 mass %, Mw For 410,000 and contents of ethylene is 54mol%.

(copolymer preparation 4)

To through being packed into 18L the n-hexane, (Northeast chemistry strain of 520g styrene in the sufficiently cleaned up compression resistanted container of nitrogen (30L) Formula commercial firm), temperature is risen to 40 DEG C by the tetramethylethylenediamine of 1480g butadiene and 17mmol.Next, will The silicon tetrachloride of 3.5ml0.4mol/L/hexane solution is added in mixture, is followed by stirring for 30 minutes.Then by the fourth of 10.5ml Base lithium is added in mixture, and temperature is then risen to 50 DEG C, is followed by stirring for 3 hours.Then 30ml chain end modifying agent is added, It is followed by stirring for 30 minutes.2ml is added dissolved with the methanol (Northeast of 0.2g 2,6- Butylated Hydroxytoluene (Japanese God Light chemical company) Chemical Co., Ltd.) after, reaction solution is transferred in the rustless steel container equipped with 18L methanol, and collect obtained reunite Object.Aggregate is dried under reduced pressure 24 hours so that modified SBR is made.Styrene in modification SBR is 26 mass %, Mw For 430,000 and contents of ethylene is 56mol%.

Hereinafter, chemical reagent used in embodiment and reference examples is summarized.

NR:TSR20

ENR:ENR25 (epoxy natural rubber, the manufacture of Kumpulan Guthrie Berhad company, the western industry in Malaysia；Epoxy Rate: 25mol%)

The manufacture of BR1:CB25, Lanxess company (BR (BR of Nd catalysis) synthesized with Nd catalyst, cis-content: 97 matter % is measured, contents of ethylene: 0.7 mass %, Mw/Mn:1.78, Mw:500,000, Mn:280,000) BR2:BR150B, space portion is emerging The manufacture of production Co., Ltd. (BR (BR of Co catalysis) synthesized with Co catalyst, cis-content: 96 mass %, contents of ethylene: 2.1 mass %, Mw/Mn:2.30, Mw:440,000, Mn:190,000)

For modified BR obtained in modification BR1: the copolymer preparation 1 of silica (contents of ethylene: 13 mass %, Cis-content: 38 mass %, trans content: 50 mass %, Mw/Mn:1.19, Mw:420,000)

For the modification BR2: modified polybutadiene rubber (the modified BR of S-) of silica, Sumitomo Chemical Co's system It makes.(15 mass % of contents of ethylene；R¹,R²,R³=-OCH₃, R⁴,R⁵=-CH₂CH₃, n=3)

Modification BR:BR1250H, ZERO company manufacture for CB ((is used for carbon black with the tin modification BR of lithium initiator polymerization Modification BR), contents of ethylene: 10 mass %, cis-content: 40 mass %, trans content: 50 mass %, Mw/Mn:1.40, Mw:460,000, Mn:330,000, tin atom content: 250ppm)

For modified SBR (styrene: 27 matter obtained in modification SBR1: the copolymer preparation 2 of silica Measure %)

For modified SBR (styrene: 37 matter obtained in modification SBR2: the copolymer preparation 3 of silica Measure %)

For modified SBR (styrene: 26 matter obtained in modification SBR3: the copolymer preparation 4 of silica Measure %)

E-SBR:SBR1723, JSR Corp. manufacture (styrene: 23.5%)

Carbon black: HP160, Columbia Carbon company manufacture (N₂SA:165m²/g)

Silica 1: Zeosil 1085Gr, Phodia company manufactures (N₂SA:90m²/g)

Silica 2:Zeosil 1115Gr, Phodia company manufactures (N₂SA:115m²/g)

Silica 3:Zeosil 1165MP, Phodia company manufactures (N₂SA:165m²/g)

Silica 4:ULTRASIL VN3, Evonik Degussa company manufactures (N₂SA:175m²/g)

Silica 5:Zeosil Premium 200MP, Phodia company manufactures (N₂SA:215m²/g)

Silica 6:U9000Gr, Evonik Degussa company manufactures (N₂SA:235m²/g)

Silica 7:prototype, Tokuyama Co., Ltd manufacture (N₂SA:260m²/g)

Silica 8:prototype, Tokuyama Co., Ltd manufacture (N₂SA:280m²/g)

Silane coupling agent 1:Si75, Evonik Degussa company manufactures (bis- (3- triethoxysilylpropyltetrasulfides) two Sulfide)

