JP2020193309A - Conductive adhesive and method for using conductive adhesive - Google Patents

Abstract

To provide: a conductive adhesive including micro phase separation, where conductive particles tend to be unevenly distributed more in a base resin than in a region formed by in-situ polymerization; and a method for using a conductive adhesive by using the same.SOLUTION: Provided is a conductive adhesive comprising a base resin and a region formed by in-situ polymerization, which are micro-phase separated. The conductive adhesive contains conductive particles and, when a content of the conductive particles contained in the base resin is denoted by φ1 (wt.%) and a content of the conductive particles contained in the is-situ polymerized region is denoted by φ2 (wt.%), a relationship, φ1>φ2, is satisfied.SELECTED DRAWING: Figure 1

Description

The present invention relates to a conductive adhesive and a method of using the conductive adhesive.
In particular, in a conductive adhesive that is microphase-separated after curing, conductive particles are more likely to be unevenly distributed in the base resin than in a region formed by In-Situ polymerization (sometimes referred to as in-situ polymerization). The present invention relates to a conductive adhesive and a method of using the conductive adhesive using the conductive adhesive.

Conventionally, various conductive adhesives containing a predetermined amount of conductive particles in an electrically insulating resin have been proposed.
For example, a conductive adhesive having both good adhesiveness and reworkability and having good low-temperature connectivity and the like has been proposed (see, for example, Patent Document 1).
More specifically, it is a conductive adhesive containing a conductive filler and an organic binder composed of a thermoplastic resin and a thermosetting resin, and the metal particles of the conductive filler are formed into a plurality of constituent metals. The low melting point layer on the surface of the metal particles, which does not contain lead and the concentration of the constituent metals changes continuously between the surface of the metal particles and the inside of the metal particles and melts near the curing temperature of the organic binder, and the height inside the metal particles. It is a conductive adhesive characterized by having a melting point layer.

Further, a conductive adhesive which controls sufficient conductivity and excellent coating workability has also been proposed (see, for example, Patent Document 2).
More specifically, when an epoxy resin or the like as a thermosetting resin, a polyether sulfone resin or the like as a thermoplastic resin, and a conductive adhesive containing conductive particles are cured. In addition, it is a conductive adhesive in which a thermosetting resin and a thermoplastic resin are phase-separated and conductive particles are unevenly distributed.
The shape of the conductive particles is preferably spherical, agglutinating, flat plate, needle-shaped, or rod-shaped, and the average particle size thereof is in the range of 0.01 to 20 μm.
Therefore, as shown in line A of FIG. 7, in the case of a conductive adhesive containing an epoxy resin or the like as a thermosetting resin, a polyether sulfone resin or the like as a thermoplastic resin, and conductive particles, the line Compared with the case of the conductive adhesive not containing the polyether sulfone resin shown in B, the conductivity was good.

JP 2001-172606 (Claims, etc.) JP 2013-67755 (Claims, etc.)

However, in the conductive adhesive disclosed in Patent Document 1, the concentration of the constituent metal changes continuously between the surface of the metal particle and the inside of the metal particle, whereby a special low melting point layer and a high melting point layer are provided. It is necessary to use a conductive filler, and there is a problem that the manufacturing cost of the conductive adhesive tends to be high.
In addition, there is a problem that the amount of conductive particles to be blended in order to obtain a predetermined conductivity becomes a considerable amount.
In addition, a phenoxy resin or the like is used as the thermoplastic resin, and an epoxy resin or the like is used as the thermosetting resin, and since a resin having good compatibility with each other is used, microphase separation does not occur. , There was no intention to unevenly distribute the conductive particles.

Further, in the conductive adhesive disclosed in Patent Document 2, when the thermosetting resin is thermally cured, the thermosetting resin and the thermoplastic resin are microphase-separated, but the size of the phase other than the unevenly distributed phase of the conductive particles is large. There is a problem that the width must be as small as several nm to 20 nm, and the uneven distribution of the conductive particles is still poor even in the uneven distribution phase of the conductive particles.

Therefore, as a result of diligent studies, the present inventors conducted phase separation (micro phase separation) between the base resin and the region formed by In-Situ polymerization by performing In-Situ polymerization in the base resin under predetermined conditions. ), It was found that more conductive particles were unevenly distributed in the base resin, and the present invention was completed.
That is, the present invention utilizes In-Situ polymerization, and even if a relatively small amount of conductive particles are blended, the conductive particles are unevenly distributed in the base resin in a relatively large amount, resulting in good conductivity. It is an object of the present invention to provide a conductive adhesive having a above-mentioned property, and a method of using the conductive adhesive for easily obtaining such good conductivity.

According to the present invention, the base resin and the region formed by In-Situ polymerization are microphase-separated conductive adhesives, wherein the conductive adhesive contains conductive particles and is a base. When the content of the conductive particles contained in the resin is φ1 (% by weight) and the content of the conductive particles contained in the region formed by In-Situ polymerization is φ2 (% by weight), φ1> φ2. A conductive adhesive characterized by satisfying the relationship is provided, which can solve the above-mentioned problems.
That is, it is possible to obtain a conductive adhesive in which the base resin and the region formed by In-Situ polymerization are phase-separated (micro-phase separation) and the conductive particles contained in the base resin are unevenly distributed. Can be done.
Therefore, even if a relatively small amount of conductive particles are blended, it is unevenly distributed in a relatively large amount with respect to the base resin as compared with the region formed by In-Situ polymerization, so that good conductivity can be obtained. it can.

The conductive adhesives of the following aspects can be obtained by heat treatment (first heat treatment and second heat treatment), and these are also basically included in the conductive adhesive of the present invention. To do.
Type A: Conductive adhesive before first heat treatment / before second heat treatment (usually liquid)
Type B: Conductive adhesive after the first heat treatment / before the second heat treatment (usually liquid)
Type C: Conductive adhesive after first heat treatment / second heat treatment (usually solid)

Further, in constructing the conductive adhesive of the present invention, when the reaction temperature of the In-Situ polymerization is T1 (° C.) and the reaction temperature of the base resin is T2 (° C.), ΔT (= T2-T1). It is preferable that the absolute value of is in the range of 5 to 50.
By satisfying such a temperature relationship, even when an acrylic monomer or the like inserted in a relatively low-viscosity base resin before thermosetting or the like is contained, In-Situ polymerization can be used. By polymerizing uniformly and accurately, the base resin and the region formed by In-Situ polymerization can be microphase-separated.

Further, in constructing the conductive adhesive of the present invention, it is preferable that the base resin is a thermosetting epoxy resin.
As described above, if the base resin region is a thermosetting epoxy resin, the reaction temperature T2 (° C.) can be adjusted relatively easily, and ΔT (T2-T1) can be set to a value within a predetermined range. Can easily and accurately perform microphase separation between the base resin region and the region formed by In-Situ polymerization.

Further, in constructing the conductive adhesive of the present invention, the region formed by In-Situ polymerization is derived from a combination of an acrylic monomer and a radical generator, or a combination of a blocked isocyanate compound and an active hydrogen group-containing compound. Is preferable.
If the region formed by In-Situ polymerization is derived from a combination of an acrylic monomer and a radical generator, the base resin and the region formed by In-Situ polymerization can be more easily provided. Microphase separation can be performed with high accuracy.

Further, in constructing the conductive adhesive of the present invention, it is preferable that the content of the conductive particles is in the range of 25 to 70% by weight with respect to the total amount.
By limiting the content of the conductive particles in this way, even if a relatively small amount of the conductive particles is blended, good conductivity can be obtained by unevenly distributing the conductive particles with respect to the base resin.
On the other hand, in applications that require even lower conductivity, for example, electric bonding members of power semiconductors, it is necessary to provide a conductive adhesive that generates less heat and cracks by blending a considerable amount of conductive particles. Can be done.

