JPH11209429A - Production of alkoxystyrene polymer and alkoxystyrene polymer obtained thereby - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing in high yields an alkoxystyrene polymer having a number-average molecular weight of 10,000 or above and such a narrow molecular weight distribution as to correspond to an Mw/Mn ratio of 1.10 or below by utilizing anion living polymerization. SOLUTION: This process comprises the steps of: mixing an alkoxystyrene with an anionic polymerization initiator in a hydrocarbon solvent containing a Lewis base at a temperature below the polymerization initiation temperature, and polymerizing the resultant mixture by heating. It is desirable that the step of polymerizing the resultant mixture by heating is followed by the step of adding another monomer to the reaction product and the step of subjecting the entire mixture to block copolymerization.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing an alkoxystyrene polymer as a photosensitive material,
More specifically, the present invention relates to a method for producing an alkoxystyrene polymer having a number average molecular weight of 10,000 or more and a narrow molecular weight distribution.

[0002]

2. Description of the Related Art An alkoxystyrene polymer can be converted into a vinylphenol polymer by the action of an acid. This reaction is known as a primary hydroxyl group deprotection reaction. Therefore, if a photoacid generator is contained in the alkoxystyrene polymer and light is irradiated, it is possible to convert a hydrophobic alkoxystyrene polymer into a hydrophilic vinylphenol polymer by a so-called chemical amplification effect.
This conversion of physical properties by light can be used for a photoresist or a light adhesive. For example, Color Material Association Journal 67
[7], 449 (1994),
For the processing of LSIs with an increased degree of integration, chemically amplified photoresists are promising, and among them, alkoxystyrene polymers are expected as high-resolution photoresists. Further, the hydroxyl group of the vinylphenol polymer after the conversion can be converted into various other functional groups by a polymer reaction. These alkoxystyrene polymers preferably have a relatively high molecular weight and a narrow molecular weight distribution in terms of mechanical strength, adhesion to an adherend, solvent resistance, and resolution.

Living polymers are generally effective for producing polymers having a narrow molecular weight distribution. In living polymerization, the molecular weight of the polymer to be produced in advance is calculated as {monomer amount (mol) / initiator amount (mol)} ×
It can be controlled to the molecular weight calculated by (molecular weight of monomer). Furthermore, since the active terminal of the polymer is "living" even after the polymerization is completed, a block copolymer with another monomer can be produced. Also in this case, the molecular weight of each segment of the block copolymer to be produced in advance is expressed by the formula: ｛monomer amount (mol) / active terminal group amount (m
ol)｝ × (molecular weight of monomer). Furthermore, since the active terminal of the polymer is still alive after the polymerization is completed, it is possible to prepare various block copolymers with other monomers, and to introduce a functional group into the terminal of the block copolymer.

[0004] However, it is generally known that the presence of a polar group such as an alkoxy group lowers the living property due to a side reaction. Here, as one of the evaluation criteria of the living property, the ratio Mw / Mn between the weight average molecular weight (Mw) and the number average molecular weight (Mn) is called a molecular weight distribution and is often used. This molecular weight distribution Mw / Mn is 1.10
When it is smaller, it may be considered that ideal living polymerization has progressed. If Mw / Mn is greater than 1.10, it can be determined that the living property is low.

As a method for producing an alkoxystyrene polymer having a narrow molecular weight distribution using anionic living polymerization,
JP-B-63-36602 describes that anion polymerization of a p-tert-butoxystyrene monomer was performed using sec-butyllithium as a polymerization initiator and benzene as a solvent. The publication does not disclose any essential polymerization conditions such as polymerization temperature and polymerization time, but it is generally known that the progress of anionic living polymerization in a hydrocarbon solvent such as benzene is slow, When a solvent is used, the polymerization temperature is usually increased to promote the reaction. However, p-ter
Since the t-butoxystyrene monomer has not only a vinyl group in the styrene portion but also a tert-butoxy group at the p-position, when the polymerization temperature is increased, a side reaction occurs during the polymerization reaction, and a normal reaction using n-butyllithium is performed. In practice, anionic polymerization has a problem that the monodispersity is low, that is, the living property is low. Furthermore, sec-
Butyllithium is excellent in reactivity, but has a cost disadvantage that it is more expensive than n-butyllithium generally used in anionic polymerization, and furthermore, it must be stored at a low temperature. It also has the above disadvantages.

