JPS59176311A - Production of polybutadiene - Google Patents

Abstract

PURPOSE:To produce polybutadiene excellent in processability and resilience, by bringing a mixture of a hydrocarbon solvent wirh 1,3-butadiene into contact with an organolithium compound by mixing in the presence of a trivial amount of an ether compound and a trivial amount of 1,2-butadiene and polymerizing the product at a high temperature. CONSTITUTION:A mixture of a hydrocarbon solvent, e.g., (cyclo)hexane or benzene, with 1,3-butadiene is brought into contact with an organolithium compound at -10-40 deg.C in the presence of 200-600ppm, based on 1,3-butadiene, 1,2-butadiene, and 0.1-10mol, per g.atom of the organolithium compound, of an ether compound, e.g., tetrahydrofuran, 1,2-dimethoxybenzene or (di)ethylene glycol dimethyl ether. When the polymer conversion is within 10%, the reaction mixture is polymerized continuously at 85-120 deg.C. In this way, polybutadiene can be produced without formation of gel-like polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing polybutadiene having excellent processability and impact resilience.

Controlling the monomolecular weight distribution and degree of branching in polybutadiene (with p+) tium compound as an initiator is important in preventing fluidity at room temperature and improving processability and physical properties.

Various methods have been known for controlling the molecular weight distribution and degree of branching of polybutadiene using organolithium compounds as initiators, among which continuous polymerization at high temperatures is the most industrially advantageous method.

Continuous polymerization at high temperatures reduces the viscosity of the polymer solution, so the stirring power is small, the overall heat transfer coefficient is large, and the temperature difference between the polymerization temperature and the refrigerant becomes large, making it easy to remove polymerization heat and achieve high concentration polymerization. This is the most preferable production method from the viewpoint of energy saving and productivity, since it is possible to recover the solvent from the polymer solution after polymerization using a solvent such as a flask song.

As a method of controlling the molecular weight distribution and degree of branching of polybutadiene at high temperatures, when performing continuous polymerization at high temperatures using a completely mixed tank reactor, such as Japanese Patent Publication No. 45-28191 and Japanese Patent Publication No. 45-28191, the polymerization system 1,2 inside
- If the amount of butadiene is low, a gel-like polymer will form and adhere, and furthermore, the vulcanizate/shade of the polybutadiene produced will be inferior in terms of tensile strength and impact resilience.

1.3-butadiene and organolithium initiator at once
The method disclosed in Japanese Patent Publication No. 47-22688, in which the reaction is started instantaneously under Takahata at -235°C and 7-polymerization is carried out, has a high polymerization initiation speed, so the amount of initiator added must be adjusted to obtain a polymer with an appropriate Mooney viscosity. There are problems in that it is difficult to control, tends to produce polymers with high Mooney viscosity, and requires a large amount of organolithium initiator to obtain polymers with relatively low Mooney viscosity.

JP-A-51-41781 describes a complicated method in which the amount of catalyst charged is periodically varied in continuous adiabatic polymerization in a flow tube.
Since the temperature at the end of the polymerization is as high as 155 to 250°C, gel-like polymers are likely to form (there are other problems. Furthermore, Japanese Patent Publication No. 47-22689 shows a method for controlling the degree of branching of polyphridienes. There is a known method in which a monomer and a catalyst are mixed in contact for a long time at -5 to 25 degrees Celsius to produce a polyfunctional lithium compound with a low degree of polymerization, and then polymerized at a polymerization temperature of 40 to 80 degrees Celsius. Processing time is long;
This method is industrially disadvantageous because the polymerization temperature is low.

The inventors of the present invention have intensively investigated a method for obtaining polybutadiene, which does not produce gel-like polymers and does not have the formation and adhesion of gel-like polymers, does not have low-temperature flow, and has poor processability and impact resilience using an industrially advantageous continuous polymerization method. and, in the presence of a trace amount of 1,2-butadiene, a mixture of a carbonaceous arsenide solvent and L3-butadiene is contacted and mixed with an organolithium compound in advance, and then polymerized continuously at high temperature. I found it.

