JPH10147631A - Epoxy compound, epoxy resin composition and its cured material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy compound having a specific molecular structure, a low-viscosity epoxy resin composition containing the epoxy compound and its cured material excellent in mechanical strength and water resistance. SOLUTION: This compound is shown by formula I ((n) is an average value and is a positive number of 1-3; G is glycidyl). The compound is obtained, for example, by reacting a dissolved mixture of a compound of formula II with an excessive amount of an epihalohydrin such as epichlorohydrin or epibromohydrin at 20-120 deg.C by adding an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide or while adding the alkali metal hydroxide. In the reaction, preferably the amount of the epihalohydrin is about 1-20mols based on 1 equivalent of hydroxyl group of the compound of formula II and the amount of the alkali metal hydroxide used is about 0.8-2.0mol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy compound and an epoxy resin composition which provide a cured product having excellent mechanical strength and have a low viscosity, and a cured product thereof. It is extremely useful for a wide range of applications such as molding materials, casting materials, laminate materials, composite materials, 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. . Further, there is also a problem that the viscosity of the epoxy resin composition before curing also increases and the workability decreases.

[0004]

In view of these circumstances, the present inventors have conducted intensive studies for an epoxy resin composition which provides a cured product having excellent mechanical strength and water resistance and has a low viscosity. The present inventors have found that an epoxy resin composition containing an epoxy compound having a molecular structure has a low viscosity and imparts excellent mechanical strength and water resistance to a cured product thereof, thereby completing the present invention.

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

[0006]

Embedded image

(2) (a) an epoxy compound represented by the formula (1), wherein n is an average value and represents a positive number of 1 or more and 3 or less, and G represents a glycidyl group. Epoxy compound (b) Epoxy resin (c) Epoxy resin composition containing a curing agent, (3) epoxy resin composition according to the above (2) containing a curing accelerator, (4) containing an inorganic filler (5) A cured product obtained by curing the epoxy resin composition according to (2), (3) or (4). .

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION

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

[0010]

Embedded image (In the formula, n represents 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.

As a method for obtaining the epoxy compound 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.
By reacting at 0 ° C., the epoxy compound of the present invention can be obtained.

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 (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 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 2.0 with respect to 1 equivalent of the hydroxyl group in the compound represented by the formula (2).
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 an aprotic polar solvent such as dimethyl sulfone and dimethyl sulfoxide. In this case, the reaction time is usually 1 to 8 hours.

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

The reaction product obtained by these epoxidation reactions is washed with water or without heating under reduced pressure under heating for 100 hours.
Epihalohydrin and other additional solvents are removed at a temperature of 150 ° C. and a pressure of 10 mmHg or less. In order to further reduce the amount of hydrolyzable halogenated epoxy compound, the recovered epoxy compound is dissolved again in a solvent such as toluene, methyl isobutyl ketone or methyl ethyl ketone, and an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is dissolved. 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 the hydroxyl group 1 of the compound of the formula (2) used for the epoxidation.
It is usually 0.01 to 0.3 mol, preferably 0.05 to 0.2 mol, per equivalent. The reaction temperature is usually 50 to 1
At 20 ° C, 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 compound of the present invention.

Hereinafter, the epoxy resin composition of the present invention will be described. The epoxy resin composition of the present invention contains the epoxy compound of the present invention, a difunctional or higher functional epoxy resin, and a curing agent. In the epoxy resin composition of the present invention, the epoxy compound of the present invention usually accounts for 2 to 40% by weight, preferably 5 to 30% by weight of the total amount of the bifunctional or higher epoxy resin and the epoxy compound of the present invention. use.

Specific examples of the bifunctional or higher functional epoxy resin include novolak type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin and the like. Also, two or more kinds 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.

In the epoxy resin composition of the present invention, the curing agent is used in an amount of 1 equivalent of epoxy group in the epoxy compound of the present invention and an epoxy resin having two or more functional groups (hereinafter, these are collectively referred to as a total epoxy resin component). On the other hand, 0.7-1.
Two equivalents are preferred. 0.7 equivalent to 1 equivalent of epoxy group
If the amount is less than the equivalent, or if the amount exceeds 1.2 equivalents, the 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, for example, imidazoles such as 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2- (dimethylaminomethyl) phenol, and 1,8-diaza. Tertiary amines such as -bicyclo (5,4,0) undecene-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 all the epoxy resin components as needed.

