JP4867805B2 - Adhesive for electrode connection - Google Patents

Description

  The present invention relates to an electrode connecting adhesive for bonding and electrically connecting a wiring board or an electronic component provided with electrodes, circuits and the like.

  In recent years, electronic devices have been miniaturized and functionalized, and connection terminals in component parts (for example, electronic parts in liquid crystal products) have been miniaturized. For this reason, in the field of electronics mounting, film adhesives are widely used as various electrode connecting adhesives that can easily connect such terminals. For example, a flexible printed wiring board (FPC) on which a metal electrode made of gold-plated copper electrode is formed and a wiring board such as a glass substrate on which a wiring electrode made of ITO is formed, or an electronic component such as an IC chip Used for bonding of wiring boards.

  This electrode connecting adhesive is an adhesive in which conductive particles are dispersed in an insulating resin composition such as an epoxy resin, for example, and is sandwiched between objects to be connected, heated and pressurized to be connected. Glue the object. That is, the resin in the adhesive flows by heating and pressurizing, for example, simultaneously sealing the gap between the copper electrode formed on the surface of the flexible printed wiring board and the ITO electrode formed on the surface of the wiring board, Electrical connection is achieved by interposing a portion of the conductive particles between the copper electrode and the ITO electrode facing each other. In the electrode connecting adhesive, the conductive performance of reducing the resistance (connection resistance or conduction resistance) between the connected electrodes, which is relatively in the thickness direction of the electrode connecting adhesive, and for electrode connection Insulation performance is required to increase the resistance (insulation resistance) between electrodes adjacent in the surface direction of the adhesive.

In addition, by performing heat and pressure treatment via the electrode connecting adhesive, for example, when connecting the metal electrode of the flexible printed wiring board to the wiring electrode of the wiring board, the electrode connecting adhesive is applied to the wiring board. From the viewpoint of improving the adhesive strength of the electrode connecting adhesive to the wiring board (hereinafter sometimes referred to as “temporary adhesiveness”) when the temporary adhesion is performed. An adhesive for electrode connection containing an epoxy resin (that is, an epoxy resin having an average molecular weight of less than 500) has been proposed. More specifically, an adhesive for electrode connection containing a phenoxy resin having a skeleton such as biphenyl having an average molecular weight of 10,000 or more, a latent curing agent, and conductive particles, and having an average molecular weight of less than 500 naphthalene An electrode connecting adhesive containing a type epoxy resin is disclosed (for example, see Patent Document 1). An adhesive for electrode connection containing an epoxy resin, a latent curing agent, an inorganic filler having an average particle size of 500 nm or less, and conductive particles, wherein the epoxy resin is bisphenol A having an average molecular weight of about 400 An electrode connecting adhesive containing a liquid epoxy resin of a mold is disclosed (for example, see Patent Document 2).
JP 2005-294086 A JP 2006-196850 A

  However, in the conventional electrode connecting adhesive, in order to improve the temporary adhesion of the electrode connecting adhesive, the amount of the low molecular weight epoxy resin is increased with respect to the entire electrode connecting adhesive. Since it is necessary, the crosslinking density of the entire epoxy resin becomes excessively high. Therefore, repair (that is, peeling without causing damage or damage between the electrodes once connected due to misalignment of the connected electrodes, etc., removing the adhesive with a solvent, etc., and then using the adhesive again. When connecting the electrodes, there is a problem that the repairability of the electrode connecting adhesive is lowered and workability at the time of repairing is lowered. On the other hand, if the amount of low molecular weight epoxy resin is reduced to reduce the cross-linking density of the entire epoxy resin in order to improve repairability, the temporary adhesiveness of the above electrode connecting adhesive is sufficiently improved. For example, there is a problem that workability when connecting the flexible printed wiring board and the wiring board is lowered by performing the heat and pressure treatment through the electrode connecting adhesive. Therefore, the conventional electrode connecting adhesive has a problem that it is difficult to achieve both temporary adhesion and repairability.

  Therefore, the present invention has been made in view of the above-described problems, and can improve temporary adhesion and repairability, and by performing heat and pressure treatment via an electrode connecting adhesive, It aims at providing the adhesive agent for electrode connection which can improve the workability | operativity at the time of connecting a flexible printed wiring board and a wiring board.

To achieve the above object, the invention described in claim 1, in the electrode connecting adhesive containing a d epoxy resin and conductive particles and the latent curing agent, the electrode connecting adhesive is a polyvinyl butyral resin as well as containing, as the epoxy resin, the average molecular weight of the thermosetting below 500 epoxy resin, the average molecular weight of 500 to 4,000 of thermosetting epoxy resin, containing a phenoxy resin, and the phenoxy resin , said epoxy resin having an average molecular weight of less than 500, and the average molecular weight of 500 to 4,000 epoxy resin, the polyvinyl butyral resin and the latent curing agent, when the adhesive component, the adhesive component The amount of the epoxy resin having an average molecular weight of less than 500 is 20 wt% or more and 50 wt% or less, and the adhesive Amount of 4000 or less of the epoxy resin average molecular weight of 500 or more against the minute, is 15% by weight to 40% by weight, the amount of the polyvinyl butyral resin to the adhesive component, 1 wt% or more 8.7 wt% characterized in that it is less.

  According to this configuration, for example, a flexible printed wiring board can be obtained by performing heat and pressure treatment through an electrode connecting adhesive containing an epoxy resin as a main component and containing conductive particles and a latent curing agent. When connecting a metal electrode (for example, a copper electrode plated with gold) to a wiring electrode (for example, a copper electrode plated with gold), an epoxy resin having an average molecular weight of less than 500 is used to bond the electrodes. When the agent 2 is temporarily bonded onto the wiring substrate 1, the adhesive force (that is, temporary adhesion) of the electrode connecting adhesive 2 to the wiring substrate 1 can be improved. Therefore, workability when the metal electrode of the flexible printed wiring board is connected to the wiring electrode of the wiring board is improved.

  In addition, since the polyvinyl butyral resin is soluble in a solvent (toluene, acetone, alcohol, etc.) used for repair, the swelling property by the solvent is improved in the electrode connecting adhesive. In addition, since an epoxy resin having an average molecular weight of 500 or more and 4000 or less is taken into the network of the epoxy resin in the electrode connecting adhesive, the electrode connecting adhesive is used to improve the temporary adhesion of the electrode connecting adhesive. Even when the amount of the low molecular weight epoxy resin (epoxy resin having an average molecular weight of less than 500) is increased relative to the total amount of the resin, it is possible to prevent the crosslinking density of the entire epoxy resin from becoming excessively high. Become. Therefore, the repairability of the electrode connecting adhesive can be improved. As a result, it is possible to achieve both temporary adhesion and repairability improvement of the electrode connecting adhesive.

