JPH0948833A - Production of phenolic resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high-purity phenolic resin by using a specific acid catalyst and also treating the reaction mixture after reaction to efficiently remove the acid catalyst and unreacted phenol. SOLUTION: First, a phenolic compound (pref. phenol or o-cresol) is reacted with a xylylene compound of the formula (R<+> and R<2> are each H, a 1-4C alkyl, etc.) (pref. xylylene glycol) in the presence of an acid catalyst, i.e., a haloalkanesulfonic acid (e.g. trifluoromethanesulfonic acid) or a haloalkanecarboxylic acid (e.g. trichloroacetic acid), <=250 deg.C in boiling point. After completing the condensation reaction, the acid catalyst as well as unreacted phenolic compound is removed from the system by distillation under reduced pressures. Furthermore, the remaining acid catalyst is neutralized with at least equivalent of a tertiary amine [pref. 1,8-diazabicyclo(5, 4, 0)undecene-7[ or its phenolic salt or an imidazole compound (pref. 2-ethyl-4-methyl-imidazole).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to various binders,
The present invention relates to a method for producing a phenolic polymer useful as a coating material, a laminated material, a molding material and the like. In particular, the present invention relates to a production method for efficiently obtaining a high-purity polymer containing few impurities, which is suitable as a raw material for an epoxy curing agent or an epoxy resin for electronic materials.

[0002]

2. Description of the Related Art Phenol formaldehyde resin is widely used for various purposes as an inexpensive heat resistant resin. Further, various resins having different structures, which have been developed for the purpose of improving the properties of ordinary phenol resins, are known. Particularly, a polycondensate obtained by a condensation reaction between an aralkyl compound such as α, α'-dimethoxy p-xylene and a phenol described in JP-B-47-15111 is well known as a phenol aralkyl resin. Widely used in various applications due to its excellent heat resistance, electrical characteristics, and humidity and chemical resistance. Furthermore, in recent years I
Along with higher density, smaller size and thinner surface mounting of C, and surface mounting, the use of C as a curing agent is expanding in the field of encapsulating materials that require moisture resistance.

Regarding the method for producing the above-mentioned phenol aralkyl resin, many methods have been disclosed in the past. The most general manufacturing method is, for example, Japanese Patent Publication No. 47-151.
Japanese Patent Publication No. 11 and Japanese Patent Publication No. Showa 48-10960 describe a method of reacting an aralkyl halide or an aralkyl alcohol derivative with an excess molar amount of phenol in the presence of a Friedel-Crafts type catalyst or diethyl sulfuric acid. As a catalyst for this reaction, p-toluenesulfonic acid (Japanese Patent Publication No. 63-238129), methanesulfonic acid (Japanese Patent Publication No. 63-238129) and the like are also disclosed.

[0004]

However, in the methods disclosed in these publications, it is difficult to completely separate the catalyst from the reaction product, and the resin obtained contains more or less acidic substances. ing. Therefore, it cannot be applied as it is to the use where impurities are particularly disliked, and it is necessary to remove the catalyst by washing with water. In addition, the residual acidic substance changes in the molecular weight distribution, increases in viscosity during the manufacturing process and use,
Causing problems such as regeneration of phenolic monomers,
It has the drawback that the quality is not stable.

For the purpose of removing an acidic substance from the product to the extent that there is substantially no problem, hydrogen chloride is continuously or intermittently added as a catalyst to complete the reaction, and then the unreacted phenol compound is recovered under reduced pressure. At the same time, a method for removing the catalyst has been reported (JP-A-5-24718).
3). However, in this method, since hydrogen chloride is corrosive, it is necessary to use glass or other non-corrosive materials for manufacturing equipment such as reactors and condensers.

Neutralization treatment is effective in order to prevent viscosity increase and molecular weight change during the production process and during use.
When neutralized with an alkali metal compound, an alkaline earth compound or the like, the salt produced is often problematic as an impurity, which is not preferable in terms of quality.

