JP2009062447A - Liquid epoxy resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid epoxy resin composition having a low viscosity, little in viscosity changes and excellent in the balance of curability and storage stability. <P>SOLUTION: The liquid epoxy resin composition contains (a) a liquid epoxy resin, (b) an aromatic amine curing agent, and (c), as a curing accelerator, a phosphonium compound represented by general formula (1) [wherein R<SB>1</SB>-R<SB>4</SB>, which may be identical or different, indicate each a 1-16C linear or branched alkyl group; and X indicates an anionic residue of a 2-16C aliphatic monocarboxylic acid]. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid epoxy resin composition.

  Conventionally, liquid epoxy resin-based compositions have excellent mechanical, chemical and electrical properties, so various electrical components such as coils, capacitors, printed circuit boards, etc. in the form of adhesives, paints or cast materials, Widely used in applications such as insulating sealing of semiconductor elements and integrated circuits.

  In recent years, there has been a demand for a liquid epoxy resin composition having a low viscosity and a small viscosity change, and many liquid epoxy resin compositions composed mainly of a liquid epoxy resin / aromatic amine curing agent have been proposed. .

However, in the above liquid epoxy resin composition, imidazoles are used as curing accelerators in order to shorten the curing time (see Patent Documents 1 and 2), but the storage stability at room temperature is poor. There were drawbacks. Therefore, for the purpose of improving the storage stability, a technique of using imidazoles in a microencapsulated form is also known (see Patent Document 3). However, an encapsulation process is required, and capsule components remain as foreign substances. A new problem has arisen. In addition, for the purpose of improving pot life (usable time), it has been proposed to use boron trifluoride / piperidine complex or the like as a curing accelerator (see Patent Document 4), but it has storage stability at room temperature. There was a drawback of being bad.
JP 2006-233127 A JP 2007-023272 A JP-A-2005-350618 JP 2006-265434 A

  The present invention has been made in view of the above-described conventional drawbacks, and an object of the present invention is to provide a liquid epoxy resin composition having a low viscosity, a small viscosity change, and an excellent balance between curability and storage stability at room temperature. It is said.

  As a result of intensive studies to solve the above problems, the present inventors have blended a specific phosphonium compound as a curing accelerator with a composition containing a liquid epoxy resin and an aromatic amine-based curing agent as components. In this case, it was found that a liquid epoxy resin composition excellent in balance between curability and storage stability at room temperature was obtained, and the present invention was completed.

［式中、Ｒ_１〜Ｒ_４は、同一又は異なって、炭素数１〜１６の直鎖状若しくは分岐鎖状のアルキル基を示し、Ｘは炭素数２〜１６の脂肪族モノカルボン酸のアニオン残基を示す。］
で表されるホスホニウム化合物を含む液状エポキシ樹脂系組成物を構成している。 That is, the gist of the present invention is as follows.
(A) liquid epoxy resin,
As the (b) aromatic amine-based curing agent and (c) the curing accelerator, the following general formula (1)

[Wherein, R _{1 to} R ₄ are the same or different and each represents a linear or branched alkyl group having 1 to 16 carbon atoms, and X is an anion of an aliphatic monocarboxylic acid having 2 to 16 carbon atoms. Indicates residue. ]
The liquid epoxy resin type composition containing the phosphonium compound represented by these is comprised.

  In the liquid epoxy resin-based composition of the present invention, an effect of low viscosity and small viscosity change and excellent balance between curability and storage stability at room temperature can be obtained.

Hereinafter, the present invention will be described in detail.
The liquid epoxy resin composition of the present invention is a composition comprising a liquid epoxy resin, an aromatic amine curing agent, and a phosphonium compound represented by the above general formula (1).

<Liquid epoxy resin>
As the epoxy resin, a liquid epoxy resin containing two or more epoxy groups in the molecule can be used without limitation. Examples thereof include bisphenol A type epoxy resin, bisphenol AD type epoxy resin, bisphenol F type epoxy resin, glycidylamine type epoxy resin, and alicyclic epoxy resin.
An epoxy resin can be used individually or in mixture of 2 or more types.

<Aromatic amine curing agent>
Examples of the aromatic amine curing agent include diethyl toluenediamines, bis (methylthio) toluenediamines, polyoxytetramethylene bis (p-aminobenzoate) s, and the like.
The content of the aromatic amine curing agent is preferably such that the equivalent ratio of the epoxy equivalent of the epoxy resin and the amine equivalent of the aromatic amine curing agent is about 0.8 to 1.2. If it is the said range, hardening reaction will fully advance.

［式中、Ｒ_１〜Ｒ_４は、同一又は異なって、炭素数１〜１６の直鎖状若しくは分岐鎖状のアルキル基を示し、Ｘは炭素数２〜１６の脂肪族モノカルボン酸のアニオン残基を示す。］
で表される化合物が硬化促進剤として含まれる。
一般式（１）で表される化合物は、単独で又は２種以上を組み合わせて使用することができる。
一般式（１）で表される化合物の含有量は、エポキシ樹脂１００重量部に対して、１〜６重量部程度が好ましく、３〜５重量部程度がより好ましい。上記範囲であれば、十分な硬化速度が得られ、かつ室温での保存安定性が優れている。
なお、上記硬化促進剤は公知物質であり、特開昭６３−１９０８９３号公報に記載されている方法により合成でき、例えば、対応するテトラアルキルホスホニウムヒドロキシドにカルボン酸を反応させることにより容易に合成することができる。 <Curing accelerator>
The following general formula (1)