Furthermore, since the polyvinyl butyral resin has a hydroxyl group and the affinity of the hydroxyl group in the polyvinyl butyral resin to the wiring electrode and the metal electrode is high, the wiring electrode and the metal electrode are connected via an electrode connecting adhesive. It becomes possible to improve the adhesive force at the time. In addition, the connection reliability between the electrodes is improved with the effect of improving the adhesive strength of the electrode connection adhesive, the wiring electrode, and the metal electrode, and the improvement effect of the repair property due to the polyvinyl butyral resin. It becomes possible to make it.

The invention according to claim 2 is the electrode connecting adhesive according to claim 1 , wherein the conductive particles are a metal having a shape in which a large number of fine metal particles are connected in a straight chain, or a needle shape. It is characterized by being a powder.

  According to this configuration, in the surface direction of the electrode connecting adhesive, while maintaining insulation between adjacent electrodes to prevent a short circuit, in the thickness direction of the electrode connecting adhesive, a large number of wiring electrodes-metal It is possible to obtain a low resistance by electrically connecting the electrodes at a time and independently.

The invention described in claim 3 is the electrode connecting adhesive according to claim 2 , wherein the aspect ratio of the conductive particles is 5 or more. According to this configuration, when the electrode connecting adhesive is used, the contact probability between the conductive particles is increased. As a result, the wiring electrode and the metal electrode can be electrically connected without increasing the blending amount of the conductive particles.

A fourth aspect of the present invention is the electrode connecting adhesive according to any one of the first to third aspects , which has a film shape. According to this configuration, it becomes easy to handle the electrode connecting adhesive and, for example, work when connecting the wiring electrode and the metal electrode by performing a heat and pressure treatment via the electrode connecting adhesive. Improves.

Invention of Claim 5 is the adhesive agent for electrode connection of Claim 4 , Comprising: The major axis direction of electroconductive particle was orientated in the thickness direction of the adhesive agent which has a film shape, It is characterized by the above-mentioned. . According to the configuration, while maintaining insulation between adjacent electrodes to prevent a short circuit, it is possible to conduct conductive connection between a large number of wiring electrodes and metal electrodes at a time and independently of each other. However, it is further improved.

According to the present invention, for example, by performing heat and pressure treatment via an electrode connecting adhesive, the workability when connecting the metal electrode of the flexible printed wiring board to the wiring electrode of the wiring board is improved. Can do. Moreover, it becomes possible to make compatible the temporary adhesiveness and repair property of the adhesive agent for electrode connection. In addition, the connection reliability between the electrodes is improved with the effect of improving the adhesive strength of the electrode connection adhesive, the wiring electrode, and the metal electrode, and the improvement effect of the repair property due to the polyvinyl butyral resin. It becomes possible to make it.

  Hereinafter, a preferred embodiment of the present invention will be described. FIG. 1 is a cross-sectional view showing a wiring board on which a flexible printed wiring board is mounted with an electrode connecting adhesive according to the present embodiment. As a mounting method of a wiring board such as a flexible printed wiring board using the electrode connecting adhesive of the present embodiment, for example, via an electrode connecting adhesive mainly composed of an epoxy resin that is a thermosetting resin, By performing the heat and pressure treatment, the epoxy resin is cured, and the metal electrode of the flexible printed wiring board is connected to the wiring electrode of the wiring board.

  More specifically, as shown in FIG. 1, an epoxy resin that is an insulating thermosetting resin is a main component on a wiring substrate 1 such as a glass substrate, and contains a latent curing agent and conductive particles. A conductive electrode connecting adhesive 2 is placed, and the electrode connecting adhesive 2 is heated to a predetermined temperature and pressurized in the direction of the wiring substrate 1 with a predetermined pressure, and the electrode connecting adhesive 2 2 is temporarily bonded onto the wiring board 1. The electrode connecting adhesive 2 can be used in the form of a paste, but the electrode connecting adhesive 2 having a film shape can also be suitably used. Next, with the flexible printed wiring board 3 facing downward, while positioning the wiring electrode 4 formed on the surface of the wiring board 1 and the metal electrode 5 formed on the surface of the flexible printed wiring board 3, By placing the flexible printed wiring board 3 on the electrode connecting adhesive 2, the electrode connecting adhesive 2 is interposed between the wiring substrate 1 and the flexible printed wiring board 3. Next, by pressing the electrode connecting adhesive 2 with a predetermined pressure in the direction of the wiring board 1 through the flexible printed wiring board 3 in a state where the electrode connecting adhesive 2 is heated to a predetermined temperature, The electrode connecting adhesive 2 is heated and melted. As described above, since the electrode connecting adhesive 2 is mainly composed of an epoxy resin which is a thermosetting resin, the electrode connecting adhesive 2 is once softened when heated at the above temperature. However, it will be cured by continuing the heating. When a predetermined curing time of the electrode connecting adhesive 2 elapses, the state of maintaining the curing temperature of the electrode connecting adhesive 2 and the pressurized state are released, and cooling is started. The wiring electrode 4 and the metal electrode 5 are connected via the connecting adhesive 2, and the flexible printed wiring board 3 is mounted on the wiring board 1.

  In addition, as the metal electrode 5 of the present invention, for example, a metal foil such as a copper foil is laminated on the surface of the flexible printed wiring board 3, and the metal foil is exposed, etched, and plated by a conventional method. The formed copper electrode with gold plating is used. Further, as the wiring electrode 4, for example, a copper electrode on which the above-described gold plating is applied or an ITO electrode formed on the wiring substrate 1 is used.

  Here, in this embodiment, it is set as the structure which uses what contained the thermoplastic resin in the adhesive agent 2 for electrode connection, and the characteristic is that the polyvinyl butyral resin is contained as the said thermoplastic resin. By using such a polyvinyl butyral resin, the polyvinyl butyral resin is soluble in a solvent (toluene, acetone, alcohol, etc.) used for repair, and the electrode connection adhesive 2 swells with the solvent. Therefore, the repairability of the electrode connecting adhesive 2 can be improved.

Moreover, since polyvinyl butyral resin has a hydroxyl group and the affinity of the hydroxyl group in the polyvinyl butyral resin with respect to the wiring electrode 4 and the metal electrode 5 is high, the wiring electrode 4-metal electrode is interposed through the electrode connecting adhesive 2. It becomes possible to improve the adhesive force at the time of connecting five.

  In the present embodiment, the epoxy resin that is the main component of the electrode connecting adhesive 2 includes an epoxy resin having an average molecular weight of less than 500 and an epoxy resin having an average molecular weight of 500 or more and 4000 or less. . Here, the “average molecular weight” refers to a polystyrene-reduced weight average molecular weight obtained from gel permeation chromatography (GPC) developed with THF.

  By using an epoxy resin having an average molecular weight of less than 500, the electrode connecting adhesive 2 is pressurized at a predetermined pressure in the direction of the wiring board 1 in a state where the electrode connecting adhesive 2 is heated to a predetermined temperature. The adhesive force (that is, temporary adhesion) of the electrode connecting adhesive 2 to the wiring substrate 1 when temporarily bonding the substrate to the wiring substrate 1 is improved, and the crosslinking density is increased and the heat resistance is improved. can get. Moreover, the effect that it reacts rapidly with the above-mentioned latent hardening | curing agent at the time of a heating, and adhesive performance improves is acquired.

