JPH052688B2 - - Google Patents

Description

[Detailed description of the invention]

[I] Field of the Invention The present invention relates to a method for producing a high quality conjugated diene polymer cyclized product using a specific multi-component catalyst. [] Prior art and its problems It has long been known to produce cyclized products of conjugated diene polymers such as natural rubber, synthetic polyisoprene, and polybutadiene by subjecting them to a cyclization reaction. Conjugated diene-based polymeric cyclized products (hereinafter sometimes simply referred to as cyclized products) have traditionally been used as insulating materials, adhesives, paints, rubber compounds, photosensitive resins, etc., but recently, with the development of IC technology, Along with this, the importance of photosensitive resins as photoresists has increased significantly, and they have narrow molecular weight distribution,
A high quality cyclized product having a high cyclization rate is also required. Conventionally, catalysts used in the cyclization reaction include sulfuric acid, sulfonic acid, halogenated acetic acid, Brønsted acid such as perchloric acid, tin tetrachloride, titanium tetrachloride, aluminum halide, boron trifluoride,
Lewis acids such as organoaluminum compounds are known (for example, Rubber Age, Vol. 55, p. 361~
365, 1944). However, these catalysts generally have low catalytic activity and slow reaction rate, so in order to obtain a cyclized product with a high cyclization rate, a large amount of catalyst or a long reaction time is required, and the resulting cyclized product has a large molecular weight distribution. It is wide. Moreover, this reaction has poor reproducibility. In particular, when Brønsted acid is used, side reactions leading to gelation and coloring are likely to occur, and when a large amount of gel is produced as a by-product, separation of the gel causes great fatigue. As described above, in conventional cyclization reactions, it is not possible to obtain a cyclized product of a conjugated diene polymer with a high cyclization rate in a short time and with good reproducibility without side reactions that cause gelation or coloring. Ta. [] Purpose of the Invention The purpose of the present invention is to provide a method for producing a cyclized conjugated diene polymer with a high cyclization rate in a short time without side reactions that cause gelation or coloration. . In addition, in the above, the fact that there is no side reaction that causes gelation means that when the reaction solution is passed through a membrane filter with a pore size of 1 μm, substantially no gel remains on the filter. Another object is to provide a method for producing cyclized products that is reproducible in terms of cyclization rate. Another object of the present invention is to provide a method for producing a cyclized product having a narrow molecular weight distribution. Yet another object is to provide a method for producing a cyclized product suitable for example as a photoresist for IC. In addition, cyclized products suitable for photoresists include cyclization ratio, degree of cyclization, non-cyclized diene unit, and microstructure such as =CH ₂ , =CH- or = | C -CH ₃ of the cyclized part. However, in general, the cyclization rate is 40
~75%, a low ratio of weight average molecular weight ( _W ) to number average molecular weight ( _N ), and no gel is required. [] Constitution of the Invention According to the present invention, the above object is to cyclize a conjugated diene polymer in an organic solvent using a catalyst, the catalyst being selected from the group consisting of tin halide and titanium halide. Lewis acids, sulfonic acids represented by general formula (1) R-SO ₃ H (in the formula, R represents an aryl group), and general formula (2)
A Brønsted acid selected from the group consisting of halogenated acetic acids represented by HnX _3-o CCOOH (wherein, This is achieved by a manufacturing method characterized in that a molar ratio of 150:1 to 1:10 is used. [] Detailed description of the structure The conjugated diene polymer used in the present invention is a polymer of conjugated dienes such as isoprene, butadiene, pentadiene or phenylbutadiene,
Copolymers of these conjugated dienes, copolymers of these conjugated dienes with unsaturated compounds such as styrene, α-methylstyrene, ethylene, propylene, isobutylene or acrylonitrile, and also copolymers of the aforementioned polymers or copolymers. It is a modified polymer or copolymer into which a functional group such as a carboxyl group or a group having an imide structure is introduced. Specific examples include natural rubber, balata, gutta-percha, synthetic cis-1,4-polyisoprene, and synthetic trans-polyisoprene.
Examples include isoprene polymers such as 1,4-polyisoprene, polybutadiene, styrene-diene copolymers, and acrylonitrile-diene polymers. Among them, isoprene-based polymers, especially cis-1, produced using anionic catalysts,
Using 4-polyisoprene, a cyclized product with a narrow molecular weight distribution and suitable for photoresists can be obtained in a shorter time than when using conventional catalysts, without side reactions that cause gelation or coloration. preferable. The molecular weight of the conjugated diene polymer is selected from a variety of ranges depending on the intended use of the cyclized product. When the cyclized product is used, for example, in a photoresist, if the molecular weight is too small, sensitivity will decrease and film retention will be reduced. On the other hand, if the molecular weight is too large, the workability when adjusting the photoresist will deteriorate due to _the high viscosity of the cyclized product.
It is preferable that it is in the range of . In addition, if the molecular weight distribution of the conjugated diene polymer is wide, the molecular weight distribution of the generated cyclized product will also be wider, making it impossible to apply it as a cyclized product for high-resolution photoresists. good. The Lewis acid used as a component of the catalyst in the present invention must be a tin halide or a titanium halide, and Lewis acids other than the above, such as boron halides, iron halides, and aluminum halides. Alternatively, when an organoaluminum compound is used in combination with Bronsted acid, no improvement in catalyst activity is observed, the reaction rate is low, and cyclization with a high cyclization rate cannot be obtained in a short period of time. Examples of the tin halides and titanium halides include tin tetrafluoride, tin tetrachloride, tin tetrabromide, tin tetraiodide, tin difluoride, tin dichloride, tin dibromide, and tin diiodide. , titanium tetrafluoride, titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, titanium trifluoride, titanium trichloride, titanium tribromide, titanium triiodide, titanium difluoride, titanium dichloride, diodor Examples include titanium oxide or titanium diiodide. Among these, tetrahalides such as tin tetrachloride, tin tetrabromide, titanium tetrachloride, and titanium tetrabromide are preferred. In addition, Brønsted acid used as another catalyst component in the present invention has the general formula (1) R-SO ₃ H
Aromatic sulfonic acid represented by or general formula (2)
It must be a halogenated acetic acid represented by HnX ₃ -nCCOOH. Even if Brønsted acids other than those mentioned above, such as sulfuric acid, benzoic acid, or salicylic acid, are used in combination with the above-mentioned specific Lewis acid, a highly active catalyst will not be obtained, the reaction rate will not increase, and a ring with a high cyclization rate can be produced in a short period of time. No compounds are obtained. In the general formula (1), R represents an aryl group, and the group is preferably a phenyl, tolyl or naphthyl group. Further, in the general formula (2), X represents a halogen atom such as fluorine, chlorine, bromine or iodine, and n is an integer of 0 to 2.