[Wherein R _{1 to} R ₄ are the same or different and represent a linear or branched alkyl group having 1 to 16 carbon atoms, and X is an anion of an aliphatic monocarboxylic acid having 2 to 16 carbon atoms. Indicates residue. ]
Is included as a curing accelerator.
The compound represented by General formula (1) can be used individually or in combination of 2 or more types.
About 1-6 weight part is preferable with respect to 100 weight part of epoxy resins, and, as for content of the compound represented by General formula (1), about 3-5 weight part is more preferable. If it is the said range, sufficient hardening rate will be obtained and the storage stability at room temperature will be excellent.
The curing accelerator is a known substance and can be synthesized by the method described in JP-A-63-190893. For example, it can be easily synthesized by reacting a corresponding tetraalkylphosphonium hydroxide with a carboxylic acid. can do.

<Other ingredients>
In the present invention, various known inorganic fillers can be used to reduce the expansion coefficient. Examples thereof include fused silica, crystalline silica, alumina, and aluminum nitride. 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 type composition may be contained. Examples of the additive include an ion trap agent, a release agent, and a pigment such as carbon black.

<Liquid epoxy resin composition>
In order to prepare the liquid epoxy resin composition according to the present invention, an aromatic amine curing agent and a curing accelerator are first stirred and mixed under heating at a temperature of 20 to 80 ° C., and the resulting homogeneous mixture is obtained. It is desirable to carry out by adding a liquid epoxy resin and uniformly stirring and mixing at 20 to 80 ° C. in a vacuum kneader.
In addition, each component of these liquid epoxy resins, aromatic amine curing agents, and curing accelerators may be added at once, or may be added little by little in a plurality of times.
Other components such as silica and a release agent can be added and mixed at any time.

  Hereinafter, the usefulness of the present invention will be specifically described with reference to Examples and Test Examples, but the present invention is not limited thereto.

<Evaluation method>
1. Curing test (gelation test)
The curing rate of the liquid epoxy resin-based composition was measured by 175 ° C. gelation time (hot plate method).
The gelation tester used was GT-D manufactured by Nissin Kagaku.
2. Storage Stability Test A storage stability test was performed by measuring the viscosity of the liquid epoxy resin composition at room temperature (25 ° C.). The viscometer uses a coaxial double cylindrical rotary viscometer PM-2A manufactured by Malcolm, and the viscosity of the liquid epoxy resin composition is measured immediately after adjustment and after standing at room temperature (25 ° C.) for 24 hours. Storage stability was observed by viscosity change.

  JER Cure W (diethyltoluenediamine) of aromatic amine curing agent (amine equivalent 45, manufactured by Japan Epoxy Resin Co., Ltd.) 24.0 parts by weight (equivalent of amine equivalent in curing agent to epoxy equivalent in epoxy resin) 4.0 parts by weight of a curing accelerator, tetrabutylphosphonium decanoate, was added at 60 ° C. for 30 minutes, further stirred and dissolved, and then cooled to room temperature. To this was added 100.0 parts by weight of liquid epoxy resin jER828 (bisphenol A type epoxy resin) (epoxy equivalent 188, manufactured by Japan Epoxy Resin Co., Ltd.), and further mixed sufficiently to obtain a liquid epoxy resin composition.

  A liquid epoxy resin composition was obtained in the same manner as in Example 1 except that the curing accelerator tetrabutylphosphonium decanoate was changed to 3.0 parts by weight.

Comparative Example 1
Instead of tetrabutylphosphonium decanoate as a curing accelerator, 2-ethyl-
A liquid epoxy resin composition was obtained in the same manner as in Example 1, except that 3.0 parts by weight of 4-methylimidazole (manufactured by Wako Pure Chemical Industries, Ltd.) was used.

Comparative Example 2
A liquid epoxy resin composition in the same manner as in Example 1, except that 4.0 parts by weight of boron trifluoride / piperidine complex (manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of tetrabutylphosphonium decanoate as a curing accelerator. I got a thing.

About the liquid epoxy resin-type composition of Examples 1-2 and Comparative Examples 1-2, the gelatinization time and the viscosity measurement were performed. The results are shown in Table 1.

  As shown in Examples 1 and 2 in Table 1, the liquid epoxy resin composition of the present invention can adjust the curing rate (175 ° C. gelation time) by increasing or decreasing the blending amount of the curing accelerator, and In any case, excellent storage stability is exhibited (viscosity change after 24 hours at room temperature is smaller than in the comparative example). On the other hand, in Comparative Examples 1-2, the curing rate is between Example 1 and Example 2, but the storage stability is significantly inferior in any case.

  The liquid epoxy resin composition of the present invention has an excellent balance between curability and storage stability, and has a low viscosity, so that it is useful for delicate resin sealing of various small electric / electronic parts and semiconductor parts. .

Claims (2)

(A) liquid epoxy resin,
As the (b) aromatic amine curing agent and (c) curing accelerator, the following general formula (1)

[Wherein, R _{1 to} R ₄ are the same or different and each represents a linear or branched alkyl group having 1 to 16 carbon atoms, and X is an anion of an aliphatic monocarboxylic acid having 2 to 16 carbon atoms. Indicates residue. ]
The liquid epoxy resin type composition containing the phosphonium compound represented by these. In the general formula (1), all of R _{1 to} R ₄ are butyl groups, and X is a decanoate anion.