JP3441020B2 - Epoxy resin, epoxy resin composition and cured product thereof - Google Patents

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 heat resistance, water resistance and mechanical strength.

[0002]

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

[0003]

However, the general-purpose epoxy resin as described above has a drawback that as the molecular weight increases, the toughness of the cured product obtained by curing the epoxy resin increases, but the heat resistance decreases. Further, although a cured product obtained by mixing a polyfunctional epoxy resin such as cresol novolac epoxy resin in order to compensate for the decrease in heat resistance has high heat resistance, it has a drawback that toughness decreases and water absorption also increases. . On the other hand, with the recent remarkable development of the electronic industry and the like, the heat resistance, water resistance and mechanical strength (eg toughness) required for electrical insulating materials used for these have become increasingly severe, and these characteristics are excellent. The advent of epoxy resins has long been awaited.

[0004]

In view of these circumstances, the present inventors have earnestly studied for an epoxy resin that gives a cured product excellent in heat resistance, water resistance and mechanical strength, and as a result, have found that an epoxy resin having a specific molecular structure is obtained. It has been found that the resin imparts excellent heat resistance, water resistance and mechanical strength to the cured product, and has completed the present invention.

That is, the present invention is Expression (1)

[0006]

[Chemical 2]

(In the formula, n represents an average value and takes a value of 0 to 10. m takes an integer value of 0 to 3. R and Q are hydrogen atoms,
Each of R and Q, which represents a halogen atom, an alkyl group having 1 to 8 carbon atoms or an aryl group, may be the same as or different from each other. G represents a glycidyl group. ) Epoxy resin represented by

(2) An epoxy resin composition containing the epoxy resin and the curing agent described in (1) above, and optionally a curing accelerator, and (3) a curing obtained by curing the epoxy resin composition described in (2) above. It is intended to provide things.

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

[0010]

[Chemical 3]

(In the formula, m, R and Q have the same meanings as in formula (1).)

It can be obtained by carrying out the reaction between the compound represented by and epihalohydrin in the presence of an alkali metal hydroxide.

The compound represented by the formula (2) includes, for example, the formula (3)

[0014]

[Chemical 4]

Or equation (4)

[0016]

[Chemical 5]

Or equation (5)

[0018]

[Chemical 6]

Or equation (6)

[0020]

[Chemical 7]

Examples thereof include compounds represented by, but are not limited to these.

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 in advance to a dissolved mixture of the compound represented by the formula (2) obtained above and excess epichlorohydrin such as epichlorohydrin or epibromhydrin, Or 1 to 1 at a temperature of 20 to 120 ° C. while adding
The epoxy resin of the present invention can be obtained by reacting for 0 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 that case, the aqueous solution of the alkali metal hydroxide is continuously added to the reaction system. Water and epihalohydrin may be continuously distilled off under reduced pressure or normal pressure, and the liquid may be further separated to remove water and the epihalohydrin may be continuously returned to the reaction system.

Further, 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, and the mixture is added at 50 to 150 ° C. 1-5
A solid or aqueous solution of an alkali metal hydroxide is added to the halohydrin etherified product of the compound of formula (2) obtained by reacting for a period of time, and again reacted at a temperature of 20 to 120 ° C. for 1 to 10 hours to dehydrohalogenate ( A method of ring closure) may be used.

Usually, the amount of epihalohydrin 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 15 mol, preferably 0.9 to 11 mol, based on 1 equivalent of the hydroxyl group of the compound represented by the formula (2). 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 addition to alcohols such as methanol and ethanol.

When alcohols are used, the amount used is 2 to 20% by weight, preferably 4 to 15% by weight, based on the amount of epihalohydrin. When an aprotic polar solvent is used, it is 5 to 100 relative to the amount of epihalohydrin.
%, Preferably 10 to 90% by weight.

