KR102562930B1 - Method for producing diene-based rubber that is not colored over time and diene-based rubber obtained thereby - Google Patents

Abstract

Provided is an industrially simple method for producing a high-quality and highly productive diene-based rubber that can reduce discoloration with time, exhibit high functionality, and exhibit excellent activity, and a diene-based rubber obtained thereby.
In a method for producing a diene rubber, a step of aging water and organoaluminium by maintaining a temperature range of -30 to 17 ° C. from the start of aging to the end of aging before polymerizing the diene monomer It is a method for producing a non-colored diene rubber.

Description

Method for producing diene-based rubber that is not colored over time and diene-based rubber obtained thereby

The present invention relates to a method for producing a diene rubber that does not discolor with time, and a diene rubber obtained thereby, preventing discoloration occurring in conventional diene rubber.

Usually, many compounds, such as various catalysts, cocatalysts, and stabilizers, are often added to diene-based rubber in the manufacturing process. In particular, since stability of the product is achieved by adding a stabilizer, such an additive is essential. However, when the type or amount of the additive is large, side effects such as coloring or odor often occur, and unexpected problems may occur.

In particular, when coloration occurs, it often becomes a big problem for applications requiring transparency of the product or applications in which it is desired to color the product in a desired color, and many solutions have been sought so far.

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

Further, in Patent Literature 2, after polymerization of butadiene rubber, one or more phenolic compounds are mixed, and the pH value is adjusted to be in the range of 4 to 11 and the oxygen content to be 0 to 0.3 ppm, thereby obtaining a stable and colorless product. Polybutadiene rubber is provided.

Further, in Prior Document 3, during polymerization of a polymer, by adding at least one compound selected from the group consisting of an arylphosphine compound and a silazane compound externally to a combination comprising an antioxidant or a polymerization inhibitor. , to prevent discoloration.

However, it is difficult to say that any coloration prevention method is necessarily superior in terms of cost, for example, in many cases, a compound is added to the additives used in the conventional manufacturing process, and the manufacturing process becomes more complicated.

Then, as shown in Patent Document 4, the present inventors performed coloring improvement by controlling the ratio of organoaluminum and antioxidant. Furthermore, as shown in Patent Document 5, a manufacturing method excellent in coloration over time has been invented by optimizing the aging time of organoaluminum and water.

Patent Document 1: Japanese Unexamined Patent Publication No. Heisei 06-345832 Patent Document 2: Japanese Patent Publication No. 2003-535926 Patent Document 3: Japanese Unexamined Patent Publication No. 2009-249308 Patent Document 4: Japanese Unexamined Patent Publication No. 2011-195632 Patent Document 5: Japanese Unexamined Patent Publication No. 2011-201972

The inventors of the present invention have been reducing coloration with time by the methods of Patent Literatures 4 and 5, but there is a situation where further improvement is required. In the studies so far, in order to compare the experimental conditions under constant conditions, the aging temperature was made uniform at 20 ° C., and then the comparison was performed by changing the aging time. For example, in Example 1 of Patent Document 5, organoaluminum was added after water was added to the raw material mixture solution, stirred and dissolved, and then lowered to 10°C. Organic aluminum and water generate a temperature rise by an exothermic reaction after contact. In addition, during aging, a temperature rise occurs due to the influence of outside air temperature. In addition to these temperature rises, comparison of aging times has been performed under constant control at 20°C by using a heat source such as hot water or ice water and a refrigerant. This 20°C was set because it is a temperature that is easy to keep the same throughout the year.

Also, in laboratory experiments, the temperature can be simply raised and lowered to match the conditions, but in plants producing synthetic rubber industrially, raw material butadiene and solvents are distilled and reused, so it is usually well within 30 The actual situation is that the temperature is such that it exceeds °C.

The present invention has been made in view of the above problems, and is an industrially simple method, reducing discoloration with time and exhibiting excellent activity, a method for producing a high-quality and highly productive diene-based rubber, and a diene-based rubber obtained thereby intended to provide

As a result of intensive studies to achieve the above object, the inventors of the present invention have so far not kept the aging temperature at a low temperature because energy for cooling is required. The temperature rise is suppressed using a refrigerant, and the temperature of the aging reaction between organic aluminum and water is controlled from the beginning to the end of aging at a low temperature such as -30 to 17 ° C. and thereby suppressing the generation of a substance that causes coloration with time as a side reaction product, while promoting the aging reaction of water and organoaluminum, reducing coloration with time and exhibiting excellent activity, high-quality and high-productivity production It was discovered that a method could be provided, and the present invention was reached.

