JPH1077330A - Epoxy resin, epoxy resin composition and its cured material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject resin useful as a casting material, etc., having a specific molecular structure, capable of providing a cured material excellent in mechanical strength and low in viscosity. SOLUTION: This resin is shown by formula I ((n) is an average value and a positive number; R is H, a halogen or a 1-4C alkyl; G is glycidyl; X is a group of formula II, CH2 , etc.). The resin is obtained, for example, by adding an alkali metal hydroxide such as sodium hydroxide to a dissolved molecular weight of a compound of formula III and an excessive epihalohydrin such as epichlorohydrin and reacting the compounds at 20-120 deg.C or reacting the compounds while adding the alkali metal hydroxide. Preferably, an epoxy resin composition comprising the resin, a curing agent, a curing promoter and an inorganic filler is cured to give the objective cured material.

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 resin and the 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 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, 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. In order to improve this point, a monofunctional reactive diluent may be added, but in such a case, there is a problem that various properties of the cured product are reduced.

[0004]

In view of these circumstances, the present inventors have conducted intensive studies in search of a bifunctional epoxy resin which provides a cured product having excellent mechanical strength and a low viscosity, and as a result, has a specific molecular structure. It has been found that an epoxy resin having a low viscosity has excellent toughness in a cured product thereof, and the present invention has been completed.

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

[0006]

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(Where n is an average value and represents a positive number.
Represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms, and G represents a glycidyl group. X represents any of the structures in the formula (2). )

[0008]

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(2) (a) an epoxy resin composition containing the epoxy resin described in (1) above, (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. In the epoxy resin of the present invention, the value of n is an average value, preferably from 0 to 20, particularly preferably from 0 to 20.
01 to 15 are preferred.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION

The compound represented by the formula (1) is, for example, a compound represented by the formula (3)

[0012]

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(Wherein, R represents the same meaning as in formula (1), and X represents any of the structures in formula (2).)

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 (3), the value of n is an average value, preferably 0 to 20, more preferably 0.01 to 20.
15 is preferred.

As a method for obtaining the epoxy resin of the present invention from the compound represented by the formula (3), 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 phenol resin and an excess of epihalohydrin such as epichlorohydrin and epibromhydrin, or while adding, usually at 20 to 120 ° C. The epoxy resin of the present invention can be obtained by reacting at a temperature.

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 (3) and epihalohydrin at 20 to 120 ° C. A solid or aqueous solution of an alkali metal hydroxide is added, and usually 20 to 1
A method of reacting at a temperature of 20 ° C. for dehydrohalogenation (ring closure) may be used. In this case, the reaction time is usually 0.5 to 1
0 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 (3). 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 (3).
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.

When an aprotic polar solvent is used, it is 5 to 150% by weight, more preferably 10 to 140% by weight, based on the amount of epihalohydrin.

After the reaction product of the epoxidation reaction is washed with water or without washing under heat and 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 used is preferably 0.01 to 0.3 mol, particularly preferably 0.05 to 0.3 mol per equivalent of the hydroxyl group of the compound of the formula (3) used for the epoxidation.
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.

Specific examples of other epoxy resins that 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, and biphenyl type epoxy resins. Or two or more of them may be used in combination.

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 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 cured by a method similar to a conventionally known method. For example, the epoxy resin of the present invention and a curing agent, if necessary, a curing accelerator,
An epoxy resin composition is obtained by sufficiently mixing an inorganic filler, other compounding materials, and the like with an extruder, a kneader, a roll, or the like, as necessary, until the epoxy resin composition becomes uniform. Is melted, molded using a casting machine or a transfer molding machine, and further heated at 80 to 200 ° C. for 2 to 10 hours to obtain the cured product of the present invention.

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 has excellent mechanical strength, and the epoxy resin and the epoxy resin composition before curing have low viscosity and good workability. 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.

[0032]

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

Example 1 A flask equipped with a thermometer, a dropping funnel, a cooling pipe, and a stirrer was purged with nitrogen gas and subjected to the following formula (4).

[0034]

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(In the formula, the average value of n is 1.8.)

193 parts of the compound represented by the following formula was 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 500 parts of methyl isobutyl ketone was added to the residue and dissolved.

Further, the solution of methyl isobutyl ketone was heated to 70.degree.
After adding 0 parts and reacting for 1 hour, washing with water was repeated three times to make the pH neutral. Further, the aqueous layer was separated and removed, and methyl isobutyl ketone was distilled off from the oil layer under reduced pressure by heating using a rotary evaporator.

[0038]

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(In the formula, G represents a glycidyl group.)

The epoxy resin (A) 2 of the present invention represented by the formula:
24 parts were obtained. The obtained epoxy resin was a low-viscosity liquid and had an epoxy equivalent of 268 g / eq.

Example 2 In Example 1, the average value of n in the equation (3) was 1.
The reaction was conducted in the same manner as in Synthesis Example 1 except that 277 parts of the compound 3.7 was used instead of 8, to obtain 293 parts of the epoxy resin (B) of the present invention represented by the above formula (4). The obtained epoxy resin is a liquid having a low viscosity and an epoxy equivalent of 3
It was 51 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 in the proportions shown in the column of the composition of the formulation shown in Table 1, mixed, cast, and then cast at 80 ° C for 2 hours at 120 ° C. For 2 hours and at 200 ° C. for 5 hours to prepare a test piece, and the flexural strength was measured by a method according to JIS K-6911. The results are shown in Table 1.

[0044]

[Table 1]

As shown in Table 1, the cured product of the epoxy resin of the present invention has a high bending strength, and the epoxy resin before curing is a low-viscosity liquid.

[0046]

The epoxy resin of the present invention is a low-viscosity 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) (In the formula, n is an average value and represents a positive number, and R is each independently a hydrogen atom, a halogen atom, or a carbon number of 1-4.
And G represents a glycidyl group. Also,
X represents any of the structures in the formula (2). ) 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.