JP4289112B2 - Modified diene polymer rubber and process for producing the same - Google Patents

Description

  The present invention relates to a both-end modified polymer rubber having excellent rebound resilience and a method for producing the same. The both-end modified polymer rubber obtained by this production method is optimal for automobile tires having excellent fuel economy.

  As a rubber for automobile tires, a styrene-butadiene copolymer obtained by an emulsion polymerization method is known. However, since the rebound resilience of the copolymer is inferior, the automobile tire made of the copolymer has a problem that it does not have excellent fuel economy.

  As an attempt to obtain a rubber having excellent rebound resilience, Patent Document 1 includes butadiene and styrene, an organolithium compound as a polymerization initiator, and a Lewis base such as ether as a microstructure modifier. A method of copolymerizing in a hydrocarbon solvent is disclosed.

  Patent Document 2 proposes a method of obtaining a modified diene copolymer rubber having improved rebound resilience by reacting a specific acrylamide with the alkali metal terminal of the diene polymer rubber.

  Patent Document 3 proposes a method of obtaining a modified diene copolymer rubber having improved rebound resilience and processability by reacting a specific amine with the alkali metal terminal of the diene polymer rubber.

JP-A-60-72907 Japanese Patent No. 2540901 JP 2002-128824 A

  However, in recent years, the demand for fuel economy of automobile tires has become more sophisticated against the background of environmental considerations, and the above copolymer rubber cannot sufficiently meet this demand.

  An object of the present invention is to provide a both-end modified polymer rubber having excellent rebound resilience and a method for producing the same.

（式（１）中、ＲはＮ，Ｎ−ジメチルアミノ基、Ｎ，Ｎ−ジエチルアミノ基、Ｎ，Ｎ−ジプロピルアミノ基、Ｎ，Ｎ−ジブチルアミノ基、モルホリノ基又はイミダゾリル基を表し、Ｘは共役ジエンモノマー又は芳香族ビニルモノマーｍユニットの重合からなる炭化水素を表し、ｍは１〜１０の整数を表し、ｎは１〜１０の整数を表し、Ｍはアルカリ金属を表す。）

（式（２）中、Ｒ₁は水素またはメチル基を表し、Ｒ₂及びＲ₃はアルキル基を表し、ｐは１〜１０の整数を表す。）
本発明のうち第二の発明は、上記製造方法から得られる両末端変性重合体ゴムに係るものである。
本発明のうち第三の発明は、該変性重合体ゴムを、ゴム成分中１０重量％以上含有するゴム組成物に係るものである。 First invention of the present invention, Ru good in the following steps, Mooney viscosity (ML 1 + ₄₎ is from 10 to 200, in which both ends according to the modified method of manufacturing a diene polymer rubber is there.
Step 1: In the presence of a compound represented by the following formula (1), a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer are polymerized in a hydrocarbon solvent to obtain an active polymer having an alkali metal terminal. Process for producing Process 2: Process for producing a modified polymer rubber having both ends modified by reacting the active polymer with the acrylamide compound represented by the following formula (2)

(In the formula (1), R represents an N, N-dimethylamino group, an N, N-diethylamino group, an N, N-dipropylamino group, an N, N-dibutylamino group, a morpholino group or an imidazolyl group ; represents a carbon hydride ing from the polymerization of a conjugated diene monomer or an aromatic vinyl monomer m unit, m represents an integer of 1 to 10, n represents an integer of 1 to 10, M represents an alkali metal.)

(In formula (2), R ₁ represents hydrogen or a methyl group, R ₂ and R ₃ represent an alkyl group, and p represents an integer of 1 to 10.)
The second aspect of the present invention according to both terminal-modified polymer rubber obtained from above SL Manufacturing method.
The third invention of the present invention relates to a rubber composition containing the modified polymer rubber in an amount of 10% by weight or more in the rubber component.

  According to the present invention, it is possible to provide a both-end modified polymer rubber excellent in fuel economy and a method for producing the same.

  Examples of the conjugated diene monomer used in the present invention include 1,3-butadiene, isoprene, 1,3-pentadiene (piperine), 2,3-dimethyl-1,3-butadiene, 1,3-hexadiene, and the like. Can do. Among these, 1,3-butadiene and isoprene are preferable from the viewpoint of availability and the physical properties of the resulting modified polymer rubber.

