JPH06336516A - Production of epoxy resin - Google Patents

Abstract

PURPOSE:To obtain in high yield an epoxy resin which gives a cured resin excellent in heat resistance, toughness, and water resistance by reacting a given compound with an epihalohydrin in the presence of an alkali metal hydroxide. CONSTITUTION:A compound represented by formula I (wherein (n) is a positive number and R is H or Br) is reacted with an epihalohydrin (e.g., epichlorohydrin) in the presence of an alkali metal hydroxide (e.g., NaOH) at 50 deg.C or lower to obtain an epoxy resin represented by formula II (wherein each X is H or glycidyl, provided that 10-95% of the X's are glycidyl).

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 a useful epoxy resin, in which the epoxy resin obtained by the present invention is heat resistant by reacting with various curing agents.
A cured product with excellent toughness and water resistance is obtained, and it is extremely useful for a wide range of applications such as molding materials, casting materials, laminated materials, composite materials, paints, adhesives, and resists.

[0002]

2. Description of the Related Art Epoxy resins, when cured with various curing agents, generally become cured products having excellent mechanical properties, water resistance, chemical resistance, heat resistance, electrical properties, etc. It is used in a wide range of fields such as laminates, molding materials, and casting materials. Conventionally, liquid and solid bisphenol A type epoxy resins obtained by reacting bisphenol A with epichlorohydrin have been used as the most industrially used epoxy resins. In addition to liquid bisphenol A type epoxy resin, Tetrabumu bisphenol
A flame-retardant solid epoxy resin obtained by reacting the resin A is industrially used as a general-purpose epoxy resin.

However, the general-purpose epoxy resin as described above has a drawback that as the molecular weight increases, the toughness of a cured product obtained by using the epoxy resin increases, but the heat resistance decreases. Further, although a cured product obtained by mixing a polyfunctional epoxy resin such as cresol novolac epoxy resin in order to compensate for the decrease in heat resistance has high heat resistance, it has a drawback that toughness decreases and water absorption increases. . On the other hand, with the recent remarkable development of the electronic industry and the like, the heat resistance, toughness and water resistance required for electric insulating materials used for these have become more and more severe,
The advent of epoxy resins excellent in these properties has been awaited.

On the other hand, as an epoxy resin satisfying these characteristics, US Pat. No. 4,623,701 and the like report a general-purpose epoxy resin obtained by completely converting alcoholic hydroxyl groups into glycidyl ether.

[Problems to be Solved by the Invention]

However, in the production method described in the above-mentioned patent, since the reaction temperature is high and the reaction is carried out in a state of a large excess of alkali metal hydroxide, many side reactions occur and the epoxy resin having the desired structure is produced. Yield is poor. Furthermore, since the dehydrohalogenation reaction is not carried out in the presence of a hydrophobic solvent, only an epoxy resin containing a large amount of hydrolyzable chlorine can be produced. This epoxy resin containing a large amount of hydrolyzable chlorine adversely affects the properties of the cured product and particularly deteriorates the electrical properties, and is not suitable for use in electronic materials.

In view of these circumstances, the inventors of the present invention have earnestly studied for an epoxy resin whose cured product is excellent in heat resistance, toughness and water resistance, and has little hydrolyzable chlorine. It was found that the epoxy resin having a specific structure obtained by the method of the present invention imparts excellent heat resistance, toughness and water resistance to the cured product, and has completed the present invention. .

That is, the present invention is based on the formula (1) (1A)

[0007]

[Chemical 3]

(In the formula, n represents a positive number, R represents a hydrogen atom or a bromine atom, and each R may be the same or different from each other.) And an epihalohydrin are alkaline. Formula (1) characterized by reacting at a temperature of 50 ° C. or lower in the presence of a metal hydroxide

[0009]

[Chemical 4]

(In the formula, n represents a positive number. R represents a hydrogen atom or a bromine atom, and each R may be the same or different from each other. X represents a hydrogen atom or a glycidyl group. X may be the same or different from each other, but 10% or more and 95% or less of X is a glycidyl group.).

(2) The bisphenol A type epoxy resin which may be brominated and bisphenol A which may be brominated are reacted in the presence of a basic catalyst, and then,
The present invention relates to a method for producing an epoxy resin represented by the above formula (1), which comprises reacting a reaction product with epihalohydrin at a temperature of 50 ° C. or lower in the presence of an alkali metal hydroxide.

