JPS59142214A - Production of branched polymer - Google Patents

Abstract

PURPOSE:To obtain a branched polymer excellent in processability, etc., in good efficiency, by polymerizing a conjugated diene with a vinyl-substituted aromatic compound in the presence of an organolithium catalyst and adding a polyfunctional treating agent in a specific stage of the polymerization reaction. CONSTITUTION:A conjugated diene (e.g., 1,3-butadiene) is adiabatically copolymerized with a vinyl-substituted aromatic compound (e.g., styrene) in the presence of a polar compound (e.g., diethylene glycol dimethyl ether) in a hydrocarbon solvent (e.g., n-hexane) by using an organolithium catalyst comprising a hydrocarbon to which at least one lithium atom is bonded (e.g., n-butyllithium). A polyfunctional treating agent (e.g., silicon tetrachloride or tin tetrachloride) is added to the polymerization system within the period during which the molar ratio of the remaining conjugated diene to the remaining vinyl-substituted aromatic compound is 0.1 or greater to obtain the purpose branched polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a branched polymer, and relates to an improvement in the method for obtaining a branched polymer using an organolithium initiator.

Conventionally, conjugated diene polymers, especially rubbers solution-polymerized using organolithium initiators, have excellent physical properties but are inferior in processability and cold throw, and many attempts have been made to improve them. There is. Among these methods, many proposals have been made to obtain a branched polymer using a coupling agent as an effective means for improving processability and cold flow.

For example, Japanese Patent Publication No. 49-36957, Japanese Patent Publication No. 44-49
No. 96 and Special Publication No. 52-5071.

′! i-When randomly copolymerizing a conjugated diene and a vinyl aromatic compound using an organolithium initiator,
A method of polymerization in the presence of polar compounds such as ethers, thioethers, and tertiary amines is known. Therefore, if you try to obtain a branched product with a random copolymer of butadiene and styrene, it will polymerize in the presence of a polar compound,
It is thought that it can be produced by adding a coupling agent after the polymerization is completed, but if this is attempted to be carried out industrially, many problems will arise. In other words, when attempting to polymerize adiabatically to obtain a polymer, the temperature within the system rises due to the heat of polymerization.In order to lower the temperature of the system, it is better to lower the monomer concentration, but if the monomer concentration is lowered, Productivity decreases.

Furthermore, when the temperature of the system is raised, complex reactions occur in the presence of polar compounds, and the coupling reaction stops proceeding for some reason.

This is also shown, for example, in Experiment B on page 5 of Japanese Patent Publication No. 52-5071.

Under such circumstances, the present inventors have conducted intensive studies on a method that allows polymerization at a relatively high temperature with good productivity and that also allows the coupling reaction to be carried out efficiently, and have arrived at the present invention.

The present invention provides a method for adiabatically polymerizing a conjugated diene and a vinyl-substituted aromatic compound in the presence of a polar compound using an organolithium initiator in a hydrocarbon solvent.
This is a method for producing a randomly branched polymer of a conjugated diene and a vinyl-substituted aromatic compound, which is characterized in that the polymer is added when the molar ratio of the remaining conjugated diene to the vinyl-substituted aromatic compound is 0.1 or more.

According to the present invention, an excellent method for producing branched polymers has been discovered, which has high coupling efficiency using a multifunctional processing agent and can be carried out at relatively high temperatures, and is of extremely great industrial value. The polymer obtained by the present invention is a polymer that is well balanced in terms of physical properties, processability, cold flow, etc. Moreover, the molecular weight distribution shows a distribution consisting of two peaks: a peak consisting of a linear polymer on the low molecular weight side and a peak consisting of a branched polymer on the high molecular weight side. The positions, proportions, etc. of both of these peaks can be freely controlled by the method of the present invention.

The organolithium catalyst used in the present invention includes:
It is a hydrocarbon that has at least one lithium atom bonded to it. For example, ethyllithium.

