JPS61231013A - Production of conjugated diene copolymer - Google Patents

Abstract

PURPOSE:To produce the titled copolymer which gives a cured article having a wide temperature dependence of the tandelta, by polymerizing a vinyl aromatic compound with a conjugated diene compound in the presence of a polyether or a tert. polyamine by using specified conditions. CONSTITUTION:To 100pts.wt. monomer mixture comprising 5-35pts.wt. vinyl aromatic compound and 95-65pts.wt. conjugated diene compound, 200-1,000pts. wt. hydrocarbon solvent, 0.01-0.2pt.wt. organolithium compound as an initiator and 0.01-3mol, per Li atom, of a polyether or a tert. polyamine, and the polymerization of the mixture is started at -10-50 deg.C. The polymerization is continued until the maximum polymerization temperature is 60-120 deg.C and the polymer conversion reaches 90-99% at an elevated temperature which can give a difference of 40 deg.C or larger between the maximum polymerization temperature and the polymerization initiating temperature. The polymerization is further continued while 1-5pts.wt. conjugated diene compound is being added to the reaction system continuously or intermittently. In this way, a conjugated diene copolymer containing a total of 1,2-bonds and 3,4-bonds of 20-70% is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to a method for producing a copolymer in which the contents of vinyl aromatic compounds and vinyl bonds are distributed in the polymer chain.

b. Conventional technology Recently, rubber materials for automobile tires have been developed to have low rolling friction resistance to improve fuel efficiency, high wet skid resistance to improve braking characteristics on wet roads, and high wet skid resistance to improve braking characteristics on wet roads. In order to improve the braking characteristics in the field, it is required to have high ice skid resistance, and to improve durability, it is required to have high breaking strength. A polymer containing polymer segments having different glass transition temperatures over a wide range is required as a rubber material that satisfies these characteristic values. Such polymers can be used in scanning calorimeters (D
SC), the width of the endothermic dislocation region of the glass transition temperature (T
Conventionally, as a method for obtaining a polymer containing segments with different glass transition temperatures, which exhibits characteristics such as a wide temperature dispersion of anδ), an organic lithium compound is used as an initiator.
A method is known in which two random styrene-butadiene copolymers having different bound styrene contents are combined in a block, and a method in which the blocks are combined and then radially combined using a polyfunctional coupling agent. Also, JP-A-56-14
Publication No. 3209 discloses that a styrene-butadiene copolymer having a specific molecular terminal structure has excellent rolling resistance characteristics and wet grip, but in this case, it is insufficient in terms of rolling friction resistance. . Also, JP-A-59-
Japanese Patent No. 142214 discloses a method for producing a styrene-butadiene copolymer that specifies a method for adding additional monomers, but in this case, the balance between wet kid resistance and ice skid resistance is insufficient. Similarly, using an organolithium compound as an initiator and varying the amount of ether added during polymerization, two polymers with different amounts of 1,2-bond gold in the polybutadiene moiety (polybutadiene-polybutadiene,
(polybutadiene-styrene-butadiene copolymer, styrene-butadiene copolymer-styrene-butadiene copolymer, etc.) are combined in a block form, and then combined in a block form and then radially combined with a polyfunctional coupling agent. method is known.

C2 Problems to be Solved by the Invention However, since the polymers obtained by these methods have two segments with different glass transition temperatures, the tan of the vulcanizate is
Broadening of δ during temperature dispersion is limited, and there are problems such as a trade-off between wet skid resistance and ice skid resistance and poor fracture strength. Also known is a method in which 1,3-butadiene is polymerized using an organolithium initiator at an elevated temperature in the presence of an ether compound, or a method in which 1,3-butadiene and styrene are copolymerized. Polymers produced by the former method contain segments with different amounts of 1 and 2 bonded gold in the polybutadiene molecular chain, but the broadening of the tan δ of the vulcanizate during temperature dispersion is limited, and the fracture strength is low. Also inferior. For polymers produced by the latter method, the tan δ of the vulcanizate becomes wider during temperature dispersion, but because polystyrene blocks are formed at the ends of the polymer, the tan δ value of the vulcanizate at 50 to 80°C is large. This is unfavorable in terms of rolling friction resistance.

