JPH05255408A - Production of carboxyl group-containing conjugated dienic polymer - Google Patents

Abstract

PURPOSE:To provide a method for efficiently producing the carboxyl group- containing conjugated dienic polymer under a high temperature which is advantageous when the production of the carboxyl group-containing conjugated dienic copolymer is industrially performed. CONSTITUTION:The method for producing the carboxyl group-containing conjugated dienic polymer comprise polymerizing a conjugated dienic monomer in the presence of an organic lithium compound in a specific solvent (an aliphatic or alicyclic hydrocarbon) and subsequently reacting the produced living polymer with carbon dioxide in the presence of a specific Lewis base (a tertiary amine, a tertiary diamine or a linear or cyclic ether having two or more oxygen atoms in the molecule).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a conjugated polymer containing at least one conjugated diene monomer and optionally at least one copolymerizable monomer, which has a carboxyl group at the molecular end. The present invention relates to a method for producing a diene polymer.

[0002]

As a method for producing a conjugated diene rubber containing a carboxyl group, a conjugated diene monomer is polymerized in a hydrocarbon solvent using an alkyllithium catalyst as an initiator,
A method of reacting an active living end with carbon dioxide to introduce a carboxyl group at the end of the polymer (Journal of Poly
m. Science PART A vol 2, p4545-4550, 1964) and a method of introducing a carboxyl group into the polymer main chain, a method of adding thioglycolic acid to a polybutadiene having a 1,2-double bond (special Kaisho 53-65387
(Japanese Patent Publication) is publicly known.

However, in these methods, in the former method, a dimer, a trimer or the like is produced by a side reaction in the reaction between an active living terminal and carbon dioxide, and a polymer having a carboxyl group at a desired terminal is efficiently produced. I can't get it.

On the other hand, in the latter case, when a thioglycolic acid is added, a radical initiator such as AIBN is used as a catalyst. Therefore, unfavorable side reactions such as gelation of polybutadiene occur, and the carboxyl group in the polymer main chain is also efficiently produced. Cannot be introduced.

Various proposals have been made to solve these problems. For example, Japanese Unexamined Patent Publication (Kokai) No. 48-67384 discloses that the reaction rate is increased by cooling the polymer solution to -10 ° C or lower to react the active lithium terminal of the polymer with carbon dioxide. In addition, Japanese Patent Publication Sho 5
In JP-A-8-12882 and JP-B-58-33241, by using a specific reaction device and reacting an active lithium terminal of a polymer with carbon dioxide at a temperature of room temperature or lower,
Methods for suppressing side reactions have been proposed. In addition, by polymerizing isoprene, in the presence of a large amount of tetrahydrofuran (THF), that is, 75/25 (vol.
%) In a solvent (Makromol.
Chem. 183, p2071-2076, 1982) are also known.

However, the use of a large amount of THF has a problem that it becomes difficult to separate the THF from the polymerization solution and to purify the product in the solvent recovery step. As described above, a method for suppressing an unwanted side reaction and quantitatively obtaining a desired carboxyl group-containing polymer at high temperature, which is advantageous in industrial practice, has not yet been found.

[0007]

Therefore, an object of the present invention is to provide a method for producing a conjugated diene polymer containing a carboxyl group at a high temperature without causing side reaction and at a high conversion rate. is there. That is, an object of the present invention is to use a specific amount of a specific Lewis base in a non-aromatic non-polar solvent, that is, an aliphatic and / or alicyclic hydrocarbon,
An object of the present invention is to provide a manufacturing method that can be industrially implemented.

[0008]

SUMMARY OF THE INVENTION The present invention comprises at least one
Optionally at least one conjugated diene monomer
With a type of copolymerizable monomer, in a hydrocarbon solvent, using an organolithium compound as an initiator, the resulting living polymer in the presence of a Lewis base, after reacting with carbon dioxide, In the method for producing a carboxyl group-containing polymer by adding a proton donor, (A) the hydrocarbon solvent is at least one solvent selected from aliphatic hydrocarbons and alicyclic hydrocarbons, B) The Lewis base is at least one compound selected from a tertiary monoamine, a tertiary diamine, a chain ether or a cyclic ether having two or more oxygen atoms in one molecule, and the Lewis base is the above-mentioned compound. 30 to 5,0 in a hydrocarbon solvent
And (C) the reaction temperature of the living polymer with carbon dioxide is in the range of 50 to 140 ° C. The present invention relates to a method for producing a carboxyl group-containing conjugated diene polymer.

