JPH10279669A - Epoxy resin hardener - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a hardener which can give a cured product having excellent heat resistance, reduced bending modulus and water absorptivity, low stress and excellent humidity resistance by using a phenol/alkylbenzene/aldehyde resin prepared by polycondensing an alkylbenzene/aldehyde resin with a phenol in a specified weight ratio in the presence of an acid catalyst and reacting the polycondensate with an aldehyde as the principal component. SOLUTION: This hardener mainly consists of a phenol/alkylbenzene/aldehyde resin prepared by polycondensing an alkylbenzene/aldehyde resin (A) prepared by reacting an alkylbenzene represented by formula I (wherein R1 is a 1-8C alkyl; and m is 1-4) with an aldehyde (Y1) represented by formula II (wherein R2 is H or a 1-7C monovalent hydrocarbon group; and Y1 and Y2 may be the same or different from each other) in the presence of an acid catalyst with a phenol (Z) represented by one of formulas III and IV (wherein R3 is H, a 1-8C alkyl, an alkenyl or a halogen; and n is 1-3) in a weight ratio: 1<=Z/A<=20 in the presence of an acid catalyst and reacting the polycondensate with an aldehyde (Y2).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a phenol-alkylbenzene-containing compound which exhibits good curability in a curing reaction with an epoxy resin, and has excellent heat resistance, low stress and excellent moisture resistance. The present invention relates to an epoxy resin curing agent containing an aldehyde resin as a main component.

[0002]

2. Description of the Related Art Conventionally, acid anhydrides, amine compounds, imidazole compounds,
Novolak-type phenolic resins have been used, but in recent years, as a curing agent for epoxy resins for semiconductor encapsulants, because of the excellent moldability, heat resistance, moisture resistance, and electrical properties of cured epoxy resins, Novolak phenolic resins are widely used.

[0003] In recent years, however, chips have become larger in size with higher integration of integrated circuits, the mounting method has changed from the insertion method to surface mounting, and packages have become smaller and thinner. That is, since a large chip is exposed to a higher temperature than before in a state in which it is sealed in a thin package, a problem of a package crack occurs, and further reduction in stress and improvement in moisture resistance of the sealing material have been required.

In order to lower the stress and improve the moisture resistance of the sealing material, use of a xylene-modified phenol resin as a curing agent (Japanese Patent Application Laid-Open No. 59-105017) and use of a fluorine-containing novolak (Japanese Patent Application Laid-Open No. 64-74215). No.) was considered.
Also disclosed is a method for producing a polyhydroxy compound for an epoxy resin curing agent by condensing a phenol with a dimethylol derivative of a 4-alkylphenol or a 4-arylphenol (JP-A-62-119220).
No.). However, these materials have reduced strength even if the stress is reduced, and none of them has been sufficiently satisfactory as a curing agent for an epoxy resin sealing material.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an epoxy resin curing agent for a semiconductor encapsulant, exhibiting good curability in a curing reaction with an epoxy resin, and having excellent heat resistance and low stress. An object of the present invention is to provide an epoxy resin curing agent containing a phenol / alkylbenzene / aldehyde resin as a main component, which provides a semiconductor encapsulant having excellent moisture resistance.

[0006]

According to the present invention, there is provided a compound represented by the general formula (1):
An alkylbenzene-aldehyde resin (A) obtained by reacting an alkylbenzene (X) represented by the formula (X) with an aldehyde (Y1) represented by the formula (2) in the presence of an acid catalyst, and a compound represented by the formula (3) or (3) ) And (4) are polycondensed in the presence of an acid catalyst at a weight ratio of 1 ≦ (Z) / (A) ≦ 20, and then further represented by the general formula (2) An epoxy resin curing agent containing a phenol / alkylbenzene / aldehyde resin as a main component obtained by reacting an aldehyde (Y2).

Embedded image (In the formula, R ₁ represents an alkyl group having 1 to 8 carbon atoms, which may be the same or different, and m is an integer of 1 to 4.) R ₂ —CHO (2) ( In the formula, R ₂ represents hydrogen or a monovalent hydrocarbon group having 1 to 7 carbon atoms. Y 1 and Y 2 may be the same or different from each other.)

Embedded image

Embedded image (In the formula, R ₃ represents an atom or a group selected from hydrogen, an alkyl group having 1 to 8 carbon atoms, an alkenyl group, and a halogen, which may be the same or different. Is an integer of 1 to 3.)

