JPH0649800B2 - Butadiene polymer rubber composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a butadiene-based polymer rubber composition, and more specifically to a branched butadiene-based polymer having a branched structure of 3 or more branches in its molecular chain ( The present invention relates to a butadiene-based polymer rubber composition containing A) and a linear butadiene-based polymer modified with a specific functional group in its molecular chain.

[Conventional technology]

Conventionally, in a butadiene-based polymer such as a butadiene homopolymer or a copolymer of butadiene and styrene,
Those containing a metal-carbon bond in the molecular chain or those containing a conventional coupling agent have been proposed. They are,
The main focus was on improving the cold flow properties of the resulting polymers.

Generally, a polymer having a branched structure of this kind has a shorter chain length than a linear polymer having the same molecular weight.

For example, considering a trifunctional branched polymer as the branched polymer, when compared with a linear polymer at the same molecular weight,
The length of the extended chain is 2/3. Therefore, the branched polymer is excellent in processability, but on the other hand, the number of molecular terminals not involved in vulcanization is large and heat generation (hysteresis loss) becomes large. However, it was found that the polymer having a branched structure having a tin-butadienyl bond generated less heat than expected.

And, in recent years, in order to reduce rolling frictional resistance, increase wet skid resistance, and improve fracture characteristics from the demand for low fuel consumption of automobiles, butadiene having a high vinyl bond branched with a metal-carbon bond in the molecular chain is used. A polymer has been proposed (for example, JP-A-57-55912).

[Problems to be solved by the invention]

However, in response to the recent high demands from the rubber industry, there is an increasing demand for arbitrary control of hysteresis loss, and conventional butadiene-based polymers have a large strain dependency of hysteresis loss (Pain effect), and the performance is sufficiently high. I am not satisfied.

As a result of earnest studies on a butadiene-based polymer having a branched structure, the present inventors have found that a branched butadiene-based polymer having a branched structure of three or more branches in the molecular chain and a functional functional group at the terminal of the molecular chain. By containing a linear butadiene-based polymer having a group, not only can a polymer rubber composition that can control heat generation, have excellent breaking properties, and have an excellent Pain effect, It was found that the processability and vulcanization rate during blending with other diene rubbers were significantly improved, and the vulcanized physical properties were also excellent,
The present invention has been reached.

[Means for solving problems]

That is, the present invention provides, as a rubber component, at least 15% by weight of a branched butadiene-based polymer (A) polymerized by using an organolithium compound as an initiator, and the following groups (A) to (H) at the end of the molecular chain. A linear butadiene-based polymer (B) obtained by polymerizing an organolithium compound having at least one functional group selected from the following as an initiator [hereinafter, simply referred to as "linear butadiene-based polymer (B)" The present invention provides a butadiene-based polymer rubber composition containing at least 15% by weight.

(B) R 1 ³ _M group (wherein, R ¹ is an alkyl group, an aryl group, an allyl group, an aralkyl group, an alkenyl group or an ester group, M is silicon atom, a germanium atom or a tin atom.) ( b) (thio) carbonyl group ^(c) _{R 2} 2 P- group (wherein, ^{R 2} is an alkyl group, an aryl group, an aralkyl group, an alkoxy group or an ester group.) (d) (Here, Y is an oxygen atom or a sulfur atom, and R ² is the same as above.) (E) Amido group (f) Imino group (to) Triazine group (thi) (thio) carboxyl group First, the branched form of the present invention The butadiene-based polymer (A) is obtained by polymerizing with an organolithium compound as an initiator and has a branched structure of three or more branches in the molecular chain, whereby the composition obtained for the first time has good low temperature flow characteristics. And not only good workability, but also excellent breaking strength.

In particular, in order to improve the rolling resistance of the resulting composition,
30 to 80% by weight, preferably 40 to 70% by weight, of the branched butadiene-based polymer of the present invention is preferably composed of a tin-carbon bond or a polyisocyanate coupling.

The proportion of the branched butadiene-based polymer (A) contained in the butadiene-based polymer rubber composition of the present invention is 15% by weight or more, preferably 30 to 80% by weight. It is inferior and not preferable.

