JPH10195174A - Epoxy resin, epoxy resin composition and cured material made therefrom - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin which has low viscosity, gives a cured material excellent in toughness and is useful for a molding material, a casting material, a laminating material, a composite material, a coating material, an adhesive, a resist, etc., by using a hydrogenated bisphenol A compound having both ethylene oxide groups having a specified number of repeating units and glycidyl groups. SOLUTION: This epoxy resin is represented by formula I (wherein n is 1 to 10; and G is glycidyl). It is obtained, for example, by reacting a dissolved mixture of a compound of formula II and an excess of an epihalohydrin, such as epichlorohydrin or epibromohydrin, with an alkali metal hydroxide, such as sodium or potassium hydroxide, at 20-120 deg.C after or while the alkali metal hydroxide is added to the dissolved mixture, or by adding a catalyst comprising a quaternary ammonium salt, such as tetramethylammonium chloride or tetramethylammonium bromide, to a dissolved mixture of a compound of formula II and an epihalohydrin to effect dehydrohalogenation (ring closure).

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. Epoxy resin and epoxy resin composition of the present invention is a molding material,
It is extremely useful for a wide range of applications such as casting materials, laminated materials, composite materials, paints, adhesives, resists, etc.

[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 laminated boards, 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 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 drawback 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 deteriorate.

[0004]

In view of these circumstances, the present inventors have earnestly studied for a bifunctional epoxy resin which gives a cured product excellent in mechanical strength and has a low viscosity, and as a result, has a specific molecular structure. It was found that the epoxy resin having a low viscosity has a low viscosity and imparts excellent toughness to the cured product, and has completed the present invention.

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

[0006]

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(In the formula, n is a positive number of 1 to 10 and represents an average value, and G represents a glycidyl group.) (2) (a) The epoxy described in (1) above. Resin (b) Epoxy resin composition containing a curing agent, (3) Epoxy resin composition according to the above (2) containing a curing accelerator, (4) Above (2) containing an inorganic filler or (3) The epoxy resin composition according to (3), and (5) a cured product obtained by curing the epoxy resin composition according to any one of (2), (3) and (4) above. .

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION

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

[0010]

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(Wherein n has the same meaning as in formula (1), preferably 1 to 5). The reaction of epihalohydrin with the compound represented by the formula (I) is carried out in the presence of an alkali metal hydroxide. Can be obtained by

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. To a dissolved mixture of the compound of the formula (2) and an excess of epihalohydrin such as epichlorohydrin and epibromhydrin, add or add an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide to a temperature of 20 to 120 ° C. To give the epoxy resin of the present invention.

In the reaction for obtaining the epoxy resin of the present invention, an aqueous solution of the alkali metal hydroxide may be used, and in that case, an 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 distilled off 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. Add a solid or aqueous solution of alkali metal hydroxide to 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 preferably 0.5 to 10 hours.

The amount of epihalohydrin usually used in these reactions is usually 1 to 20 mol, preferably 2 to 10 mol, based on 1 equivalent of the hydroxyl group of the compound represented by the formula (2). The amount of the alkali metal hydroxide used is 0.8 to 2.0 with respect to 1 equivalent of the hydroxyl group in the compound represented by the formula (2).
The molar amount is preferably 0.9 to 1.8 mol. Further, in order to allow the reaction to proceed smoothly, it is preferable to carry out the reaction by adding an aprotic polar solvent such as dimethyl sulfone or 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, the mixture is heated to 100 to 150 ° C. under reduced pressure.
Epihalohydrin and other additional solvents are removed at a pressure of 10 mmHg or less. 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. It is also possible to add an aqueous solution and carry out further reaction to ensure ring closure.
In this case, the amount of alkali metal hydroxide used is preferably 0.01 to 0.3 mol, and particularly preferably 0.05 to 0.3 mol, based on 1 equivalent of hydroxyl group of the phenol resin used for epoxidation.
It is 0.2 mol. The reaction temperature is 50 to 120 ° C., and the reaction time is usually 0.5 to 2 hours.

After the completion of the reaction, the produced 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 heating and reduced pressure to obtain the epoxy resin of the present invention.

The epoxy resin composition of the present invention will be described below. 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 resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin and the like. Or two or more may be used in combination.

