JP2012057261A - Conductive paper and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide conductive paper having excellent shield properties of 30 to 60 dB in a frequency range of 1 to 1000 MHz due to its metalization rate of almost 100% as well as excellent heat resistance and processability and provide a manufacturing method thereof in a low cost.SOLUTION: The conductive paper can be formed by mixing a wood pulp coated with electroless metal plating and a wood pulp without metal coating, and papering the mixed pulps. A weight ratio of the metal-coated wood pulp to the total weight of both of the wood pulps is from 53 to 93%.

Description

  The present invention relates to a conductive paper and a method for producing the same, and more particularly to a conductive paper containing wood pulp coated with metal by electroless metal plating and a method for producing the same.

  Conventional conductive paper made of metal fibers, carbon fiber, carbon black mixed with natural pulp and made paper (see Patent Document 1), polyester fiber plated and mixed with pulp (see Patent Document 2) Etc. have been proposed. Conductive paper made of metal fibers is excellent in electromagnetic wave shielding properties, but has poor workability and is heavy. Paper made by mixing the above is unsuitable for use as electromagnetic shielding paper because of its high electrical resistance. In addition, the above polyester fiber plated and mixed with pulp has a drawback that its use is limited due to its poor heat resistance. The conventional conductive paper as described above has problems of poor workability, high electrical resistance, and poor heat resistance.

In order to solve this problem, a conductive paper made of fibers coated with metal by metal plating has been proposed. For example, there has been proposed an electromagnetic shielding material that is a paper made with a binder containing metal-plated para-aramid fiber and para-aramid fiber pulp (see Patent Document 3). There has been proposed a fiber conductor which is a cellulose fiber coated with a metal by electroless metal plating, the fiber diameter of which is 0.005 μm to 5 μm, and the fiber length is 0.1 μm to 10,000 μm (Patent Document 4). reference). The fiber conductor is a light beam having a sheet resistance of 10 ⁶ Ω / cm ² or less and a wavelength of 400 nm to 800 nm by a process of baking the paste applied on the adherend at 100 ° C. to 600 ° C. By obtaining the characteristic that the transmittance is 90% or more, it is mainly employed in the liquid crystal panel.
In addition, an electromagnetic shielding paper in which electroless nickel plating is applied to filter paper having excellent heat resistance has been proposed, and the electromagnetic shielding paper is the same as a commercially available shielding sheet according to the experimental data of shielding characteristics using the KEC method. It has been reported that a certain degree of effect can be obtained (see Non-Patent Document 1).

  Furthermore, conductive paper made by using conductive polyester fibers (Ni-PET) coated with a nickel film by electroless plating and softwood bleached kraft pulp (NBKP) as a paper material has been reported (see Non-Patent Document 2). . As seen in the scanning electron micrograph of Fig. 2, the nickel-plated polyester fiber has metal particles adhering to the fiber surface and the surface is not uniform. And the thickness of the coating is about 0.5 μm. Therefore, for the fine conductive filler, it is necessary to evaluate the electrical characteristics in the assembled state. For the conductive paper made as the above paper, the metallization rate, Ni-PET content rate and shield The characteristic values and the like are shown in Table 3. These Ni-PETs have a nickel coating thickness of about 0.5 μm, the diameter of the fiber containing the coating is about 15 μm, and the metalization rate (nickel weight / total weight of the metallized polyester fiber) is about 40%. It is reported that all single Ni-PET fillers can be regarded as having the same degree of conductivity, only with different fiber lengths. According to Table 3, when the Ni-PET content is 70%, a value in the range of 13.1 to 33.8 dB at 1000 MHz is shown.

It has been reported that the effect of Schelkunoff, which is known as a theoretical formula for the electromagnetic wave shielding effect, can be calculated by the following formulas (4) to (7) (see Non-Patent Document 2). Here, A, R, and B are attenuation loss, reflection loss, and multiple reflection correction terms, respectively, and are the thickness t of the electronic shield material, the depth δ of the skin effect, the wave impedance, and the characteristic impedance of the electromagnetic shield material. From the ratio K, the following expression is shown. The attenuation loss A inside the electromagnetic wave shielding material can be expressed as in equation (5), and since the thickness t of the electromagnetic wave shielding material is proportional to the attenuation loss A, the thickness of the electromagnetic wave shielding material should be increased. It is shown that the shielding effect is improved.