Next, the linear butadiene-based polymer (B) of the present invention is polymerized by using an organolithium compound as an initiator, and has a molecular chain terminal selected from the above (a) to (h) in the molecule. It has at least one kind of functional group.

Examples of the compound forming the functional groups (a) to (h) include the following compounds. These compounds may be used alone or in combination of two or more.

That is, the compound forming the ^(b) _{R 1} 3 M- group,
In the general formula ^R ₁ 3 MX (wherein, ^{R 1} represents an alkyl group having 1 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, an allyl group, an aralkyl group having 7 to 18 carbon atoms, alkenyl having 2 to 18 carbon atoms Group is an aliphatic ester group having 1 to 18 carbon atoms or an aromatic ester group having 6 to 18 carbon atoms, M is a silicon atom, a germanium atom or a tin atom, and X is a halogen atom or an ester group. Specifically, monochlorotrimethyltin, monobromotrimethyltin, triphenyltin monochloride, tributyltin chloride, trimethylsilyl chloride, triphenylsilyl chloride, triphenylgermyl chloride, tributyltin stearate, triphenyltin laurate. And so on.

As the compound forming the (b) (thio) carbonyl group, a compound represented by the general formula: (Wherein R ¹ is the same as above, Y is an oxygen atom or a sulfur atom, and X ′ is a halogen atom), and specifically, acetyl chloride, benzoyl chloride, p-dimethylaminobenzoyl chloride. ,
p-dimethylaminothiobenzoyl chloride and the like.

^(C) _{R 2} 2 P- group (wherein, ^{R 2} is an alkyl group having 1 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, 7 carbon atoms
18 aralkyl group, C1-18 alkoxy group or C6-18 aliphatic ester group or C7
~ 18 aromatic ester groups. The compound forming () is, for example, a compound represented by the general formula R ² ₂ PX (R ² and X are the same as defined above), and specific examples thereof include diphenylphosphine chloride and dioctylphosphine chloride.

(D) (Wherein, Y is an oxygen atom or a sulfur atom, and R ² is the same as above), and examples of the compound include those represented by the general formula: (Wherein R ² , Y and X are the same as above), and specifically include diphenylchlorophosphate (diphenylphosphine oxide) and the like.

(E) The compound forming an amide group is represented by, for example, the general formula R ³ NCO (wherein R ³ represents an alkyl group having 1 to 8 carbon atoms and an aromatic group having 6 to 14 carbon atoms). It is a compound, and specific examples thereof include methyl isocyanate, octyl isocyanate, phenyl isocyanate, and phenyl isothiocyanate.

(F) The compound forming an imino group is, for example, a compound represented by the general formula R ¹ -C = N (wherein R ¹ is the same as above), and specifically, acetonitrile, benzonitrile, N -Phenylmaleimide and the like.

As the compound forming the (to) triazine group, a compound represented by the general formula: (Here, R ¹ is the same as above, and R ⁴ is a halogen atom or an acetyl group.) Specifically, 4-chloro-1,3,5-triazine, 4-acetyl- 1,3,5-triazine and the like.

Specific examples of the compound that forms (h) (thio) carboxyl group include carbon dioxide, carbon disulfide, maleic anhydride, fumaric anhydride, and itaconic anhydride.

The proportion of the linear butadiene-based polymer (B) contained in the butadiene-based polymer rubber composition of the present invention is 15% by weight or more, preferably 30 to 80% by weight. The effect of reducing the Pain effect due to the addition of is small.

The vinyl bond content of the butadiene portion of the branched butadiene-based polymer (A) and the linear butadiene-based polymer (B) is not particularly limited, but the vinyl bond content is required to obtain an ultralow heat-generating composition. The content is preferably 40% by weight or less, more preferably 30% by weight or more when a balance with the wet skid resistance characteristic is required, and particularly preferably 50% by weight or more when a high grip property is required.

The content of vinyl compounds in the branched butadiene polymer (A) and the linear butadiene polymer rubber (B) is 0 to 60% by weight, preferably 3 to 45% by weight, and 60% by weight. If it exceeds%, the heat generation properties will be inferior.

Further, the Mooney viscosity (M) of the branched butadiene-based polymer (A) or the linear butadiene-based polymer (B) of the present invention is
L _{1 + 4} , 100 ° C.) is preferably from 10 to 150, and when it is less than 10, the tensile properties of the resulting composition deteriorate,
On the other hand, when it exceeds 150, the workability is deteriorated and neither is preferable.

