JPH10149721A - Conductive paste and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive paste with little resistance alteration due to a solder heat resistance test, boiling test, etc., and having high reliability and provide a method for producing the paste. SOLUTION: This conductive paste comprises resin having a thermosetting property, compatibility with an organic solvent, and 25,000-50,000 weight average molecular weight, an organic solvent, and a conductive powder. The method for producing the paste includes steps of mixing the resin having thermosetting property and compatibility with an organic solvent and the organic solvent and then heating the resultant mixture to promote thermosetting reaction and to obtain a resin composition with 25,000-50,000 weight average molecular weight and adding and mixing a conductive powder to and with the resultant resin composition.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は導電ペースト及びそ
の製造法に関する。The present invention relates to a conductive paste and a method for producing the same.

【０００２】[0002]

【従来の技術】従来、プリント配線板、電子部品等の配
線導体を形成する方法として、電子材料、１９９４年１
０月号の４２〜４６頁に記載されているように金、銀、
銅、カーボンなどの導電性粉末を用い、それに熱硬化性
樹脂、溶剤を加えてペースト状に混合した導電ペースト
を塗布又は印刷する方法が一般的に知られている。特に
高導電性が要求される分野では、金粉、銀粉又はこれら
の合金粉が一般的に用いられている。2. Description of the Related Art Conventionally, as a method of forming a wiring conductor of a printed wiring board, an electronic component, or the like, an electronic material, January 1994
As described on page 42-46 of the October issue, gold, silver,
It is generally known to use a conductive powder such as copper or carbon, and apply or print a conductive paste obtained by adding a thermosetting resin and a solvent thereto and mixing the paste into a paste. Particularly in the field where high conductivity is required, gold powder, silver powder or alloy powder thereof is generally used.

【０００３】さらに従来の導電ペーストは一般的に、特
公平３−３９５３６号公報、特開平１−２５３１１１号
公報等に見られるように、構造、平均分子量等を規定し
たエポキシ樹脂、フェノール樹脂等の熱硬化性樹脂、導
電粉、有機溶剤、添加剤等を混練して製造している。Further, conventional conductive pastes are generally made of epoxy resin, phenol resin or the like having a specified structure, average molecular weight, etc., as disclosed in Japanese Patent Publication No. 3-39536 and Japanese Patent Application Laid-Open No. 1-253111. It is manufactured by kneading thermosetting resin, conductive powder, organic solvent, additives and the like.

【０００４】しかしながら、構造、平均分子量等を規定
したエポキシ樹脂、フェノール樹脂等の熱硬化性樹脂を
用いた導電ペーストは、印刷して配線導体形成後の１５
０〜１６０℃の温度で３０〜４５分間程度の硬化時間で
は、硬化促進剤を使用しても熱硬化性樹脂の未反応基が
残存してしまい、そのため、配線板のはんだ耐熱試験、
煮沸試験等により抵抗変化率が大きいという欠点が生じ
る。この対策として、酸性又はアルカリ性の強い硬化促
進剤の使用及びその量の増量と硬化温度を高くして硬化
時間を長くするという方法があるが、この方法でも十分
な効果が得られるものではなかった。[0004] However, a conductive paste using a thermosetting resin such as an epoxy resin or a phenol resin having a specified structure, average molecular weight, etc., is printed and printed after forming a wiring conductor.
At a curing time of about 30 to 45 minutes at a temperature of 0 to 160 ° C., even if a curing accelerator is used, unreacted groups of the thermosetting resin remain.
There is a disadvantage that the rate of change in resistance is large by a boiling test or the like. As a countermeasure, there is a method of using a hardening accelerator having strong acidity or alkalinity and increasing the amount thereof and increasing the curing temperature to lengthen the curing time. However, this method has not been able to obtain a sufficient effect. .

【０００５】[0005]

【発明が解決しようとする課題】請求項１記載の発明
は、はんだ耐熱試験、煮沸試験等による抵抗変化率が小
さく、信頼性に優れた導電ペーストを提供するものであ
る。請求項２及び３記載の発明は、はんだ耐熱試験、煮
沸試験等による抵抗変化率が小さく、信頼性に優れた導
電ペーストの製造法を提供するものである。An object of the present invention is to provide a conductive paste which has a small rate of change in resistance in a solder heat resistance test, a boiling test and the like, and is excellent in reliability. The inventions according to claims 2 and 3 provide a method for producing a conductive paste having a small rate of change in resistance in a solder heat test, a boiling test, and the like, and having excellent reliability.

