JP2003137917A - Method for producing vinylester-based polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for industrially easily producing a vinylester- based polymer by accurately controlling its primary structure i.e., accurately controlling its molecular weight and molecular weight distribution. SOLUTION: This method comprises polymerizing a vinylester-based monomer in the presence of a living radical polymerization initiator system comprising a transition metal complex, an organic halide and a Lewis acid.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a vinyl ester polymer while precisely controlling the primary structure. More specifically, the present invention relates to a method for producing a vinyl ester polymer in the presence of a specific living radical polymerization initiator system while controlling the molecular weight and the molecular weight distribution precisely.

[0002]

2. Description of the Related Art The production of vinyl polymers utilizing radical polymerization has long been carried out on an industrial scale as a method for producing various polymers such as polyvinyl acetate. In the case of the conventional production method, the growing radical in a series of radical polymerization reactions is inactivated by recombination, a termination reaction such as disproportionation, or a side reaction such as chain transfer, so that the resulting vinyl-based polymer is The molecular weight distribution was wide, and it was difficult to control the molecular weight of the polymer, control the molecular ends of the polymer, and synthesize the block polymer.

The living radical polymerization method has been attracting attention as a measure for solving the technical problems in these conventional manufacturing methods. If living radical polymerization is used, it becomes possible to control the molecular weight, the molecular weight distribution, the molecular ends, etc., and to obtain a block polymer. In particular, many studies have been conducted on monomers such as styrene, methacrylate and acrylate, and it is known that the primary structure of the polymer can be controlled with a certain degree of precision.

However, since vinyl ester type monomers such as vinyl acetate have a very large chain transfer constant, chain transfer is more likely to occur as compared with styrene and methacrylate, and further, the resonance stabilizing effect of electrons is low and a growing radical. Is very unstable, and side reactions easily occur, and there are very few examples of successful living radical polymerization of vinyl ester-based monomers.

Regarding the precise control of the primary structure of the polymer in the radical polymerization, styrene monomer is described in the reference Macr.
omolecules, 33, 3543 (2000), for acrylic monomers, see Polymer Preprints, Japan, 50, 106 (200
In 1), by using a radical polymerization initiator system consisting of an organic halide having a carbon-iodine bond and a transition metal complex having iron as a central metal, it is described that a polymer having a narrow molecular weight distribution can be obtained. is there. However, there is no report on vinyl ester monomers in these documents.

So far, regarding living radical polymerization of vinyl ester monomers, triisobutylaluminum, 2,2'-dipyridyl and 2,2,6,6-tetramethyl-1-piperidinyloxy compound (TEMP) have been used.
A method using a three-component initiator system of O) has been proposed (Macromolecules, 27, 645 (1994)). However, since this initiator system is extremely unstable to water and oxygen, the reproducibility of polymerization is impaired by the presence of a trace amount of water and oxygen, and it is not suitable for an industrial production method.

A method using an initiator system composed of two components of 2,2'-azobis (isobutyronitrile) and N, N-diethyldithiocarbamate has also been proposed (Macrom).
ol. Rapid. Commun., 21, 1035 (1994)). However, in the case of vinyl ester-based monomers, it is necessary to use a large amount of 2,2′-azobis (isobutyronitrile) as compared with acrylates and methacrylates, and polymerization using this initiator system is also industrially possible. It is not the preferred method.

A method using an initiator system consisting of two components of 2,2'-azobis (isobutyronitrile) and an iodine compound has also been proposed (JP-A-10-60221). However, a large amount of 2,2'-azobis (isobutyronitrile) is required with respect to the iodine compound that becomes the polymerization initiation terminal, and the polymerization using this initiator system is not an industrially preferable method.

[0009]

The object of the present invention is to solve the conventional technical problems and to precisely control the primary structure of a vinyl ester polymer, that is, to precisely control its molecular weight and molecular weight distribution. However, it is to provide a method for industrially easily producing a vinyl ester polymer.

[0010]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that in the presence of an initiator system composed of a specific transition metal complex, an organic halide and a Lewis acid, It was found that a vinyl ester polymer having a narrow molecular weight distribution can be obtained by polymerizing a vinyl ester monomer, and the present invention has been completed.

That is, the present invention provides the following component (A),
(B) and (C): (A) transition metal complex; (B) organic halide; and (C) Lewis acid, in the presence of a living radical polymerization initiator system, a vinyl ester system having 3 to 20 carbon atoms. The monomer (D) is polymerized, and the ratio Mw of the weight average molecular weight Mw and the number average molecular weight Mn.
Provided is a method for producing a vinyl ester polymer, which comprises obtaining a vinyl ester polymer having / Mn in the range of 1.1 to 2.0.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

In the method for producing a vinyl ester polymer of the present invention, a transition metal complex (component (A)), an organic halide (component (B)) as a polymerization initiator, and a Lewis acid (component (component (B)) are used. The vinyl radical monomer is polymerized using a living radical polymerization initiator system consisting of C)).