That is, the present invention is a method for producing a diene-based rubber, comprising a step of aging water and organic aluminum by maintaining a temperature range of -30 to 17 ° C. from the start of aging to the end of aging before polymerizing the diene-based monomer. It relates to a method for producing a diene-based rubber that is not colored over time.

Furthermore, the present invention relates to a diene-based rubber obtained by the above production method that is not colored over time.

As described above, according to the present invention, a method for producing a high-quality, highly productive, and highly functional diene-based rubber that reduces discoloration with time and exhibits excellent activity by an industrially simple method, and a diene-based rubber obtained thereby can provide.

In the method for producing a diene rubber of the present invention, (A) a diene monomer is dissolved in (B) an organic solvent, (C) water is dissolved therein, and then (D1) an organic aluminum cocatalyst is added, After aging the water and organic aluminum by maintaining the temperature range of -30 ~ 17 ℃ from the start of aging to the end of aging (D2), (E) polymerization by adding a transition metal catalyst, and after polymerization, (F) termination of polymerization It is preferable to add an antioxidant and, in some cases, (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. These may be used individually by 1 type, may mix 2 or more types, and may also be used copolymerized with other dienes, such as 1, 3- hexadiene. Among them, 1,3-butadiene is preferred.

The raw material diene-based monomer used in the present invention may also contain a polymerization inhibitor. As the polymerization inhibitor, commonly used inhibitors can be used and are not particularly limited. sherry butylphenol, hydroquinone, o-nitrophenol, m-nitrophenol, p-nitrophenol, 2,4-dinitrophenol, 2,4,6-trinitrophenol, p-methoxyphenol, p-benzoquinone, phenothiazine, anthraquinone, 2,6-di-t-butylhydroxytoluene, and the like.

In addition, diethylhydroxylamine, dimethylhydroxylamine, methylethylhydroxylamine, dipropylhydroxylamine, dibutylhydroxylamine, dipentylhydroxylamine, phosphoric acid, phosphonic acid, phosphinic acid, diphosphonic acid, Phosphoric acid compounds selected from phosphoric acid, tripolyphosphoric acid and metaphosphoric acid, dihydrogenphosphate alkyl ester compounds, hydrogen phosphate dialkyl ester compounds, and phosphoric acid trialkyl ester compounds can also be used as polymerization inhibitors.

Among these, 4-tertiary butyl catechol (abbreviated as TBC) is particularly preferable.

(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, alicyclic hydrocarbons such as cyclopentane and cyclohexane, 1-butene, olefinic hydrocarbons such as cis-2-butene and trans-2-butene, mineral spirits, hydrocarbon solvents such as solvent naphtha and kerosene, halogenated hydrocarbon solvents such as methylene chloride, and the like. Also, 1,3-butadiene itself may be used as a polymerization solvent.

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

(C) water

In the present invention, the timing for adding water is after dissolving the diene monomer (A) in the organic solvent (B), and the balance of the molar ratio with the organic aluminum cocatalyst (D1) added thereafter becomes important.

(D1) The molar ratio of the organic aluminum cocatalyst to water (Al/H ₂ O) is preferably 1 to 2.5, more preferably 1.05 to 2.4, and particularly preferably 1.1 to 2.3. (D1) When the molar ratio of the organoaluminum cocatalyst to water (Al/H ₂ O) is in the range of 1 to 2.5, it is possible to prevent not only color development (change in yellowish brown color), but also a significant decrease in polymerization activity. Therefore, the molar ratio is important also in terms of productivity.

(D1) When the molar ratio of the organoaluminum cocatalyst to water (Al/H ₂ O) is less than 1 or greater than 2.5, the productivity of the rubber to be polymerized decreases and color development (change in yellowish brown) tends to occur, which is preferable. don't

(D1) organic aluminum promoter

Examples of the organic aluminum cocatalyst usable in the present invention include trialkyl aluminum, dialkyl aluminum chloride, dialkyl aluminum bromide, alkyl aluminum sesquichloride, alkyl aluminum sesqui bromide, and alkyl aluminum dichloride.