【０００６】[0006]

【課題を解決するための手段】本発明は、熱硬化性を有
し、かつ有機溶剤と相溶性を有し、しかも重量平均分子
量が２５，０００〜５０，０００である樹脂、有機溶剤
及び導電粉を含有してなる導電ペーストに関する。又、
本発明は、熱硬化性を有し、かつ有機溶剤と相溶性を有
する樹脂と有機溶剤とを混合した後、加温して熱硬化反
応を促進させて、樹脂の重量平均分子量を２５，０００
〜５０，０００とした樹脂組成物に、導電粉を添加して
混合することを特徴とする導電ペーストの製造法に関す
る。さらに、本発明は、この導電ペーストの製造法にお
いて、樹脂が、エポキシ当量が１７５〜１，５００のエ
ポキシ樹脂又は重量平均分子量が３００〜８，０００の
フェノール樹脂である導電ペーストの製造法に関する。DISCLOSURE OF THE INVENTION The present invention relates to a resin, an organic solvent and a resin having a thermosetting property, being compatible with an organic solvent, and having a weight average molecular weight of 25,000 to 50,000. The present invention relates to a conductive paste containing powder. or,
In the present invention, a resin having a thermosetting property and being compatible with an organic solvent is mixed with an organic solvent, and then heated to promote a thermosetting reaction, so that the weight average molecular weight of the resin is 25,000.
The present invention relates to a method for producing a conductive paste, which comprises adding a conductive powder to a resin composition having a molecular weight of up to 50,000 and mixing. Furthermore, the present invention relates to a method for producing the conductive paste, wherein the resin is an epoxy resin having an epoxy equivalent of 175 to 1,500 or a phenol resin having a weight average molecular weight of 300 to 8,000.

【０００７】[0007]

【発明の実施の形態】本発明に用いられる樹脂組成物
は、熱硬化性を有し、かつ有機溶剤と相溶性を有する樹
脂と有機溶剤とを含む混合物を加温して熱硬化反応を促
進させた重量平均分子量が２５，０００〜５０，００
０、より好ましくは３０，０００〜５０，０００の範囲
の樹脂組成物を用いることが必要とされ、重量平均分子
量が２５，０００未満の樹脂組成物を用いると、はんだ
耐熱試験、煮沸試験等の抵抗変化率が大きくなり、また
重量平均分子量が５０，０００を超える樹脂組成物を用
いると、樹脂組成物がゲル化するという欠点が生じる。DESCRIPTION OF THE PREFERRED EMBODIMENTS The resin composition used in the present invention has a thermosetting property and accelerates a thermosetting reaction by heating a mixture containing a resin having compatibility with an organic solvent and an organic solvent. Weight average molecular weight of 25,000 to 50,000
It is necessary to use a resin composition having a weight average molecular weight of less than 25,000, and more preferably a resin composition having a weight average molecular weight of less than 25,000, such as a solder heat resistance test and a boiling test. The use of a resin composition having a high rate of change in resistance and having a weight average molecular weight of more than 50,000 causes a disadvantage that the resin composition is gelled.

【０００８】上記の樹脂としては、導電ペースト硬化後
の導電性及び基材との密着性の点からエポキシ樹脂及び
／又はフェノール樹脂を用いることが好ましく、特にビ
スフェノールＡ型エポキシ樹脂及び／又はレゾール型フ
ェノール樹脂を用いることが好ましい。As the above-mentioned resin, it is preferable to use an epoxy resin and / or a phenol resin from the viewpoint of the conductivity after curing of the conductive paste and the adhesion to the substrate, and particularly, a bisphenol A type epoxy resin and / or a resol type resin. It is preferable to use a phenol resin.

