JPH11166020A - Modified conjugated diolefin polymer, its production and rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce the subject polymer used for a rubber composition suitable for production of a tire thread excellent in abrasion resistance and wet skid resistance or the likes, and having rolling resistance by allowing the polymer to have a specific structure. SOLUTION: The polymer is obtained by allowing the polymer to have a structure of formula I [PC is a conjugated olefin polymer chain, or a copolymer chain of a conjugated diolefin and an aromatic vinyl compound; R and R' are each a 1-20C hydrocarbon or a halogen-containing hydrocarbon; Q is a monofunctional group of formulas II-IV or the like; when Q is formulas II-IV, x=1 and y=1 or 2, or x=2 and y=1; (n) and (m) are each 1-6; (a) is 2-8]. The polymer is produced by subjecting (A) the conjugated diolefin and (B) an optional aromatic vinyl compound to an anionic polymerization, reacting (C) an alkoxysilane sulfide compound of formula V [X is a monofunctional group of formulas II-IV or the like; when X is formulas II-IV, (b) is 2 or 3] with the obtained anion polymerization product.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a modified conjugated diolefin polymer which is used in a rubber composition suitable for producing a tire tread having excellent abrasion resistance, wet skid resistance and dry skid resistance and low rolling resistance. And a method for producing a modified conjugated diolefin polymer, the rubber composition and a tire tread.

[0002]

2. Description of the Related Art In recent years, there has been a demand for rubber materials for tires that reduce the rolling resistance of tires in response to demands for lower fuel consumption of automobiles. In order to reduce the rolling resistance of the tire, the energy loss of the vulcanized rubber at a low frequency may be reduced. As an evaluation index of vulcanized rubber, tan δ at 60 ° C. is used, and vulcanized rubber having a small tan δ at 60 ° C. is preferable.

[0003] Further, from the demand for running stability, a rubber material for tires having good controllability on wet and dry road surfaces, that is, high wet skid resistance and high dry skid resistance has been strongly desired. Have been. In order to improve the braking performance of a tire on a wet road surface, the energy loss of the vulcanized rubber at a high frequency may be increased. As an evaluation index of the vulcanized rubber, tan δ at 0 ° C. (tan δ 0 ° C.) is used, and a vulcanized rubber having a large tan δ 0 ° C. is preferable.
Improvement in braking performance on a dry road surface may be achieved by increasing the energy loss as in braking performance on a wet road surface. As an evaluation index of the vulcanized rubber, tan δ 30 ° C./G ′ ^0.3 30 ° C. (G ′ represents a dynamic elastic modulus) is used, and tan δ 30 ° C./G ′
Vulcanized rubber with a high ^0.3 0.30C is preferred.

However, reducing the rolling resistance and increasing the braking performance on wet and dry road surfaces are in a trade-off relationship, and it is very difficult to achieve both. Hitherto, a method has been proposed to balance these properties. For example, polymerization of a conjugated diolefin and an aromatic vinyl compound using a lithium amide initiator (JP-A-6-279515) or a rubber composition containing a styrene-butadiene copolymer having a carbon-tin bond and reinforcing silica. (JP-A-7-292162) and a solution-polymerized diene rubber composition reinforced with silica containing a low molecular weight organosilicon compound (JP-A-8-302070). However, these methods do not sufficiently satisfy the required values of the braking performance on a wet road surface, the braking performance on a dry road surface, and the rolling resistance.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a rubber composition which is simultaneously formulated to have high wet skid resistance, high dry skid resistance, low rolling resistance and abrasion resistance. It is an object of the present invention to provide a diolefin-based polymer which can provide a tire tread with improved performance. Another object of the present invention is to provide a method capable of producing the diolefin polymer. Another object of the present invention is to provide a rubber composition that provides a tire tread that simultaneously satisfies high wet skid resistance, high dry skid resistance, low rolling resistance and abrasion resistance.

