JPH09132623A - Novolac resin, epoxy resin, epoxy resin composition and cured product thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a novolac resin which is useful as a curing agent for epoxy resins and can give a cured product excellent in water resistance, strength, etc., by condensing a specified biphenyl with a phenol in the presence of an acid catalyst. SOLUTION: A compound represented by formula I (wherein X is a halogen, hydroxyl or a lower alkoxyl; and P is H, a halogen, a 1-8C alkyl or an aryl) is condensed with a phenol (e.g. isobutylphenol) in the presence of an acid catalyst (e.g. hydrochloric acid). The reaction temperature is desirably about 40-180 deg.C. The reaction time is desirably about 1-10hr. After the reaction, the reaction mixture is subjected to treatments such as washing with water to obtain a novolac resin represented by formula II (wherein (n) is 0-10 on the average; and R is H, a halogen, a 1-8C alkyl or an aryl). An epoxy resin composition containing the novolac resin as a curing agent is useful in the fields of laminating materials, coating materials, adhesives, resists, etc.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novolac type resin, an epoxy resin and an epoxy resin composition which give a cured product excellent in water resistance and mechanical strength.

[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 drawback that as the molecular weight increases, the toughness of a cured product obtained by curing the resin increases, but the heat resistance decreases. In addition, although a cured product obtained when a polyfunctional epoxy resin such as cresol novolak epoxy resin is mixed to compensate for a decrease in heat resistance, heat resistance is increased, but there is a disadvantage that toughness is reduced and water absorption is increased. . On the other hand, with the recent remarkable development of the electronic industry and the like, the water resistance and mechanical strength (toughness) required of the electric insulating materials used for these have become more and more severe, and the epoxy resin excellent in these properties Appearance is long awaited.

[0004]

In view of these circumstances, the present inventors have earnestly studied for an epoxy resin that gives a cured product having excellent water resistance and mechanical strength, and as a result, have found that a novolac type resin having a specific molecular structure and It has been found that the epoxy resin imparts excellent water resistance and mechanical strength 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 represents an average value and takes a value of 0 to 10. P and R are a hydrogen atom, a halogen atom and a carbon number of 1 to 8).
Represents an alkyl group or an aryl group, and individual P and R may be the same or different from each other. )
Novolak type resin represented by: (2) Formula (2)

[0008]

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(Wherein n, P and R have the same meanings as in formula (1), G represents a glycidyl group), (3) (a) epoxy resin (b) ) An epoxy resin composition containing the novolak type resin described in (1) above, (4) (a) an epoxy resin composition described in (2) above, and an epoxy resin composition containing a curing agent (b) above. 5) (a) Epoxy resin described in (2) above, (b) Epoxy resin composition containing the novolac type resin described in (1) above, (6) Above (3) containing a curing accelerator, ( 4) or the epoxy resin composition according to (5), (7) the above (3), (4) containing an inorganic filler,
(5) or (6) described epoxy resin composition, (8) a cured product obtained by curing the above (3), (4), (5), (6) or (7) epoxy resin composition Is provided.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The compound represented by the formula (1) is, for example, a compound represented by the formula (3)

[0011]

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(In the formula, X represents a halogen atom, a hydroxyl group or a lower alkoxy group. P represents the same meaning as in formula (1).)

It can be obtained by subjecting a compound represented by and a phenol to a condensation reaction in the presence of an acid catalyst.

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

In formula (3), the halogen atom is preferably a chlorine atom or a bromine atom, and the lower alkoxy group is preferably a methoxy group or an ethoxy group.

Specific examples of the phenols that can be used to obtain the compound of the formula (1) include phenols, cresol, ethylphenol,
n-propylphenol, isobutylphenol, t-
Butylphenol, octylphenol, nonylphenol, xylenol, methylbutylphenol, di-t
-Various o-, m-, p-isomers such as butylphenol,
Or cycloalkylphenol such as cyclopentylphenol, cyclohexylphenol or cyclohexylcresol, or substituted phenol such as phenylphenol, halogenated phenol such as monobromophenol or dibromophenol, or α-naphthol, β
Examples thereof include naphthols such as naphthol. These phenols may be used alone or in combination of two or more.

When the condensation reaction is carried out, the amount of phenols used is usually 0.3 to 20 mol, preferably 0.4 to 15 mol, per 1 mol of the compound represented by the formula (3).