Further, in constructing the conductive adhesive of the present invention, the viscosity was set to 0.1 to 300 Pa · sec. It is preferable that the value is within the range of (measurement temperature: 25 ° C.).
With such a viscosity of the conductive adhesive, it can be accurately applied to a predetermined place by using a dispenser or the like as a liquid conductive adhesive, and also for the problem of sedimentation of conductive particles and the like. It can be easily controlled.

In constituting the conductive adhesive of the present invention, it is preferable that the specific resistance within a range of ^{1 × 10 -4 ~1 × 10 0} Ω · cm.
By limiting the specific resistance (conductivity) of the conductive adhesive in this way, it is expected that the conductive adhesive will be used in a wide range of applications, such as a bonding member of a power semiconductor, as a countermeasure against electrostatic shielding.

Another aspect of the present invention is a method of using a conductive adhesive in which the base resin and the region formed by In-Situ polymerization are microphase-separated, and the following steps (1) to (1) to ( 4) is a method of using a conductive adhesive, which comprises.
(1) A step of preparing a conductive adhesive containing conductive particles and having a microphase separation between the base resin and the region formed by In-Situ polymerization (2) Applying the conductive adhesive to the object to be adhered. Steps to apply (3) Heat treatment (first heat treatment) of the conductive adhesive to form a region formed by In-Situ polymerization (4) In-Situ polymerization with the base resin The region is micro-phase separated, the content of the conductive particles contained in the base resin is φ1 (% by weight), and the content of the conductive particles contained in the region formed by In-Situ polymerization is φ2. A step of satisfying the relationship of φ1> φ2 when (% by weight) is set. That is, by carrying out in this way, the region of the base resin and the region formed by In-Situ polymerization can be phase-separated with high accuracy. It is possible to efficiently obtain a conductive adhesive which is (micro-phase separated) and has many conductive particles unevenly distributed in the base resin.
Therefore, as a method of using the conductive adhesive, even if a relatively small amount of conductive particles are blended, the base resin is more unevenly distributed, so that good conductivity can be obtained.

FIG. 1 shows the relationship between the amount of silver added (% by weight) in the conductive adhesive obtained by using In-Situ polymerization and the specific resistance (Ω · cm) of the conductive adhesive, and the In-Situ polymerization. It is a figure provided for demonstrating the relationship between the addition of silver (% by weight) in an unused conductive adhesive, and the specific resistance (Ω · cm) of the conductive adhesive. 2 (a) to 2 (c) are diagrams provided for explaining the microphase separation including the base resin of the present invention and the region by In-Situ polymerization. FIG. 3 is a diagram provided for explaining the relationship between the reaction temperature of the conductive adhesive (conductive particles / thermosetting epoxy / acrylic resin by In-Situ polymerization) of the present invention and the viscosity. FIG. 4 is a diagram provided for explaining the relationship between the reaction temperature of the conventional conductive adhesive (conductive particles / thermosetting epoxy / polyether sulfone resin) and the viscosity. FIG. 5A is a diagram (photograph, magnification 2000) provided for explaining the state of the conductive particles in the phase-separated conductive adhesive, and FIG. 5B is a non-phase-separated conductive film. It is a figure (photo, magnification 2000) provided for explaining the silver state in a sex adhesive. FIG. 6 is a diagram (photograph, magnification 1000) provided for explaining the surface state when the phase-separated conductive adhesive is formed into a sheet. FIG. 7 shows the relationship (line A) between the amount of silver added (vol.%) In the conductive adhesive containing polyether sulfone (PES) and the conductivity (S / cm) of the conductive adhesive, and In order to explain the relationship (line B) between the amount of silver added (vol.%) In the conductive adhesive containing no polyether sulfone (PES) and the conductivity (S / cm) of the conductive adhesive, respectively. It is a figure to serve.

[First Embodiment]
The first embodiment is a conductive adhesive in which the base resin and the region formed by In-Situ polymerization are microphase-separated, and the conductive adhesive contains conductive particles. When the content of the conductive particles contained in the base resin is φ1 (% by weight) and the content of the conductive particles contained in the region formed by In-Situ polymerization is φ2 (% by weight), φ1> φ2. It is a conductive adhesive characterized by satisfying the relationship of.
Hereinafter, the conductive adhesive of the first embodiment will be specifically described separately for each constituent requirement.

1. 1. Conductive particles (1) Average particle size The average particle size (volume average particle size) of the conductive particles is not particularly limited, but is usually preferably a value within the range of 0.1 to 30 μm.
The reason for this is that if the average particle size of the conductive particles is less than 0.1 μm, they may easily aggregate and the handleability may be excessively lowered.
On the other hand, if the average particle size of the conductive particles exceeds 30 μm, it may be difficult to unevenly distribute the conductive particles in the thermosetting resin after thermosetting and microphase separation. Because there is.
Therefore, the average particle size of the conductive particles is more preferably set to a value in the range of 0.5 to 15 μm, and further preferably set to a value in the range of 1.5 to 5 μm.
The average particle size of the conductive particles can be measured by a laser diffraction / scattering method particle size distribution measuring device in accordance with JIS Z 8819-2: 2001, or can be measured from an electron micrograph. Further, it can be calculated from the electron micrograph using an image processing device.

(2) Morphology The morphology of the conductive particles is also not particularly limited, but is usually spherical, elliptical spherical, cubic, rod-shaped, barbed, flaky, irregularly shaped, or a combination thereof. Is preferable.
In particular, when the morphology of the conductive particles is a chestnut shape or a flaky shape, it is easy to unevenly distribute the conductive particles in the thermosetting resin after heat curing and microphase separation, which is a more preferable form. Is.

Further, regarding the form of the conductive particles, it is more preferable that the solid silver particles have a core material for crystal growth inside.
The reason for this is that by using such solid silver particles, it is possible to adjust the crystal change characteristics (long-term shape retention of silver particles) of silver particles even if they are in the shape of a chestnut, and by extension, conductivity. This is because the bulk density of the adhesive can be easily adjusted.

Further, regarding the form of the conductive particles, it is more preferable that the hollow silver particles have predetermined voids inside.
The reason for this is that by using such hollow silver particles, the uneven distribution of silver particles in the conductive adhesive can be controlled more easily, and the weight and cost of the conductive adhesive can be reduced. This is because it can contribute to.

(3) Bulk Density The bulk density of the conductive particles is preferably set to a value within the range of 0.5 to 5 g / cm ³ .
The reason for this is that if the bulk density of the conductive particles is less than 0.5 g / cm ³ , the adhesive strength of the conductive adhesive may decrease.
On the other hand, if the bulk density of the conductive particles exceeds 5 g / cm ³ , it may be difficult to unevenly distribute the thermosetting resin after the microphase separation.
Therefore, it is more preferable to set the bulk density of the conductive particles within a range of 1 to 4 g / cm ^3, still more preferably a value within the range of 1.5~3g / cm ^3.
The bulk density of the conductive particles can be measured according to the tap method of JIS K5101.

(4) Blending amount The blending amount of the conductive particles is preferably a value within the range of 25 to 70% by weight with respect to the total amount of the conductive adhesive.
The reason for this is that good conductivity can be obtained by uniformly and clearly unevenly distributing each of the mixture of a relatively small amount of conductive particles and a relatively large amount of conductive particles. Because it can be done.
Therefore, it is more preferable that the blending amount of the conductive particles is in the range of 30 to 60% by weight with respect to the total amount of the conductive adhesive, and the value is in the range of 35 to 50% by weight. Is even more preferable.