According to the production method of the present invention, an epoxy resin whose cured product is excellent in heat resistance, toughness and water resistance and has a low hydrolyzable chlorine content can be easily obtained. In the formula (1A) and the formula (1), n represents an average value, and its preferable value is 0.3 to 6, and particularly preferable value is 0.5 to 4. Also, in the formula (1), 1 of X
0 to 95% is a glycidyl group, especially 15 to 9 of X
It is preferable that 5% is a glycidyl group.

The reaction temperature for reacting the compound of formula (1A) with epihalohydrin in the presence of an alkali metal hydroxide is 50 ° C. or lower, preferably 20 to 45.
℃. The compound of formula (1A) can be synthesized by a known method, for example, the compound of formula (3)

[0014]

[Chemical 5]

(Wherein R represents the same meaning as described above) and a compound of formula (4)

[0016]

[Chemical 6]

(Wherein R represents the same meaning as described above) and a compound represented by the formula: triphenylphosphine, quaternary ammonium salt, NaO 2 in the presence or absence of a solvent.
It can be obtained by reacting with a basic catalyst such as H and imidazoles. The compound (1A)
Regarding the use ratio of each component used in obtaining the formula, the formula (4) is used for 1 equivalent of the epoxy resin represented by the formula (3).
It is preferable to use 0.2 to 0.9 equivalent of the compound represented by, and it is particularly preferable to use 0.3 to 0.8 equivalent.
The basic catalyst is preferably used in an amount of 0.005 to 0.5 part by weight, particularly preferably 0.01 to 0.3 part by weight, based on 100 parts by weight of the epoxy resin represented by the formula (3). The reaction temperature is preferably 80 to 200 ° C, particularly 10
0-170 degreeC is preferable.

The method of epoxidizing the alcoholic hydroxyl group of the compound represented by the formula (1A) is carried out by reacting the alcoholic hydroxyl group with epihalohydrin at a temperature of 50 ° C. or lower in the presence of an alkali metal hydroxide. In that case, it is particularly preferable that dimethyl sulfoxide or a quaternary ammonium salt or 1,3-dimethyl-2-imidazolidinone is allowed to coexist.

The alcoholic hydroxyl group of the compound represented by the formula (1A) is more reactive than general alcohols, and it is preferable to further add dimethylsulfoxide or dimethylsulfoxide by the presence of an alkali metal hydroxide. By using a quaternary ammonium salt or 1,3-dimethyl-2-imidazolidinone in combination, the reaction between the alcoholic hydroxyl group and the epihalohydrin can be selectively carried out and the amount of the alkali metal hydroxide can be adjusted. Thus, the alcoholic hydroxyl group of the compound represented by the formula (1A) can be epoxidized in a desired ratio.

The dimethyl sulfoxide, quaternary ammonium salt and 1,3-dimethyl-2-imidazolidinone may be used alone or in combination of two or more. The reaction may be carried out in the presence of a solvent such as alcohols, aromatic hydrocarbons, ketones, cyclic or chain ether compounds and the like.

When dimethyl sulfoxide or 1,3-dimethyl-2-imidazolidinone is used, the amount thereof used is 5% by weight to 3% based on the compound represented by the formula (1A).
00 wt% is preferred. If it is less than 5% by weight with respect to the compound represented by the formula (1A), the reaction between the hydroxyl group of the compound represented by the formula (1A) and epihalohydrin is delayed, and the reaction for a relatively long time is required. When it exceeds 300% by weight with respect to the compound represented by the formula (1A), the effect of increasing the amount is almost eliminated and the volume efficiency is deteriorated.

Examples of the quaternary ammonium salt include tetramethylammonium chloride, tetramethylammonium bromide, trimethylbenzylammonium chloride and the like. When these are used, the amount used is such that the compound represented by the formula (1A) is epoxidized. 0.3 to 50 g is preferable with respect to 1 equivalent of hydroxyl group. If the amount of the hydroxyl group to be epoxidized is less than 0.3 g based on 1 equivalent, the reaction between the hydroxyl group of the compound represented by the formula (1A) and epihalohydrin is delayed and a relatively long reaction time is required.
On the other hand, if the amount exceeds 50 g, the effect of increasing the amount is almost eliminated, but the cost is increased.

Examples of epihalohydrin include epichlorohydrin and epibromohydrin. The amount of epihalohydrin used may be 1 equivalent or more with respect to 1 equivalent of the hydroxyl group to be epoxidized in the compound represented by the formula (1A). However, if the amount exceeds 20 equivalents relative to 1 equivalent of the hydroxyl group to be epoxidized, the effect of increasing the amount will almost disappear and the volume efficiency will deteriorate, which is not preferable.

