JPH0132244B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a high purity diene polymer cyclized product. Furthermore, in detail,
The present invention relates to a method for efficiently producing, by a very economical process, a highly pure diene polymer cyclized product that has a low metal ion content and does not contain microgels and is suitable as a raw material for rubber photoresists. Cyclized products of natural rubber have long been known as so-called cyclized rubber, and have been used not only as adhesives and inks, but also as photoresists. However, cyclized natural rubber contains a lot of gel and dust, and also has a high metal ion content, so it had to be purified before it could be used as an IC resist. Polyisoprene is structurally almost the same as natural rubber, but it contains less dust and is commercially available with consistent quality, so if polyisoprene is used as a raw material, production is essentially the same as natural rubber cyclized products. Using this method, a cyclized product with few impurities can be produced, and the polyisoprene cyclized product used in currently commercially available photoresists uses commercially available polyisoprene as a raw material. In order to produce a polyisoprene cyclized product from commercially available polyisoprene, the following steps are required. (1) Mastication When polyisoprene is masticated (kneading rubber with a roll), a main chain scission reaction occurs and the molecular weight decreases, and at the same time it becomes a loose gel (a relatively large gel that usually contains 20 to 30%). The next melting process can be shortened. However, the microgels with a diameter of about 1300 Å do not disappear even after mastication and are mixed into the cyclization reaction system described below. moreover,
Since the mastication conditions determine the molecular weight and molecular weight distribution of this resist raw material, how to control these factors is the first barrier to determining the physical properties of the photoresist. (2) Dissolution and cyclization reaction Next, the masticated polyisoprene was dissolved in heated xylene, and SnCl ₄
The cyclization reaction is carried out by adding an acid catalyst such as Polyisoprene undergoes a molecular cleavage reaction and an isomerization reaction during the cyclization reaction, but the ratio of these reactions can be optimized by controlling the reaction conditions. (3) Termination, oil-water separation When a large amount of water is added to the cyclization catalyst, it is deactivated by hydrolysis, etc., so the cyclization reaction is stopped. When left to stand after mixing, the mixture separates into three layers: an emulsified oil layer, a mushy middle layer, and an aqueous layer. Since the middle layer contains a large amount of catalytic modification products such as tin hydroxide, only the top layer is taken out. (4) Purification The emulsified oil layer contains some catalytic modification products along with water, so this is removed by centrifugation and the transparent oil layer is taken out. The process of adding and mixing dilute ammonia water and centrifuging the oil layer is then repeated to reduce the metal ion content. (5) Concentration In order to facilitate the handling of the liquid in steps (2) to (4), the concentration of polyisoprene cyclized products in xylene is lower than that of the product.
It is necessary to concentrate to a predetermined concentration. However, the conventional production of polyisoprene cyclized products requires many steps, and in the refining step (4) above, it is necessary to repeat the centrifugation operation to separate the oil layer, and the overall polyisoprene The yield of isoprene cyclized product is very low. The present inventors conducted research to improve the method for producing the polyisoprene cyclized product, and found that if gel-free raw polyisoprene of the desired molecular weight could be produced, the mastication step in (1) above would be unnecessary. In addition, it has been found that by using the raw polyisoprene solution as it is in the next step, a dissolution step is not necessary, so the economic effect is immeasurable. However, when producing the above-mentioned raw material polyisoprene, if no polymerization terminator is added after the isoprene monomer has been polymerized as desired, gel formation cannot be suppressed. If an amine stabilizer, which is highly effective as a stabilizer, is added as a polymerization terminator, it will inhibit the cyclization reaction, which is a cationic reaction, and
Even if water is used as a polymerization terminator, water acts as a terminator for cationic reactions, and cyclization catalysts such as tin tetrachloride are hydrolyzed, resulting in disadvantages such as lower cyclization reaction activity. arise. The present inventors further researched this problem and arrived at the present invention. That is, in the present invention, a diene monomer is polymerized using an organometallic compound represented by the general formula RM (R represents an alkyl, aryl, or aralkyl group, and M represents a group element of the Mendeleev periodic table), and then polymerization. Without the action of a terminator, the general formula CFnH _3-o SO ₃ R′ or CFnH _3-o SO ₂ X (where R′ is hydrogen, an alkyl group, or
CFnH _3-o SO ₂ --, X is halogen, n is 1,