In the present invention, as the central metal constituting the transition metal complex of the component (A) constituting the living radical polymerization initiator system, iron, molybdenum, ruthenium, rhodium, nickel, copper, etc. can be used. ~ Group 11 elements (edited by The Chemical Society of Japan "Chemical Handbook Basic Edition I Revised 4th Edition" (1993
Year)) according to the periodic table) is preferable, and iron and molybdenum are particularly preferable.

Specific examples of the transition metal complex having iron as a central metal include iron (II) acetate, dicarbonylcyclopentadienyl iodoiron, iron (II) acetylacetonate, iron (II) phthalocyanine,
1,1'-diacetylferrocene, 1,1'-dimethylferrocene, dicarbonylcyclopentadienyl iron dimer, dicyclopentadienyl iron, tricarbonyl (cyclooctatetraene) iron and the like, among which dicarbonylcyclo Pentadienyl iron dimer is preferred.

Specific examples of the transition metal complex containing molybdenum as a central metal include molybdenum hexacarbonyl, molybdenum (II) acetate dimer, [1,1'-bis (diphenylphosphino) ferrocene] tetracarbonyl molybdenum, [1, 2-bis (diphenylphosphino) ethane] tetracarbonylmolybdenum, (bicyclo [2.2.1] hepta-2,5-diene) tetracarbonylmolybdenum, (propylcyclopentadienyl)
Molybdenum tricarbonyl dimer, cis-tetracarbonylbis (piperidine) molybdenum, cyclopentadienyl molybdenum tricarbonyl halide, cyclopentadienyl molybdenum tricarbonyl dimer, dicarbonyl (pentamethylcyclopentadienyl) molybdenum dimer, methylcyclopentadiene Examples thereof include enyl molybdenum tricarbonyl dimer, triamine molybdenum tricarbonyl, tricarbonyl (cycloheptatriene) molybdenum, and the like, of which cyclopentadienyl molybdenum tricarbonyl dimer is preferable.

In the present invention, the organic halide of the component (B) constituting the living radical polymerization initiator system functions as a polymerization initiator. Examples of such organic halides include products obtained by addition reaction of hydrogen iodide and alkenes, iodomethane, iodoethane, iodopropane, iodobutane, diiodomethane, 1,2-diiodoethane, iodoform, chloroiodomethane, iodoacetonitrile, iodoacetic acid. , 1,6-diiodohexane, iodoacetamide and the like, among which the product of the addition reaction between hydrogen iodide and an alkene is preferable.

Specific examples of the alkenes include vinyl ester type monomers such as vinyl acetate; methyl methacrylate,
Examples thereof include methacrylic acid ester-based monomers such as ethyl methacrylate; acrylic acid ester-based monomers such as methyl acrylate.

The amount of the organic halide as the component (B) is appropriately determined according to the molecular weight of the target polymer, but if the amount of the organic halide is too small, the primary structure of the polymer will be controlled. It becomes difficult, and if it is too much, it becomes difficult to obtain a polymer, so it is preferable to add it in a ratio of 0.00015 to 0.2 mol per 1 mol of the vinyl ester monomer, and 0.0005 to 0.1 More preferably, it is added in a molar ratio.

In the present invention, the Lewis acid as the component (C) constituting the living radical polymerization initiator system functions as an activator. Examples of such a Lewis acid include aluminum trialkoxides such as aluminum triisopropoxide and aluminum tri (t-butoxide); bis (2,6-di-t-butylphenoxy) methylaluminum, bis (2,4,4). Bis (substituted aryloxy) alkyl aluminum such as 6-tri-t-butylphenoxy) methyl aluminum; Tris (substituted aryloxy) aluminum such as tris (2,6-diphenylphenoxy) aluminum; Titanium such as titanium tetraisopropoxide Examples of the tetraalkoxide include trialkylaluminums such as triisobutylaluminum, and among them, aluminum triisopropoxide, titanium tetraisopropoxide, and triisobutylaluminum are preferable. These may be used alone or in combination of two or more.