Alkali metal hydroxides include caustic soda.
Although caustic soda, caustic potash, lithium hydroxide and the like can be used, caustic soda is preferred. The amount of the alkali metal hydroxide used may be 1 to 2.0 equivalents relative to 1 equivalent of the hydroxyl group to be epoxidized in the compound represented by the formula (1A). The alkali metal hydroxide may be solid or aqueous solution. When an aqueous solution is used, the reaction can be carried out during the reaction while distilling the water in the reaction system out of the reaction system under normal pressure or reduced pressure.

The reaction temperature is 50 ° C. or lower, and if the reaction temperature exceeds 50 ° C., many side reactions occur, which is not preferable. The reaction time is usually 20 to 8 hours.

After completion of the reaction, the salt formed and the excess alkali metal hydroxide are removed by washing with water, and the excess epihalohydrin and the solvents are distilled off under reduced pressure, and further post-treatment is carried out if necessary. When the post-treatment is performed, the obtained resin is dissolved in the hydrophobic solvent. As the hydrophobic solvent, methyl isobutyl ketone, benzene, toluene, xylene and the like can be used, but methyl isobutyl ketone is preferable. These can be used alone or in a mixed system.

Then, with respect to the alcoholic hydroxyl group of the compound of the formula (1A) used as a raw material, 0.025 to 0.
A 20-fold molar amount of alkali metal hydroxide is added, and the mixture is stirred at 40 to 90 ° C. for 30 minutes to 3 hours to carry out the dehydrohalogenation reaction. At this time, the alkali metal hydroxide is 10 to
It is preferable to use a 50% aqueous solution.

After completion of the reaction, the resin solution was washed with water several times,
The desired epoxy resin can be obtained by distilling off the hydrophobic solvent under reduced pressure.

The epoxy resin obtained by the method of the present invention is
Can be cured by a conventional method with various curing agents such as polyamine-based curing agents, acid anhydride-based curing agents, phenol-based curing agents, and used in molding materials, varnishes, laminates, adhesives, composite materials, powder coatings, etc. You can do it.

[0030]

EXAMPLES Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. In the following, all parts are parts by weight unless otherwise specified.

Example 1 A round-bottomed flask equipped with a stirrer, a condenser and a thermometer was placed in a bisphenol A type epoxy resin (epoxy equivalent: 186 g with an epoxy equivalent of 186 g) as an epoxy resin represented by the formula (3) in which all R are hydrogen atoms. / Eq) 372 parts, and 113 parts of bisphenol A (phenolic hydroxyl group equivalent 114 g / eq) as a compound represented by the formula (4) are charged, heated to 150 ° C. and completely melt-mixed, and then triphenylphosphine 0 is used as a catalyst. .37 parts was added and reacted at 150 ° C. for 90 minutes. The epoxy resin (3
1) (compound of formula (1A)) has an epoxy equivalent of 480 g.
It was / eq. When the obtained epoxy resin (31) was calculated from the epoxy equivalent, n in the formula (1A) was 2.1.
It became 8. Furthermore, after dissolving the obtained epoxy resin (31) in 1628 parts of epichlorohydrin, 5.5 parts of tetramethylammonium chloride was added at 40 ° C.,
53.6 parts of 98.5% NaOH was added over 90 minutes. After the reaction was further performed at 40 ° C. for 2 hours, 126 parts of water was added and the mixture was washed twice with water. After separating the oil and water, epichlorohydrin was recovered from the oil layer by distillation under reduced pressure. To the obtained reaction product, 1320 g of methyl isobutyl ketone was added and dissolved, 7.4 g of 30% NaOH aqueous solution was added and reacted at 70 ° C. for 1 hour, then washed twice with water, separated from oily water, and then methylated from the oil layer. Isobutyl ketone was distilled off to obtain an epoxy equivalent of 29.
504 parts of an epoxy resin having 6 g / eq and hydrolyzable chlorine of 1120 ppm was obtained. When the obtained epoxy resin was calculated from the epoxy equivalent, n in the formula (1) was 2.18, 70% of X was a glycidyl group, the softening point was 64.9 ° C., and the melt viscosity at 150 ° C. was 2 It was 0.8 ps. The measurement results of the physical properties of the obtained epoxy resin are summarized in Table 1.