[0006]

According to the present invention, there are provided the following modified conjugated diolefin polymer, a method for producing the modified conjugated diolefin polymer, a rubber composition, and a tire tread. Is achieved. [1] A modified conjugated diolefin polymer represented by the following general formula (1). _{(PC) X (RO) y} R '3- (X + y) in _{SiC n H 2n S a Q (} 1) wherein, in the formula (1), PC is conjugated diolefin polymer chain or a conjugated diolefin, R and R ′ are the same or different and represent a hydrocarbon group having 1 to 20 carbon atoms or a halogen-containing hydrocarbon group, and Q is represented by the following formula (I ), (II), (III ), or _{(IV) -C m H 2m SiR} '3- (X' + y ') (oR) y' (PC) X '(I)

[0007]

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Wherein Q is a monovalent group represented by the formula:
In the case of (I), x, x ', y, and y' are each 0 to
3, the sum of x and x 'and the sum of y and y' are each in the range of 1 to 5, and Q is in the above formulas (II) to (I
In any of V), x = 1, y = 1 or 2, or x = 2, y = 1, n is an integer of 1 to 6, and a is 2 to 8 Is an integer. [2] and the conjugated diolefin alone or the conjugated diolefin and an aromatic vinyl compound and anionic polymerization, subsequently the following general formula _{(2) R '3-b} (OR) b SiC n H 2n S a X (2) A method for producing a modified conjugated diolefin polymer, which comprises reacting an alkoxysilane sulfide compound represented by the formula (I). Here, in the general formula (2), R and R ′ are
X has the same meaning as in the case of the above general formula (1),
(V) and 1 represented by any of the above formulas (II) to (IV)
Represents a valence group, and represents -C _m H _2m Si (OR)
_{b ′} R ′ _{3-b ′} (V) (In the general formula (V), R and R ′ are the same as those in the general formula (1).) When X is the above formula (V), b and b '
Is an integer of 1 to 3, and X is the above formula (II) to (I
V) is either 2 or 3;
a is an integer from 2 to 8, and n and m are from 1 to
6 is an integer. [3] A rubber composition comprising the modified conjugated diolefin polymer according to the above [1] as a rubber component. [4] A tire tread obtained by vulcanizing and molding the rubber composition according to [3]. Hereinafter, the present invention will be described in detail,
Thereby, other objects, advantages and effects of the present invention will become apparent.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Method for producing modified conjugated diolefin polymer] For convenience of explanation, the method for producing a modified conjugated diolefin polymer of the present invention will be described first. In the production method of the present invention, the conjugated diolefin is anionically polymerized alone or the conjugated diolefin and the aromatic vinyl monomer are anionically polymerized (copolymerized). The modified conjugated diolefin polymer is produced by reacting with the alkoxysilane sulfide represented by the general formula (2). In the method of the present invention for producing a modified conjugated diolefin polymer, anionic polymerization can be used. In particular, anionic polymerization using an organic alkali metal catalyst is preferable, and most preferably anionic polymerization using an organic lithium catalyst. Hereinafter, a method for producing a modified diolefin polymer by anionic polymerization will be described in detail.

[0010] The anionic polymerization is carried out in a hydrocarbon solvent, generally an inert organic solvent. In this case, as the inert organic solvent used, for example, pentane, hexane,
Cyclohexane, heptane, benzene, xylene, toluene, tetrahydrofuran, diethyl ether and the like are used. Examples of the conjugated diolefin used for the polymerization include 1,3-butadiene and 2-methyl-1,3-
Butadiene, 2,3-dimethyl-1,3-butadiene,
Examples thereof include 2-chloro-1,3-butadiene and 1,3-pentadiene. Above all, 1,3-butadiene,
2-Methyl-1,3-butadiene and the like are preferred. The conjugated diene monomers can be used alone or in combination of two or more. As the aromatic vinyl compound, styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-diisopropylstyrene, 2,4-dimethylstyrene, 4-t-butylstyrene, Monochlorostyrene, dichlorostyrene, monofluorostyrene and the like can be mentioned. Of these, styrene is preferred. The aromatic vinyl compounds can be used alone or in combination of two or more.

When the conjugated diolefin and the aromatic vinyl compound are anionically copolymerized, the amount of the aromatic vinyl compound is not more than 1 mol, preferably not more than 0.1 mol per mol of the conjugated diolefin.
It is preferable to use 0.5 mol.

The organic alkali metal catalyst used in the polymerization is not particularly limited, but preferred organic alkali metal catalysts include n-butyl lithium, sec-butyl lithium, t-butyl lithium, 1,4-dilithium butane, Alkyl lithium such as a reaction product of butyl lithium and divinylbenzene, alkylenedilithium, phenyllithium,
Stilbene dilithium, diisopropenylbenzene dilithium, sodium naphthalene, lithium naphthalene,
Amino lithium, tin lithium and the like can be mentioned.