  Here, when the content of the epoxy resin having an average molecular weight of less than 500 increases, as described above, the crosslinking density becomes excessively high, and the repairability of the electrode connecting adhesive 2 may be lowered. On the other hand, when the content of the epoxy resin having an average molecular weight of less than 500 is small, the above temporary adhesiveness may not be sufficiently improved.

  Therefore, in this embodiment, an epoxy resin having an average molecular weight of 500 or more and 4000 or less is used as the epoxy resin in addition to the epoxy resin having an average molecular weight of less than 500. With such a configuration, an epoxy resin having a large average molecular weight (that is, an epoxy resin having an average molecular weight of 500 or more and 4000 or less) reacts with the resin component in the electrode connecting adhesive 2 to be taken into the epoxy resin network. It is. Accordingly, in order to improve the temporary adhesiveness of the electrode connecting adhesive 2, the amount of the low molecular weight epoxy resin (epoxy resin having an average molecular weight of less than 500) is increased with respect to the entire electrode connecting adhesive 2 Even so, it is possible to prevent the crosslinking density of the entire epoxy resin from becoming excessively high. As a result, in the electrode connecting adhesive 2 containing the polyvinyl butyral resin described above, the repairability of the electrode connecting adhesive 2 can be further improved.

  In this embodiment, such a configuration makes it possible to improve both the temporary adhesion and the repairability of the electrode connecting adhesive 2. That is, adhesive performance and repair performance can be obtained by combining the electrode connecting adhesive 2 with a polyvinyl butyral resin and using an epoxy resin having an average molecular weight of less than 500 and an epoxy resin having an average molecular weight of 500 or more and 4000 or less. It becomes possible to balance.

In addition, in this embodiment, it is set as the structure which makes the compounding quantity of the epoxy resin with an average molecular weight less than 500 with respect to an adhesive agent component 20 weight% or more and 50 weight% or less. This is because when the blending amount of the epoxy resin having an average molecular weight of less than 500 is less than 20% by weight, the temporary adhesiveness of the electrode connecting adhesive 2 may not be sufficiently improved, and when it is greater than 50% by weight. This is because the above-mentioned cross-linking density becomes excessively high and the repairability may be lowered. The adhesive component does not include conductive particles dispersed in the electrode connecting adhesive 2.

In the present embodiment, the blending amount of the epoxy resin having an average molecular weight of 500 or more and 4000 or less with respect to the adhesive component is set to 15% by weight or more and 40% by weight or less. This is because when the blending amount of the epoxy resin having an average molecular weight of 500 or more and 4000 or less is less than 15% by weight, the increase in the above-mentioned crosslinking density may not be sufficiently suppressed, and the effect of improving the repair property is obtained. This is because there are cases where it cannot be obtained sufficiently. Moreover, when the compounding quantity of the epoxy resin whose average molecular weight is 500-4000 is larger than 40 weight%, the reactivity with the resin component in the electrode connection adhesive 2 falls, and an average molecular weight is 500-4000. Since the epoxy resin is difficult to be taken into the epoxy resin network, the effect of preventing the crosslinking density of the entire epoxy resin from becoming excessively high may not be sufficiently exhibited. This is because the connection resistance between the wiring electrodes 5 and the metal electrode 5 may be lowered in connection resistance.

  As the electrode connecting adhesive 2 used in the present invention, an epoxy resin which is an insulating thermosetting resin, which has been conventionally used for connecting the wiring board 1 and the flexible printed wiring board 3, is used as a main component. A resin in which conductive particles are dispersed in the resin can be used. For example, an epoxy resin in which powder of conductive particles such as nickel, copper, silver, gold, or graphite is dispersed can be used.

  In addition, there is no restriction | limiting in particular in the kind of epoxy resin to be used, What kind of thing can be used if it is an epoxy resin which has the above-mentioned average molecular weight. For example, bisphenol A type, F type, S type, AD type, or a copolymer type epoxy resin of bisphenol A type and bisphenol F type, naphthalene type epoxy resin, novolac type epoxy resin, biphenyl type epoxy resin, dicyclo A pentadiene type epoxy resin or the like can be used. A phenoxy resin that is a high molecular weight epoxy resin can also be used.

Moreover, it is preferable that the compounding quantity of polyvinyl butyral with respect to an adhesive component shall be 1 to 30 weight%. This is because, when the blending amount of polyvinyl butyral is less than 1% by weight, the above-described effect of improving the adhesive force between the electrode connecting adhesive 2, the wiring electrode 4, and the metal electrode 5 by the polyvinyl butyral resin, and This is because the effect of improving the repairability may not be sufficiently exhibited. Further, when the amount of polyvinyl butyral is larger than 30% by weight, the glass transition temperature of the epoxy resin as the main component is lowered, so that the aggregation of the epoxy resin for maintaining the connection between the wiring electrode 4 and the metal electrode 5 is achieved. This is because the force is not sufficient, and as a result, the connection reliability between the electrodes may decrease. In addition, the above-mentioned “glass transition temperature” means a physical property value of the electrode connecting adhesive 2 measured using a dynamic viscoelasticity measuring device (DMA).

  Further, as the electrode connecting adhesive 2 used in the present invention, an adhesive containing a latent curing agent is used. This latent curing agent is a curing agent that is excellent in storage stability at a low temperature and hardly undergoes a curing reaction at room temperature, but rapidly undergoes a curing reaction by heat or light. As this latent curing agent, imidazole series, hydrazide series, boron trifluoride-amine complex, amine imide, polyamine series, tertiary amine, alkyl urea series and other amine series, dicyandiamide series, acid anhydride series, phenol series These modified products are exemplified, and these can be used alone or as a mixture of two or more.

  Among these latent curing agents, an imidazole-based latent curing agent is preferably used from the viewpoint that it is excellent in storage stability at a low temperature and fast curability. As the imidazole-based latent curing agent, a known imidazole-based latent curing agent can be used. More specifically, an adduct of an imidazole compound with an epoxy resin is exemplified. Examples of the imidazole compound include imidazole, 2-methylimidazole, 2-ethylimidazole, 2-propylimidazole, 2-dodecylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, and 4-methylimidazole. In addition, it is good also as a structure which uses the epoxy resin which has the above-mentioned average molecular weight for the epoxy resin of an imidazole compound.

  In particular, these latent curing agents coated with a polymer material such as polyurethane and polyester, a metal thin film such as nickel and copper, and an inorganic material such as calcium silicate, This is preferable because it is possible to achieve both contradictory properties of storage stability and fast curability. Therefore, a microcapsule type imidazole-based latent curing agent is particularly preferable.

