JPH093162A - Epoxy resin mixture, epoxy resin composition, and its cured product - Google Patents

Abstract

PURPOSE: To obtain an epoxy resin composition whose melt viscosity is low and whose cured product is excellent in heat resistance by subjecting phenols to a condensation reaction with glyoxal in the presence of an acid catalyst and purifying the product followed by glycidyl etherification. CONSTITUTION: Phenols are subjected to a condensation reaction with glyoxal in the presence of an acid catalyst to prepare a mixture comprising a compound having formula I (R represents H, a C1 to C9 alkyl, aryl, or a halogen). Then the mixture is purified to produce a mixture wherein a compound of formula II is present in an amount of 80mol% or more and preferably 85mol% or more. This mixture is subjected to glycidyl etherification to produce an epoxy resin mixture comprising a compound represented by formula III (G represents a glycidyl group), in which epoxy resin mixture, a compound represented by formula IV is present in a total amount of 80mol or more with respect to the total amount of the compound of formula III assumed to be 100mol. Since the obtained epoxy resin mixture can be filled with a large amount of a filler to give a cured product excellent in heat resistance, it is useful, for example, for casting materials, paints and adhesives.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin mixture and an epoxy resin composition which have a low melt viscosity, can be filled with a high amount of filler, and give a cured product having excellent heat resistance.

[0002]

2. Description of the Related Art Epoxy resins can be cured with various curing agents to give cured products having generally 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, 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 bromine-containing epoxy resin obtained by reacting the resin A is industrially used as a general-purpose epoxy resin. In addition, especially as a semiconductor encapsulation application, a polyfunctional epoxy resin obtained by reacting orthocresol novolac with epichlorohydrin is mainly used.

[0003]

However, as the molecular weight of the above-mentioned orthocresol novolac type epoxy resin increases, the heat resistance of the cured product obtained by using it increases, but the melt viscosity increases. There is a drawback that. Further, an orthocresol type epoxy resin having a small molecular weight, a crystalline tetramethylbiphenol type epoxy resin, or the like has a drawback that although the melt viscosity is low, the heat resistance of the cured product is lowered.
In recent years, in order to improve the performance of a semiconductor encapsulant, it has been required to develop an epoxy resin having a low viscosity so that a filler can be highly filled and a cured product thereof having high heat resistance.

[0004]

In view of these circumstances, the inventors of the present invention have earnestly studied for an epoxy resin which gives a cured product having a low viscosity and excellent heat resistance, and as a result, a compound having the following specific structure was identified as glycidyl. The present invention has been completed by finding that the epoxy resin mixture obtained by etherification has a very low melt viscosity and imparts excellent heat resistance to the cured product.

That is, the present invention relates to (1) Formula (1)

[0006]

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(Wherein R represents a hydrogen atom, an alkyl group having 1 to 9 carbon atoms, an aryl group, or a halogen atom, which may be the same or different from each other. G represents a glycidyl group). A total amount of the compounds represented by formula (1) in the mixture is 100.
And the total number of moles of the compound represented by the following formula (2) is 80 or more, an epoxy resin mixture,

[0008]

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(In the formula, R and G have the same meanings as in formula (1).) (2) The epoxy resin mixture, the curing agent, described in (1) above.
An epoxy resin composition containing a curing accelerator if necessary,
(3) A cured product obtained by curing the epoxy resin composition according to (2) above is provided.

Hereinafter, the present invention will be described in detail. Equation (1)
Known methods can be used to obtain the represented compounds. For example, phenols are condensed with glyoxal in the presence of an acid catalyst. Specific examples of phenols that can be used include phenol, cresol, ethylphenol, n-propylphenol, isobutylphenol,
Various o-, m of alkyl monosubstituted phenols such as t-butylphenol, octylphenol, nonylphenol
-, P-isomers, various o-, m-, p-isomers of alkyl disubstituted phenols such as xylenol, methylethylphenol, methyl-n-propylphenol, methylisobutylphenol and methyl-t-butylphenol, and these The halogen-substituted product of These may be used alone or in combination of two or more. The amount of phenols used is usually 4 to 50 mol, preferably 5 to 40 mol, per 1 mol of glyoxal. An aqueous solution of glyoxal is usually used.

Specific examples of the acid catalyst which can be used in the condensation are usually inorganic or organic acids such as p-toluenesulfonic acid, hydrochloric acid, sulfuric acid and oxalic acid or Lewis acids such as boron trifluoride, anhydrous aluminum chloride and zinc chloride. Among them, p-toluenesulfonic acid, hydrochloric acid and sulfuric acid are particularly preferable. The amount of these acid catalysts used is not particularly limited, but is usually 0.001 to 1 mol with respect to 1 mol of glyoxal.
0.1 mol.

The above reaction can be carried out without solvent or in the presence of an organic solvent. Specific examples of the organic solvent that can be used include toluene, xylene, and methyl isobutyl ketone. The amount of the organic solvent used is preferably 50 to 300% by weight, and particularly preferably 100 to 250% by weight, based on the total weight of the raw materials charged. The reaction temperature is usually 5
The reaction time is usually 1 to 10 hours.

