JP2007277498A - Process for purification of epoxy resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an industrial process for purification of an epoxy resin with an organic chlorine content of 200 ppm or less in high yield. <P>SOLUTION: Dissolution of an epoxy resin with an organic chlorine content of 2,000 ppm or less in an organic solvent, addition of a solid alkali metal hydroxide adjusted to aqueous solution concentration at 55-75 wt.% at 0.05-0.5 mole to 1 kg of the resin, followed by decomposition reaction of the organic chlorine at 50-100°C gives a highly pure epoxy resin with organic chlorine content of 200 ppm or less. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for purifying an epoxy resin having a very small amount of organic chlorine, which is suitable mainly for use in the electrical and electronic industries such as electrical insulation materials including semiconductor sealing.

Epoxy resin produced by reacting polyphenols with epihalohydrin in the presence of an alkali metal hydroxide to glycidyl ether, when cured with a curing agent, becomes a cured resin having a large crosslinking density and is excellent. It shows chemical resistance, moisture resistance, and heat resistance.
Epoxy resins include inorganic chloride ions and hydrolyzable chlorinated compounds present in the molecule. Among those impurities chlorinated products, inorganic chlorine ions and some easily hydrolyzable chlorine can be easily reduced by conventional techniques, but it is very difficult to reduce other hardly hydrolyzable organic chlorines. Met. Conventionally, the amount of organic chlorine in epoxy resins used for electrical and electronic applications is typically about 600 to 1000 ppm.
However, in recent years, as electronic components have been highly integrated, miniaturization of circuits has progressed, and there has been a demand for further chlorination of the epoxy resin used.

Against this background, various manufacturing methods have been proposed to reduce the amount of organic chlorine.
For example, in Patent Document 1, an epoxy compound is characterized in that a powdery alkali metal hydroxide having an average particle size of 300 μm or less is allowed to act on an epoxy compound in an inert solvent, and then the product is extracted with a nonpolar solvent. A purification method is disclosed.
However, for example, in the case of a bisphenol F-type epoxy compound, 400 ml of toluene and 400 ml of heptane are used for extraction with respect to 100 g of resin, and the obtained purified epoxy compound has an industrial production of 61 g. When considered, it is quite inefficient. A method of dissolving an alkali metal hydroxide in alcohol has also been proposed, but it has not been sufficiently chlorinated. Thus, with the conventional purification method, it is difficult to obtain a high-purity epoxy resin having an organic chlorine content of 200 ppm or less, and even if obtained, a large amount of organic solvent is required to suppress side reactions. In addition, an extraction operation with a poor solvent is required, which is disadvantageous when industrially produced.
Japanese Examined Patent Publication No. 6-62596

  An object of this invention is to provide the refinement | purification method which can obtain the epoxy resin whose organic chlorine amount is 200 ppm or less industrially with a high yield.

In light of these circumstances, the present inventors have intensively studied for a method for purifying an epoxy resin having a low amount of organic chlorine and advantageous for industrial production. As a result, an epoxy resin having an organic chlorine amount of 2000 ppm or less has been reduced to organic solvents. A method for purifying an epoxy resin, which is dissolved in an alkali metal hydroxide having a specific concentration to perform a decomposition reaction of organic chlorine to obtain a high-purity epoxy resin having an organic chlorine content of 200 ppm or less Was found to satisfy the above-mentioned characteristics and effects, and the present invention was completed.
That is, according to the present invention, an epoxy resin having an organic chlorine content of 2000 ppm or less is dissolved in an organic solvent, and an alkali metal hydroxide having an aqueous solution concentration of 55 to 75% by weight is added to 0.1 kg of resin. The present invention relates to a method for purifying an epoxy resin, characterized by adding 05 to 0.5 mol and decomposing organic chlorine at a temperature of 50 to 100 ° C. to obtain a high-purity epoxy resin having an organic chlorine content of 200 ppm or less. It is.

  The method for purifying an epoxy resin of the present invention makes it possible to obtain a high-purity epoxy resin with a significantly reduced amount of organic chlorine in a high yield.

  The epoxy resin to be subjected to the purification reaction in the present invention is an epoxy resin having an organic chlorine content of 2000 ppm or less, and preferably an organic chlorine content of 1000 ppm or less. This is because when the amount of organic chlorine is 2000 ppm or more, the increase in resin viscosity and the loss of epoxy groups are suppressed, and the amount of organic chlorine cannot be sufficiently reduced. Specific examples of these epoxy resins include bisphenol A, bisphenol F, bisphenol E, bisphenol C, bisphenol Z, bisphenol S, bisphenol fluorene, biphenol, hydroquinone, resorcin, phenol novolac, cresol novolac, bisphenol A novolak, dihydroxynaphthalene, As an organic solvent used in a purification reaction that is a phenol aralkyl resin, terpene phenol, or the like, an epoxy resin produced from epichlorohydrin, or a molecular distillation product thereof, toluene or methyl isobutyl ketone, which is usually used in a purification reaction of an epoxy resin, is used. use. Further, if necessary, an aprotic polar solvent such as ethylene glycol dimethyl ether and diethylene glycol dimethyl ether, dimethyl sulfoxide, dioxane or the like can be used in combination. Although it is possible to obtain an epoxy resin having an organic chlorine content of 200 ppm or less without using an aprotic polar solvent, in the case of an epoxy resin containing a trifunctional or higher component, a part of the organic solvent is used. Replacing with an aprotic polar solvent is effective for preventing an increase in resin viscosity.

