JP2008238406A - Conductive resin coated metal plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive resin coated metal plate capable of developing a sufficient conductivity even if contact pressure is little. <P>SOLUTION: In the conductive resin coated metal plate obtained by coating the surface of a metal plate with a conductive resin film containing conductive particles, the conductive particles are contained in the conductive resin film within a range of 20-65 mass%, Tg of the resin in the conductive resin film is -10°C-+30°C, the thickness of the conductive resin film is 1.2-14 μm. When the content of the conductive particles is set to w(mass%), the average particle size of the conductive particles is set r(μm) and the thickness of the conductive resin film is set t(μm), the formula (1): 36≤w×(r/t)≤200 is satisfied. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a resin-coated metal plate excellent in conductivity that is useful as a constituent material of a housing for an electronic device such as an audio visual (AV) device, a personal computer peripheral device, an Internet connection device, and an in-vehicle information terminal.

As a recent trend in the field of electronic equipment, further improvement in performance such as speeding up of information processing / transmission capability and increase in recording capacity is progressing, and electromagnetic waves leaking from electronic equipment tend to increase. If the leakage electromagnetic wave increases, it will cause malfunction of precision machines and other devices placed around the electronic equipment. Therefore, countermeasures are required, and the leakage of the electromagnetic wave is improved by improving the shielding property (conductivity) of the electromagnetic wave. In order to prevent this, electronic device manufacturers are demanding a metal plate with higher conductivity. In addition, from the viewpoint of cost reduction, it is also required to reduce parts such as screws when joining the metal plates as much as possible. The contact pressure at the joint between the metal plates (light contact pressure of about 10 to 12 gf / mm ^2). Bottom) However, a metal plate that exhibits good conductivity is desired.

  Conventionally, in order to impart conductivity to a resin-coated metal plate, a method of incorporating conductive particles in a resin film is known. For example, Patent Document 1 discloses a pre-coated metal plate to which conductivity is imparted by adding scaly nickel to a resin. However, in addition to conductivity, only a resistance mark resistance is evaluated. Bending workability and scratch resistance as required for resin-coated metal plates have not been studied.

In addition, Patent Document 2 by the applicant of the present application shows a resin-coated steel sheet in which a resin-coated magnetic coating containing a magnetic powder is added to an alloyed hot-dip galvanized steel sheet. Even if the contact pressure at the joint between the plates is small, it is desired to exhibit good conductivity, and examination in this respect has been insufficient.
JP-A-7-314601 JP 2006-161129 A

  Therefore, in the present invention, an object is to provide a resin-coated metal plate that can exhibit good conductivity even when the contact pressure is small.

The present invention is a conductive resin-coated metal plate in which the surface of a metal plate is coated with a conductive resin film containing conductive particles, and the conductive particles are in the range of 20 to 65% by mass in the conductive resin film. The Tg of the resin in the conductive resin film is −10 ° C. to + 30 ° C., the thickness of the conductive resin film is 1.2 to 14 μm, and the content of the conductive particles is w (mass). %), When the average particle diameter of the conductive particles is r (μm) and the thickness of the conductive resin film is t (μm), the following formula (1) is satisfied.
36 ≦ w × (r / t) ≦ 200 (1)

  The resin film is preferably obtained from a raw material composition containing an organic solvent-soluble polyester resin, and the configuration in which the metal plate is an alloyed hot-dip galvanized steel plate is a preferred embodiment of the present invention.

  In the conductive resin-coated metal plate of the present invention, a specific amount of conductive particles having an average particle diameter having a certain relationship with the film thickness is added to a resin film having a specific Tg. Thereby, the resin film is easily deformed, and the conductive particles can be appropriately exposed from the surface of the resin film. Therefore, even if the contact pressure at the time of joining metal plates is small, not only the conductive particles that are originally exposed but also the conductive particles that are covered with the resin film are exposed and contacted by deformation of the resin film. It was possible to demonstrate good conductivity.

  Further, by setting the Tg of the resin film within an appropriate range, bending workability and scratch resistance were also improved. Furthermore, when an alloyed hot-dip galvanized steel sheet having high hardness is used as the metal plate, the resin film is deformed so as to relieve the pressure applied to the resin-coated metal plate, thereby further improving the contact probability of the conductive particles.

