JPH10120758A - Epoxy resin, epoxy resin composition and its cured product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin compound of a specific epoxy resin that retains high thermal resistance and low water absorptivity, can shorten the gel time, and is useful as an insulation material for electric and electronic parts by imparting the specific epoxy resin with a specific physical property. SOLUTION: This epoxy resin is obtained by a reaction of a phenolic resin of formula I [(n) is an average of positive numbers] with an epihalohydrin without any solvent or in a solvent other than non-protonic polar solvents of form an epoxy resin of formula II (G is glycidyl) in the condition that the relationship between the value (a) (g/eq) of epoxy equivalent of the epoxy resin and the value (b) (g/eq) of hydroxyl-group equivalent of the phenolic resin is: (b+56)<a<(b+56)×1.1. Furthermore, an epoxy resin composition is obtained by compounding the above epoxy resin with a curing agent, a curing accelerator and an inorganic filler.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin and an epoxy resin composition which give a cured product having excellent water resistance, adhesiveness and curability, and a cured product thereof. It is extremely useful for a wide range of applications such as materials, casting materials, laminates, composites, paints, adhesives, resists, and the like.

[0002]

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

[0003]

However, the above-mentioned general-purpose epoxy resin has a disadvantage that as the molecular weight increases, the cured product obtained by using the same improves the mechanical strength but also increases the water absorption. .

[0004]

In view of these circumstances, the present inventors have intensively studied an epoxy resin composition which gives a cured product having excellent water resistance, adhesiveness, and curability, and as a result, a specific molecular structure was found. Having an epoxy resin composition containing an epoxy resin having an epoxy equivalent within a specific range, has been found to provide excellent water resistance, adhesiveness, and curability in the cured product, and the present invention. It has been completed.

That is, the present invention provides:

[0006]

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(Where n is an average value and represents a positive number)

Formula (1) obtained by reacting a phenol resin represented by the formula (1) with an epihalohydrin in the presence of an alkali metal hydroxide in a solvent other than a solvent or a solvent other than an aprotic polar solvent.

[0009]

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(Where n is an average value and represents a positive number;
Represents a glycidyl group. ), Wherein the epoxy equivalent value a (g / e) of the epoxy resin
q) and the value of the hydroxyl equivalent b (g /
eq) is b + 56 <a <(b + 56) × 1.1
(2) (a) an epoxy resin composition containing the epoxy resin (b) described above in (1), a curing agent, and (3) an epoxy resin composition containing a curing accelerator. (4) The epoxy resin composition according to the above (2) or (3), which contains an inorganic filler. (5) Any of the above (2), (3) or (4) A cured product obtained by curing the epoxy resin composition according to the above item 1.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

The epoxy resin represented by the formula (1) is prepared by reacting the compound represented by the formula (2) with epihalohydrin in the presence of an alkali metal hydroxide in the absence of a solvent or an aprotic polar solvent. It can be obtained by performing in a solvent.

In the compound represented by the formula (2), the value of n is an average value and represents a positive number, and is preferably 0.01 to 15.

As a method for obtaining the epoxy resin of the present invention from the compound represented by the formula (2), a known method can be adopted. For example, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is added to a dissolved mixture of the obtained phenolic resin and an excess epihalohydrin such as epichlorohydrin or epibromhydrin, or 20
The epoxy resin of the present invention can be obtained by reacting at a temperature of about 120 ° C for 1 to 10 hours.

In the reaction for obtaining the epoxy compound of the present invention, an aqueous solution of the alkali metal hydroxide may be used. In this case, the aqueous solution of the alkali metal hydroxide is continuously added to the reaction system. A method may be employed in which water and epihalohydrin are continuously flowed out under reduced pressure or normal pressure, liquids are separated, water is removed, and epihalohydrin is continuously returned into the reaction system.

A quaternary ammonium salt such as tetramethylammonium chloride, tetramethylammonium bromide or trimethylbenzylammonium chloride is added as a catalyst to a dissolved mixture of the compound represented by the formula (1) and epihalohydrin at 50 to 150 ° C. 1-5
A solid or aqueous solution of an alkali metal hydroxide is added to the halohydrin etherified compound of the compound of the formula (1) obtained by reacting for an hour, and the mixture is reacted at 20 to 120 ° C. for 1 to 10 hours to dehydrohalide (ring closed). It may be a method. In this case, the amount of the quaternary ammonium salt used is usually 1 to 10 g, preferably 2 to 8 g, per one hydroxyl group in the compound of the formula (1).

