JPH09268219A - Novolak type resin, epoxy resin, epoxy resin composition and its cured material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject resin capable of providing a curd material excellent in water resistance and mechanical strength, useful as a molding material, a casting material, a coating material, an adhesive, having a specific molecular structure and a molecular weight distribution. SOLUTION: This novolak resin is shown by formula I ((n) is an average value and is a value of 0-10; P and R are each H, a halogen, a 1-8C alkyl or an aryl) and has <=70% area ratio of a rate in which (n) is 0 in formula I in GPC(gel permeation chromatography) analysis. The compound of formula I is obtained, for example, by condensing a compound of formula II (X is a halogen, hydroxyl group or a lower alkoxy) with a phenol in the presence of an acid catalyst. The compound of formula I is reacted with an epihalohydrin in the presence of an alkali metal hydroxide to give an epoxy resin of formula III (G is glycidyl). The epoxy resin has <=70% area ratio of a rate in which (n) is 0 in formula II is GPC analysis.

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 for the electric insulating materials used for these have become more and more severe, and a curing agent excellent in these properties and The advent of epoxy resins has been awaited.

As an example of an epoxy resin and a curing agent therefor satisfying such requirements, JP-A-5-117350 exemplifies a novolac type resin (curing agent) having a biphenyl-phenol skeleton and an epoxy resin. However, in the case of a novolac type resin having such a structure, if the proportion of low molecular weight molecules contained in the resin is high, the obtained resin tends to be crystals with a high melting point. When the novolac type resin becomes a crystal having a high melting point, it is difficult to take it out of the reactor after purification. Further, in order to use it as a curing agent for epoxy resin, it is necessary to raise the temperature during kneading to a very high level, which may impair workability.

[0005]

In view of these circumstances, the present inventors have provided a cured product having excellent water resistance and mechanical strength,
Moreover, as a result of earnest research for a curing agent and an epoxy resin having excellent workability, it was found that a novolac type resin and an epoxy resin having a specific molecular structure and a molecular weight distribution satisfy the above-mentioned characteristics. Came to complete.

That is, the present invention uses the formula (1)

[0007]

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(In the formula (1), n represents an average value and is 0-10.
Take the value of P and R each represent 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. A novolac type resin represented by the formula (2), wherein the proportion of n = 0 in the formula (1) in the GPC (gel permeation chromatography) analysis is 70% or less in terms of area ratio; (2)

[0009]

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An epoxy resin represented by the formula (2) wherein n, P and R have the same meanings as in the formula (1) and G represents a glycidyl group. An epoxy resin in which the proportion of n = 0 in the formula (2) is 70% or less in area ratio.

(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 (b) (5) (a) Epoxy resin described in (2) above (b) Epoxy resin composition containing the novolac type resin described in (1) above, (6) ) The epoxy resin composition according to any one of (3), (4) or (5) containing a curing accelerator, (7) the above (3), (4) containing an inorganic filler.
The epoxy resin composition according to any one of (5) or (6), (8) The above-mentioned (3), (4), (5), (6) or (7). A cured product obtained by curing the above epoxy resin composition is provided.

[0012]

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

[0013]

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

When the above condensation reaction is carried out, the amount of the phenols used is usually 1.1 to 10 mol, preferably 1.2 to 8 mol, and particularly preferably 1 mol of the compound represented by the formula (3). It is 1.2 to 5 mol. When the amount of the phenols used is large, when the residual phenols are distilled off, the resulting condensate may be crystals with a high melting point and may not be taken out from the concentrator. The molecular weight distribution of the condensate effective to prevent this crystallization problem is such that the proportion of n = 0 in the formula (1) is 70% or less of the total area when the molecular weight distribution is measured using GPC. The content is preferably 65% or less.

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 amount of these acid catalysts used is not particularly limited, but is usually 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 usually 50 to 300% by weight, preferably 100, with respect to the total weight of the raw materials charged.
~ 250% by weight. The reaction temperature is usually 40 to 180
The reaction temperature is usually 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 completion of the reaction, a 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 novolac 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 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 (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 of formula (1) obtained by reacting for 1 to 5 hours, and the mixture is reacted at 20 to 120 ° C. for 1 to 10 hours to dehydrohalogenate ( A method of 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, relative to 1 hydroxyl group in 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 represented by the formula (1). The amount of the alkali metal hydroxide used is usually 0.8 to 1.5 mol, preferably 0.9 to 1.1 mol, relative to 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 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 parts by weight based on the amount of epihalohydrin.
-100% by weight, preferably 10-90% by weight.

After washing the reaction products of these epoxidation reactions 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 usually 0.01 to 0.3 mol, preferably 0.05 to 0.2 mol, per 1 equivalent of the hydroxyl group of the compound of the formula (1) used for the epoxidation. is there. The reaction temperature is usually 50-
The reaction time is usually 0.5 to 2 hours at 120 ° C.

After the 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.

Other curing agents 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 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 imidazole, BF ₃ -amine complex, and guanidine derivative, but are not particularly limited as long as they are known as curing agents for epoxy resins. These curing agents 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.

Specific examples of other epoxy resins that 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. They may be used alone or in combination of two or more.

In the epoxy resin compositions of (3), (6) and (7), when the novolac type resin of the present invention is used as a curing agent, the other epoxy resin of the present invention 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.