The present inventors found that the temperature distribution of tan δ of the vulcanizate was wide (,
As a result of extensive research into a method for easily obtaining a conjugated diene copolymer that has a small JAN δΦ value at 50 to 80°C, the present invention has been achieved.

A means for solving the d0 problem, that is, the present invention, in order to solve the above problems, is to solve the above problems by using an organic lithium compound as an initiator, 5 to 35 parts by weight of a vinyl aromatic compound, and 95 parts by weight of a conjugated diene compound in a hydrocarbon solvent.
~65 parts by weight of a monomer mixture consisting of 1,2 parts by weight,
When producing a conjugated diene copolymer containing 20 to 70% of bonds and/or 3,4 bonds, the polymerization initiation temperature is -10 to 5 in the presence of polyether or tertiary polyamine.
0°C, the maximum polymerization temperature is 50 to 120°C, and the difference between the maximum polymerization temperature and the polymerization initiation temperature is at least 40'C or more, and the polymerization conversion is in the range of 90 to 99%. The object of the present invention is to provide a method for producing a conjugated diene copolymer, which comprises adding 1 to 5 parts by weight of a conjugated diene compound continuously or intermittently to further polymerize the polymer.

The present invention also includes a method for producing a conjugated diene copolymer, characterized in that the polymerization of the conjugated diene copolymer is terminated with a polyfunctional coupling agent.

Furthermore, after the polymerization of the conjugated diene copolymer is completed, tin halide compounds, tin compounds of organic carboxylic acids, nyltin compounds, isocyanate compounds, epoxy groups, ketone groups, aldehyde groups, ester groups, and nitrile groups are added. It also includes a method for producing a conjugated diene copolymer, characterized in that the polymerization is terminated with a compound selected from at least one dialkylamino-substituted aromatic compound.

The conjugated diene compounds used in the present invention include 1.3-butadiene, isoprene, 1.3-pentadiene, 2.3-
Examples include dimethylbutadiene, preferably 1.3
-butadiene, isoprene.

Examples of the vinyl aromatic compound include styrene, P-methylstyrene, 0-methylstyrene, P-butylstyrene, and vinylnaphthalene, with styrene being preferred.

As the hydrocarbon solvent, one or more selected from butane, pentane, 2-methylbutene, 1-methylbutene, hexane, heptane, cyclohexane, methylcyclopentane, octane, benzene, etc. can be used. The amount of hydrocarbon solvent is 2 to 10 parts by weight of the monomer mixture.
Parts by weight are used.

As an organic lithium compound, n-butyllithium, 5e
c-butyllithium, tar t~butyllithium, n
-Hexyllithium, 1,4-dilithiobutane, a reaction product of butyllithium and divinylbenzene, etc. are used.

The amount of the organic lithium compound used is 0.01 to 0.2 parts by weight per 10 parts by weight of the monomer.

Examples of polyethers and tertiary polyamines include ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether,
Diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, 2-methoxymethyltetrahydrofuran, 2.5-
dimethoxymethyltetrahydrofuran, N, N, N,'
N'-tetramethylethylenediamine1. ■, 2
- Dibiperidinoethane and the like.

diethyl ether, tetrahydrofuran, dioxane,
Ethers such as pyridine, triethylamine and tertiary
When grade amines are used, the dependence of the polymerization temperature on the microstructure of the conjugated diene copolymer portion is small;
Undesirable.

The amount of polyether or tertiary polyamine used is 0.01 to 3 per 1 atom equivalent of lithium in the organolithium compound.
The amount is adjusted by mole, preferably in the range of 0.05 to 1 mole, so that the sum of the average 1,2 bond and 3.4 bond amount of the conjugated diene copolymer is in the range of 20 to 70%. .

The polymerization reaction is carried out using polyether or tertiary polyether in a hydrocarbon solvent.
A monomer mixture of 5 to 35 parts by weight of a vinyl aromatic compound and 95 to 65 parts by weight of a conjugated diene compound is polymerized using an organolithium compound as an initiator in the presence of a class polyamine at a polymerization initiation temperature of 110 to 50°C. The polymerization is carried out at an elevated temperature such that the maximum polymerization temperature is in the range of 60 to 120°C, and the difference between the maximum polymerization temperature and the polymerization initiation temperature is at least 40°C or more. The difference between the maximum polymerization temperature and the polymerization initiation temperature is at least 40°C; below 40°C, the peak width of the temperature dispersion of tan δ of the vulcanizate of the conjugated diene copolymer produced is narrow, and wet skid resistance and ice It is difficult to achieve both skid resistance.