Japanese Patent Publication No. 58-49968 Japanese Patent Publication No.59-47500 JP 2009-135526 A JP 2009-263825 A

“EMC News Letter No.18”, Yasuhiro Takamatsu, Shota Takemura, 2008 Industrial Technology Research Institute, Tokyo Metropolitan Industrial Technology Center, Tama Branch, November 2008 “Journal of the Institute of Electronics, Information and Communication Engineers”, Yasushi Nagao and two others, No. 12, pp 804-812, December 1994

Since the para-aramid fiber and para-aramid fiber pulp of Patent Document 3 are expensive, conductive paper using them becomes expensive, and it is difficult to adopt low-priced conductive paper for commercialization. . The fiber conductor of Patent Document 4 is a fiber conductor mainly used in a liquid crystal panel, and requires a step of baking at 100 ° C. to 600 ° C. because the light transmittance needs to be 90% or more. Therefore, this technique is different from a technique for producing general conductive paper, and for this reason, the sheet resistance is not a technique that can be adopted as small as 10 ⁶ Ω / cm ² or less. And the electromagnetic wave shielding paper that has electroless nickel plating on the filter paper is excellent in shielding properties and heat resistance, but by applying electroless nickel plating to the filter paper using the Kanigen method, Since plating is only applied to the surface layer of the plated filter paper, the plating on the surface layer is likely to drop off, and the flexibility of the filter paper is lost, resulting in poor workability and the possibility of commercialization. Absent.

Furthermore, the fiber conductor made from Ni-PET and NBKP as a paper stock has a metallization ratio of about 40%, and thus has a shielding property of Ni-PET content of 70% and 13.1 at 1000 MHz. Although a value in the range of ˜23.8 dB is shown, the conductive paper generally has a characteristic in the range of 30 to 60 dB at a frequency in the range of 1 to 1000 MHz. In addition to 40% to almost 100%, a frequency in the range of 30-60 dB at 1000 MHz is desired.
Therefore, in view of the above-mentioned problems of the prior art, the object of the present invention is to provide an excellent shielding property and heat resistance in the range of 30 to 60 dB at a frequency in the range of 1 to 1000 MHz by setting the metallization rate to approximately 100%. The present invention is to provide a conductive paper and a method for producing the same, which have excellent processability and can be commercialized at a low price.

The inventors of the present application have completed the present invention as a result of intensive studies to solve the above-mentioned problems. That is, the present invention is as follows.
The conductive paper according to claim 1 is formed by mixing papermaking of wood pulp that is metal-coated by electroless metal plating and wood pulp that is not metal-coated, and is metal-coated with respect to the total weight of the both wood pulps. The wood pulp has a weight ratio in the range of 53 to 93%.
The conductive paper according to claim 2 is characterized in that the metal-coated wood pulp has a plating film thickness in the range of 1.0 to 3.5 μm.
The conductive paper according to claim 3 is characterized in that the metal of the wood pulp to be metal-coated is copper, nickel, cobalt, tin or an alloy thereof.
The conductive paper according to claim 4 is characterized in that the metal-coated or non-metalized wood pulp is natural wood pulp or used wood pulp.
The conductive paper according to claim 5 is characterized in that the electrolytic shield in the range of 30 to 60 dB of the conductive paper has a frequency in the range of 1 to 1000 MHz.
The conductive paper according to claim 6 is characterized in that a volume resistivity of the conductive paper is in a range of 0.5 to 4.0.
A conductive paper manufacturing method according to claim 7 is a conductive paper manufacturing method for manufacturing a conductive paper containing wood pulp coated with metal by electroless metal plating, wherein the pulp is disaggregated from the wood chip. A first step of dispersing and drying to an absolutely dry state; a second step of sensitizing the dried pulp; washing to dry and drying to an absolutely dry state; and the activator of the dried pulp A third step of treating and drying to dryness, plating the dried pulp and washing with water, mixing the pulp dispersed in the first step with the washed pulp and making paper It consists of a fourth step of heating and pressurizing to make conductive paper, and at the end of the first, second and third steps, the treated wood pulp is dried to an absolutely dry state. And
In the conductive paper manufacturing method according to claim 8, the drying in the first, second and third steps is hindered by the treatment liquid remaining after the dispersion treatment, after the sensitizer treatment and after the activator treatment. It is characterized by preventing in advance.
The conductive paper manufacturing method according to a ninth aspect is characterized in that the plating process temperature in the fourth step is performed in a range of 45 to 75 ° C.