Examples of representative aromatic sulfonic acids include benzenesulfonic acid, toluenesulfonic acid, or naphthalenesulfonic acid. Further, typical examples of halogenated acetic acids include chlorinated acetic acids such as monochloroacetic acid, dichloroacetic acid, or trichloroacetic acid, or fluorinated acetic acids such as monofluoroacetic acid, difluoroacetic acid, or trifluoroacetic acid. In general, in cyclization reactions using multi-component catalysts, there are disadvantages such as side reactions that cause gelation and coloring, significant changes in distribution due to the cyclization reaction, and slow reaction rates. . That is, for example, when polyisoprene is cyclized using a combination of tin tetrachloride and sulfuric acid, significant gelation occurs during the reaction, and a great deal of effort is required to remove the gel. In addition, when polyisoprene is cyclized in a solvent using aluminum halide and an organic halogen compound, the viscosity of the reaction solution increases, and even if the reaction is continued for a long time, the cyclization rate of the produced cyclized product is only a few percent at most. It only becomes and produces a gel. On the other hand, in the present invention, the above-mentioned disadvantages do not arise due to the multi-component combination of a specific Lewis acid and a specific Brønsted acid. Furthermore, the mixing ratio of the Lewis acid and Bronsted acid in the multi-component catalyst used in the present invention is determined by the types of catalyst components to be combined, the type of raw material conjugated diene polymer, the concentration of the conjugated diene polymer in the reaction system, Although it depends on the reaction temperature, reaction time, and the target value of the cyclization rate of the cyclized product, the molar ratio of Lewis acid and Brønsted acid is 150:1 to 1:10, especially 50:1. :1~1:
It is desirable that it be in the range of 2. If the amount of Brønsted acid mixed is too small, the reaction rate will be low and a cyclized product with a high cyclization rate cannot be obtained in a short time, and even if a cyclized product with a high cyclization rate is produced over a long period of time, the resulting cyclized product will be difficult to produce. The molecular weight distribution of the compound becomes extremely wide. On the other hand, if too much Brønsted acid is mixed, side reactions leading to gelation and coloring are likely to occur.
High quality cyclized products cannot be obtained. The total amount of the Lewis acid and Brønsted acid used in the cyclization reaction varies depending on the type of catalyst, their mixing ratio, reaction temperature, and the desired cyclization rate of the product, and cannot be determined unconditionally. The total number of moles used per 100 conjugated diene monomer units of the conjugated diene polymer (hereinafter simply referred to as catalyst amount)
It is desirable that it be in the range of 0.005 to 5, preferably 0.01 to 3. If the amount of catalyst is too large, the reaction rate will increase, which is preferable, but if the reaction is too fast, it becomes difficult to control the cyclization reaction, which is inconvenient for obtaining a cyclized product with a desired cyclization rate with good reproducibility. In addition, since the amount of catalyst residue in the cyclized product increases, it becomes impossible to use the cyclized product as a cyclized product that requires high purity, such as a photoresist. on the other hand,
If the amount of catalyst is too small, the reaction rate will be slow and it will be impractical. The multicomponent catalyst used in the present invention exhibits high activity both in a homogeneous state and in a non-uniform state in the reaction solution, but the former is preferable. The method for adding the catalyst may be either a method of sequentially adding each catalyst component to the conjugated diene polymer solution, or a method of preparing a mixed solution of the catalyst components in advance and then adding the catalyst components. The organic solvent used in the present invention may be any solvent as long as it dissolves the raw material conjugated diene polymer and the cyclized product and is inert to the polymer, its cyclized product, and the catalyst. Examples include aliphatic hydrocarbons such as hexane, heptane, octane, cyclohexane or dichloromethane, or aromatic hydrocarbons such as benzene, chlorobenzene, toluene or xylene. In addition,
In order to prevent gelation, good results may be obtained if a stabilizer such as phenols or aminos is present in the reaction system. If the concentration of the conjugated diene polymer in the cyclization reaction is too high, the viscosity of the reaction system increases, making it difficult to control the reaction, while if it is too low, a large amount of solvent is required, which is uneconomical in terms of production efficiency. Although it depends on the molecular weight of the polymer, it is generally 40% by weight or less, preferably in the range of 5 to 20% by weight. The cyclization reaction is usually carried out at a temperature of 0 to 200°C, but is preferably carried out at a temperature of 30 to 100°C in order to efficiently obtain a cyclized product without causing gelation or coloration. [] Effects of the invention In the method of the present invention, the catalyst used has high selectivity and high activity, so the reaction can be carried out under mild conditions, so side reactions that cause gelation and coloration are almost non-existent. It doesn't happen. In addition, in the method of the present invention, the cyclization rate of the produced cyclized product is reproducible, and by changing the mixing ratio of catalyst components, catalyst amount, reaction temperature, and reaction time, the cyclized product with the desired cyclization rate can be obtained. easily obtained. Additionally, during the cyclization reaction, molecular chain scission and intermolecular cross-linking of the conjugated diene polymer generally occur at the same time as the cyclization, and the molecular weight distribution of the produced cyclized product differs from the molecular weight distribution of the conjugated diene polymer. Although it becomes significantly broader, no significant change in the molecular weight distribution occurs in the method of the invention. Incidentally, in the method of the present invention, the molecular weight distribution of the conjugated diene polymer (
_W / _N ) Molecular weight distribution of the cyclized product against _R (
The ratio _W / _N ) _C is less than or equal to 3, and in the most preferred case less than or equal to 1.5. Therefore, by implementing the present invention using a raw material conjugated diene polymer having a narrow molecular weight distribution, a cyclized product having a narrow molecular weight distribution can be obtained. Furthermore, in the present invention, since the catalyst used is highly active, only a small amount is required, and in addition to being economically advantageous, the catalyst can be easily removed after the reaction, and catalyst residues in the cyclized product are eliminated. can be minimized and a highly pure cyclized product can be obtained. Therefore, the cyclized product obtained by the method of the present invention is preferably used as a cyclized product suitable for photoresists, which strongly dislike the presence of impurities such as metals. [] Examples of the invention The present invention will be specifically explained below using Examples.
The present invention is not limited to these examples in any way. In addition, in Examples and Comparative Examples, weight average molecular weight ( _W ) and molecular weight distribution ( _W /
M _N ) was measured by gel permeation chromatography, and the cyclization rate and microstructure were measured by nuclear magnetic resonance spectroscopy. Example 1 Weight average molecular weight (
_W ) 116200, molecular weight distribution _W / _N 1.46, cis-1,
Cis-1,4-polyisoprene with a 4-bond content of 71% was dissolved in xylene to prepare a 5% by weight solution.
Add tin tetrachloride and p to the solution at 40°C under a dry nitrogen atmosphere.
-Toluenesulfonic acid was added at a mixing ratio of 2.3/1 in such a proportion that the total amount of catalyst expressed in moles per 100 isoprene monomer units of polyisoprene was 0.5, and the reaction was carried out at 40°C with stirring. . When this reaction was repeated several times, the reaction solution was hardly colored during the reaction, or even if it was colored, it became colorless and transparent after washing with water, and no gel remained on the membrane filter with a pore size of 1 μm. The cyclization ratio, degree of cyclization, microstructure and molecular weight distribution of the final product were as follows.