  Therefore, the conductive resin-coated metal plate of the present invention is useful as a constituent member of a casing of an electronic device, and is particularly suitable when the contact pressure at the joint between the metal plates is small.

The conductive resin-coated metal plate according to the present invention (sometimes simply referred to as a resin-coated metal plate) includes the content w (% by mass) of conductive particles in the resin film, the Tg (° C.) of the resin in the resin film, the resin When the film thickness t (μm) is in a certain range, and the average particle diameter of the conductive particles is r (μm), w, r, and t satisfy the following formula (1). However, it has the characteristics.
36 ≦ w × (r / t) ≦ 200 (1)

  First, t, w, formulas (1), and r will be described.

  The resin film thickness t is set to 1.2 to 14 μm. If it is thinner than 1.2 μm, the conductive particles may be peeled off from the film when bending is not preferable. If it exceeds 14 μm, the conductivity is lowered and it is not preferable from the viewpoint of cost. t is more preferably 2 to 9 μm, further preferably 3 to 8 μm. t may be measured by the method of converting the specific gravity from the coating mass, or may be measured by observing the cross section of the resin coating with a microscope (SEM photograph observation).

  In the resin film, the content w of the conductive particles is 20 to 65% by mass. When the amount is less than 20% by mass, sufficient conductivity is not exhibited. When the amount exceeds 65% by mass, the amount of the matrix resin in the film is relatively reduced, and the film is liable to crack, which is not preferable. As for w, 30-60 mass% is more preferable, and 35-55 mass% is more preferable.

  In the above formula (1), w is the content of the conductive particles in the resin film as described above, and (r / t) is the thickness of the resin film because r is the average particle diameter of the conductive particles. This is a value that is an index of how large the conductive particles are with respect to t, that is, the length of the conductive particles protruding outward from the resin film surface. In the present invention, w · (r / t) is set to 36 or more and 200 or less in relation to conductivity. If it is less than 36, there exists a possibility that sufficient electroconductivity may not be exhibited, and since it will become easy for an electroconductive particle to fall out of a film | membrane when it exceeds 200, it is unpreferable. The preferable lower limit of w · (r / t) is 45, the more preferable lower limit is 50, the preferable upper limit is 150, and the more preferable upper limit is 120.

  Although the average particle diameter r of electroconductive particle will not be specifically limited if it is the range which can satisfy | fill said Formula (1), It is about 3-30 micrometers in general. In addition, this average particle diameter r is a 50% volume average particle diameter by a laser diffraction method (scattering type). The particle size distribution of the conductive particles does not need to be sharp and can be used as it is, and can be used as it is, and can be classified using a sieve or a mesh as appropriate according to the application.

  Examples of the conductive particles that can be used in the present invention include metal particles or those in which a conductive layer such as metal is provided on the surface of inorganic or organic polymer particles. As the metal particles, magnetic powder, nickel, iron phosphide and the like can be used from the viewpoint of conductivity and corrosion resistance. When there is a need to further impart electromagnetic wave absorbing performance to the metal plate, magnetic metal powder having good conductivity and also having electromagnetic wave absorbing properties may be used as the conductive particles. As such a magnetic metal powder, permalloy (Ni-Fe alloy having Ni content of 35% by mass or more), Sendust (Si-Al-Fe alloy), and the like are suitable.

  Next, the matrix resin which is the main component of the resin film will be described. The resin-coated metal plate of the present invention has a resin film formed by dispersing the conductive particles in a matrix resin on the surface of the metal plate. Examples of the matrix resin include polyester resins, acrylic resins, urethane resins, polyolefin resins, fluorine resins, silicone resins, and mixtures or modified resins of these resins. If a thermosetting resin such as an epoxy resin or an unsaturated polyester resin is used as a raw material for the matrix resin, the resulting cured coating film becomes too hard and has a low deformability, which is not preferable in the present invention. Since the resin-coated metal plate of the present invention is mainly used for a housing of an electronic device, considering that characteristics such as bending workability, film adhesion, and corrosion resistance are required, an organic solvent soluble type (non- A crystalline polyester resin is preferred.

  As the organic solvent-soluble polyester resin, “Byron (registered trademark)” series manufactured by Toyobo Co., Ltd. is preferable in that a wide variety of types can be obtained. The polyester resin may be crosslinked with a melamine resin or the like. As the melamine resin, there are “Sumimar (registered trademark)” series manufactured by Sumitomo Chemical Co., Ltd. and “Cymel (registered trademark)” series manufactured by Mitsui Cytec.

