JP2002008438A - Fibrous electrical conductive filler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrical conductive filler that has good dispersibility into resin and good corrosion resistance, and increases electrical conductivity in low cost. SOLUTION: This fibrous electrical conductive filler is formed by covering surfaces of short fibrous filler substrate particles made of non-electrical conductive substance of specific gravity less than 3.0 with copper alloy film of 10-30 parts by mass based on the filler substrate particles of 100 parts by mass. As a substrate, in particular, middle fibers composed of glass short fibers of fiber diameter of 5-40 μm and fiber length of 20-400 μm (wherein, fiber length >=2x fiber diameter) and chopped strands composed of glass short fibers of fiber diameter of 5-40 μm and fiber length of 1-60 mm and the like are used. As copper alloy for covering, copper-zinc alloys, copper-nickel alloys, copper-nickel- zinc alloys and silver solder and the like are used. As covering method, physical vapor deposition method by-sputtering method is suitable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive filler for use in paints, plastic molded articles, plastic films and the like (hereinafter collectively referred to as an EMI shielding composition) for EMI shielding or antistatic. is there.

[0002]

2. Description of the Related Art In general, an EMI shielding composition comprises a conductive powder and a resin binder or a solvent. As the conductive powder, metal powders such as Ag, Cu, Al, and Ni are well known, and the same amount as the resin component is mixed. But Ag
Are expensive, Cu and Al are easily oxidized, and a change with time in conductivity is recognized. Ni has a disadvantage that it has a large specific gravity and easily sediments in paints and resins.

Therefore, various fillers having a metal coating layer formed on the surface of mica or glass beads instead of these metal powders have been developed. For example, electroless Ag-plated mica (JP-A-54-87674). , Electroless Ni-P plated mica (JP-A-63-54316), electroless Ag, Cu or Ni-P
Plated glass beads (JP-A-63-317541) and Au sputter-coated glass powder (JP-A-56-130469) are known.

[0004] The advantages of these fillers are that the conductivity of the powder itself is inferior to that of the metal powder, that the specific gravity is smaller than that of the metal powder, so that the powder is relatively unlikely to settle even in paint, and that flake-like mica or It has been evaluated that glass beads and the like are more excellent in dispersibility than metal powder.

[0005] On the other hand, however, these metal-coated fillers require a metal coating amount of the base material in order to secure sufficient conductivity.
At present, the amount must be as high as 50 to 60% by mass with respect to 100 parts by mass, which not only increases the manufacturing cost but also increases the specific gravity of the particles and uses mica and glass beads. The advantage of the method is diminished. In addition, those having a film mainly composed of Au increase the material cost,
Those having a film such as Cu or Ni-P are not always excellent in corrosion resistance and may be problematic in practical use. Furthermore, in a conductive paint using a flake-like or spherical conductive filler, unless the compounding amount of the conductive filler in the dried coating film is increased to 80% by mass or more, for example, the surface resistance of the coated plate is 1Ω / cm ² or less. It is said that it is difficult to stably obtain such good conductivity. Such addition of a large amount of the conductive filler not only causes an increase in cost but also is not preferable in sufficiently securing the original properties of the paint (coating film adhesion and other properties other than conductivity). Therefore, development of a conductive filler which is an inexpensive and improved product and which can impart sufficient conductivity to the EMI shielding composition with a smaller amount of use has been desired.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks of the conventional metal-coated filler.
In other words, the filler that greatly reduced the metal coverage
While minimizing the increase in the specific gravity of the filler and further improving the effect of suppressing sedimentation in paint, the conductivity is set to a high level equal to or higher than conventional products, without using expensive Au, Ag is not used or the amount used is reduced as much as possible to reduce material costs.At the same time, corrosion resistance is set to a high level that can withstand practical use in various applications. An object of the present invention is to provide a conductive filler having a shape capable of imparting sufficient conductivity to an EMI shielding composition even in a small amount.

[0007]

Means for Solving the Problems The inventors made various metal-coated fillers and proceeded with detailed studies. as a result,
It has been found that high conductivity can be achieved in the EMI shielding composition if the surface of the base particles is coated almost uniformly and continuously even if the amount of metal coating is small. In addition, when the filler base material was examined from the viewpoint of “shape”, when the shape of the short fiber was used, compared to the case of using the flake shape or the spherical shape, the composition for the EMI shielding composition was reduced. It has been found that the effect of imparting conductivity is significantly improved. Then, it was confirmed that the amount of the conductive filler in the EMI shielding composition can be significantly reduced by using the short fiber conductive filler.