An acid catalyst is used in the condensation reaction.
Although various kinds of acid catalysts can be used, hydrochloric acid, sulfuric acid,
Inorganic or organic acids such as p-toluenesulfonic acid and oxalic acid, Lewis acids such as boron trifluoride, anhydrous aluminum chloride and zinc chloride are preferable, and p-toluenesulfonic acid, sulfuric acid and hydrochloric acid are particularly preferable. The use amount of these acid catalysts is not particularly limited, but it is preferable to use 0.1 to 30% by weight of the compound represented by the formula (3).

The above condensation reaction can be carried out in the absence of a solvent or in the presence of an organic solvent. Specific examples of the organic solvent that can be used include methyl cellosolve, ethyl cellosolve, toluene, xylene, and methyl isobutyl ketone. The amount of the organic solvent used is preferably 50 to 300% by weight, especially 10
0 to 250% by weight is preferred. Reaction temperature is 40-180
The range of ° C is preferable, and the reaction time is preferably 1 to 10 hours. These solvents can be used alone or as a mixture of several kinds. Further, it is preferable to distill off water or alcohols generated during the reaction outside the system by using a fractionating tube or the like in order to promptly carry out the reaction.

After the completion of the reaction, washing treatment is carried out until the pH value of the washing liquid becomes 3 to 7, preferably 5 to 7. When performing a water washing treatment, 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 diethylene triamine as necessary. Various basic substances such as organic amines such as triethylenetetramine, aniline, and phenylenediamine may be used as the neutralizing agent. The washing process may be performed according to a conventional method. For example, water in which the neutralizing agent is dissolved is added to the reaction mixture, and the separation and extraction operation is repeated.

After the neutralization treatment, the solvent and unreacted substances are distilled off under reduced pressure to concentrate the product, whereby the novolak type resin of the present invention represented by the formula (1) can be obtained. .

As a method for obtaining the epoxy resin of the present invention from the compound 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 compound represented by the formula (1) obtained above and excess epihalohydrin such as epichlorohydrin or epibromhydrin, or The epoxy resin of the present invention can be obtained by reacting at a temperature of 20 to 120 ° C. for 1 to 10 hours while adding.

In the reaction for obtaining the epoxy resin 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 distilled off under reduced pressure or normal pressure, liquids are separated, water is removed, and epihalohydrin is continuously returned into the reaction system.

Further, a quaternary ammonium salt such as tetramethylammonium chloride, tetramethylammonium bromide and trimethylbenzylammonium chloride is added as a catalyst to a dissolved mixture of the compound represented by the formula (1) and epihalohydrin at 50 to 150 ° C. A solid or aqueous solution of an alkali metal hydroxide is added to the halohydrin ether compound of the compound represented by formula (1) obtained by reacting for 1 to 5 hours, and reacted at a temperature of 20 to 120 ° C. for 1 to 10 hours. A method of dehydrohalogenating (ring closure) may be used. In this case, the amount of the quaternary ammonium salt used is usually 1 to 10 g, preferably 2 to 8 g, per one hydroxyl group in the compound represented by the formula (1).

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 (1). The amount of the alkali metal hydroxide used is 0.8 to 1.5 mol, preferably 0.9 to 1.1 mol, per 1 equivalent of the hydroxyl group of the compound represented by the formula (1). 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, more preferably 4 to 15% by weight, based on the amount of epihalohydrin. When an aprotic polar solvent is used, the amount is 5 to 1 with respect to the amount of epihalohydrin.
00% by weight, more 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.,
The epihalohydrin and the solvent are removed at a pressure of 10 mmHg or less. In order to further reduce the amount of hydrolyzable halogenated epoxy resin, the obtained epoxy resin is dissolved in a solvent such as toluene or methyl isobutyl ketone, and an aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is used. In addition, further reactions can be performed to ensure ring closure. In this case, the amount of the alkali metal hydroxide used is preferably 0.01 to 0.3 with respect to 1 equivalent of the hydroxyl group of the compound represented by the formula (1) used for the epoxidation.
Mol, particularly preferably 0.05 to 0.2 mol. The reaction temperature is 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 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 will be described below. In the epoxy resin composition according to (3), (5), (6), or (7), the novolak resin of the present invention acts as a curing agent for the epoxy resin. In this case, the novolak resin of the present invention is used alone. Alternatively, it can be used in combination with another curing agent. When used in combination, the proportion of the novolak resin of the present invention in the total curing agent is preferably at least 30% by weight, particularly preferably at least 40% by weight.