【０００９】なお、上記のエポキシ樹脂は、エポキシ当
量が１７５〜１，５００の範囲が好ましく、１８０〜
１，３００の範囲であることがより好ましい。エポキシ
当量が１７５未満であると、導電ペースト硬化物の弾性
率が高くなり、曲げ試験での抵抗変化率が大きくなる傾
向があり、１，５００を超えると、エポキシ基の数が少
なく、樹脂組成物に未反応基が残存してしまい、はんだ
耐熱試験、煮沸試験等の抵抗変化率が大きくなる傾向が
ある。The above epoxy resin preferably has an epoxy equivalent in the range of 175 to 1,500,
More preferably, it is in the range of 1,300. If the epoxy equivalent is less than 175, the elastic modulus of the cured conductive paste tends to increase, and the resistance change rate in the bending test tends to increase. If it exceeds 1,500, the number of epoxy groups decreases and the resin composition decreases. Unreacted groups remain in the product, and the rate of change in resistance in solder heat resistance tests, boiling tests, and the like tends to increase.

【００１０】一方、フェノール樹脂は、重量平均分子量
が３００〜８，０００の範囲が好ましく、４００〜５，
０００の範囲であることがより好ましい。重量平均分子
量が３００未満であると、合成が困難となる傾向があ
り、８，０００を超えると、フェノール樹脂の反応基の
数が少なくなる傾向がある。本発明において重量平均分
子量は、ゲルパーミエーションクロマトグラフィー法に
より標準ポリスチレンの検量線を用いて求めた値であ
る。On the other hand, the phenol resin preferably has a weight average molecular weight in the range of 300 to 8,000,
More preferably, it is in the range of 000. If the weight average molecular weight is less than 300, synthesis tends to be difficult, and if it exceeds 8,000, the number of reactive groups in the phenol resin tends to decrease. In the present invention, the weight average molecular weight is a value determined by a gel permeation chromatography method using a standard polystyrene calibration curve.

【００１１】熱硬化性を有し、かつ有機溶剤と相溶性を
有する樹脂と有機溶剤とを含む混合物を加温する方法に
ついては特に制限はないが、樹脂と有機溶剤との混合物
を撹拌又は該混合物を入れた容器を回転させながら加温
することが好ましい。例えば、該混合物をフラスコに入
れ、ロータリーエバポレーター及びオイルバスを用いて
加温することができる。There is no particular limitation on the method of heating a mixture containing a resin having thermosetting properties and being compatible with an organic solvent and an organic solvent, but the mixture of the resin and the organic solvent is stirred or mixed. It is preferable to heat while rotating the container containing the mixture. For example, the mixture can be placed in a flask and heated using a rotary evaporator and an oil bath.

【００１２】樹脂と有機溶剤の配合割合は、樹脂１００
重量部に対して有機溶剤が８０〜１２０重量部の範囲が
好ましく、９０〜１１０重量部の範囲であることがより
好ましい。なお、有機溶剤は、エチルカルビトール、ブ
チルカルビトール、エチルカルビトールアセテート、ブ
チルカルビトールアセテート、ブチルセロソルブ、ブチ
ルセロソルブアセテート、エチルセロソルブ、エチルセ
ロソルブアセテート等を用いることができる。The mixing ratio of the resin and the organic solvent is 100
The amount of the organic solvent is preferably in the range of 80 to 120 parts by weight, more preferably in the range of 90 to 110 parts by weight with respect to parts by weight. As the organic solvent, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, butyl carbitol acetate, butyl cellosolve, butyl cellosolve acetate, ethyl cellosolve, ethyl cellosolve acetate, or the like can be used.

【００１３】本発明の導電ペーストに用いる導電粉は、
良好な導電性を有する金属粉である銀粉、銅粉、銀めっ
き銅粉、金粉、ニッケル粉又はこれらの混合粉を用いる
ことができる。導電粉としては、アスペクト比が２〜２
０及び長径の平均粒径が３〜３０μｍの導電粉を用いる
ことが好ましく、アスペクト比が５〜１５及び長径の平
均粒径が５〜２０μｍの導電粉を用いることができる。
なお上記でいう平均粒径は、レーザー散乱型粒度分布測
定装置により測定することができる。このような装置と
しては、例えば、マスターサイザー（マルバン・インス
ルメンツ社製）がある。The conductive powder used in the conductive paste of the present invention is:
Silver powder, copper powder, silver-plated copper powder, gold powder, nickel powder, or a mixed powder thereof, which is a metal powder having good conductivity, can be used. As the conductive powder, the aspect ratio is 2-2.
It is preferable to use conductive powder having an average particle diameter of 0 and a major axis of 3 to 30 μm, and an electrically conductive powder having an aspect ratio of 5 to 15 and an average particle diameter of a major axis of 5 to 20 μm can be used.
The average particle size mentioned above can be measured by a laser scattering type particle size distribution measuring device. As such an apparatus, for example, there is a master sizer (manufactured by Malvan Instruments).

