JP3476584B2 - Epoxy resin, epoxy resin composition and cured product thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention has excellent heat resistance and water resistance,
Moreover, the present invention relates to an epoxy resin and an epoxy resin composition which give a cured product having excellent mechanical strength.

[0002]

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

[0003]

However, the general-purpose epoxy resin as described above has a drawback that the heat resistance of the cured product obtained by using the general-purpose epoxy resin decreases as the molecular weight increases. Further, when a polyfunctional epoxy resin such as an orthocresol novolac epoxy resin is added to a general-purpose epoxy resin, the heat resistance of the cured product is improved, but the water resistance and toughness are deteriorated.

[0004]

In view of these circumstances, the present inventors have earnestly studied for an epoxy resin which gives a cured product excellent in heat resistance, water resistance and toughness, and as a result, the following specific epoxy resin Excellent heat resistance in cured products,
The present invention has been completed by finding that it imparts water resistance and toughness.

That is, the present invention is Expression (1)

[0006]

[Chemical 2]

(In the formula, n represents an average value and represents a positive number.
P and Q represent any one of a halogen atom, an alkyl group having 1 to 8 carbon atoms and an aryl group, and each P and Q may be the same or different from each other. Each G represents a glycidyl group. Further, each X represents a hydrogen atom or a glycidyl group, and each X may be the same as or different from each other, but 0% to 95% of n Xs present are glycidyl groups. ) Epoxy resin represented by

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

Although n in the formula (1) represents a positive number, it is preferably in the range of 0.01 to 5. Among the epoxy resins represented by the formula (1), those in which n Xs are all hydrogen atoms are represented by, for example, the following formula (2)

[0010]

[Chemical 3]

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

It can be obtained by reacting the compound represented by and epihalohydrin with coexistence of an alkali metal hydroxide.

Further, by reacting the epoxy resin obtained above with the compound represented by the formula (2) in a specific ratio, a polymer having a larger value of n in the formula (1) is obtained. You can also get it.

Further, in the formula (1), the ratio of n Xs being glycidyl groups (hereinafter referred to as glycidylation rate) is 0.
% And 95% or less, the reaction of the epoxy resin obtained by the above-mentioned method with epihalohydrin is dimethyl sulfoxide, quaternary ammonium salt or 1,3.
It can be obtained by carrying out in the coexistence of dimethyl-2-imidazolidinone and an alkali metal hydroxide. The present inventors have found that the alcoholic hydroxyl group of the epoxy resin obtained by this method is more reactive than that of general alcohols, and for example, dimethyl sulfoxide, quaternary ammonium or 1,3-dimethyl-2-imidazolidinium. Surprisingly, the coexistence of non-alkali metal hydroxide selectively reacts with the newly added epihalohydrin-derived epoxy group only in the reaction between the alcoholic hydroxyl group and the epoxy group present in the reaction mixture. Can be done
Further, it was found that the alcoholic hydroxyl group of the epoxy resin represented by the formula (1) can be epoxidized to a desired ratio by adjusting the amount of the alkali metal hydroxide, and the present invention has been completed.

The details of the present invention will be described below. Formula (2)
As a general method for producing the compound represented by the following formula (3)

[0016]

[Chemical 4]

(In the formula, Y represents a hydroxyl group, halogen, or a methoxy group or an ethoxy group, and Q has the same meaning as in formula (1).)

The condensation reaction of the compound represented by and the phenol with an acid catalyst is exemplified, but not limited thereto.

Here, the phenols correspond to compounds having at least one phenolic hydroxyl group, and examples thereof include phenol, ethylphenol, n-propylphenol, isobutylphenol, t-butylphenol, octylphenol, nonylphenol, xylenol,
Various alkylphenol o-, m-, typified by methylbutylphenol, di-t-butylphenol, etc.
p-isomer, or various o-, m-, p-isomers of vinylphenol, allylphenol, propenylphenol, ethynylphenol, or cycloalkylphenol typified by cyclopentylphenol, cyclohexylphenol, cyclohexylcresol, cyclohexylcresol, etc. And other substituted phenols.