The amount of epihalohydrin used in these reactions is usually 1 to 20 mol, preferably 2 to 1 mol per equivalent of hydroxyl group of the compound represented by the above formula (2).
0 mol. The amount of the alkali metal hydroxide used is 0.8 to 1 equivalent of the hydroxyl group in the compound represented by the formula (2).
To 2.0 mol, preferably 0.9 to 1.8 mol.
Further, in order to make the reaction proceed smoothly, it is preferable to carry out the reaction by adding a solvent other than an aprotic polar solvent such as alcohols such as methanol and ethanol. The amount of the solvent to be used is usually 2 to 20% by weight, preferably 4 to 15% by weight, based on the amount of epihalohydrin.

After the reaction product of the epoxidation reaction is washed with water or without water washing, under reduced pressure at 100 to 150 ° C.
At a pressure of 10 mmHg or less, epihalohydrin, an additional solvent and the like are removed. In order to further reduce the amount of hydrolyzable halogenated epoxy compound, the recovered epoxy resin is dissolved in a solvent such as toluene, methyl isobutyl ketone, methyl ethyl ketone, and an aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide. May be further reacted to ensure ring closure. In this case, the amount of the alkali metal hydroxide used is usually 0.0 to 1 equivalent of the hydroxyl group of the compound of the formula (2) used for the epoxidation.
It is 1 to 0.3 mol, preferably 0.05 to 0.2 mol. The reaction temperature is 50 to 120 ° C, and the reaction time is usually 0.5
~ 2 hours.

After completion of the reaction, the formed salt is removed by filtration, washing with water, and the like, and the solvent such as toluene, methyl isobutyl ketone and methyl ethyl ketone is distilled off under reduced pressure under heating to obtain the epoxy resin of the present invention.

The epoxy resin of the present invention thus obtained has an epoxy equivalent a (g / eq) and a hydroxyl equivalent b (g / e) of the starting phenol resin (compound of the formula (2)).
q) is usually b + 56 <a <(b + 56) ×
1.1, preferably b + 56 <a <(b + 56) ×
1.09.

Hereinafter, the epoxy resin composition of the present invention will be described. In the epoxy resin composition described in the above (2), (3) and (4), the epoxy compound of the present invention can be used in combination with another epoxy resin. When used in combination, the proportion of the epoxy compound of the present invention in the total epoxy resin is preferably 30% by weight or more, particularly 40% by weight.
The above is preferred.

Other epoxy resins which can be used in combination with the epoxy compound of the present invention include novolak type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, biphenyl type epoxy resins, and the like. Or two or more of them may be used.

The curing agent used in the epoxy resin composition of the present invention includes, for example, amine compounds, acid anhydride compounds, amide compounds, phenol compounds and the like. Specific examples of the curing agent that can be used include diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, dicyandiamide, a polyamide resin synthesized from a dimer of linolenic acid and ethylenediamine, phthalic anhydride, and trianhydride. Melitic acid, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride,
Methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, phenol novolak, and modified products thereof, imidazole, BF ₃ -amine complex, guanidine derivative and the like. It is not limited to these. These may be used alone or in combination of two or more.

The amount of the curing agent used in the epoxy resin composition of the present invention is preferably from 0.7 to 1.2 equivalents to 1 equivalent of the epoxy group of the epoxy resin. If the amount is less than 0.7 equivalents or more than 1.2 equivalents with respect to 1 equivalent of epoxy group, curing may be incomplete and good cured physical properties may not be obtained.

When the above curing agent is used, a curing accelerator may be used in combination. Specific examples of the curing accelerator that can be used include imidazoles such as 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2- (dimethylaminomethyl) phenol,
1,8-diaza-bicyclo (5,4,0) undecene-
Tertiary amines such as 7, phosphines such as triphenylphosphine, and metal compounds such as tin octylate. The curing accelerator is used in an amount of 0.1 to 5.0 parts by weight based on 100 parts by weight of the epoxy resin as required.

