JPH08193110A - Novolak resin, epoxy resin, epoxy resin composition, and cured article obtained therefrom - Google Patents

Abstract

PURPOSE: To obtain an epoxy resin which gives a cured article excellent in heat resistance, water resistance, and dielectric properties by epoxidizing a novolak resin having a specific molecular structure. CONSTITUTION: A novolak resin (a) represented by formula I (wherein n is 1-10 and t-Bu is tert-butyl) is epoxidized to obtain an epoxy resin (b) represented by formula II (wherein n and t-Bu are as defined above and G is glycidyl). The resin (a) can be obtained, for example, by reacting a methyl-t-butylphenol (preferably 3-methyl-6-t-butylphenol, represented by formula III) with formalin in the presence of an acid catalyst. The resin (b) can be obtained by reacting the resin (a) with an epihalohydrin in the presence of an alkali metal hydroxide. A composition containing the resin (b) gives a cured article having a higher Tg , a lower water absorption, and a lower permittivity than the cured compositions formed from known epoxy resin compositions. The composition is useful in a wide range of applications including molding, casting, and laminating materials, a paint, and an adhesive.

Description

Detailed Description of the Invention

[0001]

The present invention has excellent heat resistance and water resistance,
Moreover, a novolac resin that gives a cured product with a low dielectric constant,
The present invention relates to an epoxy resin and an epoxy resin composition.

[0002]

2. Description of the Related Art Heretofore, in the field of electric / electronic parts, particularly IC sealants, resin compositions containing epoxy resin, phenol novolac resin and curing accelerator as main components have been widely used. Also, as the material for the printed wiring board,
A combination of bisphenol type epoxy resin and dicyandiamide is mainly used. The high density and high integration of ICs in recent years have made it necessary for sealing agents to have high heat resistance and low water absorption. In particular, the harsh condition of immersion in a solder bath in high-density mounting of ICs has further strengthened the demand for high heat resistance and low water absorption of cured products. Further, as the number of printed wiring boards is increased, the low dielectric property of resin is being demanded mainly for the purpose of improving the signal speed.

[0003]

However, in the conventional composition, the cresol novolac type epoxy resin generally used as an epoxy resin has a high heat resistance but has a drawback that it is inferior in water absorption. On the other hand, the phenol novolac resin generally used as a curing agent is still inadequate in terms of heat resistance, and does not give satisfactory results under increasingly severe conditions. Further, addition of a thermoplastic resin having a low dielectric constant is well known to meet the demand for a low dielectric constant, but this method has been pointed out to have a drawback that heat resistance and adhesiveness of an epoxy resin are impaired. Therefore, development of a resin that gives a cured product having heat resistance, low water absorption and low dielectric constant has been awaited.

[0004]

In view of these circumstances, the present inventors have earnestly studied for an epoxy resin that provides a cured product having excellent heat resistance and water resistance and a low dielectric constant, and as a result, has found that a specific molecular structure is obtained. A novolac type resin having and an epoxy resin obtained by epoxidizing the same,
The inventors have found that the cured product exhibits excellent heat resistance, water resistance and dielectric constant properties, and completed the present invention.

That is, the present invention is based on the equation (1)

[0006]

Embedded image

(In the formula, n represents an average value and represents a value of 1 to 10. t-Bu represents a tertiary butyl group.), A novolac type resin, (2) Formula (2)

[0008]

[Chemical 4]

(In the formula, n represents an average value and represents a value of 1 to 10. t-Bu represents a tertiary butyl group and G represents a glycidyl group.) (3) (A) Epoxy resin (b) Epoxy resin composition containing the novolac type resin described in (1) above, (4) (a) Epoxy resin described in (2) above, and (b) a curing agent. (5) (a) Epoxy resin described in (2) above (b) Epoxy resin composition containing the novolac type resin described in (1) above, (6) Containing a curing accelerator (3) The epoxy resin composition according to (3), (4), (5) or (6) above, which is cured by curing the epoxy resin composition according to (3), (4) or (5) above. The following cured product is provided.

The compound represented by the formula (1) can be obtained, for example, by reacting methyl-t-butylphenol and formalin in the presence of an acid catalyst.