Since the conductive paper of the present invention is made from wood pulp, it can be commercialized at a low price. Moreover, since it is formed by mixing paper making of wood pulp not coated with metal, it has excellent processability and heat resistance. And the wood pulp has a characteristic that the metallization rate is almost 100%. If the weight ratio of the metal-coated wood pulp is in the range of 53 to 93%, the necessary number of conductive papers can be overlapped. Excellent shielding characteristics in the range of 30 to 60 dB can be easily obtained at a frequency in the range of ˜1000 MHz.
In addition, the conductive paper manufacturing method of the present invention is such that after the dispersion treatment, the sensitizer treatment liquid and the activator treatment liquid are scattered from the wood pulp by performing the drying treatment after the sensitizer treatment and after the activator treatment, the next treatment remains. It is possible to prevent obstruction by the processing liquid.

It is the schematic of the manufacturing process which shows the flow from the 1st process which disaggregates a pulp from the chip | tip of a conifer to the 4th process of producing electroconductive paper by electroless nickel plating. It is sectional drawing which expanded the nickel coat | covered pulp of electrically conductive paper 1000 times with the electron microscope. It is a top view of 55 mm x 55 mm rectangular parallelepiped conductive paper. It is the graph which showed the relationship of the plating film thickness of Example 3 whose plating temperature is 75 degreeC, and resistance with the approximated curve of the quadratic polynomial. It is the graph which showed the relationship between the plating time of each Example, and resistance with the approximated curve of the quadratic polynomial. The relationship between the plating time and the resistance is shown by an approximate curve of a second order polynomial based on the theoretical value. The relationship between plating time and resistance is shown by an approximate curve of a second-order polynomial based on experimental values. It is the graph produced by plotting the value of a frequency (MHz) and an electrolytic shield (dB) of the conductive paper of Example 1 whose weight ratio is 53, 75, 85, and 93%. Conductive paper made by mixing paper made with milk pack pulp, mixed paper made with unprocessed pulp, and mixed paper made with unprocessed newspaper paper pulp, and conductive paper made with mixed paper. It is the graph produced by plotting the value of a shield (dB).

Embodiments of the present invention will be described in detail below.
The wood pulp used for the conductive paper of the present invention may be either a conifer or a hardwood, but a conifer with long and dense fibers is preferred. In addition, used wood pulp (for example, newspaper or milk pack) can also be used.
The conductive paper of the present invention is characterized in that the weight ratio of wood pulp metal-coated by electroless metal plating and wood pulp metal-coated to the total weight of wood pulp not metal-coated is in the range of 53 to 93%. When the weight ratio is less than 53%, the electrolytic shield at a frequency in the range of 1 to 1000 MHz of the conductive paper becomes 30 dB or less, and the shielding effect cannot be obtained, and the weight ratio is less than 93%. If it is as described above, the wood pulp of the conductive paper may be easily peeled off from the surface when the mixed paper is made and dried, so the weight ratio is preferably in the range of 53 to 93%. In order to impart excellent workability to the conductive paper, the weight ratio is preferably in the range of 60 to 85.
And the electroconductive paper of the range whose said weight ratio is 53 to 93% has an effect in the frequency of the range of 1-1000 MHz with the electrolytic shield of the range of 30-60 dB by adjusting the thickness, but the said excellent In order to impart processability, conductive paper having a weight ratio in the range of 50 to 85 is preferable.

Copper, nickel, cobalt, tin or an alloy thereof is used as the metal for covering the wood pulp. Preferably, copper and nickel are preferable in consideration of shielding effect and economy, but copper and copper alloy are used in the atmosphere. Nickel is more preferable because it changes color due to dew or air pollution.
The plating film thickness of the metal-coated wood pulp increases in proportion to the plating processing temperature for performing electroless metal plating and in proportion to the plating processing time. The plating treatment temperature is in the range of 45 to 75 ° C., and the plating treatment time is 1 to 10 minutes. If the plating treatment time is 1 minute, even if the plating treatment temperature is 45 ° C., 60 ° C. or 75 ° C., the state in which the entire surface of the wood pulp is coated with metal, that is, the metallization rate is almost 100%. A thickness of 1.0 μm is obtained. Moreover, if the plating temperature is 75 ° C. and the plating time is 10 minutes, a plating film thickness of 3.5 μm is obtained.
The reason why the metallization rate of metal-coated wood pulp is almost 100% is that the surface treatment of the wood pulp is ensured by the sensitizer, so that the wood pulp surface and palladium, which is the catalyst, have an affinity, and the plating treatment By performing this, a nickel film can be uniformly formed on the surface of the wood pulp. Furthermore, since nickel is used as a catalyst for plating, the metallization rate approaches 100% as the reaction proceeds.