Regarding the alkaline earth compound, the present inventor previously uses a hydroxide, oxide or carbonate of barium as a neutralizing agent for the remaining sulfonic acids to insolubilize the produced sulfonate. Focusing on this, it was proposed that a resin composition having a small amount of ionic components and a reduced corrosiveness can be obtained (JP-A-3-128922).
However, when this method is used for the purpose of solving the problem of the present invention, if the neutralizing agent is in a slight excess, barium hydroxide or oxide becomes a problem as an impurity, and conversely the neutralizing agent is used. If even a small amount is insufficient, the effect of neutralization decreases. Therefore, it is necessary to strictly control the addition amount of the neutralizing agent, which is a difficult situation for industrially efficient production.

The present invention has been made in view of the above circumstances, and provides a production method for efficiently obtaining a phenol aralkyl-based resin having a small amount of impurities, high purity, and stable product quality such as viscosity. That is the purpose.

[0009]

In order to achieve the above-mentioned object, the present invention has achieved the above-mentioned problems as a result of earnestly studying the examination and removal method of catalyst species, selection of neutralizing agent species and the method thereof. As a result, a method for producing a phenol aralkyl-based resin having high purity and stable quality was found, and the present invention was achieved.

That is, the first aspect of the present invention is to provide phenols and the following general formula (1):

Embedded image (Wherein R ¹ and R ² are each independently a hydrogen atom or a C _{1 to} C ₄ alkyl group, or a C _{2 to} C ₄ acyl group), and a xylylene compound In the method for producing a phenol aralkyl resin by reacting in the presence of an acid catalyst, a halogenoalkanesulfonic acid or a halogenoalkanecarboxylic acid having a boiling point of 250 ° C. or less is used, and the acid catalyst is removed together with unreacted phenol by vacuum distillation treatment. Then, the remaining acid catalyst is neutralized with an equal amount or more of a tertiary amine or its phenol salt or imidazole, and a method for producing a phenolic resin containing substantially no acid catalyst and unreacted phenol. Is.

The present invention also includes the above vacuum distillation treatment step.
In the first step, the vacuum distillation treatment step is stopped when the amount of unreacted phenol reaches a specific range and neutralized with the above-mentioned neutralizing agent of the present invention, until the unreacted phenol disappears. A vacuum distillation treatment can also be performed. By this method, a phenolic resin having an excellent product quality can be obtained. The present invention includes a second invention which is the above-mentioned improved method.

That is, the second aspect of the present invention is to provide phenols and the following general formula (1):

Embedded image (Wherein R ¹ and R ² are each independently a hydrogen atom or a C1 to C4 alkyl group, or a C2 to C4 acyl group) are reacted with a xylylene compound in the presence of an acid catalyst. In the method for producing a phenol aralkyl resin, a halogenoalkanesulfonic acid having a boiling point of 250 ° C. or lower or a halogenoalkanecarboxylic acid is used as an acid catalyst, and the reaction product is treated by the first-stage vacuum distillation treatment step. After the unreacted phenol and the acid catalyst are removed until the reaction phenol is less than 10 wt% and 3 wt% or more, and the remaining acid catalyst is neutralized with an equal amount or more of a tertiary amine or its phenol salt or imidazole, Further, the second step vacuum distillation treatment is carried out until the unreacted phenol is exhausted, which is substantially the acid catalyst and the unreacted phenol. A method for producing a phenol aralkyl resin free. Hereinafter, the present invention will be described in detail.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Phenols used as a raw material for the phenolic resin of the present invention are various monocyclic type, polynuclear type, or condensed polycyclic type having one or more hydroxyl groups bonded to an aromatic ring. A cyclic aromatic compound can be used. Specific examples include phenol; substituted phenols such as cresol, xylenol, ethylphenol, butylphenol, phenylphenol, halogenated phenol; resorcin, catechol, dihydroxybiphenyl, tetramethyldihydroxybiphenyl, bisphenol A, bisphenol S, bisphenol F, etc. And condensed polycyclic phenols such as α-naphthol, β-naphthol, and naphthalenediol. These can be used alone or in combination of two or more. Among these phenols, phenol, o-cresol, p-cresol, p-phenylphenol, catechol, 4,4′-dihydroxybiphenyl, α- or β-naphthol are preferably used.