The compound represented by the formula (2) can be obtained by reacting the compound represented by the formula (1) with epihalohydrin in the presence of an alkali metal hydroxide.

The form of formalin used here may be an aqueous solution or paraformaldehyde. The addition amount of formalin is preferably 0.05 to 0.95 mol, particularly 0.1 to 0.1 mol, relative to 1 mol of methyl-t-butylphenol.
0.9 mol is preferred. A solvent may or may not be used in the reaction, but when a solvent is used, methyl isobutyl ketone, toluene, xylene and the like can be mentioned as specific examples. The reaction temperature is preferably 50 to 150 ° C, particularly preferably 60 to 140 ° C. At the time of the reaction, it is preferable that the water contained in the formalin aqueous solution and the water produced by the reaction be distilled out of the reaction mixture by azeotropy, the water is removed, and the solvent is returned to the reaction mixture for rapid reaction. The reaction time is usually 1 to 15 hours, preferably 2
~ 10 hours.

In the above condensation reaction, it is preferable to use an acid catalyst, and various kinds of acid catalysts can be used, but organic or inorganic acids such as hydrochloric acid, sulfuric acid, p-toluenesulfonic acid and oxalic acid, and boron trifluoride. Lewis acids such as anhydrous aluminum chloride and zinc chloride are preferable, and p-toluenesulfonic acid, sulfuric acid and hydrochloric acid are particularly preferable. The amount of these acid catalysts used is not particularly limited, but methyl-t-
Usually 0.1 to 5 per 100 parts by weight of butylphenol
It is 0 part by weight, preferably 0.5 to 20 parts by weight.

After completion of the reaction, neutralization or washing is carried out to adjust the pH value of the product to 3 to 7, preferably 5 to 7. When washing with water, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkaline earth metal hydroxides such as calcium hydroxide and magnesium hydroxide, ammonia, sodium dihydrogen phosphate and diethylenetriamine and trihydrate. Various basic substances such as organic amines such as ethylene tetramine, aniline and phenylenediamine may be used as the neutralizing agent for treatment. In the case of washing with water, it may be carried out according to a conventional method. For example, water in which the above neutralizing agent is dissolved is added to the reaction product, and the liquid separation and extraction operation is repeated.

After neutralization or washing with water, the unreacted methyl-t-butylphenol and the solvent are distilled off under reduced pressure to concentrate the product to obtain the novolak type resin represented by the formula (1). You can get it.

In the reaction described above, methyl-t-
It is particularly preferable to use 3-methyl-6-t-butyl-phenol represented by the following formula (3) as butylphenol. In this case, the novolac resin of the present invention represented by the following formula (4) and the epoxy resin of the present invention represented by the following formula (5) are obtained.

[0017]

Embedded image

(In the formula, t-Bu represents a tertiary butyl group.)

[0019]

[Chemical 6]

[0020]

[Chemical 7]

(In formulas (4) and (5), t-Bu, G, n
Represents the same meaning as in formulas (1) and (2). )

As a method for obtaining the epoxy resin of the present invention represented by the formula (2) from the novolak type resin represented by the formula (1), 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 novolak type resin and an excess epihalohydrin such as epichlorohydrin or epibromhydrin, or while addition is performed at 20 to 120 ° C. 0 at temperature.
The epoxy resin of the present invention can be obtained by reacting for 5 to 10 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 which case the aqueous solution of the alkali metal hydroxide is continuously added to the reaction mixture. A method may be used in which water and epihalohydrin are continuously flown out under reduced pressure or normal pressure, and liquid separation is performed to remove water and epihalohydrin is continuously returned to the reaction mixture.

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 novolak type resin represented by the formula (1) and epihalohydrin, and the mixture is added at 50 to 150. ℃
To the halohydrin etherified product of the compound of formula (1) obtained by reacting for 0.5 to 5 hours with a solid or aqueous solution of an alkali metal hydroxide, and again at a temperature of 20 to 120 ° C. for 0.5 to 10 The epoxy resin of the present invention can also be obtained by reacting for a period of time and dehydrohalogenating (ring closure). In this case, the amount of the quaternary ammonium salt used is usually 0.001 to 0.2 mol, preferably 0.05 to 0.1 mol, relative to 1 equivalent of the hydroxyl group of the compound of formula (1).