According to the method of the present invention, in industrial practice, side reactions can be suppressed under advantageous temperature conditions and a conjugated diene polymer having a carboxyl group in the polymer molecule can be efficiently produced. it can.

The present invention will be described in detail below. The carboxyl group-containing conjugated diene-based polymer in the present invention is a non-aromatic non-polar solvent containing at least one kind of conjugated diene-based monomer, and optionally at least one kind of copolymerizable monomer, That is, in an aliphatic and / or alicyclic hydrocarbon, polymerization is carried out using an organic lithium compound as an initiator, and the living polymer is mixed with carbon dioxide and carbon dioxide in the presence of 30 to 5,000 ppm of a specific Lewis base with respect to the solvent. ℃ ~
It can be produced by reacting at a temperature of 140 ° C.

The organolithium compound used in the present invention may be a monoorganolithium compound or a polyfunctional organolithium compound, or a mixture of a monoorganolithium compound and a polyfunctional organolithium compound.
Examples of the organic monolithium compound include n-propyllithium, iso-propyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, penzyllithium, and the like, but preferably n-butyllithium and sec- Butyl lithium or the like is used.

As the polyfunctional organolithium compound, for example, dilithiomethane, 1,4-dilithiobutane, 1,6
-Dilithiohexane, 1,4-dilithiocyclohexene, 1,4-dilithio-2-ethylcyclohexane,
1,3-dilithio-4-phenylbutane, 1,2-dilithio-1,2-diphenylethane, 1,10-dilithiodecane, 1,20-dilithioeicosane, 1,1-dilithiodiphenylene, 1, 4-dilithiobenzene, 1,5
-Dilithionaphthalene, dilithiopolybutadiene, dilithioisoprene, dilithiodiisoprene, dilithiopolyisoprene, 2,2'-2 "-trilithio-p-terphenyl, 1,3,5-trilithiobenzene, 1, 3,5
-Trilithio-2,4,6-triethylbenzene and the like. In addition to the above, an organolithium compound containing substantially a polyfunctional organolithium compound by reacting a monoorganolithium compound with another compound may be used.

Among these examples, particularly representative catalysts are
It is a reaction product containing at least two of a monoorganolithium compound and a polyvinyl aromatic compound. For example, a reaction product of a monoorganolithium compound and a polyvinylaromatic compound (JP-A-48-103690), a monoorganolithium compound and a conjugated diene or a monovinylaromatic compound are reacted, and then a polyvinylaromatic compound is added. Reaction products obtained by reacting or reaction products obtained by simultaneously reacting a monoorganolithium compound, a conjugated diene or a monovinylaromatic compound, and a polyvinylaromatic compound (West German Patent No. 2,003,384), etc. Used.

Further, as disclosed in Japanese Patent Publication No. 50-37078, a reaction product of a monoorganolithium compound and a monovinylaromatic compound is reacted with a polyvinylaromatic compound, and then a monovinylaromatic compound is further added. The catalyst obtained by the reaction is also effective. Further, the aliphatic hydrocarbon used in the present invention is pentane, hexane, heptane, etc .; and the alicyclic hydrocarbon is cyclopentane, cyclohexane, methylcyclohexane, etc .; Any combination of the above may be used as a mixed solvent. Particularly preferred solvents include hexane and cyclohexane.

The conjugated diene monomer used in the present invention is
1,3-butadiene, isoprene, 2,3-dimethyl-
1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1,3-heptadiene,
Examples of the conjugated diene such as 1,3-hexadiene and the monomer copolymerizable with these conjugated dienes include styrene, α-methyl stymene, p-methyl styrene, divinyl benzene, methyl acrylate, methyl methacrylate and acrylonitrile. Yes, one kind or two or more kinds are used. As the preferred conjugated diene-based monomer, 1,
3-butadiene and isoprene. Further, styrene is mentioned as a preferable example of the monomer copolymerizable with the conjugated diene.

When the polymer having an active lithium terminal of the present invention is a copolymer composed of the above conjugated diene and a monomer copolymerizable therewith, the content of the copolymerizable monomer,
Alternatively, the chain distribution of the copolymerizable monomer in the copolymer chain is not particularly limited. The composition distribution of the conjugated diene and the copolymerizable monomer in the copolymer chain may be uniform in the molecular chain, or may be non-uniformly distributed in the molecular chain. It may exist as a block.