The polymerization initiation temperature is -10 to 50°C. Below -10°C, the polymerization initiation rate is slow, and above 50°C, it is difficult to make the peak width of the temperature dispersion of tan δ of the vulcanizate broad.

The maximum polymerization temperature is 60 to 120°C. If it is less than 60°C, it is difficult to make the peak width of the temperature dispersion of tan δ of the vulcanizate broad, and if it exceeds 120°C, the copolymerization of low molecular weight components will occur. is generated, which is unfavorable in terms of rolling friction resistance.

The polymerization reaction can be followed by a reaction with a polyfunctional coupling agent. As the polyfunctional coupling agent, those described in Japanese Patent Publication No. 49-36957 can be used. This improves rolling friction resistance and breaking strength.

Preferred polyfunctional coupling agents added after completion of polymerization include tin tetrachloride, tin tetrachloride, and tin halide compounds.
Examples of tin compounds of organic carboxylic acids include dibutyldichlortin and triphenyltin chloride, and examples of tin compounds of organic carboxylic acids include dibutyldilauryltin, butyltristearyltin, and dimethyldistearyltin. Examples of vinyl tin compounds include monovinyltributyltin and divinyldibutyltin, and examples of isocyanate compounds include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and crude diphenylmethane diisocyanate. Furthermore, the dialkylamino-substituted aromatic compound containing at least one epoxy group, ketone group, alnahydride group, ester group, or nitrile group is a compound represented by the following general formula.

At the stage when the polymerization conversion rate reaches a range of 90 to 99%, preferably 95 to 99%, 1 to 5 parts by weight of a conjugated diene compound is added continuously or intermittently into the polymerization system to further polymerize. It is done. Even if a conjugated diene compound is added at a stage where the polymerization conversion rate is less than 90% or more than 99%, randomization polymerization between the conjugated diene compound and the vinyl aromatic compound is incomplete, and the polyvinyl aromatic compound is formed at the end of the polymer. The vulcanizate is unfavorable in terms of rolling friction resistance.

When the polymerization conversion rate reaches 90 to 99%, a predetermined amount of a conjugated diene compound is added, a vinyl aromatic compound is randomly polymerized, and then the mixture can be treated with a polyfunctional coupling agent.

If the amount of the conjugated diene added is less than 1 part by weight, the randomization polymerization of the conjugated diene and the vinyl aromatic compound will be incomplete and the rolling friction resistance will increase.

If the amount exceeds 5 parts by weight, the number of lithium active terminals that are deactivated due to impurities contained in the added conjugated diene increases, and the coupling efficiency decreases especially when coupling with a tin compound etc. after the completion of polymerization, resulting in a decrease in rolling friction resistance. Characteristics are not improved, which is not desirable.

The reaction (treatment) with the polyfunctional coupling agent is not particularly limited, but is carried out at a temperature below the temperature reached for polymerization. The reaction time varies depending on the type of polyfunctional coupling, but is within 3 hours, usually within 1 hour.

Further, the copolymer of the present invention may be used alone or at 80% by weight.
Examples of other diene rubbers below include 1f natural rubber, IR, BR
, Blend with other SBR etc. to make ordinary rubber compounding agent,
For example, 10 to 120 parts by weight of a filler such as carbon black and 0.5 to 5 parts by weight of a sulfurizing agent are blended with 100 parts by weight of the rubber content, and the composition can be suitably used for tires and various industrial products.

e. Examples Hereinafter, the present invention will be explained in detail in Examples, but the invention is not limited to the scope of Examples unless it exceeds the gist thereof.

In this example, the microstructure was determined using an infrared method (Morello method).
I asked for it. The styrene content was measured using a calibration curve previously determined using absorption based on the absorption of 699aa-' phenyl group.

The tensile strength according to JIS K6301 was used as an index for breaking strength.

The rolling friction resistance characteristics are JAN δ measured at 50°C.
The Φ value was used. tan δ was measured using a viscoelastic spectrometer (manufactured by Iwamoto Seisakusho) (frequency: 15 Hz).