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 of formula (1). The amount of the alkali metal hydroxide used is usually 0.8 to 15 mol, preferably 0.1 to 1 equivalent of the hydroxyl group of the compound of the formula (1).
It is 9 to 11 mol. Furthermore, in order to make the reaction proceed smoothly, in addition to alcohols such as methanol and ethanol,
It is preferable to carry out the reaction by adding an aprotic polar solvent such as dimethyl sulfone or dimethyl sulfoxide.

When alcohol is used, its amount is usually 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 usually 5 relative to the amount of epihalohydrin.
-100% by weight, preferably 10-90% by weight.

After washing these reaction products of the epoxidation reaction with or without washing with water, under heating and reduced pressure at 150 to 250 ° C.
Epihalohydrin and other added solvents are removed at a pressure of 10 mmHg or less. Further, in order to obtain an epoxy resin having a smaller amount of hydrolyzable halogen, the obtained epoxy resin is dissolved again in a solvent such as toluene or methyl isobutyl ketone, and an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is added. It is also possible to add an aqueous solution and carry out further reaction to ensure ring closure. In this case, the amount of the alkali metal hydroxide used is usually 0.01 to 0.3 mol, preferably 0.05 to 0.2 mol, relative to 1 equivalent of the hydroxyl group of the compound of the formula (1) as a raw material. Reaction temperature is 50-1
The reaction time is usually 0.5 to 2 hours at 20 ° C. After completion of the reaction, the produced 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 an epoxy resin represented by the formula (2) of the present invention. To be

The epoxy resin composition of the present invention will be described below. In the epoxy resin composition described in (3) or (5), other curing agent can be used in combination with the novolac resin of the present invention. When used in combination, the proportion of the novolac resin of the present invention in the total curing agent is preferably 30% by weight or more, and particularly preferably 40% by weight or more.

Other curing agents that can be used in combination with the novolak type resin of the present invention include, for example, amine compounds, acid anhydride compounds, amide compounds and phenol compounds. Specific examples include diaminodiphenylmethane, diethylenetriamine, triethylenetetramine,
Polyamide resin synthesized from diaminodiphenylsulfone, isophoronediamine, dicyandiamide, linolenic acid dimer and ethylenediamine, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydro Phthalic anhydride, methyl nadic acid anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, pheno-
Lunovolac and modified products thereof, imidazole, B
Examples thereof include, but are not limited to, F ₃ -amine complex and guanidine derivative. These may be used alone or in combination of two or more.

In the epoxy resin composition described in (4) or (5), other epoxy resin can be used in combination with the epoxy resin of the present invention. When used in combination, the proportion of the epoxy resin of the present invention in the total epoxy resin is preferably 30% by weight or more, and particularly preferably 40% by weight or more.

Other epoxy resins which can be used in combination with the epoxy resin of the present invention include novolac type epoxy resins other than the epoxy resin of the present invention, bisphenol A type epoxy resins, bisphenol F type epoxy resins, biphenyl type epoxy resins and the like. However, these may be used alone or in combination of two or more.

In the epoxy resin composition described in (3) above, when the novolac type resin of the present invention is used as the curing agent, the other epoxy resin described above or the epoxy resin of the present invention can be used as the epoxy resin.

In the epoxy resin composition described in (4) above, when the epoxy resin of the present invention is used as the epoxy resin, the other curing agent described above or the novolak type resin of the present invention can be used as the curing agent. .

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 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 the curing accelerator that can be used include imidazoles such as 2-methylimidazole, 2-ethylimidazole, and 2-ethyl-4-methylimidazole, 2- (dimethylaminomethyl) phenol,
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 is obtained by uniformly mixing the components. The epoxy resin composition of the present invention containing the epoxy resin of the present invention, a curing agent, and optionally 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, if necessary a curing accelerator,
Extruder with filler material and other compounding agents if necessary,
The epoxy resin composition of the present invention is obtained by sufficiently mixing with a kneader, a roll, etc. until it becomes uniform, and the epoxy resin composition is melted and then cast or molded using a transfer molding machine or the like. Then, the cured product of the present invention can be obtained by further 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 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 to 70% by weight, preferably 15 to 65% by weight, based on the total weight of the epoxy resin composition of the present invention and the diluent solvent.