When the above condensation reaction is carried out, the amount of the phenols used is preferably 1.0 to 20 mol, particularly preferably 1.0 to 10 mol, relative to 1 mol of the compound represented by the formula (3).
It is in the molar range.

In the above condensation reaction, it is preferable to use an acid catalyst, and various kinds of acid catalysts can be used, but inorganic or organic acids such as hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, boron trifluoride and anhydrous chloride are used. Lewis acids such as aluminum and zinc chloride are preferable, and hydrochloric acid and p-toluenesulfonic acid are particularly preferable. The amount of these acid catalysts used is not particularly limited, but is 0.01 to 50 mol per 1 mol of the compound represented by the formula (3).

After the condensation reaction, the reaction product is dissolved in an organic solvent and neutralized or washed with water to remove the acid catalyst. Specific examples of the organic solvent that can be used in this case include toluene, xylene, and methyl isobutyl ketone, with toluene being preferred. The amount of the organic solvent used is preferably 50 to 300% by weight, especially 1
It is preferably from 0 to 250% by weight.

Next, the oil layer is concentrated under heating and reduced pressure, and unreacted phenols and organic solvent are removed to obtain a glassy solid. The obtained glassy solid is dissolved in an organic solvent such as toluene, xylene and methyl isobutyl ketone, and a poor solvent such as n-hexane and n-heptane is added,
The compound represented by the formula (2) can be obtained by recrystallization.

Among the epoxy resins represented by the formula (1), X
A known method can be adopted as a method for obtaining all of the hydrogen atoms (having a glycidylation rate of 0%). 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 (2) and an excess of epihalohydrin, or 20-
It can be obtained by reacting at a temperature of 120 ° C. for 1 to 20 hours. In the above reaction, an aqueous solution of the alkali metal hydroxide may be used, and in that case, an aqueous solution of the alkali metal hydroxide is continuously added to the reaction mixture and continuously under reduced pressure or under normal pressure. Alternatively, water and epihalohydrin may be distilled off, the liquid may be separated, water may be removed, and epihalohydrin may be 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 compound represented by the formula (2) and epihalohydrin, and the mixture is added at 50 to 150 ° C. The solid or aqueous solution of an alkali metal hydroxide is added to the halohydrin etherified product of the compound of formula (2) obtained by the reaction in step (1), and the mixture is reacted again at a temperature of 20 to 120 ° C. for 1 to 20 hours to dehydrohalogenate ( A method of ring closure) may be used.

Usually, the amount of epihalohydrin used in these reactions is usually 1 to 20 mol, preferably 1.5 to 10 mol per 1 equivalent of the hydroxyl group of the compound represented by the formula (2).
It is 10 mol. The amount of the alkali metal hydroxide used is 0.8 to 1 equivalent of the hydroxyl group of the compound represented by the formula (2).
It is 1.5 mol, preferably 0.9 to 1.1 mol. In order to allow the reaction to proceed smoothly, it is preferable to carry out the reaction by adding alcohols such as methanol and ethanol, as well as an aprotic polar solvent such as dimethyl sulfone and dimethyl sulfoxide.

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

After the reaction products of these epoxidation reactions are washed with water or without heating and under reduced pressure with heating, epihalohydrin and other added solvents are removed, so that the glycidylation rate in formula (1) is 0%. The epoxy resin of the invention can be obtained.

Further, by reacting the epoxy resin thus obtained with the compound represented by the formula (2) in the presence of a basic catalyst, a high molecular weight compound having a larger n value in the formula (1) is obtained. An epoxy resin can be obtained. In this polymerization reaction, the charging ratio of each component is such that the hydroxyl group equivalent of the compound represented by the formula (2) is 0 to 0.9 equivalent to 1 equivalent of the epoxy group of the epoxy resin obtained in the above reaction. Is preferred, and particularly preferably 0 to 0.85 equivalent.

