JPH10273505A - Production of poly(meth)acrylic ester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to control the stereoregularity of poly(meth)acrylic ester by using as the polymerization initiator a component consisting of at least one metal compound and at least one organoaluminum compound. SOLUTION: A metal compound represented by the formula (wherein A is an aromatic hydrocarbon residue, halogeno, etc.; X is O, NR or S; R is H, a 1-20C hydrocarbon group, etc.; D is a solvent molecule; 0<=a<=4; 0<=b<=6; 2<=a+c<=4; and M is a group IIIb or IVb transition element), an organoaluminum compound, and (meth)acrylic ester at a molar ratio of 1:(0.1-100):(100 to 10,000) are charged into a reactor for polymerization. When an Sm metal compound having two 2,6-di-t-butyl-4-methylphenoxy groups as the ligands and an organoaluminum compound are used at molar ratios of respectively (0.1 to 3):1, 4:1, and (at least 4.5):1, the syndiotacticities of the obtained poly(meth)acrylic esters will be 70-90%, 45%, and 50-70%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a poly (meth) acrylate using a polymerization initiator comprising a specific metal compound and an organoaluminum compound.

[0002]

2. Description of the Related Art Conventionally, poly (meth)
As a method for producing an acrylate ester, a method for producing a vinyl polymer using a divalent rare earth metal compound (Japanese Unexamined Patent Application Publication No.
Japanese Unexamined Patent Publication (Kokai) No. 3-258808) and a method for producing a poly (meth) acrylate using a trivalent rare earth metal compound (Japanese Unexamined Patent Publication No. 3-263412) are known. In these methods, the ligand of the rare earth metal compound used as the polymerization initiator is a π ligand such as a cyclopentadienyl group substituted with an alkyl group or an alkylsilyl group. By using these rare earth metal compounds as a polymerization initiator, a high molecular weight syndiotactic polymethacrylate having a narrow molecular weight distribution can be obtained.

[0003]

However, the polymerization of a (meth) acrylic acid ester with an organic rare earth metal compound having the above-mentioned alkyl group-substituted or alkylsilyl group-substituted cyclopentadienyl group as a ligand gives a polymethacryl There is a problem that the stereoregularity of the acid ester cannot be controlled arbitrarily, and the advent of a polymerization initiator system capable of controlling the stereoregularity of the polymethacrylic acid ester is desired.

The present inventors have conducted intensive studies to solve the above-mentioned problems of the prior art, and as a result, have found that a polymerization initiator comprising at least one specific metal compound and at least one organoaluminum compound is present. In the following, a polymerization system capable of arbitrarily controlling the stereoregularity of polymethacrylic acid ester was found, and the present invention was achieved.

[0005]

According to the present invention, there is provided the following formula (I):
At least one metal compound represented by

[0006]

Embedded image

(In the formula, A-X and Y represent a monovalent ligand, A represents an aromatic hydrocarbon residue, or a halogen, a silicon-containing group, a nitrogen-containing group, a sulfur-containing group, or a phosphorus-containing group. It is a hydrocarbon residue having 1 to 20 carbon atoms, which may have a substituent selected from the group consisting of a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group and an aryloxy group. Two or more A may be mutually bonded via a hydrocarbon group, a silicon-containing group, an O, N, S atom,
It may be bonded without a group. X is an O, NR, or S atom, and R is a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. Y is a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a halogen atom. D is a solvent molecule. a,
b and c are respectively 0 ≦ a ≦ 4, 0 ≦ b ≦ 6, 2 ≦ a + c
≦ 4. M represents a group IIIb or group IVb transition element of the periodic table. ) And at least one organoaluminum compound are used as a polymerization initiator in the method for producing a poly (meth) acrylic acid ester.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is characterized by polymerizing a (meth) acrylic acid ester using at least one metal compound represented by the above formula (I) and at least one organoaluminum compound as a polymerization initiator. I am trying. Examples of the metal atom M used in the above formula (I) include elements of atomic numbers 21 to 71 of Group IIIb of the Periodic Table, that is, S
c, Y, La, Ce, Pr, Nd, Pm, Sm, Eu,
Ga, Tb, Dy, Ho, Er, Tm, Yb or L
u, and Group IVb Ti, Zr, and Hf.
Among these elements, preferred are Y, Sm and Yb, and more preferred is Sm.