The organic solvent used in the purification reaction has a nonvolatile content in the range of 40 to 80% by weight. If the non-volatile content is 80% by weight, the resin viscosity increases and the epoxy group is lost. Further, if it is 40% by weight or less, the effect of reducing the amount of organic chlorine is small.
Examples of the alkali metal hydroxide used in the present invention include sodium hydroxide, potassium hydroxide, calcium hydroxide and the like, and potassium hydroxide is particularly preferable. The usage-amount of an alkali metal hydroxide is 0.05 mol-0.5 mol with respect to 1 kg of resin, Preferably it is 0.1 mol-0.3 mol. If the amount of the alkali metal hydroxide used is too large, it leads to an increase in resin viscosity and loss of epoxy groups. If the amount is too small, the effect of reducing the amount of organic chlorine is small.
The alkali metal hydroxide is used in an aqueous solution concentration range of 55% to 75%. If the aqueous solution concentration is higher than 75%, the catalytic action is too strong, leading to an increase in resin viscosity and loss of epoxy groups. If the concentration is lower than 55%, the effect of reducing the amount of organic chlorine is small. As long as the alkali metal hydroxide has a prescribed concentration, a solid alkali metal hydroxide and a necessary amount of water may be added separately in an aqueous solution state.

In the present invention, since the concentration of the alkali metal hydroxide affects the reaction rate, the moisture in the system is preferably within 0.2%.
When the recovered solvent is used and the water concentration is high, it is preferable to carry out a treatment such as dehydration before the reaction or measure the water concentration to determine the aqueous solution concentration of the alkali metal hydroxide.
The reaction temperature of the purification reaction is 50 to 100 ° C.
A temperature higher than 100 ° C. leads to an increase in resin viscosity and loss of epoxy groups. When the temperature is lower than 50 ° C., the effect of reducing the amount of organic chlorine is small. The purification reaction time is about 2 to 10 hours, preferably 3 to 6 hours. After completion of the reaction, it is diluted with a solvent such as methyl isobutyl ketone and toluene, and the by-produced salt is removed by washing with water, and phosphoric acid, sodium phosphate and oxalic acid so that the pH of the resin solution becomes 7-4. Then, neutralization was performed by adding acetic acid, carbonic acid, etc., and further washing with water was repeated, and the solvent was recovered by distillation under reduced pressure. The target amount of organic chlorine was 200 ppm or less, and the amount of hydrolyzable chlorine was 20 ppm or less. An epoxy resin is obtained.
The high-purity epoxy resin obtained by the purification reaction of the present invention has an organic chlorine content of 200 ppm or less and a hydrolyzable chlorine content of 20 ppm or less, and is suitably used as a sealing material for the electrical and electronic industries. .

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, it is not limited to these. In the following description, the epoxy equivalent, the amount of organic chlorine, and the amount of hydrolyzable salt were measured by the following methods.

The epoxy equivalent was measured by the method according to JIS K7236.
The amount of organic chlorine is obtained by dissolving an epoxy resin in butyl carbitol, adding a 1N-potassium hydroxide propylene glycol solution and performing a reflux reaction for 10 minutes in an open flame. It is a value obtained by measuring with a potentiometric titrator with a silver nitrate solution and dividing this by the sample weight.
The hydrolyzable chlorine amount is obtained by dissolving an epoxy resin in a predetermined amount of dioxane, adding an ethanol solution of 0.1 N potassium hydroxide and reacting in a water bath at 70 ° C. for 30 minutes. It is the value which measured by the potentiometric titration apparatus with the 0.01N-silver nitrate solution under acidity, and remove | divided this by the sample weight.