The publication also discloses that styrene monomer and p-
There is a description that tert-butoxystyrene monomer was charged in two steps and block copolymerized. However, the publication does not specifically describe the molecular weight distribution Mw / Mn, and does not describe polymerization conditions such as polymerization temperature and polymerization time at all. In our experiments, a side reaction occurred even when the styrene monomer and the p-tert-butoxystyrene monomer were charged in two steps, and a block copolymer having a narrow molecular weight distribution could not be obtained.

JP-A-3-277608 discloses that an alkali metal such as sodium or potassium is used as a polymerization initiator, and a p-tert-butoxystyrene monomer is slowly dropped into a THF solution in which the initiator is dissolved to form an anion. A method for producing a polymer by polymerization has been proposed. The publication also discloses THF in which an initiator is dissolved.
A method of preparing a block copolymer of butadiene and p-tert-butoxystyrene by slowly dropping a butadiene monomer into the solution and performing anionic polymerization and then slowly dropping a p-tert-butoxystyrene monomer and performing anionic polymerization is proposed. Have been. However, according to this method, a polymer having a molecular weight distribution smaller than Mw / Mn = 1.10, that is, a so-called monodisperse polymer cannot be obtained. Further, in general, the anionic living polymerization in a polar solvent such as THF progresses rapidly and is accompanied by heat generation. Therefore, it is usual to drop the monomer at an extremely low temperature. However, the monomer is added to a THF solution in which an initiator is dissolved. There is a drawback that it takes a long time to drop, and a longer time is required to complete the polymerization. Alkali metals such as sodium have a problem in storage stability, and have a drawback in that oxygen dissolved in a dispersion medium forms an oxide on the metal surface and reduces the activity.

JP-A-6-298869 discloses that a hydrocarbon solvent is used as a polymerization solvent, and tetrahydrofuran is added to the solvent in an amount of 0.2 to 10% by weight, and
A method of anionic polymerization with butyllithium has been proposed. However, in this method, the number average molecular weight Mn is 1
When the molecular weight is 0000 or less, a polymer having a narrow molecular weight distribution of Mw / Mn = 1.10 or less can be obtained. However, if a polymer having a number average molecular weight of 10,000 or more is obtained, the reason is not clear. However, there is a disadvantage that the molecular weight distribution is widened and the living property is deteriorated. Further, as described above, sec-butyllithium used as a polymerization initiator has a cost disadvantage that the price is higher than n-butyllithium generally used in anionic polymerization, and at a low temperature. It also has the disadvantage of handling that it must be preserved.

As described above, a method for producing an alkoxystyrene polymer having a number average molecular weight of 10,000 or more and a narrow molecular weight distribution has not been established at present.

[0010]

Accordingly, a first object of the present invention is to utilize anionic living polymerization to obtain a number average molecular weight of 10,000 or more and a molecular weight distribution of Mw / Mn.
It is an object of the present invention to provide a method for producing an alkoxystyrene polymer capable of producing an alkoxystyrene polymer having a narrow molecular weight distribution of 1.10 or less in high yield. A second object of the present invention is to provide a method for producing an alkoxystyrene polymer in which n-butyllithium generally used in anionic polymerization can be used as a polymerization initiator. A third object of the present invention is to add another monomer to an alkoxystyrene living polymer so that the molecular weight distribution is Mw / Mn = 1.
An object of the present invention is to provide a method for producing an alkoxystyrene polymer which can produce a block copolymer having a narrow molecular weight distribution of 10 or less in high yield.

[0011]

Means for Solving the Problems As a result of intensive studies, the present inventors have found a method for producing an alkoxystyrene polymer which can achieve the above object, and have completed the present invention. That is, the present invention has a step of mixing alkoxystyrene and an anionic polymerization initiator in a hydrocarbon solvent containing a Lewis base at a temperature lower than the polymerization initiation temperature, and a step of heating and polymerizing the mixture. This is a method for producing an alkoxystyrene polymer.

In the conventional production method, the polymerization reactivity of the anion generated by the polymerization initiator has been increased by increasing the polarity of the solvent. However, the higher the polymerization reactivity of the anion, the greater the heat generation. In order to suppress the heat generation during this reaction, the rate of addition of the monomer is reduced,
It is necessary to lower the reaction temperature. Therefore, in the conventional production method, the number average molecular weight is 10,000 or more,
The reason why an alkoxystyrene polymer having a narrow molecular weight distribution with a molecular weight distribution of Mw / Mn = 1.10 or less has not been obtained is that when the polarity of the solvent is increased and the polymerization reaction rate is increased, individual anion It is presumed that the difference in the generation time of living occurs, which has a large effect on the molecular weight distribution of the polymer. That is, the molecular weight of the polymer increases in proportion to the reaction time, and the previously generated anion living gives a polymer with a higher molecular weight.