Propyl lithium, n-butyl lithium! 1-butyllithium, t-zotyllithium, phenyllithium, 1
．． 4-dilithiobutane, 1,5-dilithiopentane, 1
．． 2-dilithio-1,2-phenylethane e 1 e
3+s) lylithiocyclohexane, and particularly preferred are n-zotyllithium and S-zotyllithium. These organolithium initiators may be used not only alone but also as a mixture of two or more. The amount of the organolithium initiator to be used is determined depending on the desired molecular weight of the produced polymer, etc., but it is usually 0.1 per 1001 monomers.
~5 mmot, preferably 0.3-2 rnrn
It is used about ot.

The monomers used to make the polymers of this invention are conjugated dienes and vinyl substituted aromatic compounds. Conjugated dienes include, for example, 1,3-citadiene, 2-methyl-1,3-butadiene (isoprene)+2+"-dimethyl-1,3-butadiene, l,3-pentadiene, and especially 1°3-" Butadiene and isoprene are preferred. On the other hand, examples of vinyl-substituted aromatic compounds include styrene, 0-methylstyrene, and p-methylstyrene.

Examples include α-methylstyrene*-p-tert-butylstyrene, vinylnaphthalene, and styrene is particularly preferred. There is no particular restriction on the proportions of the conjugated diene and the vinyl-substituted aromatic compound, but in order to obtain a rubbery polymer, it is preferable that the conjugated diene be on a 50-weight plate containing all the monomers. At this time, the conjugated diene compound and the vinyl-substituted aromatic compound may be used singly or as a mixture of two or more thereof.

The hydrocarbon solvent used in the present invention is not particularly limited, but for example, n-pentane.

1so-pentane, n-hexane, n-hebutane.

igo-octane, decane, cyclohexane, ethylcyclohexane, benzene, toluene fl:, tolfi;
Particularly preferred solvents are hexane and cyclohexane. These hydrocarbon solvents may be used alone or in combination of two or more.

The polar compound used in the present invention may be one that randomly copolymerizes a conjugated diene and a vinyl-substituted aromatic compound, and conventionally known compounds can be used. These polar compounds include many compounds such as ethers thioethers, tertiary amines, specific metal phosphides, alkali metal alkoxides, and alkali metal sulfonates. Examples of these compounds include diethyl ether, di-propyl ether, di-n-butyl ether, ethyl butyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol shiftyl ether, diethylene glycol dimethyl ether, and -) ethylene glycol diethyl. ether.

Tetrahydrofuran, α-methoxytetrahydrofuran, dioxane, trimethylamine, triethylamine,
Tetramethylethylenediamine, tetramethylpropanediamine, N-methylmorpholine, hexamethylphosphoramide, dimethylsulfide, diethylsulfide,
Examples include potassium t-butoxide, potassium amylmoxide, sodium alumyl oxide, sodium dodecylbenzenesulfonate, potassium hexadecylbenzenesulfonate, and the like. Preferred among these compounds are tetrahydrofuran, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, tetramethylethylene diamine, potassium t-butoxide, and the like.

These compounds may be used not only as a single type but as a mixture of two or more types.

The polyfunctional treatment agent used in the present invention is a treatment agent having at least two reactive sites, and types of the polyfunctional treatment agent used include polyhalide, poly, epoxide,
Includes polyisocyanates, polyimys, polyaldehydes, polyvinyl compounds, polyketones, polyanhalides, polyesters, etc. These compounds may be used as a mixture of compounds having two or more types of functionality, or may be a single compound having different reactive sites.

Examples of these compounds include silicon tetrachloride.

Methyl silicon trichloride, butyl silicon trichloride, tin tetrachloride, methyl tin trichloride, butyl tin trichloride.

Carbon tetrachloride, epoxidized soybean oil, epoxidized linseed oil,
Benzene-1,2,4-)lisocyanate, naphthalene-1,2,5,7-titriisocyanate, tri(1
-aziridinyl)phosphine oxide, 2,4.6-
tri(aziridinyl)' + 3+ 5)'J azine, divinylbenzene, etc.

Particularly preferred treating agents in the present invention are silicon compounds or tin compounds such as silicon tetrachloride and tin tetrachloride, and these may be used alone or in combination of two or more. These treating agents generally vary depending on the copolymer to be used, which can range from 0.1 to 10 equivalents of the amount of active catalyst used, but are usually 0.
．． 3 to 08 equivalents.

