JP4687545B2 - Modified conjugated diene polymer rubber and rubber composition containing the same - Google Patents

Description

  The present invention relates to a modified conjugated diene polymer rubber and a rubber composition containing the same, and more particularly, a modified conjugated diene polymer rubber having improved processability, low heat build-up and wear resistance, and a rubber composition containing the same. About.

  In recent years, as a rubber material for tires, a method using a rubber composition in which silica or a mixture of silica and carbon black is mixed with a reinforcing filler is generally used. A tire tread using a rubber composition containing silica has low rolling resistance and good steering stability as typified by wet skid resistance, but has a problem of inferior tensile strength and wear resistance. In order to solve this problem, a conjugated diene polymer in which a functional group having an affinity for silica is introduced has been proposed. For example, Patent Document 1 discloses a conjugated diolefin copolymer rubber excellent in workability by binding a primary amino group and an alkoxysilyl group to a copolymer chain and excellent in grip performance, wear resistance, and low rolling resistance. Proposed to provide.

JP 2004-168904 A

  Accordingly, an object of the present invention is to provide a modified conjugated diene polymer suitable for blending into a rubber composition having good processability, good low heat build-up, and excellent wear resistance, and blending it, for example, pneumatic It is providing the rubber composition used for a tire etc.

  According to the present invention, a conjugated diene monomer, or a polymer or copolymer obtained by polymerizing a conjugated diene monomer and an aromatic vinyl compound using an organic active metal catalyst, at the polymerization active terminal, There is provided a modified conjugated diene polymer rubber obtained by reacting an oxazolidinesilane compound having at least one oxazolidine group and at least two alkoxysilyl groups in the molecule.

（式中、Ａ¹〜Ａ³は、それぞれ独立に、アルコキシル基、アルキル基、アリール基及び水素のいずれか一つであり、Ａ⁴及びＡ⁵は、それぞれ独立に、Ｓｉ，Ｏ，Ｎ，Ｓを含んでいても良い有機基、Ｒ¹はＮ，Ｏ，Ｓ，Ｐを含んでいても良い直鎖、脂環又は芳香環を含む炭素数１〜３０の炭化水素基であり、Ｒ²〜Ｒ⁴は、それぞれ独立に、炭素数１〜２０のアルキル基又は炭素数６〜１８のアリール基又は水素であり、ｍは０〜２０の整数であり、ｎは１〜２０の整数である）
で示される前記変性共役ジエン系重合体ゴムが提供される。 According to the invention, the oxazolidinesilane compound is further of the formula (I) or (I ′):

(In the formula, A ^{1 to} A ³ are each independently any one of an alkoxyl group, an alkyl group, an aryl group, and hydrogen, and A ⁴ and A ⁵ are each independently Si, O, N, organic group which may contain S, R ¹ is N, O, S, good linear also contain P, hydrocarbon group having 1 to 30 carbon atoms containing an alicyclic or aromatic ring, R ² to R ⁴ are each independently an aryl group or hydrogen 6-18 alkyl group carbon atoms or 1 to 20 carbon atoms, m is an integer of 0 to 20, n is a an integer from 1 to 20 )
The modified conjugated diene polymer rubber represented by the formula:

  According to the present invention, a conjugated diene monomer, or a polymerization active terminal of a polymer or copolymer obtained by polymerizing a conjugated diene monomer and an aromatic vinyl compound using an organic active metal catalyst, Rubber composition having good processability, good low heat build-up, and excellent wear resistance by reacting an oxazolidinesilane compound having at least one oxazolidine group and at least two alkoxysilyl groups in the molecule Can be obtained.

  As a result of advancing research to solve the above-mentioned problems, the present inventors obtained a conjugated diene monomer, or a conjugated diene monomer and an aromatic vinyl compound by polymerization using an organic active metal catalyst. A rubber composition in which a modified conjugated diene polymer rubber and silica obtained by reacting an oxazolidinesilane compound with a polymerization active terminal of a polymer or a copolymer exhibits good processability and low heat build-up It has been found that it exhibits good viscoelastic properties that correlate with, and excellent wear resistance.

  Examples of the conjugated diene monomer constituting the skeleton of the modified conjugated diene polymer of the present invention include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1, and the like. Examples of the aromatic vinyl monomer include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, 2,4, and the like. -Dimethylstyrene, 2,4-diisopropylstyrene, 4-tert-butylstyrene, divinylbenzene, tert-butoxystyrene, vinylbenzyldimethylamine, (4-vinylbenzyl) dimethylaminoethyl ether, N, N-dimethylaminoethylstyrene Vinyl pyridine and the like.