Examples of other curing agents used in combination with the novolak type resin of the present invention include amine compounds, acid anhydride compounds, amide compounds and phenol compounds. 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. Mellitic acid, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride,
Hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, phenol-novolak, and modified products thereof,
Examples thereof include, but are not limited to, imidazole, BF ₃ -amine complex, guanidine derivative and the like. These may be used alone or in combination of two or more.

In the epoxy resin composition described in (4), (5), (6) and (7), the epoxy resin of the present invention can be used alone or in combination with other epoxy resins. When used together, the proportion of the epoxy resin of the present invention in the total epoxy resin is preferably at least 30% by weight, particularly preferably at least 40% by weight.

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

In the epoxy resin composition of the above (3), (6) and (7), when the novolac type resin of the present invention is used as a curing agent, the other epoxy resin or the epoxy of the present invention is used as the epoxy resin. Resin can be used.

When the epoxy resin of the present invention is used as the epoxy resin in the epoxy resin composition of the above (4), (6) and (7), the other curing agent or the novolak of the present invention is used as the curing agent. Mold resin can be used.

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. 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 the epoxy resin as required.

The epoxy resin composition 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 amount of the inorganic filler occupying 0 to 90% by weight in the epoxy resin composition of the present invention is used. Furthermore, 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 is obtained by uniformly mixing the components. The epoxy resin composition of the present invention containing the epoxy resin of the present invention, the curing agent and, if necessary, a curing accelerator can be easily cured 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, an extruder, a kneader,
The epoxy resin composition of the present invention is sufficiently mixed by using a roll or the like until it becomes uniform, and 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 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 the base material with heat and drying can also be hot-press molded to obtain a cured product. The solvent at this time is usually 10 to 70% by weight, preferably 1% in the mixture of the epoxy resin composition of the present invention and the solvent.
An amount occupying 5 to 65% by weight is used.

Since the cured product of the present invention thus obtained is excellent in heat resistance, water resistance and mechanical strength, it can be used in a wide range of fields where heat resistance, water resistance and high mechanical strength are required. 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.

[0041]

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

Example 1 A flask equipped with a thermometer, a dropping funnel, a cooling tube, a fractionating tube and a stirrer was charged with the following formula (4).

[0043]

[Chemical 6]

121 parts of the compound represented by: and phenol 1
13 parts were charged and stirred at room temperature while blowing nitrogen. 0.5 parts of p-toluenesulfonic acid (monohydrate) was slowly added while paying attention to heat generation so that the liquid temperature did not exceed 50 ° C. After that, heat to 120 ° C. in an oil bath, extract the produced methanol using a fractionating tube, and then add 5 more.
Allowed to react for hours. After completion of the reaction, 500 ml of methyl isobutyl ketone was further added, and the mixture was transferred to a separating funnel and washed with water. After washing with water until the washing water shows neutrality, the solvent is removed from the organic layer under heating and reduced pressure, and the following formula (5)

[0045]

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164 parts of the novolak type resin (A) of the present invention represented by The softening point of the obtained novolac type resin was 82.0 ° C., and the hydroxyl group equivalent was 221 g / eq.

Example 2 A flask equipped with a thermometer, a cooling tube and a stirrer was charged with 155 parts of the novolac resin (A) obtained in Example 1, 389 parts of epichlorohydrin and 97 parts of dimethyl sulfoxide while purging with nitrogen gas. Dissolved. 4 more
Flake-shaped sodium hydroxide (Purity 99
%) (28.3 parts) was added portionwise over 90 minutes, and then the mixture was further reacted at 45 ° C. for 2 hours and at 70 ° C. for 1 hour. After completion of the reaction, dimethylsulfoxide and epichlorohydrin were distilled off under heating and reduced pressure at 130 ° C., and 388 parts of methyl isobutyl ketone was added and dissolved in the residue.

Further, this methyl isobutyl ketone solution was heated to 70 ° C. to obtain a 30 wt% sodium hydroxide aqueous solution 7
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.

[0049]

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186 parts of the epoxy resin (B) of the present invention represented by the formula (wherein G represents a glycidyl group) were obtained. The obtained epoxy resin had a softening point of 72.5 ° C. and an epoxy equivalent of 289 g / eq.