After completion of the reaction, neutralization treatment or water washing treatment is carried out, and then the unreacted phenols and solvent are distilled off under heating and reduced pressure to concentrate the product. In this way, a mixture of the compounds represented by the following formula (3) can be obtained.

[0014]

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(Wherein R has the same meaning as in formula (1).) Then, purification is repeated by a known method from a mixture of the compounds represented by formula (3) and represented by formula (4). A mixture having a molar fraction of the compound of 80% or more, preferably 85% or more is obtained.

[0016]

[Chemical 6]

(Wherein R has the same meaning as in formula (1).) Here, the purification method is not particularly limited, and for example, the obtained glassy solid is treated with toluene, xylene, methyl isobutyl ketone, or the like. Examples include a method of dissolving crystals in an organic solvent and adding a poor solvent such as n-hexane or n-heptane several times to precipitate crystals. Besides the above method, the method described in JP-A-7-76538 may be applied. A mixture of the compounds represented by formula (3) thus obtained, wherein the compound represented by formula (4) has a molar fraction of 80% or more, preferably 85.
A mixture having a content of at least% is hereinafter referred to as a mixture (A) unless otherwise specified.

As a method for obtaining the epoxy resin mixture of the present invention from the mixture (A), a known method can be adopted. For example, it can be obtained by adding an alkali metal hydroxide to a dissolved mixture of the mixture (A) and excess epihalohydrin, or by reacting at a temperature of 20 to 120 ° C. while adding. In the above reaction, an aqueous solution of the alkali metal hydroxide may be used, and in that case, the aqueous solution of the alkali metal hydroxide is continuously added to the reaction mixture and continuously under reduced pressure or 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.

A mixture obtained by adding a quaternary ammonium salt such as tetramethylammonium chloride, tetramethylammonium bromide or trimethylbenzylammonium chloride as a catalyst to a dissolved mixture of the mixture (A) and epihalohydrin and reacting at 50 to 150 ° C. A method of adding a solid or aqueous solution of an alkali metal hydroxide to the halohydrin etherified product of (A) and reacting at a temperature of 20 to 120 ° C. for dehydrohalogenation (ring closure) may be used.

The amount of epihalohydrin used in these reactions is usually 1 to 20 mol, preferably 1.5 to 10 mol, based on 1 equivalent of the hydroxyl group of the mixture (A). The amount of the alkali metal hydroxide used is 0.8 to 1.5 mol, preferably 0.9 to 1.1 mol, relative to 1 equivalent of the hydroxyl group of the mixture (A). 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 40% by weight, more preferably 4 to 30% 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 washing these reaction products of the epoxidation reaction with or without washing with water, the epihalohydrin and the solvent are removed under heating and reduced pressure, and further post-treatment is carried out if necessary.
The post-treatment dissolves the obtained epoxy resin in a hydrophobic solvent. Specific examples of the hydrophobic solvent that can be used include methyl isobutyl ketone, benzene, toluene, xylene and the like, and methyl isobutyl ketone and toluene are preferable. These can be used alone or in combination.

Then, 0.025 to 0.3 mol of alkali metal hydroxide is added to 1 mol of the hydroxyl group of the mixture (A) used as a raw material, and preferably 3 at 40 to 90 ° C.
Stir for 0 to 3 hours to carry out the dehalogenation reaction. On this occasion,
As the alkali metal hydroxide, it is preferable to use an aqueous solution of 5 to 50% by weight.

After completion of the reaction, the obtained resin solution is washed with water several times, and then the hydrophobic solvent is distilled off under reduced pressure to obtain the desired epoxy resin mixture.

The epoxy resin mixture 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 and the like as in the case of ordinary epoxy resins. . When the epoxy resin mixture of the present invention is used in combination with another epoxy resin, the proportion of the epoxy resin mixture of the present invention in the total epoxy resin is preferably 30% by weight or more, and particularly preferably 40% by weight or more. In this case, an example of the epoxy resin that can be used is usually a compound having two or more epoxy groups in one molecule, and there is no particular limitation as long as it is a compound generally used for electronic devices. For example, novolac type epoxy resin such as phenol novolac type epoxy resin, cresol novolac type epoxy resin, naphthol novolac type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol S type epoxy resin, Epoxy resins obtained from aromatic dihydric phenols such as bisphenol I type epoxy resins and biphenyl type epoxy resins, glycidyl ester type epoxy resins obtained by reacting polybasic acids such as phthalic acid and dimer acid with epihalohydrin, and diamino Diphenylmethane,
Examples thereof include a glycidyl amine type epoxy resin obtained by reacting a polyamine such as isocyanuric acid with epihalohydrin. These epoxy resins may be used alone or in combination of two or more.

The curing agent used in the present invention is an amine compound,
Examples thereof include 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, trianhydride. Mellitic acid, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride,
Examples include methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, phenol novolak, and modified products thereof, imidazole, BF ₃ -amine complex, and guanidine derivative. Further, the mixture (A) used when preparing the epoxy resin mixture of the present invention can also be used as a curing agent. 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 group, curing may be incomplete and good cured physical properties may not be obtained.

