TWI580697B - A method for producing a diene-based rubber, and a diene-based rubber obtained - Google Patents

Description

Method for producing diene rubber without menstrual coloring and diene rubber obtained thereby

The present invention relates to a method for producing a diene-based rubber which is resistant to time-dependent coloration which is formed in a conventional diene rubber, and a diene rubber obtained thereby.

In general, many diene rubbers are added with various compounds such as various catalysts, auxiliary catalysts, and stabilizers in the production steps. In particular, the stability of the product is achieved by the addition of a stabilizer, so that such an additive must be added. However, if the type or amount of the additive is large, side effects such as coloring or odor are often generated, which may cause unexpected problems.

In particular, when coloring occurs, the use of the product for transparency and the use of the color to be desired are often a large problem, and a large number of solutions have been sought hitherto.

For example, in Patent Document 1, in the production of a polymer of chloroprene, diethylhydroxylamine and a phenolic anti-aging agent are used in combination as a polymerization terminator to prevent coloration.

Further, in Patent Document 2, after the polymerization of the butadiene rubber, one or more kinds of phenolic compounds are mixed, and the pH is adjusted to be in the range of 4 to 11, and the oxygen content is adjusted to 0 to 0.3 ppm. Provides a stable and colorless polybutadiene rubber.

Further, in the prior literature 3, when the polymer is polymerized, it is resistant to oxidation. The blend of the agent or the polymerization inhibitor is added to one or more compounds selected from the group consisting of an arylphosphine compound and a decazane compound by external blending, thereby preventing coloration.

However, in most cases, any of the anti-staining methods is further added to the additives used in the conventional manufacturing steps, and the manufacturing steps become more complicated, and it is difficult to have an advantage in terms of cost.

Therefore, the inventors of the present invention have improved the coloring by controlling the ratio of the organoaluminum and the antioxidant as shown in Patent Document 4. Further, as shown in Patent Document 5, a method of producing an excellent color over time is invented by optimizing the aging time of the organic aluminum and water.

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Publication No. 06-345832

[Patent Document 2] Japanese Patent Publication No. 2003-535926

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2009-249308

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2011-195632

[Patent Document 5] Japanese Patent Laid-Open Publication No. 2011-201972

The inventors of the present invention have reduced the coloring over time by the methods of Patent Documents 4 and 5, but are in a situation where the demand is further improved. In the previous studies, in order to compare the experimental conditions with a certain amount, the aging temperature was uniformly set to 20 ° C, and then the change of the aging time was compared. For example, in Example 1 of Patent Document 5, water is added. After stirring and dissolving in the raw material mixed solution, the mixture was lowered to 10 ° C, and then organoaluminum was added. The organic aluminum and water cause a temperature rise due to the exothermic reaction after contact. Moreover, during aging, the temperature rises due to the influence of outside air temperature. In addition to the increase in temperature, when the temperature is always controlled to 20 ° C by using a heat source such as hot water or ice water or a refrigerant, the aging time is compared. Regarding 20 ° C, since it is a temperature that is easy to handle throughout the year, it is set as such.

Further, in the laboratory experiment, the temperature can be easily adjusted up and down in order to make the conditions uniform. However, in the industrial production of synthetic rubber, since the raw material butadiene or the solvent is distilled and reused, the actual situation is usually Far more than 30 ° C temperature.

The present invention has been made in view of the above problems, and an object thereof is to provide a method for producing a high-quality and high-productivity diene rubber which can reduce the coloring over time by an industrially simple method and exhibits excellent activity. The diene rubber thus obtained.

The present inventors have made an effort to achieve the above object, and as a result, it has been found that the aging temperature is not kept at a low temperature because the energy for cooling is required, but the use of a refrigerant suppresses the accompanying heat generation reaction. The temperature rises and the temperature rises from the outside air temperature, and the temperature of the ripening reaction of the organoaluminum and the water is controlled at a low temperature of -30 to 17 ° C from the beginning to the end of the ripening, thereby suppressing impurities and organic aluminum contained in the raw material. By the side reaction, it is possible to suppress the formation of a substance which is a coloring matter of the time-dependent reaction product, and to promote the ripening reaction of water and the organic aluminum, thereby providing a high quality and high in reducing the coloration over time and exhibiting excellent activity. The production method of production, thereby completing the present invention.

