JP2009084384A - One-component epoxy resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a one-component epoxy resin composition excellent in airtightness, in particular, adhesiveness with engineering plastic and a metal terminal under a high temperature condition in reflow processing in a relay formed of the engineering plastic and excellent in storage stability. <P>SOLUTION: The one-component epoxy resin composition for insulation sealing of a small relay using engineering plastic as a part of the component or small electron-electric part comprises an epoxy resin A, a guanidine compound B, and a latent curing agent C as essential components, and 1-7 pts.wt. of the guanidine compound B is contained based on 100 pts.wt. of the epoxy resin A. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a one-component epoxy resin composition for hermetically sealing a small relay (hereinafter referred to as a relay) or insulatingly sealing a small electronic / electric part.

  With the development of the electronics industry, the production volume of relays has been growing steadily, and the fields used for communication equipment, OA equipment, home appliances, vending machines, etc. are diverse. In particular, the number of micro relays mounted on printed wiring boards is increasing. The necessary characteristics include prevention of solder flux intrusion, the ability to wash parts, or reduction of operation noise, maintenance of insulation between relay terminals in coastal areas, and airtightness maintenance after solder reflow. The demand for complete hermetic sealing with resin compositions is increasing, and the reliability requirements are becoming increasingly severe. In addition, with the trend toward miniaturization of electronic parts, relays have become smaller and the molding surface has been changed from polybutylene terephthalate (PBT), which is widely used as an engineering plastic used in case materials and body materials. A liquid crystal polymer (LCP) is used which has few burrs, is excellent in dimensional accuracy, and has excellent heat resistance that can cope with solder reflow. In recent years, polyamide resins (PA) having excellent heat resistance, low water absorption, slidability, chemical resistance, and the like may be used.

  Sealing materials used in such relays have strong airtightness after sealing, specifically, adhesion between engineering plastics such as LCP and metal terminals, and insulation sealing properties at the lead interface and case spacing. Required. However, conventionally used epoxy resin compositions have low heat resistance at the time of solder reflow treatment, and airtightness sometimes cannot be maintained.

  The conventional liquid epoxy resin composition includes a so-called so-called two-component epoxy resin composition in which a curing agent such as polyamidoamine and acid anhydride and an epoxy resin are mixed immediately before use, and a latent curing agent in advance as an epoxy resin. There are so-called so-called one-component epoxy resin compositions that are mixed with the composition. In general, the disadvantages of the two-pack type epoxy resin composition include poor curing due to measurement errors at the time of blending and short pot life after blending. When the curing agent is polyamide amine or aliphatic amine, the heat resistance of the resulting cured product is low, so the solder heat resistance after sealing is inferior, and in the case of acid anhydride, the curing temperature must be increased There is.

  Since the constituent members of the relay are mainly plastic materials other than terminal materials, coils, and magnets, a curing temperature of 120 ° C. or lower is desired. Plastic materials are becoming smaller and smaller in size as electronic components become smaller. Relays are becoming smaller, and polybutylene terephthalate (PBT), which is used in case materials and body materials, has less burrs on the molding surface, resulting in dimensional accuracy. A wholly aromatic polyester resin represented by LCP, which is excellent and has excellent heat resistance capable of handling solder reflow, is used. Further, dicyandiamide is often used as a latent curing agent for a one-pack type epoxy resin composition. However, when dicyandiamide is used in a one-part liquid epoxy resin composition for hermetically sealing or insulating sealing small electronic parts or electrical parts using a wholly aromatic polyester resin as a part of a constituent material, According to knowledge, the heat resistance of the obtained cured product was not sufficient. Therefore, a one-component liquid epoxy resin composition using an epoxy resin and a curing agent that does not contain dicyandiamide has been proposed to improve the adhesion between the wholly aromatic polyester resin and phosphor bronze at a high temperature in the solder reflow process. (Refer patent document 1) Moreover, when a solder reflow temperature is raised, since airtightness cannot be ensured, the one-pack type liquid epoxy resin composition containing a dicyandiamide is proposed. In recent years, since many components are mounted on a substrate, they are exposed to higher temperatures in order to increase the solder connection reliability. Furthermore, when double-sided mounting is used for high-density mounting, a reflow process is performed a plurality of times, so that a material satisfying both heat resistance and adhesiveness has been demanded.

