JP2022134303A - Manufacturing method of conductive film - Google Patents

Abstract

To provide a manufacturing method of a conductive film capable of manufacturing a conductive film having a desired electric resistance value.SOLUTION: A method for manufacturing a conductive film is a method for manufacturing a conductive film having a layer formed of a resin composition containing a polymer material and a conductive filler. This method for manufacturing a conductive film includes a step of producing a conductive film using a resin composition, and a step of forming a metal thin film on the above layer of the conductive film in multiple steps to adjust the electrical resistance value of the conductive film.SELECTED DRAWING: Figure 3

Description

TECHNICAL FIELD The present invention relates to a method for producing a conductive film, and more particularly to a method for producing a conductive film having a layer formed from a resin composition containing a polymeric material and a conductive filler.

Japanese Patent Laying-Open No. 2014-91248 (Patent Document 1) discloses a method for producing a conductive film. This conductive film is produced by using a resin composition containing a thermoplastic resin and a conductive filler. In this manufacturing method, the conductive film is manufactured by conveying the resin composition extruded from the T-die backward by rollers.

JP 2014-91248 A

For example, in a conductive film provided with a layer formed of a resin composition containing a polymer material and a conductive filler, it is required that the electrical resistance value of the conductive film can be adjusted to a desired value. . However, Patent Document 1 does not disclose a technique for adjusting the electrical resistance value of the conductive film to a desired value.

The present invention has been made to solve such problems, and its object is to provide a method for producing a conductive film capable of producing a conductive film having a desired electrical resistance value. .

A method for producing a conductive film according to the present invention is a method for producing a conductive film having a layer formed of a resin composition containing a polymeric material and a conductive filler. This method for producing a conductive film includes the steps of producing a conductive film using a resin composition, and forming a metal thin film on the above-mentioned layers of the conductive film in a plurality of steps to reduce the electrical resistance of the conductive film. and adjusting the value.

The present inventors (and others) have found that the electrical resistance value of the conductive film can be adjusted by changing the number of times the metal thin film is formed on the layer containing the conductive filler. In the method for producing a conductive film according to the present invention, a thin metal film is formed on the layer of the conductive film in multiple steps. Therefore, according to this method for producing a conductive film, a conductive film having a desired electrical resistance value can be produced.

The method for producing a conductive film further includes the step of determining the number of times the metal thin film is formed on the layer based on a target value for the electrical resistance of the conductive film, and in the step of adjusting the electrical resistance, , a metal thin film may be formed on the layer by the determined number of times.

In the above method for producing a conductive film, in the step of adjusting the electrical resistance value, the volume resistivity of the conductive film may be adjusted.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the electrically conductive film which can manufacture the electrically conductive film which has a desired electrical resistance value can be provided.

It is a figure which shows a film manufacturing apparatus typically. It is a figure which shows a metal thin film formation apparatus typically. It is a flowchart which shows an example of the manufacturing procedure of a conductive film. 4 is a flow chart showing another example of a procedure for manufacturing a conductive film;

DETAILED DESCRIPTION OF THE INVENTION Embodiments according to one aspect of the present invention (hereinafter also referred to as "present embodiments") will be described in detail below with reference to the drawings. The same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated. Moreover, the present embodiment described below is merely an example of the present invention in every respect. Various improvements and modifications can be made to the present embodiment within the scope of the present invention. That is, in carrying out the present invention, a specific configuration can be appropriately adopted according to the embodiment.

[1. Manufacturing equipment for conductive film]
FIG. 1 is a diagram schematically showing a film manufacturing apparatus 10 used in the method for manufacturing a conductive film according to this embodiment. As shown in FIG. 1, the film manufacturing apparatus 10 includes a T-die 100, a cast roll 200, a touch roll 300, and a take-up roll 400. As shown in FIG.

The T-die 100 is configured to melt-extrude the resin composition C1. The resin composition C1 contains a polymer material and a conductive metal filler. In the film manufacturing apparatus 10, a conductive film C2 is manufactured based on the resin composition C1. The conductive film C2 is subjected to further processing described later, and is used as, for example, a charging film or a neutralization film for copiers, printers, etc., and various functional films for other electric/electronic devices and parts. The resin composition C1 may contain other conductive fillers such as carbon black and carbon nanotubes instead of the conductive metal fillers.

Polyolefin resins (homopolymers and copolymers) such as polypropylene (PP) or polyethylene (PE) may be used as the polymer material. Examples of polymer materials include tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and ethylene-tetrafluoroethylene copolymer (ETFE). Alternatively, fluorine-based copolymers such as tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymer (EPE), polyester copolymers such as polyetherester, or polyetheramide or polyetheresteramide A polyamide-based copolymer or the like may also be used. Moreover, as the polymer material, for example, a polymer alloy or a polymer blend of the above-described ones may be used.