The specific Lewis base used in the present invention is
A tertiary monoamine, a tertiary diamine, and a chain or cyclic ether having two or more oxygen atoms in one molecule. Examples of tertiary monoamines include trimethylamine, triethylamine, methyldiethylamine, 1,1-dimethoxytrimethylamine, 1,1-diethoxytrimethylamine,
And compounds such as N, N-dimethylformamide diisopropyl acetal, N, N-dimethylformamide, dicyclohexyl acetal, and the like;

Examples of tertiary diamines include N, N, N ',
N'-tetramethyldiaminomethane, N, N, N ',
N'-tetramethylethylenediamine, N, N, N ',
N'-tetramethylpropanediamine, N, N, N ',
N'-tetramethyldiaminobutane, N, N, N ',
N'-tetramethyldiaminopentane, N, N, N ',
Examples thereof include compounds such as N'-tetramethylhexanediamine, diperidinopentane, and diperidinoethane;

Examples of chain ethers include ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether and tetraethylene dimethyl ether; examples of cyclic ethers include bis (2-oxolanyl) ethane and 2,2-bis ( 2-oxolanyl) propane, 1,
1-bis (2-oxolanyl) ethane, 2,2-bis (2-oxolanyl) butane, 2,2-bis (5-methyl-2-oxolanyl) propane, 2,2-bis (3,2)
Examples include compounds such as 4,5-trimethyl-2-oxolanyl) propane.

Among the Lewis bases, tertiary diamine compounds are preferable from the viewpoints of cost and effect, and among them, N, N, N ′, N′-tetramethylethylenediamine is particularly preferable. In using the compound, one kind or two kinds are used.
You may combine arbitrarily more than one kind.

The amount of the compound used is in the range of 30 to 5,000 ppm with respect to the hydrocarbon solvent used when producing the living polymer having an active lithium terminal,
Preferably from 80 to 4,000 ppm, most preferably 1
The range is from 00 to 3,000 ppm. If it is less than 30 ppm, the side reaction suppressing effect is not sufficient,
When it exceeds pm, problems of colorability and odor of the product occur.

There are no particular restrictions on the timing and method of adding the Lewis base, but when the living polymer is produced, it may be added to the solvent in advance before the addition of the organolithium catalyst, or divided during the polymerization. There is a method of adding, after the polymerizable monomer is consumed and the polymerization is completed, before the reaction with carbon dioxide, there is a method of adding, after the polymerization is completed, from the aspect of controlling the microstructure of the conjugated diene polymer. The method of adding is preferable.

In the reaction of the living polymer with carbon dioxide in the present invention, the reaction temperature is in the range of 50 ° C to 140 ° C, preferably 70 ° C to 110 ° C.
When the reaction temperature exceeds 140 ° C., the reaction rate is lowered and the amount of carboxyl groups introduced is significantly reduced. Below 60 ° C., the proportion of side reaction products does not change at all, a special device for cooling the reaction tank is required, and the viscosity increases, which is disadvantageous in industrial practice.

The carbon dioxide to be used may be solid or gaseous, but usually dry gaseous carbon dioxide is applied to 1 mol of the organolithium compound under a pressure of 1 to 10 kg / cm ² (gauge pressure). 0.5-100 mol are fed into the polymer solution and reacted. The obtained terminal carboxylithium-containing polymer is carboxylated by the addition of a proton donor. As a proton donor,
Water, inorganic acids, organic acids and alcohols are used.

The amount of the proton donor added is usually 1 to 2 times the molar amount of the organic lithium compound. The polymer having a carboxyl group at the terminal produced by the method of the present invention has, for example, the general formula:

[0026]

[Chemical 1] (In the formula, B is a conjugated diene-based polymer or a block component thereof, or a random copolymer of a conjugated diene and an aromatic vinyl compound or a block component thereof, and has a tapered block in which the proportion of the vinyl aromatic compound gradually increases. A represents a polymer block mainly containing an aromatic vinyl compound, the content of the aromatic vinyl compound is 10 to 80% by weight, and the weight average molecular weight of the polymer is 10,000 to 1,000.
10,000, vinyl bond of conjugated diene polymer part is 1
It is 0 to 80% by weight. Here, n is an integer of 1 to 3. ) Is a structure represented by.

