JP2004277694A - Modified diene polymer rubber and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymer rubber having both ends modified which exhibits an excellent fuel-saving property and its manufacturing method. <P>SOLUTION: The diene polymer rubber having both ends modified is obtained by the following steps: step 1 for manufacturing an active polymer having an alkali metal end by polymerizing a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer in the presence of a compound represented by formula (1) (wherein R is an N-substituted functional group; X is a saturated or unsaturated hydrocarbon obtained by polymerization of m units of the conjugated diene monomer or the aromatic vinyl monomer; m is an integer of 0-10; n is an integer of 1-10; and M is an alkali metal); and step 2 for manufacturing the modified polymer rubber having both ends modified by reacting the active polymer with a ketone compound represented by formula (2) (wherein R<SB>1</SB>is a 1-8C alkyl or alkoxy group, a phenyl group or a benzyl group; and R<SB>2</SB>is an N-substituted cyclic amino group). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a polymer modified at both ends having excellent rebound resilience and a method for producing the same. The double-ended polymer rubber obtained by this production method is most suitable for an automobile tire having excellent fuel economy.

  A styrene-butadiene copolymer obtained by an emulsion polymerization method is known as a rubber for automobile tires. However, since the rebound resilience of the copolymer is inferior, an 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 discloses that butadiene and styrene are used as a polymerization initiator using an organolithium compound, and a Lewis base such as ether is used as a microstructure modifier, A method of copolymerizing in a hydrocarbon solvent is disclosed.

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

  Patent Document 3 proposes a method of reacting a specific amine with an alkali metal terminal of a diene polymer rubber to obtain a modified diene copolymer rubber having improved rebound resilience and workability.

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

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

  It is an object of the present invention to provide a polymer modified at both ends having excellent rebound resilience and a method for producing the same.

（式（１）中、ＲはＮ置換の官能基を表わし、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飽和又は不飽和炭化水素を表し、ｍは０〜１０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は炭素数が１〜８のアルキル基、又はアルコキシ基、フェニル基又はベンジル基を表わし、Ｒ₂はＮ置換の環状アミノ基を表す。）
本発明のうち第二の発明は、上記の工程による両末端変性重合体ゴムの製造方法に係るものである。
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。 The first invention of the present invention relates to a diene polymer rubber having both ends modified, which is obtained from the following steps.
Step 1: a step of polymerizing a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer in the presence of a compound represented by the following formula (1) to produce an active polymer having an alkali metal terminal Step 2 : A step of reacting the active polymer with a ketone compound represented by the following formula (2) to produce a modified polymer rubber having both ends modified:

(In the formula (1), R represents an N-substituted functional group, X represents a saturated or unsaturated hydrocarbon obtained by polymerizing m units of a conjugated diene monomer or an aromatic vinyl monomer, and m represents an integer of 0 to 10. And n represents an integer of 1 to 10, and M represents an alkali metal.)

(In the formula (2), R ₁ represents an alkyl group having 1 to 8 carbon atoms, or an alkoxy group, a phenyl group or a benzyl group, and R ₂ represents an N-substituted cyclic amino group.)
The second invention of the present invention relates to a method for producing a polymer modified at both ends by the above steps.
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 a rubber component.

  As described above, the present invention has provided a double-ended 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, and 1,3-hexadiene. Can be. Among these, 1,3-butadiene and isoprene are preferred from the viewpoints of availability and physical properties of the resulting modified polymer rubber.

  Examples of the aromatic vinyl monomer used in the present invention include styrene, α-methylstyrene, vinyltoluene, vinylnaphthalene, divinylbenzene, trivinylbenzene, and divinylnaphthalene. Among them, styrene is preferred from the viewpoint of availability and physical properties of the modified polymer rubber obtained.

  In the formula (1), preferred R is N, N-dimethylamino, N, N-diethylamino, N, N-dipropylamino, N, N-dibutylamino, morpholino, or imidazole.