Conductive metal fillers include platinum, gold, silver, copper, nickel, titanium and mixtures thereof. That is, the metal filler contained in the resin composition C1 contains at least one metal selected from the group containing platinum, gold, silver, copper, nickel and titanium. Among these, nickel particles are more preferable as the metal filler.

The cast roll 200 is configured to cool the resin composition C1 extruded by the T-die 100 and send it downstream. The touch roll 300 is configured to press the resin composition C1 extruded by the T-die 100 toward the cast roll 200 and send it downstream. That is, the resin composition C1 is sandwiched between the cast roll 200 and the touch roll 300 . The take-up roll 400 is configured to take up the conductive film C2 that has been cooled by the cast roll 200 and manufactured.

The conductive film C2 may be composed of a single layer, or may be composed of a plurality of layers. When it is composed of a plurality of layers, a layer formed of a resin material containing a polymer material and a conductive metal filler is positioned as the outermost layer.

In the method for manufacturing a conductive film according to the present embodiment, conductive film C2 manufactured by film manufacturing apparatus 10 is further processed. Specifically, a metal thin film is formed in multiple steps on the conductive film C2. The present inventors (and others) can adjust the electrical resistance value of the conductive film C2 by changing the number of times the metal thin film is formed on the layer containing the conductive filler of the conductive film C2. I found out. In the method for producing a conductive film according to the present embodiment, a thin metal film is formed in multiple steps on the layer of the conductive film C2 containing the conductive metal filler. Therefore, according to this method for producing a conductive film, a conductive film having a desired electrical resistance value can be produced.

FIG. 2 is a diagram schematically showing a metal thin film forming apparatus 20 used in the method for producing a conductive film according to this embodiment. As shown in FIG. 2, the metal thin film forming apparatus 20 includes rollers 500 and 700, a rotating drum 600, cathodes 810 and 910, DC power sources 820 and 920, and inert gas supply sources 830 and 930. I'm in.

A vacuum pump (not shown) is attached to the metal thin film forming apparatus 20 so that the entire interior of the metal thin film forming apparatus 20 can be brought into a high vacuum.

A conductive film C<b>2 manufactured by the film manufacturing apparatus 10 is wound around the roller 500 . For example, the roller 500 is configured to feed the conductive film C2. The conductive film C2 fed out by the roller 500 passes through the sputtering chambers 800 and 900 and is wound around the roller 700. As shown in FIG. Further, the roller 700 is configured to further let out the wound conductive film C2. The conductive film C2 fed out by the roller 700 passes through the sputtering chambers 900 and 800 again and is wound around the roller 500. As shown in FIG.

Cathodes 810 and 910 are disposed in the sputtering chambers 800 and 900 at positions facing the surface of the rotating drum 600, respectively. Each of the cathodes 810 and 910 is provided with a metal (for example, copper) as a target. DC power sources 820 and 920 are configured to apply DC voltages to cathodes 810 and 910, respectively. Inert gas supplies 830 and 930 are also configured to supply an inert gas (eg, argon gas) to sputtering chambers 800 and 900, respectively.

In each of sputtering chambers 800 and 900, a metal thin film is formed on conductive film C2. More specifically, a metal thin film is formed on the layer containing the conductive metal filler in the conductive film C2. For example, a copper thin film is formed on the conductive film C2. As the conductive film C2 passes through the sputtering chamber 800 once, a metal thin film is formed on the conductive film C2. One layer of thin film is formed.

The thickness of one layer of the metal thin film is adjusted, for example, by adjusting the conveying speed of the conductive film C2. For example, by doubling the transport speed of the conductive film C2, the thickness of the metal thin film layer formed on the conductive film C2 is halved. Also, the thickness of the metal thin film layer may be adjusted by adjusting the voltage applied by the DC power supplies 820 and 920, for example. For example, by doubling the voltage applied by the DC power supplies 820, 920, the thickness of the metal thin film layer formed on the conductive film C2 is doubled. Before passing through the sputtering chambers 800 and 900, the conductive film C2 may be subjected to surface treatment such as glow treatment.

[2. Method for manufacturing conductive film]
FIG. 3 is a flow chart showing an example of the manufacturing procedure of the conductive film according to this embodiment. Each step shown in this flowchart is performed by the film manufacturing apparatus 10 or the metal thin film forming apparatus 20, for example.

Referring to FIG. 3, film manufacturing apparatus 10 produces conductive film C2 (step S100). The produced conductive film C2 is attached to the roller 500 of the metal thin film forming apparatus 20, and the metal thin film forming apparatus 20 forms one more metal thin film on the layer containing the conductive metal filler of the conductive film C2 (step S110). ).