In the present invention, the content ratio of each component in the living radical polymerization initiator system is not necessarily limited, but if the ratio of the component (A) to the component (B) is too small, the polymerization becomes slow. If the amount is too large, the molecular weight distribution of the resulting polymer tends to widen. Therefore, the molar ratio of component (A) / component (B) is within the range of 0.05 / 1 to 3/1. Preferably there is. Further, when the ratio of the component (C) to the component (B) is too small, the polymerization tends to be slow, and conversely, when the ratio is too large, the molecular weight distribution of the obtained polymer tends to be broad,
The molar ratio of component (B) / component (C) is 1 / 0.05 to 1 /
It is preferably within the range of 5.

The living radical polymerization initiator system used in the present invention usually comprises a transition metal complex of component (A), an organic halide of component (B) and component (C) immediately before use.
It can be prepared by mixing the Lewis acid. Further, the transition metal complex of the component (A), the organic halide of the component (B) and the Lewis acid of the component (C) are stored separately and added separately to the polymerization reaction system to You may make it function as a living radical polymerization initiator system by mixing in it.

In the present invention, the vinyl ester monomer (D) having 3 to 20 carbon atoms used for polymerization includes, for example, vinyl acetate, vinyl pivalate, vinyl formate, vinyl propionate, vinyl butyrate, n-vinyl caproate, vinyl isocaproate, vinyl octanoate, vinyl laurate, vinyl palmitate, vinyl stearate, vinyl trimethyl acetate, vinyl chloroacetate, vinyl trichloroacetate, vinyl trifluoroacetate, vinyl benzoate and the like. These may be used alone or in combination of two or more. Among these, vinyl acetate and vinyl pivalate are preferable.

In addition, as long as the effects of the present invention are not impaired,
Monomers other than vinyl ester-based monomer (D), for example,
(Meth) acrylic acid; methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, (meth) acrylic acid Isobutyl, sec-butyl (meth) acrylate, t (meth) acrylic acid
ert-butyl, n-hexyl (meth) acrylate,
Cyclohexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate,
2-Ethylhexyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, (meth)
(Meth) acrylic ester monomers such as isobornyl acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate, stearyl (meth) acrylate, dimethylaminoethyl (meth) acrylate; styrene, α-methylstyrene , P-methylstyrene, m-methylstyrene, o-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, p-ethylstyrene, p-isopropylstyrene, p-chloromethylstyrene, p- (2 It is also possible to use a styrene-based monomer such as -chloroethyl) styrene and the vinyl ester-based monomer (D) in combination and copolymerize them.

In the present invention, a living radical polymerization initiation comprising a transition metal complex (component (A)), an organic halide (component (B)) as a polymerization initiator, and a Lewis acid (component (C)) as an activator. A vinyl ester polymer is obtained by radically polymerizing the vinyl ester monomer (D) in the presence of an agent system. The vinyl ester monomer (D) may be added to the polymerization solution in the total amount from the beginning, or may be sequentially added as the polymerization progresses.

The vinyl ester polymer obtained by the production method of the present invention has a molecular weight of 500 to 500,000 (number average molecular weight) because if it is too small, the function as a polymer is difficult to develop and if it is too large, handling becomes difficult. ) Is preferable, and 1,000 to 200,000 (number average molecular weight) is more preferable. Here, the molecular weight of the vinyl ester polymer can be adjusted by adjusting the concentration of the organic halide of the component (B) contained in the living radical polymerization initiator system. Specifically, by increasing the concentration of the organic halide, it is possible to reduce the molecular weight of the vinyl ester-based polymer, and conversely, by reducing the concentration of the organic halide, the vinyl ester-based polymer The molecular weight can be increased.

As the polymerization method used in the production method of the present invention, a conventionally known method can be used, and examples thereof include a bulk polymerization method, a solution polymerization method, a suspension polymerization method and an emulsion polymerization method. Among them, the solution polymerization method or the bulk polymerization method having a very high vinyl ester monomer concentration is preferably used from the viewpoint of reducing chain transfer and controlling the polymerization more precisely. In the solution polymerization method, the concentration of the vinyl ester monomer (D) is preferably 20% by weight or more, more preferably 30% by weight or more. Further, the polymerization may be continuously carried out using an extruder.

When the solution polymerization method is adopted, alcohols, toluene, benzene, anisole, ethyl acetate and the like can be mentioned as the solvent. Especially, the chain transfer constant is relatively small during the polymerization of vinyl ester type monomers. Preferred are anisole, benzene and ethyl acetate, which are also excellent in polymer solubility.