  In the resin-coated metal plate of the present invention, the Tg of the matrix resin in the resin film formed on the metal plate must be −10 ° C. to + 30 ° C. This is because, by setting Tg within this range, the deformability of the resin film is improved, and appropriate exposure of the conductive particles becomes possible. When Tg is lower than −10 ° C., the matrix resin is too soft and inferior in scratch resistance. However, when Tg exceeds 30 ° C., the deformability of the resin is lowered and the conductivity is lowered.

  The Tg of the matrix resin means a Tg value actually measured by Tg measurement of the entire resin film. The resin film may contain known additives such as a rust preventive agent, a matting agent, and a pigment in addition to a matrix resin (which may be a resin + crosslinking agent), but Tg is a dispersed solid additive. It is because it is not influenced by.

  Therefore, when the matrix resin is not crosslinked, the Tg of the matrix resin becomes the Tg of the entire resin film. Moreover, what is necessary is just to adjust the compounding quantity of a crosslinking agent appropriately so that Tg of the matrix resin after bridge | crosslinking may be -10 degreeC-+30 degreeC when bridge | crosslinking. In addition, the ratio of the resin and the cross-linking agent is blended so that the cross-linking agent (after reaction) is 5 to 30% by mass in the resin film after drying from the viewpoint of the balance between processability and durability. Is preferred.

  In the present invention, Tg is measured by scraping a resin film from a metal plate and using a differential scanning calorimeter (DSC) in a nitrogen atmosphere at a temperature range of −100 ° C. to 180 ° C. and a heating rate of 20 ° C./min.

The Tg of the Byron (registered trademark) series manufactured by Toyobo Co., Ltd. is as follows. Byron 103 (47 ° C), Byron 200 (67 ° C), Byron 220 (53 ° C), Byron 226 (65 ° C), Byron 240 (60 ° C), Byron 245 (60 ° C), Byron 270 (67 ° C), Byron 280 (68 ° C), Byron 290 (72 ° C), Byron 296 (71 ° C), Byron 300 (7 ° C), Byron 500 (4 ° C), Byron 530 (5 ° C), Byron 550 (-15 ° C), Byron 560 (7 ° C), Byron 600 (47 ° C), Byron 630 (7 ° C), Byron 650 (10 ° C), Byron GK110 (50 ° C), Byron GK130 (15 ° C), Byron GK140 (20 ° C), Byron GK150 (20 ° C), Byron GK180 (0 ° C), Byron GK190 (11 ° C), Byron GK250 (60 ° C) Byron GK330 (16 ° C), Byron GK590 (15 ° C), Byron GK640 (79 ° C), Byron GK680 (10 ° C), Byron GK780 (36 ° C), Byron GK810 (46 ° C), Byron GK880 (84 ° C), Byron GK890 (17 degreeC), Byron BX1001 (-18 degreeC) etc. are mentioned. These Tg are temperatures described in the catalog. These molecular weight (Mn) in the range of ^{3 × 10 3 ~30 × 10 3} .

  As an original plate of the resin-coated metal plate of the present invention, an aluminum plate, a copper plate, a cold-rolled steel plate, a hot-dip galvanized steel plate, an electrogalvanized steel plate, an alloy-plated steel plate and the like can be used. Especially, the alloy plating steel plate of zinc and an iron group element (Fe, Co, Ni) is preferable. Since these alloy-plated steel plates have high hardness as metal plates, the pressure applied to the resin-coated metal plate is not relaxed by deformation of the metal plate, but the resin film is deformed in an attempt to relax. The contact probability of the active particles is further improved. Among these alloy-plated steel sheets, an alloyed hot-dip galvanized steel sheet (GA steel sheet) having a plating layer obtained by alloying zinc and iron is more preferable. Iron is excellent in electromagnetic wave absorptivity, and since iron in plating contributes to absorption of electromagnetic waves, higher electromagnetic wave shielding properties can be exhibited by using a GA steel plate as an original plate.