The xylylene compound used as a raw material for producing the phenolic resin of the present invention is represented by the following general formula (1).

Embedded image (In the formula, R ¹ and R ² are each independently a hydrogen atom, a C1-C4 alkyl group, or a C2-C4 acyl group)

Such xylylene compounds include, in addition to xylylene glycol, various xylene glycol mono or diethers and xylene glycol mono or diesters depending on the types of R ¹ and R ² . As the xylylene glycol ether, xylylene glycol dimethyl ether, xylylene glycol diethyl ether, xylylene glycol dipropyl ether,
Examples thereof include xylylene glycol dibutyl ether, xylylene glycol monomethyl ether, and xylylene glycol monoethyl ether, and examples of the xylylene glycol ester include xylylene glycol diacetic acid ester, xylylene glycol dipropionic acid ester, and xylylene glycol diethyl ester. Examples include butyric acid ester and xylylene glycol monoacetic acid ester. Of these, xylylene glycol and xylylene glycol dimethyl ether are particularly preferable. The substitution position of —CH ₂ OR in the above formula (1) may be any of ortho, meta and para, but a para position or a meta position is generally preferred, and a para-xylamine compound or a meta-xylylene compound may be used depending on the use. And a para-xylylene compound, especially a mixed xylylene compound having a meta / para ratio of 1/9 to 9/1 is preferable because a phenol resin having excellent moisture resistance and heat resistance can be obtained.

The molar ratio of the xylylene compound to the phenols is preferably 0.1 to 0.8. If this molar ratio is less than 0.1, unreacted phenols increase and the yield decreases, which is not preferable. When it exceeds 0.8, the molecular weight of the produced resin increases, the softening temperature rises, and the fluidity at the time of molding tends to be lowered, which is not preferable. A more preferable ratio is 0.2 to 0.7.

In the present invention, a halogenoalkanesulfonic acid or a halogenoalkanecarboxylic acid having a boiling point of 250 ° C. or lower is used as the acid catalyst. If the boiling point is 250 ° C or lower,
After the resin reaction, the unreacted raw material phenols can be removed at the same time when they are recovered by vacuum distillation or the like, so that it is not necessary to add troublesome steps such as washing with water. As a specific example, trifluoromethanesulfonic acid (bp 162)
C.) and trichloroacetic acid (bp 197.5 ° C.).

The amount of the acid catalyst used is not particularly limited, but it should be added in an appropriate amount within the range of 0.001 to 5% by weight with respect to the total amount of phenols and xylylene compounds depending on the type of catalyst and raw materials. Is preferred. At the time of addition, diluting the catalyst with water or an appropriate solvent and adding it is a preferable method from the viewpoint of uniform dispersion of the catalyst and fine adjustment of the effective amount of the catalyst.

The reaction between the phenols and the xylylene compound in the present invention is usually carried out in the temperature range of 100 to 180 ° C, preferably 110 to 160 ° C. The reaction time is generally 1 to 10 hours.

When the phenols and the xylylene compound are reacted, the xylylene compound may be added at the same time to proceed the reaction, or if necessary, they may be sequentially added and reacted.

This reaction is a condensation reaction and proceeds while forming water or alcohol or carboxylic acid depending on the type of xylylene compound used.

After the condensation reaction is completed, the acid catalyst in the system is distilled off together with unreacted phenols under reduced pressure, or by a suitable method such as distillation under reduced pressure while blowing an inert gas. .

After the distillation under reduced pressure, for the purpose of completely deactivating the acid catalyst slightly remaining in the polymer, neutralization is carried out using a neutralizing agent in an amount equal to or more than the residual acid amount. In the present invention, as a neutralizing agent in this case, a tertiary amine or a phenol salt thereof, or an imidazole is used.