After washing these reaction products of the epoxidation reaction with or without washing with water under reduced pressure at 110 to 250 ° C.,
Distillation is performed at a pressure of 10 mmHg or less to remove epihalohydrin and other added solvents. To ensure the ring closure and to make an epoxy resin with less hydrolyzable halogen, dissolve the obtained epoxy resin in a solvent such as toluene or methyl isobutyl ketone, and then use an alkali metal water such as sodium hydroxide or potassium hydroxide. It is also possible to add an aqueous solution of an oxide to carry out the 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 1 equivalent of the hydroxyl group of the compound represented by the formula (2) used for epoxidation.
~ 0.2 mol. In this case, the reaction temperature is 50 to 120.
The reaction temperature 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 and methyl isobutyl 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 can be obtained by uniformly mixing the epoxy resin of the present invention, a curing agent, and optionally a curing accelerator. In the epoxy resin composition of the present invention, an epoxy resin other than the epoxy resin of the present invention can be used in combination as the epoxy resin. When other epoxy resin is used in combination, the proportion of the epoxy resin of the present invention in the total epoxy resin is 20% by weight.
The above is preferable. In the epoxy resin composition of the present invention, amine compounds, acid anhydride compounds, amide compounds, phenol compounds and the like can be used as the curing agent. 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, trianhydride. Mellitic acid, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnaphthic acid, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, phenol novolac, and modified products thereof, Examples thereof include imidazole, BF ₃ -amine complex, and guanidine derivative. Further, the compound represented by the formula (2) used as a raw material of the epoxy resin of the present invention can also be used as a curing agent. These curing agents may be used alone or in combination of two or more.

The amount of these curing agents used is preferably 0.7 to 1.2 equivalents per 1 equivalent of the epoxy group of the epoxy resin. If the amount is less than 0.7 equivalent or more than 1.2 equivalent to 1 equivalent of the epoxy group, the 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. Examples of usable curing accelerators include imidazoles such as 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2- (dimethylaminomethyl) phenol, and the like.
1,8-diaza-bicyclo (5,4,0) undecene-
And tertiary amines such as 7; phosphines such as triphenylphosphine; and metal compounds such as tin octylate. When the curing accelerator is used, the amount used is 0.1 to 5.0 parts by weight based on 100 parts by weight of the epoxy resin, if necessary. Furthermore, to the epoxy resin composition of the present invention, various compounding agents such as a filler such as silica, alumina and talc, a silane coupling agent, a release agent and a pigment can be added, if necessary.

The epoxy resin composition of the present invention containing the epoxy resin of the present invention, a curing agent and, if necessary, a curing accelerator can be easily made into a cured product by the same method as a conventionally known method. For example, the epoxy resin of the present invention and a curing agent, a filler and other additives are sufficiently mixed by using an extruder, a kneader, a roll or the like, if necessary, until they are homogeneous, and the epoxy resin of the present invention A resin composition is obtained, and the epoxy resin composition is melted and then molded using a casting or transfer molding machine and the like, and further 2 to 10 at 80 to 200 ° C.
A cured product can be obtained by heating for a period of time.

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 a base material with heating and drying can be hot-press molded to obtain a cured product.

The amount of the diluent solvent used in this case is usually 10 in the mixture of the epoxy resin composition of the present invention and the diluent solvent.
˜70 wt%, preferably 15-65 wt%.

Since the cured product thus obtained has excellent heat resistance, water resistance and mechanical strength, it can be used in a wide range of fields where heat resistance and water resistance are required. Specifically, it is useful as any electric / electronic material such as a sealing material, a laminated plate, an insulating material, and the like. It can also be used in the fields of molding materials, adhesives, composite materials, paints and the like.

[0036]

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

Example 1 A flask equipped with a thermometer, a dropping funnel, a cooling tube and a stirrer was charged with nitrogen gas while 214 parts of the compound represented by the formula (3) and 740 parts of epichlorohydrin,
370 parts of dimethyl sulfoxide was charged and dissolved. Further, it is heated to 50 ° C. to form flaky sodium hydroxide (purity 9
9%) 80.8 parts were added portionwise over 90 minutes, and then the mixture was further reacted at 60 ° C. for 2 hours and at 70 ° C. for 1 hour. After completion of the reaction, dimethylsulfoxide and epichlorohydrin were distilled off under reduced pressure while heating at 130 ° C., and 652 parts of methyl isobutyl ketone was added to the residue to dissolve it.

