JP2000044631A - Production of acrylic ester polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a high polymerization rate compatible with living properties and smoothly produce an acrylic ester polymer having a narrow distribution of molecular weight and useful as an adhesive, a coating material, etc., with good reproducibility by using an organolithium compound and a specific organoaluminum compound. SOLUTION: An acrylic ester (e.g. a primary alkyl ester of acrylic acid) is polymerized in the presence of (B) an organolithium compound such as sec- butyllithium or 1,3-bis(lithio-1,3-dimethylpentyl)benzene and (C) a compound represented by the formula: AlR1R2R3 [R1 is a >=3C (substituted)alkyl, a >=3C (substituted) alkoxy or a (substituted) aryloxy, e.g. a 3-12C branched alkyl or a 4-12C linear alkyl; R2 and R3 are each a (substituted) aryloxy or R2 and R3 are bound to denote a (substituted) arylenedioxy].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an acrylate polymer. More specifically, an acrylic acid ester, particularly a primary alkyl acrylate, can be polymerized by an anionic polymerization method while achieving both a high polymerization rate and a high living property, so that acrylic acid having a desired molecular weight and a narrow molecular weight distribution is obtained. An ester polymer, especially a primary alkyl acrylate polymer,
The present invention relates to a method that can be smoothly manufactured with good reproducibility.

[0002]

2. Description of the Related Art The following reports (1) and (2) have been made on a method for producing an acrylate polymer by anionic polymerization of an acrylate ester.

(1) Using an organolithium compound as a polymerization initiator and lithium 2- (2-methoxyethoxy) ethoxide as an additive, an acrylate ester is mixed in a mixed solvent of toluene and tetrahydrofuran at -78 ° C or the like. Solution polymerization under low temperature conditions gives acrylate polymers (Macromolecules Vol. 27, 4890-4895).
Page, 1994; Journal of Polymer Science: Part A: Po
lymer Chemistry Vol. 35, pp. 361-369, 1997, etc.).

(2) Using t-butyllithium as a polymerization initiator, methylbis (2,6-di-t-butylphenoxy)
Using aluminum or ethyl bis (2,6-di-t-butylphenoxy) aluminum as an additive, the acrylate ester is dissolved in toluene at -60 ° C or -78 ° C.
Acrylic acid ester polymer can be obtained by solution polymerization under the temperature condition of ℃ (Polymer Prep.
rints, Japan) Volume 46, Issue 7, Pages 1081 to 1082 (1997
Vol. 47, No. 2, p. 179 (1998)).

[0005] On the other hand, the following (3) to (6) reports have been made on anionic polymerization of methacrylic acid esters, but not on the method for producing acrylic acid ester polymers.

(3) When methyl methacrylate is solution-polymerized in toluene using t-butyllithium as a polymerization initiator and trialkylaluminum as an additive, a polymethyl methacrylate having a syndiotacticity of 80% or more is obtained. (Makromol. Chem., Supplement No. 15)
167-185 (1989)).

(4) Solution polymerization of methyl methacrylate in toluene in the presence of diisobutyl (2,6-di-t-butyl-4-methylphenoxy) aluminum using t-butyllithium as a polymerization initiator Produces polymethyl methacrylate with a syndiotacticity of about 70% (Macromolecules Vol. 25, pp. 5907-5913 (1992)
Year)).

(5) A specific organic aluminum compound having one or more bulky groups (eg, triisobutylaluminum, diisobutyl (2,6-di- tert-butyl-4-methylphenoxy) aluminum, etc.) as an additive to convert methacrylic acid esters from -20 ° C to +
When polymerized at a temperature within the range of 60 ° C., a methacrylate polymer having a narrow molecular weight distribution is produced (Japanese Patent Application Laid-Open No. Hei 5-
No. 5009).

(6) The organolithium compound initiator is methyl bis (2,6-di-t-butylphenoxy) aluminum, ethylbis (2,6-di-t-butylphenoxy) aluminum, isobutylbis (2,6- Di-t-
After mixing with a ligand such as butylphenoxy) aluminum and tris (2,6-di-t-butylphenoxy) aluminum at a temperature of 0 ° C. or more, the mixture is brought into contact with methyl methacrylate to carry out anionic polymerization, thereby syndiotactically. Polymethyl methacrylate having a triad content of 70% or more can be obtained (JP-A-7-330819).

Incidentally, Japanese Patent Laid-Open Publication No.
No. 09 discloses an anionic polymerization method of a methacrylic acid ester in the presence of an organoaluminum compound having a bulky group, as described in the publication, applied to a monomer having an acrylic hydrogen atom. Describes that the polymerization reaction is suppressed.

[0011]

When anionic polymerization of a monomer is carried out industrially, a part of the polymerization initiator to be used has already been deactivated, and the polymerization initiator is mixed with the monomer, the solvent and the like. Further, it is not possible to completely avoid further deactivation of the polymerization initiator in the polymerization reaction system due to impurities such as water introduced into the polymerization reaction system. Therefore, even if anionic polymerization is performed using a polymerization initiator and a monomer in an amount theoretically calculated based on the target polymer molecular weight, a polymer having the target molecular weight can be produced with good reproducibility. I can't. When the living property in anionic polymerization is high, that is, when a living polymer having a long active anion life at the terminal is formed in the reaction system, the required amount theoretically calculated on the basis of the amount of the polymerization initiator is used. A small amount of monomer is used for polymerization to form a living polymer, the molecular weight of the living polymer is measured, and the number of moles of the living polymer is calculated based on the molecular weight and the amount of the monomer used. The amount of the monomer to be added is calculated based on the molecular weight and the number of moles of the polymer and the molecular weight of the target final polymer, and by polymerizing the additional amount of the monomer to the living polymer, It is possible to produce a polymer having a narrow molecular weight distribution having a high molecular weight with good reproducibility. On the other hand, when the living property in anionic polymerization is low, even if the above-described two-stage polymerization method is employed, the anion at the terminal of the polymer obtained in the first-stage polymerization is significantly deactivated with time. Second, the polymer obtained after the second-stage polymerization has a broad molecular weight distribution containing components having a lower molecular weight and higher components than the target molecular weight. In addition,
When the living property is low, deactivation proceeds even during the polymerization reaction, so that when the polymerization rate is relatively low, even in a one-stage polymerization operation, there is a problem that the molecular weight distribution of the obtained polymer is widened. .

Since the anionic polymerization of a monomer such as an acrylate ester generates heat, when this type of anionic polymerization is carried out on an industrial scale under cooling conditions, it is necessary to suppress the temperature rise of the polymerization reaction system due to the heat generation. It is extremely important. For this purpose, a method of continuously feeding a monomer at a predetermined rate to a reaction system and thereby controlling a polymerization rate may be adopted. However, when the polymerization reaction is carried out by continuously feeding the monomers, the high living property in the polymerization reaction tends to affect the uniformity of the molecular weight distribution of the obtained polymer. That is, if the living property is not so high, the obtained polymer has a broad molecular weight distribution.

In addition, after the anion polymerization, the resulting polymer having an active anion terminal is reacted with a terminal functionalizing agent to produce a polymer having a terminal functional group. In order to increase the rate, high living performance is required.

In the method (1) for producing an acrylate polymer, tetrahydrofuran is used as a part of the solvent in order to polymerize the acrylate ester with high living properties and to obtain a desired polymer in good yield. It is necessary. It is not easy to use or recover and purify tetrahydrofuran with high purity industrially because of its water absorption and mixing of peroxide. In addition, when a primary alkyl acrylate such as n-butyl acrylate is used as the acrylate, the polymerization may be carried out under extremely low temperature conditions of about -80 ° C in order to achieve high living properties. is necessary. As described above, the method (1) is difficult to apply to industrialization because it requires a solvent that is unsuitable for large-scale use in terms of handling, and requires a large cooling utility.

In the method (2) for producing an acrylate polymer, when the temperature of the polymerization system is very low, such as about -78 ° C., the polymerization rate is low and a long time is required. When the temperature of the polymerization system is a relatively high temperature of −60 ° C. or higher, the living property is reduced, so that the molecular weight distribution of the obtained polymer is widened or the two-stage polymerization method as described above. Makes it difficult to control the molecular weight. For these reasons, the method (2) is industrially disadvantageous.