A control device (not shown) of the metal thin film forming apparatus 20 determines whether or not the metal thin film has been formed a predetermined number of times on the conductive film C2 (step S120). The predetermined number of times is determined in advance through experiments so that each of the volume resistivity and the surface resistivity of the conductive film C2 has a desired value.

If it is determined that the metal thin film has not been formed the predetermined number of times (NO in step S120), metal thin film forming apparatus 20 forms another metal thin film on conductive film C2. On the other hand, if it is determined that the metal thin film has been formed a predetermined number of times (YES in step S120), the production of the conductive film is completed.

FIG. 4 is a flow chart showing another example of the procedure for manufacturing a conductive film according to this embodiment. Each step shown in this flowchart is performed by the film manufacturing apparatus 10 or the metal thin film forming apparatus 20, for example.

The difference between the example shown in FIG. 4 and the example shown in FIG. 3 is that step S210 is added. Below, step S210 will be described, and the description of common parts (steps S200, S220, and S230) will not be repeated.

A controller (not shown) of the metal thin film forming apparatus 20 determines the number of times to form a metal thin film on the conductive film C2 based on the target value for the electrical resistance value of the conductive film C2 (step S210). For example, the target value for the electrical resistance value of the conductive film C2 is input by the operator of the metal thin film forming apparatus 20 via an interface (not shown). The relationship between the target value of the electrical resistance value of the conductive film C2 and the number of metal thin film formations is obtained in advance through experiments, for example, and is stored in the memory in the metal thin film forming apparatus 20. FIG.

[3. feature]
As described above, in the conductive film manufacturing method according to the present embodiment, the metal thin film is formed in multiple steps on the layer containing the conductive filler of the conductive film C2. Therefore, according to this method for producing a conductive film, a conductive film having a desired electrical resistance value can be produced.

[4. Examples]
<4-1. Examples and Comparative Examples>
Conductive films of Examples 1-7 and Comparative Examples 1-3 were manufactured by using the film manufacturing apparatus 10 shown in FIG. 1 and the metal thin film forming apparatus 20 shown in FIG. The conductive films of Examples 1-7 and Comparative Examples 1-3 are described below.

(Examples 1-3 and Comparative Example 1)
The conductive films of Examples 1-3 and Comparative Example 1 differed only in the number of times the metal thin films were formed. First, common features of the conductive films of Examples 1-3 and Comparative Example 1 were as follows.

Each conductive film had a two-layer structure and a thickness of 50 μm. The first layer had a thickness of 28 μm and contained 32 wt % polypropylene (PP) and 68 wt % nickel (Ni). The thickness of the second layer was 22 μm and contained 75 wt % PP and 25 wt % carbon black (CB).

In the conductive film of Example 1, a copper thin film was formed twice on the first layer. The thickness of the copper thin film was 44 nm, and a copper thin film with a thickness of 22 nm was formed per time. In the conductive film of Example 2, a copper thin film was formed three times on the first layer. The thickness of the copper thin film was 48 nm, and a copper thin film with a thickness of 16 nm was formed per time. In the conductive film of Example 3, a thin copper film was formed on the first layer five times. The thickness of the copper thin film was 47 nm, and a copper thin film with a thickness of 9.4 nm was formed per time. In the conductive film of Comparative Example 1, a copper thin film was formed once on the first layer. The thickness of the copper thin film was 48 nm, and a copper thin film of 48 nm was formed once.

(Example 4 and Comparative Example 2)
The conductive films of Example 4 and Comparative Example 2 differed only in the number of times the metal thin films were formed. First, common features of the conductive films of Example 2 and Comparative Example 4 were as follows.

Each conductive film had a two-layer structure and a thickness of 65 μm. The first layer had a thickness of 35 μm and contained 30 wt % PP and 70 wt % copper (Cu). The thickness of the second layer was 30 μm and contained 75 wt % PP and 25 wt % CB.

In the conductive film of Example 4, a copper thin film was formed twice on the first layer. The thickness of the copper thin film was 48 nm, and a copper thin film with a thickness of 24 nm was formed per time. In the conductive film of Comparative Example 2, a copper thin film was formed once on the first layer. The thickness of the copper thin film was 51 nm, and a copper thin film of 51 nm was formed per time.

(Examples 5-7 and Comparative Example 3)
The conductive films of Examples 5-7 and Comparative Example 3 differed only in the number of times the metal thin films were formed. First, common features of the conductive films of Examples 5 to 7 and Comparative Example 3 were as follows.

Each conductive film had a single layer structure and a thickness of 50 μm. Each conductive film contained 30 wt% PP and 70 wt% Ni.