In the case of copolymerization, an ether compound or a tertiary amine can be used as a randomizing agent and at the same time as a regulator of the microstructure of butadiene units in the polymer, if necessary. As for example, dimethoxybenzene, tetrahydrofuran, dimexiethane, diethylene glycol dibutyl ether,
Examples thereof include diethylene glycol dimethyl ether, triethylamine, pyridine, N-methylmorpholine, N, N, N ', N'-tetramitylethylenediamine, and 1,2-dipepyridinoethane.

[0014] The polymerization method for producing a living polymer is as follows. An inert organic solvent and a monomer, ie, a conjugated diolefin alone or a conjugated diolefin and an aromatic vinyl compound, A metal catalyst and, if necessary, an ether compound or a tertiary amine are charged all at once and polymerization is carried out intermittently or continuously. The polymerization temperature is usually -120 to +15
0 ° C., preferably -80 to + 120 ° C., and the polymerization time is usually 5 minutes to 24 hours, preferably 10 minutes to 10 hours. The polymerization may be carried out at a constant temperature within the above-mentioned temperature range, or may be carried out at elevated temperature or under adiabatic conditions. Further, the polymerization reaction may be a batch type or a continuous type. The concentration of the monomer in the solvent is usually 5 to 50% by weight, preferably 10 to 35% by weight. In addition, in order to prevent the deactivation of the organic alkali metal catalyst and the living polymer for the production of the living polymer, mixing of a compound having a deactivating effect such as a halogen compound, oxygen, water or carbon dioxide gas into the polymerization system is minimized. Such considerations are necessary.

The living polymer produced by the polymerization is
Reaction with the alkoxysilane sulfide compound represented by the above formula (2). The reaction proceeds by the reaction between the anionic active terminal of the living polymer and the RO group of the specific alkoxysilane sulfide compound, whereby the polymer chain is directly bonded to the Si atom. At this time, the reaction is adjusted so that all the RO groups do not react and at least one RO group remains per one molecule of the alkoxysilane sulfide compound. The resulting modified conjugated diolefin polymer is a rubbery polymer having an Si-OR bond (where R is as defined above) and an SS bond at one end of the polymer chain.
Further, the glass transition point of the rubbery polymer is preferably -55 ° C or higher.

The alkoxysilane sulfide compound represented by the following general formula (2), which is reacted with the above living polymer, is a compound having at least one alkoxy group and an SS bond in one molecule. _{R '3-b (OR)} b SiC n H 2n S a X (2) ( where, in the general formula (2), R and R' are the same or different, a hydrocarbon group having 1 to 20 carbon atoms Or a halogen-containing hydrocarbon group, and X represents a monovalent group represented by the following formula (V) or any one of the above formulas (II) to (IV): -C _m H _2m Si (OR) _{b ′} R ′ _{3-b ′} (V) (In the general formula (V), R and R ′ have the same meanings as described above.) When X is the above formula (V), b and b ′ are each 1
When X is any of the above formulas (II) to (IV), b is 2 or 3, a is an integer of 2 to 8, and n and m are Are integers of 1 to 6, respectively. )

The OR group in the general formula (2) is an alkoxy group, an aryloxy group, a vinyloxy group, a halogenated alkoxy group or the like, preferably a methoxy group, an ethoxy group or a phenoxy group. Specific examples of preferred R 'include a methyl group, an ethyl group, an n-propyl group, a t-butyl group; a phenyl group, a toluyl group, a naphthyl group; a chloromethyl group, a bromomethyl group, an iodomethyl group, and a chloromethyl group. Can be mentioned.

Specific examples of the alkoxysilane sulfide compound represented by the general formula (2) include bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide,
Bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, 3-trimethoxysilylpropyl-N, N-
Dimethylthiocarbamoyltetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamoyltetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyltetrasulfide, 3-trimethoxysilylpropylbenzothiazole tetrasulfide , 3-triethoxysilylpropyl benzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, bis (3-diethoxymethylsilylpropyl) tetrasulfide, dimethoxymethylsilylpropyl-N, N-dimethylthiocarbamoyltetra Sulfide, dimethoxymethylsilylpropyl benzothiazole tetrasulfide and the like, and bis (3-triethoxysilylpropyl) tetrasulfide And 3-trimethoxysilylpropyl benzothiazole tetrasulfide are preferable.

The amount of the alkoxysilane sulfide compound used in the reaction between the living polymer and the alkoxysilane sulfide compound represented by the general formula (2) is preferably at least 1 molecule per 10 molecules of the living polymer, and more preferably. It is 1 to 9 molecules, particularly preferably 3 to 7 molecules. When the amount of the alkoxysilane sulfide compound used is within the above range, the obtained vulcanized rubber composition containing the modified conjugated diolefin polymer has wet skid resistance, dry skid resistance, and abrasion resistance. The improvement effect is exhibited. Note that excessive use is disadvantageous in terms of cost.