Further, a hydrogenated carboxyl group-containing polymer can be produced by saturating the double bond of these polymers using a known hydrogenation method.
The conjugated diene-based polymer having a carboxyl group at the terminal produced by the present invention utilizes the reactivity of the carboxyl group at the terminal to synthesize a graft polymer or a block polymer, an adhesive, a coating material, a molding material. It is useful as a raw material such as an asphalt modifying material, and as a rubber used to obtain a styrene resin (HIPS, ABS, etc.) having impact resistance.

[0028]

EXAMPLES Hereinafter, specific examples of the present invention will be shown by some examples, but this is for more specifically explaining the gist of the present invention and does not limit the present invention. .. Various measurements were made by the following methods. [Microstructure] Using an infrared spectrophotometer, polybutadiene was analyzed by the Morello method [La chimica EL'industria 41 , 758 (19
58)], for the styrene-butadiene copolymer, the Hampton method [Analytical Chemistry, 21 , 923 (194
9)].

[Content of Carboxyl Group in Polymer] After washing the polymer with a large amount of water to remove hydrogen chloride and catalyst residues, a 1/20 normal standard alcohol solution of potassium hydroxide was used to It was determined by performing a Japanese titration. [Weight Average Molecular Weight] Using GPC manufactured by Waters Co.,
The column was a column manufactured by DuPont, and the weight-average molecular weight in terms of polystyrene was calculated from the GPC curve measured at 35 ° C.

(Examples 1 to 14) An autoclave equipped with a stirrer and a jacket having an internal volume of 10 L was washed and dried,
After purging with nitrogen, 1,3-butadiene previously purified and dried, a hydrocarbon solvent and optionally styrene are added, and then tetrahydrofuran as a 1,2-vinyl modifier is added, and an organolithium initiator is further added. As a solution, a 5% by weight solution of n-butyllithium in n-hexane is added to 70 ° C.
Polymerization was started at. The polymerization temperature was raised to about 100 ° C to obtain a living polymer solution.

Then, a Lewis base was added to this living polymer, and carbon dioxide gas dried at the temperature shown in Table 1 was fed at 5 kg / cm ² (gauge pressure) for 10 minutes. Further, an aqueous sulfuric acid solution was added in an amount 1.5 times the molar amount of the polymerization initiator used for living polymerization, and the reaction was carried out for 30 minutes.
After the reaction solution was once transferred to a SUS container having an internal volume of 18 L, 10 L of pure water was added and washed with water for 30 minutes, and then water was extracted, and this operation was repeated twice to remove excess sulfuric acid.

2,6-di-tert-butyl-4-methylphenol (BHT) was added as a stabilizer to the polymer solution thus obtained in an amount of 0.5 per 100 parts by weight of the polymer.
By weight, the solvent was removed by heating to obtain carboxyl group-containing polybutadiene rubbers shown in Tables 1 and 2. The by-product ratio (%) is a value calculated by the following formula from the curve obtained by GPC as shown in FIG.

[0033]

[Equation 1] A ₁ : Area obtained from GPC curve of main product A ₂ : Area obtained from GPC curve of by-products (dimer and trimer or more)

(Example 15) An autoclave equipped with a stirrer and a jacket having an internal volume of 10 L was washed and dried, and after purging with nitrogen, 5,000 g of cyclohexane, 1.2 g of tetrahydrofuran and 120 g of styrene were charged, and hot water was passed through the jacket. Then, the contents were set to about 70 ° C. After that, an n-butyllithium cyclohexane solution (1.0 g in pure content) was added to initiate polymerization of styrene. 10 minutes after the styrene was completely polymerized, 560 g of 1,3-butadiene was added and the polymerization was continued, and after the butadiene was almost completely polymerized and the maximum temperature (95 ° C) was reached, 15
After 120 minutes, 120 g of styrene was added again to continue the polymerization, and after the styrene was almost completely polymerized, it was held for another 15 minutes to complete the polymerization, and then TMEDA was added to 2,000.
5 kg / cm of dry carbon dioxide added with ppm
² (gauge pressure) was fed for 10 minutes. The temperature at this time was 90 ° C.

Further, an aqueous sulfuric acid solution was added in an amount 1.5 times the molar amount of the polymerization initiator used for living polymerization, and the reaction was carried out for 30 minutes. After the reaction solution was once transferred to a SUS container having an internal volume of 18 L, 10 L of pure water was added and washed with water for 30 minutes, and then water was extracted, and this operation was repeated twice to remove excess sulfuric acid. To the polymer solution thus obtained, 0.5 part by weight of 2,6-di-tert-butyl-4-methylphenol (BHT) was added as a stabilizer per 100 parts by weight of the polymer, and the solvent was removed by heating to give a mixture shown in Table 1 To obtain a carboxyl group-containing block copolymer.

