JP5200662B2 - Conductive adhesive and electronic components - Google Patents

Description

  The present invention relates to a conductive adhesive and an electronic component using the same.

Conventionally, a conductive adhesive is often used when an electronic element chip such as a capacitor element is bonded to an external electrode.
As such a conductive adhesive, a conductive adhesive containing an epoxy resin, a phenol resin, an imidazole compound, and conductive metal particles has been proposed (for example, Patent Document 1).
Also known is a technique for improving the conductivity by removing an oxide film removing agent such as organic carboxylic acid in the conductive adhesive to remove the surface oxide film of the conductive metal particles (for example, Patent Document 2).
JP 2000-192000 A Japanese Patent Laid-Open No. 8-30212

However, in the conventional conductive adhesive containing a phenol resin, as described in Patent Document 1, it is necessary to mix each component under heating of, for example, about 50 ° C. during the production of the conductive adhesive. , It took time to manufacture. In addition, in order to dissolve the phenol resin, it was necessary to use a large amount of reactive diluent, but the conductive adhesive containing a large amount of reactive diluent has insufficient adhesive strength of the cured product. There was a problem of becoming.
Accordingly, the present inventors have improved the labor during production and the adhesive strength of the cured product by selecting liquid epoxy resins and phenolic resins at room temperature, and further oxidized such conductive adhesives. We are investigating a technique to achieve higher conductivity by blending a film remover.

  However, a conductive adhesive using a liquid epoxy resin and a phenol resin at room temperature has a very high reactivity, and when a known oxide film remover such as an organic carboxylic acid is blended with this, a conductive adhesive is used. The oxide film remover reacts with the epoxy resin during the manufacture and before use, and further acts as an accelerator for the reaction between the epoxy resin and the phenol resin, causing gelation or thickening. There was a problem.

  The present invention has been made in view of the above circumstances, and even when an oxide film remover is blended with a conductive adhesive containing a liquid epoxy resin and a phenol resin at room temperature, the gel before production or use It is an object of the present invention to provide a conductive adhesive that can be prevented from being thickened and thickened and has good conductivity, and an electronic component using the same.

  As a result of intensive studies, the present inventors have produced a specific amount of a latent glutaric acid generating compound as an oxide film removing agent, thereby producing a conductive adhesive containing a liquid epoxy resin and a phenol resin at room temperature. It has been found that gelation and thickening before use and use are suppressed, and that the conductivity is good, and the present invention has been completed.

That is, the conductive adhesive of the present invention is a conductive material containing an epoxy resin that is liquid at room temperature, a phenol resin that is liquid at room temperature, a reactive diluent, an imidazole compound, and silver powder and / or silver-coated metal powder. The adhesive is characterized by further containing a latent glutaric acid generating compound in the range of 0.05 to 5% by mass.
The electronic component of the present invention is manufactured using the conductive adhesive.
In the present invention, “room temperature” means a range of 10 to 40 ° C.

  According to the present invention, even when an oxide film remover is added to a conductive adhesive containing an epoxy resin and a phenol resin that are liquid at room temperature, gelation and thickening before production and use are suppressed. Further, it is possible to provide a conductive adhesive having good conductivity and an electronic component using the same.

Hereinafter, the present invention will be described in detail.
The conductive adhesive of the present invention contains an epoxy resin, a phenol resin, a reactive diluent, an imidazole compound, and silver powder and / or silver-coated metal powder acting as conductive metal particles, and further an oxide film It contains a latent glutaric acid generating compound as a remover.

The epoxy resin used in the present invention is contained in the conductive adhesive as a binder and is liquid at room temperature.
Examples of such epoxy resins include bisphenol F-type epoxy resins, bisphenol A-type epoxy resins, urethane-modified epoxy resins, rubber-modified epoxy resins, naphthalene-based, phenol novolac-based epoxy resins, and phthalate-based epoxy resins. Is mentioned. Of these, bisphenol F type epoxy resins and phthalate ester type epoxy resins are preferred. These epoxy resins may be used alone or in combination of two or more.
The content of the epoxy resin is preferably 2 to 10% by mass and more preferably 3 to 8% by mass in 100% by mass of the conductive adhesive. When the lower limit value of the content of the epoxy resin is smaller than the above value, the adhesive strength becomes weak and it becomes difficult to function as an adhesive. On the other hand, when the upper limit value of the content is larger than the above value, the connection of silver powder and / or silver-coated metal powder becomes poor, and it becomes difficult to obtain conductivity.

