JP2001200225A - Electroconductive resin composition for adhesion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electroconductive resin composition for adhesion which has very good electroconductivity and adhesive properties. SOLUTION: There is provided an electroconductive resin composition for adhesion formed by mixing (a) a thermoplastic resin or a thermoplastic elastomer or a mixture thereof as a substrate, (b) a low-melting metal having a melting point of 300 deg.C or below, and (c) a metal powder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming conductive adherends between metallic materials such as copper and stainless steel.
The present invention relates to a hot-melt type adhesive resin composition capable of firmly joining while maintaining conductivity.

[0002]

2. Description of the Related Art In recent years, a resin composition capable of firmly joining conductive materials while maintaining conductivity has been required. 2. Description of the Related Art Due to technical progress in the electronics field, modularization of electronic components has been promoted, and in such a field, a conductive resin adhesive is indispensable. However, although there is a demand for a conductive material, for example, a hot-melt type bonding resin composition capable of bonding a metal material such as a stainless steel material and a copper material, one having a sufficient adhesiveness and conductivity is commercially available. There is no present.

[0003]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a hot-melt type adhesive resin composition capable of firmly joining a conductive material, particularly a metal material, while maintaining the conductivity. That is the task.

[0004]

The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, completed the present invention. That is, the gist of the present invention is that (a) a thermoplastic resin or a thermoplastic elastomer and a mixture thereof are used as a substrate, (b) a low-melting-point metal having a melting point of 300 ° C. or less, and (c) a metal powder. Resin composition for adhesion.

[0005] Preferred embodiments of the present invention include the following. (A) The thermoplastic resin or the thermoplastic elastomer and the mixture thereof are 20 to 80% by volume of the adhesive resin composition, and the proportion of the metal powder (c) in the metal component combining (b) and (c) is The adhesive resin composition described above, which is in a range of 10 to 30% by volume. The low melting point metal of the component (b) is Pb / Sn, Pb / Sn /
Bi, Pb / Sn / Ag, Pb / Ag, Sn / Ag, S
The above adhesive resin composition comprising a low melting point alloy selected from n / Bi, Sn / Cu and Sn / Zn. The metal powder of the component (c) is composed of Cu, Ni, Al, Cr and an alloy powder thereof, and has an average particle size of 1 to 50 μm.
The adhesive resin composition described above, wherein (A) The above-mentioned conductive resin composition for adhesion, wherein a part of a thermoplastic resin or a thermoplastic elastomer and a mixture thereof is acid-modified and contains a carboxyl group.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The conductive resin composition for adhesion of the present invention is characterized in that the material is (a)
A thermoplastic resin or a thermoplastic elastomer and a mixture thereof, (b) a low melting point metal having a melting point of 300 ° C. or less,
And (c) a mixture of metal powders (hereinafter, referred to as “mixture”). By using a specific combination of a thermoplastic resin or a thermoplastic elastomer and a mixture thereof and a metal component for imparting conductivity, other properties such as extremely high conductivity and adhesion can be imparted in a well-balanced manner. It has been found that the mixed material contains (a) a thermoplastic resin or a thermoplastic elastomer and a mixture thereof in the range of 20 to 80% by volume, preferably 40 to 60% by volume of the whole composition. Is preferred. If the content of the resin component exceeds 80% by volume, conductivity tends to be hardly exhibited. If the content is less than 20% by volume, the fluidity is reduced and the wettability required for adhesion is poor.

Further, in order to improve the adhesive strength between a thermoplastic resin or a thermoplastic elastomer and a mixture thereof and a low melting point metal and to firmly express the adhesiveness to an adherend, the thermoplastic resin or the thermoplastic elastomer is used. It is necessary to modify a part with an organic unsaturated carboxylic acid having 3 to 10 carbon atoms. As the organic unsaturated carboxylic acid, for example, acrylic acid, maleic acid, methacrylic acid, fumaric acid,
Itaconic acid and the like are preferred. The metal powder (c) acts as a dispersing aid for the low-melting metal, and the proportion of the metal powder (c) in the metal component is 10 to 30% by volume, preferably 15 to 25% by volume.
It is preferable to set it in the range of volume%. If the content is less than 10% by volume, the dispersion state is deteriorated. If the content exceeds 30% by volume, the fluidity tends to be reduced, the embrittlement is liable to occur, and the conductivity tends to be reduced.

As the thermoplastic resin (a) used for the mixture, polyolefins such as EVA, PP and PE, nylon, PET, polyurethane and the like can be used.
Similarly, various types of thermoplastic elastomers such as olefin-based, styrene-based, PVC-based, urethane-based, ester-based, and amide-based thermoplastic elastomers can be used.

Various kinds of low melting point metals having a melting point of 300 ° C. or less can be used. The melting point can be measured by the differential scanning calorimetry (DSC).
The measurement may be performed according to C), and there is a problem that a metal having a melting point exceeding 300 ° C. has poor moldability. Specifically, P
b / Sn, Pb / Sn / Bi, Pb / Sn / Ag, Pb
/ Ag, Sn / Ag, Sn / Bi, Sn / Cu, Sn /
A solder alloy selected from Zn-based can be suitably used.
The metal powder of the component (c) serves as a dispersing aid for the low-melting-point metal, and Cu, Ni, Al, Cr and alloy powders thereof can be suitably used, and the average particle size is 1 to 50 μm.
Are preferred. The average particle diameter is a number average particle diameter obtained by photographing a sample with a transmission electron microscope and obtaining the photograph. When the average particle size is less than 1 μm, handling during mixing is difficult, and when the average particle size exceeds 50 μm, the dispersibility tends to decrease.