【００１４】本発明におけるアスペクト比とは、導電粉
及び銀粉の粒子の長径と短径の比率（長径／短径）をい
う。本発明においては、粘度の低い硬化性樹脂中に導電
粉の粒子をよく混合し、静置して粒子を沈降させるとと
もにそのまま樹脂を硬化させ、得られた硬化物を垂直方
向に切断し、その切断面に現れる粒子の形状を電子顕微
鏡で拡大して観察し、少なくとも１００の粒子について
一つ一つの粒子の長径／短径を求め、それらの平均値を
もってアスペクト比とする。ここで、短径とは、前記切
断面に現れる粒子について、その粒子の外側に接する二
つの平行線の組合せを粒子を挾むように選択し、それら
の組合せのうち最短間隔になる二つの平行線の距離であ
る。一方、長径とは、前記短径を決する平行線に直角方
向の二つの平行線であって、粒子の外側に接する二つの
平行線の組合せのうち、最長間隔になる二つの平行線の
距離である。これらの四つの線で形成される長方形は、
粒子がちょうどその中に納まる大きさとなる。なお、本
発明において行った具体的方法については後述する。The aspect ratio in the present invention refers to the ratio of the major axis to the minor axis (major axis / minor axis) of the particles of the conductive powder and silver powder. In the present invention, the particles of the conductive powder are mixed well in the curable resin having a low viscosity, and the resin is cured while allowing the particles to settle by standing, and the obtained cured product is cut in the vertical direction. The shape of the particles appearing on the cut surface is observed under magnification with an electron microscope, and the major axis / minor axis of each particle is obtained for at least 100 particles, and the average value thereof is defined as the aspect ratio. Here, the minor axis is defined as a combination of two parallel lines contacting the outside of the particle with respect to the particle appearing on the cut surface so as to sandwich the particle. Distance. On the other hand, the major axis is the two parallel lines perpendicular to the parallel line that determines the minor axis, and is the distance between the two parallel lines that are the longest among the combinations of the two parallel lines that contact the outside of the particle. is there. The rectangle formed by these four lines is
The particles are sized just to fit inside. The specific method used in the present invention will be described later.

【００１５】本発明になる導電ペーストは、上記の材料
以外に、必要に応じ飽和ポリエステル樹脂、アクリル樹
脂、フェノキシ樹脂、ビニル樹脂、ポリブタジエン樹脂
等の熱可塑性樹脂、２エチル４メチルイミダゾールなど
の硬化剤及びベンゾチアゾール、ベンズイミダゾール等
の腐食抑制剤、微小黒鉛粉末等を添加して均一に混合し
て得られる。In addition to the above-mentioned materials, the conductive paste according to the present invention may be, if necessary, a thermoplastic resin such as a saturated polyester resin, an acrylic resin, a phenoxy resin, a vinyl resin or a polybutadiene resin, or a curing agent such as 2-ethyl-4-methylimidazole. And a corrosion inhibitor such as benzothiazole or benzimidazole, fine graphite powder and the like are added and uniformly mixed.

【００１６】必要に応じ添加される飽和ポリエステル樹
脂、アクリル樹脂、フェノキシ樹脂、ビニル樹脂、ポリ
ブタジエン樹脂等の熱可塑性樹脂は、樹脂組成物中に１
５重量％以下含有することが好ましい。また、硬化剤の
含有量は、作業性の点で樹脂組成物１００重量部に対し
て０．５〜１０重量部の範囲であることが好ましく、１
〜８重量部の範囲であることがより好ましい。さらに、
腐食抑制剤の含有量は、樹脂組成物１００重量部に対し
て０．１〜３重量部の範囲であることが好ましく、微小
黒鉛粉末の含有量は、導電ペーストに対して１〜１０重
量％の範囲であることが好ましい。A thermoplastic resin such as a saturated polyester resin, an acrylic resin, a phenoxy resin, a vinyl resin, or a polybutadiene resin, which is added as required, is contained in the resin composition in an amount of 1%.
It is preferable to contain 5% by weight or less. In addition, the content of the curing agent is preferably in the range of 0.5 to 10 parts by weight with respect to 100 parts by weight of the resin composition from the viewpoint of workability.
More preferably, the amount is in the range of 8 to 8 parts by weight. further,
The content of the corrosion inhibitor is preferably in the range of 0.1 to 3 parts by weight based on 100 parts by weight of the resin composition, and the content of the fine graphite powder is 1 to 10% by weight based on the conductive paste. Is preferably within the range.