  Examples of the aromatic vinyl monomer used in the present invention include styrene, α-methylstyrene, vinyl toluene, vinyl naphthalene, divinyl benzene, trivinyl benzene, and divinyl naphthalene. Among these, styrene is preferable from the viewpoint of availability and the physical properties of the resulting modified polymer rubber.

In the formula (1), preferably R is a N, N-dimethylamino group, N, N-diethylamino group, N, N-dipropylamino group, N, N-dibutylamino group, a morpholino group, imidazolinium Le group .

In formula (1), X represents a carbon hydride ing from the polymerization of a conjugated diene monomer or an aromatic vinyl monomer m unit, m is an integer of 0 to 10, when m is 0, a solution The association rate is strong and the solubility in a hydrocarbon solvent is deteriorated, so that the polymerization rate may be slow. When m is 5 or more, the molecular weight increases and the amount used increases, such being undesirable. Particularly in the case of coal hydrocarbons ing a polymer of isoprene monomer 2 units of excellent solubility in a hydrocarbon solvent are preferred.

  In formula (1), n is an integer of 1 to 10, but an integer of 3 to 10 is preferable. In the case of 3 or less, since the reactivity of the compound is high, synthesis is difficult and polymerization is difficult to control.

  In the formula (1), M represents an alkali metal, and examples thereof include Li, Na, K, Cs, etc., but Li having high solubility in a hydrocarbon solvent is preferable.

Examples of the compound represented by the formula (1) include 3- (N, N-dimethylamino) -1-propyllithium, 3- (N, N-diethylamino) -1-propyllithium, 3- (N, N- dipropylamino) -1-propyl lithium, 3- (N, N-dibutylamino) -1-propyl lithium, 3-morpholino-1-propyl lithium, 3- imidazolinium-1-propyl lithium, and these butadiene , Isoprene, or compounds extended in chain by 1 to 10 units of styrene, and the like. An active polymer having a narrow molecular weight distribution can be obtained by a rapid reaction, and the resulting polymer can significantly improve fuel economy. To 3- (N, N-dimethylamino) -1-propyllithium and 3- (N, N-dimethylamino) -1-propyllithium Over 2 units active charcoal hydrogen obtained by polymerization is preferred. More industrially excellent solubility in a hydrocarbon solvent, 3- (N, N- dimethylamino) -1-propyl active charcoal of hydrogen lithium to polymerize the isoprene monomer 2 units are preferred.

  When a combination of a conjugated diene monomer and an aromatic vinyl monomer is used in Step 1 of the present invention, the weight ratio of the conjugated diene monomer / aromatic vinyl monomer is preferably 50/50 to 90/10, and 55/45 to 85 / 15 is more preferable. When the ratio is less than 50/50, the resulting active polymer becomes insoluble in the hydrocarbon solvent, and as a result, uniform polymerization may not be possible. If the ratio exceeds 90/10, the strength of the resulting active polymer may be reduced.

  The polymerization method in Step 1 is not particularly limited, and may be a known method. In the process, hydrocarbon solvents; randomizers; and additives for adjusting the content of vinyl bonds (derived from conjugated diene monomers) in the resulting active polymer are commonly used. Known solvents and additives may be used.

  The hydrocarbon solvent is a solvent that does not deactivate the compound represented by the formula (1). Suitable solvents can include aliphatic hydrocarbons, aromatic hydrocarbons, and alicyclic hydrocarbons. Particularly suitable solvents are those having 2 to 12 carbon atoms. As a solvent, propane, n-butane, iso-butane, n-pentane, iso-pentane, n-hexane, cyclohexane, propene, 1-butene, iso-butene, trans-2-butene, cis-2-butene, 1 -Pentene, 2-pentene, 1-hexene, 2-hexene, benzene, toluene, xylene, and ethylbenzene, and combinations of at least two of these.

  Examples of the additive for adjusting the vinyl bond content include a Lewis basic compound. The compound is preferably an ether or a tertiary amine from the viewpoint of easy availability when industrially carried out.

  As the ether, cyclic ethers such as tetrahydrofuran, tetrahydropyran, and 1,4-dioxane; aliphatic monoethers such as diethyl ether and dibutyl ether; ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol diethyl Examples include ethers and aliphatic diethers such as diethylene glycol dibutyl ether; and aromatic ethers such as diphenyl ether and anisole.

  Examples of the tertiary amine include triethylamine, tripropylamine, tributylamine, N, N, N ′, N′-tetramethylethylenediamine, N, N-diethylaniline, pyridine, and quinoline.