One type of these organoaluminum cocatalysts may be used, or two or more types may be used together. Among them, trialkyl aluminum and dialkyl aluminum chloride are particularly preferable, and when both are used in combination, the effect of the present application can be exhibited, so it is more preferable to use trialkyl aluminum and dialkyl aluminum chloride in combination.

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

In addition, organic aluminum halide compounds such as sesquiethyl aluminum chloride and ethyl aluminum dichloride; Hydrogenated organoaluminum compounds such as diethylaluminum hydride, diisobutylaluminum hydride and sesquiethylaluminum hydride are also included.

(D2) aging temperature of water and organic aluminum

The aging 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 organoaluminum and impurities proceeds, and substances that cause coloration with time are generated. In addition, the amount of alumoxane, which is a aging reaction product of organoaluminum and water, which is the original purpose of aging, decreases, thereby lowering the activity. On the other hand, even if the temperature is lower than -30 ° C., it is possible to suppress side reactions between organic aluminum and impurities and reduce coloration with time, but it is industrially undesirable to lower the temperature to that temperature using a refrigerant.

In general, aging of water and organic aluminum is an exothermic reaction, and even if aging is initiated at, for example, 10°C, aging does not end while maintaining 10°C. In addition, the aging temperature is also easily affected by a temperature increase or the like due to outside air temperature. However, since energy for cooling is usually required, continuous control of the aging temperature at a low temperature from the start of aging to the end is not performed.

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

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. The aging 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 do not have to be the same, and the aging starts in the temperature range of -30 to 17 ° C, the aging is performed while maintaining the temperature range of -30 to 17 ° C, and the temperature is -30 to 17 ° C. It is important that aging ends in the range. When the cocatalyst is aged in the above temperature range, it is possible to produce a highly functional rubber having a low coloration with time and a high linearity value.

In the present invention, the start of aging refers to the time when (D1) organic aluminum is added to the organic solvent in which water is dissolved (C), and the end of aging refers to the time when (E) the transition metal catalyst is added.

In the method for producing a diene rubber of the present invention, (A) a diene monomer is dissolved in (B) an organic solvent, (C) water is dissolved therein, and then (D1) an organic aluminum cocatalyst is dissolved in water and The molar ratio (Al/H ₂ O) is added so that it is in the range of 1 to 2.5, (D2) maintaining the temperature range of -30 to 17 ℃ from the start of aging to the end of aging, (D3) 1 to 60 minutes After aging, polymerization by adding (E) a transition metal catalyst is more effective in producing a diene-based rubber that is not colored over time.

That is, (D1) By using together the conditions limiting the range of the molar ratio of the organoaluminum cocatalyst and water (Al/H ₂ O), a further discoloration prevention effect and high functionality are created.

(D3) aging time of water and organic aluminum

The aging time between water and (D3) organoaluminum is particularly preferably 1 to 60 minutes, more preferably 3 to 50 minutes, and most preferably 5 to 45 minutes. If the aging time is shorter than 1 minute, alumoxane, the aging reaction product, cannot be sufficiently formed, and the reaction between unreacted organoaluminum and impurities proceeds. If the aging time is longer than 60 minutes, unstable alumoxane can be maintained continuously. It does not work in the polymerization reaction, and the polymer produced per catalyst decreases, which tends to cause coloration.

(E) transition metal catalyst

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

As the cobalt-based catalyst, salts and complexes of cobalt are preferably used. Particularly preferred are cobalt salts such as cobalt chloride, cobalt bromide, cobalt nitrate, cobalt octylate (ethylhexanoate), cobalt naphthenate, cobalt acetate, and cobalt malonate; organic base complexes such as bisacetylacetonate and trisacetylacetonate of cobalt, ethyl acetoacetate ester cobalt, and pyridine complexes and picoline complexes of cobalt salts; and ethyl alcohol complexes.

Among these, cobalt octylate is particularly preferable.