【００１７】[0017]

【実施例】以下本発明の実施例を説明する。 実施例１ ビスフェノールＡ型エポキシ樹脂（三井石油化学工業
(株)製、商品名Ｒ１３０、エポキシ当量１９０〜２１
０）１０重量部、レゾール型フェノール樹脂（群栄化学
工業(株)製、商品名レヂトップＰＬ−２２１１、重量平
均分子量２，０００）の溶剤を除去して固形化したもの
８０重量部、エチルカルビトール４５重量部及びブチル
セロソルブ４５重量部を加えて均一に混合して樹脂混合
物とした。この樹脂混合物を１リットルナス型フラスコ
に入れ、ロータリーエバポレーターとオイルバスを用
い、回転速度が１００rpm、オイルバスの温度１３０℃
で１５０分間の条件で回転させながら加温して熱硬化反
応を促進させ、重量平均分子量が３７，５００の樹脂組
成物を得た。Embodiments of the present invention will be described below. Example 1 Bisphenol A type epoxy resin (Mitsui Petrochemical Industries
Co., Ltd., trade name R130, epoxy equivalent 190 to 21
0) 10 parts by weight, solidified after removing the solvent of resol type phenol resin (trade name: Retop PL-2211, manufactured by Gunei Chemical Industry Co., Ltd., weight average molecular weight: 2,000) 80 parts by weight, ethyl carb 45 parts by weight of tall and 45 parts by weight of butyl cellosolve were added and uniformly mixed to obtain a resin mixture. This resin mixture was placed in a 1-liter eggplant-shaped flask, and the rotation speed was 100 rpm and the temperature of the oil bath was 130 ° C. using a rotary evaporator and an oil bath.
The solution was heated while rotating under the conditions of 150 minutes to accelerate the thermosetting reaction, thereby obtaining a resin composition having a weight average molecular weight of 37,500.

【００１８】上記で得た樹脂組成物１８０重量部、飽和
ポリエステル樹脂（日立化成工業(株)製、商品名ＰＳ−
９２０１−１０）１０重量部、長径の平均粒径が１０．
２μｍ及びアスペクト比が８．８の銀粉（徳力化学研究
所製、商品名ＴＣＧ−１）５６０重量部及び２エチル４
メチルイミダゾール５重量部を加えて撹拌らいかい機及
び三本ロールで均一に混合分散して導電ペーストを得
た。180 parts by weight of the resin composition obtained above, a saturated polyester resin (trade name: PS-, manufactured by Hitachi Chemical Co., Ltd.)
9201-10) 10 parts by weight, average particle diameter of major axis is 10.
560 parts by weight of 2 μm silver powder having an aspect ratio of 8.8 (trade name: TCG-1 manufactured by Tokurika Chemical Laboratory) and 2 ethyl 4
5 parts by weight of methylimidazole was added, and the mixture was uniformly mixed and dispersed with a stirrer and a three-roll mill to obtain a conductive paste.

【００１９】次に上記で得た導電ペーストを用いて厚さ
が１．６mmの紙フェノール銅張り積層板（日立化成工業
(株)製、商品名ＭＣＬ−４３７Ｆ）の銅箔をエッチング
して除去した面に、図１に示すテストパターン１を印刷
したものを大気中で８０℃で１時間さらに１５０℃で４
０分の条件で加熱処理して配線板を得た。なお図１にお
いて２は紙フェノール銅張り積層板である。得られた配
線板の比抵抗を測定したところ３４２．２μΩ・cmであ
った。Next, a 1.6 mm-thick paper-phenol copper-clad laminate (Hitachi Chemical Industries, Ltd.) was prepared using the conductive paste obtained above.
The test pattern 1 shown in FIG. 1 was printed on the surface of the copper foil (trade name: MCL-437F, manufactured by Co., Ltd.) which was removed by etching.
Heat treatment was performed under the condition of 0 minutes to obtain a wiring board. In FIG. 1, reference numeral 2 denotes a paper phenol copper-clad laminate. When the specific resistance of the obtained wiring board was measured, it was 342.2 μΩ · cm.