From the viewpoint of ensuring moldability, the Fe, Ni, and Co contents are preferably controlled to about 5 to 20% by mass. The detailed plating conditions of the hot dipping method are not particularly limited, and a method usually used for alloying can be employed. In consideration of electromagnetic wave absorbability, the amount of adhesion of the plating is preferably small. For example, it is preferably 50 g / m ² or less, more preferably 40 g / m ² or less, and 35 g / m ² or less. Is more preferable, and is most preferably 30 g / m ² or less. The lower limit of the coating weight is not particularly limited from the viewpoint of electromagnetic wave absorbent, considering the corrosion resistance and the like, is preferably from 5 g / m ^2, and more preferably 10 g / m ^2.

  In order to produce the resin-coated metal sheet of the present invention, it is preferable to employ a method in which a raw material composition for a resin film is prepared and applied to the metal sheet and dried. As the raw material composition, a matrix resin, a crosslinking agent added if necessary, etc., diluted with an organic solvent or the like to have a viscosity suitable for coating is used. The organic solvent is not particularly limited, but aromatic hydrocarbons such as toluene and xylene; aliphatic esters such as ethyl acetate and butyl acetate; alicyclic hydrocarbons such as cyclohexane; aliphatic carbonization such as hexane and pentane. Hydrogen etc .; Ketones such as methyl ethyl ketone and cyclohexanone are listed. The solid content concentration of the raw material composition is preferably about 5 to 45% by mass.

  Various known additives used in the field of resin-coated metal plates, such as matting agents, extender pigments, rust preventives, anti-settling agents, and waxes, are added to the raw material composition as long as the object of the present invention is not impaired. May be. Further, an additive for imparting heat dissipation properties such as carbon black may be added.

  The method for applying the raw material composition to the metal plate is not particularly limited, and a bar coater method, a roll coater method, a spray method, a curtain flow coater method, or the like can be employed. Although drying is performed after coating, in a crosslinking agent addition system, it is preferable to perform drying by heating at a temperature at which the crosslinking agent can react. Specifically, heat drying is preferably performed at 100 to 250 ° C. for about 1 to 5 minutes. The metal plate may be subjected to a known surface treatment (primary treatment) such as chromate treatment or phosphate treatment in advance for the purpose of improving corrosion resistance, improving adhesion to the resin film, and the like. Alternatively, a non-chromated metal plate may be used in consideration of environmental pollution and the like.

  As described above, the resin-coated metal plate of the present invention is obtained by laminating a resin film containing conductive particles on a metal plate. For example, when the resin film is used as a casing of an electronic device, this resin film is formed on the inner side of the casing. Use to become. If necessary, another resin film (overcoat layer) may be applied to the surface of the resin film in order to improve the scratch resistance, fingerprint resistance, and the like. However, it is important that the overcoat layer is a thin film that prevents exposure of the conductive particles and does not lower the conductivity, specifically 0.2 to 1.5 μm, more preferably 0.4 to The thickness is about 1.2 μm.

  The present invention will be described in more detail with reference to the following examples. However, the following examples are not intended to limit the present invention, and modifications within the scope of the present invention are included in the present invention. Unless otherwise specified, “%” indicates “mass%” and “part” indicates “part by mass”.

[Metal plate]
The metal plates used and their abbreviations are shown below. The plating was performed on both sides of the metal plate.
GA: Alloyed hot-dip galvanized steel sheet: Plate thickness: 0.8 mm, plating coating amount: 30 g / m ^{2 on} each side, Fe content during plating: 8.6%
EG: Electrogalvanized steel sheet: plate thickness: 0.8 mm, plating adhesion amount: 20 g / m ^{2 on} one side GI: Hot dip galvanized steel sheet: plate thickness: 0.6 mm, plating adhesion amount: 60 g / m ^{2 on} one side Al: Aluminum plate ... Thickness: 0.6mm

[Matrix resin]
An organic solvent-soluble polyester resin Byron (registered trademark) series manufactured by Toyobo Co., Ltd. was used. The type and Tg used are shown.
Byron 550 (Tg: −15 ° C.), Byron 500 (Tg: 4 ° C.), Byron GK130 (Tg: 15 ° C.), Byron GK140 (Tg: 20 ° C.), Byron GK780 (Tg: 36 ° C.), Byron 296 (Tg) : 71 ° C)

[Crosslinking agent]
A melamine resin (“Sumimar (registered trademark) M-40ST” manufactured by Sumitomo Chemical Co., Ltd.) was used.