  As the organic active metal catalyst used in the present invention, an organic alkali metal compound is preferably used. For example, organic monometallic compounds such as n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, phenyllithium and stilbenelithium are used. Lithium compounds; organic polyvalent lithium compounds such as dilithiomethane, 1,4-dilithiobutane, 1,4-dilithio-2-ethylcyclohexane, 1,3,5-trilithiobenzene; organic sodium compounds such as sodium naphthalene; potassium naphthalene, etc. Of the organic potassium compound. In addition, 3,3- (N, N-dimethylamino) -1-propyllithium, 3- (N, N-diethylamino) -1-propyllithium, 3- (N, N-dipropylamino) -1- Propyllithium, 3-morpholino-1-propyllithium, 3-imidazole-1-propyllithium and organolithium compounds in which these are chain-extended with 1 to 10 units of butadiene, isoprene or styrene can also be used.

  The oxazolidinesilane compound having at least one oxazolidine group and at least two alkoxysilyl groups in the molecule used in the present invention is, for example, a method of reacting an alkoxysilane compound having an epoxy group with ketimine or aldimine, It can be synthesized by a method of reacting an alkoxysilane compound having ketimine or aldimine.

Preferable oxazolidinesilane compounds include compounds represented by the above formula (I) or (I ′). In formula (I) or (I ′), A ^{1 to} A ³ are each independently any one of an alkoxyl group, an alkyl group, an aryl group, and hydrogen, preferably an alkoxyl group having 1 to 18 carbon atoms, An alkyl group having 1 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, and hydrogen, and A ⁴ and A ⁵ are each independently an organic group or a hydroxyl group that may contain Si, O, N, and S. , Preferably methoxy, ethoxy, propoxy, butoxy, phenoxy, methyl, ethyl, butyl, propyl, phenyl, hydrogen, hydroxyl, trimethylsilyl, triethylsilyl, R ¹ Is a C1-C30 hydrocarbon group containing a straight chain, an alicyclic ring or an aromatic ring which may contain N, O, S, P, and preferably a methylene group, an ethylene group, a propylene group, a phenyl group. Ren group, toluylene group, and these imino bond, an ether bond, a thioether bond, an atomic group formed by bonding through a phosphine (group), R ² to R ⁴ are each independently, having 1 to 20 carbon atoms Or an aryl group having 6 to 18 carbon atoms, preferably methyl, ethyl, propyl, isopropyl, butyl, isobutyl, benzyl, isopentyl, phenyl, toluyl, naphthyl or hydrogen. Yes, m is an integer of 0 to 20, preferably an integer of 0 to 10, and n is an integer of 1 to 20, preferably an integer of 1 to 10.

  Another preferred example of the oxazolidinesilane compound is the formula (II) or (II ′):

It is a compound represented by these. In the formula (II) or (II ′), R ¹ is a hydrocarbon group having 1 to 30 carbon atoms including a straight chain, alicyclic ring or aromatic ring which may contain N, O, S, P, preferably Is a methylene group, ethylene group, propylene group, phenylene group, toluylene group, or an atomic group (group) formed by bonding these via an imino bond, an ether bond, a thioether bond or a phosphine, and R ^{2 to} R ⁴ are each independently an alkyl group having 1 to 20 carbon atoms, preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, an isopentyl group, or an aryl group having 6 to 18 carbon atoms. is preferably a phenyl group, a toluyl group, a naphthyl group or hydrogen, R ⁵ to R ⁷ are each independently an alkyl group having 1 to 20 carbon atoms, preferably a methyl group, an ethyl group, a propyl , An isopropyl group, a butyl group, an isobutyl group, a pentyl group, an isopentyl group, or an aryl group having 6 to 18 carbon atoms, preferably a phenyl group, a toluyl group, or a naphthyl group, and n is an integer of 1 to 20, preferably 1 to 10. It is.

  When at least a part of the modified conjugated diene polymer rubber according to the present invention reacts with moisture, the oxazolidine group is hydrolyzed to produce an amino group and a hydroxyl group, so that the affinity with the filler is expected to increase. The

  In combination with the oxazolidinesilane compound used in the present invention, tin compound, silicon compound, amide compound and / or imide compound, isocyanate and / or isothiocyanate compound, ketone compound, ester compound, vinyl compound, oxirane compound, thiirane compound Polysulfide compounds, halogen compounds, and fullerenes may be added as modifiers or coupling agents.

  The rubber composition according to the present invention preferably contains the modified conjugated diene polymer rubber in an amount of 1 to 100% by weight, more preferably 10 to 100% by weight, based on the total amount of the rubber component. If the amount of the modified conjugated diene polymer rubber is too small, it may be difficult to achieve the object of the present invention.

  The other rubber component that can be blended in the rubber composition of the present invention can be any rubber that can be used for a pneumatic tire. Specific examples include, but are not limited to, natural rubber (NR), polyisoprene rubber (IR), styrene-butadiene copolymer rubber, various polybutadiene rubbers (BR), and acrylonitrile-butadiene copolymer. Examples thereof include polymer rubber, butyl rubber, halogenated butyl rubber, ethylene-propylene-diene copolymer rubber, ethylene-propylene copolymer rubber, and chloroprene rubber.