[0008] Further, it has been found that by coating an appropriate amount of a commonly available copper alloy with an appropriate amount of a conductive film, material cost reduction and improvement of corrosion resistance can be achieved at the same time. Also, a uniform coating of such an alloy
It was confirmed that the physical vapor deposition method by the sputtering method can be suitably performed. The present invention has been completed based on the above findings.

[0009] That is, the above-mentioned object is achieved by coating the surface of the short fibrous filler base particles made of a non-conductive substance having a specific gravity of 3.0 or less with a copper alloy film of 10 to 30 parts by mass with respect to 100 parts by mass of the filler base particles. This is achieved by the coated fibrous conductive filler.

The filler base particles may have a fiber diameter of 5 to 40.
The use of short fibers having a fiber length of 20 μm and a fiber length of 20 μm to 60 mm (fiber length ≧ 2 × fiber diameter) is provided. In addition, as the short fibers, particularly, a fiber diameter of 5 to 40 μm and a fiber length of 20 to 400 μm
Provided are milled fibers made of glass short fibers (fiber length ≧ 2 × fiber diameter) or chopped strands made of glass short fibers having a fiber diameter of 5 to 40 μm and a fiber length of 1 to 60 mm.

As a copper alloy coated on the surface of the filler base particles, at least 25% by mass of Cu is contained, and the balance is at least 5% by mass of Zn and at least 5% by mass of Ni. Provided are those using Cu-Zn-based alloys, Cu-Ni-based alloys or Cu-Zn-Ni-based alloys containing Further, at least 20% by mass or more of Cu is contained, and 35 to 75%
Cu-Ag-based alloy containing at least 20% by mass of Ag, or a Cu-Ag-Zn-based alloy containing at least 20% by mass of Cu and the balance containing 35-75% by mass of Ag and 5% by mass or more of Zn Provide something using. These Cu-Zn alloys, Cu-Ni alloys, Cu-Zn-Ni alloys, Cu-Ag alloys, and Cu-Ag-Zn alloys are the main elements (Cu, Zn, Ni ,
In addition to Ag), it may contain various elements added to improve various properties of the copper alloy, and impurity elements inevitably mixed in during production.

Further, the present invention provides a copper alloy film formed by a physical vapor deposition method. In addition, the present invention particularly provides a method wherein the physical vapor deposition method is a sputtering method in which coating is performed while forming a fluidized bed of aggregates of short fibrous filler base material particles in a rotating container.

[0013]

DETAILED DESCRIPTION OF THE INVENTION According to the study of the present inventors, it has been found that the effect of imparting conductivity to an EMI shielding composition is significantly improved by making the conductive filler into a short fiber shape. . It is considered that this is because the short fiber form is more likely to come into contact with each other three-dimensionally than the flake form or the spherical form. Therefore, when the short-fiber conductive filler is used, the amount of the conductive filler required for imparting a certain conductivity to the EMI shielding composition can be significantly reduced. For example, in order to obtain conductivity of about 1 Ω / cm ² or less in a dried coating film having a thickness of about 25 μm, in the case of a flake-like or spherical conductive filler, about 80% by mass is usually contained in the coating film.
It is said that it is necessary to mix the above. On the other hand, when using the short fibrous conductive filler according to the present invention,
As will be shown in the examples below, the above conductivity can be sufficiently achieved with a blending of about 50% by mass.

However, simply changing the shape of the conductive filler into a short fiber does not significantly improve the conductivity of the EMI shielding composition. For that purpose, the surface of each filler base particle must be almost uniformly and continuously coated with a conductive material. In other words, if there is an uncoated portion of the conductive material on the surface of the filler base particles, or if the conductive material has a non-uniform and uneven surface with many irregularities, the EMI shielding composition may be used. Has a small effect of imparting conductivity.

In the present invention, a copper alloy is coated as a conductive material as described later. In that case, first, a material having a specific gravity of 3.0 or less must be used as the short fibrous filler base particles. If the specific gravity is larger than the above, the dispersibility in the EMI shielding composition may be deteriorated, for example, the sedimentation in the paint may increase due to the increase in specific gravity due to the coating of the copper alloy. Various substances can be used as long as they have a specific gravity of 3.0 or less, can be produced in the form of short fibers, and can be coated with a copper alloy, and are not particularly limited.