On the other hand, the feature of the present invention is that an alkoxystyrene monomer is dissolved in a hydrocarbon solvent in which a Lewis base such as tetrahydrofuran is present, and an anionic polymerization initiator is added at a temperature at which polymerization is not substantially started. After that, it is heated and polymerized. That is, the presence of a Lewis base in the hydrocarbon solvent increases the polymerization reactivity of the anion, and at a temperature lower than the polymerization initiation temperature, to mix the alkoxystyrene monomer and the polymerization initiator to form a uniform system, Thereafter, by raising the temperature, anion living can be simultaneously generated, and it is considered that an alkoxystyrene polymer having a high molecular weight and a narrow molecular weight distribution can be obtained. As described above, the concept of controlling the generation time of the anion living has not existed conventionally.

The method for producing an alkoxystyrene polymer of the present invention is an ideal living anionic polymerization. According to the present invention, a polymer having a number average molecular weight of 10,000 or more has a molecular weight distribution of Mw / Mn = 1.10. The following polymers having a very narrow molecular weight distribution can be produced in high yield.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As Lewis bases, ethers such as tetrahydrofuran, 1,4-dioxane, ethyl ether, trimethylamine, triethylamine, N
Tertiary amines such as -methylpyrrolidine can be used.
Among them, addition of tetrahydrofuran is particularly effective. The amount of addition is 0.1% by weight or more to the
% By weight, preferably 0.5% by weight or more and 5% by weight or less.

The reason why the Lewis base is added to the solvent is as follows.
Advanced Polymer S issued in 1983
Michael published in Science Volume 49
Szwarc's paper "Living Polymers"
and Mechanism of Anionic
This is because, as described in Polymerization, paragraphs 67 to 68, a Lewis base such as tetrahydrofuran has an effect of accelerating the polymerization initiation reaction. Also in the present invention, the addition of the Lewis base has the effect of accelerating the initiation reaction rate during heating and narrowing the molecular weight distribution.

As the hydrocarbon solvent, aliphatic hydrocarbon compounds such as methylcyclohexane, ethylcyclohexane and cyclohexene, and aromatic hydrocarbon compounds such as benzene, toluene, xylene and alkylnaphthalene can be used. Among them, methylcyclohexane and toluene having a relatively low boiling point are preferable because the solvent can be easily reused after the reaction.

In the present invention, living anionic polymerization is carried out using alkoxystyrene as a monomer. The alkoxystyrene of the present invention is represented by the following general formula (1),

[0019]

Embedded image

In the formula, R ₁ , R ₂ and R ₃ have 1 to 12 carbon atoms.
Is an alkyl group. R ₁ ,
R ₂ and R ₃ are preferably an alkyl group having 1 to 3 carbon atoms,
Specifically, it is preferable to use an alkoxystyrene having a boiling point of 300 ° C. or less at normal pressure, such as p-tert-butoxystyrene, as a monomer.

In the present invention, n-butyllithium, sec-butyllithium, tert-butyllithium, n-butyllithium, and the like are used as polymerization initiators for anionic polymerization of the alkoxystyrene monomer represented by the general formula (1). Known organic metal compounds used in living anionic polymerization such as sodium naphthalene, lithium naphthalene, sodium anthracene, and α-methylstyrene tetramer sodium can be used.However, it is more preferable to use n-butyllithium in terms of price and handling. preferable.

The solvents, monomers and additives used are
Prior to the polymerization, it is preferable to remove impurities and perform distillation under reduced pressure using a fractionating tube or the like in the presence of a desiccant before use. As the drying agent, a drying agent used in ordinary anionic polymerization can be used. For example, sodium, lithium aluminum hydride, calcium hydride, molecular sieves, silica gel, activated alumina, phosphorus pentoxide, barium oxide and the like can be used.

In the method for producing an alkoxystyrene polymer of the present invention, a step of mixing an alkoxystyrene monomer and an anionic polymerization initiator in a hydrocarbon solvent containing a Lewis base at a temperature lower than the polymerization initiation temperature (hereinafter, a mixing step) ) And a step of heating and polymerizing the mixture (hereinafter, referred to as “polymerization”).
This is called a polymerization step. ).