  In the formula (1), X represents a saturated or unsaturated hydrocarbon obtained by polymerization of m units of a conjugated diene monomer or an aromatic vinyl monomer, and m represents an integer of 0 to 10; Integers are preferred. When m is 0, the association in the solution is strong and the solubility in the hydrocarbon solvent is deteriorated, so that the polymerization rate may be slowed down. If m is 5 or more, the molecular weight increases, and the amount used is undesirably increased. In particular, the case of a saturated or unsaturated hydrocarbon composed of a polymer of 2 units of isoprene monomer having excellent solubility in a hydrocarbon solvent is preferable.

  In the formula (1), n is an integer of 1 or more and 10 or less, and preferably an integer of 3 or more and 10 or less. In the case of 3 or less, the reactivity of the compound is high, so that the synthesis is difficult and the polymerization is difficult to control.

  In the formula (1), M represents an alkali metal, and examples thereof include Li, Na, K, and Cs, 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-propyllithium, 3- (N, N-dibutylamino) -1-propyllithium, 3-morpholino-1-propyllithium, 3-imidazole-1-propyllithium, and butadiene, isoprene Or a compound in which the chain is extended by 1 to 10 units of styrene. An active polymer having a narrow molecular weight distribution can be obtained by a rapid reaction, and the obtained polymer can be significantly improved in fuel economy. -(N, N-dimethylamino) -1-propyllithium and 3- (N, N-dimethylamino) -1-propyllithium Over 2 units active saturated or unsaturated hydrocarbons polymerized is preferable. Further, industrially, an active saturated or unsaturated hydrocarbon obtained by polymerizing 2-unit of isoprene monomer with 3- (N, N-dimethylamino) -1-propyllithium, which is excellent in solubility in a hydrocarbon solvent, is preferable.

  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 conjugated diene monomer / aromatic vinyl monomer is preferably 50/50 to 90/10, and 55/45 to 85/85. 15 is more preferred. When the ratio is less than 50/50, the obtained active polymer becomes insoluble in a hydrocarbon solvent, and as a result, uniform polymerization may not be possible. If the ratio exceeds 90/10, the strength of the obtained active polymer may decrease.

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

  The above-mentioned hydrocarbon solvent is a solvent that does not deactivate the compound represented by the formula (1). Suitable solvents include aliphatic, aromatic and alicyclic hydrocarbons. Particularly suitable solvents are those having 2 to 12 carbon atoms. As the 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 them.

  As an additive for adjusting the content of the vinyl bond, a Lewis basic compound can be exemplified. As the compound, ether or a tertiary amine is preferable from the viewpoint of easy availability in industrial practice.

  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 Ethers and aliphatic diethers such as diethylene glycol dibutyl ether; and aromatic ethers such as diphenyl ether and anisole can be exemplified.

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

In the formula (2), R ₁ represents an alkyl group having 1 to 8 carbon atoms, or an alkoxy group, a phenyl group or a benzyl group. From the viewpoint of reactivity, a methyl group, an ethyl group, a propyl group, a butyl group, Those having a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a phenyl group or a benzyl group are preferred.

In the formula (2), R ₂ represents an N-substituted cyclic amino group, and examples thereof include morpholine, imidazoline, imidazole, pyrazole, oxazine, and thiazine. It is also possible to use derivatives of heterocyclic compounds having a nitrogen element such as oxazole, thiazole, pyridine, pyrimidine and pyrazine. Among them, morpholine or imidazole is preferable from the viewpoint of improving fuel economy.

  As the compounds represented by the formula (2), 4-morpholinoacetophenone, 4-morpholinobenzophenone, 4 ′-(imidazol-1-yl) -acetophenone, 4 ′-(imidazol-1-yl) -benzophenone, 4-pyrazolyl Examples thereof include acetophenone and 4-pyrazolylbenzophenone, and from the viewpoint that fuel efficiency can be significantly improved, 4-morpholinobenzophenone, 4-morpholinoacetophenone or 4 ′-(imidazol-1-yl) -acetophenone is preferable.

  The amount of the ketone compound to be used is generally 0.1 to 10 mol, preferably 0.5 to 2 mol, per 1 mol of the active polymer. When the amount is less than 0.1 mol, the effect of improving fuel economy is small, and when the amount exceeds 10 mol, unreacted ketone compound remains in the solvent, which is not economically preferable. . This is because, when the solvent is recycled and reused, a step of separating the ketone compound in the solvent is required.