The basic catalyst includes, for example, triphenorphosphine, sodium hydroxide, quaternary ammonium salt, imidazoles, etc., and the amount thereof is used with respect to 1 equivalent of the low molecular weight epoxy resin obtained by the above reaction. 0.001 to 1.0% by weight is preferable, and 0.005 is particularly preferable.
~ 0.5 wt% is preferred. When using a solvent,
Examples thereof include methyl isobutyl ketone and toluene.
The reaction temperature is preferably 60 to 200 ° C., particularly 70 to 19
0 ° C is preferred. The reaction time is preferably 0.5 to 20 hours, particularly preferably 1 to 15 hours. In this way, an epoxy resin having a glycidyl ratio of 0% in the formula (1) can be obtained.

In the formula (1), the reaction between the alcoholic hydroxyl group of the epoxy resin having a glycidyl ratio of 0% and epihalohydrin is performed by using dimethyl sulfoxide or a quaternary ammonium salt or 1,3-dimethyl-2-imidazolidinone and an alkali metal. It can be carried out by adjusting the amount of the alkali metal hydroxide in the presence of hydroxide. At that time, alcohols such as methanol and ethanol, aromatic hydrocarbons such as toluene and xylene, ketones such as methyl isobutyl ketone and methyl ethyl ketone, and cyclic and ether compounds such as tetrahydrofuran may be used together as the solvent.

The amount of dimethyl sulfoxide or 1,3-dimethyl-2-imidazolidinone used is preferably 5 to 300% by weight based on the epoxy resin used as a raw material. When it exceeds 300% by weight with respect to the raw material epoxy resin, the effect of increasing the amount is almost lost, but the volume efficiency is deteriorated, which is not preferable.

Specific examples of the quaternary ammonium salt include tetramethylammonium chloride, tetramethylammonium bromide, trimethylammonium chloride, and the like. The amount used is the alcoholic hydroxyl group of the epoxy resin used as the raw material to be epoxidized. 0.3 to 50 g is preferable for 1 equivalent. If the amount of the hydroxyl group to be epoxidized is less than 0.3 g per 1 equivalent, the reaction between the alcoholic hydroxyl group of the epoxy resin used as a raw material and the epihalohydrin is delayed, which requires a long reaction time, which is not preferable. When the amount exceeds 50 g per equivalent of the alcoholic hydroxyl group to be epoxidized, the effect of increasing the amount is almost lost but the cost becomes high, which is not preferable.

The amount of epihalohydrin used may be equal to or more than 1 equivalent of the alcoholic hydroxyl group to be epoxidized in the epoxy resin used as a raw material. However, if the amount exceeds 20 times the equivalent of the hydroxyl group to be epoxidized, the effect of increasing the amount will almost disappear, and the volume efficiency will deteriorate, which is not preferable.

As the alkali metal hydroxide, sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide and the like can be used, but sodium hydroxide is preferred. The amount of the alkali metal hydroxide used may be 1 to 2 times equivalent to 1 equivalent of the alcoholic hydroxyl group to be epoxidized in the epoxy resin used as a raw material. The alkali metal hydroxide may be solid or aqueous solution. Further, when an aqueous solution is used, the reaction can be carried out during the reaction while distilling the water in the reaction mixture out of the reaction mixture under normal pressure or reduced pressure.

The reaction temperature is 20 to 100 ° C. and the reaction time is 1
~ 20 hours is preferred. If the reaction temperature is lower than 20 ° C, the reaction becomes slow and a long-time reaction is required. When the reaction temperature exceeds 100 ° C., many side reactions occur, which is not preferable.

The epoxy resin of the present invention can be cured alone or in combination with other epoxy resins by adding a curing agent, and if necessary, a curing accelerator, as in the case of a usual epoxy resin. The curing agent that can be used in the present invention is an amine compound, an acid anhydride compound, an amide compound, a phenol compound or the like. Specific examples thereof include diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, dicyandiamide,
Polyamide resin synthesized from dimer of linolenic acid and ethylenediamine, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, Hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, phenol novolac,
And modified products thereof, imidazole, BF ₃ -amine complex, guanidine derivative and the like. These curing agents may be used alone or in combination of two or more.