In addition, the diene rubber of the present invention can be produced with a catalyst other than cobalt.

Catalysts other than cobalt-based catalysts include nickel-based catalysts and neodymium-based catalysts.

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

Examples of the nickel compound include organic acid salts such as nickel naphthenate, nickel formate, nickel octylate, nickel stearate, nickel citrate, nickel benzoate, and nickel toluate; organic complex compounds such as nickel acetylacetonate; nickel benzene sulfonate; Nickel oxyborate etc. are mentioned.

Among these, nickel octylate is preferable.

In addition, as a form of diene-based polymer according to the type of metal catalyst, lithium catalyst polymerization-polybutadiene (Li-BR), cobalt catalyst polymerization-polybutadiene (Co-BR), neodymium catalyst polymerization-polybutadiene (Nd-BR) , nickel-catalyzed polymerization-polybutadiene (Ni-BR), titanium-catalyzed polymerization-polybutadiene (Ti-BR), styrene-butadiene-block copolymers (SB, SBS, SEBS), random styrene-butadiene-copolymers (L- SBR), butadiene-isoprene-copolymer (BI), styrene-butadiene-isoprene-terpolymer (SIB), and the like.

Among them, cobalt-catalyzed polymerization-polybutadiene (Co-BR) is optimal in the method of the present invention.

Further, in the present invention, a known molecular weight modifier, for example, non-conjugated dienes such as cyclooctadiene and allene, or α-olefins such as ethylene, propylene and butene-1 may be added during polymerization.

In the present invention, the polymerization temperature is preferably in the range of -30 to 100°C, particularly preferably in the range of 30 to 80°C. The polymerization time is preferably in the range of 5 minutes to 12 hours, and particularly preferably in the range of 10 minutes to 6 hours. In addition, the polymerization pressure is performed under normal pressure or a pressure up to about 10 atm (gauge pressure).

(F) polymerization terminator

The polymerization of diene rubber is stopped in a conventional manner by adding water, alcohol, organic or inorganic acid and/or phenol. The polymerization according to the present invention is advantageous from the point of view of cost to be stopped with water.

Among these, water and lower alcohols are preferred as polymerization terminator with good dispersibility ^. , more preferably 2.76×10 ^-8 to 5 vol%, and still more preferably 4.14×10 ^-8 to 3 vol%. The total raw material mixed solution is the total amount of the diene-based monomer and the solvent as raw materials put into the reactor.

The lower alcohol preferably has 5 or less carbon atoms, and specifically includes methanol, ethanol, propanol, isopropanol, butanol, tert-butyl alcohol, pentanol and isomers thereof. These may be used independently or may be mixed and used.

In the present invention, after the polymerization terminator (F), the antioxidant (G) may be added as necessary, but the order of adding the antioxidant (G) and the polymerization terminator (F) may be reversed.

(G) antioxidants

As antioxidants, 4,6-bis (octylmethyl) -o-cresol, tertiary butyl hydroquinone, dinitrochlorobenzene, hydroquinone and water, dimethyl dithiocarbamate, sodium polysulfide, polyethylene polyamine, di amine compounds such as ethylhydroxylamine and hydroxylamine, quinone compounds such as benzoquinone, sodium nitrate, sodium dithiocarbamate, phenothiazine, 2,6-t-butyl-4-methylphenol, etc. can

Among these, 4,6-bis (octylmethyl) -o-cresol is preferable.

The added amount of the antioxidant is preferably 8.256×10 ^-6 to 3.754×10 ^-4 moles per 1 mole of the diene monomer. Since antioxidants also react with organoaluminum in the same way as impurities contained in raw materials, when the amount of antioxidants added is greater than 3.754 × 10 ^-4 , coloration over time is poor, and conversely, when the amount is too less than 8.256 × 10 ^-6 , deterioration occurs. progresses, leading to deterioration of coloring.

The diene-based rubber produced by the present invention is characterized by low discoloration over time and high linearity. Specifically, it is preferable that the value of ΔYI (YI (2 months) - YI (1 week)) is 15 or less. As an index of the linearity value, it is represented by a value of Tcp/ML, but in general, the higher the linearity value, the higher the functionality such as abrasion resistance, high modulus of elasticity, and low loss can be expressed, so it is preferable.