In the case of anionic polymerization of methacrylic acid ester in the presence of an initiator system comprising an organic alkali metal compound and an organic aluminum compound as reported in the above (3) to (6), the organic aluminum compound Can suppress the side reaction of the anion of the growing species to the ester group of the methacrylic acid ester monomer, so that a methacrylic acid ester polymer having a narrow molecular weight distribution can be obtained. However, Japanese Patent Laid-Open Publication No.
No. 009 discloses that when an anionic polymerization method of methacrylic acid ester as described in the publication is applied to a monomer having an acrylic hydrogen atom, the polymerization reaction is suppressed. ing. The inventors of the present invention have attempted to divert some of the anionic polymerization methods for methacrylic acid esters to polymerization of acrylic acid esters, as described in (3) to (6) above, and as a result, have obtained good results. However, it was found that polymerization was particularly difficult in the case of primary alkyl acrylate. This is derived from the anion of the polymerization initiator and / or the growing species,
Arising from side reactions such as side reaction of the acrylate monomer to the ester group, extraction of the α-position proton of the acrylate monomer and the polymer, and attack on the ester group of the polymer it is conceivable that.

Accordingly, an object of the present invention is to provide an anionic polymerization method for polymerizing an acrylate such as a primary alkyl acrylate while achieving both a high polymerization rate and a high living property, and to obtain a molecular weight having a desired molecular weight. It is an object of the present invention to provide an industrially advantageous method capable of producing an acrylic ester polymer having a narrow distribution smoothly with good reproducibility.

[0018]

The present inventors have made various studies to achieve the above object, and as a result, when an initiator system is constituted by using a specific organoaluminum compound together with an organolithium compound, It has been found that the polymerization of acrylic acid ester can be carried out at a high reaction rate and at a high living property, and this effect is particularly remarkable in the case of polymerization of primary alkyl acrylate. Was.

That is, the present invention relates to a method for converting an acrylate ester into an organolithium compound and the following general formula (I):

[0020]

Embedded image AlR ¹ R ² R ³ (I)

(Wherein, R ¹ is an alkyl group having 3 or more carbon atoms which may have a substituent, and 3 carbon atoms which may have a substituent.
R ² and R ³ each independently represent an optionally substituted aryloxy group or an aryloxy group which may have a substituent;
^{And 2} and R ³ represent an arylenedioxy group which may have a substituent by bonding. )

A method for producing an acrylate polymer, characterized by polymerizing in the presence of an organoaluminum compound represented by the formula:

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

In the present invention, an organolithium compound and an organoaluminum compound represented by the above general formula (I) [hereinafter sometimes referred to as “organoaluminum compound (I)”]
It is necessary to polymerize the acrylate in the presence of

The organolithium compound used in the present invention is
Generally acts as a polymerization initiator. In the present invention, the type of the organolithium compound is not particularly limited, and can be generally used as long as it is an organolithium compound conventionally used as an anionic polymerization initiator in the polymerization of an anionic polymerizable monomer such as an acrylate ester. is there. Representative examples of the organolithium compound that can be used in the present invention include n-butyllithium, sec-
Alkyl lithiums such as butyllithium and t-butyllithium; aryllithiums such as fluorenyllithium and monoanion lithium salt based on α-methylstyrene oligomer; 1,1-diphenylhexyllithium;
Diphenylmethyllithium, 1,1-diphenyl-3-
Examples include aralkyl lithium such as methylpentyl lithium, trimethylsiloxylithium, and lithium ethyl isobutyrate. Examples of the bifunctional anionic polymerization initiator include tetra-α-methylstyrene dilithium, 1,3-bis (lithio-1, 3-dimethylpentyl) benzene,
1,3-bis (lithiophenyl-3-methylpentyl)
Examples thereof include organic dilithium compounds such as benzene. One of these organolithium compounds may be used alone, or two or more thereof may be used. Among the aforementioned organic lithium compounds, generally, sec-butyllithium, t-butyllithium, lithium ethylisobutyrate, 1,3-bis (lithio-1,3-dimethylpentyl) benzene, 1,3-bis ( (Lithiophenyl-3-methylpentyl) benzene and the like are preferably used from the viewpoint of polymerization initiation ability.

The organoaluminum compound (I) used in the present invention is a compound represented by the above general formula (I).

In the general formula (I), as described above, R ¹
Is an alkyl group having 3 or more carbon atoms which may have a substituent, an alkoxy group having 3 or more carbon atoms which may have a substituent, or an aryloxy group which may have a substituent. When R ¹ is an alkyl group having 1 or 2 carbon atoms (a methyl group or an ethyl group), it is difficult to achieve both a high reaction rate in polymerization and a high living property.

When R ¹ is an alkyl group which may have a substituent and has 3 or more carbon atoms, the organoaluminum compound (I) may have problems such as polymerization activity, handleability, ease of production, and availability. Is preferably an alkyl group having 3 to 12 carbon atoms, n-propyl group, isopropyl group, n
-Butyl group, isobutyl group, sec-butyl group, t-butyl group, 2-methylbutyl group, 3-methylbutyl group, n
-Octyl group, carbon number 3-10 such as 2-ethylhexyl, etc.
More preferably, it is an alkyl group. From the viewpoint of the stability of the active terminal of the polymer in the polymerization system and the high level of living property, among the alkyl groups having 3 or more carbon atoms, a branched alkyl group having 3 or more carbon atoms or a linear alkyl group having 4 or more carbon atoms. An alkyl group is preferable, and a branched alkyl group having 3 to 12 carbon atoms or a linear alkyl group having 4 to 12 carbon atoms is more preferable, and a branched alkyl group having 3 to 10 carbon atoms such as an isopropyl group, an isobutyl group, and a 3-methylbutyl group is preferred. A linear alkyl group having 6 to 10 carbon atoms such as a linear alkyl group or an n-hexyl group or an n-octyl group is more preferred. Among these, availability, handling, polymer growth terminal stabilization ability,
From the viewpoint of the living property and the like, it is particularly preferable that R ¹ is an isobutyl group.

When R ¹ is an optionally substituted alkoxy group having 3 or more carbon atoms, examples thereof include an isopropoxy group and a t-butoxy group.

When R ¹ is an aryloxy group which may have a substituent, phenoxy group, 2-methylphenoxy group, 4-methylphenoxy group, 2,6-dimethylphenoxy group, 2,4-di- t-butylphenoxy group, 2,6
-Di-t-butylphenoxy group, 2,6-di-t-butyl-4-methylphenoxy group, 2,6-diphenylphenoxy group, 1-naphthoxy group, 2-naphthoxy group, 9-
Unsubstituted aryloxy groups such as a phenanthryloxy group and a 1-pyrenyloxy group; and substituted aryloxy groups such as a 7-methoxy-2-naphthoxy group.

Incidentally, an alkyl group having 3 or more carbon atoms which may have a substituent represented by R ¹ , an alkoxy group having 3 or more carbon atoms which may have a substituent and an aryl which may have a substituent The oxy groups each have no substituents or one or more substituents. Examples of the substituent include an alkoxy group such as a methoxy group, an ethoxy group, an isopropoxy group and a t-butoxy group; and a halogen atom such as chlorine, bromine and fluorine.

In the general formula (I), R ² and R ³ each independently represent an aryloxy group which may have a substituent, or R ² and R ³ are bonded to each other as described above. It shows an arylenedioxy group which may have a substituent.

Preferred examples of the aryloxy group which may have a substituent represented by R ² and R ³ independently include a phenoxy group, a 2-methylphenoxy group, a 4-methylphenoxy group and a 2,6-dimethyl Phenoxy group, 2,
4-di-t-butylphenoxy group, 2,6-di-t-butylphenoxy group, 2,6-di-t-butyl-4-methylphenoxy group, 2,6-diphenylphenoxy group, 1
An aryloxy group having no substituent such as a naphthoxy group, a 2-naphthoxy group, a 9-phenanthryloxy group, and a 1-pyrenyloxy group; and an aryloxy group having a substituent such as a 7-methoxy-2-naphthoxy group. Can be mentioned. Preferred examples of the arylenedioxy group which may have a substituent represented by the combination of R ² and R ³ include 2,2′-diphenol, 2,2′-methylenebisphenol, and 2,2 ′ -Methylenebis (4-methyl-6
-T-butylphenol), (R)-(+)-1,1'-
Bi-2-naphthol, (S)-(−)-1,1′-bi-2-
Examples include groups derived from naphthol and the like.

An aryloxy group optionally having a substituent represented by R ² and R ³ independently and an arylenedioxy group optionally having a substituent represented by the combination of R ² and R ³ Have no substituents or have one or more substituents. Examples of the substituent include an alkoxy group such as a methoxy group, an ethoxy group, an isopropoxy group and a t-butoxy group; and a halogen atom such as chlorine, bromine and fluorine.