The phenol resin used in the present invention is contained in a conductive adhesive as a curing agent and is liquid at room temperature. Since the phenol resin that is liquid at room temperature readily dissolves in other components, it is not necessary to use a large amount of the reactive diluent described later, and the content of the reactive diluent can be reduced. As a result, the adhesive strength of the cured product obtained by curing the conductive adhesive can be improved.
Moreover, a conductive adhesive can be made into a solventless type adhesive by using a liquid phenol resin at room temperature.

Examples of such a phenol resin include a liquid novolac type phenol resin.
The content of the phenol resin is preferably 2 to 10% by mass and more preferably 3 to 8% by mass in 100% by mass of the conductive adhesive. When the lower limit of the phenol resin content is smaller than the above value, the adhesive strength of the conductive adhesive cannot be sufficiently increased. On the other hand, when the upper limit value of the content is larger than the above value, the resistance under high temperature and high humidity or heat cycle increases.

    Moreover, it is preferable that 50-250 mass parts is contained with respect to 100 mass parts of said epoxy resins, and, more preferably, a phenol resin is 80-150 mass parts. If the content of the phenol resin with respect to the epoxy resin is within the above range, the balance between the content of the epoxy resin (main agent) and the phenol resin (curing agent) becomes better, the conductive adhesive becomes easier to cure, and the adhesive strength It will be easier to improve.

In the present invention, the phenol resin that is liquid at room temperature may contain one or more phenol resins that are solid at room temperature within a range that does not impair the properties of the phenol resin.
Examples of the phenol resin solid at room temperature include cresol novolac resin, dicyclopentadiene phenol resin, terpene phenol resin, triphenolmethane resin, and phenol aralkyl resin.
The content of the phenol resin that is solid at room temperature is preferably 0 to 20 parts by mass with respect to 100 parts by mass of the phenol resin that is liquid at room temperature.

    Reactive diluents include glycidyl orthotoluidine, ethylene glycol diglycidyl ether, 2-ethylhexyl glycidyl ether, glycidyl methacrylate, cyclohexanedimethanol diglycidyl ether, trimethylolpropane triglycidyl ether, neopentyl glycol diglycidyl ether, phenyl glycidyl ether Polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and the like. Of these, glycidyl orthotoluidine is preferable. These reactive diluents may be used alone or in combination of two or more.

    The content of the reactive diluent is preferably 2 to 10% by mass and more preferably 3 to 8% by mass in 100% by mass of the conductive adhesive. When the lower limit value of the content of the reactive diluent is smaller than the above value, the viscosity of the conductive adhesive becomes too high, and the dispersibility of silver powder and / or silver-coated metal powder described later is lowered. As a result, the conductive adhesive is difficult to apply, and workability is reduced. On the other hand, when the upper limit value of the content is larger than the above value, the cured product of the conductive adhesive becomes brittle and the adhesive strength decreases.

The imidazole compound is contained in the conductive adhesive as a curing accelerator.
When the imidazole compound is contained, the curability of the conductive adhesive becomes good, and as a result, the heat resistance of the cured product is improved.
Examples of such imidazole compounds include 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and 4,4′-methylenebis (2-ethyl-5-methylimidazole). And imidazole-based epoxy curing accelerators such as 2-heptadecylimidazole. These imidazole compounds may be used alone or in combination of two or more.

    The content of the imidazole compound is preferably 0.05 to 0.9 mass%, more preferably 0.1 to 0.5 mass%, and 0.2 to 0.4 mass% in 100 mass% of the conductive adhesive. % Is more preferable. When the lower limit of the content of the imidazole compound is smaller than the above value, curability is lowered. On the other hand, when the upper limit value of the content is larger than the above value, when the conductive adhesive is temporarily cured, the setting range of the temporary curing conditions (such as the temporary curing time and the temporary curing temperature) is narrowed, and the workability is lowered.