In the conductive film of Example 5, a copper thin film was formed twice. The thickness of the copper thin film was 52 nm, and a copper thin film with a thickness of 26 nm was formed per time. In the conductive film of Example 6, a copper thin film was formed three times. The thickness of the copper thin film was 48 nm, and a copper thin film with a thickness of 16 nm was formed per time. In the conductive film of Example 7, a copper thin film was formed five times. The thickness of the copper thin film was 50 nm, and a copper thin film with a thickness of 10 nm was formed in one step. In the conductive film of Comparative Example 3, a copper thin film was formed once. The thickness of the copper thin film was 49 nm, and a copper thin film of 49 nm was formed once.

<4-2. Method for measuring surface resistivity>
The surface resistivity was measured for each of the conductive films of Examples 1-7 and Comparative Examples 1-3. Specifically, the surface resistivity of each conductive film was measured by the following method. A 30 mm square test piece was cut out, and the surface resistivity was measured using a simple low resistance meter Loresta AX MCP-T370 manufactured by Nitto Seiko Analytic Tech. As a probe, PSP probe MCP-TP06P RMH112 was used. A surface resistivity (Ω/□) was obtained by multiplying a resistance value (Ω) measured with a low resistance meter by a correction factor (4.532).

<4-3. Method for measuring volume resistivity>
The volume resistivity was measured for each of the conductive films of Examples 1-7 and Comparative Examples 1-3. Specifically, the volume resistance of each conductive film was measured by the following method. A 7 cm square sample was cut from each conductive film and taken out, and the volume resistivity of the conductive film was measured using an electrical resistance measuring instrument [IMC-0240 type, manufactured by Imoto Seisakusho Co., Ltd.] and a resistance meter [RM3548 manufactured by Hioki]. did. The resistance value of the conductive film was measured with a load of 2.16 kg applied to the electrical resistance measuring instrument, and the value 60 seconds after the load was applied was defined as the resistance value of the conductive film. As shown in the following formula (1), the value obtained by multiplying the resistance value by the area of the contact surface of the jig when measuring the resistance (3.14 cm ² ) and dividing the value by the film thickness is the volume resistivity (Ω·cm). and
Volume resistivity (Ω·cm) = resistance value (Ω) x 3.14 (cm ² )/thickness (cm) (1)

<4-4. Planar Visual Evaluation>
The flatness of each of the conductive films of Examples 1-7 and Comparative Examples 1-3 was visually evaluated. Specifically, by visually observing the reflected light on each conductive film, if the smoothness of the surface of the conductive film satisfies the criteria, it is evaluated as "○", and the smoothness of the surface of the conductive film is evaluated. When the criteria were not met, it was evaluated as "△" or "X". A comparison of "Δ" and "×" indicates that the surface of "Δ" is smoother than that of "×".

<4-5. Measurement result>
The parameters and measurement results of the conductive films of Examples 1-7 and Comparative Examples 1-3 are shown in Table 1 below.

表１に示されるように、金属薄膜の形成回数を増やすことで、表面抵抗率が上昇し、体積抵抗率が減少することが確認された。すなわち、金属薄膜の形成回数を調整することによって、導電性フィルムの電気抵抗値を調整可能であることが確認された。また、金属薄膜の形成回数を増やすことで、導電性フィルムの平面度が向上することが確認された。

As shown in Table 1, it was confirmed that increasing the number of metal thin film formations increased the surface resistivity and decreased the volume resistivity. That is, it was confirmed that the electrical resistance value of the conductive film can be adjusted by adjusting the number of times the metal thin film is formed. Moreover, it was confirmed that the flatness of the conductive film was improved by increasing the number of times the metal thin film was formed.

10 film manufacturing device, 20 metal thin film forming device, 100 T die, 200 cast roll, 300 touch roll, 400 winding roll, 500,700 roller, 600 rotating drum, 800,900 sputtering chamber, 810,910 cathode, 820, 920 DC electrode, 830, 930 inert gas supply source, C1 resin composition, C2 conductive film.

Claims (3)

A method for producing a conductive film comprising a layer formed of a resin composition containing a polymer material and a conductive filler,
producing a conductive film using the resin composition;
and adjusting an electrical resistance value of the conductive film by forming a metal thin film on the layer of the conductive film in a plurality of times. further comprising determining the number of times to form the metal thin film on the layer based on a target value for the electrical resistance value of the conductive film;
2. The method of manufacturing a conductive film according to claim 1, wherein said metal thin film is formed on said layer in the determined number of times in said step of adjusting said electrical resistance value. 3. The method for producing a conductive film according to claim 1, wherein the step of adjusting the electrical resistance value adjusts the volume resistivity of the conductive film.

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