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

[0040]

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, a separator and a stirrer was charged with 197 parts of 3-methyl-6-t-butylphenol, 100 parts of methyl isobutyl ketone, and p.
-Toluenesulfonic acid 0.6 part was prepared, and a 35% formalin aqueous solution 62 parts was dripped over 1 hour, stirring at 70 degreeC. Further, the reaction is carried out at 70 ° C. for 1 hour under stirring, then the temperature is raised to 110 ° C., water distilled by azeotropic distillation is separated, removed outside the reaction mixture, and methyl isobutyl ketone is returned to the reaction mixture. The reaction was carried out for 2 hours.

Then, 300 parts of methyl isobutyl ketone was added, 10 parts of a 20% sodium dihydrogen phosphate aqueous solution was added, and the mixture was washed 3 times with water, and then heated under reduced pressure to remove excess 3-methyl-6-t-butylphenol and solvent. Was removed to obtain 169 parts of the novolac resin (A) of the present invention represented by the above formula (4). The softening point of the obtained novolac type resin is 88.5 ° C., the hydroxyl group equivalent is 172 g / eq, n
= 1.9 (average value).

Example 2 and Comparative Example 1 An o-cresol novolac type epoxy resin (EOCN1020, manufactured by Nippon Kayaku Co., Ltd., softening point 65.1 ° C., epoxy equivalent 200 g / eq) as an epoxy resin, and a curing agent were obtained. Novolak type resin (A), a phenol novolak resin (softening point 80.2 ° C., hydroxyl group equivalent 106 g / eq) for comparison, and triphenylphosphine (TPP) as a curing accelerator, and blended in the composition shown in Table 1. ,
Knead with rolls at 70 ℃ for 15 minutes, 150 ℃, molding pressure 5
Transfer molding at 0 kg / cm ² for 180 seconds,
Then, it was cured at 160 ° C. for 2 hours and further at 180 ° C. for 8 hours to prepare a test piece (cured product of the present invention), and the glass transition point, water absorption and dielectric constant 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.

Glass transition temperature thermomechanical measuring device (TMA): TM- manufactured by Vacuum Riko Co., Ltd.
7000 Temperature rising rate: 2 ° C / min Water absorption rate Test piece (cured product): Diameter 50 mm Thickness 3 mm Disc Weight increase rate (%) after boiling in 100 ° C water for 24 hours Dielectric constant JIS 6481 (dielectric constant and dielectric Tangent).

[0045]

[Table 1] Table 1 Example 2 Comparative example 1 Composition of formulation EOCN1020 100 100 Novolac type resin (A) 86.0 Phenol novolac 53.0 TPP 1 1 Physical properties of cured product Glass transition point (° C) 165 153 Water absorption rate (%) 0.97 1.30 Dielectric constant 3.95 4.50

Example 3 A novolac type resin (A) 172 was applied to a flask equipped with a thermometer, a cooling tube and a stirrer while purging with nitrogen gas.
Parts, 370 parts of epichlorohydrin, and 93 parts of dimethyl sulfoxide were charged and dissolved. Further, it is heated to 50 ° C. and 90.4 parts of 40.4 parts of flaky sodium hydroxide (purity 99%) are added.
Add in portions over 0 minutes and then at 60 ° C for 2 hours, 7
The reaction was carried out at 0 ° C for 1 hour. After completion of the reaction, dimethylsulfoxide and epichlorohydrin were distilled off under heating and reduced pressure at 130 ° C., and 460 parts of methyl isobutyl ketone was added and dissolved in the residue.

Further, this methyl isobutyl ketone solution was heated to 70 ° C. and 30% by weight of sodium hydroxide aqueous solution 1
After adding 0 parts and reacting for 1 hour, washing with water was repeated 3 times to make the pH of the product neutral. Further, the aqueous layer was separated and removed, and methyl isobutyl ketone was distilled off from the oil layer under heating and reduced pressure using a rotary evaporator to obtain 216 parts of the epoxy resin (B) of the present invention represented by the above formula (5). The obtained epoxy resin had a softening point of 63.2 ° C. and an epoxy equivalent of 240 g / eq.