Examples of the solvent molecule of D in the above formula (I) include tetrahydrofuran, pyridine, diethyl ether, hexamethylphosphoramide, dimethoxyethane and the like, and preferred is tetrahydrofuran.

A of the ligand AX used in the metal compound represented by the formula (I) is an aromatic hydrocarbon residue or a halogen, a silicon-containing group, a nitrogen-containing group, a sulfur-containing group, or a phosphorus-containing group. Carbon group 1-2 which may have a group
A hydrocarbon residue having 1 to 20 carbon atoms which may have a substituent selected from the group consisting of a 0 hydrocarbon group, an alkoxy group and an aryloxy group, and two or more A's are hydrocarbon groups. It may be bonded via a group, a silicon-containing group, an O, N, or S atom, or may be bonded without a group. X is an O, NR, or S atom, and R is a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. Preferably, it is an aromatic hydrocarbon residue having 1 to 20 carbon atoms, which may have the above-mentioned substituent.

Ligand A- in the metal compound of formula (I)
The following are examples of specific compounds of X.
Alkylalkoxide groups such as methoxide, ethoxide, isopropoxide, isobutoxide; phenoxide,
2,2'-biphenoxide, 2-methyl-6-t-butylphenoxide, 2,6-di-t-butylphenoxide, 2,6-di-t-butyl-4-methylphenoxide, 2,4,6 -Tris (dimethylaminomethyl) phenoxide, α-naphthoxide, β-naphthoxide, phenylphenoxide, p- (methoxyethyl) phenoxide, 2,2'-methylenebis (4-methyl-6-t-butylphenoxide), 2,2 ′ -Methylenebis (4-ethyl-6-t-butylphenoxide), 2,2′-thiobis (4-methyl-6-t-butylphenoxide),
2,2′-bis (naphthoxide), 2,2′-bis (4
-Methoxy-6-t-butylphenoxide), 2,2 '
-Bis (4,6-di-t-butylphenoxide), 3,
3'-bis (trimethylsilyl) -1,1'-bis-
Aryl oxide groups such as 2,2'-naphthoxide; diethylamide, diisobutylamide, di-2-ethylhexylamide, bis (trimethylsilyl) amide, N,
Amide groups such as N-diphenylamide, diallylamide, diisopropylamide; methyl thiolate, ethyl thiolate, isopropyl thiolate, n-butyl thiolate, t-butyl thiolate, n-octyl thiolate, n-dodecyl thiolate, t-dodecyl thiolate, phenyl thiolate, t-amyl thiolate, n-
Hexyl thiolate, n-heptyl thiolate, cyclopentyl thiolate, cyclohexyl thiolate, benzyl thiolate, 2-naphthalene thiolate, o-toluene thiolate, m-toluene thiolate, p-toluene thiolate, 5-t- Thiolate groups such as butyl-2-methylphenylthiolate; acetylacetonate;
Carboxylate, β-aminoketone, β-diketone,
Examples thereof include, but are not limited to, β-ketoimine. Preferred is an aryl oxide group,
More preferably, it is a 2,6-di-t-butyl-4-methylphenoxide group.

The ligand Y in the metal compound represented by the above formula (I) is a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms or a halogen atom. Preferred examples include saturated hydrocarbon groups such as methyl group and butyl group, but the present invention is not limited thereto.

Examples of the organoaluminum compound used in the present invention together with the metal compound represented by the formula (I) include trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, trioctylaluminum, tri-2-ethylhexylaluminum and the like. Trialkylaluminum; dialkylaluminum halides such as dimethylaluminum chloride, diethylaluminum chloride, diisopropylaluminum chloride, diisobutylaluminum chloride and dimethylaluminum bromide; methylaluminum sesquichloride, ethylaluminum sesquichloride, isopropylaluminum sesquichloride, isobutylaluminum sesquichloride,
Alkyl aluminum sesquihalides such as ethyl aluminum sesquibromide; alkyl aluminum dihalides such as methyl aluminum dichloride, ethyl aluminum dichloride, isopropyl aluminum dichloride and ethyl aluminum dibromide; alkyl aluminum hydrides such as diethyl aluminum hydride and diisobutyl aluminum hydride; aluminum triethoxy , Diethyl aluminum monomethoxide, aluminum triisopropoxide, dimethyl aluminum (2,6-di-t-butyl-4-methylphenoxide), methyl aluminum-bis- (2,6
-Di-t-butyl-4-methylphenoxide), aluminum-tris- (2,6-di-t-bryl-4-methylphenoxide) and other alkoxy groups, aryloxy groups, amide group-containing aluminum compounds; methylaluminoxane , Aluminoxanes such as ethylaluminoxane and isobutylaluminoxane are exemplified, but an alkoxy group, a phenoxy group and an amide group-containing aluminum compound are preferable, and methylaluminum-bis- (2,6-di-t- Butyl-4-methylphenoxide).

