JPH1036485A - Epoxy resin, epoxy resin composition and cured product thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin which has a low viscosity and can give a cured product having excellent mechanical strengths by glycidyletherifying the alcoholic hydroxyl groups of a compound having a structure derived from the addition reaction of each hydroxyl group of bisphenolfluore with an ethylene oxide chain. SOLUTION: The alcoholic hydroxyl groups of a compound having a structure derived by the addition reaction of each hydroxyl group of bisphenolfluorene with an ethylene oxide are glycidyl-etherified to obtain a liquid epoxy resin represented by the formula (wherein n is 0-20; R is H, a halogen or a 1-4C alkyl; and G is glycidyl). This epoxy resin is mixed with a curing agent and optionally a cure accelerator or/and an inorganic filler to obtain an epoxy resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin, an epoxy resin composition and a cured product thereof, which provide a cured product having excellent mechanical strength and have a low viscosity.
The epoxy resin and epoxy resin composition of the present invention are extremely useful for a wide range of applications such as molding materials, casting materials, laminate materials, composite materials, paints, adhesives, and resists.

[0002]

2. Description of the Related Art Epoxy resins can be cured with various curing agents to give cured products having generally 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, 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, as the molecular weight of the above-mentioned general-purpose epoxy resin increases, the mechanical strength of a cured product obtained by using the resin increases, but the viscosity also increases and the workability decreases. There is a disadvantage that.

[0004]

In view of these circumstances, the present inventors have conducted intensive studies to provide a cured product having excellent mechanical strength and low viscosity, and as a result, have found that an epoxy resin having a specific molecular structure has been obtained. The inventors have found that the resin has a low viscosity and imparts excellent toughness (mechanical strength) to the cured product, and have completed the present invention.

That is, the present invention relates to (1) Formula (1)

[0006]

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(Wherein, n is an average value and represents a positive number and is a value greater than 0 and not more than 20. R represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms, and G represents glycidyl. Represents a group.)

(2) (a) an epoxy resin composition containing (a) the epoxy resin described in (1), (b) 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) and (4) Or a cured product obtained by curing the epoxy resin composition according to item 1.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

The compound represented by the formula (1) is, for example, a compound represented by the formula (2)

[0011]

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(Wherein, R has the same meaning as in formula (1))

The reaction of the compound represented by the formula with epihalohydrin can be carried out in the presence of an alkali metal hydroxide.

In the compound represented by the formula (2), the value of n is an average value, represents a positive number, and is a value greater than 0 and 20 or less, preferably 0.01 to 15, particularly preferably 0 to 15. 0.5 to 5.

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 compound of the formula (2) and an excess of epihalohydrin such as epichlorohydrin or epibromohydrin, or 20 to 12 while adding.
The epoxy resin of the present invention can be obtained by reacting at 0 ° C. for 1 to 10 hours.

In the reaction for obtaining the epoxy resin 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 formula (2) and epihalohydrin at 20 to 120 ° C. A solid or aqueous solution of an alkali metal hydroxide is added, and 20 to 120
A method of reacting at a temperature of ° C. to remove hydrogen halide (ring closure) may be used. In this case, the reaction time is usually 0.5 to 10 hours.

The amount of epihalohydrin used in these reactions is usually 1 to 20 mol, preferably 2 to 10 mol, per 1 equivalent of the hydroxyl group of the compound represented by the formula (2). The amount of the alkali metal hydroxide to be used is generally 0.8 to 1 equivalent of the hydroxyl group in the compound represented by the formula (2).
2.0 mol, preferably 0.9 to 1.8 mol. Further, dimethyl sulfone to promote the reaction smoothly,
The reaction is preferably performed by adding an aprotic polar solvent such as dimethyl sulfoxide. In this case, the reaction time is usually 1 to 8 hours.

The aprotic polar solvent is used in an amount of usually 5 to 150% by weight, preferably 10 to 150% by weight, based on the amount of epihalohydrin.
140% by weight is used as needed.