The reaction between the active terminal of the living polymer and an alkoxysilane sulfide compound having a functional group is as follows:
It is carried out by adding the compound to a solution of a polymerization system of the living polymer, or adding a solution of the living polymer to an organic solution containing the alkoxysilane sulfide compound. The addition time is not particularly limited, but, for example, the alkoxysilane sulfide compound may be divided into two portions and added to the living polymer solution. Among them, it is preferable to add the alkoxysilane sulfide compound after the polymerization is completely completed. When the alkoxysilane sulfide is added after completion of the polymerization, a small amount of butadiene may be added and the alkoxysilane sulfide may be added.

The reaction temperature of the denaturation or coupling reaction is from -120 ° C to + 150 ° C, preferably from 0 to + 120 ° C.
° C, more preferably 50 to 100 ° C, and the reaction time is 1 minute to 5 hours, preferably 5 minutes to 2 hours.

After completion of the reaction, steam is blown into the polymer solution to remove the solvent, or a poor solvent such as methanol is added to obtain a modified conjugated diolefin polymer. Further, the solvent can be directly removed from the polymer solution under reduced pressure to obtain a modified conjugated diolefin polymer. An extender oil may be added before removing the solvent and drying.

In the production method of the present invention, the molecular weight of the modified conjugated diolefin polymer can be varied over a wide range, but from the viewpoint of abrasion resistance and workability, its Mooney viscosity (ML1 + 4, 100 ° C.) 10-15
It is preferably in the range of 0.

[Modified conjugated diolefin polymer] Next, the modified conjugated diolefin polymer of the present invention will be described. According to the production method of the present invention described in detail above, the following general formula (1)
The modified conjugated diolefin polymer of the present invention represented by the following formula can be produced. _{(PC) X (RO) y} R '3- (X + y) SiC n H 2n S a Q (1) where, in the general formula (1), n is an integer from 1 to 6,
a is an integer of 2 to 8.

In the general formula (1), PC represents a conjugated diolefin homopolymer chain or a copolymer chain of a conjugated diolefin and an aromatic vinyl compound. The conjugated diolefin component constituting the homopolymer chain or the copolymer chain includes a preferred conjugated diolefin component, and the conjugated diolefin used in the above-mentioned production method can be applied as it is. Similarly, for the aromatic vinyl compound component, the preferred aromatic vinyl compound component is included, and the aromatic vinyl compound used in the above-described production method can be applied as it is.

R and R 'are the same or different and each represent a C1-20 hydrocarbon group or a halogenated hydrocarbon group. The OR group in the general formula (1) is an alkoxy group, an aryloxy group, a vinyloxy group, a halogenated alkoxy group, or the like, preferably a methoxy group,
An ethoxy group, a phenoxy group and the like. Specific examples of preferred R 'include a methyl group, an ethyl group, an n-propyl group, a t-butyl group; a phenyl group, a toluyl group, a naphthyl group; a chloromethyl group, a bromomethyl group, an iodomethyl group, and a chloromethyl group. Can be mentioned.

Q is a group represented by the following formula (I) or any one of the above formulas (II), (III) and (IV) described in the production method. —C _m H _2m SiR ′ _{3- (X ′ + y ′)} (OR) _{y ′} (PC) _{X ′} (I) (in the above formula (I), m is an integer of 1 to 6) In formula (I), x, x ', y, and y' are
Each is an integer of 0 to 3, the sum of x and x 'and y
And y ′ are in the range of 1 to 5, respectively. That is,
When Q is the above formula (I), the modified conjugated diolefin polymer of the present invention is represented by the following general formula (1 ′). _{(PC) X (RO) y} R '3- (X + y) SiC n H 2n S a C m H 2m SiR' 3- (X '+ y') (OR) y '(PC) X' (1 ')

The modified conjugated diolefin polymer represented by the above general formula (1 ′) has a PC, that is, a conjugated diolefin homopolymer chain or a copolymer chain of a conjugated diolefin and an aromatic vinyl compound, One to five Si atoms are bonded, and one to five RO groups, for example, alkoxy groups are bonded to the Si atom. Then, 2 to 8 S atoms are bonded to the Si atoms via the alkylene group. Preferably, the number of PCs (sum of x and x ') bonded to Si is 2 to 4, the number of RO groups (sum of y and y') is 2 to 4, and the number of S atoms is (A) is 2-6.