The branched butadiene-based polymer (A) and the linear butadiene-based polymer (B) of the present invention are butadiene-based monomers,
It can be obtained by carrying out solution polymerization with an organic lithium compound as an initiator in an organic solvent together with a vinyl compound monomer, if necessary.

Here, as the butadiene-based monomer, 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 1-methyl-1,3-butadiene and the like are used. For example, 1,3-butadiene may partially contain a butadiene derivative such as pentadiene.
Of these, 1,3-butadiene is preferable.

As the aromatic vinyl compound, styrene, p-methylstyrene, vinyltoluene, α-methylstyrene, pt
-Butylstyrene and the like are used. Of these, styrene is preferred.

As the organic solvent, hydrocarbon solvents such as pentane, hexane, heptane, octane, methylcyclopentane, cyclohexane, benzene and xylene are used.

Examples of the organolithium compound include n-butyllithium, sec-butyllithium, t-butyllithium,
Alkyllithium such as 1,4-dilithiobutane, alkylenedilithium, and the like are added in an amount of 0.
Used in an amount of 02 to 0.2 parts by weight.

At this time, a Lewis base as a regulator of the vinyl bond content of the microstructure, that is, the butadiene portion, such as an ether or an amine, specifically, diethyl ether, tetrahydrofuran, propyl ether, butyl ether, higher ether, or ethylene glycol dibutyl ether. , An ether derivative of polyethylene glycol such as diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, and triethylene glycol dimethyl ether, and examples of amines include tertiary amines such as tetramethylethylenediamine, pyridine, and tributylamine, which are used together with a solvent.

Further, the polymerization reaction is usually carried out at -30 ° C to + 150 ° C. Particularly, in consideration of the coupling reaction described later, 110 ° C. or lower is preferable.

Further, the polymerization may be carried out while controlling at a constant temperature, or may be carried out at an elevated temperature without heat removal.

The general method for producing a butadiene-based polymer applied in the present invention is as described above. To produce a branched butadiene-based polymer (A) and a linear butadiene-based polymer (B), The following specific formulations are required.

First, in order to produce a branched butadiene-based polymer, an organolithium compound is used as an initiator in a hydrocarbon solvent as described above, and a desired molecular weight of a desired molecular weight is directly determined by the method disclosed in, for example, JP-B-36-15386. It is obtained by preparing a chain butadiene-based polymer and then adding a trifunctional or higher-functional polyfunctional coupling agent in a predetermined ratio.

The coupling agent reacts with the terminal living polymer produced by anionic polymerization. Therefore, the amount of the coupling agent to which the reaction proceeds quantitatively is approximately 1 / n molar amount with respect to 1 mol of the terminal living polymer in the case of a coupling agent having n coupling-capable groups. 100% coupling is performed. The trifunctional or higher functional polyfunctional or higher functional coupling agents among all the coupling agents may be used in a molar ratio such that the polymer is limited by the present invention.

Therefore, in order to obtain the branched butadiene-based polymer (A) of the present invention, for example, when tin tetrachloride or silicon tetrachloride is used as an example of the polyhalide compound as the coupling agent, all four couplings are possible. Since it has such a group, one of tin tetrachloride and silicon tetrachloride or a total amount of 0.0375 mol or more is used per 1 mol of the organolithium compound effectively used as an initiator, simultaneously or separately. In addition, a coupling reaction may be performed.

In producing the branched butadiene polymer (A), the coupling bond between the living polymer and the coupling compound is, for example, a bond between the metal and butadiene constituting the coupling compound, that is, a metal-butadienyl bond. Is a trifunctional or higher functional coupling agent, and is obtained by adding a small amount of 1,3-butadiene (0.5 to 100 mol per 1 g of lithium equivalent of the organic lithium compound) immediately before the coupling reaction. To be

