JP2003226738A - Method for manufacturing epoxy resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an epoxy resin than can restrain gel byproduct formation, and can improve liquid separability, filterability, etc., in a byproduct salt removing step. <P>SOLUTION: An epoxy resin is manufactured by reacting a polyhydric phenol and an epihalohydrin in the presence of an alkali metal hydroxide, wherein the alkali metal hydroxide is added to a mixture of the polyhydric phenol and the epihalohydrin (1) at a temperature of 20-50°C for reaction, and then (2) at a temperature of 50-80°C that is higher than the temperature at (1), for reaction with distillation of water and the epihalohydrin off the system, not returning the distilled materials to the system. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an epoxy resin, and more particularly to a method for producing an epoxy resin suitable for use in electric and electronic industries, particularly for encapsulating electronic parts and as a laminate material. is there.

[0002]

2. Description of the Related Art Epoxy resins used in the electronic or electrical industries are required to have high purity (low hydrolyzable chlorine content, low epoxy equivalent), and various epoxy resin production methods have hitherto been used. Proposed. For example, a method in which polyhydric phenols and epihalohydrins are reacted in the presence of an alkali metal hydroxide while distilling water and epihalohydrins in the system, and the distillate is not returned to the system is also available. It has been proposed (Japanese Patent Laid-Open No. 2001-64355).

[0003]

When an epoxy resin is produced, it is usually washed with water, filtered, etc. in order to remove by-produced salts. In the case of the above method, liquid separation, filterability, etc. However, the improvement in this respect was desired. Therefore, an object of the present invention is to provide the production of an epoxy resin having improved liquid separation property, filterability and the like.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors found that the liquid separation property, filterability, etc. are insufficient because the gel produced as a by-product in the reaction. By conducting the reaction first at a relatively low temperature and then at a relatively high temperature,
The present inventors have completed the present invention by finding that the amount of by-product of gel can be suppressed and problems such as liquid separation and filterability can be solved.

That is, the present invention provides a method for producing an epoxy resin in which a polyhydric phenol and an epihalohydrin are reacted in the presence of an alkali metal hydroxide, in which a mixture of the polyhydric phenol and the epihalohydrin is added to an alkali metal. Hydroxide (1) is added in the range of 20 to 50 ° C to react, and then (2) is added in the range of 50 to 80 ° C higher than the temperature of (1) to add water and epihalohydrins in the system. The present invention provides a method for industrially excellent production of an epoxy resin, which comprises reacting while distilling and not returning the distillate to the system.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The polyphenols in the present invention are not particularly limited, and various kinds can be used. Examples thereof include condensates of phenols and carbonyl compounds such as aldehydes and ketones.

Examples of the phenols include phenol, orthocresol, paracresol, metacresol, t-butylphenol, phenylphenol, nonylphenol, 2,3-dimethylphenol, 2,5-dimethylphenol, 3,4- Dimethylphenol, 2-t-
Butyl-5-methylphenol, 2,3,5-trimethylphenol, 1-naphthol, 2-naphthol, 1-methyl-2-naphthol, 2-methyl-1-naphthol and the like can be mentioned.

Examples of aldehydes include, in addition to formaldehyde, aldehydes having an unsaturated double bond such as acrolein and crotonaldehyde, aldehydes having a plurality of aldehyde groups such as glyoxal and glutaraldehyde, benzaldehyde and hydroxybenzaldehyde. Aromatic aldehydes such as terephthalaldehyde are included. Examples of ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone.

The condensate of phenols and aldehydes is
2 for each of the above phenols and carbonyls
It is possible to use more than one type. Typical examples of the condensate include novolak resins such as cresol volac resin and phenol volac resin, bisphenols such as bisphenol A and bisphenol F, tris (hydroxyphenyl) alkanes, tetrakis (hydroxyphenyl). ) Examples include alkanes.