Silane coupling agent 2:NXT-Z45, MomentivePerformanceMaterials' manufacture

Silane coupling agent 3:NXT, MomentivePerformanceMaterials' manufacture

The manufacture of silane coupling agent 4:Si363, Evonik Degussa company

Coumarone-indene resin: NOVARES C10, Rutgers chemistry manufacture (liquid coumarone-indene resin, softening point: 5- 15℃)

Aromatic ethylene polymer: Sylvares SA85, the manufacture of Arizona chemistry be (α-methylstyrene and styrene Copolymer, softening point: 85 DEG C, Mw:1000)

Terpene phenol resin: Sylvares TP115, the manufacture of Arizona chemistry (terpene phenol resin, softening point: 115 DEG C, hydroxyl Base value: 50KOH mg/g)

TDAE:VIVATEC 500, H&R manufacture

Wax: Ozoace 0355, Japan Sekiscoat Co., Ltd.'s manufacture

Antioxidant: Antigene 6C, Sumitomo Chemical Co manufacture (N- (1,3- dimethylbutyl)-N '-phenyl P-phenylenediamine)

TMQ:NOCRAC 224, Ouchi Shinko Chemical Ind Co., Ltd.'s manufacture

Stearic acid: stearic acid " Tsubaki ", Japan Oil Co's manufacture

Zinc oxide: Ginrei R, Dong Bangxin industry Co., Ltd. manufacture

Powder sulphur containing 5% oil: HK-200-5, Hosoi chemical company manufacture

TBBS:NOCCELER NS-G, (N- tert-butyl -2-[4-morpholinodithio is sub- for Ouchi Shinko Chemical Ind Co., Ltd.'s manufacture Sulfonamide)

DPG:NOCCELER D, Ouchi Shinko Chemical Ind Co., Ltd. manufacture (diphenylguanidine)

(embodiment and reference examples)

Each formula according to shown in table 1 and 2, by rubber components, the silica of half amount, the carbon black of whole amount and one The silane coupling agent of half amount is mediated using 1.7L Banbury mixer until kneading temperature reaches 150 DEG C, with preparation kneading mixing Object 1.Next, by the kneaded mixture 1 of acquisition, the silica and silane coupling agent of surplus, sulphur removal and vulcanization accelerator Except remaining chemical reagent be added in 1.7L Banbury mixer and mediate until kneading temperature reaches 150 DEG C, pinched with preparation Close mixture 2.Then, sulphur and vulcanization accelerator are added in kneaded mixture 2 obtained, then use open roll mill It is mediated until kneading temperature reaches 105 DEG C, to prepare unvulcanized rubber composition.

Unvulcanized rubber composition obtained is placed in press cure 12 minutes at 170 DEG C and is combined with preparing vulcanized rubber Object.

Respectively, unvulcanized rubber composition obtained is shaped to the shape of tyre surface, it is on Tire production machine and other Tyre assembly fit together, be subsequently placed in 170 DEG C of press cures 12 minutes with prepare test tire.(tire size: 245/ 40R18)。

Thus obtained vulcanized rubber composition and test tire proceed as follows assessment, and test result is shown in table 1 In 2.

(viscoplasticity test)

Using the viscoplasticity spectrometer VES manufactured by Iwamoto Seisakusho Co., Ltd., vulcanized rubber is combined The complex modulus E* (MPa) and losstangenttanδ of object are measured, determination condition be 30 DEG C of temperature, 10Hz frequency, 10% Initial strain and 2% dynamic strain.E* value is bigger, and expression rigidity is higher, and then operational stability is better.Tan δ value is smaller, fever Property is lower, and then fuel economy is higher.The tan δ value also is indicated as the index relative to reference examples 1 (=100).The index is got over Height indicates that fuel economy is higher.

(wet grip performance)

Every group of test tire be all mounted on Japan manufacture preceding engine rear wheel drive (FR) automobile on (displacement: 2000cc), and the automobile travels on 10 times of test road moister than bituminous pavement.Then test drive person is to driving The control stability of period is evaluated.As a result it is expressed as the index relative to reference examples 1 (=100).The the index the high then wet Grip performance is better.

(wearability)

Every group of test tire be all mounted on Japan manufacture preceding engine rear wheel drive (FR) automobile on (displacement: 2000cc), and the automobile travels on the test road with dried asphalt road.Then the residue of tire tread rubber is measured Groove depth (initial depth: 8.0mm) is to assess wearability.Remaining groove depth is bigger, and wearability is better.Remaining groove depth be expressed as relative to The index of reference examples 1 (=100).The index is higher, and wearability is better.

