KR101600446B1 - Conductive adhesive having conductive polymer and conductive flim thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive adhesive containing a conductive polymer, and more particularly to a conductive adhesive and an adhesive film comprising a metal powder, a conductive polymer and a polymeric binder. INDUSTRIAL APPLICABILITY The conductive adhesive of the present invention can provide a conductive adhesive agent and a conductive adhesive film excellent in adhesion and surface resistance, which are trade-off-related, by adopting a conductive polymer having excellent affinity with a polymeric binder and having conductivity.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a conductive adhesive and an adhesive film comprising a conductive polymer,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive adhesive containing a conductive polymer, and more particularly to a conductive adhesive and an adhesive film comprising a metal powder, a conductive polymer and a polymeric binder.

Recently, as the directivity of the substrate increases with the development of technology, a conductive adhesive excellent in conductivity is required. In recent years, FPCB (FLEXIBLE PRINTED CIRCUITS BOARD) has been used in various fields. As electronic products have become smaller and lighter in weight, electronic parts developed have excellent workability, strong heat resistance, rust resistance and chemical resistance, FPCB is suitable. Specifically, such FPCB is a key component of all electronic products such as camera, COMPUTER and peripheral devices, HAND PHONE, VIDEO & AUDIO device, CAMCORDER. PRINTER, DVD, TFT LCD, satellite equipment, military equipment, medical equipment and so on. The FPCB can be three-dimensionally wired by itself, making it possible to reduce the size and weight of the device. Further, the FPCB has high durability against repeated bending, enables high-density wiring, has no wiring error, is good in assembly, and has high reliability. In addition, FPCB has advantages that it can be manufactured by continuous production method.

In the case of FPCB, a conductive adhesive sheet used for electrically interconnecting a circuit board body such as a flexible printed wiring board (FPC) and circuit components such as a reinforcing plate, a circuit board body, circuit components, and the like are electrically interconnected A conductive adhesive used for a circuit board is required. Such a conductive adhesive agent is used for hole filling of a substrate, and generally includes conductive particles in a thermosetting resin. As the conductive particles, a metal powder or the like is used. There has been a demand for a conductive adhesive excellent in conductivity while increasing the degree of directivity of a substrate in accordance with the development of technology.

Japanese Unexamined Patent Publication No. 2006-298954 discloses a conductive adhesive material containing a low melting point metal powder, but there is a problem that the conductivity is lowered due to the binder located between the metal powders.

An object of the present invention is to provide a conductive adhesive containing a conductive polymer for improving conductivity of a conductive adhesive.

In order to solve the above problems, the present invention provides a conductive adhesive comprising a metal powder, a conductive polymer, and a polymeric binder.

According to a preferred embodiment of the present invention, the conductive polymer may be a conductive polymer powder composed of a conductive polymer resin; A core-shell structure conductive polymer composite having a carbon core coated with a conductive polymer resin; And a conductive polymer resin solution; And mixtures of two or more thereof.

Such a conductive polymer resin is not particularly limited in its kind, but examples thereof include polypyrrole, polythiophene, polyaniline, polyacetylene, polyphenylene sulfide, polyphenylene vinylene, polyindole, polypyrylene. It is preferable to use one compound selected from polycarbazole, polyazulene, polyazepine, polyfluorene, polynaphthalene, and polyethylene dioxythiophene, or a mixture of two or more thereof.

According to a preferred embodiment of the present invention, the kind of the metal powder is not particularly limited, but it may include a low melting point metal, and specifically, gold, silver, copper, nickel, indium, tin, lead, Bismuth, or a mixture of two or more thereof, or an alloy thereof.

According to a preferred embodiment of the present invention, the polymer binder may be a compound selected from the group consisting of an acrylate resin, an epoxy resin, a polyester, a polyurethane, a polycarbonate, a polyamide, a polyimide and a polyether, Etc., but the present invention is not limited thereto.

The present invention provides a conductive adhesive film comprising a conductive adhesive layer comprising a metal powder, a conductive polymer, and a polymeric binder.