Specific examples of the tertiary amines and their phenol salts include triethylamine, triethylenediamine, benzyldimethylamine, triethanolamine,
Examples thereof include tris (dimethylaminomethyl) phenol, tris (dimethylamino) phenol, 1,8-diazabicyclo (5,4,0) undecene-7 or a phenol salt thereof, but particularly 1,8-diazabicyclo (5,4,
0) Undecene-7 or its phenolic salt is preferred.

Examples of the imidazoles include 2-methylimidazole, 2-phenylimidazole, 2-heptadecylimidazole, 2,4-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl4-methylimidazole and the like. Particularly preferred is 2-ethyl 4-methylimidazole. These neutralizing agents may be used alone or in combination of two or more.

The amount of the neutralizing agent added needs to be equal to or more than the amount of the remaining acid. If the amount of the neutralizing agent added is insufficient with respect to the amount of the remaining acid, the thermal stability will be poor. If insufficient and subjected to heat history during use, problems such as increase in viscosity, increase in molecular weight distribution and regeneration of unreacted phenol occur, which is not preferable in terms of product quality.

When the neutralizing agent of the present invention is used, even if the added amount of the neutralizing agent exceeds the equivalent amount with respect to the residual acid amount, no problem occurs in practical use. In actual work, when the amount of acid in the resin just before neutralization was not quantified again and it was assumed that the acid catalyst remained in the total amount charged, and an equal amount of neutralizing agent was added to that amount, Although a neutralizing agent is excessively added to the above, it can be applied without any problems even in applications where impurities are extremely strictly regulated, such as an epoxy resin curing agent for semiconductor encapsulation. Therefore, it is easy to control the amount of the neutralizing agent added, which is an excellent effect of using the neutralizing agent of the present invention.

Regarding the method of adding the neutralizing agent, it is preferable to add the neutralizing agent after diluting it with water or a suitable solvent for the same purpose as when adding the acid catalyst.

A second invention is an improved method according to the first invention, wherein the removal of the catalyst and the phenols by vacuum distillation is strictly controlled, and the timing of the neutralization treatment and the steps of removing the catalyst and the phenols is further defined. .

Depending on the temperature conditions in the dephenoling step due to the difference in the raw materials such as phenols and the blending conditions such as the amount of catalyst, the thermal history in the step of removing phenols and catalyst after completion of the condensation reaction may cause Increase,
Increased viscosity and regeneration of unreacted phenols often result in unstable product quality.

It has been found that phenomena such as an increase in molecular weight distribution, an increase in viscosity, and the regeneration of unreacted phenols are caused by the cleavage and repolymerization of polymer molecules with a slight residual acid catalyst.

As a result of examining the relationship between the above-mentioned phenomenon and the operation of removing the unreacted phenol and the acid catalyst by the distillation under reduced pressure in the present invention, the phenols in the system were 3% at the final stage of the decatalysis / dephenolization process. It became clear that this phenomenon began to occur when the following became true. Therefore, as a result of further studying the improved method of the present invention with respect to this problem, when the amount of unreacted phenol reached a specific range immediately before such a phenomenon, the decatalysis / dephenol treatment step by vacuum distillation was once interrupted, It was found that the above problem can be avoided by neutralizing the slightly remaining acid at that point and then continuing the removal until the phenol is substantially not contained. As a result, it is possible to obtain a final polymerized product in which the melt viscosity and the molecular weight distribution are extremely reproducibly stable and the phenolic monomer hardly remains. The vacuum distillation varies depending on the degree of vacuum and the type of phenols selected, but when phenol is used, for example, the treatment temperature before neutralization is preferably 150 ° C. or lower. If the temperature exceeds 150 ° C., cleavage and repolymerization of polymer molecules may occur before the amount of phenol in the system reaches a specific range, which is not preferable.