Wet skid resistance and ice skid resistance were measured using a Skin Tochister manufactured by Stanley.

Wet skid resistance was measured at room temperature, and ice skid resistance was measured at -10°C.

Examples-1 to 1), Comparative Examples-1 to 6 [Preparation of Polymer A] 25% of cyclohexane was added to a 51 reactor purged with nitrogen.
00 g, butadiene 385 g, styrene 1
00g, ethylene glycol dibutyl ether t-0,
25g of n-butyllithium was charged, the temperature was raised to 20°C, 0.30g of n-butyllithium was charged, and polymerization was carried out under heat insulation. When the polymerization conversion rate of the initially charged monomers reached 96% (the temperature of the polymerization system reached 80° C.), 15 g of butadiene was continuously added for 5 minutes. 15 minutes after the addition, when the reaction conversion rate reached almost 100%, 2.
0.5 parts by weight of 6-di-t-butylcatechol was added to 100 parts by weight of the polymer, and the solution was removed and dried in a conventional manner.

Vinyl bonds in the butadiene moieties of the obtained copolymer Also, as a result of analyzing the obtained copolymer by ozonolysis-gel permeation chromatography, it was found that it contained a long chain block of styrene in which five or more styrenes were bonded consecutively. The rate is 5%
Figure 1 shows the results of measuring the differential styrene content and differential vinyl content percentage of the copolymer with respect to the polymerization conversion rate during the 0 polymerization reaction, which was as follows. Differential styrene content percentage,
The differential vinyl content percentage was determined by sampling the polymer at every 3 to 5% polymerization conversion rate and using an infrared method.

[Preparation of polymer B]

Polymerization was carried out using the same recipe as Polymer A. After the polymerization conversion rate reached almost 100%, 0.2 mol of tin tetrachloride was added to 1 mol of n-butyllithium. [Preparation of Polymer C] Polymerization was carried out using the same recipe as Polymer A.

After the reaction conversion rate reached approximately 100%, 1 mol of tolylene diisocyanate was added per 1 mol of n-butyllithium at 100°C. ML of the obtained polymer,
◆4 was 55.

The amount of vinyl bond, the amount of bonded styrene, and the amount of block bonded styrene in the butadiene moiety were the same as those of Polymer A.

[Preparation of Polymer D]

Nitrogen-substituted 5I! Into the reactor, add 2 cyclohexane
500 g - 400 g of butadiene, 100 g of styrene
g, 0.25 g of ethylene glycol dibutyl ether
Prepare, adjust the temperature to 20°C, and add 0.0% n-butyllithium.
30 g was charged and polymerization was carried out under heat insulation. The polymerization temperature reached 85°C. After the reaction conversion reached approximately 100%, the same post-polymerization treatment as for Polymer A was carried out without adding butadiene. The amount of block-bonded styrene in the obtained polymer was 25%.

[Preparation of Polymer E]

In the polymerization recipe of Polymer D, 12.5% of tetrahydrofuran was added instead of ethylene glycol dibutyl ether.
Polymerization was carried out using g.

The same treatment as for Polymer A was carried out.

The amount of vinyl bond in the butadiene part of the obtained polymer was 4
It was 8%.

The amount of block-bonded styrene was 5% or less.

[Preparation of polymer FP]

Polymerization was carried out under heat insulation according to the recipe shown in Table-2. The amount of solvent, total monomer amount, and n-butyllithium amount are Polymer A
It was made the same as. When a predetermined reaction conversion rate was reached, butadiene was added in a predetermined amount over a period of 5 to 10 minutes. The reaction conversion rate reached almost 100% 15 minutes after the addition. For the polymers F, G, , J to P that undergo the coupling reaction, 0.2 mol of tin tetrachloride was added per 1 mol of n-butyllithium. Thereafter, a predetermined amount of an antiaging agent (2,6 di-t-butylcatechol) was added, followed by desolvation and drying. The Mooney viscosity of the obtained polymer, the vinyl bond in the butadiene moiety, the amount of bonded styrene, and the amount of block bonded styrene are shown in the table.
Shown in 3.

[Made of polymer Q steel]

Polymerization was carried out using the polymerization recipe of Polymer A using 0.15 g of N,N,N',N'-tetramethylethylenediamine instead of ethylene glycol dibutyl ether. The properties of the polymer are shown in Table 3.