According to a preferred embodiment of the present invention, the conductive polymer may be a conductive polymer powder composed of a conductive polymer resin; A core-shell structure conductive polymer composite having a carbon core coated with a conductive polymer resin; And a conductive polymer resin solution; And mixtures of two or more thereof.

Such a conductive polymer resin is not particularly limited in its kind, but examples thereof include polypyrrole, polythiophene, polyaniline, polyacetylene, polyphenylene sulfide, polyphenylene vinylene, polyindole, polypyrylene. It is preferable to use one compound selected from polycarbazole, polyazulene, polyazepine, polyfluorene, polynaphthalene, and polyethylene dioxythiophene, or a mixture of two or more thereof.

According to a preferred embodiment of the present invention, the kind of the metal powder is not particularly limited, but it may include a low melting point metal, and specifically, gold, silver, copper, nickel, indium, tin, lead, Bismuth, or a mixture of two or more thereof, or an alloy thereof.

According to a preferred embodiment of the present invention, the polymer binder may be a compound selected from the group consisting of an acrylate resin, an epoxy resin, a polyester, a polyurethane, a polycarbonate, a polyamide, a polyimide and a polyether, Etc., but the present invention is not limited thereto.

INDUSTRIAL APPLICABILITY The conductive adhesive of the present invention can provide a conductive adhesive agent and a conductive adhesive film excellent in adhesion and surface resistance, which are trade-off-related, by adopting a conductive polymer having excellent affinity with a polymeric binder and having conductivity.

Fig. 1 is a graph showing adhesion strengths of specimens for measuring an adhesive strength using conductive adhesives of Examples and Comparative Examples.
Fig. 2 is a graph showing the surface resistivity of a specimen for measuring an adhesion force using the conductive adhesive of Examples and Comparative Examples.

Hereinafter, the present invention will be described in detail with reference to the drawings. The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms and the inventor may appropriately define the concept of the term in order to best describe its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.

The conductive adhesive of the present invention includes a metal powder, a conductive polymer, and a polymeric binder. The conductive adhesive of the present invention is excellent in conductivity performance, including a conductive polymer containing a conductive polymer having conductivity and excellent affinity with a polymeric binder.

The metal powder is excellent in conductivity, but the affinity with the polymer binder is not high. Therefore, as the content of the metal powder increases, the adhesion decreases. In order to secure the adhesion, when the content of the metal powder is decreased, This is a trade-off relationship that degrades. In addition, since the affinity of the metal powder with the polymer binder is not high, it is not easy to uniformly disperse the metal powder in the manufacturing process, and the non-conductive polymer binder interferes with the contact between the metal powder particles, thereby deteriorating the conductivity.

Thus, the conductive adhesive of the present invention uses a conductive polymer for ensuring adhesiveness without lowering the conductivity. The conductive polymer generally refers to a polymer having a conductivity of at least 10 ^-7 Scm ^-1 (a value equal to or larger than a semiconductor). In many cases, a high conductivity is obtained by doping an electron acceptor or an electron donor to a polymer. Since the conductive polymer has an affinity with the polymer binder and conductivity at the same time, the conductive polymer is located between the metal powder particles, so that the conductivity can be prevented from lowering. That is, since the charge moves through a path having a small resistance, the conductive polymer having a relatively smaller resistance than the polymer binder provides a path for transferring charges, thereby facilitating charge flow.

According to a preferred embodiment of the present invention, the conductive polymer may be a conductive polymer powder composed of a conductive polymer resin; A core-shell structure conductive polymer composite having a carbon core coated with a conductive polymer resin; And a conductive polymer resin solution; And mixtures of two or more thereof.

The conductive polymer powder composed of the conductive polymer resin is a generally used conductive polymer in the form of powder. The average particle size of the conductive polymer powder is not particularly limited, It is preferable to use a conductive polymer powder having a mean particle size in a range of 0.01 to 10 mu m depending on the application.