  Further, as shown in FIG. 2, an anisotropic conductive adhesive containing conductive particles 6 can be used as the electrode connecting adhesive 2. More specifically, as the anisotropic conductive adhesive, for example, the above-described epoxy resin is the main component, and fine metal particles (for example, spherical metal fine particles or spherical particles plated with metal) are contained in the resin. Use is made of a dispersion of conductive particles 6 formed of metal powder having a large number of metal fine particles (resin particles), linearly connected, or needle-shaped, so-called large aspect ratio. be able to. The aspect ratio referred to here is the ratio of the short diameter (the length of the cross section of the conductive particles 6) R and the long diameter (the length of the conductive particles 6) L of the conductive particles 6 shown in FIG. Say.

  By using such conductive particles 6, as the anisotropic conductive adhesive, the surface direction of the electrode connecting adhesive 2 (the direction perpendicular to the thickness direction X and the direction of the arrow Y in FIG. 2). In the thickness direction X, a large number of wiring electrodes 4 and metal electrodes 5 are connected at a time and independently at a low resistance while maintaining insulation between adjacent electrodes to prevent short circuit. Can be obtained.

  The aspect ratio of the conductive particles 6 is preferably 5 or more. By using such conductive particles 6, when an anisotropic conductive adhesive is used as the electrode connecting adhesive 2, the contact probability between the conductive particles 6 is increased. Therefore, the wiring electrode 4 and the metal electrode 5 can be electrically connected without increasing the blending amount of the conductive particles 6.

  In this anisotropic conductive adhesive, the magnetic field applied to the thickness direction X of the anisotropic conductive adhesive when the direction of the long diameter L of the conductive particles 6 is formed into a film-like anisotropic conductive adhesive is formed. It is preferable to use it in the thickness direction X by passing through the inside. By having such an orientation, the above-described insulation between adjacent electrodes is maintained to prevent a short circuit, and a large number of wiring electrodes 4 to metal electrodes 5 are electrically connected to each other at once and independently. The effect that it becomes possible to improve is further improved.

  In addition, the metal powder used in the present invention preferably contains a ferromagnetic material in part, such as a single metal having ferromagnetism, two or more kinds of alloys having ferromagnetism, a metal having ferromagnetism and others. It is preferably any one of an alloy with the above metal and a composite containing a metal having ferromagnetism. This is because the use of a ferromagnetic metal makes it possible to orient the conductive particles 6 using a magnetic field due to the magnetism of the metal itself. For example, nickel, iron, cobalt, and two or more kinds of alloys containing these can be used.

  The aspect ratio of the conductive particles 6 is directly measured by a method such as observation with a CCD microscope. In the case of the conductive particles 6 whose cross section is not a circle, the aspect ratio is obtained by setting the maximum length of the cross section as the short diameter. The conductive particles 6 do not necessarily have a straight shape, and can be used without any problems even if they are slightly bent or branched. In this case, the aspect ratio is obtained by setting the maximum length of the conductive particles 6 as the major axis.

According to the present embodiment described above, the following effects can be obtained.
(1) In this embodiment, in the electrode connection adhesive 2 containing an epoxy resin which is an insulating thermosetting resin as a main component and containing conductive particles and a latent curing agent, the electrode connection adhesive 2 is configured to contain a polyvinyl butyral resin. The epoxy resin contains an epoxy resin having an average molecular weight of less than 500 and an epoxy resin having an average molecular weight of 500 or more and 4000 or less. And the compounding quantity of the epoxy resin whose average molecular weight with respect to an adhesive agent component is less than 500 is 20 weight% or more and 50 weight% or less, and the compounding quantity whose said average molecular weight with respect to an adhesive agent component is 500 or more and 4000 or less is 15 weight%. It is set as the structure made into 40 weight% or less above. Accordingly, it is possible to improve the adhesive force of the electrode connecting adhesive 2 to the wiring substrate 1 when the electrode connecting adhesive 2 is temporarily bonded onto the wiring substrate 1 with an epoxy resin having an average molecular weight of less than 500. Thus, workability when the metal electrode 5 of the flexible printed wiring board 3 is connected to the wiring electrode 4 of the wiring board 1 is improved.

  Moreover, the swelling property by a solvent improves in the adhesive agent 2 for electrode connection by polyvinyl butyral resin. In addition, since an epoxy resin having an average molecular weight of 500 or more and 4000 or less is taken into the network of the epoxy resin in the electrode connecting adhesive 2, the blending of the epoxy resin having an average molecular weight of less than 500 with respect to the entire electrode connecting adhesive Even when the amount is increased, it is possible to prevent the crosslinking density of the entire epoxy resin from becoming excessively high. Therefore, the repairability of the electrode connecting adhesive 2 can be improved. As a result, it is possible to achieve both the temporary adhesiveness and repairability of the electrode connecting adhesive 2.

  Furthermore, since the affinity of the hydroxyl group in the polyvinyl butyral resin to the wiring electrode and the metal electrode is high, the adhesion force when connecting the wiring electrode 4 to the metal electrode 5 through the electrode connecting adhesive 2 is improved. Is possible.

(2) In this embodiment, it is set as the structure which makes the compounding quantity of the polyvinyl butyral with respect to an adhesive agent component 1 weight% or more and 30 weight% or less. Accordingly, the connection reliability between the electrodes can be obtained in a state where the effect of improving the adhesive force of the electrode connecting adhesive 2, the wiring electrode 4 and the metal electrode 5 and the effect of improving the repair property are sufficiently exerted by the polyvinyl butyral resin. It becomes possible to improve the property.

  (3) In the present embodiment, as the conductive particles 6, a metal powder having a shape in which a number of fine metal particles are connected in a straight chain or a needle shape is used. Therefore, in the surface direction Y of the electrode connecting adhesive 2, while maintaining insulation between adjacent electrodes to prevent a short circuit, in the thickness direction X of the electrode connecting adhesive 2, a large number of wiring electrodes 4- It is possible to obtain a low resistance by connecting the metal electrodes 5 at a time and independently of each other.

  (4) In the present embodiment, the aspect ratio of the conductive particles 6 is 5 or more. Therefore, when an anisotropic conductive adhesive is used as the electrode connecting adhesive 2, the contact probability between the conductive particles 6 is increased. As a result, the wiring electrode 4 and the metal electrode 5 can be electrically connected without increasing the blending amount of the conductive particles 6.

  (5) In this embodiment, it is set as the structure which uses the adhesive agent 2 for electrode connection which has a film shape. Therefore, handling of the electrode connecting adhesive 2 is facilitated, and workability when the wiring electrode 4 and the metal electrode 5 are connected by the electrode connecting adhesive 2 is improved.

  (6) In this embodiment, it is set as the structure which orientates the direction of the long diameter L of the electroconductive particle 6 in the thickness direction X of the adhesive agent 2 for electrode connection which has a film shape. Therefore, it is possible to electrically connect the wiring electrodes 4 to the metal electrodes 5 at once and independently, while maintaining the above-described insulation between adjacent electrodes and preventing a short circuit. The effect is further improved.