In the production method of the present invention, at the start of the polymerization reaction, the monomer (D), the solvent, the Lewis acid (component (C)), the transition in the reaction vessel under an atmosphere of an inert gas such as nitrogen. It is preferable to prepare a mixture of a metal complex (component (A)) and an internal standard substance for gas chromatography measurement, and add a polymerization initiator (component (B)) to the mixture. And the mixture thus obtained,
The polymerization can be initiated by heating to a temperature usually in the range of 10 to 120 ° C, preferably 25 to 100 ° C.

After the completion of the polymerization, for example, the polymerization reaction system is cooled to 0 ° C. or lower, preferably about −78 ° C. to stop the reaction, then diluted with a solvent such as toluene or anisole, and then added to n-hexane. Then, the precipitate is washed several times and dried under reduced pressure at room temperature to obtain the intended vinyl ester polymer.

In the living radical polymerization of the present invention, the carbon-halogen bond in the organic halide of the component (B) is activated by the transition metal complex of the component (A) and the Lewis acid of the component (C), and the bond is formed. Polymerization proceeds with a vinyl ester monomer being inserted therein. This type of progress of polymerization is also supported by the fact that most of the growing terminals of the obtained vinyl ester polymer are halogen elements. Therefore, by using an organic halide having a functional group as the component (B), it is possible to introduce a functional group into the starting terminal of the target vinyl ester polymer. Further, it is possible to convert the halogen element at the growing end into another functional group by utilizing the reactivity of the halogen element at the growing end.

The terminal functional group thus introduced into the desired vinyl ester polymer can be utilized for the synthesis of macromonomers, the synthesis of block copolymers, the crosslinking point and the like. Further, the block copolymer thus obtained exhibits novel physical properties that cannot be obtained by a homopolymer. For example, diblock copolymers are useful as compatibilizers and the like, and triblock copolymers such as ABA type are useful as thermoplastic elastomers and the like.

[0033]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

In the following Examples and Comparative Examples,
Unless otherwise specified, all the operations were performed under a dry nitrogen gas atmosphere, and the reagents were collected from the container by a syringe and added to the reaction system. The solvent and the monomer used were those purified by distillation and further blown with dry nitrogen gas.

The polymerization rate of the polymer is determined by gas chromatography (internal standard: n-
Octane), and calculated based on the analysis value.
The values of the number average molecular weight (Mn), the weight average molecular weight (Mw) and the molecular weight distribution (Mw / Mn) of the obtained polymer were measured under the following conditions using gel permeation chromatography (GPC). And calculated in terms of polymethylmethacrylate.

Column: Showdex K-805L (3 in series) manufactured by Showa Denko KK Solvent: Chloroform Temperature: 40 ° C. Detector: RI and UV Flow rate: 1 ml / min

Reference Example (Production of hydrogen iodide adduct of ethyl methacrylate) 122 g of sodium iodide (manufactured by Wako Pure Chemical Industries, Ltd.) was weighed and put into a three-necked flask which was replaced with argon, and after sufficiently dried, 500 ml of acetone was added to dissolve sodium iodide, 25 ml of ethyl 2-bromoisobutyrate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the resulting solution, and the mixture was reacted at 65 ° C. for 24 hours.

After filtering the obtained reaction product, distilled water and diethyl ether were added to the filtrate, and only the organic layer was extracted using a separating funnel. The obtained organic layer was washed successively with an aqueous sodium thiosulfate solution, an aqueous sodium chloride solution and distilled water, and then only the organic layer was extracted and dried under reduced pressure. The obtained reaction product was further purified by vacuum distillation,
The product was dried under reduced pressure under the condition of 1.33 × 10 ³ Pa to obtain the intended hydrogen iodide adduct of ethyl methacrylate.

Example 1 Using anisole as a solvent, the hydrogen iodide adduct of ethyl methacrylate was 40 mmol / l, and dicarbonylcyclopentadienyl iron dimer (manufactured by Aldrich) was 2
0 mmol / l, aluminum triisopropoxide (manufactured by Aldrich) 20 mmol / l, vinyl acetate monomer (manufactured by Wako Pure Chemical Industries, Ltd.) 8 mol / l, n-octane (manufactured by Wako Pure Chemical Industries, Ltd.) 0.31 mol The resulting mixture was uniformly mixed to give a polymerization reaction solution of 0.6 ml, and each 0.6 ml of the polymerization reaction solution was dispensed and sealed in a test tube and heated to 60 ° C. to start polymerization. After reacting for 27 hours, the polymerization solution was cooled to −78 ° C. to stop the polymerization.