[Conductive particles]
Fe-Ni alloy magnetic powder (Mitsubishi Steel Permalloy: 78Ni-1Mo-FP; average particle size 7.6 μm; abbreviated as Fe-Ni in the table)
Nickel powder (“CNS-10” manufactured by Nikko Rica Corporation; average particle size 6.3 μm; abbreviated as Ni in the table)
・ Iron phosphide ("P-Fe-350" manufactured by Fukuda Metal Foil Industry Co., Ltd., pulverized with a pulverizer so as to have an average particle size of 7.0 µm)

  In addition, these average particle diameters are 50% volume average particle diameters measured by a laser diffraction method (scattering method) using Microtrac FRA9220 manufactured by Leeds & Northrup.

[Preparation of resin film raw material composition]
Various resins having different Tg and the above crosslinking agent (solid content 80%) were mixed at a mass ratio of 9: 1 to form a matrix resin, and the amounts of conductive particles shown in Tables 1 to 10 (content in the resin film) Further, carbon black for heat dissipation (manufactured by Mitsubishi Chemical Co., Ltd .; particle size 25 nm) was added so as to be 10% in 100% of the solid content of the composition. The raw material composition was diluted with a xylene / cyclohexanone mixed solvent (xylene: cyclohexanone = 1: 1) so that the solid content concentration would be 10 to 30%, and stirred with a hand homogenizer at 10,000 rpm for 10 minutes. Was prepared.

  The resin with Tg of −6 ° C. is a mixture of Byron 550 and Byron 600 at 85:15, and the resin with Tg of 26 ° C. is a mixture of Byron GK140 and Byron GK780 at 63:37. It is.

[Preparation of top coat]
Byron 500, Byron GK780 and Byron 296 having the Tg shown in Table 10 were used. Various resins and the above crosslinking agent are mixed at a mass ratio of 9: 1 and diluted with a xylene / cyclohexanone mixed solvent (xylene: cyclohexanone = 1: 1) so that the solid content concentration becomes 7.5%. The mixture was stirred with a homogenizer at 10,000 rpm for 10 minutes to prepare a top coat.

[Production of resin-coated metal sheet]
The raw material composition for the resin film was applied to various metal plates shown in Tables 1 to 10 with a bar coat so as to have the film thicknesses shown in Tables 1 to 10, and reached the plate temperature in a hot air drying furnace. Baking was carried out at 230 ° C. for about 120 seconds to produce a resin-coated metal plate.

[Measurement of Tg]
Based on JIS K7121, the measurement was performed using a differential scanning calorimeter (trade name: Thermo Plus DSC8230: manufactured by Rigaku Corporation). Specifically, the resin film was scraped off with a cutter knife from the resin-coated metal plate produced as described above, and a sample was collected. This sample was set in a differential scanning calorimeter, cooled to −100 ° C., and when stabilized, the temperature was raised to 180 ° C. at a rate of 20 ° C./min. From the obtained DSC curve, the glass transition temperature (Tg) Asked.

[Measurement and evaluation criteria for conductivity]
Using a tester [Analog tester CX-270N made by Custom Co., Ltd.], the electrical resistance of the surface of the resin-coated metal plate was measured as follows. As shown in FIG. 1, the two terminals are held at an angle of 45 ° with the resin film, and the surface of the resin film is traced lightly at an average speed of 30 mm / second. The measurement length was 100 mm. The pressure during the measurement was performed under light contact so that only the terminal weight (7 g) was obtained. When the measured value (resistance value) was stabilized after 1 second or more from the start of measurement, the resistance value was read. This operation was performed 10 times in total at different measurement locations, and the average value was taken as the resistance value. If this resistance value was 500Ω or less, it was evaluated as “O” if there was no practical problem, and if it exceeded 500Ω, “X” was determined because of poor conductivity.

[Bending workability]
Using the type 2 test apparatus described in JIS K5600-5-1, the 0T bend (180 ° bend) is performed, and the resin film after bending (the resin film is bent outside the bent portion) (Existing) was observed visually. If there was peeling, it was rated as x, and if not, it was marked as o.

[Rust resistance]
A pencil hardness test in accordance with JIS K5600-5-4 was conducted, and with H pencil, “no wrinkle” was marked with “疵” and wrinkled with “x”.