In addition, you may change the said embodiment as follows.
In the above embodiment, the metal electrode 5 of the flexible printed wiring board 3 is connected to the wiring electrode 4 of the wiring board 1 via the electrode connecting adhesive 2, but the electrode connecting adhesive of the present invention 2 may be used, for example, for connection between the protruding electrodes (or bumps) of an electronic component such as an IC chip and the wiring electrodes 4 of the wiring board 1.

  In addition, the thermoplastic resin contained in the electrode connecting adhesive 2 may contain, for example, polyurethane, polyester, polystyrene, polysiloxane, polyvinyl acetal, etc. in addition to the above-mentioned polyvinyl butyral.

  Below, this invention is demonstrated based on an Example and a comparative example. In addition, this invention is not limited to these Examples, These Examples can be changed and changed based on the meaning of this invention, and they are excluded from the scope of the present invention. is not.

Example 1
(Production of adhesive)
As the conductive particles, linear nickel fine particles having a long diameter L distribution of 1 μm to 8 μm and a short diameter R distribution of 0.1 μm to 0.4 μm were used. In addition, as the epoxy resin, (1) phenoxy resin [manufactured by Japan Epoxy Resin Co., Ltd., trade name Epicoat 1256, average molecular weight 50000], (2) bisphenol A type solid epoxy resin [manufactured by Japan Epoxy Resin Co., Ltd., Trade name Epicoat 1002, average molecular weight 1200], and (3) naphthalene type epoxy resin [Dainippon Ink Chemical Co., Ltd., trade name Epicron HP4032, average molecular weight 270] were used. As the thermoplastic resin, (4) polyvinyl butyral resin [manufactured by Sekisui Chemical Co., Ltd., trade name ESREC BM-1] is used, and as the latent curing agent, (5) microcapsule type imidazole-based curing is used. Agent (made by Asahi Kasei Epoxy Co., Ltd., trade name Novacure HX3941, 13% by weight of bisphenol A type epoxy resin having an average molecular weight of 380, and 52% by weight of bisphenol F type epoxy resin having an average molecular weight of 350), These (1) to (5) were blended in a weight ratio of (1) 30 / (2) 40 / (3) 20 / (4) 10 / (5) 35. The phenoxy resin, the epoxy resin, the polyvinyl butyral resin, and the latent curing agent blended in this way are referred to as “adhesive components”. In addition, the compounding quantity of the epoxy resin whose average molecular weight is less than 500 is 31.7 weight%, and the compounding quantity of the epoxy resin whose average molecular weight is 500 or more and 4000 or less is 29.6 weight%. Moreover, the compounding quantity of polyvinyl butyral resin is 7.4 weight%.

  These epoxy resin, polyvinyl butyral resin, and latent curing agent are dissolved and dispersed in 2-ethoxyethyl acetate (boiling point: 156 ° C.), and then kneaded with three rolls to obtain a solid content of 40 A solution that was weight percent was made. To this solution, the Ni powder was added so that the metal filling ratio represented by the ratio of the total solid content (Ni powder + resin) was 0.2% by volume, and then stirred using a centrifugal mixer. As a result, Ni powder was uniformly dispersed to produce a composite material for an adhesive. Next, after applying this composite material on a PET film subjected to a release treatment using a doctor knife, it is dried and solidified at 60 ° C. for 30 minutes in a magnetic field having a magnetic flux density of 100 mT, whereby linear particles in the film are obtained. An electrode connecting adhesive having anisotropic conductivity in the form of a film having a thickness of 35 μm was prepared.

(Temporary adhesion evaluation)
A rigid wiring board (glass cloth epoxy substrate) having a width of 100 μm and a height of 35 μm and 50 gold-plated copper electrodes arranged at intervals of 100 μm was prepared. Next, the adhesive for electrode connection produced on the above-mentioned PET film is placed on the rigid wiring board, and 1 MPa in the direction of the wiring substrate 1 in a state where the adhesive for electrode connection is heated to 60 ° C. The pressure was applied for 10 seconds to try to transfer the electrode connecting adhesive from the PET film to the rigid wiring board (that is, temporary bonding of the electrode connecting adhesive onto the rigid wiring board). Then, when the electrode connecting adhesive could be transferred from the PET film to the rigid wiring board and the electrode connecting adhesive could be placed on the rigid wiring board, it was determined that the temporary adhesiveness was good. The results are shown in Table 1.

(Repairability evaluation)
50 printed flexible printed wiring boards with 100 μm wide and 18 μm high gold plated copper electrodes arranged at 100 μm intervals and 100 μm wide and 35 μm high gold plated copper electrodes at 100 μm intervals 50 rigid wiring boards (glass cloth epoxy substrates) arranged were prepared. Next, the adhesive prepared between the flexible printed wiring board and the glass substrate is sandwiched, and heated and heated to 200 ° C., the pressure is applied at a pressure of 4 MPa for 15 seconds, and the bonded body of the flexible printed wiring board and the glass substrate is bonded. Obtained. Next, in a state where the joined body is heated to 200 ° C., the flexible printed wiring board is peeled from the glass substrate, and the adhesive remaining on the copper electrode of the glass substrate is mixed with a mixed solvent of methyl ethyl ketone and ethanol (mixing ratio is 70/30) was wiped off with a dipped cotton swab to remove the adhesive remaining on the copper electrode of the glass substrate. Next, the above-mentioned prepared adhesive is sandwiched again between the above-mentioned flexible printed wiring board and the glass substrate from which the adhesive has been removed, and is pressed at a pressure of 4 MPa for 15 seconds while being heated to 200 ° C. The bonded body of the flexible printed wiring board and the glass substrate was obtained by bonding. Next, in this joined body, when a constant current of 1 mA is applied, the resistance value of 10 consecutive points connected via the adhesive and the copper electrode is obtained by the four-terminal method, and the obtained value is divided by 10 Thus, the connection resistance per connected place (hereinafter referred to as “initial connection resistance”) was obtained. And this evaluation was repeated 10 times and the average value of initial connection resistance was calculated | required. And the case where the said initial connection resistance was 1 ohm or less was judged as a thing with favorable repair property. Moreover, the number of times of wiping when wiping with the cotton swab dipped in the above mixed solvent (that is, the number of times of rub against the adhesive remaining on the copper electrode of the glass substrate) is used as an index of the time required for repair, The working time for repairing was evaluated. When the number of wiping times was 50 times or less, the work time for repairing was determined to be short and good. The results are shown in Table 1.

(Connection reliability evaluation)
For connection reliability evaluation, first, the above-mentioned joined body (before peeling the flexible printed wiring board from the glass substrate) was prepared, and the temperature was set to 85 ° C. and the humidity was set to 85%. Then, the joined body was taken out from the constant temperature and humidity chamber, and the average value of the connection resistance was obtained again in the same manner as described above. And when the said connection resistance was 3 ohms or less, it was judged that the connection reliability between electrodes was favorable. The results are shown in Table 1.

