JPH11286525A - Production of isobutylene-based block copolymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To industrially advantageously obtain the subject copolymer having a regulated structure, without using a halogen polymerization solvent by reacting an isobutylene monomer with an aromatic vinyl compound monomer in the presence of a specific polymerization initiator. SOLUTION: This isobutylene-based block copolymer is obtained by reacting (B) a monomer consisting mainly of isobutylene with (C) a monomer consisting mainly of an aromatic vinyl compound (suitably an indene, or the like) in the presence of (A) a polymerization initiator expressed by the formula [R<1> is H or a 1-6C monovalent hydrocarbon; R<2> is a monovalent or a multi-valent aromatic hydrocarbon or the like; X is a halogen, a 1-6C alkoxyl or the like; (n) is 1-6] by using (D) at least one or more kinds of polymerization solvents consisting of compounds each not having a halogen atom (suitably, toluene, xylene, n-hexane, or the like). Further, as the component (A), it is preferable to use e.g. bis(1-chloro-1-methylethyl)benzene.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a block copolymer. More specifically, the present invention relates to a method for producing an isobutylene-based block copolymer having a controlled structure, comprising a polymer block mainly composed of isobutylene and a polymer block mainly composed of an aromatic vinyl compound.

[0002]

2. Description of the Related Art It is known that an isobutylene-based block copolymer can be obtained by a cationic polymerization method, and a 1,4 having a chlorine atom bonded to a tertiary carbon in the presence of a Lewis acid catalyst.
An inifer method using bis (α-chloroisopropyl) benzene or the like as a polymerization initiator has been developed (US-
RE34640). In the block copolymer synthesis using this cationic polymerization method, the simplex of the chain, that is, the growing chain is a carbon cation, and the stability is the initiator efficiency, the growth rate of the block, and the molecular weight and the molecular weight of the obtained polymer. It affects the polymerization characteristics such as the degree of dispersion and the physical properties of the product. The properties of the polymerization solvent, especially its dielectric constant, determine the stability of the cation. Generally, when polymer compounds are synthesized from vinyl compounds such as aliphatic olefins and styrene derivatives by cationic polymerization, the solubility and dielectric constant of the product In consideration of the above, a solvent containing a halogen compound is used.

In the synthesis of an isobutylene-based block copolymer comprising a polymer block containing isobutylene as a main component and a polymer block containing an aromatic vinyl compound as a main component, a compound having a halogen atom as a solvent (hereinafter, referred to as a solvent)
Polystyrene-polyisobutylene-containing a mixed solvent comprising a halogenated compound) and a compound having no halogen atom (hereinafter referred to as a non-halogen compound) as a polymerization solvent.
A method for polymerizing triblock copolymers of polystyrene is disclosed (US-RE 34640). The poly (α
-Methylstyrene) -polyisobutylene-poly (α-methylstyrene)
-Examples of polymerization using a mixed solvent consisting of hexane and chloromethane (Li et al. Macromolecules)
1995, 28, 4893-4898). Further, as an example of the triblock copolymer of polyindene-polyisobutylene-polyindene, there is a polymerization example using a mixed solvent composed of n-hexane and chloromethane as a polymerization solvent (Kennedy et al. Macromolecules).
1993, 26, 429-435).

[0004] However, chloromethane and dichloromethane, which have been used as solvents in the above-mentioned polymerizations, have been concerned about harm to living organisms in some parts, and it is said that emission control to the environment is necessary. I have. On the other hand, in the case of using an aromatic vinyl compound such as α-methylstyrene, p-methylstyrene, and indene, which is useful for improving heat resistance, when a solvent composed of a halogen compound is used, the structure is controlled. There was a tendency that it was difficult to obtain a block copolymer.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an industrially advantageous production method for obtaining an isobutylene-based block copolymer having a controlled structure without using a halogen compound as a polymerization solvent. is there.

[0006]

That is, the present invention provides a method for preparing a monomer (a) containing isobutylene as a main component and an aromatic vinyl compound in the presence of a polymerization initiator represented by the following general formula (1). A method for producing an isobutylene-based block copolymer, comprising reacting a monomer (b) as a main component, wherein the reaction comprises at least one polymerization solvent comprising a compound having no halogen atom. This is a method for producing an isobutylene-based block copolymer, which is used.