That is, the present invention relates to a method for producing a diene-based rubber which is color-free, characterized in that it has the following steps: from the start of ripening to the polymerization of the diene monomer A step of maintaining the temperature range of -30 to 17 ° C until the end of aging, and aging the water with the organoaluminum.

Further, the present invention relates to a diene-based rubber which is obtained by the above-described production method and which is color-free.

As described above, according to the present invention, it is possible to provide a method for producing a high-quality, high-productivity and high-functionality diene rubber which can reduce the coloring over time by an industrially simple method and exhibits excellent activity. The diene rubber obtained.

The method for producing a diene rubber according to the present invention is preferably as follows: (A) a diene monomer is dissolved in (B) an organic solvent, (C) water is dissolved therein, and then (D1) an organoaluminum auxiliary contact is introduced. After the medium, (D2) aging the water and the organic aluminum at a temperature range of -30 to 17 ° C from the start of the aging to the end of the aging, and then (E) a transition metal catalyst is added to polymerize it, and after the polymerization, it is added ( F) a polymerization terminator and, if appropriate, (G) an antioxidant.

(A) diene monomer

Examples of the diene monomer include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, and 2-phenyl-1. 3-butadiene and the like. These may be used singly or in combination of two or more kinds, and may be used in combination with other diene such as 1,3-hexadiene. Among them, preferred is 1,3-butadiene.

The raw material diene monomer used in the present invention may also contain a polymerization inhibitor. As the polymerization inhibitor, a commonly used inhibitor can be used, and it is not particularly limited, and examples thereof include thiodiphenylamine, 4-t-butylcatechol, and 2,2-methylenebis-4-methyl. Base-6-tert-butylphenol, hydroquinone, o-nitrophenol, m-nitrophenol, p-nitrophenol, 2,4-dinitrophenol, 2,4,6-trinitrophenol, P-methoxyphenol, p-benzoquinone, thiophene , hydrazine, 2,6-di-t-butylhydroxytoluene, and the like.

Further, diethylhydroxylamine, dimethylhydroxylamine, methylethylhydroxylamine, dipropylhydroxylamine, dibutylhydroxylamine, dipentylhydroxylamine, selected from phosphoric acid, phosphonic acid, phosphinic acid, diphosphine A phosphoric acid compound, a dihydrogen phosphate compound, a dialkyl hydrogen phosphate compound, a trialkyl phosphate compound, or the like in an acid, a diphosphoric acid, a tripolyphosphoric acid, and a metaphosphoric acid can also be used as a polymerization inhibitor.

Of these, 4-tert-butylcatechol (abbreviated as TBC) is preferred.

(B) organic solvent

Examples of the organic solvent used in the present invention include aromatic hydrocarbons such as toluene, benzene, and xylene; aliphatic hydrocarbons such as n-hexane, butane, heptane, and pentane; cyclopentane, cyclohexane, and the like. Alicyclic hydrocarbons; olefinic hydrocarbons such as 1-butene, cis-2-butene, trans-2-butene; hydrocarbon-based solvents such as mineral spirits, solvent petroleum brain, kerosene; or halogenation such as dichloromethane A hydrocarbon solvent or the like. Further, 1,3-butadiene itself may be used as a polymerization solvent.

The solvent is preferably a non-aromatic hydrocarbon, and more preferably cyclohexane.

(C) water

In the present invention, the timing of adding water is to dissolve the (A) diene monomer in (B) the organic solvent, and it is important to balance the molar ratio of the (D1) organoaluminum auxiliary catalyst to the later input. .

(D1) The molar ratio of the organoaluminum co-catalyst to water (Al/H ₂ O) is preferably from 1 to 2.5, more preferably from 1.05 to 2.4, and particularly preferably from 1.1 to 2.3. (D1) If the molar ratio of the organoaluminum co-catalyst to water (Al/H ₂ O) is in the range of 1 to 2.5, it not only prevents coloration (change of yellowish brown color), but also prevents a significant decrease in polymerization activity. Therefore, the above Mobi ratio is also important in terms of productivity.