In the second invention, specifically, after the condensation reaction of the phenols and the xylylene compound is completed under the same conditions as in the first invention, the vacuum distillation treatment step is divided into two steps, and the first step is performed. In the vacuum distillation treatment step, the vacuum distillation is temporarily interrupted when the content of unreacted phenols in the system reaches the range of less than 10% by weight to 3% by weight or more, and at that time, the amount of the unreacted phenols is slightly reduced by the neutralizing agent. After neutralizing and deactivating the remaining acid catalyst, the target phenolic resin is obtained by performing the removal treatment again by the second-stage vacuum distillation until substantially no unreacted phenols are contained. . The type and amount of the neutralizing agent can be the same as in the first invention.

According to the improved method of the second invention, it is possible to efficiently obtain a phenol aralkyl-based resin which has less impurities, is highly pure, and has a more stable quality such as viscosity.

The phenolic resin obtained by the method of the present invention can be widely applied to various binders, coating materials, laminating materials, molding materials, epoxy resin curing agents for semiconductor encapsulation and various resist agents. Since it is low in purity and stable in quality, it is particularly useful as a method for producing a high-quality phenolic resin suitable for an epoxy resin curing agent for semiconductor encapsulation and a resist agent for electronics.

[0036]

The present invention will be described below in detail with reference to examples. Incidentally, the method for measuring the physical properties of the products obtained in Examples and Comparative Examples,
The method of heat stability test is as follows. (1) Electric conductivity 80 g of fine powder sample was added to 80 g of pure water.
Measured at 95 ℃ x 20hrs and measured the electric conductivity of the extracted water. (2) Content of residual phenols: by gas chromatography (3) Melt viscosity: ICI melt viscometer 150 ℃ (4) Thermal stability test: After heat treatment at 160 ℃ for 5hrs, measure residual phenol content and melt viscosity in (2) and (3) above.

Example 1 In a stainless steel reaction kettle equipped with a stirrer, a condenser, and a nitrogen gas introducing tube, 59,950 parts by weight of phenol, 55,050 parts by weight of p-xylylene glycol dimethyl ether, and 6.9 parts by weight of trifluoromethanesulfonic acid. Part was diluted and added to a 1 wt% aqueous solution, and heated to 130 to 140 ° C. under a nitrogen gas stream,
While removing methanol produced by the reaction, the reaction was carried out for 3 hours until generation of a condensate was not observed.

Then, under reduced pressure of not more than 50 torr, distillation was carried out for 7 hours while heating from 110 ° C. to 140 ° C. while bubbling nitrogen to remove trifluoromethanesulfonic acid and unreacted phenol in the system. Then, 7.0 parts by weight of 1,8-diazabicyclo (5,4,0) undecene-
7 (equimolar amount (2 times equivalent amount) to the charged amount of trifluoromethanesulfonic acid) is diluted and added to a 1 wt% aqueous solution, and the mixture is stirred for 5 minutes to neutralize and remove diluted water, and then the reaction By extracting from the kettle, 69920 parts by weight of the desired product was obtained. Table 1 shows the properties of the obtained phenol resin.

Example 2 A steam introducing tube was installed in the same reaction vessel as used in Example 1, and 59950 parts by weight of phenol and 550 p-xylylene glycol dimethyl ether were added.
50 parts by weight and 6.9 parts by weight of trifluoromethanesulfonic acid were diluted and added to an aqueous solution of 1 wt% and heated to 130 to 140 ° C. under a steam flow to remove methanol produced by the reaction while removing the condensate. The reaction was carried out for 3 hours until generation was not observed. The content of unreacted phenol in the polymerization product in the kettle at the time when the condensation reaction was completed was 19.7 w.
It was t%.

After that, in order to remove unreacted phenol and trifluoromethanesulfonic acid, distillation treatment was carried out under reduced pressure of 50 torr or less while bubbling steam up to 110 ° C. for 1.5 hours (temperature is 136 ° C.).
Up). At that time, the distillation was once interrupted to carry out neutralization. Neutralization was performed by adding 7.0 parts by weight of 1,8-diazabicyclo (5,4,0) undecene-7 (equimolar amount (2 times equivalent amount) to the charged amount of trifluoromethanesulfonic acid) to a 2 wt% aqueous solution. It was carried out by diluting and adding. Immediately before neutralization, the residual phenol content in the kettle polymer was 5.4 wt% and the residual trifluoromethanesulfonic acid content by the neutralization titration method was 24.
It was ppm.