[0007]

Embedded image

(Wherein, a plurality of R ^{1 s} are the same or different and each represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms. R ² is a monovalent or polyvalent aromatic hydrocarbon group) Or 1
Represents a monovalent or polyvalent aliphatic hydrocarbon group. X represents a halogen atom, an alkoxyl group having 1 to 6 carbon atoms, or an acyloxyl group having 1 to 6 carbon atoms. n represents an integer of 1 to 6. When a plurality of Xs are present, they may be the same or different. The polymerization solvent is preferably at least one selected from the group consisting of toluene, xylene, n-hexane, heptane, cyclohexane, methylcyclohexane and ethylcyclohexane.

[0009] The polymerization solvent may be a mixed solvent in which two or more compounds having no halogen atom are used in combination.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. As the polymerization solvent used in the present invention, any compound which does not substantially inhibit cationic polymerization and has no halogen atom can be used without particular limitation. Examples of such a compound include aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, propylbenzene, and butylbenzene; and linear fatty acids such as ethane, propane, butane, pentane, hexane, heptane, octane, nonane, and decane. Group hydrocarbons, 2-methylpropane,
2-methylbutane, 2,3,3-trimethylpentane,
Examples thereof include branched aliphatic hydrocarbons such as 2,2,5-trimethylhexane, cycloaliphatic hydrocarbons such as cyclohexane, methylcyclohexane and ethylcyclohexane, and paraffin oil obtained by hydrogenating and purifying a petroleum fraction. it can.
Among them, toluene, xylene, pentane, hexane,
Heptane, octane, 2-methylpropane, 2-methylbutane, methylcyclohexane and ethylcyclohexane are preferred. Toluene, xylene, n-hexane, cyclohexane, heptane, methylcyclohexane and ethylcyclohexane are more preferred from the viewpoint of balance between polymerizability and solubility and availability.

These compounds are used alone or in combination of two or more as a polymerization solvent in consideration of the balance between the polymerization characteristics of the monomers constituting the block copolymer and the solubility of the resulting polymer. be able to. By using a combination of solvents, it becomes possible to control the polymerizability of the monomer to be reacted and to adjust the solubility of the resulting polymer.

[0012] The polymerization solvent is usually a C6-20
Using a mixed solvent of an aromatic hydrocarbon having 2 to 12 carbon atoms and an aromatic hydrocarbon having 6 to 20 carbon atoms and an aliphatic hydrocarbon having 2 to 12 carbon atoms in a range of 10: 0 to 2 : 8 is preferable from the viewpoint that the polymerization solvent mixed at a volume ratio of 8 is well-balanced in the solubility for the reactant and the product. When the number of carbon atoms exceeds the above range, evaporation of the polymerization solvent becomes difficult, and it tends to be difficult to take out the produced polymer. As the mixed solvent, a mixed solvent obtained by mixing toluene or xylene with an aliphatic hydrocarbon having 2 to 12 carbon atoms in a volume ratio of 10: 0 to 2: 8 is more preferable. Also,
The range of the dielectric constant and the solubility parameter of the polymerization solvent is such that the dielectric constant is 2-3 and the solubility parameter is 7.5-9.
It is preferably 3. More preferably, the dielectric constant is from 2 to 2.5 and the solubility parameter is from 7.5 to 9.1.

The amount of the polymerization solvent used is usually 1 to 50% by weight, preferably 5 to 35% by weight, in consideration of the viscosity of the obtained polymer solution and the ease of heat removal. It is set as follows.

The monomer of the present invention containing isobutylene as a main component means a monomer component containing 80% by weight or more of isobutylene, and the monomer containing an aromatic vinyl compound as a main component means an aromatic vinyl compound. It means a monomer component containing at least 80% by weight of a vinyl group compound.

As the aromatic vinyl monomer of the present invention, any aromatic vinyl monomer capable of cationic polymerization can be used without any particular limitation. Examples thereof include styrene, α-methylstyrene, p-methylstyrene, Examples include vinylnaphthalene, indene, and derivatives thereof. From the balance between the reactivity and the control of the molecular structure (for example, in the case of styrene, an indanyl ring is easily formed and the reaction is sometimes difficult to control).
Methylstyrene and indene are preferred, and indene is particularly preferred when using a polymerization solvent comprising a non-halogen compound.

Preferred combinations when the aromatic vinyl compound is a mixture include styrene / α-methylstyrene, styrene / indene, and styrene / α-methylstyrene / indene. For example, 0 to 95 mol% of styrene and 100 to 5 mol% of α-methylstyrene and / or indene
And the like.

Further, in the isobutylene-based block copolymer of the present invention, other cationically polymerizable monomers may be copolymerized as long as the polymerizability of the present invention is not impaired. Other cationically polymerizable monomers include aliphatic olefins,
Examples thereof include monomers such as aromatic vinyls, dienes, vinyl ethers, silanes, vinyl carbazole, β-pinene, acenaphthylene and the like. These can be used alone or in combination of two or more.