When Q is any of the above formulas (II), (III) and (IV), x = 1, y = 1 or 2
Or x = 2 and y = 1. That is, in the modified conjugated diolefin polymer in this case, one PC (a conjugated diolefin homopolymer chain or a copolymer chain of a conjugated diolefin and an aromatic vinyl compound) is bonded to one Si atom, One or two RO groups are bonded to a Si atom, or two PCs are bonded to a Si atom;
One group is bonded to the Si atom. And 2-8 S
The atom is bonded to the Si atom via an alkylene group.
Preferably, the number (x) of PCs bonded to Si is 1
Wherein the number (y) of RO groups is 2 and the number (a) of S atoms is 2 to 6.

The number of PCs and the number of RO groups bonded to Si atoms are mainly determined by the alkoxysilane sulfide represented by the general formula (2) used in the above-mentioned method for producing a modified conjugated diolefin polymer. It can be adjusted by selecting the type and amount of the compound.

The modified conjugated diolefin polymer of the present invention having the above structure has a hydrolyzable Si-OR skeleton,
In addition, since it has a crosslinkable S--S bond, an inorganic filler compounded in the rubber composition of the present invention described below in detail using the modified conjugated diolefin polymer, for example, silica and Si--O
-Form a Si bond and co-vulcanize with another rubber used in combination with the rubber composition by the action of the SS bond during vulcanization. The resulting vulcanized rubber has improved affinity due to the bonding between the rubber component and the inorganic filler, and has excellent properties such as wet skid resistance, dry skid resistance, rolling resistance, and abrasion resistance. Results.

The molecular weight of the modified conjugated diolefin polymer of the present invention is determined by the Mooney viscosity (ML1 +
4,100 ° C) is in the range of 10 to 150, especially 50 to
It is preferably in the range of 100. When the Mooney viscosity is in the above range, favorable results can be obtained in terms of wear resistance and workability.

The glass transition point (glass transition temperature) of the modified conjugated diolefin polymer of the present invention is -55 ° C. or higher, particularly -5, from the viewpoint of wet skid resistance of the tire.
It is preferably 0 to -20 ° C.

Specific examples of the preferred modified conjugated diolefin polymer of the present invention include the following. _{(PC) (H 5 C 2} O) 2 Si-C 3 H 6 -Si (OC 2 H 5) (P
C) Here, PC is a copolymer chain of an aromatic vinyl compound and a conjugated diolefin.

[Rubber Composition] Next, the rubber composition of the present invention will be described. The rubber composition of the present invention is characterized by containing the modified conjugated diolefin polymer. And as a preferable rubber composition, the following components (a) to
Those containing (f) can be mentioned. (A) 10 to 100 parts by weight, preferably 30 to 100 parts by weight of the modified conjugated diolefin polymer, (b) the (a)
90 to 0 parts by weight of rubber other than the modified conjugated diolefin polymer, preferably 70 to 0 parts by weight (where the total amount of the components (a) and (b) is 100 parts by weight);
(C) carbon black and / or silica 40-1
20 parts by weight, preferably 50 to 100 parts by weight, (d) 0 to 80 parts by weight of process oil, preferably 10 to 40 parts by weight, (e) 0 to 20 parts by weight of silane coupling agent, preferably 0 to 10 parts by weight And (f) a rubber composition comprising an effective amount of a vulcanizing agent.

As the rubber component (b), natural rubber; polybutadiene rubber such as high cis polybutadiene rubber and low cis polybutadiene rubber obtained by using nickel, cobalt, titanium and neodymium catalyst; styrene-butadiene copolymer rubber by emulsion polymerization Styrene unit is 10-4
Styrene-butadiene copolymer rubber such as solution-polymerized styrene-butadiene copolymer rubber having 5% by weight and a 1,2-vinyl bond unit content of 15 to 90% by weight of butadiene units; isoprene rubber; ethylene-propylene -Diene terpolymer rubber and the like. These can be used alone or in combination of two or more.

The carbon black as the component (c) is commercially available SRF, GPF, FEF, MAF, HA
F, ISAF, SAF, etc. can be used, and among them, use of HAF, ISAF, SAF is preferable. Silica is also commercially available Nipsil VN3, Nipsil AQ,
Carplex # 80, Toksil V, Toksil VR
And the like, among which Nipseal VN3,
The use of Nipseal AQ is preferred. Carbon black and silica can be used alone, but preferably both are used in combination.