Following the neutralization treatment, vacuum distillation is restarted,
The treatment was carried out for 3 hours (the temperature was raised to 145 ° C. and then kept) to obtain 69950 parts by weight of the desired product. Table 1 shows the properties of the obtained phenol resin.

[Example 3] The amount of raw material charged was changed to phenol 6
2840 parts by weight, p-xylylene glycol dimethyl ether 52160 parts by weight as a xylylene compound, and a neutralizing agent of 1,8-diazabicyclo (5,4,0)
Production of a phenol resin and removal of the catalyst and unreacted phenol were carried out in the same manner as in Example 2 except that 5.1 parts by weight of 2-ethyl 4-methylimidazole was used in place of undecene-7. I got a part.

The amount of unreacted phenol in the product in the reaction vessel was 23.0 wt% at the end of the condensation reaction and 6.2 wt% before the neutralization treatment. Further, the content of trifluoromethanesulfonic acid before the neutralization treatment was 24 ppm. Table 1 shows the properties of the obtained phenol resin.

[Example 4] Of the charged raw materials, m-xylylene glycol dimethyl ether 413 was used instead of 55,050 parts by weight of p-xylylene glycol dimethyl ether.
Example 2 except that a mixture of 00 parts by weight and 13750 parts by weight of p-xylylene glycol dimethyl ether was used.
In the same manner as above, condensation reaction, first-stage vacuum distillation, neutralization, second
The catalyst and unreacted phenol were removed by successively performing staged vacuum distillation to obtain 69950 parts by weight of the desired product. The amount of unreacted phenol before the neutralization treatment was 6.7 wt%.
Table 1 shows the properties of the obtained phenol resin.

Example 5 A separable flask equipped with a stirrer, a condenser and a nitrogen gas inlet tube was charged with 645 parts by weight of catechol, 379 parts by weight of m-xylylene glycol dimethyl ether and 126 parts by weight of p-xylylene glycol dimethyl ether. Preparation, under nitrogen gas flow,
The temperature was raised to 130. 1.7 parts by weight of trichloroacetic acid was diluted with a 10 wt% aqueous solution, and a condensation reaction was carried out at 130 to 140 ° C. for 4 hours while adding dropwise over 2 hours. The methanol produced by the reaction was removed outside the system and concentrated with a condenser. The content of unreacted catechol in the polymerization product in the kettle at the time when the condensation reaction was completed was 20.1 wt%.

Thereafter, in order to remove the unreacted catechol and the remaining trichloroacetic acid, a distillation treatment was performed for 2.5 hours while raising the temperature from 110 ° C. while bubbling nitrogen under a reduced pressure of 20 torr or less. Up to 165 ° C). At that point, the vacuum distillation was interrupted once, and due to the difference between the weight of the distillate volatilized out of the system due to the condensation reaction and the previous vacuum treatment and cooled and trapped in the condenser, and the weight of the raw material charged, it was generated in the flask immediately before neutralization. By determining the weight of the product (820 parts by weight) and the content of trichloroacetic acid (30 ppm) in the product in the flask by the neutralization titration method, the absolute amount of trichloroacetic acid remaining in the kettle was 0.025. Parts by weight were calculated.

Then, 4-fold equivalent (0.046 parts by weight) of 1,8-diazabicyclo (5,4,0) undecene-7 was added to the remaining trichloroacetic acid as a phenol salt obtained by reacting with excess phenol. Then, neutralization was performed. The content of unreacted catechol before the neutralization treatment was 8.0 wt% with respect to the product in the kettle.

Then, following the neutralization treatment, vacuum distillation was restarted, treatment was carried out for 5 hours (the temperature was raised to 190 ° C. and kept), and a small amount of catechol remaining was removed by sublimation. 73,200 parts by weight of the desired product was obtained. The properties of the obtained phenolic resin are shown in Table 1.