Examples of polyhydric phenols other than condensates of phenols and aldehydes include 4,4'-dihydroxybiphenol and 4,4'-dihydroxy-3,3 ', 5,5'-
Dihydroxybiphenols such as tetramethylbiphenyl, 4,4'-dihydroxystilbene, dihydroxystilbenes such as 4,4'-dihydroxy-3,3 ', 5,5'-tetramethylstilbene, phenols and dicyclopentadiene And an fluorene derivative, a phenol aralkyl resin, and the like. Two or more kinds of polyhydric phenols can be used if necessary.

As the other raw material, epihalohydrins, there may be mentioned epichlorohydrin, epibromohydrin and the like. Of these, epichlorohydrin is preferably used. Two or more epihalohydrins can be used if necessary. Epihalohydrins are usually 3 to 1 against the phenolic hydroxyl group of polyhydric phenols.
5 equivalents, preferably 5-10 equivalents are used.

In the present invention, a solvent may be used if necessary. Examples of such a solvent include dimethyl sulfoxide, dimethylformamide, 1,3-dimethyl-2-
Aprotic polar solvents such as imidazolidine, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, alkoxy alcohols such as methyl cellosolve, diethyl ether, ethers such as dioxane, but are not limited thereto. Absent. Of course, two or more kinds of solvents selected from these counties can also be used. It is effective to use dioxane, dimethylsulfoxide or the like when it is necessary to obtain a highly pure product. When using a solvent,
The amount used is usually 0.1 to 1 for epihalohydrins.
It is 3 times by weight, preferably 0.2 to 1 times by weight.

The alkali metal hydroxide used in the present invention includes, for example, lithium hydroxide, sodium hydroxide, potassium hydroxide and the like, and these may be used in combination of two or more kinds. The alkali metal hydroxide is usually used as a solid or 15 to 49% by weight aqueous solution. 49 weight due to volume efficiency and reaction efficiency
% Alkali metal aqueous solution, preferably used as a solid. The alkali metal hydroxide is usually used in an amount of 0.8 to 1.3 equivalents based on the phenolic hydroxyl group of the polyhydric phenol.
It is preferably 0.9 to 1.1 equivalents.

The reaction of the present invention is carried out using the above-mentioned raw materials at two reaction temperatures. The order of adding these raw materials to the reaction vessel is as follows: polyhydric phenol, epihalohydrin, The solvent used accordingly is added, and then the alkali metal hydroxide is added into this mixture.

The temperature of the first stage is in the range of 20 to 50 ° C.
Here, if the temperature is too low, the reaction is too slow, and if the temperature is too high, side reactions occur, which is not preferable. Reaction time is usually 2
~ 8 hours. Alkali metal hydroxide is 1
Use about 0 to 30%. The alkali metal hydroxide may be added all at once, but it is preferable to add it continuously.
Further, the reaction here may be carried out under normal pressure without reflux, or may be carried out under reduced pressure. In the latter case, the distilled liquid may be separated into water and then the oil layer may be returned to the inside of the system, or may be distilled out of the system as it is without returning to the inside of the system.

The temperature of the second stage is in the range of 50 to 80 ° C.
Here, if the temperature is too low, the reaction is too slow, and if the temperature is too high, side reactions occur, which is not preferable. Reaction time is usually 3
~ About 8 hours. The alkali metal hydroxide is preferably added continuously or intermittently. In addition, the reaction here is carried out under reduced pressure while distilling the epihalohydrin and water, without returning the distillate to the reaction system. During this period, it is preferable to keep the water content in the system at 0.5 to 2.0%. When the water content is low, the gel amount tends to increase, and when the water content is too high, the resin quality tends to deteriorate.