Productivity, if the polymerization of (D1) of water with an organoaluminum co-catalyst molar ratio (Al / H ₂ O) is less than 2.5 or greater than a rubber decreases, and prone to coloration (change of brown), therefore Poor.

(D1) organoaluminum auxiliary catalyst

In the present invention, as the organoaluminum auxiliary catalyst which can be used, there may be mentioned: a trialkyl aluminum, a dialkyl aluminum chloride, a dialkyl aluminum bromide, a sesqui aluminum alkyl chloride, and a half. Alkyl aluminum bromide, aluminum alkyl dichloride, and the like.

These organoaluminum auxiliary catalysts may be used alone or in combination of two or more. Particularly preferred among them are a trialkyl aluminum or a dialkyl aluminum chloride. When the two are used in combination, the effect of the present application can be particularly exerted, so that the trialkyl aluminum and the dialkyl aluminum chloride are preferably used together. And use.

Specific examples of the compound include trialkyl aluminum such as trimethyl aluminum, triethyl aluminum, triisobutyl aluminum, trihexyl aluminum, trioctyl aluminum, and tridecyl aluminum; dimethyl aluminum chloride; Dialkyl aluminum chloride such as diethyl aluminum chloride.

Further, it may contain an organoaluminum halide compound such as ethylaluminum sesquichloride or ethylaluminum dichloride; such as diethylaluminum hydride, diisobutylaluminum hydride or ethylaluminum sesquihydride Hydrogenated organoaluminum compounds.

(D2) ripening temperature of water and organoaluminum

The curing temperature of water and organic aluminum is -30 to 17 ° C, more preferably -15 to 15 ° C, and particularly preferably -10 to 10 ° C. When the aging temperature exceeds 17 ° C, the reaction between the organoaluminum and the impurities is promoted to form a cause of coloring over time. Further, the amount of alumoxane of the organic aluminum and water ripening reaction product which is the purpose of the original ripening is reduced to lower the activity. On the other hand, even if the temperature is lower than -30 ° C, the side reaction of the organoaluminum and the impurities is suppressed, and the coloring with time can be reduced, but it is industrially unfavorable to use the refrigerant to lower the temperature.

In general, the ripening of water and organoaluminum is an exothermic reaction. For example, even if it starts to mature at 10 ° C, it does not maintain 10 ° C and ends the ripening. Moreover, the aging temperature is also susceptible to an increase in temperature caused by the outside air temperature. However, since the energy for cooling is usually required, the aging temperature is not continuously controlled at a low temperature from the start to the end of the aging.

On the other hand, in the present invention, it is important to use a refrigerant to continuously control the aging temperature of water and organoaluminum at a low temperature from the start of ripening to the end of aging.

In the present invention, the aging start temperature is preferably -30 to 17 ° C, more preferably -20 to 15 ° C, and particularly preferably -15 to 10 ° C. Further, the curing end temperature is preferably -30 to 17 ° C, more preferably -20 to 15 ° C, and particularly preferably -15 to 10 ° C. The aging start temperature and the aging end temperature need not be the same. It is important to start aging at a temperature range of -30 to 17 ° C, to maintain a temperature range of -30 to 17 ° C for aging, and to finish aging at a temperature range of -30 to 17 ° C. When the secondary catalyst is aged in the temperature range as described above, a highly functional rubber having a reduced coloration over time and a high linear value can be produced.

In the present invention, the term "maturation" refers to a point in time at which (D1) organoaluminum is added to (C) an organic solvent in which water is dissolved, and the end of aging refers to a point in time at which (E) a transition metal catalyst is added.

In the method for producing a diene rubber according to the present invention, the (A) diene monomer is dissolved in the (B) organic solvent, and (C) water is dissolved therein, and then, if it is in a molar ratio to water. (Al/H ₂ O) is added to the (D1) organoaluminum auxiliary catalyst in a range of 1 to 2.5, and (D2) is maintained at a temperature range of -30 to 17 ° C from the start of ripening to the end of aging, and is set to (D3) After the aging time of 1 to 60 minutes, the (E) transition metal catalyst is charged and polymerized, which is more effective in producing a diene-based rubber which is colored without menstruation.