The alkylbenzenes (X) used in the present invention include toluene, xylene, mesitylene, cumene and the like, and m-xylene having a high reactivity with aldehydes (Y1, Y2) is particularly preferred. Aldehydes (Y1, Y2) are hydrocarbons having one aldehyde group and have 0 to 7 carbon atoms other than aldehyde group, and include formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, isovaleraldehyde, benzaldehyde and the like. Formaldehyde, which increases the crosslink density when cured with an epoxy resin, is particularly preferred. When the number of carbon atoms other than the aldehyde group is 8 or more, steric hindrance is large, and the curing reaction between the epoxy group and the hydroxyl group is inhibited, and the curability of the resin composition is lowered or the glass transition temperature of the cured product is lowered. Examples of the phenols (Z) include dihydric phenols such as resorcin, catechol, hydroquinone, methyl resorcin, chlororesorcin, phenol, cresol, t-butylphenol,
Monohydric phenols such as t-octylphenol and allylphenol are mentioned, but in the present invention, dihydric phenols are necessarily included. Of these, resorcinol, which gives a resin having a good balance between the hydroxyl equivalent, the softening point, and the solution viscosity, or a combination of dihydric phenols and phenol is preferable. The above-mentioned alkylbenzenes (X), aldehydes (Y1, Y2) and phenols (Z) are merely examples, and are not particularly limited. These may be used alone or as a mixture during the reaction.

The alkylbenzene-aldehyde resin in the present invention comprises an alkylbenzene (X) and an aldehyde (Y
1) can be easily obtained by reacting in the presence of an acid catalyst such as sulfuric acid. Further, m-xylene / formaldehyde resin and the like are commercially available from Mitsubishi Gas Chemical Co., Ltd. under the trade name "Nicanol" and can be easily obtained.

The phenol / alkylbenzene of the present invention
The aldehyde resin is obtained by polycondensing an alkylbenzene-aldehyde resin (A) obtained by reacting an alkylbenzene (X) with an aldehyde (Y1) in the presence of an acid catalyst and a phenol (Z) in the presence of an acid catalyst. And further reacted with an aldehyde (Y2). At the time of polycondensation of (A) and (Z), an organic solvent may be used as necessary. Examples of the organic solvent include ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, and alcohols such as methanol, ethanol, propanol and butanol, but are not particularly limited. They may be used alone or as a mixture.

As an example, m-xylene. Obtained by reacting m-xylene with formaldehyde in the presence of an acid catalyst.
A typical structure of a resorcin-m-xylene-formaldehyde resin obtained by polycondensing formaldehyde resin and resorcinol in the presence of an acid catalyst and then reacting with formaldehyde is shown in the general formula (5). It is not limited to the illustrated structure.

Embedded image (Where k is an integer of 0 to 10)

In the present invention, the weight ratio between (A) and (Z) is 1 ≦
If (Z) / (A) ≦ 20, desired characteristics can be obtained, and particularly preferably 1.2 ≦ (Z) / (A) ≦ 7.0. (Z)
When / (A) <1, the ratio of phenols in the phenol / alkylbenzene / aldehyde resin is reduced, and the curability and moldability of the epoxy resin composition are significantly reduced.
In the case of (Z) / (A)> 20, the ratio of the alkylbenzene-aldehyde resin in the phenol-alkylbenzene-aldehyde resin becomes small, and the cured product has a low elastic modulus in the rubber region, low water absorption, metals such as a lead frame, and the like. The effect of the alkylbenzene / aldehyde resin, such as high adhesiveness to the silicon chip, cannot be fully exhibited.

The hydroxyl equivalent of the phenol / alkylbenzene / aldehyde resin is preferably from 70 to 150 g / eq, particularly preferably from 90 to 130 g / eq. If the hydroxyl group equivalent is less than 70 g / eq, the softening point and the solution viscosity are low, and there is a concern that the room temperature storage property may be deteriorated due to moisture absorption and the workability may be problematic. When it exceeds 150 g / eq, the distance between the crosslinking points between the epoxy group and the phenolic hydroxyl group becomes large, and there is a possibility that the curability may decrease or the glass transition temperature of the cured product may decrease.

The softening point of the phenol / alkylbenzene / aldehyde resin is preferably from 60 to 120 ° C.
~ 95 ° C is preferred. If the softening point is lower than 60 ° C., the composition is in a liquid or semi-solid state at room temperature, and there is a possibility that the workability may deteriorate, the curability may decrease, or the glass transition temperature of the cured product may decrease. If it exceeds 120 ° C., it does not melt sufficiently when mixed with the epoxy resin, and uniform dispersion is not easy, so that the curability and moldability are reduced, and a nonuniform molded article is liable to be formed.

[0014] The solution viscosity of a phenol-alkylbenzene aldehyde resin is preferably 20~90μm ² / s, in particular 30 to 60 m ² / s are preferred. Solution viscosity 20μ
If it is less than m ² / s, there are many low molecular weight components which do not participate in the curing reaction in the resin, and there is a possibility that the curability may decrease or the glass transition temperature of the cured product may decrease. If it exceeds 90 μm ² / s, the melt viscosity is high and the fluidity is reduced, and poor moldability such as poor filling occurs.