Further, when the organoaluminum compound (I) is 2
When it has an aryloxy group which may have one or three substituents, the aryloxy groups may have the same chemical structure, or may have different chemical structures.

Representative examples of the organoaluminum compound (I) used in the present invention include isobutyl bis (2,6-di-t-butyl-4-methylphenoxy) aluminum,
Isobutyl bis (2,6-di-t-butylphenoxy)
Aluminum, isobutyl [2,2'-methylenebis (4-methyl-6-t-butylphenoxy)] aluminum, n-octylbis (2,6-di-t-butyl-4)
-Methylphenoxy) aluminum, n-octylbis (2,6-di-t-butylphenoxy) aluminum,
n-octyl [2,2'-methylenebis (4-methyl-
6-t-butylphenoxy)] aluminum, tris (2,6-di-t-butyl-4-methylphenoxy) aluminum, tris (2,6-diphenylphenoxy)
Aluminum and the like can be given. Among these, in the general formula (I), R ¹ is an isobutyl group or n.
Octyl, and R ² and R ³ are each 2,
A compound corresponding to a 6-di-tert-butyl-4-methylphenoxy group or a 2,4-di-tert-butylphenoxy group, i.e., isobutylbis (2,6-di-t
-Butyl-4-methylphenoxy) aluminum, isobutylbis (2,4-di-t-butylphenoxy) aluminum, n-octylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum or n-octylbis (2,4-Di-t-butylphenoxy) aluminum is particularly preferred in terms of polymerization activity, ability to stabilize a polymer growth terminal, and the like.

The method for producing the organoaluminum compound (I) is not particularly limited. R ¹ has 3 carbon atoms which may have a substituent
Organoaluminum compound (I) when the above is an alkyl group or an aryloxy group which may have a substituent
Can be easily produced, for example, by reacting an aromatic compound having one or two phenolic hydroxyl groups in a molecule with trialkylaluminum in a predetermined ratio according to a known method. When R ¹ is an alkoxy group having 3 or more carbon atoms which may have a substituent, the organoaluminum compound (I) may be, for example, one alkyl group and two aryloxy groups according to a known method. A tertiary organoaluminum compound having (optionally having a substituent) or one arylenedioxy group (which may have a substituent) an alcohol having at least 3 carbon atoms in an approximately equimolar number. Can be easily produced by reacting at a ratio of

The amount of the organolithium compound used in the anionic polymerization according to the present invention is not necessarily limited, but the amount of the organolithium compound may be 0.01 to 10 mol based on 100 mol of the total monomers used. It is preferable to use the compound in a ratio falling within the range, since the intended acrylate polymer can be produced smoothly.

As to the ratio of the organolithium compound and the organoaluminum compound (I) to be used, a suitable ratio is appropriately selected according to the type of the polymerization method, the type of the polymerization solvent when performing the solution polymerization, and various other polymerization conditions. The organoaluminum compound (I) is generally used
Is preferably used in a ratio of at least 1.0 mol, more preferably at least 2.0 mol, per 1 mol of the organic lithium compound. Although there is no upper limit to the amount of the organoaluminum compound (I) used from the viewpoint of the polymerization reaction, the amount of the organoaluminum compound (I) used is reduced in view of production cost, removal of the residue of the organoaluminum compound contained in the polymer, and the like. Is preferably not more than 500 moles, more preferably not more than 100 moles, per mole of the organic lithium compound.

The type of the acrylate used in the present invention is not particularly limited, and any form may be used as long as it is composed of an acrylate component and an alcohol component. Specific examples of the acrylate ester that can be used in the present invention include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, Primary alkyl esters of acrylates such as cesyl acrylate and n-stearyl acrylate; glycidyl acrylate, allyl acrylate, 2-methoxyethyl acrylate, 3-methoxybutyl acrylate, trimethoxysilylpropyl acrylate, triacrylate Fluoroethyl, isopropyl acrylate, sec-butyl acrylate, t-butyl acrylate, cyclohexyl acrylate, isobornyl acrylate, trimethylsilyl acrylate, and the like, and the acrylate is not limited to one type It can be used two or more kinds. In the polymerization reaction according to the present invention, since the effect is particularly remarkably exerted in the polymerization of primary alkyl acrylate, it is preferable that the acrylic ester used is mainly primary alkyl acrylate.

In addition, as long as the desired polymerization is not adversely affected, other anionic polymerizable monomers can be used together with the acrylate ester as a small component, if necessary, for copolymerization. Representative examples of copolymerizable anionic polymerizable monomers include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, and 2-ethyl methacrylate. Kishiru,
Lauryl methacrylate, cesyl methacrylate, n-stearyl methacrylate, glycidyl methacrylate, allyl methacrylate, 2-methoxyethyl methacrylate, 3-methoxybutyl methacrylate, trimethoxysilylpropyl methacrylate, trifluoroethyl methacrylate,
Methacrylic esters such as trimethylsilyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, and isobornyl methacrylate; N-isopropylacrylamide, Nt-butylacrylamide, N, N
Acrylamide compounds such as -dimethylacrylamide, N, N-diethylacrylamide; N-isopropylmethacrylamide, Nt-butylmethacrylamide,
And methacrylamide-based compounds such as N, N-dimethylmethacrylamide and N, N-diethylmethacrylamide.

It is preferable that the monomer such as an acrylate ester used in the present invention is sufficiently dried in advance under an inert gas stream or the like from the viewpoint of facilitating the polymerization reaction. Dehydrating and drying agents such as calcium hydride, molecular sieves and activated alumina are preferably used.

The polymerization reaction of the acrylate according to the present invention can be carried out without using an organic solvent.
It is preferable to carry out the reaction in an organic solvent, since the polymerization temperature can be controlled, the conditions in the polymerization system can be made uniform, and the polymerization can proceed smoothly. At that time, a hydrocarbon solvent and / or a halogenated hydrocarbon solvent are preferred from the viewpoints of relatively high safety when handling chemicals, hardly mixing into wastewater, and easy recovery and purification of the solvent. Used.
Representative examples of usable hydrocarbon solvents include benzene,
Examples thereof include toluene, xylene, cyclohexane, and methylcyclohexane, and usable halogenated hydrocarbon solvents include chloroform, methylene chloride, and carbon tetrachloride. These organic solvents may be used alone or in combination of two or more. Among them, hydrocarbon solvents are more preferably used.

It is preferable that the organic solvent used for the polymerization is purified by deaeration and dehydration beforehand.

The amount of the organic solvent used depends on the desired degree of polymerization of the acrylate polymer, the type of the acrylate ester, the type of the organic lithium compound, the type of the organic aluminum compound (I), the type of the organic solvent, and the like. However, in general, an organic solvent is used for the acrylate ester 100 to be used in view of smooth progress of polymerization, easy separation and acquisition of the produced acrylate polymer, burden on waste liquid treatment, and the like. It is preferably used in a proportion within the range of 200 to 3000 parts by weight with respect to parts by weight, and 300 to 200 parts by weight.
It is more preferable to use it in a proportion that falls within the range of 0 parts by weight.

The method of adding the organolithium compound, the organoaluminum compound (I) and the acrylate to the polymerization system is not particularly limited, and any suitable method can be employed as desired. For example, as for the organolithium compound and the organoaluminum compound (I), each may be added to the polymerization system as it is, or one or both may be added to the polymerization system in a state of being dissolved in an organic solvent or an acrylate ester. May be. The acrylic acid ester may be supplied as it is to the polymerization system, or may be supplied to the polymerization system in a state of being dissolved in an organic solvent in advance.

If the polymerization reaction is carried out on an industrial scale,
From the viewpoint of facilitating the temperature control of the polymerization system, it is sometimes preferable to carry out the polymerization reaction while supplying the acrylate itself or a solution containing the same to the polymerization reaction system. In this case, the supply of the acrylate ester may be continuous or intermittent.

An organolithium compound at the start of polymerization,
Regarding the contact sequence of the organoaluminum compound (I) and the acrylate, generally, the polymerization is initiated by contacting the organolithium compound with the organoaluminum compound (I) and then with the acrylate, Alternatively, the polymerization is preferably initiated by bringing the organolithium compound into contact with a part of the organoaluminum compound (I) and then contacting the mixture with the acrylate and the remainder of the organoaluminum compound (I). When these orders are employed, the deactivated component in the acrylate ester can be inactivated by the action of the organoaluminum compound (I).
By forming a complex between the acrylate and the organoaluminum compound (I), it becomes possible to further improve the living property in polymerization.