(extension test)

No. 3 dumbbell shape samples are according to JIS K 6251 " vulcanized rubber or thermoplasticity as made from the vulcanized rubber composition Rubber-tensile stress-deformation nature measurement ", carries out extension test at room temperature, to measure elongation at break EB (%).EB It is better to be worth bigger expression elongation at break (durability).

[table 1]

Table 1 and 2 shows that embodiment shows outstanding wearability and good fuel economy, wet grip performance and disconnected It splits elongation (durability), embodiment has used the modification low cis BR and SBR and nitrogen for silica of predetermined content Adsorption specific surface area is 160-270m²The silica of/g.

Claims

1. a kind of rubber composition for tire tread,

On the basis of 100 mass % rubber components, the rubber composition includes: the cis-content of 10-40 mass % is 50 matter The amount % modified polybutadiene rubber and 55-75 mass % butadiene-styrene rubber below for silica, and butadiene-styrene rubber Amount is not 55 mass %；And

Relative to 100 mass parts rubber components, the N2 adsorption that the rubber composition further includes 40-120 mass parts compares table Area is 160-270m²The silica of/g,

The rubber composition further includes silane coupling agent and N2 adsorption specific surface area is 100-250m²The carbon black of/g,

It wherein, is the polybutadiene modified by following formula (1) compound represented for the modified polybutadiene rubber of silica Rubber,

Wherein R¹, R²And R³It is same or different to each other, and respectively represents alkyl, alkoxy, siloxy, acetal radical, carboxyl, Sulfydryl or their derivative；R⁴And R⁵It is same or different to each other, and respectively represents hydrogen atom or alkyl, R⁴And R⁵It can be with It is bonded to each other and is formed together ring structure together with nitrogen-atoms；And n is integer.

2. rubber composition for tire tread as described in claim 1,

Wherein, the butadiene-styrene rubber includes the modified styrene butadiene rubber for silica.

3. rubber composition for tire tread as described in claim 1,

Wherein, the silica relative to 100 mass parts, the rubber composition include 1-15 mass parts selected from by as follows At least one of the group that compound is constituted silane coupling agent:

Such as formula (I) compound represented:

Wherein, R¹⁰¹To R¹⁰³Respectively representing has branch or unbranched C1-12 alkyl, there is branch or unbranched C1-12 alcoxyl Base, or-O- (R¹¹¹-O)_z-R¹¹², wherein z R¹¹¹Respectively representing has branch or unbranched C1-30 bivalent hydrocarbon radical, z R¹¹¹ It is same or different to each other, R¹¹²Representative has branch or unbranched C1-30 alkyl, have branch or unbranched C2-30 alkenyl, C6-30 aryl or C7-30 aralkyl and z represent the integer of 1-30, R¹⁰¹To R¹⁰³It is same or different to each other；And R¹⁰⁴It represents There are branch or unbranched C1-6 alkylidene,

Wherein, R²⁰¹Hydrogen, halogen are represented, has branch or unbranched C1-30 alkyl, have branch or unbranched C2-30 alkene Base, the alkyl for thering is branch or unbranched C2-30 alkynyl or end hydrogen to be replaced by hydroxy or carboxy, R²⁰²Representative has branch or nothing The C1-30 alkylidene of branch has branch or unbranched C2-30 alkenylene or has branch or unbranched C2-30 alkynylene, R²⁰¹And R²⁰²It can be formed together ring structure, and

The compound being shown below:

4. rubber composition for tire tread as described in claim 1,

Wherein, on the basis of 100 mass % rubber components, the amount of the polybutadiene rubber synthesized using rare earth catalyst is 40 matter Measure % or less.

5. rubber composition for tire tread as described in claim 1, wherein

The rubber composition includes the liquid resin that softening point is -20~45 DEG C,

The liquid resin is at least one of liquid coumarone-indene resin and liquid terpene resin.

6. rubber composition for tire tread as described in claim 1, wherein

The rubber composition include selected from be 46~160 DEG C by softening point terpene resin, softening point be 46~140 DEG C The group that the anime that the C5 Petropols and softening point that rosin resin, softening point are 46~140 DEG C are 46~140 DEG C is constituted At least one of resin.

7. a kind of pneumatic tire is made by rubber composition such as of any of claims 1-6.

8. pneumatic tire as claimed in claim 7 is used for passenger car or sports utility vehicle.