【００２０】一方、図２に示すように上記と同様の紙フ
ェノール銅張り積層板２に直径が０．８mmのスルーホー
ル３を形成し、かつ銅箔の一部をエッチングして除去し
て回路４を形成した後、上記で得た導電ペーストを該ス
ルーホール３に充てんしたものを上記と同様の条件で加
熱処理して配線板を得た。On the other hand, as shown in FIG. 2, a through-hole 3 having a diameter of 0.8 mm is formed in a paper phenol copper-clad laminate 2 similar to the above, and a part of the copper foil is removed by etching. After the formation of No. 4, the conductive paste obtained above was filled in the through holes 3 and heat-treated under the same conditions as above to obtain a wiring board.

【００２１】得られた配線板の１穴当たりの抵抗値は、
２１．６ｍΩ／穴であった。また該配線板のはんだ耐熱
試験、煮沸試験及びホットオイル試験を実施した結果、
はんだ耐熱試験の抵抗変化率は＋８．２％、煮沸試験は
＋４．３％及びホットオイル試験は＋２１．９％であっ
た。なお、はんだ耐熱試験は２６０℃ ５秒間を５サイ
クル、煮沸試験は１００℃沸騰水浸漬２時間〜室温放置
２２時間を１サイクルとし、これを５サイクル及びホッ
トオイル試験は２６０℃オイル槽に１０秒間浸漬〜２０
℃水槽に１０秒間浸漬を１サイクルとし、これを１００
サイクル行った。The resistance value per hole of the obtained wiring board is
It was 21.6 mΩ / hole. In addition, as a result of conducting a soldering heat test, a boiling test and a hot oil test of the wiring board,
The resistance change rate in the soldering heat test was + 8.2%, the boiling test was + 4.3%, and the hot oil test was + 21.9%. The solder heat resistance test was performed at 260 ° C. for 5 seconds for 5 cycles, and the boiling test was performed at 100 ° C. for 2 hours to room temperature at room temperature for 22 hours as one cycle. Immersion ~ 20
Immersion in a water bath for 10 seconds as one cycle.
Cycled.

【００２２】なお、本実施例におけるアスペクト比の具
体的測定法を以下に示す。低粘度のエポキシ樹脂（ビュ
ーラー社製）の主剤（No.２０−８１３０）８ｇと硬化
剤（No.２０−８１３２）２ｇを混合し、ここへ銀粉２
ｇを混合して良く分散させ、そのまま３０℃で真空脱泡
した後、６〜８時間３０℃で静置して粒子を沈降させ硬
化させた。その後、得られた硬化物を垂直方向に切断
し、切断面を電子顕微鏡で２０００倍に拡大して切断面
に現われた１００個の粒子について長径／短径を求め、
それらの平均値をもって、アスペクト比とした。The specific method of measuring the aspect ratio in this embodiment will be described below. 8 g of a base material (No. 20-8130) of a low-viscosity epoxy resin (manufactured by Buehler) and 2 g of a curing agent (No. 20-8132) were mixed, and silver powder 2 was added.
g were mixed and dispersed well, followed by vacuum degassing at 30 ° C. as it was, and then allowed to stand at 30 ° C. for 6 to 8 hours to precipitate and harden the particles. Thereafter, the obtained cured product was cut in the vertical direction, the cut surface was magnified 2000 times with an electron microscope, and the long diameter / short diameter was determined for 100 particles that appeared on the cut surface,
The average value was used as the aspect ratio.