The diene-based rubber produced by the present invention, which is not colored over time, is used for producing all kinds of vulcanizates, such as tires, hoses, shoe parts, industrial belts, medical rubbers, sporting goods, crawlers or packings. , and for modifying the impact resistance of polymers based on vinyl aromatic compounds, such as polystyrene and ABS-polymers prepared by the bulk method.

Example

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

(coloration measurement)

Coloration was judged quantitatively by yellow index (YI value) by NDJ-300A manufactured by Nippon Denshoku Kogyo Co., Ltd. in addition to visual observation.

(Calculation of Conversion Rate)

In the case of 1 L of the raw material mixed solution (cyclohexane 20 wt%, butadiene 40 wt%, butene 40 wt%), the weight is 650 g because the specific gravity is 0.65. Since the butadiene monomer is 40 wt% in the weight of 650 g, it can be calculated as 650 × 0.4 = 260 g.

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

(Mooney viscosity (ML ₁₊₄ , 100℃))

It was measured based on JIS K 6300.

(Toluene solution viscosity (Tcp))

After dissolving 2.28 g of the polymer in 50 ml of toluene, measurement was performed at 25°C using a standard solution for calibrating a viscometer (JIS Z 8809) as a standard solution and using a Canon Penske viscometer No.400.

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

It is an indicator of linearity. Linearity is an index of how the molecular chain of a polymer expands.

A higher linearity value means a linear polymer, and rubber with a higher linearity value is generally said to be superior in abrasion resistance, high modulus of elasticity, and low loss.

(Example 1)

The interior of an autoclave for polymerization with a net weight of 1.5 L was purged with nitrogen, and 1 L of a mixed solution of raw materials (cyclohexane 20 wt%, butadiene 40 wt%, butene 40 wt%) was put thereinto and stirred. Subsequently, 3.64 mmol of water was added, and stirring was continued for 30 minutes at room temperature. Then, after lowering to 10 ° C (aging start temperature), 3 mmol of diethyl aluminum chloride (DEAC) and 1 mmol of triethyl aluminum (TEA) were added, and the temperature was constantly controlled at 10 ° C with ice water and hot water to 15 It was aged by stirring for a minute. The molar ratio of the total organic aluminum catalyst (4 mmol/l) to water (Al/H ₂ O) is 1.10. After that, 11 mmol of 1,5-cyclooctadiene (COD) was added as a molecular weight modifier, the temperature of the solution was set to 50° C., 7.8 μmol of cobalt octylate (Co(Oct) ₂ ) was added, and polymerization was initiated. , polymerization was carried out for 30 minutes. After the reaction, 0.2355 mmol of 4,6-bis(octylmethyl)-o-cresol (cas-number 110553-27-0) was added as an ethanol solution as an antioxidant, and the mixture was stirred for 1 minute.

Then, polybutadiene was obtained by vacuum-drying the solvent from the collect|recovered polybutadiene solution at 100 degreeC for 1 hour. The results are shown in Table 1. On the other hand, coloration measurement was performed after 1 week, 2 weeks, 1 month, and 2 months after production.

(Example 2)

After dissolving in water, lowering the temperature to 10 ° C, adding 3 mmol of diethyl aluminum chloride (DEAC) and 1 mmol of triethyl aluminum (TEA), controlling the temperature with ice water and hot water at 15 ° C, and stirring for 15 minutes to mature It was carried out in the same manner as in Example 1 except that it was made. The results are shown in Table 1.

(Example 3)

After dissolving in water, lowering the temperature to 10 ° C, adding 3 mmol of diethyl aluminum chloride (DEAC) and 1 mmol of triethyl aluminum (TEA), controlling the temperature with ice water and hot water at 17 ° C, and stirring for 15 minutes to mature It was carried out in the same manner as in Example 1 except that it was made. The results are shown in Table 1.