(5) Surface coating layer Further, it is preferable to have a surface treatment layer containing at least one of an organic acid, an organic acid salt, a surfactant, and a coupling agent as a main component on the surface of the conductive particles.
The reason for this is that by having such a surface-treated layer, it is possible to adjust the crystal change characteristics of the conductive particles (for example, the long-term shape retention of silver particles).
If the main component constituting the surface treatment layer is an organic acid or an organic acid salt, the affinity for the thermosetting resin is adjusted, and the conductivity in the thermosetting resin after microphase separation by the thermosetting treatment is performed. There is also an advantage that uneven distribution of sex particles becomes easier.

(5) -1 type The type of such an organic surface treatment agent is not particularly limited, but is usually hexanoic acid, 2-ethylhexanoic acid, octanoic acid, decanoic acid, lauric acid, and myristin. Acids, palmitic acid, stearic acid, bechenic acid, montanic acid, oleic acid, linoleic acid, linolenic acid, 12-hydroxystearic acid, benzoic acid, gluconic acid, cinnamon acid, salicylic acid, gallic acid, pentadecanoic acid, heptadecanoic acid, arakin One of acids, lignoseric acid, serotic acid, 2-pentylnonanoic acid, 2-hexyldecanoic acid, 2-heptyldodecanoic acid, isostearic acid, palmitreic acid, isooleic acid, ellaic acid, ricinolic acid, gadrenic acid, erucic acid, serachoreic acid, etc. Basic acid: One type alone or a combination of two or more types such as dibasic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelli acid, suberic acid, azelaic acid, malic acid, phthalic acid and fumaric acid. Can be done.

(5) -2 Blending amount The blending amount of the organic surface treatment agent is preferably a value within the range of 0.1 to 8 parts by weight with respect to 100 parts by weight of the conductive particles (silver particles, etc.). ..
The reason for this is that by adjusting the blending amount of the organic surface treatment agent in this way, the crystal change characteristics of the conductive particles can be adjusted, and by extension, the uneven distribution of the conductive particles in the conductive adhesive can be further facilitated. This is because it can be controlled.
That is, when the blending amount of the organic surface treatment agent is less than 0.1 parts by weight, the conductive particles may easily aggregate with each other. On the other hand, if the blending amount of the organic surface treatment agent exceeds 8 parts by weight, good uneven distribution of the conductive particles may not be obtained.
Therefore, it is more preferable that the blending amount of the organic surface treatment agent is in the range of 0.5 to 7 parts by weight with respect to 100 parts by weight of the conductive particles, and the value is in the range of 1 to 6 parts by weight. Is more preferable.

2. 2. Base Resin In constructing the conductive adhesive of the present invention, it is preferable to use a thermosetting resin, a thermoplastic resin, or one of the resins as the base resin.
Then, by the first heat treatment, In-Situ polymerization of a predetermined monomer component is carried out in the base resin to form a predetermined region (thermosetting region and / or thermoplastic region), and then a second heat treatment is performed. Therefore, the function as a predetermined conductive adhesive can be exhibited.
In that case, when the conductive adhesive is finally heat-cured or the like, it is preferable to blend a region obtained by In-Situ polymerization with a base resin that is microphase-separated from each other.
The reason for this is that by blending the region formed by In-Situ polymerization as a base resin that is phase-separated from each other, even if a relatively small amount of conductive particles are blended, it is basically relative to the base resin. This is because the conductive particles can be concentrated and unevenly distributed, and for example, good specific resistance (conductivity) as shown in line A of FIG. 1 can be obtained.
However, by appropriately controlling the type of the base resin, the type of the region formed by In-Situ polymerization, the surface treatment agent and the surface treatment of the conductive particles, etc., the In-Situ polymerization can be performed more than the base resin. It has also been separately found that the conductive particles can be concentrated and unevenly distributed in the region.

Here, in FIG. 1, line A corresponds to a conductive adhesive utilizing a phase-separated state based on In-Situ polymerization of the present invention, and line B is a conventional conductive adhesive in a non-phase-separated state. Therefore, it corresponds to a conductive adhesive that does not utilize In-Situ polymerization.
Then, as shown by line A, at the same amount of silver added (for example, in the range of 40% by weight to 60% by weight) as compared with line B, conductive adhesion utilizing a phase-separated state based on In-Situ polymerization. It is understood that the agent has a specific resistance value that is about three orders of magnitude lower.

(1) Type 1
The type of resin used for the base resin is not particularly limited, but for example, as the thermosetting resin, an epoxy resin (including a curing agent), a phenol resin, a polyimide resin, and an acrylic resin ( Cross-linked acrylic resin), urethane resin (cross-linked urethane resin), silicone resin, unsaturated polyester resin, vinyl ester resin, melamine resin, urea resin, etc., or a combination of two or more. Be done.
Among these, it can be said that an epoxy resin containing a curing agent is more preferable as the resin used for the base resin.
The reason for this is that by using an epoxy resin containing such a curing agent, it is easy to control the mutual polarity with the region formed by In-Situ polymerization, and by extension, phase separation easily occurs in the base resin. This is because the uneven distribution of the conductive particles in the above becomes easier.
Further, if the base resin is an epoxy resin, it exhibits good adhesiveness to various adherends as a conductive adhesive, and further, it can obtain appropriate mechanical strength.

(2) Type 2
On the other hand, examples of the thermoplastic resin used for the base resin include phenoxy resin, acrylic resin (non-crosslinked acrylic resin), urethane resin (non-crosslinked urethane resin), and polyester resin (non-crosslinked polyester resin). , Silicone-based resin, etc., may be used alone or in combination of two or more.
Of these, the non-crosslinked urethane resin is a thermoplastic resin as a more preferable base resin.
The reason for this is that by using the thermoplastic resin contained in such a base resin, it is easy to control the mutual polarity with the thermoplastic resin formed by In-Situ polymerization, and by extension, phase separation easily occurs. This is because the uneven distribution of the conductive particles in the thermoplastic resin of the base resin becomes easier.
Further, if the base resin is a thermoplastic non-crosslinked urethane resin, it is suitable as a conductive adhesive because it has relatively excellent repeatability and an appropriate hardness.

(3) Blending amount The blending amount of the base resin is preferably a value within the range of 15 to 225 parts by weight with respect to 100 parts by weight of the conductive particles (silver particles or the like).
The reason for this is that by adjusting the blending amount of the base resin in this way, uneven distribution of the conductive particles in the thermosetting region and / or the thermoplastic resin of the base resin becomes easier, and good electrical characteristics are obtained. This is because the adhesiveness to various adherends is further improved.
That is, if the blending amount of the base resin is less than 15 parts by weight, the microphases may not be stably separated after the heat treatment, and the uneven distribution of the conductive particles may be insufficient.
On the other hand, if the blending amount of the base resin exceeds 225 parts by weight, the conductivity may decrease, and conversely, the specific resistance may increase excessively.
Therefore, it is more preferable that the blending amount of the base resin is in the range of 17 to 210 parts by weight with respect to 100 parts by weight of the conductive particles, and the value is preferably in the range of 21 to 195 parts by weight. More preferred.

3. 3. In-Situ Polymerization Ingredients (1) Types As the types of In-Situ polymerization components, a monoma component or a compound that can be mixed in a predetermined amount in a base resin and cause a predetermined polymerization reaction on the spot. If there is, the present invention is not particularly limited, but for example, a combination of an acrylic monoma and a radical generator, a combination of a blocked isocyanate compound and an active hydrogen group-containing compound (for example, a combination of a blocked product of a urethane prepolymer and a polyamine). It is preferably at least one of an epoxy resin and an ion polymerization catalyst.
In particular, if the In-Situ polymerization component is a combination of an acrylic monoma and a radical generator, or a combination of a blocked isocyanate compound and an active hydrogen group-containing compound, even in various base resins, the temperature is relatively low. It can be said that it is preferable because In-Situ polymerization is carried out rapidly and uniformly.