In the present invention, a Lewis acid catalyst may be used if necessary.
You can make it exist. Such Lewis acids include
Any material that can be used for thione polymerization, such as Ti
Cl _Four, TiBr_Four, BCl_Three, BF_Three, BF_Three・ OEt_Two,
SnCl_Four, SbCl_Five, SbF_Five, WCl₆, TaC
l_Five, VCl_Five, FeCl_Three, ZnBr_Two, AlCl_Three, A
lBr_ThreeAnd other metal halides; Et_TwoAlCl, EtA
lCl_TwoThe use of organometallic halides such as
Can be. Among them, catalyst ability, industrial availability
TiCl_Four, BCl_Three, SnCl_FourIs preferred
No.

In the present invention, the Lewis acid is generally used in an amount of 0.1 to 0.1 with respect to the compound represented by the following general formula (1).
Although it is used in a range of 100 times mol, a preferable amount is 0.1.
It is in the range of 3 to 50 times mol.

[0020]

Embedded image

(Wherein, a plurality of R ^{1 s} are the same or different and each represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms. R ² is a monovalent or polyvalent aromatic hydrocarbon group. Or 1
Represents a monovalent or polyvalent aliphatic hydrocarbon group. X represents a halogen atom, an alkoxyl group having 1 to 6 carbon atoms, or an acyloxyl group having 1 to 6 carbon atoms. n represents an integer of 1 to 6. When a plurality of Xs are present, they may be the same or different. ) Further, if necessary, an electron donor component may coexist. In the present invention,
As long as the electron donor component has 15 to 60 donors. Conventionally known ones can be used without limitation.
Preferred electron donor components include, for example, pyridines,
Examples include amines, amides, sulfoxides, or metal compounds having an oxygen atom bonded to a metal atom.

In the present invention, specific examples of the compound represented by the general formula (1) include the following compounds.

(1-chloro-1-methylethyl) benze
[C₆H_FiveC (CH_Three)_TwoCl], 1,4-bis (1-k
Rol-1-methylethyl) benzene [1,4-Cl (C
H _Three)_TwoCC₆H_FourC (CH_Three)_TwoCl], 1,3-bis (1
-Chloro-1-methylethyl) benzene [1,3-Cl
(CH_Three)_TwoCC₆H_FourC (CH_Three)_TwoCl], 1,3,5-
Tris (1-chloro-1-methylethyl) benzene
[1,3,5-((ClC (CH_Three)_Two)_ThreeC₆H_Three], 3
-Bis (1-chloro-1-methylethyl) -5- (te
rt-butyl) benzene [1,3-((C (CH_Three)_TwoC
1) 2-5- (C (CH_Three)_Three) C₆H_ThreeIn addition, bis (1-chloro-1-methylethyl) benzene
Is bis (α-chloroisopropyl) benzene, bis (2
-Chloro-2-propyl) benzene or dicum milk
Also called loride.

Of these, particularly preferred is bis (1-chloro-1-methylethyl) benzene [C ₆ H
₄ (C (CH ₃ ) ₂ Cl) ₂ ].

In the present invention, first, a monomer having isobutylene as a main component is polymerized in the presence of the compound represented by the general formula (1), and an isobutylene having a substituent (X) at a terminal is obtained. A block copolymer can also be synthesized by synthesizing a system polymer, isolating and purifying the polymer, and then polymerizing a monomer containing an aromatic vinyl compound as a main component.

The amount of each component can be appropriately designed depending on the characteristics of the target polymer. The molecular weight of the resulting polymer can be determined by the molar equivalent relationship between the monomer represented by the general formula (1) and the monomer composed mainly of isobutylene and the monomer composed mainly of the aromatic vinyl compound. A block copolymer having a number average molecular weight of, for example, about 20,000 to 500,000 can be easily produced.

The ratio of the monomer containing an aromatic vinyl compound as a main component of the block copolymer to the monomer containing isobutylene as a main component is not particularly limited. Monomers 5 to 8 mainly composed of compounds
0 parts by weight, and preferably 95 to 20 parts by weight of a monomer containing isobutylene as a main component, and 15 to 40 parts by weight of a monomer containing an aromatic vinyl compound as a main component and isobutylene as a main component. More preferably, it is composed of 85 to 60 parts by weight of the monomer.