JP 2001-207029 A Japanese Patent No. 3797616

  The present invention has been made as a result of various investigations in order to solve various problems in the one-pack type epoxy resin composition based on the conventional technology as described above.・ Excellent handling properties such as curability and workability, and excellent airtightness in relays made of engineering plastics such as LCP and PA, especially excellent adhesion to engineering plastics and metal terminals even at high temperatures in solder reflow processing. A liquid type liquid epoxy resin composition is provided.

Such an object is achieved by the following present inventions (1) to (5).
(1) Epoxy resin composition for insulating and sealing small relays or small electronic / electrical parts having engineering plastics as a component, epoxy resin (A), guanidine compound (B), potential A one-pack type epoxy resin composition comprising a curing agent (C) as an essential component and 1 to 7 parts by weight of a guanidine compound (B) per 100 parts by weight of the epoxy resin (A).
(2) The one-pack type epoxy resin composition according to the above (1), wherein the guanidine compound (B) is represented by the following structural formula.

上記一般式［１］中、Ｒは、水素、炭素数１〜６のアルキル基、炭素数５〜７のシクロアルキル基、または、下記構造式のいずれかを表す。ｍは１〜２の整数を示す。

In the general formula [1], R represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, or the following structural formula. m shows the integer of 1-2.

（前記構造式中、Ｘは、水素、炭素数１〜４のアルキル基、炭素数５〜７のシクロアルキル基、置換又は無置換フェニル基、置換又は無置換アラルキル基、アルコキシ基、ヒドロキシ基、及び、ハロゲン原子から選ばれるものである。ｎは１〜４の整数を示す。）
（３） 前記一般式［１］で示される化合物が、前記構造式中のＸが水素及びメチル基から選ばれるものであり、一般式［１］中のｎ＝１〜４である上記（１）に記載の一液型エポキシ樹脂組成物。
（４）前記一般式［１］で示される化合物が、Ｒがフェニル基及びｏ−トリル基から選ばれるものであり、ｍ＝１〜２である上記（１）に記載の一液型エポキシ樹脂組成物。
（５） 上記一般式［１］で表される化合物が、下記式［２］で表される化合物である上記（１）に記載の一液型エポキシ樹脂組成物。

(In the structural formula, X is hydrogen, an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted aralkyl group, an alkoxy group, a hydroxy group, And n is an integer of 1 to 4.
(3) In the compound represented by the general formula [1], X in the structural formula is selected from hydrogen and a methyl group, and n = 1 to 4 in the general formula [1] (1 ) One-pack type epoxy resin composition.
(4) The one-component epoxy resin according to (1), wherein R is selected from a phenyl group and an o-tolyl group, and m = 1 to 2 in the compound represented by the general formula [1]. Composition.
(5) The one-pack type epoxy resin composition according to the above (1), wherein the compound represented by the general formula [1] is a compound represented by the following formula [2].

  The present invention provides a one-pack type epoxy resin composition that is excellent in airtightness, in particular, adhesion to engineering plastics and metal terminals even in high temperatures in a reflow process, and excellent in storage stability in a small relay.

  Examples of the epoxy resin (A) used in the present invention include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, novolac type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, A glycidylamine type epoxy resin, a dicyclopentadiene type epoxy resin, a saturated aliphatic or unsaturated aliphatic epoxy resin, an alicyclic epoxy resin, and the like may be mentioned, and these may be used alone or in combination.

  The guanidine compound (B) used in the present invention is not particularly limited as long as it has a guanidine structure in the molecule, but a structure represented by the following structural formula [1] is particularly preferable. A guanidine compound (B) represented by the following structural formula [1] reacts an amine compound represented by the following general formula [3] with dicyandiamide represented by the following general formula [4] in the presence of an acidic catalyst. Is obtained.

In the general formula [3], R represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, or the general formula [2]. m shows the integer of 1-2.