As the conductive metal particles, at least one of silver powder and silver-coated metal powder is used. Examples of the silver-coated metal powder that can be used include copper powder, silver-plated copper powder obtained by applying silver plating to nickel powder, and silver-plated nickel powder.
The shape of the silver powder and / or silver-coated metal powder may be substantially spherical or flaky, but is preferably flaky. Although there is no restriction | limiting in particular in a particle diameter, 1-20 micrometers is preferable from a conductive point, and 3-10 micrometers is more preferable. Moreover, the tap density of silver powder and / or silver-coated metal powder is preferably 4.2~6.0g / cm ^3, more preferably 4.5~5.8g / cm ^3. When the lower limit value of the tap density is smaller than the above value, the viscosity of the obtained conductive adhesive is increased, and workability is lowered. On the other hand, when the upper limit value of the tap density is larger than the above value, the production of the conductive adhesive tends to be difficult.
The content of the silver powder and / or the silver-coated metal powder is preferably 70 to 92% by mass and more preferably 75 to 90% by mass in 100% by mass of the conductive adhesive. When the lower limit of the content of silver powder and / or silver-coated metal powder is smaller than the above value, the connection of silver powder and / or silver-coated metal powder becomes poor, and it becomes difficult to obtain conductivity. On the other hand, when the upper limit of the content is larger than the above value, the adhesive strength is weakened and the cost is increased more than necessary.
In addition to silver powder and / or silver coat metal powder, other particles such as nickel powder and copper powder may be used as the conductive metal particles as long as the characteristics are not impaired.

    The mass ratio (solid content ratio) of the silver powder and / or silver-coated metal powder and the resin component (that is, the total of the epoxy resin and the phenol resin) is as follows: silver powder and / or silver-coated metal powder: resin component = 80 : 20 to 96: 4 is preferable, and 85:15 to 93: 7 is more preferable. If the mass ratio of the silver powder and the resin component is within the above range, the cured product is excellent in both conductivity and adhesive strength.

The latent glutaric acid generating compound used in the present invention is blended as an oxide film removing agent and improves the conductivity of the conductive adhesive. The glutaric acid reacts with the vinyl ether compound to have glutaric acid. A compound in which a carboxyl group is blocked with a vinyl ether compound (block carboxylic acid).
In the conductive adhesive in which the latent glutaric acid generating compound is blended, high conductivity is exhibited without causing gelation or thickening during the production or use of the conductive adhesive. The reason is considered as follows. That is, in the latent glutaric acid compound, the activity of the carboxylic acid is blocked by the vinyl ether compound, so that it reacts with the epoxy resin or reacts with the epoxy resin and the phenol resin only when blended in the conductive adhesive. Does not act as an accelerator. Therefore, gelation and thickening before production and use are suppressed. On the other hand, when the conductive adhesive compounded with this latent glutaric acid generating compound is heated and cured at the time of use, the block is released by heating and the activity of carboxylic acid is expressed, thereby removing the oxide film. It is considered that the effect of improving conductivity is exhibited.
When the latent glutaric acid generating compound is blended in this way, the conductivity of the conductive adhesive is improved, so that the amount of silver powder and / or silver-coated metal powder used to obtain a certain level of conductivity can be kept low. It is also possible to provide a conductive adhesive that is advantageous in terms of cost.

  Thus, the excellent effect that gelation and thickening before production and use are suppressed and high conductivity is exhibited at the time of use is obtained when a latent glutaric acid generating compound is used as an oxide film removing agent. Can only be obtained. For example, when a latent adipic acid generating compound or a latent oleic acid generating compound in which a carboxyl group is similarly blocked is used, high conductivity is obtained, but the effect of suppressing gelation and thickening is obtained. Absent.