In formula (2), R ₁ represents hydrogen or a methyl group, and R ₂ and R ₃ represent an alkyl group, and those having 2 to 4 carbon atoms are preferred from the viewpoint of fuel economy.

  In formula (2), p represents an integer of 1 to 10, but an integer of 2 to 5 is preferable. In the case of 5 or more, the molecular weight increases and the amount of acrylamide compound used increases.

  As the compound represented by the formula (2), N, N-dimethylaminomethylacrylamide, N, N-ethylmethylaminomethylacrylamide, N, N-diethylaminomethylacrylamide, N, N-ethylpropylaminomethylacrylamide, N, N-dipropylaminomethylacrylamide, N, N-butylpropylaminomethylacrylamide, N, N-dibutylaminomethylacrylamide, N, N-dimethylaminoethylacrylamide, N, N-ethylmethylaminoethylacrylamide, N, N- Diethylaminoethylacrylamide, N, N-dimethylaminoethylacrylamide, N, N-emethylpropylaminoethylacrylamide, N, N-dipropylaminoethylacrylamide, N, N-butylpropylaminoe Acrylamide, N, N-dibutylaminoethylacrylamide, N, N-dimethylaminopropylacrylamide, N, N-ethylmethylaminopropylacrylamide, N, N-diethylaminopropylacrylamide, N, N-ethylpropylaminopropylacrylamide, N , N-dipropylaminopropylacrylamide, N, N-butylpropylaminopropylacrylamide, N, N-dibutylaminopropylacrylamide, N, N-dimethylaminobutylacrylamide, N, N-ethylmethylaminobutylacrylamide, N, N -Diethylaminobutylacrylamide, N, N-ethylpropylaminobutylacrylamide, N, N-dipropylaminobutylacrylamide, N, N-butylpropylaminobutyl Le acrylamide, N, N- dibutyl-aminobutyl acrylamide, and these methacrylamide, and the like, N from the viewpoint of fuel economy can be remarkably improved, N- dimethylaminopropyl acrylamide are preferred.

  The usage-amount of an acrylamide compound is 0.1-10 mol normally with respect to 1 mol of active polymers, Preferably it is 0.5-2 mol. If the amount used is less than 0.1 mol, the effect of improving fuel economy is small, and if the amount used exceeds 10 mol, an unreacted acrylamide compound remains in the solvent, which is economically undesirable. . This is because, when the solvent is recycled and reused, a step of separating the acrylamide compound in the solvent is necessary.

  The reaction in step 2 proceeds rapidly. As a preferred contact method, a method of adding an acrylamide compound to the reaction mixture obtained in step 1 can be exemplified. The reaction temperature is generally room temperature to 80 ° C., and the reaction time is generally several seconds to several hours.

From the viewpoint of kneading processability of the modified polymer rubber, before or after step 2, the active polymer is represented by the following formula (wherein R ′ is an alkyl group, alkoxy group, allyl group, alkenyl group, cycloalkenyl group or aromatic A coupling agent represented by a group hydrocarbon group, M ′ is a silicon or tin atom, Y is a halogen atom, a is an integer of 0 to 2, and b is an integer of 2 to 4) may be added.
R'aM'Yb

  The amount of the coupling agent added is usually 0.005 to 0.4 mol, preferably 0.01 to 0.3 mol, per mol of the active polymer. When the added amount is less than 0.005 mol, the effect of improving the processability of the modified polymer rubber is small. When the added amount exceeds 0.3 mol, the ratio of the active polymer that reacts with the acrylamide compound is reduced, so that the effect of improving fuel economy is reduced. Also, the viscosity of the solution can be very high.

  The modified polymer rubber in the reaction mixture obtained in step 2 is usually used in the production of rubber by a solution polymerization method (1) a method of adding a coagulant or (2) a method of adding steam. It is solidified by a simple coagulation method. The solidification temperature is not particularly limited.

  The coagulated modified polymer rubber is dried by a known drier used in the production of synthetic rubber, such as a band drier or an extrusion drier. The drying temperature is not particularly limited.

The resulting modified polymer rubber has a Mooney viscosity (ML _{1 + 4} ) of preferably 10 to 200, more preferably 20 to 150. If the viscosity is less than 10, mechanical properties such as the tensile strength of the vulcanizate may deteriorate. When the viscosity exceeds 200, the miscibility in the case of using it as a composition in combination with other rubber is deteriorated, so that it becomes difficult to process. As a result, the mechanical properties of the vulcanized product of the resulting rubber composition are reduced. May decrease.