Thus, the epoxy resin is produced, but the post-treatment of the reaction solution is carried out, for example, by distilling off all or part of the epihalohydrins and, if necessary, the solvent used under reduced pressure to produce the epoxy resin and the by-product. A concentrated solution containing an alkali salt is obtained. It is desirable that the time for distilling off here is short in order to prevent deterioration of the epihalohydrins and the resin. The distillate containing epihalohydrins can be purified by a distillation column and reused, if necessary. Methyl isobutyl ketone, toluene, xylene and other organic solvents are added to the concentrated solution thus obtained to dissolve the epoxy resin, and the epoxy resin solution is removed by filtering, washing with water, etc. to remove by-product alkali salts and the like. An epoxy resin can be obtained by obtaining and then distilling off the solvent.

Further, in order to further reduce the hydrolyzable chlorine of the epoxy resin, the following method can be used. That is, a solid or aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is added to the above epoxy resin solution and treated at a temperature of about 50 to 90 ° C. for 1 to 5 hours. Here, the alkali metal hydroxide is used in an amount of 0.001 to 0.2 equivalent to the phenolic hydroxyl group of the polyhydric phenol. An epoxy resin can be obtained by neutralizing the obtained treatment liquid with phosphoric acid, carbon dioxide gas, etc., filtering, washing with water, and distilling off the solvent.

[0019]

EXAMPLES Examples will be shown below, but the present invention is not limited to these examples. The analysis and evaluation methods are as follows.

Epoxy equivalent: measured by the hydrochloric acid-dioxane method. Hydrolyzable chlorine: Epoxy resin is dissolved in dioxane,
An ethanol solution of potassium hydroxide was added, and chlorine ions desorbed when heated under reflux for 30 minutes were treated with acetic acid under acidity.
It was titrated and quantified with a silver nitrate solution, and expressed as a weight percentage of chlorine atoms in the compound. Softening point: Measured by the ball and ring method. Moisture: The reaction mass was measured by the Karl Fischer method. Filtration time: A filter paper was laid on a 4 cmφ nutche, precoated with a filter aid (Radiolite # 100, manufactured by Showa Chemical Industry Co., Ltd.), and the time required for filtration was measured at -500 Torr. Gel amount: After filtration, the filter cake was recovered, thoroughly washed with methyl isobutyl ketone and water, dried and weighed. The weight of the filter aid measured in advance was subtracted to obtain the gel amount.

Example 1 A thermometer, a dropping funnel for adding an aqueous solution of an alkali metal hydroxide, a stirring blade, and a flask equipped with a T-shaped tube and a baffle for evaporating epichlorohydrin and water from the reaction system were used. Volac (Sumitomo Chemical Co., Ltd.
Co., Ltd., softening point 105 ° C) 240g, epichlorohydrin 1665
After charging g, 583 g of dioxane and 22.5 g of water, the atmosphere was replaced with nitrogen and adjusted to 60 Torr. After heating up to 39 ℃, 49% KOH aqueous solution
46.2 g was added dropwise over 1 hour and aged for 3.5 hours. Furthermore, after adjusting to 160 Torr, the temperature was raised to 61 ° C and 49% NaOH aqueous solution was added.
127 g was dropped over 3.5 hours and aged for 0.5 hours. The distillate during this period was 959 g, and the water content in the system was 3 hours after the start of NaOH addition.
It was 1.1%.

After completion of the reaction, the unreacted epichlorohydrin and the solvent were completely removed by distillation under reduced pressure, 821 g of methyl isobutyl ketone was added to dissolve the by-product salt, and filtration was carried out. The filtration time was 45 minutes, no emulsion layer was observed after filtration, and the liquid separation property was good. The gel amount is
It was 3.5 g. Further, after removing the aqueous layer by separation, 3.2 g of a 49% caustic soda aqueous solution was added while maintaining the temperature at 80 ° C. After 2 hours, carbon dioxide was blown into the mixture to neutralize it, and the generated by-product salt was filtered off. Subsequently, the solvent was removed by distillation to obtain an epoxy resin. The epoxy equivalent of this product was 196, hydrolyzable chlorine was 400 ppm, and the softening point was 70.4 ° C.