Examples of trifunctional or higher polyfunctional coupling agents include polyhalide compounds, for example, tin halide compounds such as tetrachlorotin, trichloromethyltin, tetrabromotin, and bistrichlorostannylethane; silicon;
Polyhalides of germanium, lead, boron, etc .; hexachlorophosphazene, phosphorus pentachloride, phosphorus trichloride, polyepoxides such as epoxidized soybean oil, triglycidylaminophenol, tetraglycidylaminodiphenylmethane; polyisocyanates such as triene diisocyanate, hexa Methylene isocyanate, methylene diisocyanate, isophorone diisocyanate, crude methylene phenyl isocyanate, aromatic triisocyanate, aromatic tetraisocyanate, aromatic oligoisocyanate; polyhalogenated carbon such as carbon tetrachloride, tetrahalogenated carbon such as tetrachloroethane, chloroform, Trihalogenated carbons such as trichlene; polyesters such as adipic acid diesters, terephthalic acid diesters, dibutyric acid Tin dilaurate, etc. dibutyltin diacetate is used.

Among these coupling agents, tin compounds or polyisocyanates are particularly preferable in order to improve the rolling resistance of the obtained rubber composition.

Next, in order to produce the linear butadiene-based polymer (B), an organolithium compound is used as an initiator in a hydrocarbon solvent as described above.
A linear butadiene-based polymer having a desired molecular weight is prepared by the method described in Japanese Patent No. Sometimes referred to as a "compound").

The functional group-forming compound reacts with the terminal living polymer produced by anionic polymerization. Therefore, the addition amount of the functional group-forming compound in which the reaction proceeds quantitatively is 1 / n molar amount per 1 mol of the terminal living polymer in the case of a functional group-forming compound having n (1-2) functional groups. By adding 100% of the functional groups to the living polymer.

The functional group-forming compound of the present invention in all the functional group-forming compounds,
The molar ratio may be such that the polymer is limited in the present invention.

Therefore, in order to obtain the linear butadiene-based polymer (B) of the present invention, for example, when monochlorotrimethyltin or monochlorotrimethylsilicon is used as the functional group-forming compound, one functional group capable of coupling is used. Therefore, with respect to 1 mol of the organolithium compound effectively used as an initiator, one or more of monochlorotrimethyltin and monochlorotrimethylsilicon is used in a total amount of 0.15 mol or more, and is added simultaneously or separately. A coupling reaction may be performed.

In the production of the linear butadiene-based polymer (B), the binding between the living polymer and the functional group-forming compound is
For example, in order to form a bond between a metal constituting a functional group-forming compound and butadiene, that is, a metal-butadienyl bond, a functional group-forming compound is used, and a small amount of 1,3-butadiene (organolithium compound Lithium 1
It is obtained by adding 0.5 to 100 mol per g atomic equivalent). When a functional group other than a metal is selectively monofunctionally reacted, it can be reacted in the form of a styryl anion.

In order to prepare a composition containing the branched butadiene-based polymer (A) and the linear butadiene-based polymer (B) of the present invention, both prepared separately may be mixed. Also, after the polymerization reaction of the butadiene-based monomer is completed,
First, the coupling agent is added to the polymerization reaction system to cause a coupling reaction, and then the functional group-forming compound is added to the reaction system to obtain a branched butadiene-based polymer (A) and a linear butadiene-based polymer. A mixture with the polymer (B) may be prepared.

The composition solution thus obtained is oil-extended if necessary, and separated, recovered, and post-treated by a conventional method,
A solid composition is obtained.

The butadiene-based polymer rubber composition of the present invention can be blended with other diene-based rubbers such as natural rubber, polyisoprene rubber, polybutadiene rubber, and emulsion-polymerized styrene-butadiene rubber to be used as a rubber composition. . In this case, the butadiene-based polymer (A) of the present invention,
The content of (B) may be 15% by weight or more,
As described above, it is necessary to achieve the effects of the present invention.

Further, if necessary, it is oil-extended, added with a usual compounding agent for vulcanized rubber, and vulcanized to be used for tires, anti-vibration rubbers, belts, hoses, and other industrial products.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples.
The present invention is not limited to the examples as long as the gist of the present invention is not exceeded.

In the examples, parts and% are by weight unless otherwise specified. In addition, various measurements in the examples were based on the following methods.

That is, the number of branches of the branched polymer was calculated from the molecular weight of each peak top in gel permeation chromatography (GPC).