[Table] Furthermore, as shown in Figure 1, the cyclization rate of the cyclized product increases linearly with time immediately after the start of the reaction, and then increases along a gentle curve that changes to saturation. saturation was reached. The above reaction was repeated several times, and the relationship between reaction time and cyclization rate was approximately on the curve shown in FIG. 1, confirming reproducibility. From these results, it was found that the rate of change in the cyclization rate of the produced cyclized product largely depends on the reaction rate at the initial stage of the reaction (hereinafter referred to as initial reaction rate), and is an indicator of catalytic activity. Example 2 and Comparative Example 1 In the above examples, the mixing ratio of tin tetrachloride and p-toluenesulfonic acid was varied as shown in Table 1 to increase the initial reaction rate per unit time and cyclization per unit catalyst amount. We also investigated the rate of change in the rate. In addition, the reaction solution where the cyclization rate has reached almost saturation was
The sample was passed through a membrane filter, and the presence or absence of gel remaining on the filter was examined. Furthermore, the rate of change in the molecular weight distribution due to the cyclization reaction was investigated using the ratio of the molecular weight distribution ( _W / _N ) _C of the produced cyclized product to the molecular weight distribution ( _W / _N ) _R of polyisoprene before the cyclization reaction. The results are shown in Table 1. For comparison, when tin tetrachloride and p-toluenesulfonic acid were each used alone, the cyclization reaction was performed and the initial reaction rate,
The presence or absence of produced gel and the rate of change in molecular weight distribution due to the cyclization reaction were investigated, and the results are also shown in Table 1. In cases where reactions are not reproducible, for example when tin tetrachloride is used alone, the experiment is repeated and the best results obtained are given.