In the mixing step, the temperature lower than the polymerization initiation temperature refers to the temperature in a state where the initiator reacts with the alkoxystyrene monomer and substantially no alkoxystyryl anion as an active species is substantially produced. This refers to the temperature at which the reaction solution is colorless and transparent without coloration due to styryl anion. Specifically, for example,
In the case of n-butyllithium, the reaction system is brought to a temperature of -50C or lower, preferably -55C or lower.

The mixing method is not particularly limited. The alkoxystyrene monomer may be dissolved in a hydrocarbon solvent containing a Lewis base, and an anionic polymerization initiator may be added thereto. The anionic polymerization initiator may be dissolved in the hydrocarbon solvent present, and the alkoxystyrene monomer may be added thereto. In addition, an anionic polymerization initiator was dissolved in a hydrocarbon solvent in which a Lewis base was present, and a portion of the alkoxystyrene monomer was added at a temperature lower than the polymerization initiation temperature, and after heating, the remaining monomers were added. To polymerize.

In the polymerization step, the heating temperature, that is, the polymerization temperature is not particularly limited as long as it is equal to or higher than the polymerization initiation temperature, and is optimized in relation to the reaction time. In particular,
For example, in the case of n-butyllithium, the polymerization is carried out by heating to a temperature of -50C or higher, preferably -20C or higher. If the temperature is lower than −50 ° C., the yield of the polymer will be poor.

The concentration of the alkoxystyrene monomer is 1% by weight or more and 50% by weight or less, preferably 5% by weight or more and 40% by weight or less based on the hydrocarbon solvent containing the Lewis base. If it exceeds 50% by weight, the solution viscosity increases,
This is because a side reaction easily occurs, and if the amount is less than 1% by weight, productivity is reduced.

In order to prevent the reaction with moisture, oxygen and the like, the polymerization is preferably carried out under a high vacuum or in an inert gas atmosphere such as a high-purity nitrogen gas or argon gas.

The termination of the polymerization may be effected by adding a general terminator such as water, methyl alcohol, ethyl alcohol or isopropyl alcohol to the reaction system. When the terminator is added, the black color of the polymer solution caused by the alkoxystyryl anion disappears instantaneously, so that it is easily understood that the polymer solution is stopped. Furthermore, if a polyfunctional coupling agent such as dichlorosilane or tetrachlorosilane is used, the polymerization can be stopped, and at the same time, the polymer chain can be extended and a branched polymer can be formed.

After termination of the polymerization reaction, the polymer solution can be dissolved in a solvent in which monomers such as methyl alcohol, ethyl alcohol, and isopropyl alcohol are dissolved but the polymer is hardly dissolved, and the polymer can be separated by precipitation. Prior to this operation, the stopped polymer solution may be washed with ion-exchanged water or distilled water to remove trace amounts of ionic substances.

Another feature of the present invention is that a block copolymer is prepared by utilizing the fact that the alkoxystyrene polymerized as described above is an ideal living polymer. That is, after the alkoxystyrene monomer is polymerized by the above-described method, the second monomer is added without stopping the polymerization to produce a block copolymer. Examples of monomers copolymerizable with the alkoxystyrene monomer include conjugated dienes such as 1,3 butadiene and isoprene, vinyl aromatic compounds such as styrene, α-methylstyrene, p-methylstyrene, and p-butylstyrene; And (meth) acrylates such as methyl acrylate, ethyl (meth) acrylate and butyl (meth) acrylate.

The alkoxystyrene polymer of the present invention is obtained by the above-mentioned production method. A polymer having a number average molecular weight of 10,000 or more has a molecular weight distribution of Mw / Mn.
It is a polymer having an extremely narrow molecular weight distribution of = 1.10 or less.