As the curing agent used in the epoxy resin composition of the present invention, for example, amine compounds, acid anhydride compounds, amide compounds, phenol compounds and the like can be used. 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 relative to 1 equivalent of epoxy groups 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 using the above-mentioned curing agent, 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, and 1,8-diaza. Examples thereof include tertiary amines such as bicyclo (5,4,0) undecene-7, phosphines such as triphenylphosphine, and metal compounds such as tin octylate. The curing accelerator may be used in an amount of 0.1 to 5.0 parts by weight based on 100 parts by weight of the epoxy resin.

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 of 0 to 90% by weight in the epoxy resin composition of the present invention. Further, 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 to the epoxy resin composition of the present invention.

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 by using an extruder, a kneader, a roll, etc. until they become uniform. To obtain an epoxy resin composition. The epoxy resin composition is 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 2-10 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 to prepare glass fiber, carbon fiber, polyester fiber, polyamide fiber, alumina fiber, paper and the like. A prepreg obtained by impregnating the base material with heat and drying can also be hot-press molded 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, so that mechanical strength and low viscosity are required in a wide range of fields. Can be used. Specifically, all kinds of electrical materials such as sealing materials, laminated boards, 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.

[0028]

EXAMPLES Next, the present invention will be described more specifically by way of Examples and Comparative Examples. In the following, parts are parts by weight unless otherwise specified.

Example 1 A flask equipped with a thermometer, a dropping funnel, a condenser, and a stirrer was purged with nitrogen gas while being represented by the above formula (2) (wherein the average value of n is 1.1). Compound 1
68 parts were dissolved in 370 parts of epichlorohydrin, and 5 parts of tetramethylammonium chloride was added. Further heat to 45 ° C and add 60 parts of flaky sodium hydroxide to 1
The reaction mixture was added portionwise over 00 minutes and then 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, this solution of methyl isobutyl ketone is heated to 70 ° C. and a 30 wt% sodium hydroxide aqueous solution 1
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,
Methyl isobutyl ketone was distilled off from the oil layer under reduced pressure by heating using a rotary evaporator to obtain 211 parts of the epoxy resin (A) of the present invention represented by the formula (1) (wherein the average value of n is 1.1). The obtained epoxy resin is a low-viscosity liquid and has an epoxy equivalent of 239 g / e.
It was q.

Example 2 In Example 1, the average value of n in the equation (2) was 1.
Instead of the compound which is 1, the compound which is 1.6 is 190
The reaction was carried out in the same manner as in Example 1 except that the above-mentioned parts were used to obtain 233 parts of the epoxy resin (B) of the present invention represented by the formula (1). The obtained epoxy resin was a low-viscosity liquid, and the epoxy equivalent was 260 g / eq (in the formula, the average value of n is 1.6).

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 at a ratio (weight ratio) shown in the column of the composition of the composition in Table 1, mixing, casting, and then casting at 80 ° C for 2 hours. The specimen was cured at 120 ° C. for 2 hours and at 200 ° C. for 5 hours to prepare a test piece, and the bending strength was measured. The results are shown in Table 1.
Are also shown.

Flexural strength A method according to JIS K-6911.

[0034]

[Table 1] Table 1 Example Example 3 4 Composition of composition Epoxy resin (A) 100 Epoxy resin (B) 100 Kayahard MCD 67 62 2E4MZ 1 1 Physical properties of cured product Bending strength (kg / mm ² ) 15.1 15.3

From Table 1, the cured product of the epoxy resin of the present invention shows a high bending strength, and the epoxy resin before curing is a liquid having a low viscosity.

[0036]

INDUSTRIAL APPLICABILITY The epoxy resin of the present invention is a low-viscosity liquid and gives a cured product excellent in mechanical strength as compared with the epoxy resins which have been generally used in the past. It is extremely useful for a wide range of applications such as laminate materials, paints, adhesives, resists, and the like.

Claims (5)

[Claims] (1) Formula (1) (Wherein, n is a positive number of 1 to 10 and represents an average value, and G represents a glycidyl group). 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, which contains an inorganic filler. 5. A cured product obtained by curing the epoxy resin composition according to any one of claims 2, 3 and 4.