【００２３】実施例２ ビスフェノールＡ型エポキシ樹脂（三井石油化学工業
(株)製、商品名Ｒ３０２、エポキシ当量５７５〜７２
５）１０重量部、レゾール型フェノール樹脂（群栄化学
工業(株)製、商品名レヂトップＰＬ−２２１２、重量平
均分子量４，０００）の溶剤を除去し固形化したもの８
０重量部、エチルカルビトール４５重量部及びブチルセ
ロソルブ４５重量部を加えて均一に混合して樹脂混合物
とし、以下実施例１と同様の工程を経て重量平均分子量
が３２，０００の樹脂組成物を得た。Example 2 Bisphenol A type epoxy resin (Mitsui Petrochemical Industries, Ltd.)
Co., Ltd., trade name R302, epoxy equivalent 575-72
5) A solid obtained by removing 10 parts by weight of a solvent of a resol type phenol resin (trade name: Retop PL-2212, manufactured by Gun Ei Chemical Co., Ltd., weight average molecular weight: 4,000) 8
0 parts by weight, 45 parts by weight of ethyl carbitol, and 45 parts by weight of butyl cellosolve were added and uniformly mixed to obtain a resin mixture, and a resin composition having a weight average molecular weight of 32,000 was obtained through the same steps as in Example 1 below. Was.

【００２４】上記で得た樹脂組成物１８０重量部に、実
施例１で用いた飽和ポリエステル樹脂１０重量部、銀粉
５６０重量部及び２エチル４メチルイミダゾール５重量
部を加えて撹拌らいかい機及び三本ロールで均一に混合
分散して導電ペーストを得た。To 180 parts by weight of the resin composition obtained above, 10 parts by weight of the saturated polyester resin used in Example 1, 560 parts by weight of silver powder, and 5 parts by weight of 2-ethyl-4-methylimidazole were added. The conductive paste was obtained by uniformly mixing and dispersing with this roll.

【００２５】次に実施例１と同様の工程を経て実施例１
と同様の配線板を作製してその特性を評価した。その結
果、比抵抗は５１．２μΩ・cmであり、スルーホール１
穴当たりの抵抗値は１８．７ｍΩ／穴であった。または
んだ耐熱試験の抵抗変化率は−４．８％、煮沸試験は＋
５．４％及びホットオイル試験は＋２８．０％であっ
た。Next, through the same steps as in the first embodiment, the first embodiment
A wiring board similar to that described above was produced and its characteristics were evaluated. As a result, the specific resistance was 51.2 μΩ · cm,
The resistance per hole was 18.7 mΩ / hole. The resistance change rate in the soldering heat test was -4.8%, and the boiling test was +
5.4% and the hot oil test was + 28.0%.

【００２６】比較例１ 実施例１で得た樹脂混合物（重量平均分子量３，００
０）を加温せずに、この樹脂混合物１８０重量部に、実
施例１で用いた飽和ポリエステル樹脂、銀粉及び２エチ
ル４メチルイミダゾールを実施例１と同量加えて、撹拌
らいかい機及び三本ロールで均一に混合分散して導電ペ
ーストを得た。Comparative Example 1 The resin mixture obtained in Example 1 (weight average molecular weight: 3,000
0) without heating, to 180 parts by weight of the resin mixture, the same amounts of the saturated polyester resin, silver powder and 2-ethyl-4-methylimidazole used in Example 1 as in Example 1 were added. The conductive paste was obtained by uniformly mixing and dispersing with this roll.

【００２７】次に実施例１と同様の工程を経て実施例１
と同様の配線板を作製してその特性を評価した。その結
果、比抵抗は５７．９μΩ・cmであり、スルーホール１
穴当たりの抵抗値は２３．８ｍΩ／穴であった。または
んだ耐熱試験の抵抗変化率は−２８．２％、煮沸試験は
−１９．３％及びホットオイル試験は＋９２．６％であ
った。Next, through the same steps as in the first embodiment, the first embodiment
A wiring board similar to that described above was produced and its characteristics were evaluated. As a result, the specific resistance was 57.9 μΩ · cm,
The resistance per hole was 23.8 mΩ / hole. The resistance change rate in the solder heat resistance test was -28.2%, the boiling test was -19.3%, and the hot oil test was + 92.6%.

【００２８】比較例２ 実施例１で得た樹脂混合物を実施例１と同様の方法で７
０分加温し、重量平均分子量が１５，０００の樹脂組成
物を得た。上記で得た樹脂組成物１８０重量部に、実施
例１で用いた飽和ポリエステル樹脂、銀粉及び２エチル
４メチルイミダゾールを実施例１と同量加えて、撹拌ら
いかい機及び三本ロールで均一に混合分散して導電ペー
ストを得た。Comparative Example 2 The resin mixture obtained in Example 1 was treated in the same manner as in Example 1
After heating for 0 minutes, a resin composition having a weight average molecular weight of 15,000 was obtained. To 180 parts by weight of the resin composition obtained above, the same amounts of the saturated polyester resin, silver powder and 2-ethyl-4-methylimidazole used in Example 1 as in Example 1 were added, and the mixture was uniformly mixed with a stirrer and a three-roll mill. The conductive paste was obtained by mixing and dispersing.

