JP4308951B2 - Production method of epoxy resin - Google Patents

Description

【００３３】
表１から、実施例１〜４では、所定量のアルカリを添加した時点でエピクロルヒドリンおよび１，４−ジオキサンの除去・回収を行い、回収量に相当する量の１，４−ジオキサンを添加することにより、これらの操作を行わない比較例と比較して、得られたエポキシ樹脂の加水分解性塩素含量が大きく低減されており、全塩素含量も低減されていることがわかる。
【００３４】
【発明の効果】
以上のように本発明の製造方法によれば、エポキシ化反応において所定量のアルカリを反応系内に添加した時点で、エピハロヒドリンおよび有機溶媒を除去回収し、回収量と実質的に同量の有機溶媒を添加して残りの反応を行わせることにより、加水分解性ハロゲン含量を大きく低減させることができるという効果がある。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing an epoxy resin having a reduced hydrolyzable halogen content.
[0002]
[Prior art]
Epoxy resins have excellent properties such as electrical properties, heat resistance, adhesiveness, moisture resistance, etc. because of their cured products, including semiconductor sealing materials, electrical insulation materials, printed wiring boards, solder resists, adhesives Used in a wide range of fields such as paint.
[0003]
The epoxy resin is usually produced by a so-called epoxidation reaction in which an epihalohydrin is added to a polyhydric phenol in the presence of an alkali such as sodium hydroxide, and then the 1,2-halohydrin ether group formed is closed. As the polyhydric phenol, a novolak resin such as o-cresol novolak is often used in the case of an epoxy resin used for a sealing material in the electrical and electronic industries.
[0004]
In general, epoxy resins used in the electrical and electronic industries are required to have a low hydrolyzable halogen content. This is because hydrolyzable halogen adversely affects the reliability of so-called electronic elements, such as a decrease in electrical insulation and corrosion of lead wires.
In order to reduce the hydrolyzable halogen content in the epoxy resin, the present applicant has previously proposed that the epoxidation reaction be performed in the presence of a specific organic solvent such as dioxane (Japanese Patent Publication No. 62-34330). Publication). This method is a very effective method for obtaining an epoxy resin having a low hydrolyzable halogen content.
[0005]
[Problems to be solved by the invention]
In the method described in Japanese Patent Publication No. 62-34330, it is expected that the more the amount of the organic solvent in the reaction system, the more effective the reduction of the hydrolyzable halogen content. However, at the initial stage of the reaction, there is a problem that the reaction efficiency decreases as the content of the organic solvent increases. In order to prevent this, since the content of epihalohydrin must be increased, there is a problem that production efficiency is deteriorated.
[0006]
In the usual epoxidation reaction, the water in the system is azeotropically distilled with epihalohydrin and an organic solvent for the purpose of controlling the water in the system, and then cooled and liquefied to separate into an organic layer and an aqueous layer. The layer is returned to the reaction system and the aqueous layer is removed. Therefore, when a water-soluble organic solvent such as dioxane is used as the organic solvent, there is a problem that it becomes difficult to separate the distillate into an organic layer and an aqueous layer when the amount of the organic solvent added increases.
[0007]
An object of the present invention is to provide a method for producing an epoxy resin having a reduced hydrolyzable halogen content.
[0008]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors removed and recovered epihalohydrin when a predetermined amount of alkali was added to the reaction system, and added an organic solvent corresponding to the recovered amount. When the rest of the reaction is carried out, it is possible to obtain the same effect as the epoxidation reaction in the presence of a large amount of organic solvent without inhibiting the progress of the epoxidation reaction. As a result, the present inventors have completed the present invention.
[0009]
That is, the method for producing an epoxy resin of the present invention is a method for producing an epoxy resin by reacting a polyhydric phenol and an epihalohydrin while adding an alkali in the presence of an organic solvent. The epihalohydrin and the organic solvent are recovered at the time when 5-70% is added in a ratio, and then the amount of the organic solvent corresponding to the recovered amount is added, and the reaction is performed while adding the remaining alkali.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
As described above, the epoxy resin in the present invention is produced by reacting a polyhydric phenol and epihalohydrin while adding an alkali in the presence of an organic solvent.
Examples of the polyhydric phenol include, but are not limited to, polyhydric phenols obtained by a polycondensation reaction between phenols and a carbonyl compound or a diene compound.