As a result of the study by the inventors, the surface of the short fibrous filler base particles having a specific gravity of 3.0 or less is changed to the filler base particles.
It was found that when covered with 10 to 30 parts by mass of the copper alloy film with respect to 100 parts by mass, the effect of imparting conductivity to the EMI shielding composition was significantly improved. When the coating amount of the copper alloy is less than 10 parts by mass, the effect of imparting conductivity is extremely small. This is probably because the exposed portion of the base material remains on the particle surface. When the coating amount is 10 parts by mass or more, the effect of imparting conductivity rapidly appears. On the other hand, when the coating amount exceeds 30 parts by mass, the conductivity-imparting effect is rapidly deteriorated without being maintained. This is considered to be due to the fact that the larger the amount of coating film, the larger the surface irregularities and the worse the contact between individual particles.

Typical filler base materials suitable for the present invention include short glass fibers, but other short carbon fibers and whiskers such as silicon nitride, alumina and aluminum silicate can also be used. It has also been confirmed that the size of the short fibers can be suitably used over a wide range. Specifically, the fiber diameter is 5 to 40 μm and the fiber length is 20
μm to 60 mm (however, fiber length ≧ 2 × fiber diameter) can be applied, preferably fiber diameter 10 to 30 μm, fiber length 30 μm
It is preferable to use one having a fiber length of 5050 mm (fiber length ≧ 2 × fiber diameter). It is more desirable that “fiber length ≧ 10 × fiber diameter”.

The short glass fiber is used as a reinforcing material of a thermoplastic resin such as an engineering plastic, a premix base material of a thermosetting resin, and a glass paper for a heat insulating material, a soundproofing material, a filtering material, and the like. It is used and is already produced in large quantities industrially. It is preferable to use such easily available short glass fibers because the cost can be reduced. However, no example has been found in which this is used as a conductive filler base material. The reason is that it is hard to say that a technique for forming a thin and uniform conductive film on such fibrous particles has generally been established, and therefore, in general, an environment in which even an experimental sample can be sufficiently prepared is established. It is possible that they did not. The present inventors have overcome this point by utilizing a physical vapor deposition method described later.

Short glass fibers produced industrially include milled fibers and chopped strands. In the present invention, fiber diameter 5 ~ 40μm, fiber length 20 ~ 400μm
(However, milled fiber consisting of short glass fiber with fiber length ≧ 2 × fiber diameter), fiber diameter 5 to 40 μm, fiber length 1 to 60 m
Chopped strands made of m glass short fibers can be used. Especially, the fiber diameter is 10 ~ 30μm, the fiber length is 30 ~ 3
Milled fibers made of short glass fibers having a fiber length of 00 μm (fiber length ≧ 2 × fiber diameter) and chopped strands made of short glass fibers having a fiber diameter of 10 to 30 μm and a fiber length of 1 to 50 mm have been produced in large numbers. Another advantage of the present invention is that various mass-produced products can be used. The composition of these mass-produced products is mostly silicate-based, the main component being SiO ₂ , and also contains Na ₂ O, CaO, Al ₂ O ₃ , B ₂ O _{3 and the} like.

In the present invention, a copper alloy is used as a coating material because:
Mainly for the following reasons. i) be a good conductive substance,
ii) It has excellent practical corrosion resistance in the environment where the EMI shielding composition is used, and iii) Inexpensive materials are easily available. Preferred copper alloy materials satisfying such conditions include the following. Contains at least 25% by mass of Cu and the remaining 5% by mass
A Cu-Zn alloy containing the above Zn. A typical example of this system is brass. Contains at least 25% by mass of Cu and the remaining 5% by mass
A Cu-Ni-based alloy containing the above Ni. Representative examples of this system include white copper (cupronickel) and monel metal. Contains at least 25% by mass of Cu and the remaining 5% by mass
Cu-Zn-Ni containing above Zn and 5% by mass or more of Ni
System alloy. A typical example of this system is Western white. Contains at least 20% by mass or more of Cu, and
Cu-Ag-based alloy containing at least 20% by mass of Ag, or a Cu-Ag-Zn-based alloy containing at least 20% by mass of Cu and the balance containing 35-75% by mass of Ag and 5% by mass or more of Zn . Silver wax belongs to these systems. In addition, various copper alloys including Co, Cr, Fe, Pb, B, and P can be used. However, those containing Al or Si are not suitable because an insulating oxide film such as Al ₂ O ₃ or SiO ₂ is formed on the outermost surface of the coating layer.