The amount of these curing agents used is preferably 0.7 to 1.2 equivalents based on the epoxy group. If the amount is less than 0.7 equivalents or more than 1.2 equivalents with respect to the epoxy groups, the 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. Examples of usable curing accelerators include imidazoles such as 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2- (dimethylaminomethyl) phenol, and the like.
1,8-diaza-bicyclo (5,4,0) undecene-
And tertiary amines such as 7; phosphines such as triphenylphosphine; and metal compounds such as tin octylate. When the curing accelerator is used, the amount used is 0.1 to 5.0 parts by weight based on 100 parts by weight of the epoxy resin, if necessary. Further, if necessary, various compounding agents such as a filler such as silica, alumina, talc, a silane coupling agent, a release agent, 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 above components in a predetermined ratio. The cured product of the epoxy resin composition of the present invention can be easily obtained by the same method as a conventionally known method. For example, the epoxy resin of the present invention, a curing agent, and if necessary, a curing accelerator and other compounding agents are mixed as necessary with an extruder, a kneader, a roll, etc. until they are homogeneous, and then the epoxy resin is mixed. The cured product of the present invention can be obtained by obtaining a resin composition, molding the epoxy resin composition after melting using a casting or transfer molding machine, and further heating at 80 to 200 ° C.

The prepreg obtained by dissolving the resin composition of the present invention in a solvent, impregnating it into a substrate such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, alumina fiber, paper, etc. and drying by heating is heated. A cured product can be obtained by press molding.

Specific examples of the diluting solvent used at this time are methyl ethyl ketone, acetone, methyl isobutyl ketone, etc., and the amount thereof is usually 10 to 70% by weight in the mixture of the epoxy resin composition of the present invention and the diluent. It is preferably 15 to 65% by weight.

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

[0044]

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. The conditions for measuring the glass transition temperature, the water absorption rate, and the bending strength are as follows. Glass transition temperature thermomechanical measuring device (TMA): Vacuum Riko TM-7000 Temperature rising rate: 2 ° C./min Water absorption test piece (cured product): Diameter 50 mm Thickness 3 mm Disc 100 ° C. After boiling in water Weight increase rate (%) Bending strength Conforms to JIS K-6911

Example 1 732 parts of 2,6-xylenol in a flask equipped with a thermometer, a cooling tube, a fractionating tube and a stirrer, the following formula (4)

[0046]

[Chemical 5]

150 parts of a compound represented by
After stirring and melting at 120C, the mixture was cooled to 120C, 1 part of p-toluenesulfonic acid (monohydrate) was charged, and the mixture was reacted at 120C for 5 hours. After the reaction was completed, 5 parts of a 20% aqueous sodium hydrogen phosphate solution was added and stirred, and then unreacted substances were removed under heating and reduced pressure to obtain a glassy solid. Then, after recrystallizing in toluene / n-heptane, the crystals are washed with cold toluene and dried under reduced pressure to obtain the following formula (5).

[0048]

[Chemical 6]

330 parts of a compound of the formula Then, 211 parts of the compound represented by the formula (5), 370 parts of epichlorohydrin, and 92.5 parts of dimethyl sulfoxide were charged and dissolved in a flask equipped with a thermometer, a cooler, and a stirrer while purging with nitrogen gas. After further heating to 45 ° C., 40 parts of flaky sodium hydroxide was added portionwise over 100 minutes, and then at 45 ° C. for 2 hours at 70 ° C.
The reaction was carried out at 0 ° C for 1 hour. After completion of the reaction, excess epichlorohydrin and dimethylsulfoxide were distilled off under reduced pressure with heating at 130 ° C. and 5 mHg using a rotary evaporator, and 540 parts of methyl isobutyl ketone was added and dissolved in the residue.

Further, this methyl isobutyl ketone solution was heated to 70 ° C., 10 parts of a 30% by weight sodium hydroxide aqueous solution was added thereto, and the mixture was reacted for 1 hour.
H was neutral. Further, the water layer is separated and removed, and methyl isobutyl ketone is distilled off from the oil layer under reduced pressure by heating using a rotary evaporator to obtain the following formula (6).

[0051]

[Chemical 7]

(Where n is 0.05 (average value), and G
Represents a glycidyl group. Further, X is all hydrogen atoms. ) Semi-solid epoxy resin (A) of the present invention represented by
251 parts were obtained. The epoxy equivalent of the obtained epoxy resin was 279 g / eq.