As the process oil which is the component (d),
Either an aromatic process oil or a naphthene process oil can be used. These are commercially available, for example, Fukkor AROMAX # 1, # 3, #
5, Resox No.1, No.3, JSR AROM
A, Diana process oil NS-100, NV-2
0 and the like. Above all, Fukkor A
It is preferable to use ROMAX # 1, # 3, # 5, or AROMA manufactured by JSR.

Examples of the silane coupling agent (e) include bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, and 3-trimethoxysilylpropylbenzothiazoletetrasulfide. And 3-mercaptopropyltrimethoxysilane. Of these, use of bis (3-triethoxysilylpropyl) tetrasulfide and 3-trimethoxysilylpropylbenzothiazole tetrasulfide is preferred. By using a silane coupling agent, it is possible to improve the affinity between the rubber component and the component (d), and further, if necessary, the filler and the filler.

(F) Examples of the vulcanizing agent include precipitated sulfur, insoluble sulfur, sulfur chloride, sulfur-free vulcanizing agents, peroxide vulcanizing agents, etc. Among them, use of precipitated sulfur, peroxide vulcanizing agents Is preferred.

The rubber composition of the present invention can further contain various compounding agents, vulcanization accelerators and the like, and can be appropriately selected from various compounding agents widely used in the rubber industry according to the purpose and application. it can. The rubber composition of the present invention can be obtained by kneading the above components using a kneading device such as a kneader, a Banbury mixer, a plast mill, or a roll. From the rubber composition of the present invention, not only the tire tread, but also rubber parts other than the tire tread constituting the tire, and other industrial articles such as a vibration-proof rubber, a belt, and a hose can be manufactured.

[Production of Tire Tread] In order to form a tire tread of a tire from the rubber composition of the present invention,
It can be formed using a method known per se. For example, molding the rubber composition of the present invention into a tread shape,
After being bonded to another tire portion, the tire tread integrated with the tire can be formed by heating and vulcanizing. The tire tread of the present invention is excellent in high wet skid resistance, high dry skid resistance, low rolling resistance and abrasion resistance.

[0043]

EXAMPLES The present invention will now be described in detail with reference to examples, but the scope of the present invention is not limited to the examples.
Various measurements in the examples were based on the following methods. (1) Mooney viscosity: Measured at 100 ° C. for 1 minute with a rotor operating time of 4 minutes according to JIS K6300. (2) Microstructure of copolymer: determined by infrared absorption spectroscopy (Morello method). (3) Styrene unit content: Determined by creating a calibration curve by infrared absorption spectroscopy.

(4) Evaluation of physical properties of vulcanized material: Using a vulcanized material obtained by kneading and compounding with a 250 cc Labo Plastomill according to the compounding recipe shown in Table 3 below and then press-curing at 150 ° C. for 40 minutes. The following various measurements were performed. Lambourn abrasion index: It was expressed by abrasion amount at a slip ratio of 60% using a Lambourn abrasion tester. The measurement temperature was room temperature. The larger the index, the better the wear resistance. tan δ60 ° C .: Measured under the conditions of a tensile strain of 1%, a frequency of 10 Hz and a temperature of 60 ° C. using a dynamic spectrometer manufactured by Rheometrics, USA. Using the value of Comparative Example 8 as a standard (100), it was indicated by an index. The higher the value, the lower the rolling resistance and the better. tan δ 30 ° C./G ′ ^0.3 30 ° C .: Using the above dynamic spectrometer, tensile strain 1%, frequency 10H
The measurement was performed under the conditions of z and 30 ° C. The value of Comparative Example 8 was standard (1
00) as an index. The higher the value, the greater the dry skid resistance and the better. tan δ0 ° C .: Measured using the above dynamic spectrometer under the conditions of a tensile strain of 0.1%, a frequency of 10 Hz, and 0 ° C. Using the value of Comparative Example 8 as a standard (100), it was indicated by an index. The higher the value, the greater the wet skid resistance and the better.