That is, by combining the conditions of the range of the (D1) organoaluminum auxiliary catalyst and the molar ratio of water (Al/H ₂ O), it is possible to further create a coloring prevention effect and high functionality.

(D3) ripening time of water and organoaluminum

Further, the ripening time of the water (D3) and the organic aluminum is preferably from 1 to 60 minutes, more preferably from 3 to 50 minutes, and most preferably from 5 to 45 minutes. If the aging time is shorter than 1 minute, the aluminoxane which is the product of the aging reaction cannot be sufficiently formed to promote the reaction of the unreacted organoaluminum with the impurities. If the aging time is longer than 60 minutes, there is a possibility that the unstable aluminum oxide cannot be continuously maintained. The alkane does not function in the polymerization reaction, and the polymer formed with respect to the catalyst is reduced, which tends to cause coloring.

(E) Transition metal catalyst

In the present invention, a cobalt-based catalyst can be mentioned as a transition metal catalyst that can be used.

As the cobalt-based catalyst, a salt of cobalt or a complex compound can be preferably used. Particularly preferred are cobalt chloride, cobalt bromide, cobalt nitrate, cobalt octoate (ethylhexanoate), cobalt naphthenate, cobalt acetate, cobalt malonate and the like; cobalt bisacetoacetate pyruvate Or an organic base complex such as triethylpyruvate, acetonitrile ethyl acetate, a cobalt salt pyridine complex or a pyridyl complex or an ethyl alcohol complex.

Especially preferred is cobalt octoate.

Further, the diene rubber of the present invention can be produced by a catalyst other than cobalt.

Examples of the catalyst other than the cobalt-based catalyst include a catalyst such as a nickel-based or a lanthanide-based catalyst.

Examples of the nickel-based catalyst include a catalyst system composed of a nickel compound-organoaluminum compound.

Further, examples of the nickel compound include organic acid salts such as nickel naphthenate, nickel formate, nickel octoate, nickel stearate, nickel citrate, nickel benzoate, and nickel formate; and organic compound compounds such as nickel acetonate; Nickel alkylbenzene sulfonate; nickel oxyborate.

Among them, nickel octoate is preferred.

Further, examples of the form of the diene polymer corresponding to the type of the metal catalyst include lithium catalyst polymerization-polybutadiene (Li-BR) and cobalt catalyst polymerization-polybutadiene (Co-BR). ), catalyst polymerization - polybutadiene (Nd-BR), nickel catalyst polymerization - polybutadiene (Ni-BR), titanium catalyst polymerization - polybutadiene (Ti-BR), styrene - Butadiene-block copolymer (SB, SBS, SEBS), random styrene-butadiene-copolymer (L-SBR), butadiene-isoprene-copolymer (BI), styrene - Butadiene-isoprene-terpolymer (SIB) and the like.

Among them, especially cobalt catalyst polymerization-polybutadiene (Co-BR) is most suitable in the method of the invention of the present application.

Further, in the present invention, a known molecular weight modifier such as a non-conjugated diene such as cyclooctadiene or propadiene or an α-olefin such as ethylene, propylene or 1-butene may be added during the polymerization. .

In the present invention, the polymerization temperature is preferably in the range of from -30 to 100 ° C, particularly preferably in the range of from 30 to 80 ° C. The polymerization time is preferably in the range of 5 minutes to 12 hours, and more preferably in the range of 10 minutes to 6 hours. In addition, regarding the polymerization pressure, it is about normal pressure or about 10 atmospheres (gauge pressure). It is carried out under pressure.

(F) polymerization terminator

The interruption of the polymerization of the diene rubber is carried out by a usual method by adding water, an alcohol, an organic acid or an inorganic acid and/or a phenol. With regard to the polymerization of the present invention, it is advantageous to use water to interrupt it in terms of cost.