□ 250 cc of the above polymer according to the distribution recipe shown in Table-1
The mixture was kneaded using a plastomill and vulcanized at 145° C. for 30 minutes, and the initial evaluation results are shown in Tables 4-4.

Example 12 Example 1 was prepared using a copolymer component consisting of 860% by weight of polymer and 40% by weight of natural rubber according to the formulation shown in Table 1.
At the same time, it was kneaded and vulcanized, and the results of evaluation of its physical properties are shown in Table 4.

Examples-1 to 12 have higher tensile strength than Comparative Examples-1 to 6,
Wet skid resistance characteristics, ice skid resistance characteristics,
Excellent balance of rolling friction resistance characteristics.

Comparative examples using polymers without butadiene have large rolling friction resistance and poor fuel efficiency.
is inferior to Ice Kid in terms of rolling friction resistance properties.

Comparative Examples-3 and 4, in which the polymerization addition rate during continuous addition of butadiene was outside the range of the present invention, contained a large amount of long-chain block polystyrene, and Comparative Example-5, in which the amount of additional butadiene was large, had a low coupling efficiency. Low (rolling friction resistance is large and fuel consumption characteristics are poor. Comparative Example 6 has a small temperature rise width and a small distribution of vinyl bonds, so the balance between wet skid and ice skid characteristics is poor.

Table 1 Effect of 1,5-phenylquanicine 19 The conjugated diene copolymer prepared by the method of the present invention is produced using an organolithium initiator until the polymerization conversion rate exceeds 90%. Because the copolymerization of the vinyl aromatic compound and the conjugated diene compound takes place in the presence of the polyamine and at elevated temperatures, the end segments of the polymer are random and have a relatively high amount of 1,2 and/or 3,4 bond. As the polymerization temperature increases, the effect of the polyether or tertiary polyamine (random effect, 1, 2 and/or 3, 4
As a result, the copolymer segment (B) gradually has a lower vinyl aromatic compound content and a lower 1,2 and/or 3.4 bond amount. Next, after the polymerization conversion rate reaches 90%, since the content of vinyl aromatic compounds in the monomer is high, a conjugated diene compound is continuously or intermittently added to the polymerization system from the outside. A copolymer segment (C) with a random high vinyl aromatic compound content is obtained.

In this way, the conjugated diene copolymer of the present invention is (A)-(
It is a B)-(C) type block copolymer, and the glass transition temperature of each segment is (B) < (A) < (C).
increasing in the order of Furthermore, (A) −(B), (B) −
Between the (C) segments, there are glass transition temperatures intermediate between (A) and (B) and between (B) and (C), respectively.

g0 Effect of the invention The conjugated diene copolymer obtained by the method of the invention is:
Because the molecular chain simultaneously contains polymer segments with low to high glass transition temperatures, the temperature dispersion peak of tan δ of the vulcanizate is wide and has excellent wet skid properties, ice skid properties, and fracture strength. Poly(
Since it does not contain block polymers (vinyl aromatic compounds), it has excellent rolling friction resistance.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between the differential styrene content percentage and the differential vinyl content percentage of the copolymer with respect to the polymerization conversion rate during the polymerization reaction.

Claims (2)

[Claims] (1) In a hydrocarbon solvent, using an organolithium compound as an initiator, a monomer mixture consisting of 5 to 35 parts by weight of a vinyl aromatic compound and 95 to 65 parts by weight of a conjugated diene compound is polymerized to form a 1,2 bond. When producing a conjugated diene copolymer containing 20 to 70% of 3,4 bonds in total, in the presence of polyether or tertiary polyamine, the polymerization initiation temperature is -10 to 50 °C, and the maximum polymerization temperature is is 60-120℃,
The difference between the maximum polymerization temperature and the polymerization initiation temperature is at least 40℃
The polymerization conversion rate is 90 to 99 when polymerized at an elevated temperature of 90 to 99.
% range, 1 to 5 parts by weight of a conjugated diene compound is added continuously or intermittently to 100 parts by weight of the monomer mixture, and further polymerization is carried out. A method for producing a diene copolymer. (2) The method for producing a conjugated diene copolymer according to claim (1), which comprises terminating the polymerization with a polyfunctional coupling agent after completion of the polymerization.