  In the rubber composition according to the present invention, 5 to 120 parts by weight, preferably 10 to 100 parts by weight of a reinforcing filler is blended with 100 parts by weight of the rubber component containing the modified conjugated diene polymer rubber. If the blending amount of the reinforcing agent is small, the desired reinforcing effect cannot be obtained. Conversely, if the blending amount is large, the workability deteriorates and the heat generation increases, which is not preferable. As the reinforcing filler, a part or all of it is silica and / or a reinforcing filler in which at least a part of the surface thereof is formed of silica (for example, silica surface-coated carbon as described in JP-A-8-277347). Black) is preferably used. As the silica, normal dry silica or wet silica can be used.

  In addition to the essential components described above, the rubber composition according to the present invention includes a vulcanization or cross-linking agent, a vulcanization or cross-linking accelerator, various oils, an anti-aging agent, a plasticizer and the like, and other rubber compositions. Various additives generally blended for use can be blended, and such additives can be kneaded by a general method to form a composition, which can be used for vulcanization or crosslinking. As long as the amount of these additives is not contrary to the object of the present invention, a conventional general amount can be used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, it cannot be overemphasized that the scope of the present invention is not limited to these Examples.

The raw materials used in the following examples are as follows.
Cyclohexane, styrene: those manufactured by Kanto Chemical Co., Ltd. were dehydrated with molecular sieves 4A and used after bubbling with nitrogen.
Butadiene: Butadiene (purity 99.3% product) manufactured by Nippon Petrochemical Co., Ltd. was used after dehydration with Molecular Sieves 4A.
n-Butyllithium: An n-hexane solution (1.57 mol / L) manufactured by Kanto Chemical Co., Inc. was used.
1,1,4,4-tetramethylethylenediamine (TMEDA): A product manufactured by Kanto Chemical Co., Ltd. was dehydrated with molecular sieves 4A and used after bubbling with nitrogen.
Tetramethoxymethoxysilane: Shin-Etsu Chemical Co., Ltd. was used as it was.
3- (2-Isopropyl-5-methyloxazolidino) propyltriethoxysilane (Compound I): Shin-Etsu Chemical Co., Ltd. product was used as it was.

Example 1 (Production of polymer A)
An autoclave reactor with a nitrogen content of 10 L was charged with 4563 g of cyclohexane, 165.6 g (1.590 mol) of styrene, 634.4 g (11.73 mol) of butadiene, and 1.060 mL (7.196 mmol) of TMEDA, and stirring was started. did. After the temperature of the contents in the reaction vessel was 50 ° C., 3.883 mL (6.097 mmol) of n-butyllithium solution was added. After the polymerization conversion rate reached 100%, 1.358 g (4.071 mmol) of Compound I was added and stirred for 1 hour. Further, 0.5 mL of methanol was added and stirred for 30 minutes. A small amount of an antioxidant (Irganox 1520) was added to the resulting polymer solution, and the solvent was removed by concentration under reduced pressure. The polymer was coagulated and washed in methanol, and then dried to obtain a solid polymer.

Example 2 (Production of polymer B)
80 mL of water was added to 2100 g of the polymer solution taken out in the production of the polymer A, and the mixture was stirred at 85 ° C. for 7 hours. A small amount of an antioxidant (Irganox 1520) was added to the resulting polymer solution, and the solvent was removed by concentration under reduced pressure. The polymer was coagulated and washed in methanol, and then dried to obtain a solid polymer.

Comparative Example 1 (Production of polymer C)
A nitrogen-substituted autoclave reactor with a volume of 10 L was charged with 3137 g of cyclohexane, 113.8 g (1.093 mol) of styrene, 438.9 g (8.172 mol) of butadiene, and 0.812 mL (5.535 mmol) of TMEDA, and stirring was started. did. After the temperature of the contents in the reaction vessel was 50 ° C., 3.330 mL (5.266 mmol) of n-butyllithium solution was added. After the polymerization conversion reached 100%, 0.210 g (1.383 mmol) of tetramethoxysilane was added and stirred for 1 hour. Subsequently, 0.5 mL of methanol was added and stirred for 1 hour. A small amount of an anti-aging agent (Irganox 1520) was added to the removed polymer solution, and the solvent was removed by concentration under reduced pressure. The polymer was coagulated and washed in methanol, and then dried to obtain a solid polymer.