(Comparative Example 1)

After dissolving in water, the temperature was lowered to 20 ° C, 3 mmol of diethyl aluminum chloride (DEAC) and 1 mmol of triethyl aluminum (TEA) were added, and the temperature was constantly controlled with ice water and hot water at 20 ° C and stirred for 15 minutes to mature Except for that, it was carried out in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 2)

After dissolving in water, lowering the temperature to 10 ° C, adding 3 mmol of diethyl aluminum chloride (DEAC) and 1 mmol of triethyl aluminum (TEA), controlling the temperature with ice water and hot water at 20 ° C, and stirring for 15 minutes to mature It was carried out in the same manner as in Example 1 except that it was made. The results are shown in Table 1.

(Example 4)

After dissolving in water, the temperature was lowered to 5 ° C, 3 mmol of diethyl aluminum chloride (DEAC) and 1 mmol of triethyl aluminum (TEA) were added, the temperature was constantly controlled with ice water and hot water at 5 ° C, and the mixture was stirred for 15 minutes to mature Except for that, it was carried out in the same manner as in Example 1. The results are shown in Table 1.

(Example 5)

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

(Example 6)

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

(Example 7)

After dissolving in water, lowering the temperature to 5°C, adding 3 mmol of diethylaluminum chloride (DEAC) and 1 mmol of triethylaluminum (TEA), controlling the temperature to -20°C with cooled methanol water and hot water It was carried out in the same manner as in Example 1 except that the mixture was aged by stirring for 15 minutes. The results are shown in Table 1.

(Comparative Example 3)

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

(Example 8)

A half amount of 500 mL of the raw material mixture solution (20 wt% of cyclohexane, 40 wt% of butadiene, and 40 wt% of butene) was added and stirred. Subsequently, 3.64 mmol of water was added, and stirring was continued for 30 minutes at room temperature. Thereafter, after lowering the temperature to 10°C (aging start temperature), 3 mmol of diethylaluminum chloride (DEAC) and 1 mmol of triethylaluminum (TEA) were added, and the temperature was constantly controlled at 15°C with ice water and hot water to 15°C. It was aged by stirring for a minute. After that, 500 mL of the remaining raw material mixture solution was introduced. Other than that, it carried out by carrying out similarly to Example 1. The results are shown in Table 1.

Total Al/H ^(*) : means the molar ratio of the total organoaluminum catalyst and water.

ΔYI ^(**) : YI (2 months) - YI (1 week) value.

From the results in Table 1, it can be seen that Examples 1 to 3 have lower discoloration (change in YI per number of elapsed days) and higher conversion rates than Comparative Examples 1 and 2. Moreover, it turns out that Examples 4-7 have high linearity compared with Comparative Example 3.

In addition, it can be seen that Examples 4 to 7 are lower in coloration with time (change in YI per number of elapsed days) than Comparative Example 3, and also have high conversion rates.

Further, as in Example 8, even when the aging concentration was set to 200%, it was found that the aging concentration may be set to 100% or 200% because the coloration over time (change in YI per number of elapsed days) is low. could In addition, high-performance rubber with high linearity (Tcp/ML) can be produced by controlling the aging temperature. Examples 1 to 3 have higher linearity than Comparative Examples 1 and 2, and Examples 4 to 7 have higher linearity than Comparative Example 3.

(Example 9)

The interior of an autoclave for polymerization with a net weight of 1.5 L was purged with nitrogen, and 1 L of a mixed solution of raw materials (cyclohexane 20 wt%, butadiene 40 wt%, butene 40 wt%) was put thereinto and stirred. Subsequently, 2.67 mmol of water was added, and stirring was continued for 30 minutes at room temperature. Then, after lowering to 10 ° C (aging start temperature), 3 mmol of diethyl aluminum chloride (DEAC) and 1 mmol of triethyl aluminum (TEA) were added, and the temperature was constantly controlled at 10 ° C with ice water and hot water to 15 It was aged by stirring for a minute. The molar ratio of the total organic aluminum catalyst (4 mmol/l) to water (Al/H ₂ O) is 1.5. After that, 11 mmol of 1,5-cyclooctadiene (COD) was added as a molecular weight modifier, the temperature of the solution was set to 50° C., 7.8 μmol of cobalt octylate (Co(Oct) ₂ ) was added, and polymerization was initiated. , polymerization was carried out for 30 minutes. After the reaction, 0.2355 mmol of 4,6-bis(octylmethyl)-o-cresol (cas-number 110553-27-0) was added as an ethanol solution as an antioxidant, and the mixture was stirred for 1 minute. The results are shown in Table 2.