Next, a conductive paper manufacturing method for manufacturing the conductive paper of the present invention will be described.
The conductive paper manufacturing method of the present invention includes a first step of taking out fibers from a wood chip, dispersing the fibers and drying them into pulp, and subjecting the dried pulp to sensitizer treatment, washing with water and drying. A second step, a third step of activator drying the dried pulp, a plating treatment of the dried pulp and washing with water, and a washing of the pulp dispersed in the first step with water It consists of a fourth step of making paper by mixing with pulp, drying by heating and pressurization to make conductive paper, and at the end of the first, second and third steps, the treated wood pulp is completely dried. It is characterized by drying to a state.
By performing the drying treatment after the sensitizer treatment and after the activator treatment, the sensitizer treatment solution and the activator treatment solution are scattered from the wood pulp, so that the next treatment can be prevented from being hindered by the remaining treatment solution.
The “wood pulp” of the present invention means natural wood pulp from the viewpoint of raw materials, is used as containing used wood pulp, and means mechanical pulp from the viewpoint of manufacturing method.

(Example)
Example 1
First, the method for producing the conductive paper of Example 1 will be described in detail, and then the structure of the conductive paper will be described. The manufacturing method of the conductive paper of Example 1 is composed of the following four steps from the first to the fourth steps, showing the softwood pulp as a specific example of the wood pulp, and referring to FIG. The fourth four steps will be described.
FIG. 1 is a schematic diagram of a manufacturing process showing a flow from a first process of disaggregating pulp from a softwood chip to a fourth process of producing electroconductive paper by electroless nickel plating.
In addition, as for the manufacturing method of the conductive paper of Example 1, the temperature of the electroless nickel plating process of a 4th process is 45 degreeC, the temperature of Example 2 is 60 degreeC, and the temperature of Example 3 is 75 degreeC. Since the other processes are the same except for certain points, only the method for manufacturing the conductive paper of Example 1 will be described and the other manufacturing methods will be omitted.
1. 1st process "1. Pulp disaggregation" of FIG. 1 is demonstrated. The pulp was disaggregated by installing softwood chips in the disaggregator. The disaggregation method was performed in accordance with JIS P 8220 and the beating was performed in accordance with JIS P8221-2 (PFI mill method). A 30.0 g chip was immersed in 2 L of water and installed in a disaggregator. The speed of the propeller of the disaggregator is 10,000 revolutions / hour. A buchner was used to filter the water solution of the obscured pulp through filter paper and dehydrate the pulp water. This disaggregated pulp was placed in a dryer set at 105 ° C. to make it completely dry.

2. Sensitizer Processing “2. Sensitizer processing” in FIG. 1 will be described. In a 300 mL beaker, adjust the 5 times diluted pink puma solution to 300 mL, add 0.2 g of pulp into the solution at room temperature and stirring with a spider (rotation speed: 1200 rpm), and perform sensitizer treatment with difficulty. Carried out. The processing time for the liquid is 20 minutes. The pink pouched solution of the pulp was cut with a mesh, the pulp was immersed in 300 mL of water, and washed with water for 10 minutes while dredging (rotation speed 1200 rpm). The temperature is room temperature. The water of the pulp was dehydrated with a mesh and dried with a dryer set at 105 ° C., and dried to an absolutely dry state.
3. Activator Processing “3. Activator Processing” in FIG. 1 will be described. In a 300 mL beaker, adjust the 10-fold diluted red pouch solution to 300 mL, and while stirring at room temperature and with Ruriko (rotation speed 1200 rpm), put 0.2 g of pulp into the solution, and perform activator treatment while disaggregating. Carried out. The processing time for the liquid is 10 minutes. The pulp water was dehydrated with a mesh, dried with a dryer set at 105 ° C., and dried to an absolutely dry state.