In addition, as a polymerization terminator which is excellent in dispersibility, a water or a lower alcohol is used, and the ratio of use as water to the total raw material mixed solution is preferably 1.38 × 10 ^-8 to 9.9 vol%, more preferably It is 2.76 × 10 ^-8 ~ 5 vol%, and further preferably 4.14 × 10 ^-8 ~ 3 vol%. The total raw material mixed solution refers to the total amount of the diene monomer and the solvent as a raw material charged into the reactor.

The lower alcohol is preferably a carbon number of 5 or less, and specific examples thereof include methanol, ethanol, propanol, isopropanol, butanol, tert-butanol, pentanol, and the like. These may be used singly or in combination.

Further, in the present invention, after the (F) polymerization terminator is added, (G) an antioxidant may be added as needed, or the order of adding the (G) antioxidant and the (F) polymerization terminator may be reversed.

(G) antioxidant

Examples of the antioxidant include 4,6-bis(octylmethyl)-o-cresol, tert-butyl hydroquinone, dinitrochlorobenzene, hydroquinone, and water, dimethyl disulfide. An amine compound such as aminocarbamate, sodium polysulfide, polyethylene polyamine, diethylhydroxylamine or hydroxylamine; an oxime compound such as benzoquinone; sodium nitrate, sodium dithiocarbamate, and thiophene , 2,6-tert-butyl-4-methylphenol, and the like.

Among them, 4,6-bis(octylmethyl)-o-cresol is preferred.

The amount of the antioxidant to be added is preferably 8.256 × 10 ^-6 to 3.754 × 10 ^-4 mol per kg of the diene monomer. Since the antioxidant also reacts with the organoaluminum in the same manner as the impurities contained in the raw material, if the amount of the antioxidant added is more than 3.754×10 ^-4 , the coloration over time is deteriorated, and conversely, if it is far less At 8.256 × 10 ^-6 , deterioration is promoted and coloration is deteriorated.

The diene rubber produced by the present invention is characterized by low coloration over time and high linearity. Specifically, the value of ΔYI (YI (2 months) - YI (1 week)) is preferably 15 or less. The index of the linear value is expressed by the value of Tcp/ML. Generally, the higher the linear value, the higher the functionality such as wear resistance, high elastic modulus, and low loss, and it is preferable.

The timeless colored diene rubber produced by the present invention can also be used to manufacture all kinds of vulcanized rubber, such as tires, hoses, footwear components, industrial belts, medical rubber, sporting goods, crawlers. Or a gasket, and an impact-resistant modification of a polymer based on a vinyl aromatic compound such as polystyrene and an ABS-polymer manufactured by a bulk process.

[Examples]

Hereinafter, the present invention will be specifically described based on examples, but these do not limit the object of the present invention. First, the analysis method used in the examples is shown below.

(coloring measurement)

The judgment of coloring was quantitatively measured by a yellow index (YI value) by NDJ-300A manufactured by Nippon Denshoku Industries Co., Ltd. in addition to visual inspection.

(calculation of conversion rate)

When the raw material mixed solution (20% by weight of cyclohexane, 40% by weight of butadiene, and 40% by weight of butene) was 1 L, the specific gravity was 0.65, so the weight was 650 g. Weight 650g of butadiene monomer It is 40% by weight, so 650 x 0.4 = 260 g can be calculated.

After the polymerization reaction, for example, when 120 g of polybutadiene is obtained, 120 g / 260 g of ≒ 0.46 becomes a conversion rate of 46%.

(Mooney viscosity (ML ₁₊₄ , 100 ° C))

The measurement was performed in accordance with JIS K 6300.

(Toluene solution viscosity (Tcp))

After dissolving 2.28 g of the polymer in 50 ml of toluene, a standard solution for viscosity meter calibration (JIS Z 8809) was used as a standard solution, and a Cannon-Fenske viscometer No. 400 was used at 25 ° C. measuring.

(Toluene solution viscosity / Mui viscosity (Tcp/ML ₁₊₄ , 100 ° C))

It is an indicator of linearity. By linear is meant an indicator of the manner in which the molecular chains of the polymer expand. The higher the linear value is, the more it means a linear polymer, and the rubber having a high linear value is generally excellent in abrasion resistance, high elastic modulus, and low loss.