【００２９】次に実施例１と同様の工程を経て実施例１
と同様の配線板を作製してその特性を評価した。その結
果、比抵抗は５１．１μΩ・cmであり、スルーホール１
穴当たりの抵抗値は２２．０ｍΩ／穴であった。または
んだ耐熱試験の抵抗変化率は−２１．２％、煮沸試験は
−１５．３％及びホットオイル試験は＋８１．０％であ
った。Next, through the same steps as in the first embodiment, the first embodiment
A wiring board similar to that described above was produced and its characteristics were evaluated. As a result, the specific resistance was 51.1 μΩ · cm,
The resistance per hole was 22.0 mΩ / hole. The resistance change rate in the solder heat test was -21.2%, the boiling test was -15.3%, and the hot oil test was + 81.0%.

【００３０】[0030]

【発明の効果】請求項１記載の導電ペーストは、はんだ
耐熱試験、煮沸試験等による抵抗変化率が小さく、信頼
性に優れる。請求項２及び３記載の導電ペーストの製造
法は、はんだ耐熱試験、煮沸試験等による抵抗変化率が
小さく、信頼性に優れる導電ペーストが製造できる。The conductive paste according to the first aspect has a small rate of change in resistance in a solder heat resistance test, a boiling test and the like, and is excellent in reliability. According to the method for producing a conductive paste according to claims 2 and 3, a resistance change rate by a soldering heat test, a boiling test and the like is small, and a conductive paste excellent in reliability can be produced.

【図面の簡単な説明】[Brief description of the drawings]

【図１】紙フェノール銅張り積層板の銅箔をエッチング
して除去した面にテストパターンを印刷した状態を示す
平面図である。FIG. 1 is a plan view showing a state in which a test pattern is printed on a surface of a paper phenol copper-clad laminate obtained by etching and removing a copper foil.

【図２】紙フェノール銅張り積層板の銅箔の一部をエッ
チングして除去して回路を形成し、かつ導電ペーストを
スルーホールに充てんした状態を示す平面図である。FIG. 2 is a plan view showing a state in which a part of a copper foil of a paper phenol copper-clad laminate is etched away to form a circuit, and a conductive paste is filled in through holes.

【符号の説明】[Explanation of symbols]

１ テストパターン ２ 紙フェノール銅張り積層板 ３ スルーホール ４ 回路 1 Test pattern 2 Paper phenol copper clad laminate 3 Through hole 4 Circuit

Claims (3)

【特許請求の範囲】[Claims] 【請求項１】 熱硬化性を有し、かつ有機溶剤と相溶性
を有し、しかも重量平均分子量が２５，０００〜５０，
０００である樹脂、有機溶剤及び導電粉を含有してなる
導電ペースト。An organic solvent having a thermosetting property and a weight average molecular weight of 25,000 to 50,
000, a conductive paste containing a resin, an organic solvent and a conductive powder. 【請求項２】 熱硬化性を有し、かつ有機溶剤と相溶性
を有する樹脂と有機溶剤とを混合した後、加温して熱硬
化反応を促進させて、樹脂の重量平均分子量を２５，０
００〜５０，０００とした樹脂組成物に、導電粉を添加
して混合することを特徴とする導電ペーストの製造法。2. A resin having thermosetting properties and compatibility with an organic solvent and an organic solvent are mixed, and then heated to accelerate the thermosetting reaction, so that the resin has a weight average molecular weight of 25,25. 0
A method for producing a conductive paste, comprising adding and mixing a conductive powder to a resin composition having a resin composition of 00 to 50,000. 【請求項３】 樹脂が、エポキシ当量が１７５〜１，５
００のエポキシ樹脂又は重量平均分子量が３００〜８，
０００のフェノール樹脂である請求項２記載の導電ペー
ストの製造法。3. A resin having an epoxy equivalent of 175 to 1.5.
00 epoxy resin or a weight average molecular weight of 300 to 8,
3. The method for producing a conductive paste according to claim 2, wherein the phenolic resin is phenol resin.