Although the number average molecular weight of the isobutylene block copolymer of the present invention is not particularly limited, the number average molecular weight is preferably 30,000 to 500,000, more preferably 5,000.
0 to 400,000 is particularly preferred. Number average molecular weight is 3
If it is less than 0000, mechanical properties or the like may not be sufficiently exhibited, and if it is more than 500,000, the decrease in moldability or the like may be large.

The isobutylene-based block produced by the method of the present invention may be any one having a polymer block containing isobutylene as a main component and a polymer block containing an aromatic vinyl monomer as a main component. The molecular structure is not particularly limited, and may be, for example, any of block copolymers, diblock copolymers, triblock copolymers, and multiblock copolymers having a linear, branched, or star-like structure. Can also be selected. Preferred block copolymers include:
For example, an aromatic vinyl compound-based polymer block-isobutylene-based polymer block-aromatic vinyl compound-based polymer block-based triblock copolymer, aromatic vinyl compound A polymer block composed mainly of a polymer block-isobutylene as a main component, or a mixture thereof.

In carrying out the polymerization according to the production method of the present invention, each component is usually cooled, for example, at a temperature of -100 ° C to 0 ° C.
Mix at a temperature less than. In order to balance the energy cost with the stability of the polymerization, a particularly preferred temperature range is-
80 ° C to -30 ° C.

When a block copolymer is produced, a Lewis acid, a compound represented by the general formula (1), an electron donor component,
The method and order of addition of the monomer components and the like are not particularly limited, but preferred methods include, for example,
(A) a step of polymerizing a monomer containing isobutylene as a main component in the presence of an initiator system comprising a compound represented by the general formula (1) and a Lewis acid, and an electron donor component; A method comprising a step of adding a monomer containing an aromatic vinyl compound as a main component to the reaction system and polymerizing the same is exemplified. In this case, the polymer may be once isolated and purified after the step (A), or the step (B) may be continuously performed without isolation.

[0032]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples, and can be appropriately modified and implemented within the scope of the invention. .

The properties of the polymer were measured according to the following methods. (1) Number average molecular weight (Mn) and molecular weight distribution (Mw / Mn) of polymer Measured by gel permeation chromatography (GPC). Using a Waters 510 type GPC system, chloroform was used as the mobile phase, and the measurement was performed at a polymer concentration of 2 mg / ml and a column temperature of 35 ° C. The number average molecular weight and molecular weight distribution were calculated using polystyrene as a standard sample.

Example 1 (Synthesis of indene-isobutylene block copolymer) 5
After the inside of the polymerization vessel of the 00 mL separable flask was replaced with nitrogen, 40 mL of n-hexane (dried with molecular sieves) and 160 mL of toluene (dried with molecular sieves), 160 mL of p-dicimyl chloride 0 were added using a syringe. 0.0876 g (0.38 mmol)
Was added (dielectric constant of polymerization solvent 2.3, solubility parameter 8.6: calculated value). After cooling the polymerization vessel in a dry ice / methanol bath at -70 ° C, 0.0708 g (0.76 mmol) of 2-methylpyridine was added. Next, 38.3 mL of the isobutylene monomer (474 m
mol.) was connected to a pressure-resistant glass liquefaction sampling tube equipped with a three-way cock, and an isobutylene monomer was fed into the polymerization vessel under nitrogen pressure. Further, 1.50 mL (13.7 mmol) of titanium tetrachloride was added to initiate polymerization. After stirring at the same temperature for 1 hour from the start of the polymerization, subsequently, 11.4 g of indene monomer (98.1 mmol) previously cooled to -70 ° C.
1, a mixed solution of 16 mL of toluene and 4 mL of n-hexane) was added to the polymerization vessel. About 10 minutes after the addition of the indene monomer, about 10 mL of methanol was added to terminate the reaction. After the solvent and the like were distilled off from the reaction solution, it was dissolved in toluene and washed twice with water. Further, a toluene solution was added to a large amount of methanol to precipitate a polymer,
The obtained polymer was vacuum-dried at 60 ° C. for 24 hours to obtain a polymer. The obtained polymer was a rubber-like elastic body, and no stickiness or the like was observed on the surface. As a result of fractionation analysis, the ratio of the indene-isobutylene block copolymer was 70%, the isobutylene homopolymer was 27%,
It was suggested that 3% of the indene homopolymer was formed. In addition, Mn of the obtained polymer was 75,000 and Mw /
Mn was 1.39.