<Production of Modified Conjugated Diolefin Polymer> (Example 1) As shown in Table 2, cyclohexane 3000 was placed in a nitrogen-purged reaction vessel having an internal volume of 5 liters.
g, styrene 192 g, 1,3-butadiene 320 g,
21.2 g of tetrahydrofuran was charged. After adjusting the polymerization initiation temperature to 35 ° C, 3.8 m of n-butyllithium was used.
mol was added to perform polymerization. When the polymerization conversion reached 100%, 38 g of 1,3-butadiene was added,
After changing the polymer chain end to butadienyl lithium, 1.14 mmol of a modifier bis (3-triethoxysilylpropyl) tetrasulfide was added, and the mixture was reacted for 10 minutes.
2,6-Di-tert-butyl-p-cresol was added to the polymer solution, and an aromatic extender oil (AROM manufactured by Nippon Synthetic Rubber Co., Ltd.) was added to 100 parts by weight of the copolymer.
A) was added by 37.5 parts by weight, the solvent was removed by steam stripping, and dried with a hot roll at 110 ° C. to synthesize a modified conjugated diolefin polymer (modified polymer No. 1). Modified polymer No. Gel Permeation Chromatography (GPC) No. 1 (Waters, 224
In the (type) chart, peaks were observed at molecular weights of 250,000 and 620,000, and it was confirmed that a modified conjugated diolefin polymer having the following structure A or B was formed from each peak. A: A structure in which one ethoxy group of the modifier is substituted with a copolymer chain B: Two ethoxy groups and three ethoxy groups of the modifier are
Structures each substituted with a copolymer chain

Example 2 In Example 1, the screw (3
-Triethoxysilylpropyl) tetrasulfide was carried out in the same manner as in Example 1 except that the amount of addition was 1.66 mmol, and a modified conjugated diolefin polymer (modified polymer N
o. 2) was synthesized. Modified polymer No. In the GPC chart of No. 2, peaks were observed at molecular weights of 250,000 and 490,000, and it was confirmed from each peak that a modified conjugated diolefin polymer having the following structures A ′ and B ′ was formed. . A ': A structure in which one ethoxy group of the modifying agent is substituted with a copolymer chain B': A structure in which two ethoxy groups of the modifying agent are substituted by a copolymer chain

Example 3 In Example 2, the screw (3
-Triethoxysilylpropyl) tetrasulfide to 3
-Modified conjugated diolefin polymer (modified polymer No. 2) except that trimethoxysilylpropylbenzothiazole tetrasulfide was used.
3) was synthesized. Modified polymer No. In the GPC chart of No. 3, peaks were observed at positions of 260,000 and 480,000 in molecular weight, and it was confirmed that a modified conjugated diolefin polymer having the following structure D or E was formed from each peak. D: Structure in which one ethoxy group of the modifying agent is substituted by a copolymer chain E: Structure in which two ethoxy groups of the modifying agent are substituted by a copolymer chain

Example 4 A modified conjugated diolefin polymer (modified polymer No. 1) was prepared in the same manner as in Example 1 except that the amount of styrene was changed to 165 g.
4) was synthesized. Modified polymer No. In the GPC chart of No. 4, peaks were observed at molecular weights of 240,000 and 680,000, and it was confirmed from each peak that a modified conjugated diolefin polymer having the following structure of F or G was formed. F: Structure in which one ethoxy group of the modifier is substituted with a copolymer chain G: Two ethoxy groups and three ethoxy groups of the modifier are
Structures each substituted with a copolymer chain

Comparative Example 1 In Example 1, the screw (3
-Triethoxysilylpropyl) tetrasulfide was replaced with silicon tetrachloride in the same manner as in Example 1 to obtain a modified conjugated diolefin polymer (Modified Polymer No. 1).
5: comparison).

Table 1 shows the main polymerization conditions of Examples 1 to 4 and Comparative Example 1, and the composition and physical properties of the modified conjugated diolefin polymer obtained.

[0051]

[Table 1]

<Performance of Rubber Composition> Table 2 shows the composition used for the evaluation, and Table 3 shows the type of the modified conjugated diolefin polymer and the results of the evaluation of the vulcanization properties.

[0053]

[Table 2]

[0054]

[Table 3]

The following is clear from these results. That is, the vulcanized product of the rubber composition using the modified conjugated diolefin polymer of the present invention synthesized in Examples 1 to 4 has wet skid resistance, dry skid resistance, low rolling resistance, and abrasion resistance. Excellent in properties. On the other hand, the vulcanizate of the rubber composition using the modified conjugated diolefin polymer synthesized in Comparative Example 1 using silicon tetrachloride as the modifier has wet-skid resistance, dry-skid resistance, and low rolling resistance. Inferior in vulcanization properties, and wear resistance
(Comparison between Examples 5 to 8 and Comparative Example 2, and comparison between Example 9 and Comparative Example 3).