The amount of the guanidine compound (B) used is usually 1 to 7 parts by weight of the guanidine compound (B) out of 100 parts by weight of the total epoxy resin. If it is less than 1 part by weight, the adhesion strength with the metal is reduced, and if it is more than 7 parts by weight, the adhesion strength with the LCP after the reflow treatment is reduced.

As the latent curing agent (C) used in the present invention, a commercially available adduct compound is excellent. For example, typical curing agents such as Ajinomoto Fine Techno Co., Ltd. Amicure PN-23, MY-24 and Fuji Chemical Industry Co., Ltd. Fuji Cure FXE-1000. Further, it may be a master batch type curing agent for a one-component epoxy resin disclosed in JP-A-1-70523 or a latent curing agent disclosed in JP-A-6-73156. Used as appropriate. The amount of the curing agent used here is 5 to 50 parts by weight, preferably 10 to 30 parts by weight of the latent curing agent (C) with respect to 100 parts by weight of the total epoxy resin (A). When it is less than 5 parts by weight, curing is insufficient. On the other hand, when the amount exceeds 50 parts by weight, the storage stability is remarkably deteriorated.

  In addition to the above components, the one-pack type epoxy resin composition of the present invention may contain components added to a normal epoxy resin composition as necessary. For example, inorganic fillers such as calcium carbonate, barium sulfate, aluminum hydroxide, magnesium hydroxide, reactive diluents, non-reactive diluents, plasticizers, dyes, pigments, coupling agents, wetting agents, leveling agents, thixo A tropicity imparting agent, an antifoaming agent, a storage stabilizer and the like can be used.

  In the production method of the one-pack type epoxy resin composition of the present invention, general stirring and mixing equipment and processing conditions similar to those of the ordinary production method of the epoxy resin composition are applied. The equipment to be used is not particularly limited, and examples thereof include a mixing roll, a dissolver, a planetary mixer, a kneader, and an extruder. As processing conditions, it may be heated in order to dissolve and / or lower the viscosity of the epoxy resin or the like to improve the stirring and mixing efficiency. Further, cooling may be performed in order to remove frictional heat generation, reaction heat generation, and the like. The time for stirring and mixing may be determined if necessary, and is not particularly limited.

Next, the one-pack type epoxy resin composition of the present invention will be described in more detail with reference to examples.
(Example 1) Bisphenol A type epoxy resin (epoxy equivalent: 190 [g / eq]) 100 parts by weight, o-tolylbiguanide 4 parts by weight, epoxy resin amine adduct curing agent 20 parts by weight, storage stabilizer thixotropic agent 1 Part by weight, 30 parts by weight of calcium carbonate, and 0.5 parts by weight of the colorant were mixed in the proportions shown in Table 1, and then kneaded using a mixing roll to prepare a one-pack type epoxy resin composition.

(Example 2) A bisphenol A type epoxy resin (epoxy equivalent: 190 [g / eq]) was reduced to 50 parts by weight, and a bisphenol F type epoxy resin (epoxy equivalent: 170 [g / eq]) was added to 50 parts by weight. A one-pack type epoxy resin composition was prepared in the same manner as in Example 1 except that.

(Example 3) A one-component epoxy resin composition was prepared in the same manner as in Example 1 except that the amount was reduced to 2 parts by weight of o-tolylbiguanide.

(Example 4) A one-pack type epoxy resin composition was prepared in the same manner as in Example 2 except that the amount was increased to 6 parts by weight of o-tolylbiguanide.

(Comparative Example 1) 100 parts by weight of a bisphenol A type epoxy resin (epoxy equivalent: 190 [g / eq]), 6 parts by weight of an epoxy resin amine adduct curing agent as a curing agent, 12 parts by weight of dicyandiamide, 1 part by weight of a thixotropic agent, After mixing 30 parts by weight of calcium carbonate and 0.5 parts by weight of the colorant, the mixture was kneaded using a mixing roll to prepare a one-pack type resin composition.