As a method of coating a metal on the surface of a powder, an electroless Cu plating method or an electroless Ni-P plating method is generally widely used. However, it is impossible to form a film of the copper alloy composition by these methods. On the other hand, a physical vapor deposition method is known as a method for forming an alloy film having an arbitrary composition on a powder surface. In particular, according to the sputtering method introduced by the present inventors in JP-A-2-153068, a substantially uniform metal coating layer can be continuously formed on the surface of each powder particle. In this method, a powder is placed in a rotating container (barrel), a fluidized bed of the powder is formed with stirring, and the sputtered coated metal is caused to collide with the powder particles forming the fluidized bed, thereby forming an individual powder. A metal coating layer is formed on the surface of the powder particles.

However, the filler base material to be used in the present invention is of a short fiber type, and its length is intended to cover up to about 60 mm. In addition, it is not always possible to identify the powder. As a matter of fact, there is no report that the sputtering method disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 2-153068 has been applied to the short fibrous filler as in the present invention. Then, the inventors repeated various experiments. As a result, it was confirmed that the sputtering method disclosed in JP-A-2-153068 can be sufficiently applied to the short fibrous filler of the present invention.

When an alloy film having a constant composition is formed by a sputtering method, a method of using a target as described below is generally known. a) A target composed of multiple crystal phases that are not single phase but have the same average composition as the alloy film to be formed,
A method created and used by sintering or melting. b) A method using a combination target in which another alloying element is embedded in a metal plate composed mainly of an alloy film to be formed. c) A method of forming a film having a desired alloy composition by combining a plurality of single metal targets. These are alloy solid solution phases that cannot be obtained by ordinary metallurgical techniques,
This is a very effective means for obtaining an alloy that is extremely difficult to manufacture. These means can be used in the present invention. However, in the present invention, it is possible to reduce the cost by using corrosion-resistant materials such as brass, bronze, nickel silver, silver braze, etc., which are readily available in the market (commonly obtained by ordinary metallurgy) as raw materials. This is advantageous from a viewpoint. Although these materials also have a composition region exhibiting a multi-phase structure, many are single-phase, so when using a single-phase material, the above a) to
Regardless of the means of c), a copper alloy having a target composition can be used as a target as it is.

Although a vacuum deposition method can be used, C
Since the melting points and vapor pressures of the respective metal elements such as u, Zn, Ni, and Ag are greatly different from each other, it is not always easy to control the composition of the alloy film constant.

One of the important findings that led to the present invention is that, according to the above-mentioned sputtering method, a filler exhibiting excellent conductivity can be produced with a much smaller amount of metal coating than in an electroless plating method or the like. It is the point that I discovered that I could do it.

That is, in the case of the electroless plating method, the surface of the filler base material particles is previously activated with Pd or the like as a pretreatment, and the portion where the Pd adheres is formed with a metal film when the electroless plating proceeds. It is said to be the point of origin of the nucleus. Since the adhesion of Pd is based on a mere adsorption phenomenon, the adhesion density is not so high. For this reason,
In order to continuously cover the entire substrate particle surface with plating metal that grows around each nucleus (thickest at the nucleus position and thinner at the periphery), the nucleus density is not high,
As a result, a considerable amount of plating is required. In addition, the surface irregularities increase.

On the other hand, in the case of the sputtering method,
Since the phenomenon in which metal atoms excited to the plasma state collide with the surface of the base material particles at high speed is repeated, nucleation points at the time of forming the metal film become extremely dense. For this reason, it is considered that the entire surface of the base particles is covered early even with a small amount of metal adhesion. In this case, surface irregularities are also reduced.

Further, when a single metal is coated by an electroless plating method or the like, the crystal tends to be coarse during the generation and growth of nuclei, whereas a different metal having a different crystal structure is used in the sputtering method. As a result of various investigations on the conditions of the sputtering method, focusing on the fact that crystals tend to be refined during the generation and growth of nuclei when coating as an alloy, the entire surface of the base particles was coated with a smaller amount of metal. It is now possible to cover. For example, in the electroless plating method,
If it was difficult to form a continuous film covering the entire surface of the substrate without coating a large amount of metal of 50 parts by mass or more with respect to parts by mass, a continuous film was formed with a small amount of metal of 30 parts by mass or less according to the sputtering method. Can be formed.