(2) Blending amount The blending amount of the component for In-Situ polymerization is preferably a value in the range of 30 to 200 parts by weight with respect to 100 parts by weight of the base resin.
The reason for this is that if the blending amount of the component for in-situ polymerization is excessively small, less than 30 parts by weight, it is difficult to carry out in-situ polymerization rapidly and uniformly at a relatively low temperature in various base resins. This is because it may become.
On the other hand, if the blending amount of the component for In-Situ polymerization exceeds 200 parts by weight, on the contrary, unreacted In-Situ polymerization may easily remain.
Therefore, it is more preferable that the blending amount of the component for in-situ polymerization is in the range of 40 to 150 parts by weight with respect to 100 parts by weight of the base resin, and the value is in the range of 50 to 100 parts by weight. It is more preferable to do so.

4. Other compounding components (1) Viscosity adjuster In addition, as a viscosity adjuster (diluent, phase separation adjuster, etc.) in the conductive adhesive, aromatic hydrocarbons, esters, ketones, glycol ethers, etc. It is preferable to blend at least one kind.
More preferably, the types of aromatic hydrocarbons are toluene, xylene and the like, the esters are ethyl acetate, amyl acetate and the like, and the ketones are methyl ethyl ketone, methyl isobutyl ketone and the like, and glycols. Examples of the ether include ethylene glycol monobutyl ether and ethylene glycol dimethyl ether.

The blending amount of the viscosity adjusting agent in the conductive adhesive is determined by the use of the conductive adhesive and the like, but is usually a value within the range of 0.1 to 2000 parts by weight with respect to 100 parts by weight of the base resin. Is preferable.
The reason for this is that if the blending amount of the viscosity modifier is excessively small, less than 0.1 parts by weight, the effect of adding the blending may not appear, and conversely, the blending amount of the viscosity modifier is 2000. If it exceeds a part by weight, In-Situ polymerization may not be properly carried out.
Therefore, the blending amount of the viscosity modifier is more preferably set to a value in the range of 1 to 200 parts by weight, and set to a value in the range of 10 to 100 parts by weight with respect to 100 parts by weight of the base resin. More preferred.

(2) Silica particles It is also preferable to add silica particles as an inorganic filler to the conductive adhesive.
The reason for this is that the presence of silica particles in the conductive adhesive makes it easier to adjust the polarity between the base resin and the region formed by In-Situ polymerization, and further facilitates phase separation. Is.
Further, the presence of silica particles in the conductive adhesive improves the thermal conductivity, durability, and adhesiveness.

Here, as the silica particles, either hydrophobic silica or hydrophilic silica can be suitably blended.
Further, it may be agglomerated silica particles or non-aggregated silica particles.
The amount of the silica particles added is preferably in the range of 0.1 to 5% by weight with respect to the total amount.
The reason for this is that if the amount of the silica particles added is less than 0.1% by weight, the addition effect may not be exhibited.
On the other hand, if the amount of the silica particles added exceeds 5% by weight, the electrical conductivity and the thermal conductivity may be excessively lowered.
Therefore, the amount of such silica particles added is more preferably set to a value in the range of 0.2 to 3% by weight, and set to a value in the range of 0.5 to 2% by weight with respect to the total amount. Is even more preferable.

(3) Other Additives In addition, various other additives such as antioxidants, ultraviolet absorbers, metal ion trappers, viscosity modifiers, inorganic fillers other than silica particles, and organic fillers are contained in the conductive adhesive. , Carbon fiber, colorant, coupling agent and the like are also preferable.
In that case, although it depends on the type of additive to be blended and the purpose of blending, it is usually preferably in the range of 0.01 to 10% by weight, 0.1 to 10% by weight, based on the total amount of the conductive adhesive. More preferably, it is in the range of ~ 5% by weight.
In addition, since the oxidative deterioration of the conductive adhesive may be accelerated due to the addition of conductive particles, as an antioxidant, an amine-based antioxidant, a phenol-based antioxidant, or a phosphoric acid may be used. It is preferable to add an ester-based antioxidant or the like in the range of 0.1 to 10% by weight based on the total amount.

5. Viscosity The viscosity of the conductive adhesive (measurement temperature: 25 ° C., the same applies hereinafter) can be appropriately changed depending on the application and the like, but is usually 0.1 to 300 Pa · sec. It is preferable that the value is within the range of.
The reason for this is that if the viscosity of the conductive adhesive is less than 0.1 Pa · sec, the conductive particles may easily settle, or the electrical conductivity and thermal conductivity may be significantly reduced. Because.
On the other hand, if the viscosity of the conductive adhesive exceeds 300 Pa · sec, it may be difficult to handle it, or even if a dispenser is used, it may be difficult to apply it uniformly.
Therefore, the viscosity of the conductive adhesive is more preferably set to a value in the range of 1 to 150 Pa · sec, and further preferably set to a value in the range of 5 to 40 Pa · sec.
The viscosity of the conductive adhesive can be measured under predetermined conditions using the E-type viscometer of Example 1 described later.

6. Density In addition, the density of the conductive adhesive is usually preferably set to a value in the range of 1.3 to 3.5 g / cm ³ .
The reason for this is that if the density of the conductive adhesive is less than 1.3 g / cm ³ , the electrical conductivity and the thermal conductivity may be significantly reduced.
On the other hand, when the density of the conductive adhesive exceeds 3.5 g / cm ³ , the conductive particles are unevenly distributed even if the base resin and the region formed by In-Situ polymerization are phase-separated. This is because it may be difficult.
Further, if the density of the conductive adhesive exceeds 3.5 g / cm ³ , the handleability may be lowered, or the adhesiveness may be lowered, so that the adhesive may be easily peeled off from the object to be adhered. is there.
Therefore, the density of the conductive adhesive, it is more preferably set to a value within the range of 1.5~3g / cm ^3, further to a value within the range of 1.6~2.5g / cm ³ preferable.

7. Manufacturing Method Hereinafter, with reference to FIGS. 2 (a) to 2 (c) and FIGS. 3 to 4, the conductive particles 10, the monoma component 12 for In-Situ polymerization, the monoma component 14 for the base resin, and the like are conductive. A method for producing the sex adhesive 20 will be described.

(1) Preparation of Undiluted Solution of Conductive Adhesive As shown in FIG. 2A, the conductive adhesive is composed of conductive particles 10, a monoma component 12 for In-Situ polymerization, a monoma component 14 for a base resin, and the like. 20 undiluted solutions are produced.
For example, using a propeller mixer, a planetary mixer, a triple roll, a kneader, a spatula, etc., a predetermined amount of conductive particles 10, a monoma component 12 for in-situ polymerization, and the like are added to the monoma component 14 for the base resin. Mix and disperse to produce a uniform stock solution 20a of conductive adhesive.

(2) Pretreatment Next, although not shown, it is preferable to remove the obtained stock solution of the conductive adhesive by filtering out agglomerates of conductive particles, dust and the like using a filter or the like.
The reason for this is that by filtering the agglomerates of the conductive particles or the like, it is possible to effectively prevent clogging when the conductive adhesive is applied using a dispenser or the like.
It should be noted that conductive particles (silver particles, etc.) have cavities inside and are subjected to a predetermined surface treatment, so that agglomerates are less likely to be generated. For example, a mesh filter having a mesh size of 20 to 200 μm. There is an advantage that it can be easily filtered by using or the like.