That is, in the present invention, when producing polybutadiene by continuous polymerization using an organolithium compound as an initiator in a hydrocarbon solvent, ether, L2-dialkoxybenzene, ethylene glycol dialkyl ether)
A hydrocarbon solvent and a crystalline compound of 1,3-butadiene are added in the presence of 0.1 to 10 moles per 1 gram atom of lithium of an ether compound selected from R-F Lengellic dialkyl ethers. With organic lithium compounds, the polymerization conversion rate is 1 at low temperatures of -10 to 40℃.
After contact mixing within a range not exceeding 0%, 85-120℃
The present invention relates to a method for producing polyfridiene having excellent processability and impact resilience, which is characterized by carrying out polymerization at a reaction temperature of .

The organic lithium compounds used in the present invention include ethyllithium, propyllithium, n-butyllithium,
Alkyllithium dilithium such as ec-butyllithium, tert-butyllithium, amyllithium, alkylene dilithium, phenyllithium, 1,4-
71-norlithium such as dilithiobenzene is used.

The amount of these organolithium compounds used is 0.02 to 5 mmol, preferably 0.02 to 5 mmol per 1007 of 1,3-butadiene.
5-2 mmol.

As the hydrocarbon solvent used in the present invention, aliphatic hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons that are liquid under polymerization conditions can be used.

Examples of suitable carbon arsenic solvents include n-butane, 1-butene, 2-butene, n-pentane, 2-; If-1, 2-methylbutene-2, iso-pentane, n-
One or a mixture of two or more of hexane, +1-hebutane, n-octane, iso-octane, cyclohexane, methylcyclopentane, ethylcyclohexane, benzene, ethylbenzene, etc. is used.

The polymerization solvent is 0,5 parts by weight per 1 part by weight of 1,3-butadiene.
~10 parts by weight are used, preferably 1 to 6 parts by weight.

1,2-butadiene is 200% compared to 1,3-butadiene
~6 0 0 1) I) m used. If the content of 1,2-butadiene is less than 200 ppm, gel-like polybutadiene will be produced in the reactor during long-term continuous polymerization, which will further clog the reactor, piping, etc. Polybutadiene has a high degree of branching and low temperature IN,,j
Although there is no t, the tensile strength, impact resilience, etc. of the vulcanizate are inferior. Again 1
, If the content of 2-butadiene exceeds 6001')I)+11, the polymerization activity decreases. inferior in points. As described above, in the method of the present invention, it is necessary that the amount of 1,2-butadiene in the polymerization system is within an appropriate range, and even a minute amount may have an effect.

In the present invention, a continuous transfer agent such as toluene other than 1,2-butadiene is not preferable, and when toluene is added to the polymerization system, a large amount of low molecular weight polymer is generated, so it is preferable from the viewpoint of low-temperature flow vulcanizate rebound resilience. do not have.

The ether compound is used in such a range that the vinyl content of polybutadiene produced by about 01 to 10 moles per gram atom of lithium in the organolithium compound is less than 30%.

The ether compound activates the organolithium compound as a polymerization initiator and increases the polymerization activity.

The amount of ether compound is 1 lithium of organolithium compound
If it is less than 0.1 mole per gram atom, the polymerization initiation rate will be low and a large amount of organic lithium compound will be required, and furthermore, the low molecular weight component will increase, so the low fH flow will be greatly increased.
This is not preferable because the rebound resilience of the body object decreases. 10 again
If the vinyl content of the polybutadiene produced exceeds 30 molar
This is undesirable in terms of impact resilience of the vulcanizate, since polymers containing many low molecular weight components are produced.