In the present invention, the processing agent has a polymerization rate of conjugated diene of 8.
Add from 0 to 99%, preferably from 85 to 98 qb.

In the present invention, the polyfunctional processing agent must be added at a molar ratio of the remaining conjugated diene to the vinyl-substituted aromatic compound of 0.1 or more, preferably 1 or more.

When the amount is less than this, the efficiency of the coupling reaction is poor,
Mooney viscosity does not increase.

In the present invention, the polymerization reaction is usually carried out adiabatically in an atmosphere of an inert gas such as nitrogen, but some cooling may be performed through the jacket of the polymerization vessel or the like. That is, it means that polymerization occurs in a state where the heat of polymerization per unit time exceeds the amount of heat removed.

The pressure during polymerization also changes, but there is no particular restriction as long as the pressure is sufficient to maintain the reaction system in a liquid phase.

The polymerization temperature usually starts at 20-50°C and reaches a maximum of 80-15°C.
The temperature rises to 0℃. The maximum temperature is preferably 85-135
It is ℃. Also, the temperature when adding the multifunctional processing agent is 80°C.
~130°C is preferred. When the maximum polymerization temperature is low, the polymerization reaction is slow and it is difficult to increase the reaction rate. Furthermore, if the maximum temperature is too high, the Cassilling reaction will be difficult to proceed and will not be effective. The reaction time is 5 minutes to 3 hours after the start of polymerization, but is usually about 10 minutes to 1 hour.

The polymer obtained by the method of the present invention is isolated as a rubber by a method used in conventional solution polymerization methods. That is,
Add stabilizers etc. in the solution state to separate the formed polymer, internal properties,
The desired copolymer can be obtained by drying.

Examples are shown below, but these are intended to specifically explain the present invention and are not intended to limit the scope of the present invention.

Examples 1 to 4 and Comparative Examples 1 to 2 Butadiene 860p and styrene 285S', which had been purified and dried in advance, were placed in a polymerization vessel having an internal volume of 1 Ot and equipped with a stirrer and a jacket, which had been previously washed, dried, and purged with nitrogen.

Hexane 3540ii' and tetrahydrofuran 12
Prepare fI- and heat until the temperature of the liquid reaches 40℃,
Immediately, 0.8 g of n-butyllithium was supplied to start the polymerization reaction. Polymerization was carried out adiabatically while stirring in the polymerization reactor, and 0.25 P of silicon tetrachloride was added at the times shown in Table 1. . After the polymerization is completed, 2.6-di-t- is added to the polymer solution.
20P of butyl-p-cresol (BHT) was added and the rubber was separated by steam stripping. Table 1 shows the conditions during polymerization and the analytical values of the obtained polymer.

As is clear from this, when the polyfunctional processing agent was added within the scope of the present invention, the molecular weight force X increased and rubbers with no cold flow were obtained. When the C molar ratio was 0.01 and 0.05, the coupling reaction did not substantially occur, the Mooney viscosity before and after the reaction hardly changed, and the cold flow was significant.

Examples 5 to 9 Examples 5 to 9 Examples 5 to 9 were carried out in the same manner as in Example 1 using various polar compounds and polyfunctional processing agents. The maximum temperature during polymerization was determined by controlling the monomer concentration and polymerization initiation temperature. As is clear from Table 2, it can be seen that the addition of the multifunctional processing agent according to the method of the present invention results in good cassilling efficiency.

Margin below

Claims (1)

[Claims] 1. When a conjugated diene and a vinyl-substituted aromatic compound are adiabatically polymerized in the presence of a polar compound using an organolithium catalyst in a hydrocarbon solvent, a polyfunctional processing agent remains. The molar ratio of the conjugated diene to the vinyl-substituted aromatic compound is 0.
Method 2 for producing a randomly branched polymer of a conjugated diene and a vinyl-substituted aromatic compound, characterized in that the multifunctional treatment agent is a silicon compound or a tin compound. Method 3 for producing the polymer according to Range 1, the temperature when adding the multifunctional treatment agent is 80 to 130
A method for producing the polymer according to claim 1 or 2, wherein the temperature is