(3) In-Situ Polymerization Then, as shown in FIG. 2B, In-Situ polymerization in the monomer component 14 for the base resin by heat treatment or the like (sometimes referred to as first heat treatment or the like). Monomer component 12 for In-Situ polymerization.
That is, in the monomer component 14 for the base resin, the monoma component 12 is In-Situ polymerized to form a predetermined region 12a, which is phase-separated from the monoma component 14 for the base resin, and the conductive particles 10 are formed accordingly. Can be 20b of a conductive adhesive before phase separation (sometimes referred to as a conductive adhesive after In-Situ polymerization) in which is slightly unevenly distributed.

As shown in FIG. 3, when the first heat treatment or the like is performed, an acrylic monomer is used as a monomer component for In-Situ polymerization, so that the In-Situ polymerization is basically an acrylic radical. It can be said that it is polymerization.
Then, by the heat treatment, the In-Situ polymerization proceeds, and the viscosity of the conductive adhesive before the phase separation increases again, for example, at 60 to 80 ° C.
In the case of the conductive adhesive of the present invention shown in FIG. 3, for example, the viscosity at 50 to 70 ° C. is 1 × 10 ^-1 Pa · sec. It is understood that the value is fairly low.

On the other hand, in the case of the conductive adhesive which does not utilize the conventional In-Situ polymerization shown in FIG. 4, for example, at 50 to 70 ° C., 1 × 10 ² Pa · sec. It is a value with a fairly high viscosity.
Therefore, the conductive adhesive of the present invention is superior in handleability and considerably superior to the conventional conductive adhesive in that the viscosity is low and the viscosity value is stable. It is understood that there is.
In the case of the conductive adhesive of the present invention, as shown in FIG. 2C, the monomer component 14 for the base resin is polymerized by heat treatment or the like (sometimes referred to as a second heat treatment or the like). The conductive adhesive 20 of the present invention can be obtained by completely phase-separating it from the region 12a formed by In-Situ polymerization, which contains a large amount of conductive particles 10.

Then, the viscosity, appearance, etc. of the obtained conductive adhesive are inspected, and the adhesive particles of the adhesiveness, conductivity, and viscosity-conducting agent are actually applied to the object to be adhered by using a dispenser or the like. It is preferable to evaluate the uneven distribution and the like to confirm that the adhesive is the conductive adhesive specified in the present invention.
For example, from the photograph of FIG. 5A, it is understood that in the conductive adhesive defined in the present invention, the conductive particles are mainly unevenly distributed in the base resin.
On the other hand, as shown in the photograph of FIG. 5B, in the case of a conductive adhesive containing only epoxy resin and not using phase separation, the conductive particles are not unevenly distributed and exist fairly uniformly as a whole. It is understood that

In the case of the conductive adhesive of the present invention, even if the phases are separated, the surface (photograph) thereof is extremely smoothed as shown in FIG.
Therefore, in the case of the conductive adhesive of the present invention, it is understood that there is no particular problem even if it is processed into a film-like form.

[Second Embodiment]
The second embodiment is a method of using a conductive adhesive in which the base resin and the region formed by In-Situ polymerization are microphase-separated, and the following steps (1) to (4) are performed. It is a method of using a conductive adhesive characterized by containing.
(1) A step of preparing a conductive adhesive containing conductive particles as the conductive adhesive and having a microphase separation between the base resin and the region formed by In-Situ polymerization (2) The conductive adhesive Steps of applying the conductive adhesive to the adherend (3) A step of heat-treating the conductive adhesive to form a region formed by In-Situ polymerization (4) A region formed by In-Situ polymerization. The base resin is formed by heat treatment to separate the microphases, and the content of the conductive particles contained in the base resin is set to φ1 (% by weight), and the content of the conductive particles contained in the region formed by In-Situ polymerization is set. A process of satisfying the relationship of φ1> φ2 when the amount is φ2 (% by weight).

1. 1. Process (1)
In step (1), a conductive adhesive containing conductive particles as the conductive adhesive and having a microphase separation between the base resin and the region formed by In-Situ polymerization when heat-treated is prepared. It is a process.
Then, in preparing the conductive adhesive, when the reaction temperature of the In-Situ polymerization is T1 (° C.) and the reaction temperature of the base resin is T2 (° C.), ΔT = absolute value (T2-T1). The value is preferably in the range of 5 to 50.
The reason for this is that by satisfying such a temperature relationship, even if it is an acrylic monomer or the like, it is uniform and uniform by In-Situ polymerization in a base resin region having a relatively low viscosity before thermosetting or the like. This is because it can be polymerized with high accuracy and microphase separated.
Therefore, it is more preferable to set ΔT = absolute value (T2-T1) to a value in the range of 10 to 45, and further to set ΔT = absolute value (T2-T1) to a value in the range of 15 to 40. preferable.
In the step (1) of preparing the conductive adhesive, the components of the conductive adhesive described in the first embodiment, the manufacturing method, and the like can be the same, so that they can be used again. The description of is omitted.

2. 2. Process (2)
Step (2) is a preparatory step for applying the conductive adhesive to the adherend using a coating device such as a dispenser to cause In-Situ polymerization. ..
Therefore, since a coating device such as a dispenser is used, it is preferable to set the viscosity of the conductive adhesive within a predetermined range.

3. 3. Process (3)
This is a step in which the conductive adhesive applied to the adherend is heat-treated (sometimes referred to as a first heat treatment) and In-Situ polymerized to form a thermoplastic region.
In that case, the heating method and heating conditions of the first heat treatment can be appropriately changed depending on the type of the monoma component to be polymerized in-situ, but as an example, 50 to 100 ° C. for 1 to 60 minutes. It is preferable to do so.

4. Process (4)
In step (4), a region formed by In-Situ polymerization and a base resin are formed by heat treatment (sometimes referred to as a second heat treatment) to separate microphases, and the conductivity contained in the base resin is formed. A step of satisfying the relationship of φ1> φ2 when the content of the sex particles is φ1 (% by weight) and the content of the conductive particles contained in the region formed by In-Situ polymerization is φ2 (% by weight). Is.
Whether or not the relationship of φ1> φ2 is satisfied can be sufficiently inferred from the SEM image (SEM photograph).
Furthermore, based on the SEM image, the contents of the conductive particles φ1 and φ2 are calculated from the areas, respectively, and based on this, predetermined conditions such as the specific gravity of the conductive particles and the resin component are added. Each can be converted into% by weight, and it can be easily confirmed that the predetermined magnitude relationship is satisfied.

Hereinafter, the conductive adhesive and the like of the present invention will be described in more detail with reference to Examples.
[Example 1]
1. 1. Production of Conductive Particles (Silver Particles) (1) Preparation of Barley Silver Powder (A-1) First, a first aqueous solution containing silver nitrate and ion-exchanged water was prepared.
That is, 4 g of silver nitrate and 24 g of ion-exchanged water were placed in a container (container A) equipped with a stirrer, and the mixture was stirred using a magnetic stirrer until it was uniformly dissolved.
Next, a second aqueous solution containing a reducing agent and ion-exchanged water was prepared.
That is, 4 g of L-ascorbic acid as a reducing agent and 24 g of ion-exchanged water are contained in a container (container B) equipped with another stirring device, and the mixture is stirred using a magnetic stirrer until it is uniformly dissolved. , L-ascorbic acid aqueous solution.

2.5 g of a nuclear material-forming liquid was added to the obtained L-ascorbic acid aqueous solution to prepare a second aqueous solution. That is, in the total amount of the liquid for producing nuclear material, 97.4% by weight of water, 0.1% by weight of gelatin and 1% by weight of silver nitrate were mixed and then dissolved by heating at 80 ° C. .. Then, after cooling to 25 ° C., 1.5% by weight of ammonia water having a concentration of 28% by weight and 1% by weight of silver nitrate were uniformly mixed and stirred at room temperature.
Next, after maintaining the temperature so that each liquid temperature becomes 25 ° C., the second aqueous solution in the container B is added to the first aqueous solution in the container A, and stirring is continued as it is to precipitate and generate a chestnut-like silver powder. It was.