The vinyl bond content was determined by the infrared method (Morero method). The bound styrene content was determined from a calibration curve by infrared method based on the absorption of a phenyl group at 699 cm ^-1 .

Mooney viscosity (ML _{1 + 4} , 100 ° C) is JIS K6
It measured according to 300.

The heat generation characteristics were evaluated by ΔT using a Goodrich flexometer.

The workability was evaluated by visual inspection of the aggregate and gloss of the dump rubber after mixing.

The tensile strength (tensile property) was determined according to JIS K6301.

For the Payne effect, t of the strain curve of tan δ at 50 ° C. measured by a mechanical spectrometer manufactured by RMS
The difference (Δtan δ) between the maximum value and the minimum value of an δ was obtained. Also, from the temperature dispersion curve of tan δ at 15 Hz and 1% strain, tan δ (0 ° C.) and tan δ (30 ° C.)
I asked.

After charging cyclohexane, a monomer and tetrahydrofuran in the reactors of Examples 1 to 10 and Comparative Examples 1 to 210 according to the formulation shown in Table 1, 20 to 90 using the polymerization initiator shown in Table 1. Polymerization was carried out at 1.5 ° C. for 1.5 hours.

Then, the type and amount of the coupling agent or the functional group-forming compound shown in Table 1 was added, and the coupling reaction or the functional group-introducing reaction was carried out at 60 ° C. for 30 minutes. After 3.5 g of 2,6-di-t-butyl-p-cresol was added to the polymer solution, the solvent was removed by steam stripping, and the product was dried on a hot roll at 110 ° C. to obtain a polymer. The properties of the obtained polymer are also shown in Table 1.

Then, using this polymer, according to the formulation shown below, the mixture was mixed and blended with a 230 cc Brabender and a 6-inch roll, and then various measurements were performed using a vulcanized product that was vulcanized at 145 ° C. for 20 minutes. .

The results are shown in Table 2.

Formulation (part) Polymer 100 Carbon black (HAF) 50 Zinc white 3 Stearic acid 1 Anti-aging agent (810NA) ^{* 1} 1 Vulcanization accelerator (DPG) ^{* 2} 0.8〃 (DM) ^{* 3} 0.6 Sulfur 1.5 * 1) N-phenyl-N'-isopropyl-p-phenylenediamine * 2) Diphenylguanidine * 3) Benzothiazyl disulfide [Advantages of the Invention] The butadiene-based polymer rubber composition of the present invention is a composition capable of controlling exothermicity, excellent in fracture properties, and excellent in Payne effect. When blended with, the workability during blending is significantly improved and the vulcanized physical properties are also excellent.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Noboru Shimada 2-11-24 Tsukiji, Chuo-ku, Tokyo Within Nippon Synthetic Rubber Co., Ltd. (72) Akihiko Morikawa 2-11-24 Tsukiji, Chuo-ku, Tokyo Japan Synthetic Rubber Co., Ltd. (72) Inventor Tatsuro Hamada 1-13-3 Akitsu-cho, Higashimurayama-shi, Tokyo (72) Inventor Masayuki Ohashi 1-27-9 Kamitsukaido, Suginami-ku, Tokyo (72) Inventor Tatsuo Fujimaki 3-2-3 Fujimi-cho, Higashimurayama-shi, Tokyo

Claims (1)

[Claims] 1. A rubber component containing at least 15% by weight of a branched butadiene-based polymer (A) obtained by polymerization using an organolithium compound as an initiator, and the following groups (A) to (H) at the end of the molecular chain. At least one linear butadiene polymer (B) obtained by polymerization using an organolithium compound having at least one functional group selected from
The butadiene-based polymer rubber composition is characterized by containing 5% by weight. (B) R 1 ³ _M group (wherein, R ¹ is an alkyl group, an aryl group, an allyl group, an aralkyl group, an alkenyl group or an ester group, M is silicon atom, a germanium atom or a tin atom.) ( b) (thio) carbonyl group ^(c) _{R 2} 2 P- group (wherein, ^{R 2} is an alkyl group, an aryl group, an aralkyl group, an alkoxy group or an ester group.) (d) (Here, Y is an oxygen atom or a sulfur atom, and R ² is the same as above.) (E) Amido group (f) Imino group (to) Triazine group (thi) (thio) carboxyl group