  The content of the vinyl bond derived from the conjugated diene monomer unit in the modified polymer rubber obtained is preferably 10 to 70%, more preferably 15 to 60%. When the content is less than 10%, the glass transition temperature of the polymer rubber is lowered, and as a result, the grip performance of a tire made of the polymer rubber may be inferior. When the content exceeds 70%, the glass transition temperature of the polymer rubber increases, and as a result, the rebound resilience of the polymer rubber may be inferior.

  The resulting modified polymer rubber may be used in combination with components such as other rubbers and additives.

  As the other rubber, a styrene-butadiene copolymer rubber obtained by an emulsion polymerization method; a polybutadiene rubber, a butadiene-isoprene rubber copolymer obtained by a solution polymerization method using a catalyst such as an anionic polymerization catalyst or a ziegler type catalyst. Examples include rubber and styrene-butadiene copolymer rubber; natural rubber; and combinations of at least two of these rubbers.

  The ratio of the latter in the rubber composition comprising the other rubber and the modified polymer rubber is preferably 10% by weight or more, more preferably 20% by weight or more, with the total amount of both being 100% by weight. When the proportion is less than 10% by weight, the rebound resilience of the resulting rubber composition is difficult to improve, and the processability is not improved.

  What is necessary is just to determine the kind and addition amount of the said additive according to the intended purpose of the rubber composition obtained. As additives, vulcanizing agents commonly used in the rubber industry, such as sulfur; stearic acid; zinc white; thiazole vulcanization accelerator, thiuram vulcanization accelerator and sulfenamide vulcanization accelerator Organic peroxides; reinforcing agents such as carbon black grades such as HAF and ISAF; silica; fillers such as calcium carbonate and talc; extension oils; processing aids; and anti-aging The agent can be exemplified.

  The method for producing the rubber composition is not limited. Examples of the production method include a method of kneading each component with a known mixer such as a roll or Banbury. The resulting rubber composition is usually vulcanized and used as a vulcanized rubber composition.

  Since the modified polymer rubber of the present invention is excellent in rebound resilience and processability, the rubber composition comprising the rubber is optimal as a rubber for automobile tires excellent in fuel economy. The rubber composition can also be used for applications such as for shoe soles, flooring, and anti-vibration rubber.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.
Example 1
After washing and drying a stainless polymerization reactor having an internal volume of 20 liters, the reactor was replaced with dry nitrogen. Then, an active saturated or unsaturated hydrocarbon (AI-200 CE (manufactured by FMC Lithium)) cyclohexane solution 11 obtained by polymerizing 2 units of isoprene monomer to 3- (N, N-dimethylamino) -1-propyllithium. 0.2 mmol), 1420 g of 1,3-butadiene, 580 g of styrene, 324 g of tetrahydrofuran, and 10.2 kg of hexane were polymerized at 65 ° C. for 3 hours with stirring. After adding 0.4 mmol of tin tetrachloride (coupling agent) to the resulting polymerization reaction mixture and reacting at 65 ° C. for 30 minutes with stirring, 9.6 mmol of N, N-dimethylaminopropylacrylamide (acrylamide compound) And allowed to react for an additional 30 minutes at 65 ° C. with stirring. 10 ml of methanol was added to the obtained reaction mixture, and the mixture was further stirred at 65 ° C. for 5 minutes. The obtained reaction mixture was taken out, 10 g of 2,6-di-t-butyl-p-cresol (Sumitomo Chemical's BHT: the same applies hereinafter) was added thereto, and most of the hexane was evaporated. And dried under reduced pressure at 55 ° C. for 12 hours to obtain a polymer rubber modified at both ends.

Comparative Example 1
11.2 mmol of active saturated or unsaturated hydrocarbon (AI-200 CE (manufactured by FMC Lithium) cyclohexane solution) obtained by polymerizing 2 units of isoprene monomer to 3- (N, N-dimethylamino) -1-propyllithium. n-butyllithium (n-hexane solution) was changed to 12.5 mmol, the addition amount of tin tetrachloride (coupling agent) was changed to 1.63 mmol, and N, N-dimethylaminopropylacrylamide (acrylamide) A modified polymer rubber was obtained in the same manner as in Example 1 except that the amount of compound) was changed to 5.63 mmol.