In the polymerization reaction according to the present invention, if necessary, other additives can be added to the polymerization system according to known techniques. For example, inorganic salts such as lithium chloride; alkoxide compounds such as lithium 2- (2-methoxyethoxy) ethoxide and potassium t-butoxide;
Organic quaternary salts such as tetraethylammonium chloride and tetraethylphosphonium bromide are exemplified.

The polymerization reaction according to the present invention is preferably carried out in an atmosphere of an inert gas such as nitrogen, argon, helium and the like. Further, it is preferable to carry out the polymerization under sufficient stirring conditions so that the reaction system becomes uniform.

With respect to the polymerization temperature in the polymerization reaction according to the present invention, suitable conditions are appropriately selected according to the type of the organic lithium compound, the type of the organic aluminum compound (I), the type of the organic solvent, the type of the acrylate, and the like. Can be adopted. Generally, if a low polymerization temperature is employed, disadvantages such as a decrease in polymerization initiation efficiency, a decrease in living polymerization property, and an increase in molecular weight distribution (increase in nonuniformity of molecular weight) can be easily suppressed. Excessive lowering is industrially disadvantageous in terms of increased cooling utility requirements, lower polymerization rates, and the like. In general, the acrylate polymer having a uniform molecular weight (degree of polymerization) can be produced industrially at a high yield in a high yield while maintaining high living polymerizability. The temperature is preferably in the range of −80 ° C. to + 20 ° C.

In the polymerization reaction according to the present invention, if the polymerization temperature employed is low, the stereoregularity of the resulting acrylate polymer tends to be improved, and the production of an acrylate polymer having crystallinity is also possible. It is possible. Acrylic acid ester polymers (especially primary alkyl acrylate polymers) are generally excellent in softness, and by imparting crystallinity to them, excellent softness and excellent heat resistance or chemical resistance are obtained. It is possible to obtain a material that has both properties.

For the purpose of producing an acrylic ester polymer having crystallinity, the polymerization temperature is preferably -40 ° C. or lower. From the viewpoint of crystallinity, the lower limit of the polymerization temperature is not limited, but in consideration of both the anion activity at the end of the growing species and the polymerization rate, the temperature is from -100C to-
Preferably, a temperature in the range of 40 ° C. is used,
More preferably, a temperature in the range of 0 ° C to -50 ° C is employed. When the polymerization reaction according to the present invention is carried out at a temperature of -40C or lower, the resulting crystalline acrylate polymer usually has a syndiotactic triad (rr) of 35% or more. To achieve higher crystallinity, the syndiotacticity of the acrylate polymer is preferably 40% or more in a syndiotactic triad (rr). The syndiotacticity of the acrylate polymer is determined by ¹³ C-NMR measurement of the polymer in the form of a deuterated chloroform solution. The peak at around 64.35 ppm [syndiotactic triad (rr)] And a peak near 64.43 ppm [attributed to heterotactic triad (rm)] and 64.43 ppm.
It is expressed as a ratio of the area of the peak attributed to the syndiotactic triad (rr) to the sum of the areas of the peaks near 56 ppm [attributable to the isotactic triad (mm)]. The confirmation of the crystallinity of the acrylate polymer can be carried out according to a known method such as DSC (differential scanning calorimeter) measurement, X-ray diffraction measurement, optical microscope observation and the like.

Regarding the polymerization time, the type of acrylate, the type of organic solvent, the type of organic lithium compound,
A suitable time may be appropriately selected according to various conditions such as the type of the organoaluminum compound (I), the polymerization temperature, the molecular weight of the target acrylate polymer, and the monomer concentration in the organic solvent. If the polymerization time is too short, the proportion of unreacted monomers increases, and conversely, if the polymerization time is too long, the productivity is reduced.
A polymerization time in the range of 0 hours is preferably employed.

When an acrylic ester polymer is produced on an industrial scale, it is difficult to strictly prevent the deactivation of a part of the polymerization initiator, and therefore, it is difficult to prevent the deactivation of the polymerization initiator based on the intended molecular weight. Even if the polymerization reaction according to the present invention is carried out using a theoretically calculated ratio of a polymerization initiator and an acrylic ester, an acrylic ester polymer having a desired molecular weight may not be obtained. For the purpose of producing an acrylic ester polymer having a predetermined average molecular weight with particularly high reproducibility on an industrial scale, it is preferable to carry out the polymerization operation in two stages by the following method. That is, polymerization is carried out using a monomer (such as an acrylate ester) in a smaller amount than the theoretically calculated required amount based on the amount of the polymerization initiator (organic lithium compound) used to form a living polymer in the reaction system. The molecular weight of the living polymer is measured, the number of moles of the living polymer is calculated based on the molecular weight and the amount of the monomer used, and the molecular weight and the number of moles of the living polymer and the molecular weight of the desired final polymer are formed. The amount of the monomer to be added is calculated based on the above, and by polymerizing the amount of the monomer to be added to the living polymer, an acrylic ester polymer having a target molecular weight is highly reproducible. It is possible to manufacture with.

In the present invention, the polymerization reaction can be stopped by adding a polymerization terminator to the reaction mixture at the stage when the desired acrylate polymer is formed by the polymerization reaction. As the polymerization terminator, for example, a protic compound such as a methanol solution of methanol, acetic acid, or hydrochloric acid can be used. Although the amount of the polymerization terminator used is not particularly limited, it is generally preferable to use the polymerization terminator in a ratio of 1 to 100 mol per 1 mol of the organolithium compound used as the polymerization initiator.

In the present invention, after the polymerization of all the predetermined acrylates has been completed and before the addition of the polymerization terminator, a polyfunctional acrylate or methacrylic ester having two or more functional groups is used. By adding an acid ester to the reaction system, a so-called "star type" or "multi-arm type" acrylate polymer can be produced. Further, in the present invention, after all the polymerization of the predetermined acrylic acid ester is completed and before the addition of the polymerization terminator, a terminal functional group-providing agent (for example, aldehyde, lactone, carbon dioxide or the like) or a small amount is added. A functional group-containing anionic polymerizable monomer (e.g., glycidyl methacrylate) may be added to the reaction system. In such a case, an acryl having a functional group such as a hydroxyl group, a carboxyl group, or an epoxy group at a molecular chain terminal. An acid ester polymer can be obtained. That is, when polymerization is performed using a monofunctional anionic polymerization initiator, an acrylate polymer having a functional group at one end of a molecular chain can be obtained, and a bifunctional anionic polymerization initiator is used. When polymerization is carried out by the above method, an acrylate polymer having functional groups at both ends of the molecular chain can be obtained.

If the metal component derived from the organolithium compound or the organoaluminum compound (I) remains in the acrylate polymer separated and obtained from the reaction mixture after the termination of the polymerization, the acrylate polymer or the acrylate polymer is removed. The purpose of using the acrylic ester polymer is that the physical properties (adhesive strength, adhesive strength, etc.) of the materials used (for example, adhesives, adhesives, etc.) may decrease and the transparency may be poor (defective appearance, coloring, etc.). In some cases, it is preferable to remove the metal compound derived from the organolithium compound and the organoaluminum compound (I) after completion of the polymerization. As a method for removing the metal compound, it is effective to subject the acrylic ester polymer to a cleaning treatment such as a washing treatment using an acidic aqueous solution or an adsorption treatment using an adsorbent such as an ion exchange resin. The organoaluminum compound (I) reacts with moisture in the air even after the polymerization is stopped, and is easily converted to aluminum hydroxide.
Since aluminum hydroxide is hardly soluble in both acidic aqueous solution and alkaline aqueous solution, once formed, it becomes difficult to remove it.
Therefore, it is preferable to wash the acrylic acid ester polymer (which may be in the form of a reaction mixture) as soon as possible after the polymerization using an acidic aqueous solution in terms of the efficiency of removing metal components. As the acidic aqueous solution, for example, hydrochloric acid, sulfuric acid aqueous solution, nitric acid aqueous solution, acetic acid aqueous solution, propionic acid aqueous solution, citric acid aqueous solution and the like can be used.

The method for separating and obtaining the acrylate polymer from the reaction mixture after the termination of the polymerization is not particularly limited, and any method according to a known method can be adopted. For example, a method in which the reaction mixture is poured into a poor solvent for the acrylate polymer to precipitate the acrylate polymer, a method in which the solvent is distilled off from the reaction mixture to obtain the acrylate polymer, and the like can be adopted. is there.