(Example 1)

The inside of the autoclave for polymerization having a content of 1.5 L was purged with nitrogen, and 1 L of a raw material mixed solution (20 wt% of cyclohexane, 40 wt% of butadiene, and 40 wt% of butene) was added and stirred. Then, 3.64 mmol of water was added and stirring was continued for 30 minutes at room temperature. Thereafter, after lowering to 10 ° C (aging start temperature), 3 mmol of diethylaluminum chloride (DEAC) and 1 mmol of triethylaluminum (TEA) were added, and the temperature was fixedly controlled at 10 ° C with ice water and hot water and stirred. It is matured in 15 minutes. The molar ratio of all organoaluminum catalyst (4 mmol/l) to water (Al/H ₂ O) was 1.10. Thereafter, 11 mmol of 1,5-cyclooctadiene (COD) was added as a molecular weight modifier, and the temperature of the solution was changed to 50° C., and 7.8 μmol of cobalt octoate (Co(Oct) ₂ ) was added to initiate polymerization, followed by polymerization for 30 minutes. After the reaction, 4,6-bis(octylmethyl)-o-cresol (cas number 110553-27-0) 0.2355 mmol was dissolved in an ethanol solution, and then added as an antioxidant, followed by stirring for 1 minute.

Thereafter, the recovered polybutadiene solution was vacuum dried at 100 ° C for 1 hour, thereby obtaining polybutadiene. The results are shown in Table 1. Further, the coloring measurement was carried out one week after the production, two weeks later, one month later, and two months later.

(Example 2)

After dissolving in water, after lowering to 10 ° C, 3 mmol of diethylaluminum chloride (DEAC) and 1 mmol of triethylaluminum (TEA) were added, and the temperature was fixedly controlled at 15 ° C with ice water and hot water and stirred for 15 minutes. Except for this, the operation was carried out in the same manner as in Example 1. The results are shown in Table 1.

(Example 3)

After dissolving in water, after lowering to 10 ° C, 3 mmol of diethylaluminum chloride (DEAC) and 1 mmol of triethylaluminum (TEA) were added, and the temperature was fixedly controlled at 17 ° C with ice water and hot water and stirred for 15 minutes. Except for this, the operation was carried out in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 1)

After dissolving in water, the temperature was lowered to 20 ° C, and 3 mmol of diethylaluminum chloride (DEAC) and 1 mmol of triethylaluminum (TEA) were added. The temperature was fixedly controlled at 20 ° C with ice water and hot water and stirred for 15 minutes. The operation was carried out in the same manner as in Example 1 except that the curing was carried out. The results are shown in Table 1.

(Comparative Example 2)

After dissolving in water, after reducing to 10 ° C, adding diethylaluminum chloride (DEAC) 3 mmol, Triethylaluminum (TEA) (1 mmol) was operated in the same manner as in Example 1 except that the temperature was fixedly controlled at 20 ° C with ice water and hot water and stirred for 15 minutes. The results are shown in Table 1.

(Example 4)

After dissolving in water, the temperature was lowered to 5 ° C, and 3 mmol of diethylaluminum chloride (DEAC) and 1 mmol of triethylaluminum (TEA) were added. The temperature was fixedly controlled at 5 ° C with ice water and hot water and stirred for 15 minutes. The operation was carried out in the same manner as in Example 1 except that the curing was carried out. The results are shown in Table 1.

(Example 5)

After dissolving in water, it was lowered to 5 ° C, and 3 mmol of diethylaluminum chloride (DEAC) and 1 mmol of triethylaluminum (TEA) were added. The temperature was fixedly controlled at 15 ° C with ice water and hot water and stirred for 15 minutes. The operation was carried out in the same manner as in Example 1 except that the curing was carried out. The results are shown in Table 1.

