JP3753470B2 - Anisotropic conductive adhesive - Google Patents
Anisotropic conductive adhesive Download PDFInfo
- Publication number
- JP3753470B2 JP3753470B2 JP14865096A JP14865096A JP3753470B2 JP 3753470 B2 JP3753470 B2 JP 3753470B2 JP 14865096 A JP14865096 A JP 14865096A JP 14865096 A JP14865096 A JP 14865096A JP 3753470 B2 JP3753470 B2 JP 3753470B2
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- JP
- Japan
- Prior art keywords
- paste
- anisotropic conductive
- particles
- conductive
- specific gravity
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
- H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
- H05K3/321—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by conductive adhesives
Landscapes
- Adhesives Or Adhesive Processes (AREA)
- Electric Connection Of Electric Components To Printed Circuits (AREA)
- Conductive Materials (AREA)
- Non-Insulated Conductors (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は、液晶表示素子の基板に形成した透明電極端子と駆動外部回路の配線電極端子等の接続等に使用されるペースト状の異方性導電材料の改良に関するものである。
【０００２】
【従来の技術】
従来、液晶表示素子における透明電極と駆動外部回路の配線パターンとを電気的に接続するに際して、高分子フィルム上に担持させたシート状の異方性導電膜が使用されている。その異方性導電膜は、絶縁性マトリックス中に半田やニッケルなどの金属粒子あるいは樹脂粒体表面をＮｉメッキした導電粒子を所定の濃度で分散させた接着性シートである。
【０００３】
この異方性導電膜の使用は、担体である高分子フィルムから剥離して2 つの配線パターンの間に配置し、配線パターンを支持したパネル基板及び駆動外部回路基板を加熱、加圧することにより、金属粒子または導電粒子が2 つの配線パターン間を導通させるとともに絶縁性マトリックスが溶け、該2 つの配線パターン間の異方性導通が固定された状態で接合がなされるのである。
【０００４】
この異方性導電膜における絶縁性マトリックスには多くの場合、接続の信頼性を得るためにエポキシ系熱硬化性樹脂が用いられており、詳しくは、エポキシ樹脂と、ポリアミド樹脂、アミン類、イミダゾール類、メラミン類、酸無水物類等の硬化剤が使用されている。
【０００５】
【発明が解決しようとする課題】
ところが、従来のシート状の異方性導電膜では、支持担体である高分子フィルムからの剥離不良や、シート状であることによって接合の形態が規制される等の問題点があった。そのため、ペースト等の液状異方性導電材料が提案されてきたが、液状である場合、使用前の保存時にバインダー樹脂と導電粒子の比重差から経時的に導電粒子が沈降凝集を起こしてしまうという別の問題点が生じていた。本発明の目的は、従来技術における問題点に鑑み、長期保存しても導電粒子の沈降凝集が生じにくい液状の異方性導電接着剤を提供することにある。
【０００６】
【課題を解決するための手段】
本発明は、前記目的を達成するために、導電粒子の平均粒径を規定したうえで、導電粒子の比重を一定以下に規定し、さらにペーストとしての常温における粘度を一定以上に規定することによって、長期間保存しても導電粒子の沈降凝集の防止を可能とすること見いだして、本発明を完成したものである。
【０００７】
すなわち、本発明は、異方性導電層を形成するためのペースト状の導電接着剤であって、平均粒子径が7.0 μｍ以下であるとともに比重が4.0 以下である導電粒子をエポキシ樹脂ペーストに分散させ、導電粒子分散後のエポキシ樹脂ペーストが有する25℃における粘度が 100ポイズ以上であることを特徴とする異方性導電接着剤である。
【０００８】
以下、本発明を詳細に説明する。
【０００９】