[0056]

The vulcanizate of the rubber composition containing the modified conjugated diolefin polymer of the present invention is excellent in wet skid resistance, dry skid resistance, low rolling resistance and abrasion resistance, and has a tire tread. Satisfies the required physical properties. Therefore, an excellent tire tread is manufactured from the rubber composition. Further, the method for producing a modified conjugated diolefin polymer of the present invention is suitable as a method for producing the modified conjugated diolefin polymer of the present invention.

The preferred embodiments of the present invention will be described below. (1) The glass transition point of the modified conjugated diolefin polymer represented by the general formula (1) is −55 ° C. or higher, particularly −50 to
-20 ° C. (2) Mooney viscosity of the modified conjugated diolefin polymer
(ML1 + 4, 100 ° C.) is in the range of 10 to 150. (3) The conjugated diolefin unit constituting PC of the general formula (1) is 1,3-butadiene and / or 2-methyl-
It must be 1,3-butadiene units. (4) The aromatic compound unit constituting PC of the general formula (1) is a styrene unit. (5) The compound represented by the general formula (2) to be reacted with the living polymer is bis (3-triethoxysilylpropyl) tetrasulfide and / or 3-trimethoxysilylpropylbenzothiazole tetrasulfide. (6) General formula (2) per 10 molecules of living polymer
At least one molecule, more preferably 1 to 9
Molecule, more preferably 3 to 9 molecules. (7) The rubber composition comprises (a) 10 to 100 parts by weight of the modified conjugated diolefin polymer, more preferably 30 to 10 parts by weight.
0 parts by weight, (b) 90 to 0 parts by weight of rubber other than the (a) modified conjugated diolefin polymer, more preferably 70 to 0 parts by weight (here, the total of the components (a) and (b) (The amount is 100 parts by weight), (c) 40 to 120 parts by weight of carbon black and / or silica, more preferably 50 to 100 parts by weight, and (d) process oil 0 to 80 parts by weight.
Parts by weight, more preferably 10 to 40 parts by weight, (e) 0 to 20 parts by weight of the silane coupling agent, more preferably 0 to
10 parts by weight, and (f) an effective amount of a vulcanizing agent.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Fumio Tsutsumi, Inventor Nippon Gosei Rubber Co., Ltd. 2-1-1-24 Tsukiji, Chuo-ku, Tokyo

Claims (4)

[Claims] 1. A modified conjugated diolefin polymer represented by the following general formula (1). _{(PC) X (RO) y} R '3- (X + y) SiC n H 2n S a Q (1) where, in the formula (1), PC is a conjugated diolefin polymer chain or a conjugated diolefin Represents a copolymer chain with an aromatic vinyl compound, wherein R and R ′ are the same or different and have 1 to 20 carbon atoms
Represents a hydrocarbon group or halogen-containing hydrocarbon group, Q is the following formula (I), (II), (III), or _{(IV) -C m H 2m SiR} '3- (X' + y ') (OR) _{y '} (PC) _X' (I) And when Q is the above formula (I), x, x ′, y and y ′ are each an integer of 0 to 3, and the sum of x and x ′ and y And y ′ are in the range of 1 to 5, respectively. When Q is any of the above formulas (II) to (IV), x = 1,
y = 1 or 2, or x = 2, y = 1, n and m are each an integer from 1 to 6, and a
Is an integer of 2 to 8. 2. An anion polymerization of a conjugated diolefin alone or a conjugated diolefin and an aromatic vinyl compound,
Continuing production of the following general formula _{(2) R '3-b} (OR) b SiC n H 2n S a X (2) , characterized in that the reaction of alkoxysilane sulfide compounds represented by the modified conjugated diolefin polymer Method. Here, in the general formula (2), R and R ′ have the same meanings as in the general formula (1), and X is any one of the following formula (V) and any of the above formulas (II) to (IV) in represents a monovalent group _{represented, -C m H 2m Si (oR} ) b 'R' 3-b '(V) ( in formula (V), R and R', the general formula (1)
When X is the above formula (V), b and b ′ are each an integer of 1 to 3, and when X is any of the above formulas (II) to (IV) Is b is 2 or 3, a is an integer from 2 to 8, and n and m are each an integer from 1 to 6. 3. A rubber composition comprising the modified conjugated diolefin polymer according to claim 1 as a rubber component. 4. A tire tread obtained by vulcanizing and molding the rubber composition according to claim 3.