JP3152701B2 - Epoxy resin curing agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin curing agent which exhibits good curability when cured with an epoxy resin, and gives a cured product having excellent heat resistance, low stress and excellent moisture resistance.

[0002]

2. Description of the Related Art Conventionally, for sealing electronic parts such as transistors and integrated circuits, inorganic fillers such as ortho-cresol novolak epoxy resin and / or phenol novolak epoxy resin novolak type phenol resin hardener, silica powder and the like have been used. An epoxy resin sealing material composed of other additives and the like is used. However, in recent years,
With the increase in the degree of integration of integrated circuits, the size of chips has been increased, the mounting method has changed from insertion mounting 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 where it is sealed in a thin package, the problem of package cracks occurs, and the sealing material is required to further improve heat resistance, reduce stress, and improve moisture resistance. Have been.

[0003] To improve the heat resistance of the encapsulant, a maleimide resin is being studied in place of the epoxy resin. However, although the heat resistance is improved, the water absorption rate is increased and it is satisfactory as a sealant for electronic parts. Has not been obtained. Further, in order to reduce the stress and improve the moisture resistance of the epoxy resin encapsulant, a xylene-modified phenol resin is used as a curing agent (Japanese Patent Laid-Open No.
No. 9-105017), use of a fluorinated novolak (JP-A-64-74215), use of a phenol-dicyclopentadiene resin (JP-A-62-10483).
No. 0) has been considered. However, these are
Even if the stress is reduced, the strength is also reduced, or even if the moisture resistance is improved, the curing with the epoxy resin is slow and the moldability of the encapsulant is poor, and all are cured for the epoxy resin encapsulant The agent was not satisfactory enough.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an epoxy resin curing agent which provides a cured product having excellent heat resistance, low stress and excellent moisture resistance without deteriorating curability in curing with an epoxy resin. To provide.

[0005]

SUMMARY OF THE INVENTION The present invention is an epoxy resin curing agent containing an aromatic hydrocarbon-modified phenol resin as a main component, obtained by reacting the following components (a) and (b) with an acid catalyst. (A) at least one kind selected from bisphenol A, bisphenol S and cyclohexylidene diphenol; and (b) at least one kind of aromatic hydrocarbon having a substituent, obtained by reacting with formaldehyde in the presence of an acid catalyst. At least one of aromatic hydrocarbon and formaldehyde resins.

The component (a) used in the present invention is represented by the formulas (1) to ( 3 ) and has two hydroxyl groups per molecule which can react with the epoxy resin.

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As the component (a), only one selected from these may be reacted with the component (b), or a mixture of two or more may be reacted with the component (b). By reacting any of the compounds represented by the formulas 1 to 3 with the component (b), an ethoxy resin curing agent having good properties aimed at by the present invention can be obtained. When the epoxy resin is cured with the curing agent obtained from the above, a cured product having the following characteristics can be obtained. That is, when bisphenol A is used, a cured product having a small moisture absorption is obtained,
When bisphenol S is used, a cured product having a high glass transition point is obtained, and when cyclohexylidenediphenol is used, a cured product having a small moisture absorption and a low elastic modulus is obtained.

[0008] The aromatic hydrocarbon / formaldehyde resin used as the component (b) of the present invention is composed of at least one aromatic hydrocarbon having a substituent such as toluene, xylene, mesitylene, ethylbenzene and methylnaphthalene and formaldehyde. After reacting in the presence of an acid catalyst,
It is manufactured by neutralizing and washing to remove diallylmethanes and other low-boiling fractions under reduced pressure.
A xylene-formaldehyde resin and a mesitylene-formaldehyde resin are preferred from the viewpoint of high reactivity with the component (a).

The aromatic hydrocarbon-modified phenolic resin is prepared by mixing the components (a) and (b) in the presence of an acid catalyst in the range of 80 to 20.
After reacting at 0 ° C. for 1 to 10 hours, it is obtained by removing the condensed water generated by distillation under reduced pressure or normal pressure. As the acid catalyst, organic acids such as oxalic acid, paratoluenesulfonic acid, xylenesulfonic acid, and phenolsulfonic acid, and inorganic acids such as hydrochloric acid and sulfuric acid can be used.

