JPH111542A - Epoxy resin, epoxy resin composition and its cured product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin giving a cured product low in water- absorption properties and a dielectric constant by diglycidyletherifying a compound having a cyclohexyl group at the ortho-site of bisphenol A. SOLUTION: This resin is an epoxy resin expressed by formula I [(n) is 0-3; G is glycidyl group], and is obtained by adding an alkali metal hydroxide (e.g. sodium hydroxide, etc.), to a solution mixture between a compound of formula II and an excess epihalohydrin (e.g. epichlorohydrin, etc.), or by reacting them at 20-120 deg.C as adding the alkali metal hydroxide to the solution mixture mentioned above. The epoxy resin composition is obtained by containing (A) the resin of the formula I and (B) a hardener (e.g. diaminodiphenylmethane, etc.), preferably so that the component B may be contained in a quantity of 0.7-1.2 eq. based on one eq. of epoxy group of the component A. This objective cured product is obtained by heating the above-mentioned composition preferably at 80-200 deg.C for 2-10 h.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an epoxy resin which gives a cured product having excellent water resistance and low dielectric properties.

[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. In addition, a flame-retardant solid epoxy resin obtained by reacting tetrabromobisphenol A with a liquid bisphenol A epoxy resin is industrially used as a general-purpose epoxy resin.

[0003]

However, the above-mentioned general-purpose epoxy resin has a disadvantage that the viscosity increases as the molecular weight increases, and the toughness of a cured product obtained by using the resin increases, but the heat resistance decreases. There is. Further, a cured product obtained by mixing a polyfunctional epoxy resin such as a cresol novolak type epoxy resin to compensate for a decrease in heat resistance has a high heat resistance, but has a disadvantage of a high water absorption. In recent years, with the remarkable progress in the electric and electronic fields, especially with the increase in signal speed, the demand for low dielectric properties for the electrical insulating materials used in these fields has been increasing, which has excellent water resistance and low dielectric constant. The emergence of epoxy resins has been awaited.

[0004]

Means for Solving the Problems In view of such circumstances, the present inventors have conducted intensive studies in search of an epoxy resin having excellent water resistance and low dielectric properties of a cured product thereof. As a result, an epoxy resin having a specific molecular structure was obtained. Satisfy the characteristics described above, and have completed the present invention.

That is, the present invention provides (1) the following formula (1)

[0006]

Embedded image

(Where n is an average value and represents a positive number from 0 to 3; G represents a glycidyl group.) (2) (a) The epoxy resin according to the above (1) ,
(B) an epoxy resin composition containing a curing agent,
(3) The epoxy resin composition according to the above (2) containing a curing accelerator, (4) the epoxy resin composition according to the above (2) or (3) containing an inorganic filler, (5) the above (2) The present invention provides a cured product obtained by curing the epoxy resin composition according to any one of (3) and (4).

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION As a method for producing an epoxy resin of the present invention, a method generally known per se can be employed. Specifically, for example, equation (2)

[0009]

Embedded image

(Wherein n is an average value and represents a positive number of 0 to 3), and sodium hydroxide and hydroxide are added to a dissolved mixture of a compound represented by the formula (1) and an excess of epihalohydrin such as epichlorohydrin and epibromohydrin. 20 to 12 while adding or adding an alkali metal hydroxide such as potassium.
By reacting at 0 ° C., the epoxy resin of the present invention can be obtained.

In the reaction for obtaining the epoxy resin of the present invention, an aqueous solution of the alkali metal hydroxide may be used. In such a 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 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 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
The reaction may be carried out at a temperature of ° C. for dehydrohalogenation (ring closure).

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 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, in order to make the reaction proceed smoothly, it is preferable to add an alcohol such as methanol, ethanol and isopropanol, and an aprotic polar solvent such as dimethyl sulfone and dimethyl sulfoxide, and to carry out the reaction.

When an alcohol is used, its amount is usually 2 to 20%, preferably 4 to 15%, based on the amount of epihalohydrin. 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.

