JP2014005382A - Epoxy resin composition and cured product thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin composition, which is suitable for many applications, including for power semiconductors, and gives a cured product improved in both thermostability and moisture resistance reliability, while having storage stability and quick curability contributing to improvement in work efficiency.SOLUTION: An epoxy resin composition at least contains a naphthalene type tetrafunctional epoxy resin of the following formula (1), a curing agent, and a phosphorus-based curing accelerator including one or more triarylphosphine triphenylborane adduct.

Description

  The present invention relates to an epoxy resin composition having both storage stability and fast curability while achieving both high heat resistance and high moisture resistance reliability of a cured product.

  In recent years, in the field of power devices (power control conversion semiconductors, hereinafter referred to as power semiconductors), the performance of silicon (Si) as a power semiconductor material has reached its limit, and silicon carbide (SiC) as a next-generation power semiconductor material And gallium nitride (GaN) have begun to be used (see Patent Document 1). As a result, these next-generation power semiconductor encapsulating resins have higher performance in terms of high heat resistance (heat resistance that can withstand high temperatures over 200 ° C for a long time), low expansion, high thermal conductivity, and high humidity resistance. Improvement is required (see Non-Patent Documents 1 and 2). In order to meet this demand, high performance of individual materials such as epoxy resins and curing agents is also expected in epoxy resin compositions that have been used conventionally.

  In addition, while high performance is expected for individual materials of epoxy resin composition, it is excellent in storage stability at room temperature after preparation to improve work efficiency in the field, and curing progresses quickly upon heating. There has also been a demand for development of an epoxy resin composition (see Non-Patent Document 3).

  Under such circumstances, by paying attention to the epoxy resin curing accelerator and using a specific phosphorus curing accelerator, a cured product having excellent heat resistance and moisture resistance reliability can be obtained, and at the same time, an epoxy having excellent quick curing properties. Resin compositions have been reported (see Non-Patent Documents 4 and 5).

  However, the epoxy resin composition is insufficient in terms of stability of the composition at room temperature storage (hereinafter referred to as storage stability), and the glass transition temperature of the cured resin is 140 ° C. in heat resistance. This is not suitable for power semiconductor applications.

  As a method for solving these individual problems, there is an example (see Patent Documents 2 and 3) using an imidazole compound as a curing accelerator for the purpose of achieving both storage stability and fast curability. In these cases, There is a concern that the hydrolyzable chlorine in the epoxy resin is pulled out by imidazole, and the moisture resistance reliability such as corrosion of the semiconductor circuit and metal wiring due to the extracted chloride ions is concerned.

Moreover, following formula (1)

There has been proposed a resin composition capable of obtaining a cured resin having high heat resistance by using a naphthalene-type tetrafunctional epoxy resin represented by (see Non-Patent Document 6). However, a cured product using the epoxy resin has not been known which has high heat resistance, high moisture resistance reliability, storage stability of the resin composition, and fast curing property.

Furthermore, the following general formula (2)

Among the triarylphosphine triphenylborane adducts represented by general formula (I), compounds in which R is —H and —CH ₃ are known, and are used as phosphorus-based curing accelerators for laminates and the like (Patent Document 4). Until now, there has been no example in which the above formula (2) is used as a curing accelerator for epoxy resins in power semiconductor applications from the viewpoint of heat resistance and moisture resistance reliability.

JP 2009-272482 A JP 2011-86669 A JP 2004-346247 A JP-A-6-322073 JP-A-9-087367 JP 2006-290949 A

“High-performance device sealing technology and cutting-edge materials”, published by CMC Publishing, p. 101-113 (2009) “Network Polymer”, Vol. 33, No. 1, published by the Synthetic Resin Industry Association, p. 34-41 (2012) "Advanced Semiconductor Package Material Technology", published by Technical Information Association, p. 38 (2010) A summary of the 61st Network Polymer Lecture Discussion Meeting, published by the Japan Plastics Industry Association, p. 143 (2010) “Network Polymer”, Vol. 33, No. 3, published by Synthetic Resin Industry Association, p. 123-129 (2012) "Special Epoxy Resin Technology Association Special Lecture Diverse High Performance Epoxy Resin Adapted to Various Applications" Lecture Summary (2009)

  The present invention provides a cured product having both high heat resistance and high humidity resistance, which is suitable for many applications including power semiconductor applications, while at the same time providing storage stability and speed that contribute to improvement of work efficiency. It aims at providing the epoxy resin composition which has sclerosis | hardenability.