【table】

[Table] Example 3 and Comparative Example 2 The procedure was the same as in Example 1 except that the mixing ratio of tin tetrachloride and p-toluenesulfonic acid, amount of catalyst, reaction temperature, and reaction time were set to the values shown in Table 2. The cyclization reaction was carried out so that the cyclization rate of the product was 50 to 65%. When the catalyst residue was removed by washing with water after the cyclization reaction, the product solution was clear and colorless like the solution before the reaction. When we investigated the cyclization rate of the cyclized product and the rate of change in molecular weight distribution due to the cyclization reaction, we found that the second
The results shown in the table were obtained. For comparison, similar experiments were conducted using tin tetrachloride and p-toluenesulfonic acid alone.

[Table] Example 4 and Comparative Example 3 Same as Example 1 except that Brønsted acid shown in Table 3 was used instead of p-toluenesulfonic acid and the reaction time was changed to the time shown in Table 3. The reaction was carried out using Table 3 shows the results of examining the coloring of the reaction solution and the cyclization rate of the cyclized product.
For comparison, the reaction was similar to that described above when sulfuric acid was used as Brønsted acid and when Brønsted acid was used alone.

[Table] However, it did not become completely transparent.
Example 5 and Comparative Example 4 The reaction was carried out in the same manner as in Example 1, except that titanium tetrachloride and dichloroacetic acid were used as catalysts.
The mixing ratio of catalyst components, amount of catalyst, reaction time, and cyclization rate of the product were as shown in Table 4. In addition,
For comparison, the reaction was carried out in the same manner as above, except that sulfuric acid was used instead of dichloroacetic acid as Brønsted acid, and in the same manner as above, except that dichloroacetic acid was used alone.

[Table] Example 6 and Comparative Example 5 The cyclization reaction was carried out in the same manner as in Example 1, except that tin tetrabromide and p-toluenesulfonic acid were used as catalysts at a molar ratio of 1:1 and a catalyst amount of 1.0. Ta. Table 5 shows the results of examining the cyclization rate of the produced cyclized product. For comparison, the reaction was carried out in the same manner as above, except that aluminum tribromide was used instead of tin tetrabromide.

【table】 [Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between the reaction time and the cyclization rate (%) of the cyclized product in the cyclization reaction of Example 1.

Claims (1)

[Scope of Claims] 1. When cyclizing a conjugated diene polymer in an organic solvent using a catalyst, the catalyst is a Lewis acid selected from the group consisting of tin halide and titanium halide, and a compound having the general formula R- SO ₃ H (in the formula,
R represents an aryl group) and an aromatic sulfonic acid represented by the general formula HnX ₃ -nCCOOH (wherein, X represents a halogen atom and n represents an integer of 0 to 2)
A cyclized conjugated diene polymer, characterized in that a Brønsted acid selected from the group consisting of halogenated acetic acids represented by the formula is used in a molar ratio of the Lewis acid to the Brønsted acid of 150:1 to 1:10. manufacturing method. 2. The Lewis acid is tin tetrachloride, the Bronsted acid is benzenesulfonic acid or toluenesulfonic acid, and the molar ratio of the tin tetrachloride to the sulfonic acid is from 50:1 to 1:2. The manufacturing method according to scope 1.