(Example 2)
(1) Phenoxy resin [manufactured by Japan Epoxy Resin Co., Ltd., trade name: Epicoat 1256, average molecular weight 50000], (2) bisphenol A type solid epoxy resin [Japan Epoxy Resin Co., Ltd.] described in Example 1 above Product name Epicoat 1002, average molecular weight 1200], (3) naphthalene type epoxy resin [Dainippon Ink Chemical Co., Ltd., product name Epicron HP4032, average molecular weight 270], (4) polyvinyl butyral resin [Sekisui Chemical Co., Ltd.] (Trade name: S-Rec BM-1), and (5) microcapsule type imidazole curing agent (trade name: NOVACURE HX3941, trade name: NOVACURE HX3941, an average molecular weight of 380 bisphenol A type epoxy resin) %, Average molecular weight 350 bisphenol F type epoxy Except that the blending amount of the resin containing 52% by weight of the resin is changed to a ratio of (1) 30 / (2) 40 / (3) 50 / (4) 10 / (5) 35 by weight ratio. In the same manner as in Example 1, a film-like adhesive for electrode connection having an anisotropic conductivity having a thickness of 35 μm was produced to obtain a joined body of a flexible printed wiring board and a glass substrate. Then, the above results of performing temporary adhesion evaluation, repairability evaluation, and connection reliability evaluation under the same conditions as in Example 1 are shown in Table 1. In addition, the compounding quantity of the epoxy resin whose average molecular weight is less than 500 is 44.1 weight%, and the compounding quantity of the epoxy resin whose average molecular weight is 500 or more and 4000 or less is 24.2 weight%. Moreover, the compounding quantity of polyvinyl butyral resin is 6.1 weight%.

(Example 3)
(1) Phenoxy resin [manufactured by Japan Epoxy Resin Co., Ltd., trade name: Epicoat 1256, average molecular weight 50000], (2) bisphenol A type solid epoxy resin [Japan Epoxy Resin Co., Ltd.] described in Example 1 above Product name Epicoat 1002, average molecular weight 1200], (3) naphthalene type epoxy resin [Dainippon Ink Chemical Co., Ltd., product name Epicron HP4032, average molecular weight 270], (4) polyvinyl butyral resin [Sekisui Chemical Co., Ltd.] (Trade name: S-Rec BM-1), and (5) microcapsule type imidazole curing agent (trade name: NOVACURE HX3941, trade name: NOVACURE HX3941, an average molecular weight of 380 bisphenol A type epoxy resin) %, Average molecular weight 350 bisphenol F type epoxy Except that the blending amount of the resin containing 52% by weight of the resin is changed to a ratio of (1) 30 / (2) 40 / (3) 10 / (4) 10 / (5) 25 in weight ratio, In the same manner as in Example 1, a film-like adhesive for electrode connection having an anisotropic conductivity having a thickness of 35 μm was produced to obtain a joined body of a flexible printed wiring board and a glass substrate. Then, the above results of performing temporary adhesion evaluation, repairability evaluation, and connection reliability evaluation under the same conditions as in Example 1 are shown in Table 1. The blending amount of the epoxy resin having an average molecular weight of less than 500 is 22.8% by weight, and the blending amount of the epoxy resin having an average molecular weight of 500 or more and 4000 or less is 34.8% by weight. Moreover, the compounding quantity of polyvinyl butyral resin is 8.7 weight%.

Example 4
(1) Phenoxy resin [manufactured by Japan Epoxy Resin Co., Ltd., trade name: Epicoat 1256, average molecular weight 50000], (2) bisphenol A type solid epoxy resin [Japan Epoxy Resin Co., Ltd.] described in Example 1 above Product name Epicoat 1002, average molecular weight 1200], (3) naphthalene type epoxy resin [Dainippon Ink Chemical Co., Ltd., product name Epicron HP4032, average molecular weight 270], (4) polyvinyl butyral resin [Sekisui Chemical Co., Ltd.] (Trade name: S-Rec BM-1), and (5) microcapsule type imidazole curing agent (trade name: NOVACURE HX3941, trade name: NOVACURE HX3941, an average molecular weight of 380 bisphenol A type epoxy resin) %, Average molecular weight 350 bisphenol F type epoxy Except that the blending amount of the resin containing 52% by weight of the resin is changed to a ratio of (1) 30 / (2) 20 / (3) 20 / (4) 10 / (5) 35 by weight ratio. In the same manner as in Example 1, a film-like adhesive for electrode connection having an anisotropic conductivity having a thickness of 35 μm was produced to obtain a joined body of a flexible printed wiring board and a glass substrate. Then, the above results of performing temporary adhesion evaluation, repairability evaluation, and connection reliability evaluation under the same conditions as in Example 1 are shown in Table 1. In addition, the compounding quantity of the epoxy resin whose average molecular weight is less than 500 is 37.2 weight%, and the compounding quantity of the epoxy resin whose average molecular weight is 500 or more and 4000 or less is 17.4 weight%. Moreover, the compounding quantity of polyvinyl butyral resin is 8.7 weight%.

(Example 5)
(1) Phenoxy resin [manufactured by Japan Epoxy Resin Co., Ltd., trade name: Epicoat 1256, average molecular weight 50000], (2) bisphenol A type solid epoxy resin [Japan Epoxy Resin Co., Ltd.] described in Example 1 above Product name Epicoat 1002, average molecular weight 1200], (3) naphthalene type epoxy resin [Dainippon Ink Chemical Co., Ltd., product name Epicron HP4032, average molecular weight 270], (4) polyvinyl butyral resin [Sekisui Chemical Co., Ltd.] (Trade name: S-Rec BM-1), and (5) microcapsule type imidazole curing agent (trade name: NOVACURE HX3941, trade name: NOVACURE HX3941, an average molecular weight of 380 bisphenol A type epoxy resin) %, Average molecular weight 350 bisphenol F type epoxy Except that the blending amount of the resin containing 52% by weight of the resin is changed to a ratio of (1) 30 / (2) 50 / (3) 20 / (4) 10 / (5) 35 by weight ratio, In the same manner as in Example 1, a film-like adhesive for electrode connection having an anisotropic conductivity having a thickness of 35 μm was produced to obtain a joined body of a flexible printed wiring board and a glass substrate. Then, the above results of performing temporary adhesion evaluation, repairability evaluation, and connection reliability evaluation under the same conditions as in Example 1 are shown in Table 1. In addition, the compounding quantity of the epoxy resin whose average molecular weight is less than 500 is 29.5 weight%, and the compounding quantity of the epoxy resin whose average molecular weight is 500 or more and 4000 or less is 34.5 weight%. Moreover, the compounding quantity of polyvinyl butyral resin is 6.9 weight%.