  In view of such a situation, the present inventors have intensively studied in order to achieve the above-described problems. As a result, by blending an epoxy resin represented by the following formula (1), a curing agent, and a phosphorus curing accelerator represented by the following general formula (2), it is excellent in high heat resistance and high moisture resistance reliability. The present invention was completed by finding that the cured product can be obtained, and that the resin composition itself has achieved both storage stability and fast curability.

で表されるナフタレン型４官能エポキシ樹脂を少なくとも含むエポキシ樹脂
（Ｂ）硬化剤
（Ｃ）下記一般式（２）

〔式中、Ｒは、−Ｈ、−ＣＨ_３、炭素数２〜１６の直鎖状もしくは分岐鎖状のアルキル基を示す〕で表されるトリアリールホスフィントリフェニルボラン付加体を１種類または２種類以上を少なくとも含むリン系硬化促進剤
〔２〕硬化剤が、フェノール樹脂であることを特徴とする〔１〕に記載のエポキシ樹脂組成物。
〔３〕さらに、無機充填剤として、溶融シリカ、クレー、マイカ、炭酸カルシウム、アルミナ、窒化ホウ素、窒化アルミニウムから選択される１種類または２種類以上を含有することを特徴とする〔１〕もしくは〔２〕に記載のエポキシ樹脂組成物。
〔４〕〔１〕〜〔３〕のいずれかに記載のエポキシ樹脂組成物を硬化して得られるエポキシ樹脂硬化物。 That is, the present invention is as follows.
[1] An epoxy resin composition containing at least the following components (A), (B), and (C).
(A) The following formula (1)

An epoxy resin containing at least a naphthalene-type tetrafunctional epoxy resin represented by formula (B) Curing agent (C)

[Wherein R represents —H, —CH ₃ , a linear or branched alkyl group having 2 to 16 carbon atoms], or one or two triarylphosphine triphenylborane adducts represented by The epoxy resin composition according to [1], wherein the phosphorus-based curing accelerator [2] containing at least one kind is a phenol resin.
[3] Furthermore, the inorganic filler contains one or more selected from fused silica, clay, mica, calcium carbonate, alumina, boron nitride, aluminum nitride [1] or [1] 2].
[4] A cured epoxy resin obtained by curing the epoxy resin composition according to any one of [1] to [3].

  Since the epoxy resin composition of the present invention can obtain a cured product having high heat resistance and high moisture resistance reliability, it can be used in many applications including next-generation power semiconductor applications and is extremely useful. is there. Furthermore, the resin composition itself can realize both storage stability and fast curability, and has high work convenience.

Hereinafter, the present invention will be described in detail.
The present invention is (A) an epoxy resin, (B) a curing agent, (C) an epoxy resin composition containing a phosphorus-based curing accelerator, and a cured product thereof.

  In the present invention, the epoxy resin composition refers to a mixture obtained by uniformly mixing the (A) epoxy resin, (B) curing agent, and (C) phosphorus curing accelerator, and the epoxy resin cured product is an epoxy resin. By applying heat to the composition under certain conditions, the epoxy resin loses its fluidity and refers to a solid that has been cured.

<Resin composition>
(A) Epoxy resin As an epoxy resin, the naphthalene type | mold tetrafunctional epoxy resin represented by following formula (1) is preferable.

  This is because when the epoxy resin is used, a highly heat-resistant cured product and a fast-curing composition can be obtained. Furthermore, other epoxy resins containing two or more epoxy groups, for example, naphthalene type epoxy resins other than the specific structure represented by the formula (1), phenol novolac type epoxy resins, within a range not impairing the effects of the present invention, A cresol novolac type epoxy resin, a biphenyl type epoxy resin, a biphenyl aralkyl type epoxy resin, a bisphenol A type epoxy resin, or a bisphenol F type epoxy resin may be used alone or in combination.

(B) Curing agent The curing agent is not particularly limited, and various known ones can be used. For example, polyfunctional phenol resins such as dicyandiamide, diamidediphenylmethane, diaminodiphenylsulfone, phthalic anhydride, pyromellitic anhydride, novolac phenol, cresol novolac phenol, aralkyl phenol, biphenyl phenol, dicyclopentadiene, etc. Can be mentioned. Several types of these curing agents can be used in combination. In order to improve heat resistance, it is preferable to use a phenol resin.

Among these, a novolac type phenol resin represented by the following formula (3) is preferable.

  The blending amount of the phenol resin curing agent is determined in consideration of the equivalent ratio of the epoxy equivalent in the epoxy resin and the hydroxyl equivalent of the phenol resin. Generally, the content is determined so that the equivalent ratio of epoxy equivalent to hydroxyl equivalent is 1: 0.1 to 1.5, more preferably 1: 0.7 to 1.2.