Comparative Example 1 (Synthesis of indene-isobutylene block copolymer) 5
After replacing the inside of the polymerization vessel of the 00 mL separable flask with nitrogen, 120 mL of dichloromethane (dried with molecular sieves) and 80 mL of n-hexane (dried with molecular sieves) using a syringe,
0.0876 g of p-dicumyl chloride (0.38 mm
ol). Dry the polymerization vessel at -70 ° C dry ice /
After cooling in a methanol bath, 0.0354 g (0.38 mmol) of 2-methylpyridine was added. Next, 38.3 mL of isobutylene monomer (474 mmol
A leffusion tube made of Teflon was connected to a pressure-resistant glass liquefaction sampling tube equipped with a three-way cock containing l), and an isobutylene monomer was sent into the polymerization vessel by nitrogen pressure. Further, 0.75 mL (6.9 mmol) of titanium tetrachloride was added to initiate polymerization. After stirring at the same temperature for 1 hour from the start of the polymerization, 11.4 g of indene monomer previously cooled to -70 ° C (added as a mixed solution of 98.1 mmol, 12 mL of dichloromethane and 8 mL of n-hexane) Was added into the polymerization vessel. About 10 minutes after the addition of the indene monomer, about 10 mL of methanol was added to terminate the reaction. After the solvent and the like were distilled off from the reaction solution, it was dissolved in toluene and washed twice with water. Further, a toluene solution was added to a large amount of methanol to precipitate a polymer,
The obtained polymer was vacuum-dried at 60 ° C. for 24 hours to obtain a polymer. The obtained polymer was non-uniform and poor in rubber-like elasticity, and stickiness was observed on the surface. As a result of fractionation analysis, the ratio of the indene-isobutylene block copolymer was 20%, and the isobutylene homopolymer was 65%.
%, That is, 15% of indene homopolymer was produced.

As described above, as shown in the first embodiment,
A good indene-isobutylene block copolymer can be obtained in a solvent that does not use a halogen compound.

[0037]

According to the present invention, an isobutylene-based block copolymer having a controlled structure can be produced without using a polymerization solvent comprising a halogen compound, and is particularly useful when heat resistance is required. In addition, it is possible to provide a method for producing an isobutylene-based block copolymer which is industrially extremely advantageous in that no halogen compound is used.

Claims (8)

[Claims] 1. A monomer (a) containing isobutylene as a main component and a monomer (b) containing an aromatic vinyl compound as a main component in the presence of a polymerization initiator represented by the following general formula (1). ), The isobutylene-based block copolymer being produced by reacting at least one polymerization solvent comprising a compound having no halogen atom. A method for producing a copolymer. Embedded image (Wherein, a plurality of R ¹ are the same or different, .R ² representing a monovalent hydrocarbon group having a hydrogen atom or 1 to 6 carbon atoms, 1
Represents a monovalent or polyvalent aromatic hydrocarbon group or a monovalent or polyvalent aliphatic hydrocarbon group. X represents a halogen atom, an alkoxyl group having 1 to 6 carbon atoms, or an acyloxyl group having 1 to 6 carbon atoms. n represents an integer of 1 to 6. When a plurality of Xs are present, they may be the same or different. ) 2. The polymerization solvent is toluene, xylene, n-
The method for producing an isobutylene-based block copolymer according to claim 1, which is at least one selected from the group consisting of hexane, heptane, cyclohexane, methylcyclohexane, and ethylcyclohexane. 3. The method for producing an isobutylene-based block copolymer according to claim 1, wherein the polymerization solvent is a mixed solvent in which two or more compounds having no halogen atom are used in combination. 4. A polymerization solvent comprising an aromatic hydrocarbon having 6 to 20 carbon atoms and an aliphatic hydrocarbon having 2 to 12 carbon atoms in a ratio of 10: 0.
2. A mixed solvent mixed at a volume ratio of about 2: 8.
Or a method for producing an isobutylene-based block copolymer according to item 3. 5. The method for producing an isobutylene-based block copolymer according to claim 4, wherein the aromatic hydrocarbon having 6 to 20 carbon atoms is toluene and / or xylene. 6. An aliphatic hydrocarbon having 2 to 12 carbon atoms, wherein n is
The method for producing an isobutylene-based block copolymer according to claim 4, wherein the block copolymer is at least one selected from the group consisting of hexane, heptane, cyclohexane, methylcyclohexane, and ethylcyclohexane. 7. The method according to claim 1, wherein the monomer (b) containing an aromatic vinyl compound as a main component is at least one selected from the group consisting of α-methylstyrene, p-methylstyrene and indene. A method for producing an isobutylene-based block copolymer. 8. The method for producing an isobutylene-based block copolymer according to claim 7, wherein the monomer (b) mainly containing an aromatic vinyl compound is indene.