  The reaction of step 2 proceeds rapidly. As a preferable contact method, a method of adding a ketone compound to the reaction mixture obtained in Step 1 can be exemplified. Reaction temperatures are generally between room temperature and 80 ° C., and reaction times are generally between seconds and 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, an alkoxy group, an allyl group, an alkenyl group, a cycloalkenyl group or an aromatic group). 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).

R'aM'Yb
The amount of the coupling agent to be added is generally 0.005 to 0.4 mol, preferably 0.01 to 0.3 mol, per 1 mol of the active polymer. When the amount is less than 0.005 mol, the effect of improving the processability of the modified polymer rubber is small. If the amount exceeds 0.3 mol, the proportion of the active polymer that reacts with the ketone compound decreases, so that the effect of improving fuel economy is reduced. Also, the viscosity of the solution may be very high.

  The modified polymer rubber in the reaction mixture obtained in the step 2 can be prepared by a method such as (1) a method of adding a coagulant or (2) a method of adding steam, which is usually performed in rubber production by a solution polymerization method. Is coagulated by a simple coagulation method. The solidification temperature is not particularly limited.

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

The Mooney viscosity (ML _{1 + 4} ) of the resulting modified polymer rubber is preferably from 10 to 200, more preferably from 20 to 150. If the viscosity is less than 10, mechanical properties such as tensile strength of the vulcanized product may be reduced. When the viscosity is more than 200, the miscibility when used as a composition in combination with another rubber becomes worse, so that it becomes difficult to process, and as a result, the mechanical properties of the vulcanized product of the obtained rubber composition are reduced. May decrease.

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

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

  Styrene-butadiene copolymer rubber obtained by an emulsion polymerization method; polybutadiene rubber, butadiene-isoprene rubber copolymer obtained by a solution polymerization method using a catalyst such as an anion polymerization catalyst or a ziegler type catalyst 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 at least 10% by weight, more preferably at least 20% by weight, with the total amount of both as 100% by weight. When the proportion is less than 10% by weight, the resilience of the obtained rubber composition is hardly improved, and the processability is not improved.

  The type and amount of the above additives may be determined according to the intended use of the obtained rubber composition. As additives, vulcanizing agents such as sulfur commonly used in the rubber industry; stearic acid; zinc white; thiazole vulcanization accelerators, thiuram vulcanization accelerators and sulfenamide vulcanization accelerators. Organic peroxides; reinforcing agents such as carbon black of grades such as HAF and ISAF; silicas; fillers such as calcium carbonate and talc; extender oils; processing aids; Agents 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 a Banbury. The obtained rubber composition is usually vulcanized and used as a vulcanized rubber composition.

  Since the modified polymer rubber of the present invention has excellent rebound resilience and workability, a rubber composition comprising the rubber is most suitable as a rubber for automobile tires having excellent fuel economy. The rubber composition can also be used for applications such as shoe soles, flooring agents, and rubber cushions.

  Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

Example 1
After washing and drying a stainless steel 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-unit of isoprene monomer with 3- (N, N-dimethylamino) -1-propyllithium was added. .2 mmol), 14,20 g of 1,3-butadiene, 580 g of styrene, 324 g of tetrahydrofuran, and 10.2 kg of hexane, and polymerized at 65 ° C. for 3 hours with stirring. 0.4 mmol of tin tetrachloride (coupling agent) was added to the obtained polymerization reaction mixture, and the mixture was reacted at 65 ° C. for 30 minutes with stirring. ) 9.6 mmol was added and reacted at 65 ° C. for another 30 minutes 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. After taking out the obtained reaction mixture and adding thereto 10 g of 2,6-di-t-butyl-p-cresol (Sumilyzer BHT manufactured by Sumitomo Chemical Co., Ltd .: the same applies hereinafter), most of the hexane was evaporated and then And dried under reduced pressure at 55 ° C. for 12 hours to obtain a polymer rubber having both ends modified.