[0010]

The epoxy resin curing agent of the present invention containing an aromatic hydrocarbon-modified phenol resin as a main component gives a cured product having excellent heat resistance, low stress and excellent moisture resistance by curing with an epoxy resin. This is thought to be due to the epoxy resin curing agent of the present invention being modified with an aromatic hydrocarbon.
Furthermore, the phenols used as the component (a) have internuclear bonding groups not found in ordinary phenol resins, and these have good effects on improving heat resistance, reducing stress, and reducing water absorption. Conceivable.

[0011]

The present invention will be described below with reference to examples, but the present invention is not limited to these examples. “Parts” and “%” described herein indicate “parts by weight” and “% by weight”. (Production Example 1) 130 parts of bisphenol A, xylene / formaldehyde resin (Nicanol H manufactured by Mitsubishi Gas Chemical) 7
0 parts, a mixture of 30 parts of mesitylene-formaldehyde resin (Nicanol M, manufactured by Mitsubishi Gas Chemical) and 2.3 parts of p-toluenesulfonic acid are gradually heated, and after refluxing, the mixture is reacted under reflux for 5 hours and then formed by a condensation reaction. The water thus obtained was removed by distillation to obtain 205 parts of a xylene / mesitylene-modified phenol resin having a softening point of 121 ° C.

(Production Example 2) 84 parts of cyclohexylidene diphenol, 75 parts of bisphenol A xylene / formaldehyde resin (Nickanol H, manufactured by Mitsubishi Gas Chemical) 100
In the same manner as in Production Example 1, 238 parts of a xylene-modified phenol resin having a softening point of 118 ° C. was obtained using a mixture of 5 parts of oxalic acid and 5 parts of oxalic acid.

(Production Example 3) A mixture of 65 parts of biphenol, 80 parts of bisphenol A, 100 parts of mesitylene / formaldehyde resin (Nicanol M manufactured by Mitsubishi Gas Chemical) and 1.3 parts of sulfuric acid was prepared in the same manner as in Production Example 1 to have a softening point of 122.
There was obtained 225 parts of a mesitylene-modified phenol resin at ℃.

(Production Example 4) A mixture of 44 parts of bisphenol S, 120 parts of bisphenol A, 100 parts of mesitylene / formaldehyde resin (Nickanol M manufactured by Mitsubishi Gas Chemical) and 2.6 parts of paratoluenesulfonic acid was softened in the same manner as in Production Example 1. 243 parts of a mesitylene-modified phenol resin having a point of 119 ° C. were obtained.

(Production Example 5) 188 parts of phenol, 37%
After reacting a mixture of 121.6 parts of formalin and 0.5 part of 35% hydrochloric acid at 100 ° C. for 2 hours, the internal temperature was 170 ° C. under reduced pressure.
Water and phenol were removed by distillation until the temperature reached ° C, and 191 parts of a phenol resin having a softening point of 110 ° C was obtained.

Examples 1-4 and Comparative Examples Production Examples 1
4 or the phenol resin obtained in Production Example 5, an ortho-cresol novolak-type epoxy resin (EOCN-1 manufactured by Nippon Kayaku)
020-65), 2-methylimidazole, fused silica and stearic acid were roll-kneaded in the composition shown in the table, and 100
Press molding was performed under the conditions of kg / cm 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. The glass transition temperature, flexural strength, flexural modulus and water absorption of the molded product were measured, and the results are shown in Table 1.

[0017]

[Table 1]

[0018]

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 a large flexural modulus and a high water absorption without lowering the flexural strength. It is suitable for use as an epoxy resin sealing material for electronic components, an epoxy resin powder coating material, and an epoxy resin curing agent for epoxy resin laminates.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-60-139749 (JP, A) JP-A-59-226066 (JP, A) JP-A-59-8718 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) C08G 59/62 C08G 14/04

Claims (1)

(57) [Claims] 1. An epoxy resin curing agent containing an aromatic hydrocarbon-modified phenol resin as a main component, obtained by reacting the following components (a) and (b) with an acid catalyst. (A) one or more compounds selected from bisphenol A, bisphenol S and cyclohexylidene diphenol, and (b) one or more compounds having an aromatic hydrocarbon having a substituent, which are reacted with formaldehyde in the presence of an acid catalyst. Aromatic hydrocarbon and formaldehyde resin.