Example 4, Comparative Example 2 The obtained epoxy resin (B), for comparison, o-cresol novolac type epoxy resin (EOCN1020, manufactured by Nippon Kayaku Co., Ltd., softening point 65.1 ° C., epoxy equivalent 200 g)
/ Eq), phenol novolak (hydroxyl group equivalent 106 g / eq, softening point 80.2 ° C.) as a curing agent, and triphenylphosphine (TPP) as a curing accelerator.
A test piece (cured product of the present invention) was prepared in the same manner as in Example 1, and the glass transition point, water absorption rate and dielectric constant were measured. Table 2 shows the results. The glass transition point,
The conditions for measuring the water absorption rate and the dielectric constant are as described above. Further, in the table, the numerical value in the column of composition of formulation shows parts by weight.

[0049]

Table 2 Example 4 Comparative Example 2 Composition of the compound Epoxy resin (B) 100 EOCN1020 100 (epoxy equivalent (g / eq)) 240 200 Phenol novolac 44.2 53.0 TPP 1 1 Physical properties of cured product Glass transition point ( ℃) 174 153 Water absorption (%) 1.10 1.05 Dielectric constant 3.91 4.50

Example 5, Comparative Example 3 Epoxy resin (B), novolak type resin (A) obtained as a curing agent therefor, and o-cresol novolac type epoxy resin (EOCN1020, Nippon Kayaku Co., Ltd.) for comparison.
Made, softening point 65.1 ° C, epoxy equivalent 200g / e
q), its curing agent is phenol novolac (hydroxyl group equivalent: 106 g / eq, softening point: 80.2 ° C.), and triphenylphosphine (TPP) is used as a curing accelerator.
Compounded in a composition as shown in, and kneaded with a roll at 70 ° C. for 15 minutes, transfer molded at 150 ° C. and a molding pressure of 50 kg / cm ² for 180 seconds, and then cured at 160 ° C. for 2 hours and then at 180 ° C. for 8 hours. A test piece (cured product of the present invention) was prepared by measuring the glass transition point, water absorption and mechanical strength. The results are shown in Table 3. The conditions for measuring the glass transition point, the water absorption rate and the bending strength are as described above. Further, in the table, the numerical value in the column of composition of formulation shows parts by weight.

[0051]

Table 3 Table 3 Example 5 Comparative Example 3 Composition of the compound Epoxy resin (B) 100 EOCN1020 100 (Epoxy equivalent (g / eq)) 216 200 Novolac type resin (A) 67.1 Phenol novolac 53.0 TPP 1 1 cured product Physical properties of glass transition point (℃) 186 153 Water absorption rate (%) 1.23 1.30 Dielectric constant 3.72 4.50

From Tables 1 to 3, the cured product of the epoxy resin composition using the novolac type resin and / or the epoxy resin of the present invention is better than the cured product of the known epoxy resin composition.
It showed a high glass transition point, low water absorption and low dielectric constant.

[0053]

INDUSTRIAL APPLICABILITY The novolac type resin and / or epoxy resin of the present invention can give a cured product having excellent heat resistance, water resistance and dielectric properties, and can be used as a molding material, a casting material, a laminating material, a paint, an adhesive. Very useful for a wide range of applications such as resists.

Claims (7)

[Claims] 1. A formula (1): (In formula, n represents an average value and shows the value of 1-10. T-B
u represents a tertiary butyl group. ) Novolak type resin represented by. 2. Formula (2): (In formula, n represents an average value and shows the value of 1-10. T-B
u represents a tertiary butyl group and G represents a glycidyl group. ) Epoxy resin represented by. 3. An epoxy resin composition comprising (a) an epoxy resin and (b) the novolac type resin according to claim 1. 4. An epoxy resin composition comprising (a) the epoxy resin according to claim 2 and (b) a curing agent. 5. An epoxy resin composition comprising (a) the epoxy resin according to claim 2 and (b) the novolac type resin according to claim 1. 6. The epoxy resin composition according to claim 3, 4 or 5 containing a curing accelerator. 7. A cured product obtained by curing the epoxy resin composition according to claim 3, 4, 5 or 6.