The adhesive conductive resin composition of the present invention is prepared by kneading a mixture of the above-mentioned components using a kneader such as a kneader or a twin-screw extruder at a predetermined temperature. An applicator, a hot melt coater, a slit coater, and a hot melt roll coater can be applied and used. Further, a film-like or web-like dispersion-like material can be used by placing it on an adherend. In kneading, (c) a temperature at which the low-melting metal is in a semi-molten state is preferable, and an appropriate metal composition is selected according to the melting temperature of the thermoplastic resin or the thermoplastic elastomer serving as a matrix. It is necessary to appropriately select the addition ratio of the copper powder, the nickel powder, and the like to be used. The kneaded material obtained by the above method is formed into pellets, powders, sheets, and dispersions according to the purpose of use.

As described above, the conductive resin composition for adhesion of the present invention has a very high conductivity because the thermoplastic resin or the thermoplastic elastomer and the mixture thereof contain the low melting point metal. On the other hand, since a part of the resin has a strong adhesive strength due to acid transformation, it can be strongly bonded in the electronics field while maintaining the conductivity between conductive materials, especially metal materials. It is applicable as a hot-melt type adhesive resin composition that can be used.

[0012]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. Santoprene 8211-35 / AES Japan as a thermoplastic elastomer,
Acid-modified polyolefin ("Adtex ER320P" manufactured by Nippon Polyolefin Co., Ltd.) is used as the thermoplastic resin, and lead-free solder (Sn-4Cu-) is used as the low-melting metal.
2Ni melting point: solidus line 225 ° C-liquidus line 480 ° C), and copper powder having an average particle size of 10 µm was used as the metal powder. Physical mixing of each raw material powder in advance (thermoplastic elastomer 4
0 volume%, acid-modified polyolefin 10 volume%, low melting point metal 45 volume%, metal powder 5 volume%), twin screw extruder ("2
D25-S "(manufactured by Toyo Seiki Co., Ltd.).

The kneading conditions are as follows. Cylinder temperature: 200 ° C Screw rotation speed: 20r. p. m.

[0014] The kneaded adhesive resin composition is placed on a glass plate.
Coated to 0mm width x 80mm length, cooled and solidified, JIS
The resistance of the adhesive resin composition was measured by a four probe method according to K7194, and the surface resistance was calculated. The surface resistance was 3.5 × 10 ⁻⁴ Ω / cm ² and was excellent in conductivity.

Next, according to JIS K6850, 2
The above kneaded adhesive resin composition was applied to an end of a copper foil having a width of 5 mm × 100 mm × 100 μm in thickness of 12.5 mm and solidified by cooling to obtain a hot melt type conductive adhesive resin. A copper foil of the same size was overlaid on the portion where the adhesive was applied, and heated and pressed at 200 ° C. and 2.0 MPa for 10 seconds to prepare a sample, and the shear bond strength was measured. As a result, the measured value was 8.3 MPa, and the adhesive strength was also excellent.
SUTEC / EMI G710PSE which is a metal fiber-filled conductive resin in which a finely cut SUS304 fiber is filled into a polystyrene-based elastomer as a comparative example)
(Kawatetsu Techno Research) was used to perform the same measurement as above. As a result, the surface resistance was 1.0 × 10 ⁰ Ω /
cm ² , the shear adhesive strength was 1.0 MPa, and both the conductivity and the adhesive strength were inferior to those of the examples.

[0016]

As described above, the conductive resin composition for bonding of the present invention has a very high conductivity because the thermoplastic resin or the thermoplastic elastomer and the mixture thereof contain a low melting point metal. On the other hand, since a part of the resin is acid-denatured and has strong adhesive strength, it is necessary to firmly join conductive materials in the field of electronics, especially metal materials while maintaining conductivity. It is applicable as a hot-melt type adhesive resin composition that can be used.

Claims (5)

[Claims] 1. Adhesion obtained by mixing (a) a thermoplastic resin or a thermoplastic elastomer and a mixture thereof as a substrate, (b) a low-melting metal having a melting point of 300 ° C. or less, and (c) a metal powder. Conductive resin composition. 2. (a) 20-80% by volume of the thermoplastic resin or thermoplastic elastomer and a mixture thereof in the conductive resin composition for bonding, and (c) in the metal component combining (b) and (c). ) The ratio of the metal powder is 10 to 30% by volume
The conductive resin composition for adhesion according to claim 1, wherein 3. The low melting point metal of component (b) is Pb / S
n, Pb / Sn / Bi, Pb / Sn / Ag, Pb / A
g, Sn / Ag, Sn / Bi, Sn / Cu, Sn / Zn
The conductive resin composition for adhesion according to claim 1, comprising a low melting point alloy selected from a series. 4. The metal powder of component (d) is Cu, Ni, A
2. The powder of claim 1, wherein said powder is made of l, Cr or an alloy powder thereof, and has an average particle diameter in the range of 1 to 50 μm.
4. The conductive resin composition for bonding according to any one of items 3 to 3. 5. The adhesive conductive material according to claim 1, wherein (a) a part of the thermoplastic resin or the thermoplastic elastomer and a mixture thereof is acid-modified and contains a carboxyl group. Resin composition.