The epoxy resin composition of the present invention contains an inorganic filler if necessary. 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 above components at a predetermined ratio.
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, an extruder, if necessary, including all epoxy resin components and a curing agent, a curing accelerator if necessary, an inorganic filler and a compounding agent,
Mix well using a kneader, a roll or the like until uniform, to obtain an epoxy resin composition, melt the epoxy resin composition and then mold it using a casting or transfer molding machine. The cured product of the present invention can be obtained by heating at 80 to 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 is used to prepare 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. The solvent in this case is usually 10 to 70% by weight, preferably 1% by weight in the mixture of the epoxy resin composition of the present invention and the solvent.
An amount occupying 5 to 70% by weight, particularly preferably 15 to 65% by weight, is used.

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 can be used in a wide range of fields. Specifically, it is useful as any electric or electronic material such as a sealing material, a laminate, or an insulating material. Further, it can be used in the fields of molding materials, adhesives, composite materials, paints, and the like.

[0028]

EXAMPLES The present invention will now be described more specifically with reference to examples and comparative examples. In the following, parts are by weight unless otherwise specified.

Example 1 155 parts of the compound represented by the above formula (2) (the average value of n is 2.1) was added to a flask equipped with a thermometer, a dropping funnel, a cooling tube and a stirrer while purging with nitrogen gas. It was dissolved in 370 parts of epichlorohydrin, and 2.5 parts of tetramethylammonium chloride was added. The mixture was further heated to 70 ° C., and 20 parts of flaky sodium hydroxide was added in portions over 100 minutes. Thereafter, the mixture was further reacted at 70 ° C. for 3 hours.
After completion of the reaction, the product 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.
Of methyl isobutyl ketone was added and dissolved.

Further, the solution of methyl isobutyl ketone was heated to 70 ° C., and a 30% by weight aqueous sodium hydroxide solution 5 was added.
Then, after washing for 1 hour, washing with water was repeated until the pH of the washing solution became 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 to obtain the epoxy compound (A) of the present invention represented by the above formula (1). The obtained epoxy compound is liquid and has an epoxy equivalent of 367 g / e.
q.

Examples 2 and 3, Comparative Example 1 The epoxy compound (A) obtained in Example 1 and a liquid bisphenol A type epoxy resin (Epicoat 828, manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 186 g / e)
q, using methylnadic anhydride (Kayahard MCD, manufactured by Nippon Kayaku Co., Ltd.) as a curing agent for the epoxy resin (B) in Table 1) and 2-methyl-4- as a curing accelerator
Ethyl imidazole (2E4MZ) was blended at the ratio shown in the composition column of Table 1 and mixed to prepare a liquid epoxy resin composition of the present invention.
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 and water absorption were measured under the following conditions. The results are shown in Table 1.

Flexural strength A method according to JIS K-6911. Water absorption Test piece (cured product): Disk with a diameter of 50 mm and a thickness of 3 mm Weight gain after boiling in water at 100 ° C. for 24 hours (%)

[0033]

Table 1 Example 1 Comparative Example 23 1 Composition of the compound Epoxy compound (A) 10 150 Epoxy resin (B) 90 85 100 Kayahard MCD 82 80 86 2E4MZ 11 1 Physical properties of cured product Flexural strength (kg) / mm ² ) 13.5 13.4 12.0 Water absorption (%) 1.19 1.15 1.25

From Table 1, it is clear that the cured product of the epoxy resin composition of the present invention exhibits high bending strength and low water absorption.

[0035]

The epoxy resin composition containing the epoxy compound of the present invention is a low-viscosity liquid and has excellent mechanical strength and water resistance as compared with epoxy resin compositions which have been generally used in the past. Give a cured product. That is, the epoxy resin composition containing the epoxy compound of the present invention is extremely useful for a wide range of applications such as molding materials, casting materials, laminate materials, paints, adhesives, and resists.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08K 3:22)

Claims (5)

[Claims] (1) Formula (1) (Where n is an average value and represents a positive number of 1 or more and 3 or less,
G represents a glycidyl group. An epoxy compound represented by). 2. An epoxy resin composition comprising (a) the epoxy compound according to claim 1, (b) a bifunctional or higher epoxy resin, and (c) 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 claim 2, 3 or 4.