Next, the precipitated silver powder was washed with ion-exchanged water, and then 1 g of an aqueous ammonium myristic acid solution (concentration: 0.5% by weight) was added to the mixed solution to perform surface treatment with an organic acid.
After that, the surface-treated sardine-like silver powder was drained by filtration, and further dried in a vacuum oven at 100 ° C. for 3 hours to obtain sardine-like silver powder (A-1, average particle size (A-1, average particle size). D50): 3 μm) was obtained.

(2) Preparation of Blocked Isocyanate Compound (c1) 94.0 g of Samprene P-663L (urethane prepolymer solution, isocyanate content 2.9%, manufactured by Sanyo Kasei Kogyo Co., Ltd.) was contained in a container equipped with a stirrer. After heating in a warm bath at 40 ° C. and raising the temperature, 6.0 g of methyl ethyl ketooxime (manufactured by Tokyo Chemical Industry Co., Ltd.) is stored and mixed for 30 minutes. After the exotherm subsided, the mixture was further mixed in a warm bath at 70 ° C. for 3 hours.
At that time, it was confirmed by an infrared spectrometer that the peak showing the 2,200 cm- ¹ isocyanate group had disappeared, and a blocked urethane solution (c1) was obtained.

(3) Preparation of conductive adhesive 23.3 g of YL-983U (bisphenol F type epoxy resin, manufactured by Mitsubishi Chemical Corporation) and ADEKA glycyrrole ED-509S (butylphenyl glycidyl ether) in a planetary mixer container. , ADEKA) and 3.5 g of Curesol C-11Z (imidazole, manufactured by Shikoku Kasei Kogyo) were stored and mixed for 15 minutes to obtain a thermosetting resin component (B-1).
Next, 15 minutes after accommodating a mixture (C-1) of 13.3 g of the blocked isocyanate compound (c1) obtained in (2) above and 2.5 g of ADEKA Hardener EH-5030S (polyamine compound, manufactured by ADEKA). Mixed.
Next, 50.0 g of the chestnut-like silver powder (A-1) was contained, and the mixture was stirred and mixed for 60 minutes until the ingredients became uniform.
Then, after passing through three rolls (roll interval 30 to 40 μm, rotation speed 20 rpm) twice, it was returned to the planetary mixer container again.
Next, after defoaming for 30 minutes under a reduced pressure condition of −0.1 MPa · G, filtration treatment was performed using a filtration device equipped with a mesh filter having an opening of 63 μm, and conductive adhesion using In-situ polymerization was performed. The drug was obtained and the following evaluation was carried out.

2. 2. Evaluation of Conductive Adhesive (1) Viscosity The viscosity (measurement temperature: 25 ° C) of the obtained conductive adhesive (conductive paste) was measured using an E-type viscometer VISCOMETER TV22 (manufactured by Toyo Sangyo Co., Ltd.). And evaluated according to the following criteria.
⊚: 40 Pa · sec. It is as follows.
〇: 40 Pa · sec. Super, 150 Pa · sec. It is as follows.
Δ: 150 Pa · sec. Super, 300 Pa · sec. It is as follows.
X: 300 Pa · sec. It's super.

(2) Phase Separability The phase separation of the obtained conductive adhesive was evaluated.
That is, the obtained conductive adhesive was applied to a glass plate having a thickness of 1 mm by 1 cm ³ with a dispenser, and then heat-treated in a breeze oven at a temperature of 120 ° C. for 1 hour to conduct conductivity. The adhesive was thermoset and further surface-polished to prepare a measurement sample.
Next, the polished surface of the measurement sample was observed by SEM, and the phase separation between the base resin and the region formed by In-Situ polymerization was evaluated according to the following criteria.
⊚: Microphase separation is observed as a co-continuous structure.
◯: Microphase separation is observed as a sea-island structure.
Δ: Microphase separation is observed as an inverted sea island structure.
X: No phase separation is observed.

(3) Uneven distribution of conductive particles Based on the SEM image evaluated for phase separation, the area of the conductive particles in each phase separated phase is determined, and the phase of the conductive particles is taken into consideration while considering the specific gravity and the like. It was converted into the weight ratio in each separated phase.
That is, from the abundance ratio (φ1) of the conductive particles in the converted base resin region and the abundance ratio (φ2) of the conductive particles in the region formed by In-Situ polymerization, the conductive particles were formed according to the following criteria. The uneven distribution was evaluated.
⊚: Satisfy φ1> φ2 × 10.
〇: φ1> φ2 × 5, and φ1 ≦ φ2 × 10 is satisfied.
Δ: φ1> φ2, and φ1 ≦ φ2 × 5 is satisfied.
X: φ1 ≦ φ2, or is not subject to evaluation.

(4) Specific resistance The specific resistance of the obtained conductive adhesive (the reciprocal of which is the electrical conductivity) was evaluated.
That is, the obtained conductive adhesive was printed on a glass plate having a thickness of 1 mm in a line shape having a length of 50 mm, a width of 1 mm, and a thickness of 0.1 mm using a metal mask.
Next, the conductive adhesive was heat-cured in a breeze oven at a temperature of 120 ° C. for 1 hour to prepare a measurement sample.
Next, using the 4-terminal method (measurement current: 0.1 mA), the conductivity (measurement number: 3) between two points (20 mm) of the line-shaped heat-cured conductive adhesive in the measurement sample was measured. The average value was calculated and evaluated according to the following criteria.
⊚: The average value of resistivity is 1 × 10 ⁻² Ω / cm or less.
◯: The average value of the specific resistance is 1 × 10 ^-1 Ω / cm or less, and is a value outside the above range.
△: average value of the specific resistance is not more than 1 × 10 ⁰ Ω / cm, and a value outside the above range.
X: The average value of the specific resistance exceeds 1 × 10 ¹ Ω / cm, or continuity is not confirmed.

(5) Adhesiveness The adhesiveness of the obtained conductive adhesive was evaluated.
That is, a predetermined amount of the obtained conductive adhesive was applied onto a silver-plated copper plate as one of the adherends by using a dispenser.
Next, a silver sputtered 2 mm square Si chip (Si / Ti / Ag treatment) as the other adherend was superposed at a predetermined place.
Then, it was heat-treated in a breeze oven at a temperature of 120 ° C. for 1 hour to prepare a measurement sample.
Next, the shear adhesive strength (measured number: 3) in the measurement sample was measured using a tensile tester, the average value thereof was calculated, and the evaluation was made according to the following criteria.
⊚: The average value of the adhesive strength is 20 MPa or more.
◯: The average value of the adhesive strength is a value of 10 MPa or more.
Δ: The average value of the adhesive strength is a value of 5 MPa or more.
X: The average value of the adhesive strength is less than 5 MPa.

[Example 2]
In Example 2, the amount of the chestnut-like silver powder (A-1) blended as the component A was 55.0 g, and as the component B, YL-983U was 18.6 g and ADEKA glycyrrole ED-509S was 10.9 g. , And a mixture (B-3) of Curesol C-11Z with 2.8 g, and as the C component, a mixture (C) of 10.6 g of the blocked isocyanate compound (c1) and 2.0 g of ADEKA Hardener EH-509S. A conductive adhesive using In-Situ polymerization was obtained and evaluated in the same manner as in Example 1 except that -4) was used.