When the vinyl acetate monomer in the obtained reaction solution was analyzed by gas chromatography using n-octane as an internal standard, the polymerization rate of vinyl acetate was 56%.
Met. Moreover, after diluting the obtained reaction solution with anisole, it is put into n-hexane to precipitate the polymer,
After washing several times with n-hexane, it was dried under reduced pressure at room temperature to obtain polyvinyl acetate. The molecular weight and molecular weight distribution of the obtained polyvinyl acetate were determined by gel permeation
When measured by chromatography, Mn = 108
00, Mw = 20200, and Mw / Mn = 1.87.

Examples 2 to 15 and Comparative Examples 1 to 3 Predetermined amounts of monomers, iodine compounds shown in Tables 1 and 2,
Using a transition metal complex, a Lewis acid, a solvent, an internal standard substance and the like, a polymerization reaction solution was prepared in the same manner as in Example 1, and polymerization was carried out at the temperatures and reaction times shown in Tables 1 and 2. The obtained polymerization solution was treated for gas chromatography in the same manner as in Example 1 and then treated in the same manner as in Example 1 to obtain a polymer, and the molecular weight and the molecular weight of the obtained polymer were determined. The molecular weight distribution was measured. These measurement results are shown in Table 1.
And shown in Table 2.

As can be seen from Tables 1 and 2, in the living radical polymerization initiator system, Comparative Example 1 lacking the transition metal complex of the component (A) did not cause any polymerization reaction. Further, in the case of Comparative Example 2 which lacks the organic halide of the component (B) among the living radical polymerization initiator systems, no polymerization reaction occurred at all. Among the living radical polymerization initiator systems, Comparative Example 3 lacking the Lewis acid as the component (C) had a very slow polymerization reaction rate and a wide molecular weight distribution. It was impossible to control.

On the other hand, in the case of Examples 1 to 15,
Since the living radical polymerization initiator system is composed of the components (A), (B) and (C), the polymerization rate is very high as compared with the case of the polymerized Comparative Example 3, and the obtained polymer is The molecular weight distribution was 2 or less, which was a very narrow range. Further, it is understood that the molecular weight can be controlled by controlling the compounding amount of the organic halide of the component (B).

[0044]

[Table 1]

[0045]

[Table 2]

[0046]

According to the production method of the present invention, the vinyl ester-based polymer is precisely controlled in its primary structure,
That is, it can be easily produced industrially while controlling its molecular weight and molecular weight distribution precisely.

Continued front page    (72) Inventor Mitsuo Sawamoto             920-23 Haramachi, Shizu City, Sakyo Ward, Kyoto City, Kyoto Prefecture (72) Inventor Masami Uegaki             Kyoto Prefecture Kyoto City Sakyo Ward Shugakuin Noboricho 11-50               Fragrance Hiay View Building B No. 203 (72) Inventor Tsuyoshi Ando             26-8 Rengekuracho, Shogoin, Sakyo-ku, Kyoto-shi, Kyoto Prefecture             Hoshi Mansion No. 31 (72) Inventor Shiro Kyoretsu             71 Rene Ichijoji Tsukita-cho, Sakyo-ku, Kyoto-shi, Kyoto Prefecture             Shirakawa 101 (72) Inventor Masayuki Wakioka             14-3 Kitanoshirakawayamanomotomachi, Sakyo-ku, Kyoto-shi, Kyoto Prefecture               Rafine Kitashirakawa Building A No. 101 F-term (reference) 4J015 CA00

Claims (7)

[Claims] 1. The presence of a living radical polymerization initiator system comprising the following components (A), (B) and (C): (A) transition metal complex; (B) organic halide; and (C) Lewis acid. Under the conditions below, the vinyl ester monomer (D) having 3 to 20 carbon atoms is polymerized, and the ratio Mw of the weight average molecular weight Mw and the number average molecular weight Mn.
A method for producing a vinyl ester polymer, wherein a vinyl ester polymer having / Mn in the range of 1.1 to 2.0 is obtained. 2. The transition metal complex of component (A) is a transition metal complex having iron or molybdenum as a central metal.
The manufacturing method described. 3. The production method according to claim 2, wherein the transition metal complex as the component (A) is a dicarbonylcyclopentadienyl iron dimer containing iron as a central metal. 4. The method according to claim 2, wherein the transition metal complex of the component (A) is a tricarbonylcyclopentadienyl molybdenum dimer containing molybdenum as a central metal. 5. The production method according to claim 1, wherein the halogen in the organic halide of the component (B) is iodine. 6. The production method according to claim 1, wherein the Lewis acid as the component (C) is at least one selected from aluminum trialkoxide, titanium tetraalkoxide and trialkylaluminum. 7. The method according to claim 1, wherein the vinyl ester-based monomer (D) is vinyl acetate and / or vinyl pivalate.