(Example 6)

After dissolving in water, it was lowered to 5 ° C, and 3 mmol of diethylaluminum chloride (DEAC) and 1 mmol of triethylaluminum (TEA) were added. The temperature was fixedly controlled at 17 ° C with ice water and hot water and stirred for 15 minutes. The operation was carried out in the same manner as in Example 1 except that the curing was carried out. The results are shown in Table 1.

(Example 7)

After being dissolved in water, after lowering to 5 ° C, 3 mmol of diethylaluminum chloride (DEAC) and 1 mmol of triethylaluminum (TEA) were added, and the temperature was controlled at -20 ° C with stirring of methanol water and hot water. Exercising in the same manner as in Example 1 except that it was aged for 15 minutes. Work. The results are shown in Table 1.

(Comparative Example 3)

After dissolving in water, it was lowered to 5 ° C, and 3 mmol of diethylaluminum chloride (DEAC) and 1 mmol of triethylaluminum (TEA) were added. The temperature was fixedly controlled at 20 ° C with ice water and hot water and stirred for 15 minutes. The operation was carried out in the same manner as in Example 1 except that the curing was carried out. The results are shown in Table 1.

(Example 8)

One half of the raw material mixed solution (20% by weight of cyclohexane, 40% by weight of butadiene, and 40% by weight of butene) was added and stirred. Then, 3.64 mmol of water was added and stirring was continued for 30 minutes at room temperature. Thereafter, after lowering to 10 ° C (maturation start temperature), 3 mmol of diethylaluminum chloride (DEAC) and 1 mmol of triethylaluminum (TEA) were added, and the temperature was fixedly controlled at 15 ° C with ice water and hot water and stirred. It is matured in 15 minutes. Thereafter, 500 ml of the remaining raw material mixed solution was fed. Except for this, the operation was carried out in the same manner as in the first embodiment. The results are shown in Table 1.

As is apparent from the results of Table 1, in Examples 1 to 3, compared with Comparative Examples 1 and 2, the coloration over time (the amount of change in YI with respect to the number of days passed) was low, and the conversion rate was also high. Further, it is understood that Examples 4 to 7 have higher linearity than Comparative Example 3.

Further, in Examples 4 to 7, compared with Comparative Example 3, the coloration over time (the amount of change in YI with respect to the number of days passed) was low, and the conversion rate was also high.

Further, it is also known that when the ripening concentration is set to 200% as in the case of Example 8, since the coloring over time (the amount of change with respect to the YI of the elapsed days) is low, the ripening concentration can be performed at 100%. Can be carried out at 200%. Further, by controlling the curing temperature, a highly functional (Tcp/ML) high-performance rubber can be produced. Examples 1 to 3 were linearly higher than Comparative Examples 1 and 2, and Examples 4 to 7 were linearly higher than Comparative Example 3.

(Example 9)

The inside of the autoclave for polymerization having a content of 1.5 L was purged with nitrogen, and 1 L of a raw material mixed solution (20 wt% of cyclohexane, 40 wt% of butadiene, and 40 wt% of butene) was added and stirred. Then, 2.67 mmol of water was added and stirring was continued for 30 minutes at room temperature. Thereafter, after lowering to 10 ° C (aging start temperature), 3 mmol of diethylaluminum chloride (DEAC) and 1 mmol of triethylaluminum (TEA) were added, and the temperature was fixedly controlled at 10 ° C with ice water and hot water and stirred. It is matured in 15 minutes. The molar ratio of all organoaluminum catalyst (4 mmol/l) to water (Al/H ₂ O) was 1.5. Thereafter, 11 mmol of 1,5-cyclooctadiene (COD) was added as a molecular weight modifier, and the temperature of the solution was changed to 50° C., and 7.8 μmol of cobalt octoate (Co(Oct) ₂ ) was added to initiate polymerization, followed by polymerization for 30 minutes. After the reaction, 4,6-bis(octylmethyl)-o-cresol (cas number 110553-27-0) 0.2355 mmol was dissolved in an ethanol solution, and then added as an antioxidant, and stirred for 1 minute. The results are shown in Table 2.