The conductive polymer composite having the core-shell structure in which the conductive polymer resin is coated on the carbon core has a merit of excellent conductivity compared to the conductive polymer powder composed only of the conductive polymer resin since the carbon core having excellent conductivity is used therein. The average particle size of the conductive polymer composite is not particularly limited, It is preferable to use a conductive polymer complex having a mean particle size in various ranges depending on the application.

In the case of the conductive polymer resin solution, the conductive polymer resin is dispersed in the solvent. Since the conductive polymer resin is in the form of a dispersion solution, there is an advantage that the manufacturing process can be easily performed. That is, in the process of producing the conductive adhesive of the present invention, it is easy to form a uniform composition with the polymer binder or the metal powder.

Also, in the conductive polymer resin dispersed in a solvent having a high degree of dispersion, the polymer chain is unfolded by the second conductive doping principle. As a result, the conductive polymer dispersed in the solvent can further enhance the bonding between the polymer binder and the metal powder, thereby further improving the adhesion and conductivity of the conductive adhesive.

In a preferred embodiment of the present invention, the conductive polymer resin solution may be used together with the conductive polymer powder or the conductive polymer composite, if necessary. For example, when toluene is used as a solvent, the PEDOT-PSS powder has a low degree of dispersion, so that the PEDOT-PSS powder is aggregated or submerged in the solvent. do. On the other hand, polyaniline has a high degree of dispersion and is present as a stable dispersion liquid. This is not limited to the conductive polymer type but also to the kind of the conductive polymer and the dopant as the first doping agent.

The conductive polymer is not particularly limited, but the conductive polymer resin may be selected from the group consisting of polypyrrole, polythiophene, polyaniline, polyacetylene, polyphenylene sulfide, polyphenylene vinylene, polyindole, It is preferable to use one compound selected from polycarbazole, polyazulene, polyazepine, polyfluorene, polynaphthalene, and polyethylene dioxythiophene, or a mixture of two or more thereof.

The metal powder may include a high melting point metal such as gold, silver, copper and nickel and a low melting point metal such as indium, tin, lead and bismuth, , Copper, nickel, indium, tin, lead and bismuth, or a mixture of two or more thereof, or an alloy thereof. Particularly, the low melting point metal among the metal powders means a metal material which is melted at a melting point (about 327.4 ° C) of lead (Pb). The low melting point metal is melted at a low temperature to form an intermetallic compound with the plating surface of the main body of the circuit board, thereby improving the electrical conductivity and enhancing the adhesion with the plating surface. The average particle size of the metal powder is not particularly limited, but it is preferably 10 to 100 占 퐉, and metal powder having various average particle sizes may be used depending on the application.

According to a preferred embodiment of the present invention, the polymer binder may be a compound selected from the group consisting of an acrylate resin, an epoxy resin, a polyester, a polyurethane, a polycarbonate, a polyamide, a polyimide and a polyether, Etc., but the present invention is not limited thereto.

These polymeric binders impart adhesiveness to the conductive adhesive, and two or more polymers of a thermoplastic resin and a thermosetting resin can be mixed and used for adhesion at a low temperature and adhesion at a high temperature.

The present invention provides a conductive adhesive film comprising a conductive adhesive layer comprising a metal powder, a conductive polymer, and a polymeric binder. The conductive adhesive film has a conductive adhesive layer including a metal powder, a conductive polymer, and a polymer binder formed on at least one side of the base film. The conductive adhesive film of the present invention includes a conductive polymer including a conductive polymer having conductivity and excellent affinity with a metal powder, and thus has excellent conductivity. The base film is not particularly limited, but a polymer film such as PET can be used.