The epoxy resin composition of the present invention optionally contains an inorganic filler. Specific examples of the inorganic filler that can be used include silica, alumina, and talc. The inorganic filler is used in the epoxy resin composition of the present invention in an amount of from 0 to 9;
An amount occupying 0% by weight is used. Further, to the epoxy resin composition of the present invention, various compounding agents such as a silane coupling agent, a release agent such as stearic acid, palmitic acid, zinc stearate, and calcium stearate, and a pigment can be added.

The epoxy resin composition of the present invention can be obtained by uniformly mixing the components. The epoxy resin composition of the present invention can be easily made into a cured product by a method similar to a conventionally known method. For example, the epoxy resin of the present invention and a curing agent, and if necessary, a compounding material such as a curing accelerator and a filler are sufficiently mixed as required using an extruder, a kneader, a roll, or the like until they become uniform. To obtain an epoxy resin composition, and then melt the epoxy resin composition and mold it using a casting or transfer molding machine.
The cured product of the present invention can be obtained by heating at 00 ° C. for 2 to 10 hours.

Further, the epoxy resin composition of the present invention is dissolved in a solvent such as toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, and the like, and glass fiber, carbon fiber, polyester fiber, polyamide fiber, alumina fiber, paper, etc. A prepreg obtained by impregnating a substrate and drying by heating may be subjected to hot press molding to obtain a cured product. In this case, the solvent is used in an amount of usually 10 to 70% by weight, preferably 15 to 70% by weight, and more preferably 15 to 65% by weight in the mixture of the epoxy resin composition of the present invention and the solvent.

The cured product thus obtained is excellent in mechanical strength and water resistance, and the epoxy resin composition before curing has low viscosity and good workability, so that it is required to have mechanical strength, water resistance and low viscosity. It can be used in a wide range of fields. Concretely, all kinds of electricity and materials such as sealing materials, laminates, insulating materials, etc.
Useful as an electronic material. Also, molding materials, adhesives,
It can also be used in fields such as composite materials and paints.

[0030]

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

Example 1 A nitrogen gas purge was applied to a flask equipped with a thermometer, a dropping funnel, a cooling tube, and a stirrer while nitrogen gas was purged, wherein the average value of n was 0.87, and the hydroxyl equivalent was 182
g / eq. ) Was dissolved in 740 parts of epichlorohydrin. Further, 5 parts of tetramethylammonium chloride was added, and the mixture was heated to 70 ° C., and 40 parts of flaky sodium hydroxide was added in portions over 100 minutes, and then the mixture was further reacted at 70 ° C. for 1 hour. After the completion of the reaction, the reaction solution was washed with water to remove generated salts and the like, and excess epichlorohydrin and the like were distilled off under heating and reduced pressure at 130 ° C. using a rotary evaporator, and 472 parts of methyl isobutyl ketone was added to the residue and dissolved. .

Further, the solution of methyl isobutyl ketone was heated to 70 ° C., and a 30% by weight aqueous sodium hydroxide solution 1 was added.
After adding 0 parts and reacting for 1 hour, washing with water was repeated until the pH of the washing solution became neutral. Further, the water layer is separated and removed,
Using a rotary evaporator, methyl isobutyl ketone was distilled off from the oil layer under heating and reduced pressure to obtain 227 parts of the epoxy resin (A) of the present invention represented by the above formula (1). The obtained epoxy resin has a softening point of 73.3 ° C., a melt viscosity at 150 ° C. of 2.4 poise and an epoxy equivalent of 25.
It was 4 g / eq.

Example 2 In Example 1, compound (b) was used instead of compound (a).
(Average value of n: 0.67, hydroxyl equivalent: 175 g / eq) 1
The reaction was carried out in the same manner as in Example 1 using 75 parts to obtain 222 parts of the epoxy resin (B) represented by the formula (1).
The obtained epoxy resin has a softening point of 65.3 ° C. and 150 ° C.
Was 1.0 poise and the epoxy equivalent was 248 g / eq.