4). Electroless Nickel Plating Treatment “4. Electroless nickel plating treatment” in FIG. 1 will be described. In a 1L beaker, adjust 10 times diluted blue summa solution to 900mL, set the heating bath temperature to 45 ° C), and stir with a stirrer (rotation speed 1200rpm), put 0.2g of pulp into the solution Then, the plating process was performed while disaggregating. Plating was performed until the plating reaction was completed. The blue puma liquor of the pulp was cut with a mesh, the pulp was immersed in 300 mL of water, and washed with water for 1 minute while dredging (rotation speed 1200 rpm). The temperature is room temperature. Water was changed 5 times and washed with water. Since the surface of the pulp was plated, it was dispersed in water. The wood pulp not coated with metal was mixed here and stirred for 10 minutes (rotation speed 1200 rpm). Next, paper was made by placing filter paper on one side of a 55 mm × 55 mm rectangular tube and placing it in a beaker, putting a solution obtained by mixing plated pulp into 500 mL of water into the tube, and lifting the tube. . A 55 mm × 55 mm paper was formed. The paper strength was increased by dissolving 10% corn starch in water and submerging the paper sandwiched between the jig and mesh in the liquid. The paper was pressed with a hot press machine at a pressure of 1 MPa and a temperature of 105 ° C. for 3 minutes to produce a conductive paper.

  The method for producing the conductive paper is characterized in that the treated wood pulp is dried in an absolutely dry state at the end of the first, second and third steps. If the plating process is performed without the drying process after the dispersion process, the sensitizer process, and the activator process, the wood pulp is not plated. This is because the wood pulp is disaggregated from the wood chip one by one, so the surface area involved with the wood pulp treatment liquid is large, and the wood pulp is easy to hydrogen bond and rich in hydrophilicity, so the treatment liquid is bound. In order to prevent the next treatment from being hindered because the treatment liquid tends to remain in the wood pulp and the next treatment will not proceed when immersed in the solution of the next treatment step. In addition, it is necessary to dry the wood pulp to an absolutely dry state.

  The thickness of the obtained conductive paper is 0.3 mm. FIG. 2 is a cross-sectional view of the conductive paper nickel-coated pulp magnified 1000 times with an electron microscope. In the state where the entire surface of the wood pulp is covered with nickel, the plating film thickness is 1.0 μm. Is obtained. About 0.2 g of nickel is plated on 0.2 g of wood pulp, the metallization rate is almost 100%, and the thickness of the coating is 1.0 μm. FIG. 2 shows that the surface of the wood pulp is completely covered with nickel with a substantially uniform thickness. FIG. 3 is a plan view of the obtained 55 mm × 55 mm rectangular conductive paper. This conductive paper is light gray and flexible, and is excellent in workability for any object that provides an electromagnetic wave shield.

FIG. 4 is an approximate linear equation showing the relationship between the plating times 1, 2, 5, and 10 minutes of Examples 1 to 3 and the plating film thickness at each time. The values of the plating film thicknesses of Examples 1 to 3 were obtained by the arithmetic average of N = 10 samples. When the plating time is 1 minute, each example shows a plating film thickness of 0.1 μm, and when the plating treatment temperature is 75 ° C. and the plating treatment time is 10 minutes, the plating film thickness is 3.5 μm. Showed.
FIG. 5 is a graph showing the relationship between the plating time and the resistance in each example as an approximation curve of a second order polynomial. It can be seen that the resistance gradually decreases to 10Ω when the plating time is 5 minutes or longer.

  FIG. 6 is a graph showing the relation between the plating film thickness and the resistance as an approximate curve of a second-order polynomial based on the theoretical value. FIG. 7 is a graph showing the relationship between the plating film thickness and resistance as an approximate curve of a second-order polynomial based on experimental values. It can be seen that the theoretical value graph of FIG. 6 and the experimental value graph of FIG. 7 are approximate.

Next, the volume resistivity of the conductive paper was measured with a four-point needle method resistivity meter. The measurement results are shown in Table 1.
Measurement was performed using the conductive paper of Example 1 as the conductive paper. Mixing the weight ratio of 53, 75, 85, and 93%, and the one that used milk pack plating as used wood pulp, the one that was not processed, and the one that was not processed, and the newspaper that was not processed The paper was made as conductive paper. As can be seen from Table 1, the volume resistivity of the conductive paper is in the range of 0.5 to 4.0, and the relationship between the weight ratio and the volume ratio is that the weight ratio is 53% and the volume ratio is 20%. The volume ratio is 75%, the volume ratio is 40%, the weight ratio is 85%, the volume ratio is 60%, the weight ratio is 93%, and the volume ratio is 80%. .