[0011]
Specific examples of the polyhydric phenol include o-cresol novolak, phenol novolak, bromophenol novolak, alkylphenol novolak, polycondensate of phenols with hydroxybenzaldehyde, bisphenol A, bisphenol F, tetrabromobisphenol A, dihydroxystilbene or the like Examples thereof include alkyl derivatives, polycondensates of phenols and dicyclopentadiene, biphenols, and tetramethylbiphenol.
[0012]
The epihalohydrin is not particularly limited, and examples thereof include epichlorohydrin and epibromohydrin. Of these, epichlorohydrin is preferably used because of its availability. At this time, the epihalohydrin is preferably used in a range of 2 to 15 times the molar amount with respect to 1 mol of the phenolic hydroxyl group.
Examples of the alkali include, but are not limited to, hydroxides of alkali metals or alkaline earth metals such as sodium hydroxide, potassium hydroxide, and calcium hydroxide. The hydroxide may be used in the form of an aqueous solution having a concentration of about 20 to 55% by weight, or two or more kinds may be mixed and used. The total amount of alkali added is suitably 0.9 to 1.1 mol per mol of phenolic hydroxyl group.
[0013]
Examples of the organic solvent include ketones such as methyl ethyl ketone and methyl isobutyl ketone, hydrocarbons such as toluene and xylene, alcohols such as methanol and ethanol, cellosolves such as methyl cellosolve and ethyl cellosolve, dioxane, diethoxyethane, and the like. And ethers, dimethyl sulfoxide, dimethylformamide, and the like. Cyclic or linear ether compounds, particularly dioxane, are preferred. The amount of the organic solvent added is preferably 100 parts by weight or less, usually 10 to 100 parts by weight, based on 100 parts by weight of epihalohydrin.
[0014]
The epoxidation reaction in the present invention is a first reaction step performed by adding 5 to 70% alkali in a molar ratio with respect to the total alkali amount, a step of recovering excess epihalohydrin and an organic solvent, a step of adding an organic solvent, and It is performed in the order of the second reaction step performed by adding the remaining alkali. However, each step does not need to be independent. For example, the recovery of the epihalohydrin and the organic solvent is preferably started near the end of the first reaction step, or preferably near the end of the recovery step. Each step is partially or wholly overlapped, such as starting the organic solvent addition step, or starting the second reaction step simultaneously with the start of the organic solvent addition step or during the addition step. It may be done.
[0015]
In the first reaction step, alkali is gradually added to the solution obtained by mixing and dissolving the polyhydric phenol in the mixed solution of epihalohydrin and organic solvent as described above, and the reaction is performed under normal pressure or reduced pressure. In that case, it is preferable to carry out azeotropic dehydration for the purpose of controlling the moisture in the system.
When 5 to 70% of the total alkali amount is added in a molar ratio, the addition of the alkali is stopped, and if necessary, it is left in that state for several hours to sufficiently perform the reaction corresponding to the added alkali amount. The molar ratio (%) is determined by [added alkali amount (mol) / total alkali amount (mol)] × 100.
[0016]
In this first reaction step, it is considered that an epihalohydrin addition reaction with respect to the polyhydric phenol mainly occurs to produce a 1,2-halohydrin ether. The reaction temperature is preferably about 30 to 100 ° C., but in order to prevent an abnormal reaction from occurring during the addition reaction, the reaction temperature is preferably lower than the second reaction step described below, and usually about 30 It should be ˜60 ° C.
[0017]
In the next recovery step, excess epihalohydrin and organic solvent are removed and recovered from the reaction system. The recovery is preferably carried out by distillation under normal pressure or reduced pressure. The recovered amount of the epihalohydrin and the organic solvent is preferably 20 to 60% by weight based on the charged amount. If the recovered amount is less than 20% by weight, even if a new amount of the organic solvent is newly added, there is a possibility that an effect corresponding to that amount cannot be obtained. On the other hand, if the recovered amount exceeds 60% by weight, side reactions such as high molecular weight may occur.
[0018]
After the collection, an organic solvent in an amount corresponding to the total amount of collected epihalohydrin and organic solvent is added. At this time, when the addition amount of the organic solvent is excessively smaller than the recovered amount, not only the effect of reducing the hydrolyzable halogen content cannot be expected, but the quality may be deteriorated. On the other hand, when the amount of the organic solvent added is excessively larger than the recovered amount, it is effective for reducing the hydrolyzable halogen content, but the reaction time is extended due to the capacity limitation of the reaction kettle and the reaction concentration reduction. Productivity issues may arise. Therefore, the amount corresponding to the above-mentioned recovered amount means a range that does not cause these problems. Usually, the amount of organic solvent is the same as the recovered amount, or ± 10% by weight, preferably ± 10% by weight. What is necessary is just to add within the range of 5 weight%.