According to a preferred embodiment of the present invention, the conductive polymer may be a conductive polymer powder composed of a conductive polymer resin; A core-shell structure conductive polymer composite having a carbon core coated with a conductive polymer resin; And a conductive polymer resin solution; And mixtures of two or more thereof. Such a conductive polymer resin is not particularly limited in its kind, but examples thereof include polypyrrole, polythiophene, polyaniline, polyacetylene, polyphenylene sulfide, polyphenylene vinylene, polyindole, polypyrylene. It is preferable to use one compound selected from polycarbazole, polyazulene, polyazepine, polyfluorene, polynaphthalene, and polyethylene dioxythiophene, or a mixture of two or more thereof. According to a preferred embodiment of the present invention, the kind of the metal powder is not particularly limited, but it may include a low melting point metal, and specifically, gold, silver, copper, nickel, indium, tin, lead, Bismuth, or a mixture of two or more thereof, or an alloy thereof. According to a preferred embodiment of the present invention, the polymer binder may be a compound selected from the group consisting of an acrylate resin, an epoxy resin, a polyester, a polyurethane, a polycarbonate, a polyamide, a polyimide and a polyether, Etc., but the present invention is not limited thereto.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to examples. However, the embodiments according to the present invention can be modified into various other forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. The embodiments of the present invention are provided to enable those skilled in the art to more fully understand the present invention.

Example

Production Example 1. Preparation of polymer binder

Compounds were prepared according to the composition ratios shown in Table 1, and uniformly stirred to prepare polymer binders.

No. ingredient Content (parts by weight) One Polyester (ES-360M manufactured by SKYBON, Tg 17 DEG C, number average molecular weight 32,000) 5.0 2 Cresol novolac epoxy (YDCN-500-80P, 190-220g / eq, softening point 75-85) 10.0 3 Bisphenol A epoxy (YD-011, equivalent weight 450-500 g / eq, softening point 60-70) 10.0 4 Epoxy (KSR-177 made by Kukdo Chemical Co., 190-220g / eq equivalent) 5.0 5 Dicyandiamide (Air Products Dicyanex 1400F, D50 = 5 占 퐉) 2.0 6 Imidazole compounds (Imicure HAPI, Air Products 220 mg KOH / g) 1.0 7 toluene 33.5 8 Methyl ethyl ketone 33.5 Sum 100

Comparative Examples 1-3. Preparation of Conductive Adhesive Containing Conductive Polymer

Compounds were prepared at the composition ratios shown in Table 2 and uniformly stirred to prepare the products of Comparative Examples 1-3 which were conductive adhesives.

No. ingredient Comparative Example 1 Comparative Example 2 Comparative Example 3 One toluene 29.0 24.0 19.0 2 The polymer binder of Production Example 1 50.0 50.0 50.0 3 ESCC-F300 "(Ag-Cu Flake / D50 = 35 mu m) 20 25 30 4 Everchem Tex - Product "Didim-52" (Anti-Settling agent) 1.0 1.0 1.0 Sum 100.0 100.0 100.0

Examples 1-3. Preparation of Conductive Adhesive Containing Conductive Polymer Powder

The compounds were prepared in the composition ratios shown in Table 3 below and uniformly stirred to prepare the products of Examples 1-3 as conductive adhesives.

No. ingredient Example 1 Example 2 Example 3 One toluene 28.0 23.0 18.0 2 The polymer binder of Production Example 1 50.0 50.0 50.0 3 Agfa - Product "Orgacon DRY" (PEDOT / PSS Pellet) 1.0 1.0 1.0 4 ESCC-F300 "(Ag-Cu Flake / D50 = 35 mu m) 20 25 30 5 Everchem Tex - Product "Didim-52" (Anti-Settling agent) 1.0 1.0 1.0 Sum 100.0 100.0 100.0

Examples 4-6. Preparation of Conductive Adhesive Containing Conductive Polymer Powder

Compounds were prepared at the composition ratios shown in Table 4 and uniformly stirred to prepare conductive adhesive products of Examples 4-6.