[Example 3]
In Example 3, the amount of the chestnut-like silver powder (A-1) blended as the component A was 60.0 g, and as the component B, YL-983U was 16.7 g and ADEKA glycyrrole ED-509S was 9.4 g. And 2.5 g of Curesol C-11Z, a mixture (B-4) was used, and as the C component, a mixture of 9.6 g of the blocked isocyanate compound (c1) and 1.8 g of Adeka Hardener EH-509S ( A conductive adhesive using In-Situ polymerization was obtained and evaluated in the same manner as in Example 1 except that C-5) was used.

[Example 4]
In Example 4, the amount of flaky silver powder (A-2) blended as the component A was 50.0 g, and as the component B, YL-983U was 20.9 g and ADEKA glycyrole ED-509S was 11.7 g. And, a mixture (B-5) of Curesol C-11Z with 3.1 g was used, and as the C component, a mixture (C) of 12.0 g of the blocked isocyanate compound (c1) and 2.3 g of Adeka Hardener EH-509S. A conductive adhesive using In-Situ polymerization was obtained and evaluated in the same manner as in Example 1 except that -6) was used.

The flaky silver powder (A-2) was produced as follows.
First, a first aqueous solution containing silver nitrate, ion-exchanged water, an organic acid, and nitric acid was prepared.
That is, in a container (container A) equipped with a stirrer, silver nitrate 4 g, ion-exchanged water 24 g, nitric acid (concentration: 60% by weight) 0.225 g, and ammonia water (concentration: 28% by weight) 0.25 g. , And stirred using a magnetic stirrer until uniformly dissolved.
Next, a second aqueous solution containing a reducing agent and ion-exchanged water was prepared.
That is, in a container (container B) equipped with another stirring device, 4 g of L-ascorbic acid as a reducing agent, 24 g of ion-exchanged water, 0.008 g of citric acid (citric acid monohydrate), and nitric acid ( Concentration: 60% by weight) 2 g, and the mixture was stirred using a magnet stirrer until uniformly dissolved.

Then, after maintaining the temperature so that the liquid temperature becomes 25 ° C., the second aqueous solution in the container B is added to the first aqueous solution in the container A, and then stirring is continued as it is to precipitate and generate flaky silver powder. It was.
Next, the flaky silver powder precipitated and generated was washed with ion-exchanged water, and then 1 g of an aqueous ammonium myristic acid solution (0.5% by weight) was added to the mixed solution to perform surface treatment with an organic acid.
After that, the surface-treated flaky silver powder was drained by filtration, and further dried in a vacuum oven at 100 ° C. for 3 hours to obtain flaky silver powder (A-2, average particle size (A-2, average particle size). D50): 5 μm) was obtained.

[Example 5]
In Example 5, the amount of flaky silver powder (A-2) blended as the component A was 45.0 g, and as the component B, YL-983U was 23.3 g and adecaglycylol ED-509S was 12.4 g. , And 3.5 g of Curesol C-11Z, and a mixture (B-6) of 13.3 g of blocked isocyanate compound (c1) and 2.5 g of Adecahardner EH-509S as C component (C). A conductive adhesive using In-Situ polymerization was obtained and evaluated in the same manner as in Example 1 except that -7) was used.

[Example 6]
In Example 6, the amount of flaky silver powder (A-2) to be blended as the component A was 40.0 g, and as the component B, YL-983U was 25.6 g and ADEKA glycyrole ED-509S was 13.2 g. , And 3.8 g of Curesol C-11Z, a mixture (B-7) was used, and as the C component, a mixture of 14.6 g of the blocked isocyanate compound (c1) and 2.8 g of Adeka Hardener EH-509S ( A conductive adhesive using In-Situ polymerization was obtained and evaluated in the same manner as in Example 1 except that C-8) was used.

[Example 7]
In Example 7, a mixture (B-2) of 28.6 g of YL-983U and 1.4 g of Curesol C-11Z was used as the B component, and the thermosetting resin compound (C) was used as the C component. In the same manner as in Example 1, an acrylic thermosetting resin compound (C-3) obtained by the following production method was used instead of -1), and the blending amount was 20.0 g. -A conductive adhesive using Situ polymerization was obtained and evaluated.
The acrylic thermosetting resin compound (C-3) was produced as follows.
That is, 99.0 g of dicyclopentenyloxyethyl methacrylate (manufactured by SIGMA-ALDRICH) and 2,2'-azobis (2,4-dimethylvaleronitrile) (manufactured by Tokyo Chemical Industry Co., Ltd.) are placed in a container with a stirrer. ) 1.0 g and then mixed and stirred for 30 minutes until uniform to obtain an acrylic thermosetting resin compound (C-3).

[Example 8]
In Example 8, a mixture of flaky silver powder (A-2) as a component A in an amount of 50 g, YL-983U as a component B in 28.6 g, and Curesol C-11Z in 1.4 g (as a component B). In-Situ polymerization was used in the same manner as in Example 1 except that B-2) was used and the amount of the acrylic thermosetting resin compound (C-3) blended as the C component was 20.0 g. A conductive adhesive was obtained and evaluated.

[Example 9]
In Example 9, flaky silver powder (A-3) was used as the A component, and the blending amount thereof was 50 g. As the B component, 28.6 g of YL-983U and 1.4 g of Curesol C-11Z were used. In-Situ polymerization was used in the same manner as in Example 1 except that the mixture (B-2) with and the acrylic thermosetting resin compound (C-3) was added to 20.0 g as the C component. A conductive adhesive was obtained and evaluated.

The flaky silver powder (A-3) was produced as follows.
First, a first aqueous solution containing silver nitrate, ion-exchanged water, an organic acid, and nitric acid was prepared.
That is, in a container (container A) equipped with a stirrer, silver nitrate 4 g, ion-exchanged water 24 g, nitric acid (concentration: 60% by weight) 0.225 g, and ammonia water (concentration: 28% by weight) 0.25 g. , And stirred using a magnetic stirrer until uniformly dissolved.
Next, a second aqueous solution containing a reducing agent and ion-exchanged water was prepared.
That is, in a container (container B) equipped with another stirring device, 4 g of L-ascorbic acid as a reducing agent, 24 g of ion-exchanged water, 0.008 g of citric acid (citric acid monohydrate), and nitric acid ( Concentration: 60% by weight) 2 g, and the mixture was stirred using a magnet stirrer until uniformly dissolved.
Then, after maintaining the temperature so that the liquid temperature becomes 25 ° C., the second aqueous solution in the container B is added to the first aqueous solution in the container A, and then stirring is continued as it is to precipitate and generate flaky silver powder. It was.

Next, the flaky silver powder precipitated and generated was washed with ion-exchanged water, and then 1 g of an aqueous solution of DL ammonium malate (0.5% by weight) was added to the mixed solution to perform surface treatment with an organic acid.
Then, the surface-treated flaky silver powder is drained by filtration, and further dried in a vacuum oven at 100 ° C. for 3 hours to obtain flaky silver powder (A-3, average particle size (A-3, average particle size). D50): 5 μm) was obtained.

[Comparative Example 1]
In Comparative Example 1, 29.3 g of YL-983U (bisphenol F type epoxy resin, manufactured by Mitsubishi Chemical Corporation) and ADEKA glycyrrole ED-509S (butylphenyl glycidyl ether, manufactured by ADEKA) were contained in a planetary mixer container. ) And 4.5 g of Curesol C-11Z (imidazole, manufactured by Shikoku Kasei Kogyo), and then mixed for 15 minutes to obtain a thermosetting resin component (B-8).
Next, 60.0 g of conductor-like silver powder (A-1) was contained, and the mixture was stirred and mixed for 60 minutes until the components of the conductive paste became uniform.
Then, after passing through three rolls (roll interval 30 to 40 μm, rotation speed 20 rpm) twice, it was returned to the planetary mixer container again.
Then, after defoaming for 30 minutes under a reduced pressure condition of −0.1 MPa · G, filtration treatment was performed using a filtration device equipped with a mesh filter having an opening of 63 μm, and conductive adhesion without using In-situ polymerization was performed. Agents were obtained and evaluated in the same manner as in Example 1.