Comparative Example 2
The addition amount of n-butyllithium (n-hexane solution) was changed to 9.4 mmol, the addition amount of THF was changed to 122 g, tin tetrachloride (coupling agent) and N, N-dimethylaminopropylacrylamide A polymer rubber was obtained in the same manner as in Comparative Example 1 except that (acrylamide compound) was not added.

The following measurements were performed on the both-end-modified polymer rubber obtained in Example 1 and the polymer rubber obtained in Comparative Examples 1 and 2, and the results are summarized in Table 2.
1. Mooney viscosity Measured at 100 ° C. according to JIS K-6300.
2. Vinyl content Measured by infrared spectroscopy.
3. Styrene unit content Measured by the refractive index method.
4). Rebound resilience of vulcanized rubber The modified polymer rubber or polymer rubber was kneaded with a lab plast mill, and the kneaded product was molded with a 6-inch roll to obtain a sheet. The sheet was vulcanized by heating at 160 ° C. for 45 minutes, and then the rebound resilience at 60 ° C. of the vulcanized sheet was measured with a Lupke Resilience Tester.

* 1: Ultrasil VN3-G (Degussa Co., Ltd.)
* 2: Si69 (Degussa)
* 3: X-140 (Aroma oil manufactured by Kyodo Oil Co., Ltd.)
* 4: Antigen 3C (Anti-aging agent manufactured by Sumitomo Chemical Co., Ltd.)
* 5: Soccinol CZ (vulcanization accelerator manufactured by Sumitomo Chemical Co., Ltd.)
* 6: Soxinol D (vulcanization accelerator manufactured by Sumitomo Chemical Co., Ltd.)
* 7: Sunnock N (Ouchi Shinsei Chemical Co., Ltd.)

* 1 Compound represented by formula (1) I: Active saturated or unsaturated hydrocarbon obtained by polymerizing 2 units of isoprene monomer on 3- (N, N-dimethylamino) -1-propyllithium * 2 Modifier
II: N, N-dimethylaminopropylacrylamide

Claims (9)

Following Ru good in step a Mooney viscosity (ML 1 + ₄₎ is from 10 to 200, the production method of the diene polymer rubber in which both ends are modified.
Step 1: In the presence of a compound represented by the following formula (1), a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer are polymerized in a hydrocarbon solvent to obtain an active polymer having an alkali metal terminal. Process for producing Process 2: Process for producing a modified polymer rubber having both ends modified by reacting the active polymer with the acrylamide compound represented by the following formula (2)

(In the formula (1), R represents an N, N-dimethylamino group, an N, N-diethylamino group, an N, N-dipropylamino group, an N, N-dibutylamino group, a morpholino group or an imidazolyl group ; represents a carbon hydride ing from the polymerization of a conjugated diene monomer or an aromatic vinyl monomer m unit, m represents an integer of 1 to 10, n represents an integer of 1 to 10, M represents an alkali metal.)

(In formula (2), R ₁ represents hydrogen or a methyl group, R ₂ and R ₃ represent an alkyl group, and p represents an integer of 1 to 10.) The method for producing a double-end modified polymer rubber according to claim 1, wherein, in the formula (1), X is a hydrocarbon formed by polymerization of butadiene, isoprene, or styrene. The method for producing a both-end-modified polymer rubber according to claim 1 or 2, wherein n is 3 to 10 in the formula (1). In Formula (1), M is Li, The manufacturing method of the both-ends modified polymer rubber in any one of Claims 1-3. The method for producing a both-end modified polymer rubber according to any one of claims 1 to 4, wherein in the formula (1), X is a hydrocarbon formed by polymerization of 2 units of isoprene monomer. In formula (2), R ₁ Is hydrogen or a methyl group, R ₂ And R _Three 6 is an alkyl group having 2 to 4 carbon atoms, and p is an integer of 2 to 5. Both-end-modified polymer rubber according to any one of claims 1 to 5. The both-ends modified polymer rubber according to any one of claims 1 to 6, wherein the content of vinyl bonds derived from the conjugated diene monomer unit is 10 to 70%. The both-ends modified polymer rubber obtained by the manufacturing method in any one of Claims 1-7. A rubber composition containing 10% by weight or more of a both-end modified polymer rubber obtained by the production method according to claim 1 in a rubber component.