[0019]
The organic solvent to be added is preferably the same as the organic solvent recovered in the recovery step, but other organic solvents may be added as long as they are compatible with the organic solvent remaining in the reaction system and epihalohydrin. .
After the addition of the organic solvent, the epoxidation reaction is completed in the second reaction step while adding the remaining alkali. The reaction in this step is mainly a ring-closing reaction, and is a reaction in which dehydrochlorination is performed from the 1,2-halohydrin ether produced in the first reaction step to obtain a glycidyl ether of polyhydric phenol. . The reaction is carried out by gradually adding alkali to the reaction solution at a temperature of about 30 to 100 ° C., preferably about 50 to 100 ° C. under normal or reduced pressure. In that case, it is preferable to carry out azeotropic dehydration for the purpose of controlling the moisture in the system.
[0020]
After completion of the reaction, excess epihalohydrin and organic solvent are removed from the reaction solution by distillation or the like, and purified according to a conventional method to obtain an epoxy resin.
This epoxy resin has a hydrolyzable halogen content reduced as compared with an epoxy resin obtained by a conventional epoxidation reaction in which epichlorohydrin or the like is not recovered and an organic solvent corresponding to the recovered amount is not added. Therefore, it is suitable for use as a sealing material in the electronic and electrical industry fields.
[0021]
【Example】
EXAMPLES Hereinafter, although the manufacturing method of this invention is demonstrated in detail, giving an Example and a comparative example, this invention is not limited only to these Examples.
[0022]
Example 1
100 parts by weight of o-cresol novolak, 540 parts by weight of epichlorohydrin, and 173 parts by weight of 1,4-dioxane were charged into a reaction vessel and uniformly stirred and dissolved. The obtained mixed solution was maintained at 39 ° C. under a reduced pressure of 60 torr, 19 parts by weight of 48% potassium hydroxide aqueous solution was added dropwise over 1 hour, and the reaction was allowed to stand for 3.5 hours under the same conditions. During this time, the distilled condensate was received in a separating pot, the aqueous phase was removed, and the oil phase was refluxed into the system.
[0023]
Subsequently, distillation was performed at 39 to 45 ° C. under a reduced pressure of 60 torr to remove and collect epichlorohydrin and 1,4-dioxane in the reaction solution. The recovered amount was 30% by weight based on the amount charged. After the recovery, 1,4-dioxane was added in the same amount as the recovered amount, the system was adjusted to 150 torr and 60 ° C., and 56 parts by weight of 48% aqueous sodium hydroxide solution was added dropwise over 6 hours. During this time, the distilled water was removed in the same manner as described above, and the oil layer was refluxed into the system.
After completion of the reaction, the distillate was distilled off, methyl isobutyl ketone was added to the residue, and by-product sodium chloride was removed by washing with water and filtration. Finally, methyl isobutyl ketone was distilled off to obtain an o-cresol novolac epoxy resin.
[0024]
Example 2
An epoxy resin was obtained in the same manner as in Example 1 except that the recovered amounts of epichlorohydrin and 1,4-dioxane were 50% by weight based on the charged amounts.
[0025]
Example 3
An epoxy resin was obtained in the same manner as in Example 1, except that the recovery of epichlorohydrin and 1,4-dioxane was started at the time of addition of 10% of the total alkali amount in molar ratio. Details are as follows.
First, the same amounts of o-cresol novolak, epichlorohydrin and 1,4-dioxane as in Example 1 were charged into a reaction vessel, and uniformly stirred and dissolved. The obtained mixed solution was kept at 39 ° C. under a reduced pressure of 60 torr, 10 parts by weight of 48% aqueous potassium hydroxide solution was added dropwise over 0.5 hours, and the reaction was allowed to stand for 3.5 hours under the same conditions. . During this time, the distilled condensate was received in a separating pot, the aqueous phase was removed, and the oil phase was refluxed into the system.
[0026]
Then, the temperature was raised to 45 ° C. under a reduced pressure of 60 torr to remove and recover epichlorohydrin and 1,4-dioxane in the reaction solution. The recovered amount was 30% by weight based on the amount charged. After recovery, the same amount of 1,4-dioxane as the amount recovered was added, the system was adjusted to 150 torr and 60 ° C., and 9 parts by weight of 48% aqueous potassium hydroxide solution and 56 parts by weight of 48% aqueous sodium hydroxide solution were continuously added. Specifically, it was added dropwise over 6.5 hours. During this time, the distilled water was removed in the same manner as described above, and the oil layer was refluxed into the system.