Experiment No. 1
The relationship between the Tg of the resin film and the conductivity was examined. GA was used for the metal plate, and Fe—Ni alloy magnetic powder (average particle diameter r: 7.6 μm) was used for the conductive particles. The conductive particle amount w was fixed at 50%, and the resin film thickness t was adjusted to around 6 μm and around 9 μm. The measurement results are shown in Table 1. If the Tg of the resin film is in the range of −10 ° C. to + 30 ° C., it can be seen that the resin film is excellent in all of conductivity, bending workability, and scratch resistance.

Experiment No. 2
Using resin with a Tg of −6 ° C., GA, and Fe—Ni alloy magnetic powder, and changing the amount w of conductive particles and the thickness (film thickness) t of the resin film, w in the formula (1) -(R / t) was changed and the relationship with conductivity was examined. The measurement results are shown in Table 2. When w is 20 to 65% and w · (r / t) is 36 or more and 200 or less, it can be seen that all of conductivity, bending workability, and wrinkle resistance are excellent.

Experiment No. 3
The effect of the type of metal plate and the type of conductive particles on the conductivity was examined, and the results are shown in Table 3. Even if the conductive particles are different, if the formula (1) is not satisfied, the conductivity is poor. If the metal plate or the conductive particles are different but the formula (1) is satisfied, the conductivity and bending process are not satisfied. It can be seen that it is excellent in all properties and scratch resistance.

Experiment No. 4
Using a resin with a Tg of 4 ° C., the experiment No. The same experiment as in 2 was performed and the results are shown in Table 4. Experiment No. 2 showed the same tendency.

Experiment No. 5
Using a resin with a Tg of 4 ° C., the experiment No. 3 and the results are shown in Table 5. Experiment No. 3 showed the same tendency.

Experiment No. 6
Using a resin with a Tg of the resin film of 15 ° C., Experiment No. The experiment similar to 2 was performed and the results are shown in Table 6. Experiment No. 2 showed the same tendency.

Experiment No. 7
Using a resin with a Tg of the resin film of 15 ° C., Experiment No. The same experiment as in No. 3 was performed, and the results are shown in Table 7. Experiment No. 3 showed the same tendency.

Experiment No. 8
Using a resin with a Tg of 26 ° C., an experiment No. The same experiment as in 2 was performed, and the results are shown in Table 8. Experiment No. 2 showed the same tendency.

Experiment No. 9
Using a resin with a Tg of 26 ° C., an experiment No. 3 and the results are shown in Table 9. Experiment No. 3 showed the same tendency.

Experiment No. 10
Using resin with a Tg of −15 ° C. and 36 ° C., the characteristics when the formula (1) is satisfied were examined, and the results are shown in Table 10. It was confirmed that the one with 36 ° C. was inferior in conductivity.

  Further, the properties when a top coat film was formed using a resin having a Tg of 4 ° C. were examined, and the results are shown in Table 10. Since the top coat film is a thin film, the conductivity was not adversely affected even when Tg was high.

  The resin-coated metal plate of the present invention is useful as a constituent member of a casing of an electronic device. As said electronic equipment, information recording products such as CD, LD, DVD, CD-ROM, CD-RAM, PDP, LCD; electrical / electronic / communication related products such as personal computers, car navigation systems, car audio visual equipment; Examples thereof include audio-visual equipment such as a projector, a television, a video, and a game machine. Further, it can be used as a constituent member of a copying machine such as a copying machine or a printer, as a power box cover or a control box cover of an air conditioner outdoor unit, or as a constituent member of a vending machine or a refrigerator.

It is explanatory drawing of the measuring method of the electroconductivity of a resin coating metal plate.

Claims (3)

A conductive resin-coated metal plate coated with a conductive resin film containing conductive particles on the surface of the metal plate,
Conductive particles are contained in the range of 20 to 65 mass% in the conductive resin film, the Tg of the resin in the conductive resin film is −10 ° C. to + 30 ° C., and the thickness of the conductive resin film is 1. When the content of the conductive particles is w (mass%), the average particle size of the conductive particles is r (μm), and the thickness of the conductive resin film is t (μm). A conductive resin-coated metal plate satisfying the formula (1).
36 ≦ w × (r / t) ≦ 200 (1)   The conductive resin-coated metal sheet according to claim 1, wherein the resin film is obtained from a raw material composition containing an organic solvent-soluble polyester resin.   The conductive metal-coated metal sheet according to claim 1 or 2, wherein the metal sheet is an alloyed hot-dip galvanized steel sheet.