〔式中、Ｒは、−Ｈ、−ＣＨ_３、炭素数２〜１６の直鎖状もしくは分岐鎖状のアルキル基を示す〕 (C) Curing accelerator As the curing accelerator, a phosphorus curing accelerator obtained by adding triphenylborane to a triarylphosphine represented by the following general formula (2) can be used.

[Wherein, R represents —H, —CH ₃ , a linear or branched alkyl group having 2 to 16 carbon atoms]

  Examples of the linear or branched alkyl group having 2 to 16 carbon atoms represented by R include ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl. Group, n-pentyl group, isopentyl group, 2-methylbutyl group, neopentyl group, n-hexyl group, 4-methylpentyl group, 3-methylpentyl group, 2-methylpentyl group, 3,3-dimethylbutyl group, 1 , 3-dimethylbutyl group, 2,3-dimethylbutyl group, 1-ethylbutyl group, 1-methyl-1-ethylpropyl group, 1,2-dimethylbutyl group, 2-methyl-1-ethylpropyl group, 2, Examples include 2-dimethylbutyl group. More preferred are triphenylphosphine triphenylborane (TPP-S) and tri (p-tolyl) phosphine triphenylborane (TPTP-S), where R is hydrogen or a methyl group.

  It is preferable that the compounding quantity of the hardening accelerator of an epoxy resin composition is 0.5-5 weight part with respect to 100 weight part of epoxy resins. This is because if the content is less than 0.5 parts by weight, the curing accelerating effect may not be sufficiently exhibited, and if the content is more than 5 parts by weight, the curing accelerating performance is not improved. Considering the curing acceleration effect more strictly, the content is more preferably 1 to 3 parts by weight.

  By blending the resin compositions (A) to (C) of the present invention, a cured product excellent in high heat resistance and high moisture resistance reliability can be obtained. Furthermore, the resin composition itself has storage stability and fast curing. It is possible to realize compatibility of sex.

(D) Inorganic fillers Various known inorganic fillers can be added to the epoxy resin composition of the present invention. Addition of inorganic fillers has the effect of reducing expansion coefficient or improving thermal conductivity, mechanical strength and thixotropy. For example, fused silica, crystalline silica, clay, mica, calcium carbonate, alumina, nitriding Examples thereof include boron, aluminum nitride, beads formed by spheroidizing them, and glass fibers.

  Furthermore, they may be surface treated with a coupling agent such as a silane coupling agent. In addition, the well-known additive added to an epoxy resin composition may be contained. Examples of the additive include an ion trap agent, a release agent, and a pigment such as carbon black.

<Method for producing resin composition>
Hereinafter, the manufacturing method of the epoxy resin composition concerning this invention is demonstrated.
First, a mixture of a curing agent and a curing accelerator is heated and then cooled, then mixed with an epoxy resin, heated and then cooled.

  The reason why the mixture of the curing agent and the phosphorus curing accelerator is heated is to facilitate the mixing by reducing the viscosity of the curing agent, and to stir the curing agent and the phosphorus curing accelerator to be uniform. . Here, if the heating temperature is preferably 100 ° C. to 180 ° C., it can be easily mixed. The reason for pre-cooling the mixture before mixing with the epoxy resin is that it is necessary to accurately weigh the mixture so that the equivalent ratio of epoxy equivalent to hydroxyl equivalent is 1: 1, This is for easy handling.

  The mixture of the cooled hardening | curing agent and phosphorus hardening accelerator, and an epoxy resin are mixed, and it is heated after setting it as an epoxy resin composition. Accordingly, the curing agent and the epoxy resin are reaction-cured by the action of the phosphorus-based curing accelerator. Then, an epoxy resin hardened material is obtained by cooling the obtained reaction hardened material. It is preferable to heat an epoxy resin composition on 100 to 250 degreeC conditions. This is because the reaction curing proceeds promptly. In addition, it is preferable to use a vacuum kneader when mixing the curing agent and the phosphorus-based curing accelerator or mixing with the epoxy resin because it is easy to uniformly stir and mix.

  In addition, each component of these hardening | curing agents, a phosphorus hardening accelerator, and an epoxy resin may be mixed at once in each mixing process, or may be mixed little by little in several steps. Similarly, when the above-mentioned solvent, additive, inorganic filler, and the like are mixed, they can be mixed once or divided into a plurality of times at an arbitrary time.

  Hereinafter, the present invention will be specifically described. However, the scope of the present invention is not limited by these examples.