The present invention provides a method for producing a high-purity diene-based polymer cyclized product, which comprises cyclizing with a fluorine-containing substituted sulfonic acid compound represented by (2 or 3) and then washing the reaction system with water. According to the present invention, the manufacturing process of a diene polymer cyclized product can be simplified, no gel is generated, and the cyclization reaction can be easily achieved with high activity, and furthermore, complicated post-treatments are not required. It is possible to obtain a highly pure diene polymer cyclized product with a very low metal ion content in good yield without any additional treatment. Further, the photoresist made from the diene polymer cyclized product according to the present invention has the effect that the resist pattern hardly deforms even when subjected to heat treatment at a high temperature such as 180°C. Next, preferred embodiments of the present invention will be shown. The diene monomer that can be used in the present invention is represented by the following general formula. Here, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are the same or different and represent hydrogen, an alkyl group or an aryl group. As a suitable diene monomer,
Examples include butadiene, isoprene, 2,3-dimethylbutadiene, 2-phenylbutadiene and the like. In addition, the solvent used in the polymerization reaction and cyclization reaction is
It does not react with the polymerization catalyst represented by the general formula RM, and it is insoluble in water during the post-treatment stage, and it contains aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, and tetralin, and alicyclics such as cyclohexane and decalin. Formula hydrocarbons, aliphatic hydrocarbons such as hexane, heptane, or mixtures thereof can be suitably used. Note that fluorine-containing substituted sulfonic acid compounds or active compounds that react with cations produced in the cyclization reaction cannot be used as the solvent. As mentioned above, the polymerization catalyst represented by the general formula RM is an organometallic compound of a group element of Mendeleev's periodic table, and specifically, charge transfer complexes such as lithium naphthalene, sodium naphthalene, potassium naphthalene, n -Butyl lithium,
Examples include organometallic compounds such as sec-butyllithium, benzylpotassium, and cumylpotassium. First, a diene monomer is dissolved in a dried solvent, and then the trace amount of water in the system is measured by the Karl Fischer method or the like. After the system is brought to a predetermined polymerization reaction temperature, the amount of the polymerization catalyst represented by the general formula RM (hereinafter simply referred to as "RM") to be used is determined by the formula ( ) and added to the polymerization system. RM usage amount (ml) = 10 ³ /RM concentration (mol/) (diene monomer weight (g) diene monomer molecular weight x 1/A + reaction system weight (g) x water concentration (ppm) x 10 ^-6
/18.02)...() Here, A is a value indicating the degree of polymerization when there is no chain transfer during polymerization or when there is no association of active ends. However, in systems where chain transfer occurs or where active ends associate, it is necessary to use a value larger than the desired value. Although the polymerization reaction temperature is not particularly limited, it is preferable to carry out the reaction at room temperature or higher from the economical point of view of the reaction. Further, it is desirable that the upper limit of the polymerization reaction temperature is below the boiling point of the solvent. A particularly suitable polymerization reaction temperature is 40 to 100°C.
The monomer concentration during the polymerization reaction is not particularly limited either, but from the viewpoint of stirring the polymerization reaction system and handling of the reaction solution, it is preferably 2 to 20% by weight, particularly preferably 5 to 10% by weight. As soon as it is confirmed that the polymerization is completed by measuring the solid content concentration of the polymerization system, etc., the polymerization process can be carried out using the general formula CFnH _3-o SO ₃ R′ or CFnH _3-o SO ₂ X without using a polymerization terminator. The amount of the cyclization reaction catalyst to be used is determined using the formula () and added to the polymerization system. = 10 ₃ /Concentration of CFnH _3-o SO ₃ R′ or CFnH _3-o SO ₂ X (
Mol/) (Diene polymer (g)/diene monomer molecular weight x polymerization rate (%)/100/B+RM usage amount (mol))...(
) Here, B is a factor that controls the cyclization reaction, and when this B uses a value of 20 to 6000, the reaction can be suitably controlled. The amount of RM used (mol) in the formula means that the cyclization reaction catalyst is RM
This is the contribution of what is required to react with the polymer and stabilize the polymer terminal. It has been found that the reactants of the cyclization reaction catalyst and RM, believed to have the general formula CF ₃ SO ₃ M, do not have any adverse effect on the cyclization reaction. It is a cyclization reaction catalyst. The fluorine-containing substituted sulfonic acid compound represented by CFnH _3-o SO ₃ R′ or CFnH _3-o SO ₂ , methyl ester,