Examples of the vinyl ether compound used for the production of the latent glutaric acid generating compound include aliphatic vinyl ether, aliphatic vinyl thioether, cyclic vinyl ether, and cyclic vinyl thioether.
Examples of the aliphatic vinyl ether include monovinyl ether compounds such as methyl vinyl ether, ethyl vinyl ether, isopropyl vinyl ether, n-propyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl vinyl ether; butanediol divinyl ether, cyclohexane Diol divinyl ether, cyclohexane dimethanol divinyl ether, diethylene glycol divinyl ether, trimethylene glycol divinyl ether, triethylene glycol divinyl ether, 1,4-bisvinyloxymethylcyclohexene, tetraethylene glycol divinyl ether, ethylene glycol divinyl ether, hexanediol di Bini Ether, polyethylene glycol divinyl ether, pentanediol divinyl ether, hexanediol divinyl ether, 1,4-cyclohexanedimethanol divinyl ether, nonanediol divinyl ether, 1,4-benzene divinyl ether, bisphenol A divinyl ether, bisphenol F divinyl ether, etc. Divinyl ether compounds; trivinyl ether compounds such as trimethylolpropane trivinyl ether; and tetravinyl ether compounds such as pentaerythritol tetravinyl ether. Examples of the aliphatic vinyl thioether include thio compounds corresponding to the examples of the aliphatic vinyl ether.

  Examples of the cyclic vinyl ether include 2,3-dihydrofuran, 3,4-dihydrofuran, 2,3-dihydro-2H-pyran, 3,4-dihydro-2H-pyran, and 3,4-dihydro-2-methoxy. -2H-pyran, 3,4-dihydro-4,4-dimethyl-2H-pyran-2-one, 3,4-dihydro-2-ethoxy-2H-pyran, 3,4-dihydro-2H-pyran-2 -Sodium carboxylate etc. are mentioned. Examples of the cyclic vinyl thioether include thio compounds corresponding to the examples of the cyclic vinyl ether. Among these, n-propyl vinyl ether, n-butyl vinyl ether, 2-ethylhexyl vinyl ether, 1,4-butanediol divinyl ether, tetratetrahydrochloride, from the viewpoint of the availability of raw materials and the decomposition start temperature of the resulting latent glutaric acid generating compound. Ethylene glycol divinyl ether and butanediol divinyl ether are preferred.

The latent glutaric acid generating compound can be obtained by reacting glutaric acid with a vinyl ether compound. Specifically, the reaction can be carried out under the conditions of a reaction temperature of 30 to 200 ° C., preferably 50 to 150 ° C., a reaction time of 10 minutes to 6 hours, preferably 20 minutes to 5 hours. The end point of the reaction is preferably, for example, when the acid value of the reaction system is measured and the acid value becomes 10 mgKOH / g or less, particularly when the acid value becomes 5 mgKOH / g or less. Is preferably 10 mgKOH / g or less, particularly preferably 5 mgKOH / g or less. At this time, it is particularly preferable to carry out the reaction so that all of the carboxyl groups of glutaric acid are blocked. However, even if a part of the carboxyl groups remain, for example, at the ends, the object of the present invention must be impaired. Don't worry.
The reaction ratio of glutaric acid and the vinyl ether compound is usually 1.0: 0.5 to 5.0, preferably 1.0: 1.0 to 4.0, particularly preferably 1.0: 1. 0-3.0. Moreover, the mass average molecular weight of the latent glutaric acid generating compound is usually 500 to 500,000, particularly preferably 1,000 to 50,000.

  The latent glutaric acid generating compound preferably used is a case where the thermal decomposition start temperature is 170 ° C. or less and a conductive adhesive containing the latent glutaric acid generating compound is heated and cured at the time of use. May be Santa Cid FK-16 (trade name) manufactured by Nippon Oil & Fats Co., Ltd., in which the block is readily removed by heating and the carboxylic acid activity is easily expressed. Here, the thermal decomposition starting temperature refers to a temperature at which the mass is reduced by 1% when the mass change is measured while heating the sample at 10 ° C./min.