[0033]

【Example】

(Example 1) p-tert-butoxystyrene was washed with a 10% by weight aqueous solution of sodium hydroxide,
After thoroughly washing with distilled water, it was pre-dried with magnesium sulfate. Next, magnesium sulfate was filtered off, calcium hydride was added, and the mixture was distilled under reduced pressure. After 28 g (0.16 mol) of p-tert-butoxystyrene thus purified and calcium hydride were added and refluxed,
150 g of toluene purified by distillation under reduced pressure and 0.60 g of purified tetrahydrofuran (8.3 × 10 ⁻³ mol)
Was dried sufficiently in advance under a nitrogen atmosphere.
of glass reaction vessels. The reaction solution was cooled to −58 ° C. with stirring, and 1.2 ml (1.9 × 10 ⁻³ mol) of a 1.6 mol / liter n-butyllithium hexane solution (manufactured by Wako Pure Chemical Industries, Ltd.) was added thereto. ) Was injected with a syringe. At this time, the reaction solution was colorless and transparent. Next, when this reaction system was heated to −15 ° C., the reaction solution became −5 ° C.
The color turned pale yellow between 5 ° C and -50 ° C, and subsequently turned black. After the reaction at −15 ° C. for 3 hours, methanol was added to stop the reaction. When methanol was added, the black color of the reaction solution disappeared instantaneously. The reaction solution was poured into isopropanol to precipitate a white polymer. The white polymer was filtered off and dried in vacuum at 80 ° C. to obtain 27 g of a p-tert-butoxystyrene polymer (yield 96%). The molecular weight and distribution were determined from the GPC elution curve. Mn = 15000, Mw / Mn = 1.
04, which was extremely high in monodispersity.

(Example 2) As in Example 1, 150 g of purified and dried toluene and 0.6 g of tetrahydrofuran were used.
0 g (8.3 × 10 ⁻³ mol) was placed in a 500 ml glass reaction vessel. The reaction system was cooled to −78 ° C. with stirring, and 1.2 ml of a 1.6 mol / l n-butyllithium hexane solution (manufactured by Wako Pure Chemical Industries, Ltd.) (1.9 × 1)
0 ^-3 mol) was injected into the reaction system with a syringe. Subsequently, p-tert-butoxystyrene 5 purified in the same manner as in Example 1
g (2.8 × 10 ^-2 mol) was injected with a syringe. At this time, the reaction system was colorless and transparent. Next, this reaction system is
When heated to 40 ° C., the reaction solution was changed from −55 ° C. to −5 ° C.
The color turned pale yellow at 0 ° C., and then turned black. -4
While maintaining the temperature at 0 ° C, an additional 20 g (0.11 mol) of p-tert-butoxystyrene was added dropwise over 1 hour. After completion of the dropwise addition, the reaction was further performed at -15 ° C for 3 hours, and then methanol was added to stop the reaction. After washing the reaction solution with 200 g of ion-exchanged water, the toluene layer was poured into isopropanol to precipitate a white polymer. The white polymer was filtered off and dried in vacuum at 80 ° C.
g of p-tert-butoxystyrene polymer was obtained (96% yield). When the molecular weight and distribution were determined from the GPC elution curve, Mn = 13000 and Mw / Mn = 1.06, which were extremely high in monodispersity.

Comparative Example 1 1.6 mol / liter of n-
Butyllithium hexane solution (Wako Pure Chemical Industries) 1.2m
1 (1.9 × 10 ⁻³ mol) was injected into the reaction system at −78 ° C., and reacted exactly as in Example 1 except that the reaction was carried out at −78 ° C. as it was. When this reaction solution was poured into isopropanol, no polymer was precipitated.

Comparative Example 2 1.6 mol / liter of n-
Butyllithium hexane solution (Wako Pure Chemical Industries) 1.2m
1 (1.9 × 10 ⁻³ mol) was injected into the reaction system at −15 ° C., and reacted exactly as in Example 1 except that the reaction was carried out at −15 ° C. to obtain 26 g of p-tert- A butoxystyrene polymer was obtained (93% yield). The molecular weight and distribution were determined from the GPC elution curve. Mn = 220
00, Mw / Mn = 1.24, and the molecular weight distribution was broad.

Comparative Example 3 28 g (0.16 mol) of p-tert-butoxystyrene purified in the same manner as in Example 1 and 150 g of purified tetrahydrofuran were previously thoroughly dried under a nitrogen atmosphere in a 300 ml volume of 300 ml. It was placed in a glass reaction vessel. The reaction system was cooled to −78 ° C. while stirring, and a 1.6 mol / l n-butyllithium hexane solution (manufactured by Wako Pure Chemical Industries, Ltd.) was added thereto.
2 ml (1.9 × 10 ⁻³ mol) were injected with a syringe. At this point, the reaction turned orange. Next, the reaction system was heated to −15 ° C. and reacted for 3 hours, and then methanol was added to stop the reaction. The reaction solution was poured into isopropanol to precipitate a white polymer. The white polymer was filtered off and dried in vacuum at 80 ° C. to obtain 27 g of pt.
tert-butoxystyrene polymer was obtained (yield: 96).
%). When the molecular weight and distribution were determined from the GPC elution curve, Mn was 33,000 and Mw / Mn was 1.89.
Monodispersity was low.