No. ingredient Example 4 Example 5 Example 6 One toluene 27.0 22.0 17.0 2 The polymer binder of Production Example 1 50.0 50.0 50.0 3 Agfa - Product "Orgacon DRY" (PEDOT / PSS Pellet) 2.0 2.0 2.0 4 ESCC-F300 "(Ag-Cu Flake / D50 = 35 mu m) 20 25 30 5 Everchem Tex - Product "Didim-52" (Anti-Settling agent) 1.0 1.0 1.0 Sum 100.0 100.0 100.0

Examples 7-9. Preparation of Conductive Adhesive Containing Conductive Polymer Solution

The compounds were prepared in the composition ratios shown in Table 5 below and uniformly stirred to prepare the products of Examples 7-9 as conductive adhesives.

No. ingredient Example 7 Example 8 Example 9 One toluene 9.0 4.0 0.0 2 The polymer binder of Production Example 1 50.0 50.0 50.0 3 Soken - Product "AN-SO3-T" (Polyaniline Solution) 20.0 20.0 20.0 4 ESCC-F300 "(Ag-Cu Flake / D50 = 35 mu m) 20 25 30 5 Everchem Tex - Product "Didim-52" (Anti-Settling agent) 1.0 1.0 1.0 Sum 100.0 100.0 100.0

Examples 10-12. Preparation of Conductive Adhesive Containing Conductive Polymer Powder and Conductive Polymer Solution

Compounds were prepared at the composition ratios shown in Table 6 below and uniformly stirred to prepare conductive pastes of Examples 10-12.

No. ingredient Example 10 Example 11 Example 12 One toluene 9.0 4.0 0.0 2 The polymer binder of Production Example 1 50.0 50.0 50.0 3 Agfa - Product "Orgacon DRY" (PEDOT / PSS Pellet) 0.5 0.5 0.5 4 Soken - Product "AN-SO3-T" (Polyaniline Solution) 10.0 10.0 10.0 5 ESCC-F300 "(Ag-Cu Flake / D50 = 35 mu m) 20 25 30 6 Everchem Tex - Product "Didim-52" (Anti-Settling agent) 1.0 1.0 1.0 Sum 101.0 101.0 101.0

Test Example 1. Adhesion Measurement of Conductive Adhesive

After preparing samples of the conductive adhesives of Examples 1-12 and Comparative Example 1-3, the adhesive film for shielding electromagnetic interference was brought into contact with SUS and once again adhered to the copper foil under conditions of 120 DEG C x 0.5 sec. (150 ° C, 37.5Kgf / cm ² ) for 30 minutes and then cured at 160 ° C for 30 minutes to prepare specimens for measuring adhesion. Thereafter, the film was cut into a width of 10 mm and a length of 50 mm, and then subjected to 90 ° peel measurement at a rate of 50 mm / min using a tensile strength tester (Instron 5543) to measure the adhesive strength of the adhesive film.

According to the results shown in the following Table 7, the adhesive strength values according to the contents of the metal powders (20 parts by weight, 25 parts by weight and 30 parts by weight) are only less than 2% in Example 1-12 and Comparative Example 1-3 , And in the case of Example 1-12 in which the conductive polymer was added, the decrease in the adhesive strength was found to be insignificant.

division Adhesion (gf / 10mm) Surface resistance (Ω / □) Example 1 1435 1.95E-01 Example 2 1099 9.08E-02 Example 3 742 6.85E-02 Example 4 1412 8.88E-02 Example 5 1102 6.92E-02 Example 6 745 4.11E-02 Example 7 1435 9.25E-02 Example 8 1099 7.42E-02 Example 9 742 4.99E-02 Example 10 1446 1.46E-01 Example 11 1113 8.25E-02 Example 12 756 5.97E-02 Comparative Example 1 1454 3.72E-01 Comparative Example 2 1111 1.11E-01 Comparative Example 3 750 7.53E-02

Test Example 2. Measurement of Surface Resistance of Conductive Adhesive

After preparing samples of the conductive adhesives of Examples 1-12 and 1-3, the adhesive film for electromagnetic shielding was cut into a size of 50 mm x 50 mm to prepare a test piece for surface resistance measurement. Thereafter, the specimen was measured for 10 V x 10 sec using a low resistance meter (MITSUBISHI MCP-T610), and its surface resistance was measured and described in Table 7 and FIG. 2 above.