Example 2 The procedure of Example 1 was repeated, except that 583 g of dioxane in Example 1 was replaced with 500 g of dioxane. The amount of distillate during the reaction was 980 g, the water content in the system at the third hour was 0.84%, the filtration time was 28 minutes, no emulsion layer was observed after the filtration, and the liquid separation property was good. Gel amount is 2.9 g, the epoxy equivalent of the obtained epoxy resin is 195, hydrolyzable chlorine is 410 ppm,
The softening point was 70.4 ° C.

Example 3 In Example 1, the second stage reaction pressure was changed from 160 Torr to 165.
Except for changing to Torr, the same procedure as in Example 1 was performed. The distillate amount during the reaction was 831 g, the water content in the system was 1.2% at the 3rd hour, the filtration time was 44 minutes, no emulsion layer was observed after the filtration, and the liquid separation property was good. The amount of gel is 3.2 g, the epoxy equivalent of the obtained epoxy resin is 196, hydrolyzable chlorine is 410 ppm,
The softening point was 71.2 ° C.

COMPARATIVE EXAMPLE 1 The same apparatus as in Example 1 was charged with the same amounts of orthocresol volak, epichlorohydrin, dioxane, and water, and the atmosphere was replaced with nitrogen to adjust to 160 Torr. The temperature was raised to 61 ° C., 158 g of 49% NaOH aqueous solution was added dropwise over 3.5 hours,
Aged for 0.5 hours. After that, the same procedure as in Example 1 was performed. The amount of distillate during the reaction was 971 g, and the water content in the system at the 3rd hour was 1.2%.
Met. The filtration was clogged when about 60% had been filtered, and the rest was filtered by re-precoating again. Further, about 20% of the water layer was an emulsion layer, and the liquid separation property was not so good. The gel amount is 6.3 g, the epoxy equivalent of the obtained epoxy resin is 19
8. Hydrolyzable chlorine was 430ppm and softening point was 72.1 ℃.

[0026]

EFFECTS OF THE INVENTION According to the present invention, the amount of the by-product of the gel can be suppressed, and the liquid separation property, the filterability and the like in the step of removing the by-product salt can be improved. It is advantageous as a method for producing an epoxy resin.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Nobuyuki Nakajima             Sumitomo Chemical 5-1, Soukai-cho, Niihama-shi, Ehime             Industry Co., Ltd. F term (reference) 4J036 AC02 AC03 AD07 AD08 AD10                       AF06 AF07 BA01 BA05 BA06                       BA07 BA08 BA09 JA07 JA08

Claims (7)

[Claims] 1. A method for producing an epoxy resin, which comprises reacting a polyhydric phenol with an epihalohydrin in the presence of an alkali metal hydroxide, wherein a mixture of the polyhydric phenol and the epihalohydrin is added to an alkali metal hydroxide. (1) is added in the range of 20 to 50 ° C to react, and then (2) is added in the range of 50 to 80 ° C higher than the temperature of (1) to distill water and epihalohydrins in the system. A method for producing an epoxy resin, characterized in that the distillate is not returned to the system while being reacted. 2. The method according to claim 1, wherein the alkali metal hydroxide is used in an amount of 0.8 to 1.3 equivalents based on the phenolic hydroxyl group of the polyhydric phenol. 3. The alkali metal hydroxide of (1) 20 to 50 ° C.
The method according to claim 1 or 2, wherein 10 to 30% of the total amount used is used in the range. 4. The method according to claim 1, wherein the method of adding the alkali metal hydroxide is continuous or intermittent. 5. The method according to any one of claims 1 to 4, which is carried out in the coexistence of a solvent. 6. The solvent is at least one selected from aprotic polar solvents, alkoxy alcohols and ethers.
The manufacturing method according to claim 5, which is a seed. 7. The temperature higher than the temperature of (1) in (2) 50.
The water content in the reaction system in the range of -80 degreeC is 0.5-2.0 weight%, The manufacturing method in any one of Claims 1-6 characterized by the above-mentioned.