Example 3 In Example 1, compound (c) was used instead of compound (a).
(Average value of n 0.37, hydroxyl equivalent 170 g / eq) 1
The reaction was carried out in the same manner as in Example 1 using 70 parts, to obtain 217 parts of the epoxy resin (C) represented by the formula (1).
The obtained epoxy resin has a softening point of 56.6 ° C. and 150 ° C.
Was 0.5 poise and the epoxy equivalent was 240 g / eq.

Using the epoxy resins (A), (B) and (C) obtained in Examples 4 to 6, as a curing agent, phenol novolak (hydroxyl equivalent 106 g / eq, softening point 83
° C) and further using a curing accelerator (triphenylphosphine) in the amount shown in the composition column of Table 1, roll kneading at 70-80 ° C for 15 minutes, cooling, pulverizing and measuring the gel time. did. The pulverized product was further tableted, and a resin molded product was prepared by a transfer molding machine, and cured at 160 ° C. for 2 hours and further at 180 ° C. for 8 hours.

The results of measuring the physical properties of the cured product thus obtained are shown in Table 1 in the column of physical properties of the cured product. The numerical values in the column of the composition of the composition in Table 1 represent parts by weight, and a and b in the physical properties of the epoxy resin are respectively the epoxy equivalent (g / eq) of the epoxy resin used and the hydroxyl equivalent of the phenol novolak (g / eq). g / eq). The measurement of physical properties and transfer molding were performed by the following methods. Gel time Heating the crushed product before tableting on a hot plate at 175 ° C. while heating was performed, and the time until gelation was measured. Transfer molding conditions Temperature: 150 ° C Molding pressure: 50 kg / cm ² Glass transition temperature (TMA) TM-7000 manufactured by Vacuum Riko Co., Ltd. Temperature rising rate 2 ° C / min. Weight increase rate after boiling in water at 100 ° C for 24 hours

[0037]

Table 1 Example 4 56 Composition of formulation Epoxy resin (A) 100 Epoxy resin (B) 100 Epoxy resin (C) 100 Phenol novolak 41.7 42.7 44.2 Physical properties of triphenylphosphine 111 Epoxy resin Epoxy equivalent (G / eq) 254 248 240 a / (b + 56) 1.076 1.074 1.062 Melt viscosity (poise / 150 ° C) 2.4 1.0 0.5 Softening point (° C) 73.3 65.3 56.6 Physical properties of pulverized product (epoxy resin composition) Gel time (second) 72 74 75 Physical properties of cured product Glass transition point (℃) 151 150 137 Water absorption (%) 0.9 0.9 0.9

As is apparent from Table 1, the epoxy resin composition of the present invention exhibited a short gel time while maintaining high heat resistance and low water absorption in the cured product.

[0039]

According to the epoxy resin composition containing the epoxy resin of the present invention, the gel time can be reduced while maintaining high heat resistance and low water absorption, and the productivity can be improved industrially. . Therefore, the epoxy resin of the present invention can be used as an insulating material for electric and electronic parts (such as a highly reliable semiconductor encapsulating material) and various composite materials such as a laminate (such as a printed wiring board) and CFRP, a paint, an adhesive, and a resist. It is very useful for a wide range of applications such as.

Claims (5)

[Claims] (1) Formula (2) Wherein n is an average value and represents a positive number. The phenolic resin represented by the formula (1) can be reacted with epihalohydrin in a solvent other than a solvent or an aprotic polar solvent in the presence of an alkali metal hydroxide. Formula (1) (Wherein, n is an average value and represents a positive number, and G represents a glycidyl group), wherein the epoxy equivalent value a (g / eq) of the epoxy resin and the raw material An epoxy resin characterized in that the relation with the hydroxyl equivalent b (g / eq) of the phenol resin is b + 56 <a <(b + 56) × 1.1. 2. An epoxy resin composition comprising (a) the epoxy resin according to claim 1 and (b) a curing agent. 3. The epoxy resin composition according to claim 2, further comprising a curing accelerator. 4. The epoxy resin composition according to claim 2, further comprising an inorganic filler. 5. A cured product obtained by curing the epoxy resin composition according to any one of claims 2, 3 and 4.