An example of the specific gravity of the product of the present invention is as follows. For example, a nickel white having a specific gravity of 8.6 is added to 100 parts by mass of a glass short fiber having a specific gravity of 2.55.
The specific gravity of the product of the present invention coated with 10 to 30 parts by mass is 3.2 to 4.4. These are Cu specific gravity 8.96, Ni specific gravity 8.90, Ag specific gravity 1
Extremely lighter than 0.5. Furthermore, the specific gravity is considerably lighter than that of the product disclosed in JP-A-63-54316 (when mica having a specific gravity of 2.8 is coated with 50% by mass of electroless Ni-P plating having a specific gravity of 8.9). Therefore, in the product of the present invention, the sedimentation in the paint is more unlikely to occur.

After the surface of the short glass fiber is coated with a copper alloy, a surface treatment such as a silane coupling treatment or a titanate coupling treatment may be performed to improve dispersibility in the paint.

[0031]

EXAMPLES Examples of the present invention and comparative examples are shown below.
The results are summarized in Table 1 below. The numbers of the examples and comparative examples correspond to the numbers in Table 1.

[Examples 1 to 3] Milled fiber having an average fiber diameter of 10 μm and an average fiber length of 30 μm (MF06 manufactured by Asahi Fiber Glass Co., Ltd.) was used by using a powder sputtering apparatus introduced in JP-A-2-153068. Series) on the surface of 100g,
Nickel white (JIS 1 class, 73% by mass Cu-18% by mass Ni-9% by mass Z
n) coated. The coating amount of nickel white was 10 parts by mass (Example 1), 20 parts by mass (Example 2), and 30 parts by mass (Example 3) based on 100 parts by mass of the milled fiber.

An acrylic paint base (Kansai Paint Co., Ltd.) was placed in an 800 ml stainless steel container with 100 g of each sample obtained.
250 g of No. 2026 (containing 40% by mass of resin) was dispersed and mixed for 1 hour while rotating the stirring blade at 2000 rpm. Using a doctor blade on a 1.0 mm thick transparent acrylic plate, the resulting acrylic paint has a dry coating thickness of about 25 μm.
And dried at room temperature. As a result of measuring the surface electric resistance of the coated plate after drying, the surface resistance was 1 Ω / cm ² or less, indicating good conductivity.

[Examples 4 to 6] Using the same apparatus and method as in Examples 1 to 3, a surface of 100 g of milled fiber having an average fiber diameter of 13 μm and an average fiber length of 300 μm was coated with brass (60 mass% Cu-40 mass%). Zn). The coating amount of brass was 10 parts by mass per 100 parts by mass of the milled fiber (Example 4), 20 parts by mass.
Parts by mass (Example 5) and 30 parts by mass (Example 6) were used. Using 100 g of each obtained sample, an acrylic coated plate having a dry coating thickness of about 25 μm was prepared in the same manner as in Examples 1 to 3. As a result of measuring the surface electric resistance of the coated plate after drying, the surface resistance was 1 Ω / cm ² or less, indicating good conductivity.

[Examples 7 to 9] Using the same apparatus and method as in Examples 1 to 3, the surface of 100 g of chopped strand (CS series, manufactured by Asahi Fiber Glass Co., Ltd.) having an average fiber diameter of 30 μm and an average fiber length of 50 mm. In addition, silver braze (50 mass% Ag-35 mass%
Cu-15% by mass Zn). The coating amount of the silver solder was 10 parts by mass (Example 7), 20 parts by mass (Example 8), and 30 parts by mass (Example 9) based on 100 parts by mass of the chopped strand. Examples 1 to 10 using 100 g of each obtained sample
In the same manner as in Example 3, an acrylic coated plate having a dry coating thickness of about 25 μm was prepared. As a result of measuring the surface electric resistance of the coated plate after drying, the surface resistance was 1 Ω / cm ² or less, indicating good conductivity.

In the above embodiment, 100 g of the invention product (filler after coating) was applied to 250 g of paint (of which 40
%), The filler content in the dry coating film was calculated to be 100 g / (250 g × 40/100 + 100 g).
g) × 100 = 50% by mass. In a conductive paint using a flake or spherical conductive filler, the surface resistance is usually 1 Ω / cm ² unless the compounding ratio of the conductive filler is increased to 80% by mass or more.
Considering that it is difficult to stably obtain the following conductivity, it can be seen that when the product of the present invention is used, the amount of conductive filler added can be significantly reduced.