Examples of ethyl esters include acid chlorides. Among these, trifluoromethanesulfonic acid, an anhydride, methyl ester, ethyl ester, or acid chloride of this acid are preferred, and trifluoromethanesulfonic acid is particularly preferred. Regarding the concentration of the conjugated diene polymer solution during the cyclization reaction, since the cyclization reaction is a molecular reaction, it is desirable to use a solution as dilute as possible; if the concentration is too high, gelation may occur, which is undesirable. . The concentration range of this conjugated diene polymer solution varies depending on the type of conjugated diene polymer used and the cyclization reaction conditions, so it cannot be specified with certainty, but for example, in the case of 1,4-cis polybutadiene,
However, in the case of 1,4-cis polyisoprene, it is relatively difficult to gel, and gelation does not occur even at 10% by weight. Generally, it is used at a concentration of about 0.5 to 10% by weight. Note that when a conjugated diene polymer with a small molecular weight is used as the raw material for the cyclized product, the cyclized product can be obtained without gelling even in a highly concentrated polymer solution. Further, in a good solvent, the cyclization reaction proceeds smoothly and gels are difficult to form, so it is possible to maintain a high concentration of the raw material polymer, and therefore a cyclized product can be efficiently produced. The cyclization reaction is usually carried out under normal pressure at a temperature ranging from 40°C to the boiling point of the solvent, but may of course be carried out under pressure.
For example, in the case of xylene solvent, it is usually 60 to 60% under normal pressure.
Carry out at a temperature of 120°C. The progress of the cyclization reaction can be determined by measuring the rate of decrease in the viscosity of the system or the change in the refractive index of the system. When the cyclization reaction reaches the desired cyclization rate, adding 1/4 or more of the volume of water to the reaction system causes the catalyst to move to the water layer, thereby stopping the reaction. It is very easy to separate the water layer and oil layer after stirring the system, and the water layer is separated and removed.
After adding about 1/4 of the volume of water to the reaction system and stirring, the aqueous layer is separated. When the metal ion content of the oil layer is analyzed here, it is found that the metal ion content is equal to or lower than that in the method of synthesizing a polyisoprene cyclized product from commercially available polyisoprene. Therefore, a highly pure cyclized product can be obtained simply by concentrating or drying the solvent in this oil layer. As described above, according to the present invention, a highly pure cyclized product can be obtained very easily and economically advantageously. Furthermore, in order to obtain a cyclized product of a diene polymer with a different microstructure, it is necessary to use ether hydrocarbons such as diethyl ether and dioxane, or to combine these with the above-mentioned aromatic hydrocarbons, alicyclic hydrocarbons, and aliphatic hydrocarbons. This can be achieved by polymerizing the diene monomer by mixing it with a water-insoluble solvent such as , followed by a cyclization reaction, and then washing with water in the presence of the water-insoluble solvent. In addition, an anti-gelling agent can be added to the cyclized product to prevent gelation, and this anti-gelling agent may include ordinary phenol-based, sulfide-based,
Antiaging agents such as phosphite and amine are effective. Example 1 After replacing the inside of an autoclave with a capacity of 5 with nitrogen, the following operations were performed under a nitrogen stream. That is, 2280 g of dried purified toluene and 120 g of dried purified isoprene (purity 99.7%) were placed in an autoclave to form a homogeneous solution, and the water content in the system was measured and found to be 3.09 ppm. Next, after heating the system to 60°C, a concentration of 0.604 mol/n was added.
- Polymerization was started by adding 3.75 ml of a toluene solution of butyllithium, and a polyisoprene solution with a polymerization rate of 99% was obtained in 60 minutes. The viscosity of the polyisoprene was 11.5 centistokes (30°C). Since the sample was taken from inside the system, the amount of polyisoprene in the autoclave was 113.8 g. After raising the temperature inside the autoclave to 80° C., 8.68 ml of a toluene solution of trifluoromethanesulfonic acid having a concentration of 0.304 mol/mole was added to stop the polymerization and at the same time start the cyclization reaction. After 22 minutes, the viscosity in the system had decreased to 4.85 centistokes, so the contents of the system were drained into 800 ml of cold water to stop the reaction. The reaction solution separated into two layers, an aqueous layer and an oil layer, was prepared using a homomixer [M manufactured by Tokushu Kika Kogyo Co., Ltd.
After stirring for 30 minutes using a mold, the water layer and oil layer were separated, the water layer was taken out, the same amount of ion-exchanged water was added, and the same operation was repeated. After separating the aqueous layer, toluene was removed to obtain a polyisoprene cyclized product. The metal ion content of this polyisoprene cyclized product was analyzed using a flameless atomic absorption spectrophotometer (Model 170-70, manufactured by Hitachi, Ltd.). The results were as shown in Table 1. In addition, [η] of the obtained polyisoprene cyclized product
The value of 30° xylene was 0.67, and the amount of residual double bonds determined by nuclear magnetic resonance spectrum was 25%. Also,
The yield of the cyclized product based on polyisoprene was 92.4%.