Comparative Example 1 The epoxy resin (31) obtained in the preliminary reaction of Example 1 was dissolved in 1628 parts of epichlorohydrin, and then 60 ° C.
Then, 5.5 parts of tetramethylammonium chloride was added thereto, and 58.1 parts of 98.5% NaOH was added over 90 minutes. After the reaction was further performed at 40 ° C. for 2 hours, 126 parts of water was added and the mixture was washed twice with water. After separation of oil and water, epichlorohydrin was distilled and recovered from the oil layer under reduced pressure to obtain an epoxy equivalent of 2
459 parts of an epoxy resin containing 99 g / eq and 2680 ppm of hydrolyzable chlorine was obtained. The obtained epoxy resin has a softening point of 65.2 ° C. and a melt viscosity at 150 ° C. of 3.0 p.
It was s. The measurement results of the physical properties of the obtained epoxy resin are summarized in Table 1.

[0033]

[Table 1] Table 1 Example 1 Comparative Example 1 Epoxy equivalent (g / eq) 296 299 Epoxidation rate (%) 70 68 Hydrolyzable chlorine (ppm) 1120 2680 Softening point (° C) 64.9 65.2 Melt viscosity (150 ° C) , Ps) 2.8 3.0 Yield (%) 95.5 87.2

Epoxidation Ratio Ratio of Epoxidized Hydroxyl Group to Hydroxyl Group in Compound of Formula (1A) Hydrolyzable Chlorine Epoxy resin is dissolved in dioxane, 1N-potassium hydroxide ethanol solution is added and refluxed. Chlorine ions desorbed when heated for 30 minutes in this state were quantified by titration with a silver nitrate solution, and the weight of chlorine atoms in the epoxy resin was determined by weight pp
expressed in m

Softening point Measured using METTLER FP80HT Melt viscosity 150 ° C., I.V. C. I Measured using a cone type viscometer Yield value obtained by dividing the weight of the obtained epoxy resin by the theoretical amount obtained when the compound of the formula (1A) is epoxidized at the above epoxidation rate.

Example 2 Example 1 except that the amount of bisphenol A was 136 parts.
Preliminary reaction is carried out in the same manner as above, and the epoxy equivalent is 629 g / e.
A q epoxy resin (32) (compound of formula (1A)) was obtained. When the obtained epoxy resin (32) was calculated from the epoxy equivalent, n in the formula (1A) was 3.23.
Further, the obtained epoxy resin (32) was dissolved in 1939 parts of epichlorohydrin, and then 6.6 parts of tetramethylammonium chloride was added at 40 ° C. to obtain 98.5% N.
63.8 parts of aOH was added over 90 minutes. 40 ° C
After reacting for 2 hours at 150 ° C., 150 parts of water was added and the mixture was washed twice with water. After separating the oil and water, epichlorohydrin was recovered from the oil layer by distillation under reduced pressure. After adding 1400 parts of methyl isobutyl ketone to the obtained reaction product and dissolving it, 30%
After adding 8.9 parts of NaOH aqueous solution and reacting at 70 ° C. for 1 hour, washing with water twice and separating oil / water, methyl isobutyl ketone was distilled off from the oil layer to obtain an epoxy equivalent of 325 g / eq,
Epoxy resin 540 with 1060 ppm hydrolyzable chlorine
I got a part. When the obtained epoxy resin was calculated from the epoxy equivalent, n in the formula (1) was 3.23, 69% of X was a glycidyl group, and the softening point was 73.5 ° C.
The melt viscosity at 150 ° C. was 7.0 ps. The measurement results of the physical properties and the like of the obtained epoxy resin are summarized in Table 2.

Comparative Example 2 The epoxy resin (32) obtained in the preliminary reaction of Example 2 was dissolved in 1939 parts of epichlorohydrin, and then 60 ° C.
Then, 6.6 parts of tetramethylammonium chloride was added thereto, and 69.1 parts of 98.5% NaOH was added over 90 minutes. After the reaction was further performed at 40 ° C. for 2 hours, 126 parts of water was added and the mixture was washed twice with water. After separation of oil and water, epichlorohydrin was distilled and recovered from the oil layer under reduced pressure to obtain an epoxy equivalent of 3
There were obtained 495 parts of an epoxy resin having 23 g / eq and 3020 ppm of hydrolyzable chlorine. The softening point of the obtained epoxy resin is 73.7 ° C, and the melt viscosity at 150 ° C is 7.4p.
It was s. The measurement results of the physical properties and the like of the obtained epoxy resin are summarized in Table 2.