A curing accelerator may be added to the epoxy resin composition of the present invention. Specific 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-. Examples thereof include 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. Further, various compounding agents such as inorganic or organic fillers such as silica, alumina and talc, silane coupling agents, release agents, pigments and the like can be added to the epoxy resin composition of the present invention as required.

The epoxy resin composition of the present invention containing the epoxy resin mixture of the present invention, a curing agent and, if necessary, a curing accelerator can be easily obtained by a method similar to the conventionally known method. it can. For example, the epoxy resin mixture of the present invention, a curing agent, and if necessary, a curing accelerator and other compounding ingredients are sufficiently mixed by using an extruder, a kneader, a roll, etc., if necessary, until uniform. An epoxy resin composition is obtained, and the epoxy resin composition is melted and then molded using a casting or transfer molding machine.
The cured product can be obtained by heating to 0 to 200 ° C.

Further, a prepreg obtained by dissolving the epoxy 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 and heating and drying it It is also possible to obtain a cured product by hot press molding.

Specific examples of the solvent that can be used in this case include methyl ethyl ketone, acetone and methyl isobutyl ketone. The solvent is usually 10 to 70% by weight, preferably 15 to 70% by weight in the mixture of the epoxy resin composition and the solvent.
An amount occupying 65% by weight is used.

[0032]

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 conditions for measuring the glass transition temperature and the water absorption are as follows. Melt viscosity I. C. I Cone and plate viscometer: Research Equipment Co., Ltd. glass transition temperature thermomechanical measuring device (TMA): TM-70 manufactured by Vacuum Riko Co., Ltd.
00 Temperature rising rate: 2 ° C / min

Example 1 A flask equipped with a thermometer, a cooler and a stirrer was purged with nitrogen gas while the following formula (5)

[0034]

[Chemical 7]

A mixture of compounds represented by the formula (6)

[0036]

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149 parts of a mixture having a molar fraction of the compound represented by the formula of 98%, 555 parts of epichlorohydrin and 111 parts of methanol were charged and dissolved. The mixture was further heated to 70 ° C., 60 parts of flaky sodium hydroxide was added portionwise over 100 minutes, and then the mixture was further reacted at 70 ° C. for 75 minutes. After completion of the reaction, use a rotary evaporator to
Excessive epichlorohydrin and methanol were distilled off under reduced pressure with heating at 5 ° C and 5 mHg, and 470 parts of methyl isobutyl ketone was added to the residue and dissolved.

Further, this methyl isobutyl ketone solution was heated to 70 ° C., 23 parts of methanol and 10 parts of a 30% by weight sodium hydroxide aqueous solution were added, and the mixture was reacted for 1 hour. It was sex. Further, the aqueous 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 (7).

[0039]

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A mixture of compounds represented by the formula (wherein G represents a glycidyl group), which is represented by the formula (8):

[0041]

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219 parts of the epoxy resin mixture (A) of the present invention was obtained in which the compound represented by the formula (wherein G represents a glycidyl group) had a mole fraction of 98%. The epoxy equivalent of the obtained epoxy resin mixture was 164 g / eq, the melt viscosity at 150 ° C. was 0.4 poise, and the softening point was 81.4 ° C.

Example 2 Epoxy resin mixture (A), phenol novolac as a curing agent (hydroxyl equivalent 106 g / eq, softening point 80 ° C.)
Was blended with the composition shown in the column of the composition of the blend in Table 1 and kneaded with a roll at 70 ° C. for 15 minutes to obtain 150 ° C., 180
The glass transition temperature was measured by transfer molding in seconds and then curing at 160 ° 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 addition, the numerical value in the column of the composition of the compound in the table represents part.

[0044]

[Table 1] Table 1 Composition of compound Epoxy resin mixture (A) 100 Phenol novolac 64.6 Physical properties of cured product Glass transition temperature (° C) 192

[0045]

Although the epoxy resin mixture or composition of the present invention has an appropriate softening point and an extremely low melt viscosity, a cured product obtained by using the epoxy resin mixture or composition has very high heat resistance. It has characteristics. That is, the epoxy resin mixture of the present invention can be filled with a high amount of filler and can give a cured product having excellent heat resistance, and is suitable for a wide range of applications such as molding materials, casting materials, laminating materials, paints, adhesives and resists. It is extremely useful, and can also be used as an ultraviolet curable resin by reacting with acrylic acid or methacrylic acid.

Claims (3)

[Claims] (1) Formula (1) (Wherein R represents a hydrogen atom, an alkyl group having 1 to 9 carbon atoms, an aryl group, or a halogen atom and may be the same or different from each other. G represents a glycidyl group). The total number of moles of the compound represented by the following formula (2) is 80 or more, when the total number of moles of the compound represented by the formula (1) in the mixture is 100. An epoxy resin mixture characterized by: Embedded image (In the formula, R and G have the same meanings as in formula (1).) 2. An epoxy resin composition containing the epoxy resin mixture 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.