In the epoxy resin composition of the present invention, the amount of the curing agent used 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 the above-mentioned curing agent is used, a curing accelerator may be used together. 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 inorganic filler is used in an amount of 0 to 90% by weight in the epoxy resin composition of the present invention, if necessary. 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 can be obtained by uniformly mixing the respective components in 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, the epoxy resin of the present invention and a curing agent, if necessary, a curing accelerator and an inorganic filler, and various compounding agents are used, if necessary, by using an extruder, a kneader, a roll, etc. The epoxy resin composition of the present invention is obtained by mixing, and the epoxy resin composition is melted and then molded using a casting or transfer molding machine, and further at 80 to 200 ° C. for 2-1.
The cured product of the present invention can be obtained by heating for 0 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.

The thus obtained cured product of the present invention is excellent in heat resistance, water resistance and mechanical strength, so that 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.

[0043]

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. The GPC analyzer, water absorption, and Izod impact test values were measured under the following conditions.

GPC analyzer Liquid transfer pump: L-6000 (manufactured by Hitachi Ltd.) UV detector: L-4000 (manufactured by Hitachi Ltd.) Measured by absorbance at 254 nm Column: KF-803 (1 piece) + KF-802.5 (2) Book) + KF-802 (1) (Showa Denko) Solvent: Tetrahydrofuran (THF) Water absorption Test piece (cured product): Diameter 50 mm Thickness 3 mm Disc Weight increase rate after boiling in 100 ° C water for 24 hours ( %) Izod impact test value (KJ / m ² ) Measured according to JIS K-6911

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

[0046]

[Chemical 6]

107 parts of a compound represented by: and phenol 1
13 parts were charged, and the mixture was stirred and dissolved 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. Then heat to 120 ° C in an oil bath,
After extracting the produced water using a fractionating pipe, 120 more
The reaction was carried out at 0 ° C for 5 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)

[0048]

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156 parts of the novolak type resin (A) of the present invention represented by the formula (n represents an integer) were obtained. The obtained novolac-type resin had a softening point of 85.3 ° C., a hydroxyl group equivalent of 203 g / eq, and a proportion of n = 0 by GPC of 23% in area%.

Example 2 A flask equipped with a thermometer, a cooling tube, and a stirrer was charged with 102 parts of the novolak resin (A) obtained in Example 1, 185 parts of epichlorohydrin, and 46 parts of dimethyl sulfoxide while carrying out nitrogen gas purging. Dissolved. 4 more
Flake-shaped sodium hydroxide (Purity 99
%) 20.2 parts were 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, the mixture was heated to 130 ° C., dimethylsulfoxide and epichlorohydrin were distilled off under reduced pressure, and 259 parts of methyl isobutyl ketone was added and dissolved in the residue.

Further, this methyl isobutyl ketone solution is heated to 70 ° C. and a 30% by weight aqueous solution of sodium hydroxide 5
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.

[0052]

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(In the formula, n represents an integer and G represents a glycidyl group.) Epoxy resin (B) 1 of the present invention
23 parts were obtained. The softening point of the obtained epoxy resin is 70.
5 ° C., epoxy equivalent is 277 g / eq, n by GPC
The ratio of = 0 was 19% in area%.

Example 3 The same reaction as in Example 1 was carried out except that the amount of phenol used was 141 parts to obtain 143 parts of the novolac type resin (C) represented by the above formula (5). . The hydroxyl equivalent of the obtained novolac type epoxy resin is 198 g / e.
q, the softening point was 75.5 ° C., and the proportion of n = 0 by GPC was 41% in area%.

Example 4 An epoxy resin of the present invention represented by the above formula (6) was prepared by carrying out an epoxidation reaction in the same manner as in Example 2 except that 99 parts of the novolak type resin (C) obtained in Example 3 was used. Resin (D) 122
Got a part. The softening point of the obtained epoxy resin is 66.7.
C, epoxy equivalent is 271 g / eq, n = by GPC
The ratio of 0 was 35% in area%.

Examples 5 to 7 For the epoxy resins (B) and (D) obtained above, phenol novolac (having a hydroxyl equivalent of 106 g) was used as a curing agent.
/ Eq, softening point 80.3 ° C.) and novolac type resin (A), triphenylphosphine (T
PP) and compounded in the composition shown in the column of the composition of Table 1 and kneaded with a roll at 70 ° C. for 15 minutes, and transfer molded at 150 ° C. at a molding pressure of 50 kg / cm ² for 180 seconds. A test piece was prepared by curing at 160 ° C. for 2 hours and further at 180 ° C. for 8 hours, and the water absorption rate and Izod impact test value were measured. The results are shown in the column of physical properties of the cured product in Table 1. Also, in the table, the numerical values in the column of the composition of the blend indicate parts by weight.

[0057]

Table 1 Table 5 Example 5 Example 6 Example 7 Composition of the compound Epoxy resin (B) 100 100 Epoxy resin (D) 100 Phenol Novolac 38 39 Novolac type resin (A) 73 TPP 1 1 1 Cured product Physical properties Water absorption rate (%) 0.81 0.82 0.65 Izod impact test value (KJ / m ² ) 27.3 26.5 28.7

[0058]

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 Formula (1), n shows an average value and takes a value of 0-10.
P and R are each a hydrogen atom, a halogen atom, and a carbon number of 1 to
8 represents either an alkyl group or an aryl group,
Individual P and R may be the same or different from each other. ) Is a novolac type resin represented by
In the (gel permeation chromatography) analysis, the ratio of n = 0 in the formula (1) is 7 in area ratio.
A novolac resin that is 0% or less. (2) Formula (2) (In the formula (2), n, P and R have the same meanings as in the formula (1), and G represents a glycidyl group.) An epoxy resin represented by the formula (2) in GPC analysis. )
An epoxy resin in which the ratio of n = 0 in is 70% or less in area ratio. 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, which contains 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 any one of claims 3, 4, 5, 6 and 7.