Further, according to the method of the present invention, an acrylate polymer having an arbitrary molecular weight can be produced. Although the molecular weight of the acrylate polymer that can be produced is wide-ranging, generally, the number average molecular weight is 1000 to 1000.
Within the range of 1,000,000, the handleability, fluidity, and other polymers of the acrylate polymer (eg, acrylic resin, vinyl chloride resin, fluorine resin, etc.)
It is preferable from the viewpoints of compatibility, paintability, adhesiveness, tackiness and the like. In addition, according to the method of the present invention, an acrylate polymer having high molecular weight uniformity (that is, narrow molecular weight distribution) is usually obtained, and its molecular weight distribution (Mw / Mn) is obtained.
Is often 1.5 or less.

The acrylic ester polymer obtained by the method of the present invention can be used for adhesives, pressure-sensitive adhesives, paints, foams, etc. by utilizing its excellent transparency, chemical resistance, weather resistance, flexibility, handleability and the like. It is useful as a raw material of a body, a cushioning material, a vibration damping material, a vibration damping material, a sealing material, a sealing material, an additive, and the like. Further, by adding the acrylate polymer obtained by the method of the present invention to other thermoplastic resins, thermosetting resins, and the like used for various molded articles in the electric / electronic field, the automobile field, the medical field, and the like. It is also possible to improve the impact resistance, paintability, printability, weather resistance and the like. Moreover,
Use as a compatibilizer between a plurality of resins is also possible. The acrylate ester polymer obtained by the method of the present invention can exhibit excellent mechanical properties when formed into a molded product, due to the uniformity of the molecular weight distribution, and when added to another thermoplastic resin. Excellent moldability can be demonstrated. When the acrylate polymer obtained by the method of the present invention has a functional group at one end or both ends of its main chain, the polymer is used as a raw material component of a polymer such as polyester, polyurethane, polyamide, and polyimide. You can also. When the acrylate polymer obtained by the method of the present invention has a polymerizable vinyl group at one end or both ends of its main chain, the polymer can be used as a macromonomer or a crosslinking agent. .

When the acrylate polymer obtained by the method of the present invention is used for various purposes, the acrylate polymer is added to a deterioration inhibitor such as an antioxidant and an ultraviolet absorber, a plasticizer, An agent, a thickener, a resin or oligomer such as a tackifier resin, a colorant, a pigment, a bulking agent, and the like may be added.

[0063]

Next, the present invention will be specifically described with reference to examples and the like, but the present invention is not limited to the following examples.

Reference Example 1 [Organic aluminum compound (I): isobutyl bis (2,6-di-t-butyl-4)
Preparation of -Methylphenoxy) aluminum] After drying with sodium, 34 ml of dry toluene obtained by distillation under a nitrogen atmosphere, and 11.02 g of 2,6-di-t-butyl-4-methylphenol were mixed with nitrogen in an internal atmosphere. It was added to the replaced flask having an inner volume of 200 ml and dissolved at room temperature with stirring. 6.31 ml of triisobutylaluminum was added to the resulting solution, and the mixture was stirred at 80 ° C. for about 18 hours to give the corresponding organoaluminum compound (I) [isobutylbis (2,6-di-t-butyl-
0.5 mol of 4-methylphenoxy) aluminum]
/ L of a toluene solution was prepared.

Reference Example 2 [Organic aluminum compound (I): n-octylbis (2,6-di-t-butyl-
Preparation of 4-methylphenoxy) aluminum] After drying with sodium, 31 ml of dry toluene obtained by distillation under an argon atmosphere, and 2,6-di-t-butyl-4-
11.02 g of methylphenol was added to a 200-ml flask whose internal atmosphere was replaced with argon,
Dissolve with stirring at room temperature. Tri-n-
9.17 g of octylaluminum is added and stirred at 80 ° C. for about 18 hours to give the corresponding organoaluminum compound (I) [n-octylbis (2,6-di-t
-Butyl-4-methylphenoxy) aluminum] at a concentration of 0.5 mol / l.

Reference Example 3 [Organic aluminum compound:
Preparation of ethyl bis (2,6-di-t-butyl-4-methylphenoxy) aluminum] 36 ml of dry toluene obtained by drying with sodium and then distillation under an argon atmosphere, and 2,6-di-t-butyl-4 −
11.02 g of methylphenol was added to a 200-ml flask whose internal atmosphere was replaced with argon,
Dissolve with stirring at room temperature. To the resulting solution was added 3.42 ml of triethylaluminum, and the mixture was added at 80 ° C for about 18 hours.
By stirring for a period of time, a toluene solution containing the corresponding organoaluminum compound [ethyl bis (2,6-di-t-butyl-4-methylphenoxy) aluminum] at a concentration of 0.5 mol / l was prepared.

Reference Example 4 [Organic aluminum compound:
Preparation of diisobutyl (2,6-di-t-butyl-4-methylphenoxy) aluminum] 39 ml of dry toluene obtained by drying with sodium and then distilling under a nitrogen atmosphere, and 2,6-di-t-butyl-4 5.51 g of methylphenol was added to a 200-ml flask whose internal atmosphere was replaced with nitrogen, and dissolved at room temperature with stirring. 6.31 ml of triisobutylaluminum was added to the obtained solution, and the mixture was stirred at 80 ° C. for about 18 hours to give a corresponding organic aluminum compound [diisobutyl (2,6-di-t-butyl-4-methylphenoxy) aluminum. ] At a concentration of 0.5 mol / l.

Reference Example 5 [Organic aluminum compound:
Preparation of methyl bis (2,6-di-t-butyl-4-methylphenoxy) aluminum] 37 ml of dry toluene obtained by drying with sodium and then distilling under an argon atmosphere, and 2,6-di-t-butyl-4 −
11.02 g of methylphenol was added to a 200-ml flask whose internal atmosphere was replaced with argon,
Dissolve with stirring at room temperature. 2.40 ml of trimethylaluminum was added to the obtained solution,
By stirring for a time, a toluene solution containing the corresponding organoaluminum compound [methylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum] at a concentration of 0.5 mol / l was prepared.

Example 1 [Isobutylbis (2,6-
Production of crystalline n-butyl polyacrylate using di-t-butyl-4-methylphenoxy) aluminum] After placing 14 ml of dry toluene in a 120 ml inner volume Schlenk tube in which the internal atmosphere has been replaced with argon, -78
° C, and a toluene solution of an organoaluminum compound (I) [isobutylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum] prepared in the same manner as in Reference Example 1 above (concentration: 0.5mol /
3.76 ml of 1) was added. Then, a pentane solution of t-butyllithium (concentration: 1.6 mol / l) was added to 0.12.
Then, 1.9 g of n-butyl acrylate was added, polymerization was carried out for 10 minutes, and then the polymerization was stopped by adding about 0.02 ml of methanol. When a part of the obtained solution was sampled and dissolved in deuterated chloroform and subjected to ¹ H-NMR measurement, there was no peak attributed to the n-butyl acrylate monomer,
It was found that the polymerization rate of n-butyl acrylate was 98% or more. The remaining portion of the obtained solution was poured into methanol, and the precipitated white precipitate was collected, dissolved in tetrahydrofuran, and subjected to GPC (gel permeation chromatography) measurement using the solution. The obtained n-butyl polyacrylate shows a monomodal peak, and its polystyrene reduced number average molecular weight (Mn).
Is 11600, and the molecular weight distribution (Mw / Mn) is 1.
08. Further analysis of the n-butyl polyacrylate by ¹³ C-NMR revealed that the syndiotacticity was 55% by triad (rr).
%Met. In addition, an endothermic peak was observed at 52 ° C. in DSC measurement of this poly (n-butyl acrylate), and spherical crystals were observed in optical microscope observation (the crystals were melted by raising the temperature to about 70 ° C.).
From the above, it was confirmed that the poly (n-butyl acrylate) had crystallinity.

<< Comparative Example 1 >> [Ethylbis (2,6-di-
Production of n-butyl polyacrylate using t-butyl-4-methylphenoxy) aluminum] A toluene solution of an organoaluminum compound was prepared in the same manner as in Reference Example 3 above, and an organoaluminum compound [ethylbis (2 , 6-Di-t-butyl-4-methylphenoxy) aluminum] in toluene (concentration:
A polymerization operation and a polymerization termination operation were performed in the same manner as in Example 1 except that the amount was changed to 0.5 mol / l) (amount used: 3.76 ml). Sampling a part of the obtained solution,
It was dissolved in deuterated chloroform and subjected to ¹ H-NMR measurement. As a result, it was found that the polymerization rate of n-butyl acrylate was only about 4%.