本発明に用いるエポキシ樹脂ペーストは、エポキシ基を有する樹脂成分とその硬化系成分とからなっている。エポキシ基を有する樹脂成分としては、1 分子中に2 個以上のエポキシ基を有する多価エポキシ樹脂であれば、一般に用いられているエポキシ樹脂が使用可能である。具体的なものとして、まず、フェノールノボラック、クレゾールノボラック等のノボラック樹脂、ビスフェノールＡ、ビスフェノールＦ、レゾルシン、ビスヒドロキシジフェニルエーテル等の多価フェノール類、エチレングリコール、ネオペンチルグリコール、グリセリン、トリメチロールプロパン、ポリプロピレングリコール等の多価アルコール類、エチレンジアミン、トリエチレンテトラミン、アニリン等のポリアミノ化合物、アジピン酸、フタル酸、イソフタル酸等の多価カルボキシ化合物等とエピクロルヒドリン又は2-メチルエピクロルヒドリンを反応させて得られるグリシジル型のエポキシ樹脂が例示される。また、ジシクロペンタジエンエポキサイド、ブタジエンダイマージエポキサイド等の脂肪族および脂環族エポキシ樹脂等が挙げられる。これらは単独又は2 種以上混合して使用することができる。
【００１０】
本発明に用いる硬化系成分としては、1 分子中に2 個以上の活性水素を有するものであれば特に制限することなく使用することができる。具体的なものとしては、例えば、ジエチレントリアミン、トリエチレンテトラミン、メタフェニレンジアミン、ジシアンジアミド、ポリアミドアミン等のポリアミノ化合物、また無水フタル酸、無水メチルナジック酸、ヘキサヒドロ無水フタル酸、無水ピロメリット酸等の有機酸無水物、そしてまたフェノールノボラック、クレゾールノボラック等のノボラック樹脂等が挙げられ、これらは単独又は2 種以上混合して使用することができる。
【００１１】
これらのエポキシ樹脂成分および硬化系成分の混合系は、室温でペースト状であり、沈降をなくするために25℃で100 ポイズ以上の粘度を有することが必要である。
【００１２】
次に、本発明でエポキシ樹脂ペーストに分散させ、導電層に異方導電性を付与するに用いる導電粒子としては、導電性カーボンや、無機又は有機粒子に銅、銀、ニッケル等の金属層を被覆したものもの、あるいは中空金属粒子等が挙げられる。これらは単独又は2 種以上混合して使用することができる。
【００１３】
導電粒子の各粒子の平均粒径は、7.0 μｍ以下でなければならない。7.0 μｍを超える平均粒径であると導通の異方性に欠陥が生ずるおそれがとともに導電粒子の沈降凝集についても好ましくない。また、導電粒子の比重は4.0 以下でなければならない。この比重は真比重であって蒿比重でなく、また例えばニッケル層被覆有機粒子のように複合導電粒子の場合は各粒子の平均真比重である。比重が4.0 を超えたものであると導電粒子の沈降凝集を生じて好ましくない。
【００１４】
【作用】
本発明の構成により、粒径および比重の規定された導電粒子は、一定以上の高粘度化されたペースト中に分散された状態を長期間維持することができ、優れた保存安定性が確保されるとともに、異方性導通の信頼性を高めることができる。
【００１５】
【発明の実施の形態】
以下、本発明の実施例を説明する。
実施例
液状エポキシ樹脂に硬化剤を分散させて得られたペーストにＮｉ被覆された樹脂粒子（粒径4 μｍ、比重2.5 ）を5 重量％混合し、粘度200 ポイズの異方導電性ペーストを得た。
【００１６】
比較例１
上記実施例のエポキシ系ペーストにＮｉ被覆された樹脂粒子（粒径10μｍ、比重2.5 ）を5 重量％混合し、粘度200 ポイズの異方導電性ペーストを得た。
【００１７】
比較例２
上記実施例のエポキシ系ペーストにＮｉ被覆された樹脂粒子（粒径4 μｍ、比重8.85）を5 重量％混合し、粘度200 ポイズの異方導電性ペーストを得た。
【００１８】
比較例３
上記実施例のエポキシ系ペーストにＮｉ被覆された樹脂粒子（粒径4 μｍ、比重2.5 ）を5 重量％混合し、粘度70ポイズの異方導電性ペーストを得た。
【００１９】
このように用意したペーストを作成後、高さ5 ｃｍのガラス瓶中に詰めて室温で20日間保存し、上部から0.5 ｃｍ部分の導電粒子含有率と底部から0.5 ｃｍ部分の導電粒子含有率を測定した。さらに液晶表示素子の透明電極と駆動外部回路のＴＡＢ電極間の接続に適用し、その異方性導通を確認した。
【００２０】
【表１】
【発明の効果】
本発明の異方性導電接着剤は、上記のように平均粒径が7.0 μｍ以下で比重が4.0 以下の導電粒子を含み、粘度を100 ポイズ以上にすることにより、粒子の沈降凝集が生ぜず、長期間の保存安定性を得ることが可能であるとともに異方性導通の信頼性を高めることができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement in a paste-like anisotropic conductive material used for connection between a transparent electrode terminal formed on a substrate of a liquid crystal display element and a wiring electrode terminal of a driving external circuit.