(Embodiment 10)

The inside of the autoclave for polymerization having a content of 1.5 L was purged with nitrogen, and 1 L of a raw material mixed solution (25 wt% of cyclohexane, 38 wt% of butadiene, and 37 wt% of butene) was added and stirred. Then, 1.50 mmol of water was added and stirring was continued for 30 minutes at room temperature. Thereafter, after lowering to 10 ° C (aging start temperature), 2.7 mmol of diethylaluminum chloride (DEAC) and 0.3 mmol of triethylaluminum (TEA) were added, and the temperature was fixedly controlled at 10 ° C by using ice water and hot water. It was stirred for 15 minutes to be aged. The molar ratio of all organoaluminum catalyst (3 mmol/l) to water (Al/H ₂ O) was 2.0. Thereafter, 10.5 mmol of 1,5-cyclooctadiene (COD) was added as a molecular weight modifier, the temperature of the solution was set to 50 ° C, and cobalt octoate (Co(Oct) ₂ ) was added in an amount of 11.7 μmol to start polymerization, and 30 minutes was started. polymerization. After the reaction, 4,6-bis(octylmethyl)-o-cresol (cas number 110553-27-0) 0.2355 mmol was added and dissolved in an ethanol solution, and then added as an antioxidant, followed by stirring for 1 minute. The results are shown in Table 2.

(Example 11)

The inside of the autoclave for polymerization having a content of 1.5 L was purged with nitrogen, and 1 L of a raw material mixed solution (30 wt% of cyclohexane, 35 wt% of butadiene, and 35 wt% of butene) was added and stirred. Then, 1.20 mmol of water was added and stirring was continued for 30 minutes at room temperature. Thereafter, after lowering to 10 ° C (aging start temperature), 2.7 mmol of diethylaluminum chloride (DEAC) and 0.3 mmol of triethylaluminum (TEA) were added, and the temperature was fixedly controlled at 10 ° C by using ice water and hot water. It was stirred for 15 minutes to be aged. The molar ratio of all organoaluminum catalyst (3 mmol/l) to water (Al/H ₂ O) was 2.5. Thereafter, 10 mmol of 1,5-cyclooctadiene (COD) was added as a molecular weight modifier, the temperature of the solution was set to 50 ° C, and cobalt (Co(Oct) ₂ ) 23.4 μmol was added to start polymerization, and polymerization was carried out for 30 minutes. After the reaction, 4,6-bis(octylmethyl)-o-cresol (cas number 110553-27-0) 0.2355 mmol was dissolved in an ethanol solution, and then added as an antioxidant, and stirred for 1 minute. The results are shown in Table 2.

As is apparent from the results of Tables 1 and 2, in Example 1 and Examples 9 to 11, compared with Comparative Example 2, the coloration over time (ΔYI) was low, and the conversion ratio was also high.

Based on the above, Table 1 is a comparison between Al/H of 1.1 in the system of trialkylaluminum and dialkylaluminum chloride. Table 2 shows that Al/H is 2.2 in the system of dialkylaluminum chloride alone. Time comparison. Under any of the conditions, the aging temperature was maintained below 17 ° C from the start of the ripening to the end, and a significant improvement effect was obtained in terms of ΔYI and conversion and linearity improvement.

Further, regarding the improvement value of ΔYI in the case of being 17 ° C or lower, the combined system of trialkyl aluminum and dialkyl aluminum chloride is larger. When the system was used in combination, ΔYI = 18.4 of Comparative Example 2, ΔYI = 11.7 of Example 1, and the improvement value was 6.7.

As described above, as an improvement value of ΔYI, a combined system of trialkyl aluminum and dialkyl aluminum chloride The effect is large, and the combined system of trialkyl aluminum and dialkyl aluminum chloride has a great advantage in the present application because the absolute value of the degree of coloration is large.

Claims (1)

A method for producing a diene rubber, which comprises the steps of maintaining a temperature range of -30 to 17 ° C from the start of the ripening to the end of the aging before the polymerization of the diene monomer, and the water and diethyl aluminum chloride And triethylaluminum is aged for 5 to 60 minutes, and the molar ratio of aluminum diethylaluminum chloride and triethylaluminum to water (Al/H ₂ O) is 1 to 2.5.