Further, this solution of methyl isobutyl ketone was heated to 70 ° C. and a 30% by weight aqueous solution of sodium hydroxide 2
After adding 0 part and reacting for 1 hour, washing with water was repeated 3 times to make the pH neutral. Further, the water layer is separated and removed, and methyl isobutyl ketone is distilled off from the oil layer under heating and reduced pressure by using a rotary evaporator to obtain the following formula (7).

[0039]

[Chemical 8]

There was obtained 312 parts of the epoxy resin (A) of the present invention represented by the formula (G represents a glycidyl group). The obtained epoxy resin was liquid and had an epoxy equivalent of 18
It was 3 g / eq. The value of n calculated from the epoxy equivalent was 0.15.

Example 2, Comparative Example 1 Epoxy resin (A), and as a comparison, a liquid bisphenol A type epoxy resin (Epicoat 828, manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 186 g / eq, epoxy resin (B)). Compounded with the composition shown in Table 1, using methyl nadic acid anhydride (Kayahard MCD, manufactured by Nippon Kayaku Co., Ltd.) as a curing agent, and 2-ethyl-4-methylimidazole (2E4MZ) as a curing accelerator. Then mix and cast, 80 ° C for 2 hours, 120 ° C for 2 hours,
Further, it was cured at 200 ° C. for 5 hours to prepare a test piece, and its glass transition point and water absorption were measured. The results are shown in Table 1.
The conditions for measuring the glass transition point, water absorption and bending strength are as follows. Further, in the table, the numerical value in the column of composition of formulation shows parts by weight.

[0042] Glass transition point       Thermomechanical measuring device (TMA): TM-7000 manufactured by Vacuum Riko Co., Ltd.       Temperature rising rate: 2 ° C / min Water absorption       Test piece (cured product): Diameter 50 mm                         3mm thick disc       Weight increase rate (%) after boiling for 1 hour in 100 ° C water Bending strength       Value based on JIS K-6911

[0043]

Table 1 Table 1 Example 1 Comparative Example 1 Composition of compound Epoxy resin (A) 100 Epoxy resin (B) 100 (Epoxy equivalent (g / eq)) 183 186 Kayahard MCD 87.5 86 2E4MZ 1 1 Physical properties of cured product Glass transition point (℃) 181 175 Water absorption rate (%) 0.24 0.34 Bending strength (Kg / mm ² ) 14.3 12.0

From Table 1, the cured product of the epoxy resin of the present invention exhibited a higher glass transition point, a lower water absorption rate and a higher mechanical strength than the cured products of known epoxy resins.

[0045]

The epoxy resin of the present invention can provide a cured product having excellent heat resistance, water resistance and mechanical strength, and can be used as a sealing material, a molding material, a casting material, a laminating material, a paint, It is extremely useful for a wide range of applications such as adhesives and resists.

Continuation of the front page (56) Reference JP-A-7-292066 (JP, A) JP-A-5-117350 (JP, A) JP-A-3-252451 (JP, A) JP-A-63-159418 (JP , A) JP-A-5-1265 (JP, A) JP-A-6-157710 (JP, A) JP-A-8-120057 (JP, A) JP-A-64-56721 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) C08G 59/06 C08G 59/20 C07D 303/27

Claims (3)

(57) [Claims] 1. A formula (1): (In the formula, n represents an average value and takes a value of 0 to 10. m is 0.
Takes an integer value of ~ 3. R and Q each represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 8 carbon atoms, or an aryl group, and each R and Q may be the same or different from each other. G represents a glycidyl group. ) Epoxy resin represented by. 2. An epoxy resin composition containing the epoxy resin according to claim 1 and a curing agent, and optionally a curing accelerator. 3. A cured product obtained by curing the epoxy resin composition according to claim 2.