Comparative Example 2 A one-component resin composition was prepared in the same manner as in Example 4 except that o-tolylbiguanide was changed to dicyandiamide.

(1) Phosphor bronze Tensile shear strength One-pack type (epoxy) resin compositions obtained in Examples and Comparative Examples were bonded to phosphor bronze test pieces, cured at 120 ° C. for 60 minutes, and test pieces for evaluation. Was made. The tensile shear strength at 25 ° C. and 260 ° C. was measured according to JIS K 6850.

(2) LCP Similar to the tensile shear strength, the LCP test piece was bonded with the one-pack type (epoxy) resin composition obtained in Examples and Comparative Examples, and cured at 120 ° C. for 60 minutes, and the test piece for evaluation was used. Was made. The tensile shear strength at 25 ° C. and 260 ° C. of the obtained test piece was measured according to JIS K 6850.

(3) Relay airtightness Infrared reflow processing (IRS method) was performed using a relay. The treatment conditions were preheating at 150 ° C. for 90 to 120 seconds, heating at 200 ° C. within 30 seconds and the maximum temperature being 260 ° C. or less. Then, it was immersed in florinate and the airtightness was confirmed visually. Airtightness was determined according to the following criteria.
When bubbles are not generated during immersion: ○, when bubbles are generated: ×

(4) Storage stability The said resin composition was preserve | saved at 40 degreeC, and the number of days until gelatinizing was measured.

Table 1 shows the blending amount of each raw material. All units are parts by weight. The measurement results are shown in Table 2.

(Raw materials used)
Epoxy resin A: bisphenol A type epoxy resin (epoxy equivalent: 190) manufactured by Japan Epoxy Resin Co., Ltd. Epicoat 828
Epoxy resin B: Bisphenol F type epoxy resin (epoxy equivalent: 170) Epicoat 807 manufactured by Japan Epoxy Resin Co., Ltd.
Adduct hardener: Epoxy resin amine adduct hardener Ajinomoto Fine Techno Co., Ltd. Amicure PN-23
Dicyandiamide: EpiCure DICY15 manufactured by Japan Epoxy Resin Co., Ltd.
Storage stabilizer: Triisopropyl borate, manufactured by Kanto Chemical Co., Inc. Reagent thixotropic agent: Nippon Aerosil AEROSIL200
Calcium carbonate: NS # 100 manufactured by Nitto Flour Chemical Co., Ltd.
Colorant: Mitsubishi Chemical Carbon Black MA-600

  As is apparent from the results in Table 2, Examples 1 to 4 using the one-part resin composition of the present invention containing the epoxy resin (A), the guanidine compound (B), and the latent curing agent (C) are as follows: The phosphor bronze tensile shear strength was comparable to Comparative Examples 1 and 2 not containing these components, but the LCP tensile shear strength at 260 ° C. was markedly superior. Furthermore, the airtightness and the storage stability of the relay multiple times were also excellent.

Claims (5)

An epoxy resin composition for insulating and sealing a small relay or a small electronic / electrical component having an engineering plastic as a component, and comprising an epoxy resin (A), a guanidine compound (B), a latent curing agent ( A one-component epoxy resin composition comprising C) as an essential component and containing 1 to 7 parts by weight of the guanidine compound (B) with respect to 100 parts by weight of the epoxy resin (A). The one-component epoxy resin composition according to claim 1, wherein the guanidine compound (B) is represented by the following structural formula.

In the general formula [1], R represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, or the following structural formula. m shows the integer of 1-2.

(In the structural formula, X is hydrogen, an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted aralkyl group, an alkoxy group, a hydroxy group, And n is an integer of 1 to 4. The compound represented by the general formula [1] is such that X in the structural formula is selected from hydrogen and a methyl group, and n = 1 to 4 in the general formula [1]. One-pack type epoxy resin composition. The one-component epoxy resin composition according to claim 1, wherein the compound represented by the general formula [1] is one in which R is selected from a phenyl group and an o-tolyl group, and m = 1 to 2. The one-pack type epoxy resin composition according to claim 1, wherein the compound represented by the general formula [1] is a compound represented by the following formula [2].