[0002]
[Prior art]
Conventionally, a sheet-like anisotropic conductive film carried on a polymer film has been used to electrically connect a transparent electrode and a wiring pattern of a driving external circuit in a liquid crystal display element. The anisotropic conductive film is an adhesive sheet in which metal particles such as solder and nickel or conductive particles obtained by plating the surface of resin particles with Ni are dispersed at a predetermined concentration in an insulating matrix.
[0003]
The anisotropic conductive film is used by peeling it from the polymer film as a carrier, placing it between two wiring patterns, and heating and pressurizing the panel substrate and driving external circuit substrate that support the wiring pattern, The metal particles or conductive particles conduct between the two wiring patterns and the insulating matrix melts, and the bonding is performed with the anisotropic conduction between the two wiring patterns fixed.
[0004]
In many cases, an epoxy-based thermosetting resin is used for the insulating matrix in this anisotropic conductive film in order to obtain connection reliability. Specifically, epoxy resin, polyamide resin, amines, imidazole are used. , Melamines, acid anhydrides and other curing agents are used.
[0005]
[Problems to be solved by the invention]
However, the conventional sheet-like anisotropic conductive film has problems such as poor peeling from the polymer film as the support carrier and the bonding form being regulated by the sheet shape. For this reason, liquid anisotropic conductive materials such as pastes have been proposed. However, when they are in a liquid state, the conductive particles cause sedimentation and aggregation over time due to the difference in specific gravity between the binder resin and the conductive particles during storage before use. Another problem occurred. In view of the problems in the prior art, an object of the present invention is to provide a liquid anisotropic conductive adhesive that hardly causes sedimentation and aggregation of conductive particles even after long-term storage.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention defines the average particle diameter of the conductive particles, defines the specific gravity of the conductive particles to a certain level or less, and further defines the viscosity at normal temperature as a paste to a certain level or more. The present invention has been completed by finding that it is possible to prevent sedimentation and aggregation of conductive particles even after storage for a long period of time.
[0007]
That is, the present invention is a paste-like conductive adhesive for forming an anisotropic conductive layer, in which conductive particles having an average particle diameter of 7.0 μm or less and a specific gravity of 4.0 or less are dispersed in an epoxy resin paste The anisotropic conductive adhesive is characterized in that the epoxy resin paste after dispersion of the conductive particles has a viscosity at 25 ° C. of 100 poise or more.
[0008]
Hereinafter, the present invention will be described in detail.
[0009]
The epoxy resin paste used in the present invention comprises a resin component having an epoxy group and a curing system component thereof. As the resin component having an epoxy group, a generally used epoxy resin can be used as long as it is a polyvalent epoxy resin having two or more epoxy groups in one molecule. Specifically, first, novolak resins such as phenol novolak and cresol novolak, polyhydric phenols such as bisphenol A, bisphenol F, resorcin, and bishydroxydiphenyl ether, ethylene glycol, neopentyl glycol, glycerin, trimethylolpropane, polypropylene Polyglycols such as glycol, polyamino compounds such as ethylenediamine, triethylenetetramine, and aniline, polycarboxyl compounds such as adipic acid, phthalic acid, and isophthalic acid and the like, and glycidyl type obtained by reacting epichlorohydrin or 2-methylepichlorohydrin The epoxy resin is exemplified. Moreover, aliphatic and alicyclic epoxy resins such as dicyclopentadiene epoxide and butadiene dimer epoxide are listed. These may be used alone or in combination of two or more.
[0010]
The curing system component used in the present invention can be used without particular limitation as long as it has two or more active hydrogens in one molecule. Specific examples include polyamino compounds such as diethylenetriamine, triethylenetetramine, metaphenylenediamine, dicyandiamide, and polyamideamine, and organic compounds such as phthalic anhydride, methyl nadic anhydride, hexahydrophthalic anhydride, and pyromellitic anhydride. Examples thereof include acid anhydrides, and novolak resins such as phenol novolak and cresol novolak, and these can be used alone or in combination of two or more.
[0011]
The mixed system of these epoxy resin component and curing system component is paste-like at room temperature, and it is necessary to have a viscosity of 100 poise or more at 25 ° C. in order to eliminate sedimentation.
[0012]
Next, the conductive particles dispersed in the epoxy resin paste in the present invention and used for imparting anisotropic conductivity to the conductive layer include conductive carbon, and metal layers such as copper, silver, nickel, etc. on the inorganic or organic particles. Examples include coated ones and hollow metal particles. These may be used alone or in combination of two or more.