(Example 10)

The interior of an autoclave for polymerization with a net weight of 1.5 L was purged with nitrogen, and 1 L of a mixed solution of raw materials (cyclohexane 25 wt%, butadiene 38 wt%, butene 37 wt%) was added and stirred. Subsequently, 1.50 mmol of water was added, and stirring was continued for 30 minutes at room temperature. Then, after lowering to 10 ° C. (aging start temperature), 2.7 mmol of diethyl aluminum chloride (DEAC) and 0.3 mmol of triethyl aluminum (TEA) were added, and the temperature was constantly controlled at 10 ° C. with ice water and hot water to reach 15 It was aged by stirring for a minute. The molar ratio of the total organic aluminum catalyst (3 mmol/l) to water (Al/H ₂ O) is 2.0. Then, 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., 11.7 μmol of cobalt octylate (Co(Oct) ₂ ) was added, and polymerization was initiated. , polymerization was carried out for 30 minutes. After the reaction, 0.2355 mmol of 4,6-bis(octylmethyl)-o-cresol (cas-number 110553-27-0) was added as an ethanol solution as an antioxidant, and the mixture was stirred for 1 minute. The results are shown in Table 2.

(Example 11)

The inside of an autoclave for polymerization having a net weight of 1.5 L was purged with nitrogen, and 1 L of a mixed solution of raw materials (cyclohexane 30 wt%, butadiene 35 wt%, butene 35 wt%) was put thereinto and stirred. Subsequently, 1.20 mmol of water was added, and stirring was continued for 30 minutes at room temperature. Then, after lowering to 10 ° C. (aging start temperature), 2.7 mmol of diethyl aluminum chloride (DEAC) and 0.3 mmol of triethyl aluminum (TEA) were added, and the temperature was constantly controlled at 10 ° C. with ice water and hot water to reach 15 It was aged by stirring for a minute. The molar ratio of the total organic aluminum catalyst (3 mmol/l) to water (Al/H ₂ O) is 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., 23.4 μmol of cobalt octylate (Co(Oct) ₂ ) was added, and polymerization was initiated. , polymerization was carried out for 30 minutes. After the reaction, 0.2355 mmol of 4,6-bis(octylmethyl)-o-cresol (cas-number 110553-27-0) was added as an ethanol solution as an antioxidant, and the mixture was stirred for 1 minute. The results are shown in Table 2.

From the results of Table 1 and Table 2, it can be seen that Example 1 and Examples 9 to 11 have a low coloration over time (ΔYI) and a high conversion rate as compared with Comparative Example 2.

From the above, Table 1 is a comparison of Al/H at 1.1 in the combined use system of trialkyl aluminum and dialkyl aluminum chloride, and Table 2 is a comparison at Al / H of 2.2 in the dialkyl aluminum chloride single system. Under any conditions, by maintaining the aging temperature at 17° C. or less from the start of aging to the end, surprising effects of improvement in ΔYI, conversion, and linearity were obtained.

On the other hand, the improved value of ΔYI at 17°C or lower is greater for the combined use system of trialkyl aluminum and dialkyl aluminum chloride. In the case of the combination system, ΔYI = 11.7 in Example 1 compared to ΔYI = 18.4 in Comparative Example 2, and the improvement value is 6.7.

As described above, as the improvement value of ΔYI, the combined use system of trialkyl aluminum and dialkyl aluminum chloride has a greater effect, and the combined use system of trialkyl aluminum and dialkyl aluminum chloride has a larger absolute value of coloration. , the improvement merit in this application is great.

Claims (5)

In the method for producing a diene rubber,
Before polymerizing the diene monomer, it has a step of aging water, diethyl aluminum chloride and triethyl aluminum for 5 to 60 minutes,
By cooling to maintain the temperature range of -30 to 17 ° C. from the start of aging to the end of aging, side reactions between diethyl aluminum chloride and triethyl aluminum and impurities are suppressed,
A method for producing a diene-based rubber, characterized in that the molar ratio of diethyl aluminum chloride and triethyl aluminum to water (Al / H ₂ O) is 1 to 2.5. delete delete delete delete