<Example 1>
Phenolite TD-2131 (hydroxyl equivalent 104, softening point 78 ° C., manufactured by DIC Corporation) of phenol resin curing agent (phenol novolak type curing agent) 18.1 parts by weight as a phosphorus curing accelerator tri (p-tolyl) ) Add 0.35 parts by weight of phosphine triphenylborane (trade name TPTP-S, manufactured by Hokuko Chemical Co., Ltd.) (hereinafter referred to as TPTP-S), stir and mix with heating at 150 ° C. for 2 minutes, Until cooled. To this was added 30.0 parts by weight of naphthalene-type tetrafunctional epoxy resin EPICLON HP-4710 (epoxy equivalent 172, softening point 96 ° C., manufactured by DIC Corporation), and the mixture was stirred and mixed at 130 ° C. for 2 minutes with heating, followed by room temperature. The product was cooled to an epoxy resin composition. Here, the equivalent ratio of epoxy equivalent to hydroxyl equivalent is 1.0.
The resulting epoxy resin composition is cured at 150 ° C. for 1 hour, 200 ° C. for 2 hours, and 220 ° C. for 4 hours, and further cured as an after-cure at 250 ° C. for 2 hours to obtain a cured epoxy resin product. Obtained.

<Example 2>
Implemented except that instead of 0.35 part by weight of TPTP-S, 0.30 part by weight of triphenylphosphine triphenylborane (trade name TPP-S, manufactured by Hokuko Chemical Co., Ltd.) (hereinafter referred to as TPP-S) In the same manner as in Example 1, an epoxy resin composition and a cured epoxy resin were obtained.

<Comparative example 1>
Example 1 except that in place of 0.35 part by weight of TPTP-S, 0.20 part by weight of tri (p-tolyl) phosphine (trade name TPTP, manufactured by Hokuko Chemical Co., Ltd.) (hereinafter referred to as TPTP) is used. Similarly, an epoxy resin composition and a cured epoxy resin were obtained.

<Comparative example 2>
In place of 0.35 parts by weight of TPTP-S, epoxy was used in the same manner as in Example 1 except that 0.15 parts by weight of triphenylphosphine (made by Hokuko Chemical Co., Ltd., trade name TPP) (hereinafter referred to as TPP) was used. A resin composition and a cured epoxy resin were obtained.

<Comparative Example 3>
Example 1 except that in place of 0.35 parts by weight of TPTP-S, 2-ethyl-4-methylimidazole (trade name 2E4MZ, manufactured by Tokyo Chemical Industry Co., Ltd.) (hereinafter referred to as 2E4MZ) was 0.09 parts by weight. In the same manner as above, an epoxy resin composition and a cured epoxy resin were obtained.

<Comparative example 4>
Add 20.5 parts by weight of biphenylaralkyl-type curing agent MEH-7851M (hydroxyl equivalent 210, softening point 79 ° C., Meiwa Kasei Co., Ltd.) to 0.54 parts by weight of TPTP-S as a phosphorus curing accelerator at 150 ° C. The mixture was stirred and mixed with heating for 2 minutes, and then cooled to room temperature. To this, 28.0 parts by weight of biphenylaralkyl type epoxy resin NC-3000 (epoxy equivalent 275, softening point 57.1 ° C., manufactured by Nippon Kayaku Co., Ltd.) was added and stirred and mixed while heating at 130 ° C. for 1.5 minutes. Then, it was cooled to room temperature to obtain an epoxy resin composition. Here, the equivalent ratio of epoxy equivalent to hydroxyl equivalent is 1.0.
The obtained epoxy resin composition was cured at 150 ° C. for 2 hours and at 180 ° C. for 6 hours to obtain a cured epoxy resin.

<Comparative Example 5>
An epoxy resin composition and a cured epoxy resin were obtained in the same manner as in Comparative Example 4 except that 0.55 parts by weight of TPP-S was used instead of 0.50 parts by weight of TPTP-S.

<Comparative Example 6>
An epoxy resin composition and a cured epoxy resin were obtained in the same manner as in Comparative Example 4 except that TPTP was changed to 0.22 parts by weight instead of 0.50 parts by weight of TPTP-S.

<Comparative Example 7>
An epoxy resin composition and a cured epoxy resin were obtained in the same manner as in Comparative Example 4 except that TPP was changed to 0.20 parts by weight instead of 0.50 parts by weight of TPTP-S.

<Comparative Example 8>
An epoxy resin composition and a cured epoxy resin were obtained in the same manner as in Comparative Example 4 except that 2E4MZ was changed to 0.18 parts by weight instead of 0.50 parts by weight of TPTP-S.