  The content of the latent glutaric acid generating compound is 0.05 to 5% by mass, preferably 0.1 to 3% by mass, in 100% by mass of the conductive adhesive. When the lower limit value of the content of the latent glutaric acid generating compound is smaller than the above value, it is difficult to obtain the conductivity improving effect by the oxide film removing agent. On the other hand, when the upper limit of the content is larger than the above value, the adhesive strength is weakened and the hardness of the cured product tends to be lowered.

The conductive adhesive of the present invention may appropriately contain an optional component such as a coupling agent as long as the effects of the present invention are not impaired.
In the present invention, a solvent-type adhesive may be prepared by containing a solvent. In this case, the solvent is not particularly limited as long as it is used for an adhesive, and known solvents can be used.
However, since the conductive adhesive of the present invention contains an epoxy resin that is liquid at room temperature as an epoxy resin and a phenol resin that is liquid at room temperature as a phenol resin, as described above, as a solvent-free adhesive that does not contain a solvent. Can be used. The conductive adhesive of the present invention may be a solventless type or a solvent type, but is preferably used as a solventless type adhesive.

When the conductive adhesive is a solventless type, an increase in the viscosity of the conductive adhesive due to the volatilization of the solvent can be suppressed as compared with the solvent type. For this reason, even when the conductive adhesive is applied on the electrode by screen printing or metal mask printing, it is possible to effectively prevent the printed surface from being blurred. Further, even in the case of a coating method using a dispenser, the needle tip can be prevented from drying, so that the discharge amount of the conductive adhesive can be kept constant.
However, since the application method using a dispenser is usually suitable for applying a conductive adhesive having a low viscosity, the conductive adhesive easily spreads on the electrode after application. On the other hand, screen printing and metal mask printing can be applied to a conductive adhesive having a high viscosity. Therefore, when a conductive adhesive is applied, it is preferably applied by screen printing or metal mask printing. Among these, screen printing is preferable.

The conductive adhesive of the present invention includes the above-described epoxy resin, phenol resin, reactive diluent, imidazole compound, silver powder and / or silver-coated metal powder, and latent glutaric acid generating compound. It can be produced by mixing with a mixer or roll mill. Under the present circumstances, it is preferable to prepare so that the viscosity of the conductive adhesive obtained may be 80-800 dPa * s.
In such a conductive adhesive, a phenol resin that is liquid at room temperature is used, so it is not necessary to preheat the epoxy resin in advance, and it is not necessary to use a large amount of reactive diluent. . Therefore, simple manufacture and improvement in adhesive strength are possible.
Further, as the oxide film removing agent, a latent glutaric acid generating compound in which the activity of carboxylic acid is blocked is blended. Therefore, the reaction between the latent glutaric acid-generating compound and the phenol resin does not proceed during the production or before use of the conductive adhesive, causing gelation and thickening, and is maintained at 23 ° C. for 72 hours. The subsequent viscosity is also maintained at 80 to 800 dPa · s, and the coating property of the conductive adhesive is kept good. When the conductive adhesive is heated and cured, the block is removed from the latent glutaric acid generating compound by heating, and the carboxylic acid activity is exhibited. A conductive adhesive.

The conductive adhesive of the present invention can be used for various applications, but is suitable for bonding an electronic element chip to an external electrode.
Since the electronic component of the present invention is manufactured by using the above-described conductive adhesive, the adhesive strength is high. Applications of electronic components include, for example, passive components such as capacitors, coils, and transformers, and semiconductor device components such as LSIs (Large Scale Integrated Circuits), diodes, and transistors.
Examples of the electronic element chip include capacitor elements, semiconductor chips such as CSP, BGA, and FC. Moreover, it does not restrict | limit especially as an external electrode which apply | coats a conductive adhesive, For example, the electrode containing metals, such as gold | metal | money, silver, tin, copper, is mentioned.

    The method for producing the electronic component is not particularly limited. For example, after applying a conductive adhesive on the external electrode by the printing method described above, an electronic element chip is placed on the conductive adhesive, and the conductive component is conductive. Examples include a method of curing (main curing) the adhesive. In addition, for the purpose of improving the adhesive strength, a load process for applying a load to the electronic element chip is provided before the conductive adhesive is fully cured to improve the wettability of the surface of the electronic element chip. Further, a temporary curing step for temporarily curing the conductive adhesive may be further provided.