FIG. 8 plots the logarithmic scale frequency (MHz) and electrolytic shield (dB) values on the x-axis for the four types of conductive paper of Example 1 with the weight ratios of 53, 75, 85 and 93%. It is a graph created by. It can be seen that the conductive paper having a weight ratio of 93% shows a value in the range of 30 to 60 dB for the electrolytic shield with respect to the frequency in the range of 1 to 1000 MHz. On the other hand, it can be seen that the conductive paper having a weight ratio of 53, 75 and 85% shows a value of the electrolytic shield near 18 dB with respect to the frequency near 1000 MHz.
Non-Patent Document 2 shows that the shielding effect is improved by increasing the thickness of the electromagnetic shielding material, and the thickness of the conductive paper of 53, 75 and 85% is 0.3 mm. Thus, to increase 12 dB to 30 dB based on the equation shown by the effect of Schelkunoff, if the thickness is 1.2 mm which is four times the thickness, 30 dB is obtained.

FIG. 9 shows the frequency of conductive paper mixed with paper made of milk pack pulp, mixed paper made with unprocessed pulp, and conductive paper mixed with paper made of pulp processed with milk pack pulp and untreated pulp ( It is a graph created by plotting the values of (MHz) and electrolytic shield (dB).
It can be seen that the conductive paper in which the pulp of the milk pack is plated and the paper that is not processed are mixed and the electrolytic shield shows a value in the range of 30 to 60 dB with respect to the frequency in the range of 1 to 1000 MHz. . On the other hand, it can be seen that the electroconductive shield obtained by plating the pulp of the milk pack and the paper made by mixing the unprocessed newspaper pulp exhibits a value of about 19 dB for the electrolytic shield with respect to a frequency of about 1000 MHz. In order to increase this conductive paper to 12 dB by 12 dB based on the equation shown by the effect of Schelkunoff, if the thickness is 1.2 mm, which is four times the thickness, 30 dB is obtained.

  As described above, the conductive paper of the present invention can be commercialized at a low price because it uses wood pulp as a raw material, and is excellent in workability because it is formed by mixing paper making of wood pulp not coated with metal. It has heat resistance. And the wood pulp has a characteristic that the metallization rate is almost 100%. If the weight ratio of the metal-coated wood pulp is in the range of 53 to 93%, the necessary number of conductive papers can be overlapped. Excellent shielding characteristics in the range of 30 to 60 dB can be easily obtained at a frequency in the range of ˜1000 MHz.

Claims (9)

  It is formed by mixing papermaking of wood pulp that is metal-coated by electroless metal plating and wood pulp that is not metal-coated, and the weight ratio of the wood-coated wood pulp to the total weight of the both wood pulp is 53 to 93. A conductive paper characterized by being in the range of%.   2. The conductive paper according to claim 1, wherein the metal-coated wood pulp has a plating film thickness in the range of 1.0 to 3.5 μm.   The conductive paper according to claim 2, wherein the metal of the wood pulp to be metal-coated is copper, nickel, cobalt, tin, or an alloy thereof.   The conductive paper according to claim 2 or 3, wherein the wood pulp to be metallized or not is a natural wood pulp or a used wood pulp.   The conductive paper according to claim 1, wherein the electrolytic shield of the conductive paper in the range of 30 to 60 dB has a frequency in the range of 1 to 1000 MHz.   The conductive paper according to claim 1, wherein the volume resistivity of the conductive paper is in a range of 0.5 to 4.0. A conductive paper manufacturing method for manufacturing conductive paper containing wood pulp coated with metal by electroless metal plating,
A first step of disaggregating the pulp from the wood chips, dispersing it and drying it to a dry state;
A second step of treating the dried pulp with a sensitizer, washing it with water and drying it to a completely dry state;
A third step of activator-treating the dried pulp to dryness,
The dried pulp is plated and washed, and the pulp dispersed in the first step is mixed with the washed pulp to make paper, and heated and pressurized to dry to form conductive paper. Consisting of processes,
At the end of the first, second and third steps, the treated wood pulp is dried to an absolutely dry state.   The drying in the first, second and third steps prevents the subsequent treatment after the dispersion treatment, the sensitizer treatment and the activator treatment from being hindered by the remaining treatment liquid. Item 7. A method for producing a conductive paper according to Item 6.   The method for producing conductive paper according to claim 7, wherein the plating temperature in the fourth step is in the range of 45 to 75 ° C.