[0038]

[Table 2] Table 2 Example 2 Comparative Example 2 Epoxy equivalent (g / eq) 325 323 Epoxidation rate (%) 69 71 Hydrolyzable chlorine (ppm) 1060 3020 Softening point (° C) 73.5 73.7 Melt viscosity (150 ° C) , Ps) 7.0 7.4 Yield (%) 96.1 88.0

Example 3 Preliminary reaction was carried out in the same manner as in Example 1 except that 207 parts of tetrabromobisphenol A was used in place of bisphenol A in Example 1, and the epoxy equivalent was 468 g / eq.
To obtain an epoxy resin (33) (compound of formula (1A)). The n in the formula (1A) of the obtained epoxy resin (33) was 1.44 when calculated from the epoxy equivalent.
After further dissolving 1319 parts of the obtained epoxy resin (33) epichlorohydrin, 4.5 parts of tetramethylammonium chloride was added at 40 ° C., and 98.5% Na was added.
50.6 parts of OH were added over 90 minutes. After further reacting at 40 ° C. for 2 hours, 117 parts of water was added and washed twice with water. After separating the oil and water, epichlorohydrin was recovered from the oil layer by distillation under reduced pressure. After adding 1238 parts of methyl isobutyl ketone to the obtained reaction product and dissolving it, 30% N
12.1 parts of aOH aqueous solution was added and reacted at 70 ° C. for 1 hour, then washed twice with water, oil-water separation was performed, and methyl isobutyl ketone was distilled off from the oil layer to obtain an epoxy equivalent of 320 g / e.
q, Epoxy resin 6 containing 1310 ppm of hydrolyzable chlorine
Obtained 65 parts. When the obtained epoxy resin is calculated from the epoxy equivalent, n in the formula (1) is 1.44, and X is
Of these, 78% are glycidyl groups and have a softening point of 64.0.
The melt viscosity at 300C and 150C was 3.1 ps.
The measurement results of the physical properties and the like of the obtained epoxy resin are summarized in Table 3.

Comparative Example 3 The epoxy resin (33) obtained in the preliminary reaction of Example 3 was dissolved in 1319 parts of epichlorohydrin, and then 60 ° C.
Then, 4.5 parts of tetramethylammonium chloride was added, and 54.3 parts of 98.5% NaOH was added over 90 minutes. After further reacting at 40 ° C. for 2 hours, 117 parts of water was added and washed twice with water. After separation of oil and water, epichlorohydrin was distilled and recovered from the oil layer under reduced pressure to obtain an epoxy equivalent of 3
Thus, 599 parts of an epoxy resin having 17 g / eq and 3920 ppm of hydrolyzable chlorine was obtained. The softening point of the obtained epoxy resin is 63.5 ° C, and the melt viscosity at 150 ° C is 3.0 p.
It was s. The measurement results of the physical properties and the like of the obtained epoxy resin are summarized in Table 3.

[0041]

[Table 3] Table 3 Example 3 Comparative Example 3 Epoxy equivalent (g / eq) 320 317 Epoxidation rate (%) 78 80 Hydrolyzable chlorine (ppm) 1310 3920 Softening point (° C) 64.0 63.5 Melt viscosity (150 ° C) , Ps) 3.1 3.0 Yield (%) 95.9 86.2

INDUSTRIAL APPLICABILITY The method for producing an epoxy resin of the present invention is industrially advantageous because it has a higher yield than conventional methods. Further, the epoxy resin obtained by the production method of the present invention,
The low hydrolyzable chlorine content makes it extremely useful for electrical and electronic materials.

Claims (2)

[Claims] 1. A formula (1A): (In the formula, n represents a positive number, R represents a hydrogen atom or a bromine atom, and each R may be the same or different from each other.) And epihalohydrin are combined with alkali metal water. Formula (1) characterized by reacting at a temperature of 50 ° C. or lower in the presence of an oxide (In the formula, n represents a positive number. R represents a hydrogen atom or a bromine atom, and each R may be the same or different from each other. X represents a hydrogen atom or a glycidyl group, and each X represents They may be the same or different, but 10% or more and 95% or less of X is a glycidyl group.). 2. Bisphenol A which may be brominated
-Type epoxy resin and optionally brominated bisphenol A are reacted in the presence of a basic catalyst, and then the reaction product and epihalohydrin are reacted in the presence of an alkali metal hydroxide at a temperature of 50 ° C or lower. A method for producing an epoxy resin represented by the formula (1) according to claim 1.