( Reference Example 1 )
(1) Phenoxy resin [manufactured by Japan Epoxy Resin Co., Ltd., trade name: Epicoat 1256, average molecular weight 50000], (2) bisphenol A type solid epoxy resin [Japan Epoxy Resin Co., Ltd.] described in Example 1 above Product name Epicoat 1002, average molecular weight 1200], (3) naphthalene type epoxy resin [Dainippon Ink Chemical Co., Ltd., product name Epicron HP4032, average molecular weight 270], (4) polyvinyl butyral resin [Sekisui Chemical Co., Ltd.] (Trade name: S-Rec BM-1), and (5) microcapsule type imidazole curing agent (trade name: NOVACURE HX3941, trade name: NOVACURE HX3941, an average molecular weight of 380 bisphenol A type epoxy resin) %, Average molecular weight 350 bisphenol F type epoxy Except that the blending amount of the resin containing 52% by weight of the resin is changed to a ratio of (1) 30 / (2) 40 / (3) 20 / (4) 35 / (5) 35 by weight ratio. In the same manner as in Example 1, a film-like adhesive for electrode connection having an anisotropic conductivity having a thickness of 35 μm was produced to obtain a joined body of a flexible printed wiring board and a glass substrate. Then, the above results of performing temporary adhesion evaluation, repairability evaluation, and connection reliability evaluation under the same conditions as in Example 1 are shown in Table 1. In addition, the compounding quantity of the epoxy resin whose average molecular weight is less than 500 is 26.7 weight%, and the compounding quantity of the epoxy resin whose average molecular weight is 500 or more and 4000 or less is 25.0 weight%. Moreover, the compounding quantity of polyvinyl butyral resin is 21.9 weight%.

(Comparative Example 1)
(1) Phenoxy resin [manufactured by Japan Epoxy Resin Co., Ltd., trade name: Epicoat 1256, average molecular weight 50000], (2) bisphenol A type solid epoxy resin [Japan Epoxy Resin Co., Ltd.] described in Example 1 above Product name epicoat 1002, average molecular weight 1200], (3) naphthalene type epoxy resin [manufactured by Dainippon Ink and Chemicals, trade name epicron HP4032, average molecular weight 270], and (5) microcapsule type imidazole-based curing. Amount of the agent (made by Asahi Kasei Epoxy Co., Ltd., trade name Novacure HX3941, 13% by weight of bisphenol A type epoxy resin having an average molecular weight of 380 and 52% by weight of bisphenol F type epoxy resin having an average molecular weight of 350) (1) 40 / (2) 30 / (3) 5 by weight ratio (5) While changing to the ratio of 15, (4) Polyvinyl butyral resin used in Example 1 [Sekisui Chemical Co., Ltd., trade name ESREC BM-1] was used, except that it was not used. In the same manner as in Example 1, a film-like electrode conductive adhesive having an anisotropic conductivity having a thickness of 35 μm was prepared, and a joined body of a flexible printed wiring board and a glass substrate was obtained. Then, the above results of performing temporary adhesion evaluation, repairability evaluation, and connection reliability evaluation under the same conditions as in Example 1 are shown in Table 1. In addition, the compounding quantity of the epoxy resin whose average molecular weight is less than 500 is 16.4 weight%, and the compounding quantity of the epoxy resin whose average molecular weight is 500 or more and 4000 or less is 33.3% by weight.

(Comparative Example 2)
(1) Phenoxy resin [manufactured by Japan Epoxy Resin Co., Ltd., trade name: Epicoat 1256, average molecular weight 50000], (2) bisphenol A type solid epoxy resin [Japan Epoxy Resin Co., Ltd.] described in Example 1 above Product name epicoat 1002, average molecular weight 1200], (3) naphthalene type epoxy resin [manufactured by Dainippon Ink and Chemicals, trade name epicron HP4032, average molecular weight 270], and (5) microcapsule type imidazole-based curing. Amount of the agent (made by Asahi Kasei Epoxy Co., Ltd., trade name Novacure HX3941, 13% by weight of bisphenol A type epoxy resin having an average molecular weight of 380 and 52% by weight of bisphenol F type epoxy resin having an average molecular weight of 350) (1) 30 / (2) 70 / (3) 2 by weight ratio / (5) Implemented except that the ratio was changed to 35 and (4) Polyvinyl butyral resin [Sekisui Chemical Co., Ltd., trade name ESREC BM-1] used in Example 1 was not used. In the same manner as in Example 1, a film-like adhesive for electrode connection having an anisotropic conductivity having a thickness of 35 μm was prepared, and a joined body of a flexible printed wiring board and a glass substrate was obtained. Then, the above results of performing temporary adhesion evaluation, repairability evaluation, and connection reliability evaluation under the same conditions as in Example 1 are shown in Table 1. In addition, the compounding quantity of the epoxy resin whose average molecular weight is less than 500 is 27.6 weight%, and the compounding quantity of the epoxy resin whose average molecular weight is 500 or more and 4000 or less is 45.2 weight%.

(Comparative Example 3)
As the conductive particles, linear nickel fine particles having a long diameter L distribution of 1 μm to 8 μm and a short diameter R distribution of 0.1 μm to 0.4 μm were used. Moreover, as an epoxy resin, (1) Phenoxy resin [made by Japan Epoxy Resin Co., Ltd., brand name Epicoat 1256, average molecular weight 50000], (2) Naphthalene type epoxy resin [made by Japan Epoxy Resin Co., Ltd., brand name Epicoat 1032, average molecular weight 680], and (3) naphthalene type epoxy resin [Dainippon Ink Chemical Co., Ltd., trade name Epicron HP4032, average molecular weight 270] was used. In addition, as the latent curing agent, (4) microcapsule type imidazole curing agent [trade name Novacure HX3941, manufactured by Asahi Kasei Epoxy Co., Ltd., 13% by weight of bisphenol A type epoxy resin with an average molecular weight of 380, average molecular weight of 350 Containing 52% by weight of a bisphenol F-type epoxy resin], and (1) to (4) are weight ratios of (1) 40 / (2) 20 / (3) 30 / (4) 10 Formulated in proportions. In addition, the compounding quantity of the epoxy resin whose average molecular weight is less than 500 is 36.5 weight%, and the compounding quantity of the epoxy resin whose average molecular weight is 500 or more and 4000 or less is 20.0 weight%. Next, in the same manner as in Example 1 described above, a film-like adhesive for electrode connection having an anisotropic conductivity having a thickness of 35 μm was prepared, and a joined body of a flexible printed wiring board and a glass substrate was obtained. Then, the above results of performing temporary adhesion evaluation, repairability evaluation, and connection reliability evaluation under the same conditions as in Example 1 are shown in Table 1.