The (meth) acrylic acid ester used in the present invention is represented by the following formula (II).

CH ₂ ═C (R ¹ ) (CO ₂ R ² ) (II)

(Wherein R ¹ is a hydrogen atom or a methyl group,
R ² represents a monovalent group selected from the group consisting of an aliphatic hydrocarbon group, an aromatic hydrocarbon group, and a hydrocarbon group containing a functional group such as amine and ether. )

Specific examples of the (meth) acrylic acid ester represented by the above formula (II) include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate and methacrylic acid. Isobutyl, sec-butyl methacrylate, tert-butyl methacrylate, isoamyl methacrylate,
N-hexyl methacrylate, cyclohexyl methacrylate, lauryl methacrylate, allyl methacrylate, vinyl methacrylate, benzyl methacrylate, phenyl methacrylate, naphthyl methacrylate, 2-methoxyethyl methacrylate, diethylene glycol monomethyl methacrylate, methacrylic acid 2 -Dimethylaminoethyl, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-acrylate
-Butyl, sec-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, isoamyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, lauryl acrylate, allyl acrylate, vinyl acrylate, dimethylaminoethyl acrylate Examples thereof include, but are not limited to, esters, diethylene glycol ethoxylate acrylate, and the like. Of these, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, methyl acrylate, n-butyl acrylate and isobutyl acrylate are preferable.

The above-mentioned polymerization of the (meth) acrylic ester is carried out by using the metal compound represented by the formula (I) and the organoaluminum compound as a polymerization initiator in an inert gas,
A predetermined amount of the (meth) acrylate and the polymerization initiator are charged into a reaction vessel. The charge ratio (molar ratio) is
With respect to the metal compound 1, the aluminum unit of the organoaluminum compound is in the range of 0.1 to 100 and the (meth) acrylic acid ester of 100 to 10,000. Preferably,
For metal compound 1, the aluminum unit of the organoaluminum compound ranges from 0.1 to 20, and the (meth) acrylate ester ranges from 400 to 5000.

For example, when an Sm metal compound having two molecules of 2,6-di-tert-butyl-4-methylphenoxide as a ligand among the compounds of the formula (I) is used as a polymerization initiator, Poly (meth) acrylate having a syndiotacticity of 70-90% when the molar ratio of the organoaluminum compound to the initiator is about 0.1-3, and 45% each when the molar ratio is about 4
A poly (meth) acrylic acid ester having a degree of syndiotacticity and isotacticity, and a poly (meth) acrylic acid ester having an isotacticity of 50 to 70% when the molar ratio is about 4.5 or more is obtained. be able to.

Examples of the inert gas used in the polymerization of the (meth) acrylic acid ester include nitrogen, helium, argon and the like, preferably argon.

As the (meth) acrylic acid ester monomer, it is preferable to use a monomer which has been sufficiently dried with calcium hydride and molecular sieve and distilled under an inert gas immediately before being subjected to polymerization.

The polymerization is usually carried out in the temperature range of -78 to 200 ° C, preferably -40 to 100 ° C.

The polymerization initiator used in the present invention is:
Usually, the product obtained as a solid is subjected to polymerization. The prepared solution of the polymerization initiator can be used as it is, or the obtained solid can be dissolved in an appropriate solvent and used.

The polymerization does not necessarily require a solvent,
When a solvent is used, hydrocarbons such as benzene, toluene, and xylene, and ethers such as tetrahydrofuran and diethyl ether can be used, but it is preferable to use a completely degassed and dried one. When a solvent is used, the amount used is preferably in the range of 0.5 to 20 parts by weight with respect to 1 part by weight of (meth) acrylic acid ester.

[0024]

The present invention will be described in more detail with reference to the following examples. In the description, the identification of the metal compound and the measurement of the stereoregularity of the polymer were based on ¹ H-NMR.