The ether compound used in the present invention is a cyclic ether, 1
, 2-jethoxybenzene, ethylene glycol cyanobyl ether, and diethylene glycol dialkyl ether, specifically tetrahydrofuran, 2-methyltetrahydrofuran, 3-ethyltetrahydrofuran, dioxane, 1,2-dimethoxybenzene, 1 , 2-jethoxybenzene, 1,2-dimethoxy-4-ethylbenzene, 1,2-dimethoxy-5-ethylbenzene, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol shiftyl ether, ethylene glycol dioctyl ether , diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol'/Full 1. Full etc. are used. Dialkyl ethers, alkyl allyl ethers, and the like are not preferred because they require large amounts for polymerization activation.

The polymerization reaction is carried out by contacting and mixing a mixture of a hydrocarbon solvent and 1,3-butadiene with an organolithium compound at -10 to 40°C to an extent that the polymerization conversion does not exceed 10%, and then
The polymerization is carried out in a continuous manner at 0°C.

The ether compound is added in advance to the hydrocarbon solvent.

The 1,2-butadiene is pre-added into the 1,3-butadiene or hydrocarbon solvent.

One of the features of the method of the present invention is that the mixture of hydrocarbon solvent and 1,3-butadiene is catalytically mixed with a polymerization initiator, i%l IJ thium compound, prior to introduction into the polymerization reactor.

This contact mixing is carried out at 1 - 40°C, and the polymerization conversion rate is 1.
less than 0% of the hydrocarbon solvent by catalytic mixing, 1
The purpose of this method is to remove trace amounts of impurities such as water, acetylenes, and aldehydes contained in ,3-butadiene using an organic lithium compound activated by an ether compound, and is described in Japanese Patent Publication No. 47-22689. It is not intended to produce a polyfunctional lithium compound with a low degree of polymerization. Therefore, the contact mixing time may be short, less than 5 minutes.

If the contact mixing temperature is less than 110° C., the activation of the organolithium compound by the ether compound will be insufficient, and the removal of impurities will also be insufficient. Furthermore, if the contact mixing temperature exceeds 40°C, 1,2-butadiene, which has the effect of preventing gel formation during the subsequent high-temperature polymerization at 85 to 120°C, will be consumed in advance by the reaction, which is not preferable. If the polymerization conversion rate exceeds 10 before the polymerization is carried out at a high temperature, the low-temperature flow of the final polymer will increase, which is not preferable.

Also in the method of the present invention, if a mixture of a hydrocarbon solvent and 1,3-butadiene is introduced into the polymerization reactor all at once without contacting with the organolithium compound, trace impurities will not be removed sufficiently and the organolithium compound will not be activated. The Mooney viscosity of the coalescence increases, a large amount of organolithium compound is required to obtain a polymer with the desired Mooney viscosity, and the molecular weight distribution often becomes broader, causing problems in terms of impact resilience of the vulcanizate. Undesirable polymers are formed.

Therefore, the method of contact-mixing a mixture of a hydrocarbon solvent and 1,3-butadiene with an organolithium compound before introducing it into a polymerization reactor produces a polymer with excellent processability and impact resilience with a small amount of an organolithium compound. can get.

The polymerization temperature of the present invention is 85 to 120°C. If it is less than 85°C, there is no formation of branched polymers, so low temperature flow is large, and the molecular weight distribution is narrow and processability is poor in five points, so 120°C is not preferable. If it exceeds this, the formation of branched polymers will be significant, and often gel-like polymers will be formed, and furthermore, the molecular weight distribution will become too broad, and the impact resilience of the vulcanizate will decrease because it contains many low molecular weight components, which is not preferable. do not have.

In the polymerization temperature range of the present invention, there is no low-temperature flow of the polymer, and a polymer with poor processability and impact resilience can be obtained.

Further, even if continuous polymerization is carried out for a long period of time due to the action of 1,2-butadiene and the ether compound, the amount of gel-like polymer deposited inside the reactor is very small.

In the continuous polymerization of the present invention, a tank reactor or base reactor is usually used.
The reaction is carried out using one or two reactors, and the average residence time (reactor volume/flow; -) is usually 0.3 to 3.0 hours. Under such conditions, the polymerization reaction is substantially completed, and the polymerization conversion rate reaches 90% or more.