Comparative Example 2 (Production of polymer D)
A nitrogen-substituted autoclave reactor with a volume of 10 L was charged with 3138 g of cyclohexane, 115.6 g (1.110 mol) of styrene, 438.9 g (8.172 mol) of butadiene, and 0.814 mL (5.464 mmol) of TMEDA, and stirring was started. did. After the temperature of the contents in the reaction vessel was 50 ° C., 3.805 mL (5.936 mmol) of n-butyllithium solution was added. After the polymerization conversion rate reached 100%, 0.5 mL of methanol was added and stirred for 30 minutes. A small amount of an anti-aging agent (Irganox 1520) was added to the removed polymer solution, and the solvent was removed by concentration under reduced pressure. The polymer was coagulated and washed in methanol, and then dried to obtain a solid polymer.

Comparative Example 3 (Production of polymer E)
A polymer as shown in Table I was obtained in the same manner as in the case of the polymer C except that the amount of n-butyllithium added was halved.

In the mixing (parts by weight) shown in Table II, the components other than the vulcanization accelerator and sulfur were kneaded with a 0.6 liter closed mixer for 5 minutes. The obtained master batch, vulcanization accelerator, and sulfur were kneaded with an 8-inch open roll to obtain a rubber composition. This composition was press vulcanized at 160 ° C. for 30 minutes in a 15 × 15 × 0.2 cm mold and a disk-shaped lambone test sample mold having a diameter of 63.5 mm and a thickness of 5 mm to obtain a vulcanized rubber sample. Obtained. The physical properties of the obtained rubber composition and vulcanized rubber sample were tested by the following methods, and the results are shown in Table II.

Test method Mooney viscosity (ML _{1 + 4} (100 ° C.)): Measured according to JIS K-6300. The lower the Mooney viscosity, the better the processability.

  Viscoelasticity (tan δ): Using a viscoelastic spectrometer manufactured by Toyo Seiki Seisakusho, the initial strain was 10%, the amplitude was ± 2%, and the frequency was 20 Hz at 60 ° C. The smaller this value, the lower the heat generation.

Abrasion resistance: Measured in accordance with JIS K6264 using a Lambourn abrasion tester under the conditions of a load of 15 N and a slip ratio of 50%. When the amount of wear in Comparative Example 7 is 100, the formula:
(Abrasion amount of Comparative Example 7) × 100 / (Abrasion amount of sample)
It was calculated by the index. A larger index value indicates better wear resistance.

Table II footnotes 1) to 5) See Examples 1 and 2 and Comparative Examples 1 to 3 respectively 6) SBR (Nipol NS116) manufactured by Nippon Zeon Co., Ltd.
7) UNITED SILICA INDUSTRIAL LTD. Silica (ULTRASIL 7000GR)
8) Carbon black (show black N339) manufactured by Cabot Japan
9) Rhein Chemie Ltd. Fatty acid zinc (containing inorganic carrier) (actiplast ST)
10) Zinc Hana No. 3 manufactured by Shodo Chemical Co., Ltd. 11) Bead stearic acid paulownia manufactured by Nippon Oil & Fats Co., Ltd. 12) Santoflex 13,6C manufactured by Nippon Monsanto Co., Ltd.
13) Sigus (bis- (3-triethoxysilyl-propyl) tetrasulfide) manufactured by Degussa
14) Aroma oil (Extract No. 4 S) manufactured by Showa Shell Co., Ltd.
15) Ouchi Shinsei Chemical Co., Ltd. vulcanization accelerator (Noxeller CZ-G)
16) Vulcanization accelerator (Soccinol DG) manufactured by Sumitomo Chemical Co., Ltd.
17) Sulfur manufactured by Tsurumi Chemical Co., Ltd. In Comparative Example 6, a polymer having the same molecular weight as that of the coupling body and a polymer having the same molecular weight as that of the original polymer are blended so that the molecular weight distribution of the polymer is equivalent to that of the other examples. It was adjusted.

  As described above, according to the present invention, a modified conjugated diene system obtained by reacting an oxazolidinesilane compound with a polymerization active terminal obtained by polymerizing a conjugated diene monomer or an aromatic vinyl compound with an organic active metal catalyst. By blending a polymer rubber, a rubber composition excellent in processability, low heat build-up, breaking strength and wear resistance can be obtained. For example, tread, under tread, carcass, sidewall, bead portion of a pneumatic tire. Useful as such.

Claims (4)

A conjugated diene monomer, or a polymer or copolymer obtained by polymerizing a conjugated diene monomer and an aromatic vinyl compound using an organic active metal catalyst, has 3- (2-isopropyl) A modified conjugated diene polymer rubber obtained by reacting -5-methyloxazolidino) propyltriethoxysilane . A modified conjugated diene polymer rubber obtained by reacting at least part of the modified conjugated diene polymer rubber according to claim 1 with moisture. Comprise 100 parts by weight of the rubber component and silica and / or reinforcing filler 5-120 parts by weight of at least partially formed by the silica of the surface containing the modified conjugated diene polymer rubber according to claim 1 or 2 A rubber composition comprising: A pneumatic tire using the rubber composition according to claim 3 .