  Next, the physical properties of the epoxy resin compositions and cured products obtained in Examples 1-2 and Comparative Examples 1-8 were confirmed by the methods shown below.

<Gel time measurement>
According to the gel time measurement method described in JIS K 6910, the gel time of the epoxy resin composition was measured at a steel plate temperature of 175 ° C. In this measurement, GT-D manufactured by Nisshin Kagaku Co., Ltd. was used as the gelation tester.

<Heat hardness measurement>
In accordance with the plastic durometer hardness test method described in JIS K 7215, the hot hardness of the epoxy resin composition was measured with a durometer over time. As the durometer, a durometer GS-720G manufactured by TECLOCK was used, and the epoxy resin composition was measured on a hot plate at 175 ° C.

<Heat resistance test>
A heat resistance test of the cured epoxy resin was performed. In this test, DMS6100 manufactured by SII Nano Technology was used as a dynamic viscoelasticity tester, and the temperature was raised at 5 ° C./min, the frequency was 1 Hz, and the bending mode was used. The glass transition temperature was the peak temperature of tan δ.

<Moisture resistance reliability test>
A moisture resistance reliability test of the cured epoxy resin was performed. As a moisture resistance reliability test method, first, ultrapure water and a cured resin product are placed in a double pressure vessel made of SUS / PTFE (HU-100, manufactured by Sanai Kagaku Co., Ltd.) and then placed in a small constant temperature tester to extract ions (120 C./100 hours), and after ion extraction, the amount of extracted ionic impurities was measured using an ion chromatograph (DX-320) manufactured by DIONEX. The amount of extracted chlorine ions (ppm) was calculated as the weight equivalent of the cured resin.

  Table 1 shows the composition of each example and the physical property test results.

  The cured epoxy resin shown in Examples 1 and 2 uses a naphthalene-type tetrafunctional epoxy resin as an epoxy resin and TPTP-S or TPP-S as a curing accelerator, and thus has a high glass transition temperature of 240 ° C. or higher. Further, after-curing, the glass transition temperature becomes 245 ° C. or more, so that the heat resistance is excellent, and since the amount of extracted chlorine ions is small, the moisture resistance reliability is also excellent.

  In addition, the epoxy resin compositions shown in Examples 1 and 2 were heated in the same manner as the compositions of Comparative Examples 1 to 3 using naphthalene type tetrafunctional epoxy resin as the epoxy resin and TPTP, TPP, and 2E4MZ as the curing accelerator. It is excellent in storage stability because the gel time does not change even when stored at 40 ° C., unlike the compositions of Comparative Examples 1 to 3, while ensuring fast curability from the confirmed increase in hardness. It is. That is, even if a naphthalene-type tetrafunctional epoxy resin is used as an epoxy resin, storage stability is poor unless TPTP-S or TPP-S is used as a curing accelerator.

  On the other hand, since the epoxy resin hardened | cured material concerning Comparative Examples 4-8 does not use the naphthalene type | mold tetrafunctional epoxy resin for an epoxy resin, regardless of the kind of hardening accelerator, a glass transition temperature is as low as 130-150 degreeC. Since it is inferior in heat resistance and hot hardness does not increase even after 450 seconds, it is inferior in fast curability.

  In Comparative Example 3, even though a naphthalene-type tetrafunctional epoxy resin is used as the epoxy resin, 2E4MZ is used as the curing agent, so that the moisture resistance is inferior and cannot be used for power semiconductor applications. Since it is inferior in storage stability, it does not contribute to improvement of work efficiency.

  From the above, the cured epoxy resin according to the examples is excellent in high heat resistance and high moisture resistance reliability, and is therefore suitable for many applications including power semiconductor applications, and the resin composition itself has storage stability and It can be seen that the convenience of work is high because both quick curing properties are achieved.

Claims (4)

An epoxy resin composition comprising at least the following components (A), (B), and (C).
(A) The following formula (1)

An epoxy resin containing at least a naphthalene-type tetrafunctional epoxy resin represented by formula (B) Curing agent (C)

[Wherein R represents —H, —CH ₃ , a linear or branched alkyl group having 2 to 16 carbon atoms], or one or two triarylphosphine triphenylborane adducts represented by Phosphoric curing accelerator containing at least one or more types The epoxy resin composition according to claim 1, wherein the curing agent is a phenol resin. The inorganic filler further contains one or more kinds selected from fused silica, crystalline silica, clay, mica, calcium carbonate, alumina, boron nitride, and aluminum nitride as essential components. Or the epoxy resin composition of 2. The epoxy resin hardened | cured material obtained by hardening | curing the epoxy resin composition in any one of Claims 1-3.