Example 3 The reaction was carried out in the same manner as in Example 1 except that 216 parts of α-naphthol was used instead of phenol, and the following formula (7) was used.

[0052]

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168 parts of the novolac type resin (C) of the present invention represented by The hydroxyl equivalent of the obtained novolac type resin was 236 g / eq and the softening point was 91.6 ° C.

Example 4 An epoxidation reaction was carried out in the same manner as in Example 2 except that 165 parts of the novolac type resin (C) obtained in Example 3 was used, and the following formula (8) was used.

[0055]

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196 parts of the epoxy resin (D) of the present invention represented by the formula (G represents a glycidyl group) were obtained. The obtained epoxy resin had a softening point of 85.3 ° C. and an epoxy equivalent of 308 g / eq.

Examples 5 and 6 Orthocresol novolac type epoxy resin EOCN1
020 (epoxy equivalent 200 g / eq, manufactured by Nippon Kayaku), the novolac resins (A), (C) obtained above,
Triphenylphosphine (TPP) was used as a curing accelerator and blended in the composition shown in the composition column of the blend in Table 1,
Knead with rolls at 70 ℃ for 15 minutes, 150 ℃, molding pressure 5
Transfer molding was performed at 0 kg / cm ² for 180 seconds, followed by curing at 160 ° C. for 2 hours and then at 180 ° C. for 8 hours to prepare a test piece, and the water absorption rate and Izod impact test value were measured. Table 1 shows the results. The measurement conditions of the water absorption rate and the Izod impact test value are as follows. Also, in the table, the numerical values in the column of the composition of the blend indicate parts by weight.

Water Absorption Rate Test Piece (Cured Product): Diameter 50 mm, Thickness 3 mm Disk Weight increase rate (%) after boiling in 100 ° C. water for 24 hours Izod impact test value (KJ / m ² ) According to JIS K-6911 Compliant and measured

[0059]

Table 1 Table 1 Example 5 Example 6 Composition of formulation EOCN1020 100 100 Novolak type resin (A) 111 Novolak type resin (C) 118 TPP 1 1 Physical properties of cured product 0.90 0.75 Izod impact test value 24.9 22.1

Examples 7 to 9 Phenol novolac (softening point 83 ° C., hydroxyl group equivalent 1) as a curing agent for the obtained epoxy resins (B) and (D)
06 g / eq), a novolac type resin (A), and triphenylphosphine (TPP) as a curing accelerator,
Formulated in the composition column of the composition of Table 2 and mixed at 70 ° C
Kneading with a roll for 15 minutes at 150 ℃, molding pressure 50kg
Transfer molding at 180 / cm ² for 180 seconds, then 1
A test piece was prepared by curing at 60 ° C. for 2 hours and further at 180 ° C. for 8 hours, and the water absorption and Izod impact test values were measured. Table 2 shows the results. The conditions for measuring the water absorption rate and the Izod impact test value are the same as above. Also, in the table,
Numerical values in the column of composition of formulation indicate parts by weight.

[0061]

[Table 2] Table 7 Example 7 Example 8 Example 9 Composition of compound Epoxy resin (B) 100 100 Epoxy resin (D) 100 Phenol Novolac 37 34 Novolac type resin (A) 76 TPP 1 1 1 Cured product Physical properties Water absorption 0.82 0.67 0.60 Izod impact test value 28.2 26.3 30.2

From Tables 1 and 2, it is clear that the cured products of the novolac type resin and the epoxy resin of the present invention show low water absorption and high mechanical strength.

[0063]

INDUSTRIAL APPLICABILITY The novolac type resin and epoxy resin of the present invention can give a cured product excellent in water resistance and mechanical strength, and can be used in a wide range of molding materials, casting materials, laminating materials, paints, adhesives, resists, Very useful for the purpose.

Claims (8)

[Claims] (1) Formula (1) (In the formula, n represents an average value and takes a value of 0 to 10. P, R
Represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 8 carbon atoms, or an aryl group, and each P and R may be the same or different. ) Novolak type resin represented by. (2) Formula (2) (In the formula, n, P, and R represent the same meanings as in formula (1). G represents a glycidyl group). 3. An epoxy resin composition comprising: (a) an epoxy resin; and (b) the novolak 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. The epoxy resin composition according to claim 3, which contains an inorganic filler. 8. A cured product obtained by curing the epoxy resin composition according to claim 3, 4, 5, 6 or 7.