Comparative Example 1 1,8-diazabicyclo (5,
4,0) Undecene-7 was not used for the neutralization treatment, and the same procedure as in Example 1 was carried out to produce a phenol resin and remove the catalyst and unreacted phenol to obtain 69910 parts by weight of a phenol resin. . Table 1 shows the properties of the obtained product.

[Comparative Example 2] A condensation reaction was carried out in the same apparatus as in Example 1 under the same raw material charge and synthesis conditions. After that, unreacted phenol and trifluoromethanesulfonic acid were removed under reduced pressure distillation conditions similar to those in Example 1, and the unreacted phenol content in the product was 0.8.
It was wt%. Attempts were made to reduce the amount of unreacted phenol in the product by further continuing the distillation under reduced pressure.
Vacuum distillation at 150 ° C / 50 torr was additionally continued.

However, the addition of the distillation treatment for 3 hours did not reduce the content of the phenol monomer, and conversely 1.
It increased to 2 wt%. After an additional treatment of 2 hours, the phenol monomer further increased to 1.6 wt% and the melt viscosity was also increased. Therefore, the treatment was terminated to obtain 68530 parts by weight of a phenol resin. The properties of this product are shown in Table 1.

[Comparative Example 3] In the apparatus used in Example 2,
The condensation reaction was carried out under the same raw material charging amount and synthesis conditions as in Example 2. Then, as in Example 2, 50 torr
110 under reduced pressure below r while bubbling steam.
The temperature was raised from ° C and the distillation treatment was performed for 1.5 hours.

At this point, the distillation was temporarily stopped, and the difference between the weight of the distillate volatilized out of the system by the condensation reaction and the pressure reduction treatment up to that time and cooled and trapped by the condenser and the weight of the raw material charged, the kettle just before neutralization was determined. Calculate the weight of internal products (758
40 parts by weight), and the trifluoromethanesulfonic acid content (27 ppm) in the product in the kettle was determined by the neutralization titration method to give an absolute amount of trifluoromethanesulfonic acid remaining in the kettle of 2.05 parts by weight. Was calculated.

Next, barium hydroxide octahydrate was diluted with a 2 wt% aqueous solution to neutralize it. The amount of barium hydroxide added is 0 relative to the calculated value of residual trifluoromethanesulfonic acid in consideration of the accuracy of quantitative determination of the amount of residual trifluoromethanesulfonic acid and the adverse effect of residual barium hydroxide due to excessive blending of barium hydroxide. It was set to 0.85 equivalent (4.31 parts by weight).

Then, following the neutralization treatment, vacuum distillation was restarted and treatment was carried out for 3 hours (the temperature was raised to 145 ° C. and kept) to obtain 69940 parts by weight of a product. Table 1 shows the properties of the obtained phenol resin.

[0056]

[Table 1]

As is clear from the results shown in Table 1, Example 1
In all of Nos. 5 to 5, high-purity phenolic resins with less residual phenols were obtained, and there was no change in product quality due to heat history. On the contrary, the heat stability is poor in any of the comparative examples using no neutralizing agent or using a neutralizing agent other than the present invention. Further, as is clear from Comparative Example 2, the residual phenol amount rather increased and the melt viscosity also tended to increase even after long-time vacuum distillation.

[Comparative Example 4] In the apparatus used in Example 2,
The condensation reaction was carried out under the same raw material charging amount and synthesis conditions as in Example 2. Then, as in Example 2, 50 torr
110 under reduced pressure below r while bubbling steam.
The temperature was raised from ° C and the distillation treatment was performed for 1.5 hours.

At this point, the distillation was once stopped, and barium hydroxide octahydrate was neutralized with a neutralizing agent. The addition amount of barium hydroxide was equal to that of trifluoromethanesulfonic acid as in Example 2 (14 times equivalent).
5 parts by weight was diluted with a 2 wt% aqueous solution and added. When the residual phenol content and residual trifluoromethanesulfonic acid content of the kettle polymer immediately before neutralization were confirmed after the fact, they were 5.9 wt% and 21 ppm, respectively.