(Synthesis of Metal Compound) 56 mmol of potassium hydride and 100 ml of tetrahydrofuran were placed in a 300 ml flask sufficiently replaced with dry argon gas.
After cooling to 0 ° C., a solution of 56 mmol of 2,6-di-t-butyl-4-methylphenol in tetrahydrofuran 20 was added.
ml was added dropwise. After the dropping was completed, the reaction temperature was gradually raised to room temperature and the mixture was further stirred for 2 hours. The samarium (II) iodide has a molar concentration of 0.1 M in tetrahydrofuran solution 2
80 ml was added, and the mixture was stirred at room temperature for 6 hours. The precipitated tetrahydrofuran insolubles were removed by centrifugation, the tetrahydrofuran was distilled off, and the toluene-soluble portion was concentrated and recrystallized to obtain the desired product (BHT) ₂ Sm (thf), (BHT was 2,
6-di-t-butyl-4-methylphenoxide, thf
Represents tetrahydrofuran. same as below. ) Was obtained as purple crystals (yield 84%).

(Synthesis of Organoaluminum Compound) 100 ml of toluene was placed in a 200 ml flask sufficiently purged with dry argon gas and cooled to -78 ° C. there,
Trimethylaluminum-hexane solution (15 wt%)
Add 15 ml, then add 2,6-di-t through dropping funnel.
-Butyl-4-methylphenol (43.4 mmol)
Was added dropwise over 1 hour, and the reaction temperature was raised to room temperature with further stirring. After stirring at room temperature for 6 hours, the solvent was distilled off under reduced pressure to obtain a crude product of methylaluminum-bis- (2,6-di-t-butyl-4-methylphenoxide). Further, recrystallization from a toluene-hexane mixed solvent gave the desired product pure as colorless crystals (yield 92%).

[Example 1] (BHT) ₂ Sm synthesized by the above method as a polymerization initiator in a 60 ml Schlenk tube sufficiently replaced with dry argon gas.
19 ml of a toluene solution of (thf) ₄ (0.1 mmol) and methylaluminum-bis- (2,6-di-t-butyl-4-methylphenoxide) (0.38 mmol).
Was prepared and the temperature in the reaction vessel was adjusted to -7 using a magnetic stirrer.
The temperature was adjusted to 8 ° C. 1.0 ml of methyl methacrylate dried with calcium hydride and molecular sieve was added to this with a syringe. After stirring for 1 hour, a small amount of methanol was added to the reaction solution to stop the polymerization reaction.
The reaction solution was poured into a large amount of hexane to precipitate a polymer, which was filtered, washed, and dried, and then poly (methyl methacrylate) having a syndiotacticity of 42%, a heterotacticity of 10%, and an isotacticity of 48% was prepared.
0.83 g of MMA).

Example 2 Methylaluminum used-
The same procedure as in Example 1 was repeated except that the amount of bis- (2,6-di-t-butyl-4-methylphenoxide) was changed to 0.5 mmol, isotacticity 70%, heterotacticity 10%, syndiotactic. Ticity 20%
0.45 g of PMMA of was obtained.

[0029]

According to the present invention, a high molecular weight polymethacrylic ester having a desired stereoregularity can be obtained by changing the molar ratio of the metal compound constituting the polymerization initiator to the organoaluminum compound. This is a production method capable of controlling the thermal properties of the produced polymer, and is industrially extremely useful. The poly (meth) acrylic acid ester obtained by the present invention has little coloring and is excellent in heat resistance and can be used for films, sheets, coating materials and various molding materials.

Claims (1)

[Claims] 1. At least one metal compound represented by the following formula (I): (Wherein AX and Y represent a monovalent ligand, and A has an aromatic hydrocarbon residue or a halogen, silicon-containing group, nitrogen-containing group, sulfur-containing group, or phosphorus-containing group. A hydrocarbon residue having 1 to 20 carbon atoms, optionally having a substituent selected from the group consisting of an alkoxy group and an aryloxy group,
One or more A are hydrocarbon groups, silicon-containing groups, O,
It may be bonded via an N or S atom or may be bonded without a group. X is an O, NR, S atom;
Is a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms.
Y is a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a halogen atom. D is a solvent molecule. a, b, and c are integers of 0 ≦ a ≦ 4, 0 ≦ b ≦ 6, and 2 ≦ a + c ≦ 4, respectively. M represents a group IIIb or group IVb transition metal element of the periodic table. And a component comprising at least one organoaluminum compound as a polymerization initiator.