After the reaction product of these epoxidation reactions is washed with water or without water washing, under reduced pressure at 100 to 150 ° C.,
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 obtained epoxy resin is dissolved 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. The epoxy resin of the present invention represented by the formula (1) in the epoxy resin composition of the present invention can be used alone or in combination with another epoxy resin. Specific examples of other epoxy resins that can be used in combination with the epoxy resin of the present invention include novolak epoxy resins, bisphenol A epoxy resins, bisphenol F epoxy resins,
Biphenyl type epoxy resins and the like can be mentioned. These epoxy resins may be used alone or in combination of two or more.

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, and linolenic acid.
Polyamide resin synthesized from monomer and ethylenediamine, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride,
Polyhydric phenols such as methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, phenol novolak, aralkylene phenol resin and the like, and modified products thereof, imidazole, Examples include, but are not limited to, BF ₃ -amine complexes and guanidine derivatives. 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, 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 the epoxy resin as required.

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 as needed. Further, the epoxy resin composition of the present invention, a silane coupling agent, stearic acid, palmitic acid, zinc stearate,
Various compounding agents such as a release agent such as 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 epoxy resin, a curing agent, and, if necessary, a curing accelerator, an inorganic filler and a compounding agent are sufficiently mixed using an extruder, a kneader, a roll, or the like, as necessary, until the mixture is epoxy. A resin composition is obtained, and the epoxy resin composition is molded using a casting or transfer molding machine after melting, and preferably heated at 80 to 200 ° C. for 2 to 10 hours to obtain a cured product of the present invention. be able to.

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, etc., 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.

[0024]

EXAMPLES The present invention will be described more specifically with reference to the following Examples, in which parts are by weight unless otherwise specified.

Embodiment 1

While a nitrogen gas purge was applied to the flask equipped with a thermometer, a condenser and a stirrer, 196 parts of the compound represented by the formula (2), 370 parts of epichlorohydrin,
185 parts of dimethyl sulfoxide were charged and dissolved. ,
The mixture was further heated to 45 ° C., and 40 parts of flaky sodium hydroxide was added in portions over 100 minutes.
The reaction was carried out at 70 ° C. for 30 minutes. After completion of the reaction, dimethyl sulfoxide, excess epichlorohydrin and the like were distilled off under heating and reduced pressure at 130 ° C. using a rotary evaporator, and 504 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, the pH of the water washing solution was measured.
Was repeated until the 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.
239 parts of the epoxy resin (A) of the present invention represented by the following formula was obtained. The obtained epoxy resin (A) has a softening point of 47.5 ° C.
The epoxy equivalent was 266 g / eq, and the average value of n was 0.063.

Example 2 A phenol novolak (having a hydroxyl equivalent of 106 g / e) was used as a curing agent for the epoxy resin (A) obtained in Example 1.
q, manufactured by Nippon Kayaku Co., Ltd.) and triphenylphosphine (TPP) as a curing accelerator at a weight ratio shown in the composition column of Table 1 and rolled at 70 ° C. for 15 minutes. At 150 ° C and a molding pressure of 50 kg / cm ² .
After transfer molding for 80 seconds,
A test piece was prepared by curing at 180 ° C. for 8 hours, and the water absorption and the dielectric constant were measured under the following conditions. The results are shown in Table 1.

The water absorption was determined by using a disk-shaped cured product having a diameter of 5 cm and a thickness of 3 mm as a test piece, boiling at 100 ° C. for 20 hours, absorbing the test piece, and calculating the weight change before and after the test piece. Dielectric constant Measured according to JIS 6481 (dielectric constant and dielectric loss tangent).

[0030]

Table 1 Composition of composition Epoxy resin (A) 100 Phenol novolak 39.8 TPP 1 Physical properties of cured product Water absorption 0.97 Dielectric constant (%) 3.98

From Table 1, it is clear that the cured product of the epoxy resin of the present invention shows low water absorption and dielectric constant.

[0032]

The epoxy resin of the present invention provides a cured product excellent in water resistance and low dielectric properties as compared with the conventionally used epoxy resin, and can be used as a sealing material, an insulating material, a molding material,
It is extremely useful for a wide range of applications such as casting materials, laminate materials, paints, adhesives, resists, and the like.

Claims (5)

[Claims] (1) The following formula (1): (In the formula, n is an average value and represents a positive number of 0 to 3. 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, 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.