Comparative Example 2 [Ethylbis (2,6-di-
Production of n-butyl polyacrylate using t-butyl-4-methylphenoxy) aluminum] A toluene solution of an organoaluminum compound was prepared in the same manner as in Reference Example 3 above, and an organoaluminum compound [ethylbis (2 , 6-Di-t-butyl-4-methylphenoxy) aluminum] in toluene (concentration:
0.5 mol / l) (amount used: 3.76 ml), and a polymerization operation and a polymerization termination operation were performed in the same manner as in Example 1 except that the polymerization time was changed from 10 minutes to 1 hour. A part of the obtained solution was sampled, dissolved in deuterated chloroform, and subjected to ¹ H-NMR measurement. As a result, the polymerization rate of n-butyl acrylate was about 21%.
Turned out to be.

Comparative Example 3 [Ethylbis (2,6-di-
Production of crystalline n-butyl polyacrylate using t-butyl-4-methylphenoxy) aluminum] An organoaluminum compound [ethyl bis] prepared in the same manner as in Reference Example 3 above using a toluene solution of an organoaluminum compound (2,6-di-t-butyl-4-methylphenoxy) aluminum] in toluene (concentration:
0.5 mol / l) (amount used: 3.76 ml), and the polymerization operation and the polymerization termination operation were performed in the same manner as in Example 1 except that the polymerization time was changed from 10 minutes to 22 hours. A part of the obtained solution was sampled, dissolved in deuterated chloroform, and subjected to ¹ H-NMR measurement. As a result, the polymerization rate of n-butyl acrylate was 98%.
It turned out that it was above. The remaining part of the obtained solution was poured into methanol, and the precipitated white precipitate was collected.
It was dissolved in tetrahydrofuran, and GPC measurement was performed using the solution.
-Butyl exhibited a monomodal peak, and its polystyrene reduced number average molecular weight (Mn) was found to be 11,200, and its molecular weight distribution (Mw / Mn) was found to be 1.26. Further, the n-butyl polyacrylate was obtained by DSC
An endothermic peak was observed at 50 ° C. in the measurement, and a spherical crystal was observed by optical microscope observation (this crystal was about 7
It was melted by raising the temperature to 0 ° C). From the above, it was confirmed that the poly (n-butyl acrylate) had crystallinity.

Comparative Example 4 [Production of n-butyl polyacrylate using diisobutyl (2,6-di-tert-butyl-4-methylphenoxy) aluminum] The temperature was changed from -78 ° C to -30 ° C. And a toluene solution of the organoaluminum compound was prepared in the same manner as in the above Reference Example 4 [diisobutyl (2,6-di-t-butyl-4-methylphenoxy)
Aluminum] toluene solution (concentration: 0.5 mol /
1) A polymerization operation and a polymerization termination operation were carried out in the same manner as in Example 1 except that the amount was changed to (amount used: 3.76 ml) and the polymerization time was changed from 10 minutes to 24 hours. A part of the obtained solution was sampled, dissolved in deuterated chloroform, and subjected to ¹ H-NMR measurement. As a result, n-butyl acrylate hardly polymerized, and the polymerization rate was 3% or less. Turned out to be.

Comparative Example 5 [Methyl bis (2,6-di-
Production of n-butyl polyacrylate using t-butyl-4-methylphenoxy) aluminum] A toluene solution of an organoaluminum compound was prepared in the same manner as in Reference Example 5 above, and an organoaluminum compound [methylbis (2 , 6-Di-t-butyl-4-methylphenoxy) aluminum] in toluene (concentration:
0.5 mol / l) (used amount: 3.76 ml), the temperature during polymerization was changed from -78 ° C to -60 ° C, and the polymerization time was changed from 10 minutes to 24 hours. A polymerization operation and a polymerization termination operation were performed in the same manner as in 1. A part of the obtained solution was sampled, dissolved in deuterated chloroform, and subjected to ¹ H-NMR measurement. As a result, it was found that the polymerization rate of n-butyl acrylate was 68%. The remaining portion of the obtained solution was poured into methanol, and the precipitated white precipitate was collected, dissolved in tetrahydrofuran, and subjected to GPC measurement using the solution. Butyl shows a monomodal peak, its polystyrene reduced number average molecular weight (Mn) is 10500, and its molecular weight distribution (Mw /
Mn) was found to be 1.72.

Example 2 [Isobutylbis (2,6-
Di-t-butyl-4-methylphenoxy) aluminum
Production of amorphous poly (n-butyl acrylate) using Example 1 except that the temperature was changed from −78 ° C. to −30 ° C.
A polymerization operation and a polymerization termination operation were performed in the same manner as described above. Profit
Sample a portion of the solution, and deuterate it.
Dissolved in loroform¹H-NMR measurement
The peak attributed to the n-butyl acrylate monomer
Not present, the polymerization rate of n-butyl acrylate is 98% or more
Turned out to be. Remove the rest of the resulting solution
Pour into ethanol and collect the white precipitate that has precipitated.
Is dissolved in tetrahydrofuran, and the solution is used for GP.
When the C measurement was carried out, the obtained n-butyl polyacrylate was obtained.
Chill shows a unimodal peak and its polystyrene equivalent number
The average molecular weight (Mn) is 17,700, and the molecular weight distribution
(Mw / Mn) was found to be 1.15. Further
This n-butyl polyacrylate ¹³By C-NMR
Analysis shows that the syndiotacticity
Add (rr) was 33%. Also, this polyac
N-Butyl lylate has an endothermic peak in DSC measurement.
Since it was not observed, it was found to be amorphous.
Was.

Example 3 [n-octylbis (2,6
-Di-t-butyl-4-methylphenoxy) aluminium
Of amorphous poly (n-butyl acrylate) using
The temperature is changed from -78 ° C to -30 ° C, and the organic aluminum
The toluene solution of the ammonium compound (I) was used in Reference Example 2 above.
Aluminum compound prepared in the same manner as
(I) [n-octyl (2,6-di-t-butyl-4-
Methylphenoxy) aluminum] in toluene (concentrated
(Degree: 0.5 mol / l) (used amount: 3.76 ml)
A polymerization operation and polymerization were carried out in the same manner as in Example 1 except for the changes.
Stop operation was performed. Part of the obtained solution is sampled
And dissolve it in deuterated chloroform¹H-NM
When the R measurement was performed, the n-butyl acrylate monomer
There are no assigned peaks and n-butyl acrylate
The conversion was found to be 98% or more. The resulting solution
The remaining part of the solution was poured into methanol, and the white precipitate
Collect the residue, dissolve it in tetrahydrofuran,
GPC measurement was performed using the solution of
N-Butyl acrylate exhibits a unimodal peak,
The polystyrene reduced number average molecular weight (Mn) is 21,000
Yes, molecular weight distribution (Mw / Mn) is 1.13
There was found. Further, the n-butyl polyacrylate is
¹³When analyzed by C-NMR, the syndiota
Kuchishichi was 36% in triad (rr).
This poly (n-butyl acrylate) was used for DSC measurement.
No endothermic peak was observed at
Turned out to be.

Example 4 [Isobutylbis (2,6-
Production of 2-ethylhexyl polyacrylate using di-t-butyl-4-methylphenoxy) aluminum (with washing treatment) The temperature was changed from -78 ° C to -30 ° C, and the monomer was changed to acrylic acid. A polymerization operation and a polymerization termination operation were performed in the same manner as in Example 1 except that n-butyl was changed to 2-ethylhexyl acrylate (use amount: 1.9 g) and the polymerization time was changed from 10 minutes to 3 hours. Was. After adding 10 ml of 1N diluted sulfuric acid to the obtained solution and stirring, liquid separation was performed, and an organic layer was recovered. To the collected organic solution, a series of washing operations including addition of water (10 ml), stirring, liquid separation and removal of an aqueous layer was repeated five times. The solution after washing was poured into methanol, and a white precipitate deposited was collected and dried under vacuum to completely remove the solvent. The obtained 2-ethylhexyl polyacrylate is a colorless and transparent liquid substance,
It was substantially free of metal components. Further, the yield based on the recovered amount of 2-ethylhexyl polyacrylate was 97%.
%, It was found that the polymerization proceeded almost quantitatively. The 2-ethylhexyl polyacrylate was dissolved in tetrahydrofuran, and the solution was subjected to a GPC measurement to show a monomodal peak. The polystyrene-equivalent number average molecular weight (Mn) was 11,600, and the molecular weight distribution ( M
(w / Mn) was found to be 1.14.

The results obtained for Examples 1 to 4 and Comparative Examples 1 to 5 are shown in Table 1 below together with main polymerization conditions.