[Comparative Examples 1 and 2] Using the same kind of milled fiber and nickel silver as in Examples 1 to 3, the same acrylic coated plate was produced by the same apparatus and method. However, the coating amount of nickel white was 5 parts by mass (Comparative Example 1) and 40 parts by mass (Comparative Example 2) with respect to 100 parts by mass of the milled fiber. As a result of measuring the surface electric resistance of the coated plate after drying, good conductivity was not obtained in those examples in which the coating amount of the copper alloy was out of the range specified in the present invention.

[Comparative Examples 3 and 4] Using the same kind of milled fiber and brass as in Examples 4 to 6, similar acrylic coated plates were produced using the same apparatus and method. However, the coating amount of brass was 5 parts by mass (Comparative Example 3) and 40 parts by mass (Comparative Example 4) with respect to 100 parts by mass of the milled fiber. As a result of measuring the surface electric resistance of the coated plate after drying, good conductivity was not obtained in those examples in which the coating amount of the copper alloy was out of the range specified in the present invention.

Comparative Examples 5 and 6 Using the same type of chopped strands and silver solder as in Examples 7 to 9, similar acrylic coated plates were produced using the same apparatus and method. However,
The coating amount of the silver solder was 5 parts by mass (Comparative Example 5) and 40 parts by mass (Comparative Example 6) with respect to 100 parts by mass of the chopped strand. As a result of measuring the surface electric resistance of the coated plate after drying, good conductivity was not obtained in those examples in which the coating amount of the copper alloy was out of the range specified in the present invention.

[0040]

[Table 1]

[0041]

The conductive filler according to the present invention has the following advantages. Since the coating amount of the conductive film is small, an increase in the specific gravity of the filler particles due to the coating is suppressed, and as a result, the dispersibility in the EMI shielding composition is improved, for example, sedimentation in the paint is less likely to occur. By making the filler into a short fiber shape, the effect of imparting conductivity to the EMI shielding composition is significantly improved, so that the amount of the conductive filler required to impart a certain conductivity can be significantly reduced. Since a copper alloy is used as the conductive coating material, practically sufficient corrosion resistance can be obtained at low cost. As the raw material of the product of the present invention, a short fiber material mass-produced for another purpose and a commercially available copper alloy material can be used, so that the present invention is relatively easy to implement and the material cost can be reduced.

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (reference) C09D 5/24 C09D 5/24 201/00 201/00 F term (reference) 4J037 AA08 CA03 EE03 FF11 4J038 EA011 HA066 HA486 KA08 KA15 KA19 NA20 5G301 DA06 DA10 DA15 DA29 DD02 DE03

Claims (8)

[Claims] 1. The surface of short fibrous filler base particles made of a non-conductive substance having a specific gravity of 3.0 or less is coated with a copper alloy film of 10 to 30 parts by mass with respect to 100 parts by mass of the filler base particles. Fibrous conductive filler. 2. The short fibrous filler base particles made of a non-conductive substance have a fiber diameter of 5 to 40 μm and a fiber length of 20 μm to 60 mm (fiber length ≧ 2 × fiber diameter). Fibrous conductive filler. 3. The short fibrous filler base particles made of a non-conductive material are milled fibers made of glass short fibers having a fiber diameter of 5 to 40 μm and a fiber length of 20 to 400 μm (fiber length ≧ 2 × fiber diameter). The fibrous conductive filler according to claim 1. 4. The fibrous conductive filler according to claim 1, wherein the short fibrous filler base particles made of a non-conductive substance are chopped strands made of short glass fibers having a fiber diameter of 5 to 40 μm and a fiber length of 1 to 60 mm. . 5. A copper alloy comprising at least 25% by mass of Cu and at least 5% by mass of Zn and at least 5% by mass of Ni in a copper alloy constituting the film. The fibrous conductive filler according to claim 1, which is a Zn-based alloy, a Cu-Ni-based alloy, or a Cu-Zn-Ni-based alloy. 6. A Cu-Ag alloy containing at least 20% by mass of Cu and at least 35-75% by mass of Ag, or at least 20% by mass of Cu. And the balance is 35-75% by mass of Ag and 5% by mass or more of Z
The fibrous conductive filler according to any one of claims 1 to 4, which is a Cu-Ag-Zn-based alloy containing n. 7. The fibrous conductive filler according to claim 1, wherein the copper alloy film is coated by a physical vapor deposition method. 8. The fibrous conductive filler according to claim 7, wherein the physical vapor deposition method is a sputtering method in which coating is performed while forming a fluidized layer of the short fibrous filler base material particle aggregate in a rotating container.