Comparative Example 4 p-tert-butoxystyrene was washed with a 10% by weight aqueous solution of sodium hydroxide.
After thoroughly washing with distilled water, it was pre-dried with magnesium sulfate. Next, magnesium sulfate was filtered off, calcium hydride was added, and the mixture was distilled under reduced pressure. After 28 g (0.16 mol) of p-tert-butoxystyrene thus purified and calcium hydride were added and refluxed,
150 g of benzene purified by distillation under reduced pressure and 0.60 g of purified tetrahydrofuran (8.3 × 10 ⁻³ mol)
Was dried sufficiently in advance under a nitrogen atmosphere.
of glass reaction vessels. The reaction solution was cooled to 7 ° C. close to the melting point of benzene (5.5 ° C.) while stirring, and 1.6 ml (1%) of a 12% by weight sec-butyllithium hexane solution (manufactured by Kemeta Japan) was added thereto. .
9 × 10 ⁻³ mol) was injected with a syringe. After the reaction was continued at 7 ° C. for 3 hours, methanol was added to stop the reaction. When methanol was added, the black color of the reaction solution disappeared instantaneously. This reaction solution is poured into isopropanol,
A white polymer was precipitated. The white polymer was filtered off and dried in vacuum at 80 ° C. to obtain 27 g of a p-tert-butoxystyrene polymer (yield 96%). The GPC elution curve had several peaks in addition to the sharp peak, indicating that the obtained polymer was polydisperse. The molecular weight and distribution obtained from the GPC elution curve were Mn = 38000, which was larger than the molecular weight calculated from {monomer amount (mol) / initiator amount (mol)} × (monomer molecular weight). Thus, in benzene,
Polymerization using -butyllithium did not result in an ideal living polymerization.

Example 3 28 g (0.16 mol) of p-tert-butoxystyrene purified in the same manner as in Example 1, 150 g of toluene and 0.1 g of tetrahydrofuran.
60 g (8.3 × 10 ^-3 mol) was placed in a 300 ml glass reaction vessel which had been sufficiently dried in advance under a nitrogen atmosphere. The reaction system was cooled to −58 ° C. with stirring, and 1.2 ml of a 1.6 mol / liter n-butyllithium hexane solution (manufactured by Wako Pure Chemical Industries, Ltd.) (1.9 ×
10 ^-3 mol) was injected with a syringe. At this time, the reaction solution was colorless and transparent. Next, when this reaction system was heated to −15 ° C., the reaction solution turned pale yellow between −55 ° C. and −50 ° C., and subsequently turned black. -15
After the reaction at 3 ° C. for 3 hours, the temperature was once lowered to −58 ° C., and 17 g (0.16 mol) of the purified styrene monomer was added thereto and reacted again at −15 ° C. for 3 hours. After completion of the reaction, the reaction was stopped by adding methanol. When methanol was added, the black color of the reaction solution disappeared instantaneously. The reaction solution was poured into isopropanol to precipitate a white polymer. The white polymer was filtered off and dried in vacuo at 80 ° C. to obtain 44 g of a block polymer composed of p-tert-butoxystyrene and styrene (yield 98%). G
When the molecular weight and distribution were determined from the PC elution curve, Mn was obtained.
= 24000 and Mw / Mn = 1.09, which were extremely monodisperse.

Comparative Example 5 6 mol / liter n
-Butyl lithium hexane solution (manufactured by Wako Pure Chemical Industries) 1.2
ml (1.9 × 10 ⁻³ mol) was injected into the reaction system at −15 ° C., and reacted exactly as in Example 3 except that the reaction was carried out at −15 ° C., and 32 g of p-tert- A butoxystyrene polymer styrene block copolymer was obtained (yield 71%). The molecular weight and distribution were determined from the GPC elution curve. Mn = 42000, Mw / Mn = 1.28
And the molecular weight distribution was broad.

The results of the above Examples and Comparative Examples are shown in Table 1 together with design values of molecular weight (number average molecular weight Mn).