[0036]

[Table 1]

[0037]

[Table 2]

Note) n-butyllithium: 5% by weight of butyllithium in n-hexane solution C: cyclohexane, N: n-hexane, TMEDA: N, N, N ', N'-tetramethylethylenediamine, DME: 1,2-dimethoxyethane, DMTA: 1,1-dimethoxytrimethylamine, TEA: triethylamine

(Comparative Examples 1 to 6) Solvents and Lewis bases are shown in Table 3.
Example 1 was carried out in the same manner as in Example 1 except that the kind and the addition amount were shown. The results are shown in Table 3.

[0040]

[Table 3]

Note) n-butyllithium: 5% by weight of butyllithium in n-hexane solution BENZ: benzene, C: cyclohexane, TMEDA: N, N, N ', N'-tetramethylethylenediamine,

(Examples 16 to 28) Next, an organolithium-based catalyst, which is a reaction product containing at least a monoorganolithium compound and a polyvinylaromatic compound, was prepared, and this was used to terminate the active lithium terminal. A living polybutadiene having the above was obtained. Table 4 shows a method for preparing the organolithium-based catalyst.

[0043]

[Table 4] (Catalyst preparation ratio) (Note) * Divinylbenzene / n-butyllithium (molar ratio) The catalyst prepared by the method of Table 4 is soluble in n-hexane, and divinylbenzene contains 57% by weight of the isomer mixture, the balance being Commercially available divinylbenzene consisting of ethylvinylbenzene and diethylbenzene was used.

Carboxyl group-containing polybutadienes shown in Tables 5 to 6 were obtained in the same manner as in Example 1, except that the two kinds of organolithium-based catalysts thus obtained were used. The by-product ratio (%) is a value calculated by the following equation 2 as shown in FIG.

[0045]

[Equation 2] B ₁ : Area of main polymer before reaction with carbon dioxide determined from GPC curve B ₂ : Area of high molecular weight portion before reaction with carbon dioxide determined from GPC curve B ₃ : Carbon dioxide determined from GPC curve area B ₄ of the major product after the reaction: the area of the high molecular weight fraction after reaction with carbon dioxide determined by GPC curve

[0046]

[Table 5]

[0047]

[Table 6]

Note) The amount of the organolithium-based catalyst used is n-
The amount is shown in terms of butyllithium equivalent. C: cyclohexane, N: n-hexane, TMEDA: N, N, N ', N'-tetramethylethylenediamine, DME: 1,2-dimethoxyethane, DMTA: 1,1-dimethoxytrimethylamine, TEA: triethylamine

[0049]

EFFECTS OF THE INVENTION According to the present invention, a conjugated diene-based copolymer having a carboxyl group at the polymer terminal can be produced extremely efficiently under industrially advantageous temperature conditions. large. The use of the carboxyl group-containing conjugated diene-based copolymer of the present invention covers a wide range of areas, such as polystyrene resin, ABS resin modifiers, adhesives, asphalt modifiers, coating materials, molding materials, etc. It is useful as a raw material.

[Brief description of drawings]

FIG. 1 is a GPC curve of a carboxyl group-containing polybutadiene rubber obtained in Example 11.

2 is a GPC curve obtained before and after the reaction with carbon dioxide obtained in Example 19. FIG.

Claims (1)

[Claims] 1. At least one conjugated diene-based monomer is polymerized with at least one copolymerizable monomer, optionally in a hydrocarbon solvent, using an organolithium compound as an initiator. In the method for producing a carboxyl group-containing polymer by reacting the living polymer thus obtained with carbon dioxide in the presence of a Lewis base, (A) the hydrocarbon solvent is an aliphatic hydrocarbon. Or at least one solvent selected from alicyclic hydrocarbons, (B) the Lewis base is a tertiary monoamine, a tertiary diamine, a chain ether having two or more oxygen atoms in one molecule, or At least one compound selected from cyclic ethers, wherein the Lewis base is used in the hydrocarbon solvent.
A method for producing a carboxyl group-containing conjugated diene polymer, wherein the presence of 0 to 5,000 ppm (C) the reaction temperature of the living polymer and carbon dioxide is in the range of 50 to 140 ° C.