【table】

[Table] According to the above table, it is understood that a cyclized product with a very low metal content can be easily obtained. Examples 2 and 3 Using the same equipment as in Example 1, polyisoprene cyclized products were produced by the same operations and under the conditions shown in Table 2.
The results are shown in Table 2.

[Table] Example 4 Using the same equipment as in Example 1, a polybutadiene cyclized product was produced under the conditions shown in Table 3 through the same operations.
The results are shown in Table 3.

【table】

[Table] Example 5 A cyclized polyisoprene product was produced under the conditions shown in Table 4 using the same equipment as in Example 1 and using trifluoromethanesulfonyl chloride instead of trifluoromethanesulfonic acid. The results are shown in Table 4.

[Table] Example 6 Using the same equipment as in Example 1, a polybutadiene cyclized product was produced under the conditions shown in Table 5 through the same operations.
The results are shown in Table 5.

【table】

[Table] Comparative Example 1 In an autoclave with a capacity of 5, commercially available polyisoprene [manufactured by Japan Synthetic Rubber Co., Ltd., JSRIR2210] 120
After the system was purged with nitrogen, 2,280 g of purified xylene was added and heated to form a homogeneous solution. After keeping the temperature inside the autoclave at 120°C, 6.0g of tin tetrachloride was added dropwise to start the cyclization reaction. After 5 hours, the temperature of the system was lowered to 50°C, and then poured into 2.5 ml of water. . After stirring for 30 minutes using a homomixer (Model M manufactured by Tokushu Kika Kogyo Co., Ltd.) and leaving it overnight, the upper layer was a cloudy xylene layer, the lower layer was an aqueous layer, and the middle layer was a mushy layer of tin hydroxide. separated. The upper layer was centrifuged to give a clear xylene solution. Furthermore, if the mixture is mixed with dilute ammonia water in a homomixer for 30 minutes and left for one day, a slightly cloudy oil layer can be recovered.
This material was centrifuged to obtain a polyisoprene cyclized product solution. The yield of the cyclized product based on polyisoprene was 43.3%, and the amount of remaining double bonds in the cyclized product was 42
%, [η] 30° xylene was 0.66. Further, the metal content per solid content of the polyisoprene cyclized product was as shown in Table 6.

【table】

Claims (1)

[Claims] 1 A diene monomer is polymerized using an organometallic compound represented by the general formula RM (R represents an alkyl, aryl, or aralkyl group, and M represents an element of Group Group of the Mendeleev periodic table), and then a polymerization terminator is applied. Without letting, the general formula CFnH _3-o
SO ₃ R′ or CFnH _3-o SO ₂ X (where R′ is hydrogen,
After cyclization with a fluorine-containing substituted sulfonic acid compound represented by an alkyl group or a fluorine-containing substituted sulfonic acid compound represented by an alkyl group or CFnH _3-o SO ₂ --, X is a halogen, and n is 1, 2 or 3, the reaction system is washed with water. A method for producing a characterized high-purity diene polymer cyclized product.