[0013]
The average particle size of each particle of the conductive particles must be 7.0 μm or less. If the average particle size exceeds 7.0 μm, defects may occur in the anisotropy of conduction, and the sedimentation and aggregation of the conductive particles is not preferable. The specific gravity of the conductive particles must be 4.0 or less. This specific gravity is true specific gravity, not specific gravity, and in the case of composite conductive particles such as nickel layer-coated organic particles, it is the average true specific gravity of each particle. A specific gravity exceeding 4.0 is not preferable because the conductive particles precipitate and agglomerate.
[0014]
[Action]
According to the configuration of the present invention, the conductive particles having a specified particle diameter and specific gravity can be maintained in a state of being dispersed in a paste having a certain viscosity or higher for a long period of time, and excellent storage stability is ensured. In addition, the reliability of anisotropic conduction can be increased.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Examples of the present invention will be described below.
Example 5 wt% of Ni-coated resin particles (particle size 4 μm, specific gravity 2.5) are mixed with paste obtained by dispersing a curing agent in a liquid epoxy resin to obtain an anisotropic conductive paste having a viscosity of 200 poise. It was.
[0016]
Comparative Example 1
The above examples of the epoxy paste Ni coated resin particles (particle size 10 [mu] m, specific gravity 2.5) were mixed 5 wt% to obtain an anisotropic conductive paste of viscosity 200 poise.
[0017]
Comparative Example 2
The above examples of the epoxy paste Ni coated resin particles (particle size 4 [mu] m, specific gravity 8.85) were mixed 5 wt% to obtain a viscosity 200 poise anisotropic conductive paste.
[0018]
Comparative Example 3
The above examples of the epoxy paste Ni coated resin particles (particle size 4 [mu] m, specific gravity 2.5) were mixed 5 wt% to obtain an anisotropic conductive paste of viscosity 70 poise.
[0019]
After preparing the paste prepared in this way, it is packed in a 5 cm high glass bottle and stored at room temperature for 20 days, and the conductive particle content of the 0.5 cm portion from the top and the conductive particle content of the 0.5 cm portion from the bottom are measured. did. Furthermore, it applied to the connection between the transparent electrode of a liquid crystal display element and the TAB electrode of a drive external circuit, and confirmed the anisotropic conduction.
[0020]
[Table 1]
【The invention's effect】
The anisotropic conductive adhesive of the present invention contains conductive particles having an average particle diameter of 7.0 μm or less and a specific gravity of 4.0 or less as described above, and does not cause sedimentation and aggregation of particles by making the viscosity 100 poise or more. In addition, long-term storage stability can be obtained, and the reliability of anisotropic conduction can be increased.
Claims (1)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14865096A JP3753470B2 (en) | 1996-05-20 | 1996-05-20 | Anisotropic conductive adhesive |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14865096A JP3753470B2 (en) | 1996-05-20 | 1996-05-20 | Anisotropic conductive adhesive |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09306234A JPH09306234A (en) | 1997-11-28 |
| JP3753470B2 true JP3753470B2 (en) | 2006-03-08 |
Family
ID=15457556
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14865096A Expired - Fee Related JP3753470B2 (en) | 1996-05-20 | 1996-05-20 | Anisotropic conductive adhesive |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3753470B2 (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6812065B1 (en) | 1999-04-01 | 2004-11-02 | Mitsui Chemicals, Inc. | Anisotropic conductive paste |
| JP2001351345A (en) * | 2000-06-12 | 2001-12-21 | Alps Electric Co Ltd | Magnetic head device, and magnetic recording and/or reproducing device with the same loaded thereon |
| KR100527990B1 (en) * | 2001-11-30 | 2005-11-09 | 미쯔이카가쿠 가부시기가이샤 | Paste for circuit connection, anisotropic conductive paste and uses thereof |
| JP4735606B2 (en) * | 2007-06-14 | 2011-07-27 | 日本ゼオン株式会社 | Anisotropic conductive material |
| WO2011132658A1 (en) * | 2010-04-22 | 2011-10-27 | 積水化学工業株式会社 | Anisotropic conductive material and connection structure |
| JP5859783B2 (en) * | 2010-09-14 | 2016-02-16 | 積水化学工業株式会社 | Anisotropic conductive material and connection structure |
| JP2013077557A (en) * | 2011-09-13 | 2013-04-25 | Sekisui Chem Co Ltd | Anisotropic conductive material and connection structure |
| JP6130784B2 (en) * | 2012-12-28 | 2017-05-17 | 積水化学工業株式会社 | Organic-inorganic hybrid particles, conductive particles, conductive materials, and connection structures |
-
1996
- 1996-05-20 JP JP14865096A patent/JP3753470B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09306234A (en) | 1997-11-28 |
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