The weight average molecular weight of the phenol / alkylbenzene / aldehyde resin is preferably from 400 to 3000, particularly preferably from 600 to 1500. If the weight average molecular weight is less than 400, it is liquid or semi-solid at room temperature,
There is a possibility that the workability is reduced, the curability is lowered, or the glass transition temperature of the cured product is lowered. If it exceeds 3,000, the melt viscosity is high and the fluidity is reduced, and poor moldability such as poor filling occurs.

These characteristics are based on the mixing ratio of alkylbenzenes and aldehydes, the reaction temperature, the reaction time, the mixing ratio of alkylbenzene-aldehyde resins and phenols,
It can be prepared by appropriately selecting the reaction temperature, the reaction time, the mixing ratio of the aldehydes, the reaction temperature, the reaction time, and the like.

In the present invention, the phenol / alkylbenzene / aldehyde resin may be used alone, or may be used in combination with one or more other epoxy resin curing agents.
Other epoxy resin curing agents include phenol / formaldehyde resin, cresol / formaldehyde resin,
Phenol / dicyclopentadiene resin, phenol /
Examples thereof include an alkylbenzene resin and the like, but are not particularly limited, and the addition ratio can be appropriately set according to desired requirements.

In the present invention, the characteristic values of the phenol / alkylbenzene / aldehyde resin are measured according to the following method.

The hydroxyl equivalent was determined by acetylating a sample with pyridine and an excess amount of acetic anhydride, and titrating acetic acid generated from acetic anhydride consumed by the sample with an aqueous sodium hydroxide solution.

The softening point was determined by the ring and ball method described in JIS K 7234.

Solution viscosity at 25 ° C., sample / ethanol =
It was determined by the method described in JIS Z8803 using a 5/5 solution.

The weight-average molecular weight was measured using a GPC column manufactured by Tosoh (G1000HXL: 1, G2000HXL: 2).
Bottle, G3000HXL: 1 bottle), flow rate 1.0 ml
/ Min, elution solvent tetrahydrofuran, column temperature 40 ° C
GPC measurement was performed under the following analysis conditions, and the values were determined by conversion with standard polystyrene.

[0023]

The present invention will be described below with reference to examples. The present invention is not limited by these examples,
"Parts" and "%" described in Examples and Comparative Examples
Represents "parts by weight" and "% by weight".

Production Example 1 Xylene / formaldehyde resin (Mitsubishi Gas Chemical Co., Ltd.)
A mixture of 30 parts of Nicanol G), 90 parts of resorcinol, 30 parts of methyl isobutyl ketone, and 0.1 part of paratoluenesulfonic acid was gradually heated and reacted at 100 ° C. for 2 hours. Then, 22 parts of a 37% aqueous formaldehyde solution were gradually added. And reacted at 100 ° C. for 1 hour. To this was added 110 parts of methyl isobutyl ketone to form a homogeneous solution, 100 parts of ion-exchanged water was added, and the mixture was stirred for 10 minutes and allowed to stand to separate into an organic layer and an aqueous layer. Of these, the aqueous layer was removed, and ionic impurities were removed outside the system. In the subsequent distillation step, condensed water, unreacted resorcin, and the like are removed to obtain 80 parts of a phenol / alkylbenzene / aldehyde resin having a hydroxyl equivalent of 92 g / eq, a softening point of 88 ° C., a solution viscosity of 37 μm ² / s, and a weight average molecular weight of 1150. I got

Production Example 2 Xylene / formaldehyde resin (Mitsubishi Gas Chemical Co., Ltd.)
A mixture of 30 parts of Nicanol G), 60 parts of resorcin, 40 parts of phenol, and 0.1 part of paratoluenesulfonic acid was reacted in the same manner as in Example 1 to obtain a hydroxyl equivalent of 112 g.
/ Eq, a softening point of 86 ° C., a solution viscosity of 33 μm ² / s, and 94 parts of a phenol-alkylbenzene-aldehyde resin having a weight average molecular weight of 980 were obtained.

Production Example 3 Xylene / formaldehyde resin (Mitsubishi Gas Chemical Co., Ltd.)
Nicanol G) 35 parts, catechol 20 parts, orthocresol 80 parts, and paratoluenesulfonic acid 0.1
Part of the mixture was reacted in the same manner as in Example 1 to give a hydroxyl equivalent of 1
30 g / eq, softening point 85 ° C., solution viscosity 42 μm ² /
As a result, 110 parts of a phenol / alkylbenzene / aldehyde resin having a weight average molecular weight of 1270 was obtained.