Following the neutralization treatment, vacuum distillation was carried out again under the same conditions as in Example 2 to obtain 69940 parts by weight of a phenol resin. This phenol resin was made into a fine powder, and 8 g was extracted in 80 g of pure water under the condition of 95 ° C. × 20 hrs. According to ICP analysis of the extracted water, Ba of 64 ppm on resin basis
Ions were extracted. This means that the hydroxide of barium and the like remains as impurities and is not of high quality.

[Example 6 and Comparative Example 5] The reproducibility of the physical properties of the product (variation in the physical properties) when Example 2 and Comparative Example 1 were repeatedly manufactured was examined. Table 2 shows the results.

[0062]

[Table 2]

[Example 7, Comparative Example 6] Using a 1.5 m ³ reaction kettle, the reaction was carried out on a 10-fold scale of Example 2 and Comparative Example 1, and the reproducibility of the resin physical properties when the scale was changed was examined. . The results are shown in Table 3 together with the results of Example 2 and Comparative Example 1.

[0064]

[Table 3] Effects on properties during scale-up

In Examples 6 and 7, reproducibility by repeating or scaling up is good, but in Comparative Examples 5 and 6, good reproducibility is not obtained.

[0066]

EFFECTS OF THE INVENTION To efficiently remove acidic ionic substances such as catalysts and unreacted phenols by carrying out resinification with a specific catalyst and performing vacuum distillation treatment and neutralization treatment with a specific neutralizing agent. It is possible to obtain a high-purity phenolic resin with few impurities that requires high performance.

Claims (7)

[Claims] 1. Phenols and the following general formula (1): (Wherein R ¹ and R ² are each independently a hydrogen atom or a C _{1 to} C ₄ alkyl group, or a C _{2 to} C ₄ acyl group), and a xylylene compound In the method for producing a phenol aralkyl resin by reacting in the presence of an acid catalyst, a halogenoalkanesulfonic acid or a halogenoalkanecarboxylic acid having a boiling point of 250 ° C. or less is used, and the acid catalyst is removed together with unreacted phenol by vacuum distillation treatment. Then, the remaining acid catalyst is neutralized with an equal amount or more of a tertiary amine or its phenol salt or imidazole, and a method for producing a phenolic resin containing substantially no acid catalyst and unreacted phenol. . 2. The method for producing a phenolic resin according to claim 1, wherein the tertiary amine or its phenol salt is 1,8-diazabicyclo (5,4,0) undecene-7, or its phenol salt. 3. The method for producing a phenolic resin according to claim 1, wherein the imidazole compound is 2-ethyl 4-methylimidazole. 4. Phenols and the following general formula (1): (Wherein R ¹ and R ² are each independently a hydrogen atom or a C1 to C4 alkyl group, or a C2 to C4 acyl group) are reacted with a xylylene compound in the presence of an acid catalyst. In the method for producing a phenol aralkyl resin, a halogenoalkanesulfonic acid or a halogenoalkanecarboxylic acid having a boiling point of 250 ° C. or lower is used as an acid catalyst, and the reaction product is subjected to a first-stage vacuum distillation treatment step to obtain an unreacted phenol. After the unreacted phenols and the acid catalyst are removed until the amount of the compounds is less than 10 wt% and 3 wt% or more, and the remaining acid catalyst is neutralized with an equal amount or more of the tertiary amine or its phenol salt or imidazole, Further, the second step vacuum distillation treatment is carried out until the unreacted phenols are exhausted. Method for producing a phenol aralkyl resin containing no. 5. The method for producing a phenolic resin according to claim 4, wherein the tertiary amine or its phenol salt is 1,8-diazabicyclo (5,4,0) undecene-7 or its phenol salt. 6. The method for producing a phenolic resin according to claim 4, wherein the imidazole is 2-ethyl-4-methylimidazole. 7. The xylylene compound has a meta / para ratio of 1 /
The method for producing a phenolic resin according to claim 1, which is a mixture of a 9-9 / 1 meta-xylylene compound and a para-xylylene compound.