After completion of the reaction, the distillate was distilled off, methyl isobutyl ketone was added to the residue, and by-product sodium chloride was removed by washing with water and filtration. Finally, methyl isobutyl ketone was distilled off to obtain an o-cresol novolac epoxy resin.
[0027]
Example 4
An epoxy resin was obtained in the same manner as in Example 1, except that the recovery of epichlorohydrin and 1,4-dioxane was changed to 60% of the total alkali amount in terms of molar ratio of alkali. Details are as follows.
First, the same amounts of o-cresol novolak, epichlorohydrin and 1,4-dioxane as in Example 1 were charged into a reaction vessel, and uniformly stirred and dissolved. The obtained mixed solution was kept at 39 ° C. under a reduced pressure of 60 torr, 19 parts by weight of 48% aqueous potassium hydroxide solution and then 29 parts by weight of 48% aqueous sodium hydroxide solution were continuously added dropwise over 3 hours. And allowed to react for 3.5 hours. During this time, the distilled condensate was received in a separating pot, the aqueous phase was removed, and the oil phase was refluxed into the system.
[0028]
Then, the temperature was raised to 45 ° C. under a reduced pressure of 60 torr to remove and recover epichlorohydrin and 1,4-dioxane in the reaction solution. The recovered amount was 30% by weight based on the amount charged. After the recovery, 1,4-dioxane was added in the same amount as the recovered amount, the system was adjusted to 150 torr and 60 ° C., and 27 parts by weight of 48% aqueous sodium hydroxide solution was added dropwise over 4 hours. During this time, the distilled water was removed in the same manner as described above, and the oil layer was refluxed into the system.
After completion of the reaction, the distillate was distilled off, methyl isobutyl ketone was added to the residue, and by-product sodium chloride was removed by washing with water and filtration. Finally, methyl isobutyl ketone was distilled off to obtain an o-cresol novolac epoxy resin.
[0029]
Comparative Example An epoxy resin was obtained in the same manner as in Example 1 except that epichlorohydrin and 1,4-dioxane were not recovered, and therefore the same amount of 1,4-dioxane was not added.
The hydrolyzable chlorine content and total chlorine content of the epoxy resins obtained in these examples and comparative examples were measured by the following methods.
[0030]
(1) Dissolve the sample with hydrolyzable chlorine content in dioxane, add 1N-potassium hydroxide in ethanol and react at room temperature for 10 minutes. The value measured by titration and divided by the sample weight was defined as the hydrolyzable chlorine content (ppm).
(2) The total chlorine content sample was dissolved in dimethyl sulfoxide, an ethanol solution of sodium hydroxide was added and kept at 50 ° C. for 40 minutes, and then titrated with a silver nitrate solution to calculate the total chlorine content (ppm).
[0031]
These measurement results are shown in Table 1 together with the recovery start amount and recovery amount of epihalohydrin and 1,4-dioxane in each Example and Comparative Example.
[0032]
[Table 1]

[0033]
From Table 1, in Examples 1-4, when a predetermined amount of alkali is added, epichlorohydrin and 1,4-dioxane are removed and recovered, and an amount of 1,4-dioxane corresponding to the recovered amount is added. Thus, it can be seen that the hydrolyzable chlorine content of the obtained epoxy resin is greatly reduced and the total chlorine content is also reduced as compared with the comparative examples in which these operations are not performed.
[0034]
【The invention's effect】
As described above, according to the production method of the present invention, when a predetermined amount of alkali is added to the reaction system in the epoxidation reaction, the epihalohydrin and the organic solvent are removed and recovered, and substantially the same amount of organic as the recovered amount is obtained. By adding a solvent to carry out the remaining reaction, the hydrolyzable halogen content can be greatly reduced.

Claims (2)

In the method of producing an epoxy resin by reacting polyphenol and epihalohydrin in the presence of dioxane while adding an alkali,
When 5 to 70% of alkali is added at a molar ratio with respect to the total amount of alkali, epihalohydrin and dioxane are recovered, then an amount of dioxane corresponding to the recovered amount is added, and the reaction is performed while adding the remaining alkali. A method for producing an epoxy resin. The recovered amount of epihalohydrin and dioxane, a manufacturing method of claim 1 Symbol placement of epoxy resin 20 to 60 wt% with respect to those charged amount.