According to the results of Table 7, the surface resistance value according to the content of the metal powder is shown in Table 8 below.

Metal powder content Comparative Example powder
1 part by weight powder
2 parts by weight solution
1 part by weight (converted) Powder + solution
1 part by weight (converted) 20 parts by weight 3.72E-01 1.95E-01 8.88E-02 9.25E-02 1.46E-01 25 parts by weight 1.11E-01 9.08E-02 6.92E-02 7.42E-02 8.25E-02 30 parts by weight 7.53E-02 6.85E-02 4.11E-02 4.99E-02 5.97E-02

According to the results of Table 8, it was found that the surface resistance values of Examples 1, 4, 7, and 10 were relatively lower than the surface resistance value of Comparative Example 1 when the metal powder content was 20 parts by weight, It was found that the surface resistance value was reduced by about 50% or more. In particular, in the case of Example 7 using the conductive polymer solution, it was found that the surface resistance was reduced by about 75%. Therefore, it was found that the conductivity enhancing effect was the best when the conductive polymer solution was used.

However, when the amount of metal powder contained 25 parts by weight and 30 parts by weight of metal powder increased, the degree of improvement of conductivity due to use of the conductive polymer was somewhat decreased. This indicates that the increase of the content of metal powder It is expected that the effect of increasing the conductivity by the use of the conductive polymer is insignificant.

However, in the case of using the conductive polymer solution, the surface resistance value of Comparative Example 3 containing 30 parts by weight of the metal powder and the surface resistance value of Example 7 containing 20 parts by weight of the metal powder are similar, The amount of the metal powder to be used can be reduced by about 30%.

On the other hand, the present invention is the result of research carried out by the research support project (No. C0006024) supported by the Small and Medium Business Administration,

Claims (10)

A conductive adhesive comprising a metal powder, a conductive polymer, and a polymeric binder,
Wherein the metal powder is one kind of compound selected from gold, silver, copper, nickel, indium, tin, lead and bismuth or a mixture of two or more kinds thereof or an alloy thereof,
The conductive polymer may be a conductive polymer resin solution; And a conductive polymer composite of a core-shell structure having a carbon core coated with a conductive polymer resin. delete The method according to claim 1,
The conductive polymer resin may be at least one selected from the group consisting of polypyrrole, polythiophene, polyaniline, polyacetylene, polyphenylene sulfide, polyphenylene vinylene, polyindole, Wherein the conductive adhesive is at least one compound selected from the group consisting of polycarbazole, polyazulene, polyazepine, polyfluorene, polynaphthalene, and polyethylene dioxythiophene, or a mixture of two or more thereof. delete The method according to claim 1,
Wherein the polymeric binder is at least one compound selected from an acrylate resin, an epoxy resin, a polyester, a polyurethane, a polycarbonate, a polyamide, a polyimide, and a polyether or a mixture of two or more thereof. A conductive adhesive film comprising a conductive adhesive layer comprising a metal powder, a conductive polymer, and a polymeric binder,
Wherein the metal powder is one kind of compound selected from gold, silver, copper, nickel, indium, tin, lead and bismuth or a mixture of two or more kinds thereof or an alloy thereof,
The conductive polymer may be a conductive polymer resin solution; And a conductive polymer composite of a core-shell structure having a carbon core coated with a conductive polymer resin. delete The method according to claim 6,
The conductive polymer resin may be at least one selected from the group consisting of polypyrrole, polythiophene, polyaniline, polyacetylene, polyphenylene sulfide, polyphenylene vinylene, polyindole, Wherein the conductive adhesive film is at least one compound selected from the group consisting of polycarbazole, polyazulene, polyazepine, polyfluorene, polynaphthalene, and polyethylene dioxythiophene, or a mixture of two or more thereof. delete The method according to claim 6,
Wherein the polymeric binder is at least one compound selected from an acrylate resin, an epoxy resin, a polyester, a polyurethane, a polycarbonate, a polyamide, a polyimide, and a polyether or a mixture of two or more thereof.

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