[0043]

[Table 1]

From Examples 1 and 2, according to the production method of the present invention, ideal anion living polymerization can be carried out, the number average molecular weight is 10,000 or more, and the molecular weight distribution is Mw / Mn = 1.10. It can be seen that an alkoxystyrene polymer having the following narrow molecular weight distribution can be produced in high yield. Further, it can be seen that n-butyllithium can be used in the manufacturing method. On the other hand, if the temperature is lower than the polymerization initiation temperature (-78 ° C. in the case of n-butyllithium), the polymerization reaction does not proceed at all (Comparative Example 1). When the initiator is mixed, the molecular weight distribution is widened (Comparative Example 2), and when the reaction solvent is only THF which is a polar solvent, the monodispersity is reduced (Comparative Example 3). In addition, as described in JP-B-63-36602, polymerization using sec-butyllithium in benzene did not result in an ideal living polymerization and was polydisperse (Comparative Example 4). .

From Example 3, according to the production method of the present invention, by adding another monomer to the alkoxystyrene living polymer, the molecular weight distribution becomes Mw / Mn = 1.10.
It can be seen that a block copolymer having the following narrow molecular weight distribution can be produced in high yield. On the other hand, when the alkoxystyrene and the anionic polymerization initiator were mixed at a temperature equal to or higher than the polymerization initiation temperature, it was found that the molecular weight distribution was expanded (Comparative Example 5).

[0046]

The method for producing an alkoxystyrene polymer of the present invention is an ideal living anionic polymerization, and a polymer having a number average molecular weight of 10,000 or more has a molecular weight distribution of Mw.
A polymer having an extremely narrow molecular weight distribution of /Mn=1.10 or less can be produced in high yield. That is, the production method of the present invention has a very high living property, and the molecular weight of the polymer to be produced or the molecular weight of each segment of the block copolymer is calculated by the following formula: (monomer amount (mol) / initiator amount (mol)) It can be controlled to the molecular weight calculated by｝ × (molecular weight of monomer). Therefore, according to the production method of the present invention, a polymer having a desired molecular weight can be produced with high accuracy. Further, as a polymerization initiator to be used, n-butyllithium generally used in anionic polymerization can be used, and it is not necessary to use sec-butyllithium which has a disadvantage in terms of cost and handling. In addition, the present invention applies not only a method in which a reaction is allowed to proceed while dropping a monomer into a reaction solution in which an initiator is dissolved in advance, but also a method in which an initiator is charged into a reaction solution in which a monomer is dissolved in advance and reacted at a stroke. As a result, the reaction can be completed in a short time. further,
In the production method of the present invention, a so-called living polymer having polymerization activity even after the consumption of the monomer is produced, so that the block polymer can be easily produced by additionally introducing another monomer into the reaction system.

Claims (9)

[Claims] 1. A method comprising: mixing an alkoxystyrene and an anionic polymerization initiator in a hydrocarbon solvent containing a Lewis base at a temperature lower than the polymerization initiation temperature; and heating the mixture to polymerize the mixture. A method for producing an alkoxystyrene polymer, comprising: 2. The method for producing an alkoxystyrene polymer according to claim 1, wherein after the step of heating and polymerizing the mixture, another monomer is added to perform block copolymerization. 3. The method for producing an alkoxystyrene polymer according to claim 1, wherein the Lewis base is tetrahydrofuran. 4. The alkoxystyrene polymer according to claim 1, wherein the amount of the Lewis base added is 0.1 to 10% by weight based on the solvent. Production method. 5. The method for producing an alkoxystyrene polymer according to claim 1, wherein the anionic polymerization initiator is n-butyllithium. 6. The alkoxystyrene according to claim 5, wherein the anionic polymerization initiator is n-butyllithium, and the alkoxystyrene and n-butyllithium are mixed at a temperature of -55 ° C. or lower. A method for producing a polymer. 7. The alkoxystyrene polymer according to claim 1, wherein, in the step of heating and polymerizing the mixture, the polymerization is carried out at a temperature of −50 ° C. or more. Manufacturing method of coalescence. 8. The method for producing an alkoxystyrene polymer according to any one of claims 1 to 7, wherein the number average molecular weight of the obtained alkoxystyrene polymer is 10,000 or more. 9. An alkoxystyrene polymer obtained by the method for producing an alkoxystyrene polymer according to any one of claims 1 to 8.