    The thickness of the conductive adhesive applied on the external electrode is preferably 20 to 500 μm, more preferably 20 to 120 μm, and even more preferably 30 to 100 μm. When the lower limit of the film thickness is smaller than the above value, the adhesive strength is weakened, and the adhesion between the electronic element chip and the external electrode tends to be lowered. On the other hand, if the upper limit value of the film thickness is larger than the above value, the cost increases more than necessary.

The main curing temperature when the conductive adhesive is main-cured is not particularly limited, but is preferably 130 to 250 ° C, and more preferably 140 to 200 ° C. When the lower limit value of the main curing temperature is smaller than the above value, the conductive adhesive is not sufficiently cured, and the adhesion between the electronic element and the electrode is lowered. On the other hand, when the upper limit value of the main curing temperature is larger than the above value, the cost is increased more than necessary.
The main curing time is not particularly limited, but is preferably 5 to 60 minutes, for example, and more preferably 10 to 40 minutes. When the lower limit of the main curing time is smaller than the above value, the conductive adhesive is not sufficiently cured, and the adhesion between the electrode and the electronic element tends to be lowered. On the other hand, if the upper limit value of the main curing time is larger than the above value, the cost is increased more than necessary.

<Examples 1 to 10, Comparative Examples 1 to 7>
(Manufacture of conductive adhesive)
Bisphenol F type epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., “EP807”) as a liquid epoxy resin at room temperature and liquid novolak type as a liquid phenol resin at room temperature with the blending amount (mass%) shown in the table Phenolic resin (Maywa Kasei Co., Ltd., “MEH8005”), glycidyl orthotoluidine (Nippon Kayaku Co., Ltd., “GOT”) as a reactive diluent, and imidazole epoxy (curing accelerator) as an imidazole compound A curing accelerator (“2PHZ” manufactured by Shikoku Kasei Kogyo Co., Ltd.), the following flake silver powders (1) to (6) as conductive metal particles, and the following compound as an oxide film remover are mixed in a roll mill to conduct electricity. Adhesive was produced.

(Conductive metal particles)
Flake silver powder (1): manufactured by Ferro Japan, “SF38”, tap density: 4.8 g / cm ³
・ Flake silver powder (2): manufactured by Ferro Japan, “SF37”, tap density: 4.9 g / cm ³
・ Flake silver powder (3): manufactured by Ferro Japan, “SF26”, tap density: 4.0 g / cm ³
・ Flake silver powder (4): Fukuda Metal Foil Powder Industry Co., Ltd., “AgC-GS”, tap density: 3.1 g / cm ³
・ Flake silver powder (5): Fukuda Metal Foil Powder Co., Ltd., “AgC-A”, tap density: 3.3 g / cm ³
・ Flake silver powder (6): manufactured by Ferro Japan, “SF78NFA”, tap density: 5.5 g / cm ³

(Oxide film remover)
-Potential glutaric acid generating compound: "Santa Cid FK-16" manufactured by NOF Corporation: Mass ratio of glutaric acid and vinyl ether compound (glutaric acid / vinyl ether compound) = 43.6 / 56.4, acid equivalent is 152. 1g / mol
-Potential adipic acid generating compound: "Santa Cid FK-05" manufactured by NOF Corporation: Mass ratio of adipic acid and vinyl ether compound (adipic acid / vinyl ether compound) = 38.3 / 61.7, acid equivalent is 191 g / mol
・ Latent oleic acid generating compound: “Santa Cid FK-03” manufactured by NOF Corporation: Mass ratio of oleic acid to vinyl ether compound (oleic acid / vinyl ether compound) = 70.6 / 29.4, acid equivalent is 393 g / mol
・ Glutaric acid, succinic acid, fumaric acid

<Measurement>
About the obtained conductive adhesive, the initial viscosity and the viscosity after hold | maintaining at 23 degreeC x 72 hours were measured by the following method.
Also, the obtained conductive adhesive was applied on a glass plate so as to have a width of 1 cm, a length of 8 cm, and a thickness of 30 μm, and cured under conditions of 180 ° C. × 10 minutes, and the pencil hardness of the cured product. The specific resistance was measured by the following method. In addition, the measurement result about the electronic component manufactured using each conductive adhesive shows the same tendency as each measurement result about these conductive adhesives. Therefore, the measurement for each conductive adhesive is used as a substitute test for the measurement of the electronic component.