Example 1
YD-8125 manufactured by Tohto Kasei Co., Ltd. (BPA type liquid epoxy resin; organic chlorine content 900 ppm, in a glass flask having an internal volume of 1 liter equipped with a stirrer, a thermometer, a nitrogen gas introducing device, a dropping device, a cooling pipe and an oil / water separator. Epoxy equivalent 173 g / eq) 300 parts by weight and toluene 100 parts by weight were charged, and dissolved by heating to 40 ° C. while flowing nitrogen gas. At the same temperature, 2.52 parts by weight of solid potassium hydroxide and 1.68 parts by weight of water were added. After raising the temperature to 80 ° C., the reaction was carried out at the same temperature for 3 hours. After completion of the reaction, 450 parts by weight of toluene and 75 parts by weight of warm water were added and washed with water. Next, it neutralized with the phosphoric acid aqueous solution, and the resin solution was washed with water several times until the washing water became neutral. Further, under a reduced pressure of 5 mmHg or less, the temperature was maintained at 160 ° C. for 5 minutes, and toluene was distilled off to obtain 290 parts by weight of an epoxy resin. The epoxy equivalent of the obtained resin was 178 g / eq, the amount of organic chlorine was 120 ppm, and the amount of hydrolyzable chlorine was 6 ppm.

Example 2
YDF-8170 manufactured by Tohto Kasei Co., Ltd. (BPF type liquid epoxy resin; organic chlorine content 800 ppm, in a glass flask having an internal volume of 1 liter equipped with a stirring vessel, a thermometer, a nitrogen gas introducing device, a dropping device, a cooling pipe and an oil / water separator. 300 parts by weight of epoxy equivalent (159 g / eq), 160 parts by weight of toluene, and 40 parts by weight of dimethyl sulfoxide were charged and dissolved by heating to 40 ° C. while flowing nitrogen gas. At the same temperature, 1.68 parts by weight of solid potassium hydroxide and 1.12 parts by weight of water were added and the temperature was raised to 80 ° C., followed by reaction at the same temperature for 3 hours. After completion of the reaction, 350 parts by weight of toluene and 75 parts by weight of warm water were added and washed with water. Next, it neutralized with the phosphoric acid aqueous solution, and the resin solution was washed with water several times until the washing water became neutral. Furthermore, it hold | maintained for 5 minutes at the temperature of 160 degreeC under pressure reduction of 5 mmHg or less, and toluene and the dimethylsulfoxide were distilled off and the 285-g epoxy resin was obtained. The epoxy equivalent of the obtained resin was 163 g / eq, the amount of organic chlorine was 160 ppm, and the amount of hydrolyzable chlorine was 8 ppm.

Example 3
YDCN-500-2 (Cresol novolac type liquid solid epoxy resin manufactured by Toto Kasei Co., Ltd .; organic) to a glass flask having an internal volume of 1 liter equipped with a stirring vessel, a thermometer, a nitrogen gas introducing device, a dropping device, a cooling pipe and an oil / water separator. Chlorine amount 800 ppm, epoxy equivalent 201 g / eq) 250 parts by weight, toluene 300 parts by weight, dimethyl sulfoxide 50 parts by weight were charged and dissolved by heating to 40 ° C. while flowing nitrogen gas. At the same temperature, add 2.81 parts by weight of solid potassium hydroxide and 1.87 parts by weight of water. After raising the temperature to 80 ° C., the reaction was carried out at the same temperature for 3 hours. After completion of the reaction, 220 parts by weight of toluene and 65 parts by weight of warm water were added and washed with water. Next, it neutralized with the phosphoric acid aqueous solution, and the resin solution was washed with water several times until the washing water became neutral. Furthermore, it hold | maintained for 5 minutes at the temperature of 160 degreeC under pressure reduction of 5 mmHg or less, Toluene and dimethylsulfoxide were distilled off and 220 weight part epoxy resin was obtained. The epoxy equivalent of the obtained resin was 206 g / eq, the amount of organic chlorine was 180 ppm, and the amount of hydrolyzable chlorine was 10 ppm.

  The high-purity epoxy resin obtained by the purification reaction of the present invention has an organic chlorine content of 200 ppm or less and a hydrolyzable chlorine content of 20 ppm or less, and is suitably used as a sealing material for the electrical and electronic industries. .

Claims (5)

0.05 to 0.5 mol of solid alkali metal hydroxide prepared by dissolving an epoxy resin having an organic chlorine content of 2000 ppm or less in an organic solvent and adjusting the aqueous solution concentration to 55 to 75% by weight is added to 1 kg of the resin. A method for purifying an epoxy resin, comprising decomposing organic chlorine at a temperature of 50 to 100 ° C. to obtain a high-purity epoxy resin having an organic chlorine content of 200 ppm or less. 2. The method for purifying an epoxy resin according to claim 1, wherein the alkali metal hydroxide is potassium hydroxide. The method for purifying an epoxy resin according to claim 1 or 2, wherein the organic solvent is toluene or methyl isobutyl ketone. The method for purifying an epoxy resin according to claim 1 or 2, wherein the organic solvent is a mixed solvent of toluene and dimethyl sulfoxide. The high-purity epoxy resin is a bisphenol A-type epoxy resin or a bisphenol F-type epoxy resin, and the amount of hydrolyzable chlorine is 20 ppm or less, The epoxy resin according to any one of claims 1 to 4, Purification method.