[Comparative Example 2]
In Comparative Example 2, as the component A, the amount of the chestnut-like silver powder (A-1) was 65.0 g, and as the component B, YL-983U was 25.6 g and ADEKA glycyrrole ED-509S was 5.5 g. , 3.9 g of Curesol C-11Z and a mixture (B-9) were used, and a conductive adhesive not utilizing In-situ polymerization was obtained and evaluated in the same manner as in Comparative Example 1.

[Comparative Example 3]
In Comparative Example 3, the amount of the chestnut-like silver powder (A-1) blended as the component A was 57.0 g, and as the component B, YL-983U was 31.5 g and ADEKA glycyrrole ED-509S was 6.7 g. , 4.8 g of Curesol C-11Z and a mixture (B-10) were used, and a conductive adhesive not utilizing In-Situ polymerization was obtained and evaluated in the same manner as in Comparative Example 1.

[Comparative Example 4]
In Comparative Example 4, the amount of the chestnut-like silver powder (A-1) blended as the component A was 52.0 g, and as the component B, YL-983U was 35.2 g and ADEKA glycyrrole ED-509S was 7.5 g. In the same manner as in Comparative Example 1 except that a mixture (B-11) of 5.4 g of Curesol C-11Z was used, a conductive adhesive not using In-Situ polymerization was obtained and evaluated.

[Comparative Example 5]
In Comparative Example 5, the amount of the chestnut-like silver powder (A-1) blended as the A component was 57.0 g, and the C component was 37.4 g of the blocked isocyanate compound (c2) and 5.6 g of the ADEKA Hardener EH-509S. A conductive adhesive that does not utilize In-Situ polymerization was obtained and evaluated in the same manner as in Comparative Example 1 except that the mixture (C-2) of the above was used.
The blocked isocyanate compound (c2) used as a part of the C component was produced as follows.
First, in a container with a stirrer, 75.3 g of Samprene P-663L (urethane prepolymer solution, isocyanate content 2.9%, manufactured by Sanyo Kasei Kogyo Co., Ltd.) and Sanniks PP-200 (polypropylene glycol, Sanyo Kasei) (Industrial) 20.0 g was accommodated, and the mixture was mixed and stirred for 30 minutes.
Next, 4.7 g of methyl ethyl ketooxime (manufactured by Tokyo Chemical Industry Co., Ltd.) was contained and mixed for 30 minutes. Further, the mixture was mixed in a warm bath at 70 ° C. for 3 hours. Further, it was confirmed by an infrared spectrometer that the peak showing the 2,200 cm- ¹ isocyanate group had disappeared, and a blocked isocyanate compound (c2) was obtained.

[Comparative Example 6]
In Comparative Example 6, the amount of flaky silver powder (A-2) blended as the component A was 50.0 g, and as the component B, YL-983U was 36.6 g and ADEKA glycyrole ED-509S was 7.8 g. , 5.6 g of Curesol C-11Z and a mixture (B-12) were used, and a conductive adhesive not utilizing In-Situ polymerization was obtained and evaluated in the same manner as in Comparative Example 1.

[Comparative Example 7]
In Comparative Example 7, the amount of flaky silver powder (A-2) blended as the component A was 45.0 g, and as the component B, YL-983U was 40.3 g and ADEKA glycyrrole ED-509S was 8.6 g. , A conductive adhesive not utilizing In-Situ polymerization was obtained and evaluated in the same manner as in Comparative Example 1 except that a mixture of 6.1 g of Curesol C-11Z and (B-13) was used.

As described above, according to the present invention, there is provided a conductive adhesive in which the base resin and the region formed by In-Situ polymerization are microphase-separated, and a method for using the same.
Then, the conductive adhesive contains a predetermined amount of conductive particles, and the content of the conductive particles contained in the base resin region is set to φ1 (% by weight), and the region is formed by In-Situ polymerization. When the content of the contained conductive particles is φ2 (% by weight), it is characterized by satisfying a predetermined magnitude relationship (φ1> φ2, etc.).

Therefore, when the conductive adhesive is used, the base resin when heat-treated and the like and the region formed by In-Situ polymerization are stably microphase-separated, and the conductive particles are stable in the base resin. It is presumed that it tends to be unevenly distributed.

Therefore, according to the conductive adhesive or the like of the present invention, since it is unevenly distributed in the base resin, good conductivity and adhesive strength can be obtained even if a relatively small amount of conductive particles are blended, and by extension, the conductive adhesive can be obtained. It is expected that such conductive adhesives will be widely used in various fields.

However, the type of base resin in the conductive adhesive, the type of region formed by In-Situ polymerization, and the surface treatment agent and surface treatment of the conductive particles are appropriately controlled, and the conductive particles and In It has also been separately found that by increasing the affinity with the region formed by -Situ polymerization, the conductive particles can be concentrated and unevenly distributed in the region formed by In-Situ polymerization rather than the base resin. ..
Therefore, depending on the application, such a conductive adhesive can also be preferably used.

10: Conductive particles 12: Monoma for In-Situ polymerization 12a: Region after In-Situ polymerization 14: Monoma for base resin 14a: Base resin after thermal polymerization 20: Conductive adhesive 20a: Conductivity before phase separation Adhesive (conducting adhesive stock solution)
20b: Conductive adhesive after In-Situ polymerization

Claims (8)

A conductive adhesive in which the base resin and the region formed by In-Situ polymerization are microphase-separated.
The conductive adhesive contains conductive particles and
When the content of the conductive particles contained in the base resin is φ1 (% by weight) and the content of the conductive particles contained in the region formed by In-Situ polymerization is φ2 (% by weight), φ1> A conductive adhesive characterized by satisfying the relationship of φ2. When the reaction temperature of the In-Situ polymerization is T1 (° C.) and the reaction temperature of the base resin is T2 (° C.), the absolute value of ΔT (= T2-T1) is in the range of 5 to 50. The conductive adhesive according to claim 1, wherein the value is high. The conductive adhesive according to claim 1 or 2, wherein the base resin is a thermosetting epoxy resin. Any one of claims 1 to 3, wherein the region formed by In-Situ polymerization is derived from a combination of an acrylic monoma and a radical generator, or a combination of a blocked isocyanate compound and an active hydrogen group-containing compound. The conductive adhesive according to the section. The conductive adhesive according to any one of claims 1 to 4, wherein the content of the conductive particles is in the range of 25 to 70% by weight with respect to the total amount. Viscosity is 0.1 to 300 Pa · sec. The conductive adhesive according to any one of claims 1 to 5, wherein the value is within the range of (measurement temperature: 25 ° C.). Conductive adhesive according to any one of claims 1 to 6, characterized in that the specific resistance within a range of ^{1 × 10 -4 ~1 × 10 0} Ω · cm. A method of using a conductive adhesive in which a base resin and an region formed by in-situ polymerization are microphase-separated, the conductive adhesive comprising the following steps (1) to (4). How to use sex adhesive.
(1) A step of preparing a conductive adhesive containing conductive particles and having a microphase separation between the base resin and the region formed by In-Situ polymerization (2) Applying the conductive adhesive to the object to be adhered. (3) A step of heating the conductive adhesive to form a region formed by In-Situ polymerization (4) A microphase of the base resin and the region formed by In-Situ polymerization. When the content of the conductive particles contained in the base resin is φ1 (% by weight) and the content of the conductive particles contained in the region formed by In-Situ polymerization is φ2 (% by weight) while being separated. , Φ1> φ2 relationship

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