Polymerization is terminated by adding a polymerization terminator such as water, alcohols, phenols, or organic carboxylic acids. Also, if desired, silicon tetrachloride, tin tetrachloride, diethyl adipate,
The polymerization terminator may be added after adding a polyfunctional coupling agent such as diethyl carbonate.

According to the present invention, due to the overall effect of the requirements, the degree of branching and molecular weight distribution are appropriate, and there are few low molecular weight components, so processability is good, and gel-like polymers do not form or adhere to the polymerization equipment ( Moreover, a polymer with excellent impact resilience of the vulcanizate can be obtained.

The present invention will be further described below with reference to examples, but the present invention is not limited by these examples unless it goes beyond the gist of the invention.

Various measurements were performed using the following methods.

The microstructure is 1], λ4orero (Chim, e,
The low temperature flow (cold flow) determined by the yOJ method of Incj 41758 (1959) has a pressure of 3.51b/i.
n2, temperature 50° C., and extrusion through a 1/4 inch orifice.

After leaving it for 10 minutes to reach a steady state, reduce the extrusion speed.
The value was expressed in milligrams per minute.

Extrusion processability was determined using a 2-inch extruder (screw rotation speed 3).
Q rpln, vent temperature 80℃ 1 cylinder temperature 7
0° C.) and 1 temperature according to ASTM D-2230-63T.

The roll wrapping property was evaluated using a 10-inch roll at 60°C.

Tensile properties were measured according to JIS K6301.

Repulsion elasticity was measured at 25℃ using a Dunlop trypsometer.
Measured at 70°C.

Examples 1 to 4 Comparative Examples 1 to 8 Polybutadiene was polymerized using one tank-type reactor equipped with a 154 stirrer and a jacket. 1,3-butadiene containing 1,2-butadiene 1.8 kg/Hr, cyclohexane containing tetrahydrofuran 9.0 kg/Hr
r.

11-Butyllithium was introduced into a continuous reactor under the conditions shown in Table 1, and polymerization was carried out continuously for 72 hours with an average residence time of 1 hour.

In Example 4, 1,2-dimethoxybenzene was used instead of tetrahydrofuran, and in Comparative Example 6, a solvent of cyclohexane/Toluev (9515 weight ratio) was used instead of cyclohexane.

Note that 1,3-butadiene and cyclohexane or cyclohexane/toluene were mixed in advance in the piping from the storage tank to the anti-core type, and the mixture was further brought into contact with Kn-butyllithium at 10°C for 20 seconds, and then introduced into the reactor. . In Comparative Example 5, a mixture of 1,3-butadiene and cyclohexane and n-butyllithium were separately introduced into the reactor. The polymer contains 0.5 g of 2,6 per 1007 of polymer in the polymer solution.
After addition of -ditertiary-butyl p-cresol, the solvent was removed by steam stripping and then dried with a 110C hot roll to obtain a product.

The polymerization results and properties of the polymer are shown in Table 3.1.

Evaluation of processability was carried out on the roll wrapping property and extrusion processability of the products that were kneaded and blended with the vulcanization accelerator and sulfur excluded as shown in Table 2.2. Evaluation of vulcanizate is Fang 2
After kneading and blending according to the formulations shown in the table, the samples were vulcanized at 145°C for 40 minutes.

Claims (1)

[Claims] (1) When producing polybutadiene by continuously polymerizing in a hydrocarbon core medium using an organolithium compound as an initiator, and : D I
Hydrocarbon, in the presence of 01 to 10 mol of an ether compound selected from ether, 112-siloxane, ethylene glycol dialkyl ether, and diethylene glycol dialkyl ether per 1 gram atom of lithium of the organolithium compound; With a mixture of medium and 1,3-butadiene
With IJ thium compound, the polymerization conversion rate is 10 at -10 to 40℃.
A method for producing polybutadiene, which comprises carrying out the polymerization at a reaction temperature of 85 to 120°C after contact-mixing within a range not exceeding