(Initial viscosity and viscosity after holding at 23 ° C. for 72 hours)
The initial viscosity was measured with a TV-type viscometer (manufactured by Toki Sangyo Co., Ltd.) for the conductive adhesive obtained in each test example. The measurement with a TV viscometer was carried out using a 3 ° cone, a rotation speed of 5 rpm, and a measurement temperature of 23 ° C.
The viscosity after holding at 23 ° C. for 72 hours was measured in the same manner as the initial viscosity after holding the conductive paste obtained in each test example under the conditions of 23 ° C. for 72 hours.
The results are shown in the table. In addition, ○ is a pass.
○: 80 dPa · s or more and less than 800 dPa · s ×: Less than 80 dPa · s or 800 dPa · s or more

(Pencil hardness)
About the hardened | cured material, pencil hardness was measured based on JISK5600.
The results are shown in the table. In addition, ○ is a pass.
○: F or more ×: HB or less

(Adhesive strength)
Conductive adhesive is coated on a glass plate to a width of 1 cm, length of 8 cm, and thickness of 30 μm, and five stainless nuts (made by Nishi Seiko Co., Ltd., “M3”) are arranged on it. And cured at 180 ° C. for 10 minutes. After returning to room temperature, the end of the push-pull gauge shaft made by Aiko Engineering is placed perpendicular to one surface of the nut, and the nut is pushed in the horizontal direction at a speed of 5 ± 0.5 mm / min. The strength at the time was determined. The strength was similarly determined for the five nuts, and the average value of the five nuts was defined as the adhesive strength.
○: 5 N / mm ² or more ×: Less than 5 N / mm ²

(Resistivity)
For the cured product, the resistance value (R), the film thickness (A), the electrode width (B), and the inter-electrode distance (C) were measured, and the specific resistance was calculated by the following formula. The resistance value was measured using a digital multimeter (trade name: R6581D) manufactured by ADVANTEST, and the film thickness was measured using a surface roughness meter (trade name: SE3500) manufactured by Kosaka Laboratory.
ρ = R × {(A × B) / C}
○: Less than 3 × 10 ⁻⁵ Ω · cm ×: 3 × 10 ⁻⁵ Ω · cm or more

<Example 11>
As shown in the table, in the same manner as in Example 3, except that a phthalate ester epoxy resin (manufactured by Nippon Kayaku Co., Ltd., “AK601”) was used as the liquid epoxy resin at room temperature, the conductivity was An adhesive was produced.

As is clear from the table, in the conductive adhesives of each Example in which an appropriate amount of a latent glutaric acid generating compound was blended as an oxide film removing agent, gelation or the like was not observed during production or before curing, and the initial viscosity, 23 Both of the viscosities after holding under the condition of ° C. × 72 hours were appropriate, the conductivity was excellent, and the adhesive strength and pencil hardness were also good.
On the other hand, in a comparative example in which a latent adipic acid generating compound or a latent oleic acid compound is blended as an oxide film removing agent, or in a comparative example in which glutaric acid, succinic acid or fumaric acid in which carboxyl groups are not blocked is blended, Was excellent, but high initial viscosity and gelation were observed.

Claims (2)

A conductive adhesive containing an epoxy resin that is liquid at room temperature, a phenol resin that is liquid at room temperature, a reactive diluent, an imidazole compound, and silver powder and / or silver-coated metal powder,
It further comprises a latent glutaric acid generating compound, which is a compound in which glutaric acid reacts with a vinyl ether compound and the carboxyl group of glutaric acid is blocked with a vinyl ether compound in a range of 0.05 to 5% by mass. Conductive adhesive.   An electronic component manufactured using the conductive adhesive according to claim 1.