(Comparative Example 4)
As the conductive particles, linear nickel fine particles having a long diameter L distribution of 1 μm to 8 μm and a short diameter R distribution of 0.1 μm to 0.4 μm were used. Epoxy resins include (1) an epoxy resin having a biphenyl skeleton introduced therein (trade name Epicoat YL6954, average molecular weight 39000, manufactured by Japan Epoxy Resin Co., Ltd.), and (2) a naphthalene type epoxy resin [Dainippon Ink Chemical Co., Ltd. (Trade name) Epicron HP4032, average molecular weight 270]. In addition, as the latent curing agent, (3) microcapsule type imidazole curing agent [trade name Novacure HX3941, manufactured by Asahi Kasei Epoxy Co., Ltd., 13% by weight of bisphenol A type epoxy resin with an average molecular weight of 380, average molecular weight of 350 (1) to (3) were blended at a ratio of (1) 50 / (2) 40 / (3) 10 by weight ratio. In addition, the compounding quantity of the epoxy resin whose average molecular weight is less than 500 is 46.5 weight%. Next, in the same manner as in Example 1 described above, a film-like adhesive for electrode connection having an anisotropic conductivity having a thickness of 35 μm was prepared, and a joined body of a flexible printed wiring board and a glass substrate was obtained. Then, the above results of performing temporary adhesion evaluation, repairability evaluation, and connection reliability evaluation under the same conditions as in Example 1 are shown in Table 1.

(Comparative Example 5)
As the conductive particles, linear nickel fine particles having a long diameter L distribution of 1 μm to 8 μm and a short diameter R distribution of 0.1 μm to 0.4 μm were used. The epoxy resin includes (1) phenoxy resin [manufactured by Japan Epoxy Resin Co., Ltd., trade name Epicoat 1256, average molecular weight 50000], and (2) bisphenol A type liquid epoxy resin [Dainippon Ink Chemical Co., Ltd.] Manufactured, trade name Epicron 850, average molecular weight 380]. In addition, as the latent curing agent, (3) microcapsule type imidazole curing agent [trade name Novacure HX3941, manufactured by Asahi Kasei Epoxy Co., Ltd., 13% by weight of bisphenol A type epoxy resin with an average molecular weight of 380, average molecular weight of 350 Containing 52 wt% of bisphenol F type epoxy resin]. Further, (4) spherical silica particles having an average particle diameter of 20 nm are used as the inorganic filler, and these (1) to (4) are (1) 40 / (2) 55 / (3) 20 / ( 4) Blended at a ratio of 5. In addition, the compounding quantity of the epoxy resin whose average molecular weight is less than 500 is 56.7 weight%. Next, in the same manner as in Example 1 described above, a film-like adhesive for electrode connection having an anisotropic conductivity having a thickness of 35 μm was prepared, and a joined body of a flexible printed wiring board and a glass substrate was obtained. Then, the above results of performing temporary adhesion evaluation, repairability evaluation, and connection reliability evaluation under the same conditions as in Example 1 are shown in Table 1.

As shown in Table 1, in Examples 1-5 , it turns out that temporary adhesiveness is favorable in any case. Further, it can be seen that the initial connection resistance is 1Ω or less and the repairability is good. Further, it can be seen that the number of times of wiping off the adhesive remaining on the copper electrode of the glass substrate is 50 times or less, and the working time for repairing is short. Furthermore, it can be seen that the connection resistance after 500 hours is 3Ω or less, and the connection reliability is good.

On the other hand, as shown in Table 1, in Comparative Example 1, the amount of the epoxy resin having an average molecular weight of less than 500 with respect to the adhesive component is less than 20% by weight (16.4% by weight). It turns out that the sex has fallen. In Comparative Example 2, since the blending amount of the epoxy resin having an average molecular weight of 500 or more and 4000 or less with respect to the adhesive component is larger than 40% by weight (45.2% by weight), the connection resistance after 500 hours This value is 3Ω or more, and it can be seen that the connection reliability between the electrodes is lowered.

  Moreover, as shown in Table 1, in any of Comparative Examples 1 to 5, the initial connection resistance is less than 1Ω in any case, but the number of times of wiping off the adhesive remaining on the copper electrode of the glass substrate is 50. It is larger than the number of times and it can be seen that the work time for repairing is long. This is because Comparative Examples 1 to 5 contain no polyvinyl butyral resin in any case, and Comparative Examples 4 and 5 contain only an epoxy resin having an average molecular weight of less than 500. In addition, since an epoxy resin having an average molecular weight of 500 or more and 4000 or less is not contained, the crosslinking density of the entire epoxy resin is considered to be excessively high.

  As an application example of the present invention, there can be mentioned an electrode connecting adhesive for bonding and electrically connecting a wiring board or an electronic component provided with electrodes, circuits and the like.

It is sectional drawing which shows the wiring board which mounted the flexible printed wiring board with the adhesive agent for electrode connection which concerns on this embodiment. As an electrode connecting adhesive according to an embodiment of the present invention, an anisotropic conductive adhesive containing conductive particles is used, and a flexible printed wiring board is mounted on a wiring board via the anisotropic conductive adhesive. It is sectional drawing which shows a state. It is a figure for demonstrating the electroconductive particle used in the adhesive agent for electrode connection which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Wiring board, 2 ... Electrode connection adhesive, 3 ... Flexible printed wiring board, 4 ... Wiring electrode (ITO electrode), 5 ... Metal electrode (copper electrode), 6 ... Conductive particle, L ... Conductive particle Long diameter, R ... minor diameter of conductive particles, X ... thickness direction of electrode connecting adhesive having film shape, Y ... surface direction of electrode connecting adhesive having film shape

Claims (5)

In the electrode connecting adhesive containing a d epoxy resin and conductive particles and the latent curing agent,
Adhesive for the electrode connections, as well as containing polyvinyl butyral resin as the epoxy resin, the average molecular weight of the thermosetting below 500 epoxy resin, the average molecular weight of 500 to 4,000 of thermosetting epoxy resin , Containing phenoxy resin ,
Said phenoxy resin, said epoxy resin having an average molecular weight of less than 500, and the average molecular weight of 500 to 4,000 epoxy resin, the polyvinyl butyral resin and the latent curing agent, when the adhesive component,
The amount of the epoxy resin below the average molecular weight against the adhesive component 500, a 20% by weight to 50% by weight, average molecular weight against the adhesive component of 500 to 4,000 The amount of the epoxy resin is 15 wt% or more and 40 wt% or less,
The compounding amount of the polyvinyl butyral resin with respect to the adhesive component is 1% by weight or more and 8.7 % by weight or less . 2. The electrode connecting adhesive according to claim 1 , wherein the conductive particles are metal powder having a shape in which a large number of fine metal particles are connected in a straight chain or a needle shape. The adhesive for electrode connection according to claim 2 , wherein the conductive particles have an aspect ratio of 5 or more. It has a film shape, The adhesive agent for electrode connection as described in any one of Claim 1 thru | or 3 characterized by the above-mentioned. The adhesive for electrode connection according to claim 4 , wherein a major axis direction of the conductive particles is oriented in a thickness direction of the adhesive having the film shape.

Images