Example 2 140 parts of the epoxy resin (A) obtained in Example 1, 30 parts of the compound represented by the formula (5), and 85 parts of methyl isobutyl ketone were charged in a flask and dissolved by stirring. Add 0.1 parts of phenylphosphine and stir 120
Distill off methyl isobutyl ketone under reduced pressure at ℃
The present invention having an epoxy equivalent of 480 g / eq and a softening point of 90.5 ° C., in which all X in the formula (6) are hydrogen atoms, the value of n is 0.89 (average value), and the reaction is carried out at 0 ° C. for 2 hours. 167 parts of epoxy resin (B) was obtained.

Example 3 161 parts of the epoxy resin (B) obtained in Example 2 was dissolved in 278 parts of epichlorohydrin with stirring, and then 4 with stirring.
At 0 ° C. 1 part tetramethylammonium chloride was added. After that, 7.2 parts of flaky sodium hydroxide was added, and the reaction was further performed for 3 hours. After the completion of the reaction, 130 parts of water was added and washed with water. After separation of oil and water, unreacted epichlorohydrin was recovered by distillation under reduced pressure to obtain 163 parts of the epoxy resin (C) of the present invention. The obtained epoxy resin (C) had a value of n of 0.89 in the formula (6), an epoxy equivalent of 369 g / eq, and a softening point of 78.9 ° C.
The glycidylation rate of the obtained epoxy resin was 80% when calculated from the epoxy equivalent.

Examples 4 to 6 Epoxy resins (A), (B), (C) and phenol novolac (hydroxyl group equivalent 106 g / eq, softening point 83 ° C.) as a curing agent were used. Blend with the composition shown in the column and knead with a roll at 70 ° C for 15 minutes to obtain 150
Transfer molding at 180 ℃ for 180 seconds, then 160
A glass transition temperature, a water absorption rate, and a bending strength were measured by curing a test piece at 2 ° C. for 2 hours and then at 180 ° C. for 8 hours to prepare a test piece. The results are shown in Table 1. In the table, the numerical values in the column of composition of formulation represent parts.

[0056]

Table 1 Example 4 Example 5 Example 5 Composition of the formulation Epoxy resin (A) 100 Epoxy resin (B) 100 Epoxy resin (C) 100 (Epoxy equivalent (g / eq)) 278 480 369 Phenol Novolac 38.0 22.1 28.7 Physical properties of cured product Glass transition temperature (℃) 159 154 162 Water absorption rate (%) 0.85 0.79 0.76 Bending strength (Kg / mm ² ) 13.4 14.5 13.0

As is clear from Table 1, the cured product obtained by using the epoxy resin of the present invention has a high glass transition temperature, a low water absorption rate, a high bending strength, and high heat resistance, water resistance and mechanical strength. It has the characteristics of being excellent.

[0058]

INDUSTRIAL APPLICABILITY The epoxy resin of the present invention can give a cured product excellent in heat resistance, water resistance and mechanical strength, and can be used in a wide range of molding materials, casting materials, laminating materials, paints, adhesives, resists and the like. It is extremely useful for applications.

Continuation of front page (56) Reference JP-A-8-208802 (JP, A) JP-A-7-292066 (JP, A) JP-A-6-271654 (JP, A) JP-A-3-285909 (JP , A) JP-A-7-196568 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08G 59/24 C08G 59/06

Claims (3)

(57) [Claims] 1. A formula (1): (In the formula, n represents an average value and represents a positive number. Each P represents a halogen atom, an alkyl group having 1 to 8 carbon atoms or an aryl group, and each P is the same or different. Q represents a hydrogen atom, each G represents a glycidyl group, each X represents a hydrogen atom or a glycidyl group, and each X may be the same or different from each other. However, an epoxy resin represented by 0 to 95% of n which is n is a glycidyl group.). 2. An epoxy resin composition containing the epoxy resin according to claim 1, a curing agent, and optionally a curing accelerator. 3. A cured product obtained by curing the epoxy resin composition according to claim 2.