[0079]

[Table 1]

The symbols in Table 1 have the following meanings. iBAl (BHT) 2: isobutylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum nOAl (BHT) 2: n-octylbis (2,6-di-t-butyl-4-methylphenoxy) Aluminum EtAl (BHT) 2: ethyl bis (2,6-di-t-butyl-4)
-Methylphenoxy) aluminum MeAl (BHT) 2: methylbis (2,6-di-t-butyl-4)
-Methylphenoxy) aluminum iB2Al (BHT): diisobutyl (2,6-di-t-butyl-
4-methylphenoxy) aluminum t-BuLi: t-butyllithium nBA: n-butyl acrylate 2-EHA: 2-ethylhexyl acrylate

From Table 1 above, it can be seen that Examples 1 to 5 according to the present invention were used.
In the production example of the acrylate polymer of No. 4, it can be understood that a polymer having a uniform molecular weight distribution can be produced at a high polymerization rate while having a relatively short polymerization time. In addition, when a relatively low polymerization temperature is employed (Example 1), it is also understood that an acrylic acid ester polymer having crystallinity can be produced. On the other hand, in the production examples of the acrylate polymer of Comparative Examples 1 to 5, which are different from the present invention in the chemical structure of the organoaluminum compound used, a long polymerization time is required to achieve a high polymerization rate. I understand. Further, it can be seen that the uniformity of the molecular weight distribution of the obtained acrylate polymer tends to be slightly inferior to that of the present invention (Comparative Examples 3 and 5).

Example 5 [Isobutyl bis (2,6-
N-Polyacrylate by two-stage polymerization using di-tert-butyl-4-methylphenoxy) aluminum
Production of butyl] (1) Internal volume 120 m with the internal atmosphere replaced with argon
After putting 64 ml of dry toluene into a Schlenk tube of 1 l,
After cooling to −30 ° C., the organoaluminum compound (I) [isobutylbis (2,6-di-t-butyl-4-methylphenoxy) prepared in the same manner as in Reference Example 1 above.
Aluminum] toluene solution (concentration: 0.5 mol /
3.76 ml of 1) was added. Then, a pentane solution of t-butyllithium (concentration: 1.6 mol / l) was added to 0.12.
Then, 1.9 g of n-butyl acrylate was added and polymerization was carried out for 10 minutes. A portion of the resulting solution was sampled and dissolved in deuterated chloroform for ¹
When H-NMR measurement was performed, no peak attributed to the n-butyl acrylate monomer was present, and
It was found that the conversion of butyl was 98% or more. Further, the collected sample was poured into methanol, and the precipitated white precipitate was collected, dissolved in tetrahydrofuran, and subjected to GPC measurement using the solution. The resulting n-butyl polyacrylate was monomodal. And a polystyrene reduced number average molecular weight (Mn) of 18
800 and the molecular weight distribution (Mw / Mn) was found to be 1.16.

(2) The remaining part of the obtained solution was -30
C. for 1 hour with stirring at room temperature.
5.7 g of butyl was further added, polymerization was carried out at -30 ° C for 3 hours, and the polymerization was stopped by adding about 0.02 ml of methanol. A part of the obtained solution was sampled and dissolved in deuterated chloroform to give ¹ H-NM.
R measurement revealed that the polymerization rate of the added n-butyl acrylate was about 45%. The remaining portion of the resulting solution was poured into methanol, and the precipitated white precipitate was collected, dissolved in tetrahydrofuran, and subjected to GPC measurement using the solution. The n-butyl acid shows a single peak with a slight shoulder on the low molecular weight side, its polystyrene equivalent number average molecular weight (Mn) is 27,800, and its molecular weight distribution (Mw / Mn) is 1.60. There was found. The obtained GPC chart is shown in FIG.

<< Comparative Example 6 >> [Ethylbis (2,6-di-
Production of n-butyl polyacrylate by two-stage polymerization using t-butyl-4-methylphenoxy) aluminum] (1) A toluene solution of an organoaluminum compound was prepared in the same manner as in Reference Example 3 above. Example 1 was changed to a toluene solution (concentration: 0.5 mol / l) (used amount: 3.76 ml) of an organoaluminum compound [ethylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum]. The first-stage polymerization operation was performed in the same manner as in (1) of No. 5. A part of the obtained solution was sampled and dissolved in deuterated chloroform to give ¹ H-NM.
R measurement revealed that there was no peak attributed to the n-butyl acrylate monomer, indicating that the polymerization rate of n-butyl acrylate was 98% or more. Further, the collected sample was poured into methanol, and the precipitated white precipitate was collected, dissolved in tetrahydrofuran, and subjected to GPC measurement using the solution. The resulting poly (n-butyl acrylate) had a low molecular weight. A peak with a shoulder on the side, and its polystyrene reduced number average molecular weight (Mn)
Is 19000, and the molecular weight distribution (Mw / Mn) is 1.
It turned out to be 35.

(2) The remaining part of the obtained solution was -30
C. for 1 hour with stirring at room temperature.
Further 5.7 g of butyl was added, polymerization was carried out at -30 ° C for 3 hours, and the polymerization was stopped by adding about 0.02 ml of methanol. A part of the obtained solution was sampled and dissolved in deuterated chloroform to obtain ¹ H-N
MR measurement revealed that the polymerization rate of the added n-butyl acrylate was about 42%. The remaining portion of the resulting solution was poured into methanol, and the precipitated white precipitate was collected and dissolved in tetrahydrofuran.
When GPC measurement was performed using the solution, the finally obtained n-butyl polyacrylate showed a bimodal peak, and its polystyrene reduced number average molecular weight (Mn) was 2
7,300 and a molecular weight distribution (Mw / Mn) of 1.96.
Therefore, it was found that a polymer whose molecular weight distribution was controlled uniformly could not be obtained. FIG. 2 shows the obtained GPC chart. Since there is a peak corresponding to n-butyl polyacrylate obtained in the first-stage polymerization operation in the above (1) on the low molecular weight side, the living polymer (polyacrylic) formed in the first-stage polymerization operation is present. Acid n
It can be seen that the deactivation in the period up to the start of the second polymerization operation in (-butyl) is not negligible.

The production example of the acrylate polymer of Example 5 according to the present invention and the production example of the acrylate polymer of Comparative Example 6, which differ from the present invention in the chemical structure of the organoaluminum compound used, By contrast, it can be seen that the polymerization reaction according to the present invention has a high living property (that is, the life of the anion active terminal of the living polymer in the reaction system is long) and is suitable for a two-stage polymerization technique.

Example 6 [Isobutylbis (2,6-
Production of n-butyl polyacrylate by continuous monomer feed polymerization using di-t-butyl-4-methylphenoxy) aluminum] An autoclave having an inner volume of 10 liters and the inside atmosphere of which is replaced with argon is dried in an autoclave. Put 3.5 liters,
Next, the organoaluminum compound (I) [isobutylbis (2,6) prepared in the same manner as in Reference Example 1 above was used.
-Di-t-butyl-4-methylphenoxy) aluminum] in toluene (concentration: 0.5 mol / l).
0 ml was added. The solution was cooled to −30 ° C. by a cooling bath having a temperature of −35 ° C., and a pentane solution of t-butyllithium (concentration: 1.6 mol / l) was added thereto.
5 ml was added and the mixture was stirred for 20 minutes. While stirring the solution thus prepared, 300 g of n-butyl acrylate was added thereto at a rate of 10 ml / min (time required for addition: 33 minutes), and thereafter, stirring was further continued for 10 minutes to polymerize. The reaction was performed. Immediately after the start of the addition of n-butyl acrylate, the internal temperature began to rise, and rose to a maximum of −24 ° C. during the polymerization reaction. Then, the polymerization was stopped by adding 30 ml of methanol to the polymerization reaction system. Sampling a part of the obtained solution,
When it was dissolved in deuterated chloroform and subjected to ¹ H-NMR measurement, there was no peak attributed to the n-butyl acrylate monomer, and the polymerization rate of n-butyl acrylate was 98% or more. Turned out to be. Further, the collected sample was poured into methanol, and the precipitated white precipitate was recovered, dissolved in tetrahydrofuran, and subjected to GPC measurement using the solution. A peak with a peak, and its polystyrene reduced number average molecular weight (Mn) is 49400;
The molecular weight distribution (Mw / Mn) was found to be 1.05. The GPC chart obtained is shown in FIG. The GPC
Based on the chart, it was found that low molecular weight components having a molecular weight of 10,000 or less were not contained.