Comparative Example 1
11.2 mmol of an active saturated or unsaturated hydrocarbon (AI-200 CE (manufactured by FMC Lithium) in cyclohexane) obtained by polymerizing 2-unit of isoprene monomer with 3- (N, N-dimethylamino) -1-propyllithium n-butyllithium (n-hexane solution) was changed to 9.55 mmol, the addition amount of THF was changed to 122 g, the addition amount of tin tetrachloride (coupling agent) was changed to 0.57 mmol, and A modified polymer rubber was obtained in the same manner as in Example 1, except that the addition amount of 4,4 '-(imidazol-1-yl) -acetophenone (ketone compound) was changed to 7.27 mmol.

Comparative Example 2
The addition amount of n-butyllithium (n-hexane solution) was changed to 9.80 mmol, the addition amount of THF was changed to 324 g, and the addition amount of tin tetrachloride (coupling agent) was changed to 0.39 mmol. The procedure of Example 1 was repeated, except that the addition amount of 4 ′-(imidazol-1-yl) -acetophenone (ketone compound) was changed to 8.33 mmol, to obtain a modified polymer rubber.

Comparative Example 3
The amount of n-butyllithium (n-hexane solution) was changed to 9.4 mmol, and tin tetrachloride (coupling agent) and 4 ′-(imidazol-1-yl) -acetophenone (ketone compound) were added. A polymer rubber was obtained in the same manner as in Comparative Example 1, except that no polymer rubber was obtained.

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

* 1: Ultrasil VN3-G (manufactured by Degussa Corporation)
* 2: Si69 (made by Degussa)
* 3: X-140 (Aroma oil manufactured by Kyodo Sekiyu)
* 4: Antigen 3C (Anti-aging agent manufactured by Sumitomo Chemical Co., Ltd.)
* 5: Succinol CZ (vulcanization accelerator manufactured by Sumitomo Chemical Co., Ltd.)
* 6: Succinol D (vulcanization accelerator manufactured by Sumitomo Chemical Co., Ltd.)
* 7: Sunnock N (Ouchi Shinko 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: 4 '-(imidazol-1-yl) -acetophenone

Claims (10)

A diene polymer rubber having both ends modified, obtained from the following steps.
Step 1: a step of polymerizing a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer in the presence of a compound represented by the following formula (1) to produce an active polymer having an alkali metal terminal Step 2 : A step of reacting the active polymer with a ketone compound represented by the following formula (2) to produce a modified polymer rubber having both ends modified:

(In the formula (1), R represents an N-substituted functional group, X represents a saturated or unsaturated hydrocarbon obtained by polymerizing m units of a conjugated diene monomer or an aromatic vinyl monomer, and m represents an integer of 0 to 10. And n represents an integer of 1 to 10, and M represents an alkali metal.)

(In the formula (2), R ₁ represents an alkyl group having 1 to 8 carbon atoms, or an alkoxy group, a phenyl group or a benzyl group, and R ₂ represents an N-substituted cyclic amino group.) In the formula (1), R is 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 imidazole group. The polymer modified at both ends according to the above. The double-ended polymer rubber according to claim 1, wherein m is an integer of 0 to 5 in the formula (1). The double-ended polymer rubber according to claim 1, wherein in the formula (1), n is an integer of 3 to 10. 2. The double-ended polymer rubber according to claim 1, wherein in the formula (1), X is a saturated or unsaturated hydrocarbon obtained by polymerizing 2 units of isoprene monomer. The double-ended polymer rubber according to claim 1, wherein M is Li in the formula (1). 2. The polymer according to claim 1, wherein R ₁ is a methyl group, an ethyl group, a propyl group, a butyl group, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a phenyl group or a benzyl group. Rubber. The double-ended polymer rubber according to claim 1, wherein in the formula (2), R ₂ is a morpholino group or an imidazole group. A method for producing a polymer modified at both ends by the process according to claim 1 in a hydrocarbon solvent. A rubber composition containing the double-ended polymer rubber according to claim 1 in an amount of 10% by weight or more in a rubber component.