The reaction product of these epoxidation reactions may be 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. Further, in order to further reduce the amount of hydrolyzable halogenated epoxy resin, the recovered epoxy resin is dissolved again in a solvent such as toluene, methyl isobutyl ketone, methyl ethyl ketone, and an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide. An aqueous solution can be added for further reaction to ensure ring closure. In this case, the amount of the alkali metal hydroxide to be used is usually 0.1 to 1 equivalent of the hydroxyl group of the compound of the formula (2) used for the epoxidation.
It is from 0.01 to 0.3 mol, preferably from 0.05 to 0.2 mol. The reaction temperature is usually 50 to 120 ° C, and the reaction time is usually 0.5 to 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.

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

Other epoxy resins which can be used in combination with the epoxy resin 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 0.7 to 1.2 equivalents per 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 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 an amount occupying 0 to 90% by weight in the epoxy resin composition of the present invention. 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 containing the epoxy resin of the present invention, the curing agent and, if necessary, a curing accelerator can be easily obtained as a cured product by a method similar to a conventionally known method. For example, the epoxy resin of the present invention and a compounding material such as a curing agent and, if necessary, a curing accelerator and a filler are optionally used in an extruder,
The epoxy resin composition was thoroughly mixed using a die, roll, etc. until uniform, and the epoxy resin composition was melted and then molded using a casting or transfer molding machine. The cured product of the present invention can be obtained by heating at 200 ° 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 a mixture of 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 has excellent mechanical strength, and the epoxy resin and the epoxy resin composition before curing have low viscosity and good workability. Therefore, a wide range of fields requiring mechanical strength and low viscosity are required. Can be used. 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.

[0031]

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 flask equipped with a thermometer, a dropping funnel, a cooling tube, and a stirrer was purged with nitrogen gas and subjected to the following formula (3).

[0033]

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(In the formula, the average value of n is 2.6.)

289 parts of the compound represented by the following formula were dissolved in 370 parts of epichlorohydrin, and 5 parts of tetramethylammonium chloride was added. The mixture was further heated to 45 ° C., and 60 parts of flaky sodium hydroxide was added in portions over 100 minutes, and then the mixture was further reacted at 45 ° C. for 3 hours. After completion of the reaction, the resultant 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 690 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 is distilled off from the oil layer under heating and reduced pressure to obtain the following formula (4)

[0037]

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(Wherein, the average value of n is 2.6, and G represents a glycidyl group.)

The epoxy resin (A) 2 of the present invention represented by the formula:
93 parts were obtained. The obtained epoxy resin was liquid and the epoxy equivalent was 363 g / eq.

Example 2 In Example 1, the average value of n in the equation (3) was 2.
The reaction was carried out in the same manner as in Synthesis Example 1 except that 385 parts of the compound of 4.8 was used instead of 6 to obtain 374 parts of the epoxy resin (B) of the present invention represented by the above formula (4). The obtained epoxy resin was liquid and had an epoxy equivalent of 459 g /
eq.

Examples 3 and 4, Comparative Example 1 The epoxy resin (A) and the epoxy resin (B) obtained in Examples 3 and 4 were treated with methylnadic anhydride (Kayahard MCD, Nippon Kayaku Co., Ltd.) as a curing agent. ))
Using 2-methyl-4-ethylimidazole (2E4MZ) as a curing accelerator, the components were blended at the ratios shown in the column of the composition of the formulation in Table 1, mixed, cast, and then poured at 80 ° C. for 2 hours.
The test piece was prepared by curing at 20 ° C. for 2 hours and at 200 ° C. for 5 hours, and the flexural strength was measured according to JIS K-6911. Table 1 shows the results. In addition, the numerical value in the column of the composition of the compound in the table represents part.

[0042]

[Table 1]

From Table 1, it is clear that the cured product of the epoxy resin of the present invention shows high bending strength.

[0044]

The epoxy resin of the present invention is a liquid and gives a cured product having excellent mechanical strength as compared with conventionally used epoxy resins. That is, the epoxy resin of the present invention can provide a cured product having excellent mechanical strength, and is extremely useful for a wide range of applications such as molding materials, casting materials, laminate materials, paints, adhesives, and resists.

Claims (5)

[Claims] (1) Formula (1) (Where n is an average value and represents a positive number and is greater than 0 and 20
The following values are shown. R independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms, and G represents a glycidyl group. Epoxy resin represented by). 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.