Comparative Example 7 [Ethylbis (2,6-di-
Production of n-butyl polyacrylate by continuous monomer feed polymerization using t-butyl-4-methylphenoxy) aluminum] A toluene solution of an organoaluminum compound is prepared in the same manner as in Reference Example 3 above. Solution of the obtained organoaluminum compound [ethyl bis (2,6-di-t-butyl-4-methylphenoxy) aluminum] (concentration:
A polymerization operation and a polymerization termination operation were performed in the same manner as in Example 6 except that the amount was changed to 0.5 mol / l) (amount used: 230 ml). Note that the internal temperature started to rise immediately after the start of the addition of n-butyl acrylate, and a maximum of -2 during the polymerization reaction period.
The temperature rose to 7 ° C. A part of the obtained solution was sampled and dissolved in deuterated chloroform to obtain ¹ H-
As a result of NMR measurement, no peak attributed to the n-butyl acrylate monomer was present, and it was found that the polymerization rate of n-butyl acrylate was 98% or more. Also,
The collected sample was poured into methanol, and the precipitated white precipitate was collected and dissolved in tetrahydrofuran.
When GPC measurement was performed using the solution, the obtained n-butyl polyacrylate showed a monomodal but broad peak, and its polystyrene-equivalent number average molecular weight (M
n) is 53600, and the molecular weight distribution (Mw / Mn) is 2.7.
It turned out to be 1. FIG. 4 shows the obtained GPC chart. Based on the GPC chart, a molecular weight of 100
It was found that about 3% of low molecular weight components of 00 or less were contained.

The production example of the acrylate polymer of Example 6 according to the present invention and the production example of the acrylate polymer of Comparative Example 7 which differ from the present invention in the chemical structure of the organoaluminum compound used By contrast, it can be seen that the polymerization reaction according to the present invention has a high living property (that is, the life of the anion active terminal of the living polymer in the reaction system is long) and is suitable for a monomer continuous feed polymerization method. .

Example 7 [Isobutylbis (2,6-
Production of poly (n-butyl acrylate) using di-tert-butyl-4-methylphenoxy) aluminum] In a 100-ml volumetric flask in which the internal atmosphere was replaced with nitrogen, in the same manner as in Reference Example 1, The prepared organoaluminum compound (I) [isobutylbis (2,6-di-t-butyl-4-methylphenoxy) aluminum]
Of 18.5 in toluene solution (concentration: 0.5 mol / l)
After cooling to −5 ° C., 0.58 ml of a pentane solution of t-butyllithium (1.6 mol / l) was added and stirred for 1 hour to prepare an initiator solution. 28 ml of dry toluene was placed in an ampoule tube having a volume of 100 ml in which the internal atmosphere was replaced with nitrogen, and after cooling to −78 ° C., 12.7 ml of the above initiator system solution was added.
6.9 ml of butyl was added to initiate the polymerization. With the addition of n-butyl acrylate, the polymerization solution became a yellow transparent solution, and after 17 hours, the polymerization was stopped by adding methanol. A part of the obtained colorless and transparent solution was sampled, dissolved in deuterated chloroform, and subjected to ¹ H-NMR measurement. As a result, a peak attributed to the n-butyl acrylate monomer was not present. It was found that the polymerization rate of n-butyl acrylate was 98% or more. This sample was poured into a large amount of methanol, and the deposited precipitate (n-butyl polyacrylate) was recovered. The recovered n-butyl methacrylate was dissolved in tetrahydrofuran and GPC measurement was performed using the solution. The number average molecular weight (Mn) was 39000, and the molecular weight distribution (Mw / Mn) was 1.05. It turned out to be.

Example 8 [Isobutylbis (2,6-
Production of n-butyl polyacrylate using di-t-butyl-4-methylphenoxy) aluminum (with washing treatment)] Place 16 ml of dry toluene in a 100 ml Schlenk tube whose internal atmosphere is replaced with nitrogen. After cooling to −78 ° C., the organoaluminum compound (I) [isobutylbis (2,6-di-t) was prepared in the same manner as in Reference Example 1 above.
-Butyl-4-methylphenoxy) aluminum] in 1.33 ml of toluene solution (concentration: 0.5 mol / l)
added. 0.04 ml of a pentane solution of t-butyllithium (1.6 mol / l) was added thereto, followed by stirring, and 1.12 ml of n-butyl acrylate was added to initiate polymerization. With the addition of n-butyl acrylate, the polymerization solution became a yellow transparent solution, and after 14 hours, the polymerization was stopped by adding methanol. A part of the obtained solution was sampled, dissolved in deuterated chloroform, and subjected to ¹ H-NMR measurement.
There was no peak attributed to -butyl monomer, indicating that the polymerization rate of n-butyl acrylate was 98% or more. The remaining portion of the solution after the termination of the polymerization was washed five times with 50 ml of an aqueous solution containing citric acid at a concentration of 20% by weight, and then washed three times with 50 ml of distilled water. Then, metal components (residues of the organic lithium compound and residues of the organic aluminum compound) were removed. Pour the remaining organic phase into a large amount of methanol,
The deposited precipitate was recovered. The recovered precipitate was n-butyl polyacrylate substantially containing no metal component. It was dissolved in tetrahydrofuran, and the resulting solution was subjected to GPC measurement to find that the number average molecular weight (Mn)
Is 38,000, and the molecular weight distribution (Mw / Mn) is 1.
07.

[0092]

According to the present invention, an acrylic acid ester such as a primary alkyl acrylate is anionically polymerized to achieve both a high polymerization rate and a high living property even when a solvent having a problem in handling properties is not used. Since the polymerization can be carried out while the reaction is being carried out, an acrylate polymer having a desired molecular weight and a narrow molecular weight distribution can be produced with good reproducibility, smoothly and industrially advantageously.

[Brief description of the drawings]

FIG. 1 is a GPC chart of poly (n-butyl acrylate) finally obtained in Example 5 according to the present invention (horizontal axis represents outflow time).

FIG. 2 is a GPC chart of poly (n-butyl acrylate) finally obtained in Comparative Example 6 other than the present invention (the horizontal axis represents outflow time).

FIG. 3 is a GPC chart of n-butyl polyacrylate finally obtained in Example 6 according to the present invention (horizontal axis represents outflow time).

FIG. 4 is a GPC chart of poly (n-butyl acrylate) finally obtained in Comparative Example 7 other than the present invention (the horizontal axis represents outflow time).

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tomohiro Ono 41 Miyukigaoka, Tsukuba, Ibaraki Pref., Kuraray Co., Ltd. Inventor Kazunari Ishiura 41 Miyukigaoka, Tsukuba City, Ibaraki Prefecture Kuraray Co., Ltd.

Claims (8)

[Claims] The method according to claim 1 acrylic acid ester, an organic lithium compound and the following general formula (I); embedded image ^{AlR 1 R 2 R 3 (I} ) ( In the formula, R ¹ may have a substituent An alkyl group having 3 or more carbon atoms, an alkoxy group having 3 or more carbon atoms which may have a substituent or an aryloxy group which may have a substituent, wherein R ² and R ³ each independently represent a substituent; Or an arylenedioxy group in which R ² and R ³ may be bonded to each other, or an arylenedioxy group which may have a substituent.) A method for producing an acrylate polymer. 2. The method according to claim 1, wherein R ¹ in the general formula (I) representing the organoaluminum compound is a branched alkyl group having 3 to 12 carbon atoms. 3. The method according to claim 1, wherein R ¹ in the general formula (I) representing the organoaluminum compound is a linear alkyl group having 4 to 12 carbon atoms. 4. The method according to claim 1, wherein the acrylate is a primary alkyl acrylate. 5. The polymerization is initiated by contacting the organolithium compound with an organoaluminum compound and then with an acrylate, or contacting the organolithium compound with a portion of the organoaluminum compound and The production method according to any one of claims 1 to 4, wherein the polymerization is started by bringing the mixture into contact with a mixture consisting of an acid ester and the remainder of the organoaluminum compound. 6. The production method according to claim 1, wherein the polymerization reaction is carried out while supplying the acrylic acid ester to the polymerization reaction system. 7. The polymerization is carried out using less than the stoichiometric amount of acrylate to form a living polymer, which should be added based on the molecular weight and moles of the living polymer and the molecular weight of the desired final polymer. The method according to any one of claims 1 to 6, wherein the amount of the acrylate is calculated, and then the additional amount of the acrylate is polymerized to the living polymer. 8. The method according to claim 1, wherein after the polymerization is completed, the obtained acrylate polymer is washed with an acidic aqueous solution to remove metal components contained in the acrylate polymer. The production method described in Crab.