Comparative Production Example 1 Xylene / formaldehyde resin (Mitsubishi Gas Chemical Co., Ltd.)
A mixture of 100 parts of Nicanol G), 10 parts of resorcinol, 20 parts of methyl isobutyl ketone, and 0.1 part of paratoluenesulfonic acid was reacted in the same manner as in Example 1 to obtain a hydroxyl equivalent of 160 g / eq, a softening point of 127 ° C, Solution viscosity 96
99 parts of a phenol / alkylbenzene / aldehyde resin having a μm ² / s and a weight average molecular weight of 3150 were obtained.

Comparative Production Example 2 Xylene / formaldehyde resin (Mitsubishi Gas Chemical Co., Ltd.)
A mixture of 3 parts of Nicanol G), 70 parts of resorcinol, 30 parts of hydroquinone, 30 parts of methyl isobutyl ketone, and 0.1 part of paratoluenesulfonic acid was reacted in the same manner as in Example 1 to obtain a hydroxyl equivalent of 68 g / eq, softening. Point 59
° C., a solution viscosity 24μm ² / s, to obtain a 55 parts phenol alkylbenzene aldehyde resin having a weight average molecular weight 380.

Comparative Production Example 3 A mixture of 188 parts of phenol, 121 parts of 37% formalin and 0.5 part of 35% hydrochloric acid was reacted at 100 ° C. for 2 hours, and then distilled under reduced pressure until the internal temperature reached 170 ° C. Removal of water and unreacted phenol, hydroxyl equivalent 104g / e
q, 190 parts of a phenol resin having a softening point of 110 ° C., a solution viscosity of 88 μm ² / s and a weight average molecular weight of 2910 were obtained.

Examples 1 to 5 and Comparative Examples 1 to 4 Phenols, alkylbenzenes and aldehyde resins obtained in Production Examples 1 to 3 and Comparative Production Examples 1 and 2, Comparative Production Example 3
Phenolic resin obtained from
-Xylene glycol dimethyl ether polycondensate (XL-225LL, manufactured by Mitsui Toatsu Co., Ltd.) and orthocresol type epoxy resin (EOCN-1020-6, manufactured by Nippon Kayaku)
5) Roll-kneading 2-methylimidazole, fused silica and stearic acid with the composition shown in Table 1 and adding 100 kg / c
Press molding was performed at m ² at 175 ° C. for 10 minutes, and post-curing was further performed at 180 ° C. for 6 hours to obtain a cured molded product. Table 1 shows the results of measuring the glass transition temperature, flexural strength, flexural modulus and water absorption of this molded product.

[0031]

[Table 1]

[0032]

As is clear from Table 1, the epoxy resin molded product using the epoxy resin curing agent of the present invention has excellent heat resistance and has a low flexural modulus and a low water absorption without a decrease in flexural strength. It is greatly reduced and has low stress and excellent moisture resistance. Further, the epoxy resin curing agent of the present invention is suitable for epoxy resin encapsulating materials for high-performance electronic components, epoxy resin powder coatings, epoxy resin laminates, and the like, and greatly contributes to improving the performance of electronic components. Be expected.

Claims (3)

[Claims] 1. An alkylbenzene (X) represented by the general formula (1) and an aldehyde (Y) represented by the general formula (2)
Alkylbenzene obtained by reacting 1) in the presence of an acid catalyst;
The weight ratio of the aldehyde resin (A) and the phenols (Z) represented by the general formula (3) or (3) and (4) is 1
After polycondensation in the presence of an acid catalyst at ≦ (Z) / (A) ≦ 20, the aldehyde (Y2) further represented by the general formula (2)
An epoxy resin curing agent containing phenol, alkylbenzene and aldehyde resins as the main component. Embedded image (In the formula, R ₁ represents an alkyl group having 1 to 8 carbon atoms, which may be the same or different, and m is an integer of 1 to 4.) R ₂ —CHO (2) ( In the formula, R ₂ represents hydrogen or a monovalent hydrocarbon group having 1 to 7 carbon atoms.Y 1 and Y 2 may be the same or different from each other.) Embedded image (In the formula, R ₃ represents an atom or a group selected from hydrogen, an alkyl group having 1 to 8 carbon atoms, an alkenyl group, and a halogen, which may be the same or different. Is an integer of 1 to 3.) 2. A phenol / alkylbenzene / aldehyde resin having a hydroxyl equivalent of 70 to 150 g / eq, a softening point of 60 to 120 ° C., a solution viscosity of 20 to 90 μm ² / s,
The epoxy resin curing agent according to claim 1, having a weight average molecular weight of 400 to 3000. 3. The epoxy resin curing according to claim 1, wherein the alkylbenzenes (X) are m-xylene, the aldehydes (Y1, Y2) are both formaldehyde, and the phenols (Z) are resorcinol. Agent.