Conductive paper and preparation method thereof

Abstract

The invention relates to the technical field of conductive materials, in particular to conductive paper and a preparation method thereof. Wherein the conductive paper is prepared from 40.9 to 86.4 parts of polypyrrole / fiber composition, 1.4 to 48.7 parts of regenerated cellulose, 0.36 to 32.5 parts of glycerol and 5 to 10 parts of water, the polypyrrole / fiber composition is prepared from pyrrole, ferric trichloride and mixed fibers, and the mass ratio of the pyrrole to the ferric trichloride to the mixed fibers is (0.9 to 1.2) to (1.8 to 2.4) to (1.0 to 2.4) according to the mass of absolute dry fibers. By adopting the technical scheme provided by the invention, the mixed fibers can provide more attachment sites for pyrrole polymerization in the pyrrole polymerization process, so that polypyrrole forms more silk chains, the uniform spreading and continuity of polypyrrole in the conductive paper are improved, and the conductive paper is endowed with better conductive performance.

Description

Technical Field

[0001] The present application relates to the technical field of conductive materials, and specifically, to a conductive paper and a preparation method thereof. Background Art

[0002] Conductive paper is a special type of paper that has good electrical conductivity on the basis of the light weight and flexibility of traditional paper, and currently has good application prospects in electronic components and energy storage materials.

[0003] Polypyrrole is a typical conductive polymer with excellent electrical conductivity, optical properties and biocompatibility, and has a relatively low cost. In recent years, the preparation of polypyrrole / fiber conductive paper by in-situ polymerization of pyrrole followed by wet forming has become a research hotspot in the field of conductive materials. However, polypyrrole will damage the bonding between fibers, resulting in poor mechanical strength of the conductive paper. Moreover, the higher the polypyrrole loading, the worse the strength performance of the conductive paper under the condition of higher electrical conductivity. It is difficult to achieve a good balance between its mechanical properties and electrical conductivity, which is not conducive to subsequent processing and application. In order to obtain higher conductivity, better strength and bending characteristics, it is urgent to take measures for improvement.

[0004] Therefore, the present invention proposes a novel conductive paper and a preparation method thereof to solve the above technical problems.

[0005] In view of this, the present application is proposed. Summary of the Invention

[0006] The purpose of the present application is to provide a conductive paper and a preparation method thereof to solve at least one of the technical problems mentioned in the background art.

[0007] Specifically, in the first aspect of the present application, there is provided a conductive paper, comprising:

[0008] 40.9 - 86.4 parts of a polypyrrole / fiber composition,

[0009] 1.4 - 48.7 parts of regenerated cellulose,

[0010] 0.36 - 32.5 parts of glycerol,

[0011] 5 - 10 parts of water,

[0012] Wherein, the polypyrrole / fiber composition comprises pyrrole, ferric chloride and mixed fibers, and based on the dry fiber mass, the mass ratio between pyrrole, ferric chloride and mixed fibers is 0.9 - 1.2:1.8 - 2.4:1.0 - 2.4.

[0013] With the above technical solution, the hybrid fibers can provide more attachment sites for pyrrole polymerization during the pyrrole polymerization process, enabling polypyrrole to form more filament chains, increasing the uniform spreading and continuity of polypyrrole in the conductive paper, and endowing the conductive paper with better electrical conductivity.

[0014] Preferably, the conductive paper comprises:

[0015] 48.4 - 77.5 parts of polypyrrole / fiber composition,

[0016] 10.9 - 26.2 parts of regenerated cellulose,

[0017] 4.6 - 17.4 parts of glycerol,

[0018] 5 - 8 parts of water.

[0019] Preferably, in the polypyrrole / fiber composition, based on the mass of the absolutely dry fibers, the mass ratio among pyrrole, ferric chloride, and the hybrid fibers is 1:2:1.11 - 1.82.

[0020] Preferably, the basis weight of the conductive paper is 70 - 150 g / m 2 , the tensile strength is 20 - 150 N, the electrical conductivity is 3 - 15 S / cm, and the moisture content is 5% - 10%.

[0021] More preferably, the basis weight of the conductive paper is 78.1 - 110.5 g / m 2 , the tensile strength is 37.4 - 108.9 N, the electrical conductivity is 4.5 - 11.8 S / cm, and the moisture content is 5 - 8%.

[0022] Preferably, the preparation method of the polypyrrole / fiber composition comprises:

[0023] Placing the hybrid fibers in an ice - water bath, adding ferric chloride and pyrrole under stirring conditions, with a stirring speed of 300 - 800 rpm and a reaction time of 1 - 3 h.

[0024] Preferably, in the preparation method of the polypyrrole / fiber composition:

[0025] Adding ferric chloride and pyrrole under stirring conditions, with a stirring speed of 400 - 600 rpm and a reaction time of 1.5 - 2 h.

[0026] Preferably, the mass concentration of the hybrid fibers is 0.5 - 4%.

[0027] Preferably, the hybrid fibers include softwood pulp fibers and fines. The beating degree of the softwood pulp is 40 - 85°SR. The fines are fines of Chinese alpine rush pulp or bamboo pulp. The mass ratio of the softwood pulp in the hybrid fibers is 80% - 95%, and the mass ratio of the fines in the hybrid fibers is 5% - 20%.

[0028] Preferably, the mass ratio of softwood pulp to the mixed fibers is 85%-95%, and the mass ratio of fines to the mixed fibers is 5%-15%.

[0029] Preferably, the method for preparing the fines includes:

[0030] Beating Chinese alpine rush pulp or bamboo pulp to a beating degree of 40-70°SR, then screening with a screen mesh of 100-200 meshes, and collecting the screened pulp as the fines.

[0031] Preferably, the beating degree of the Chinese alpine rush pulp or bamboo pulp is 50-61°SR.

[0032] In the second aspect of the present application, a method for preparing the conductive paper as described in the first aspect is provided, including the steps:

[0033] Preparation step of polypyrrole / fiber slurry: Placing the mixed fibers in an ice-water bath, adding ferric chloride and pyrrole under stirring conditions, with a stirring speed of 300-800 rpm and a reaction time of 1-3 h; based on the mass of the dry fiber, the mass ratio among pyrrole, ferric chloride, and the mixed fibers is 0.9-1.2:1.8-2.4:1.0-2.4;

[0034] Preparation step of base paper: Adding 0.2%-1% wet strength agent to the polypyrrole / fiber slurry, mixing evenly, then dewatering to form a wet paper web, pressing at a pressure of 300-500 kPa for 0.5-5 min, and drying under vacuum flat pressing at 90-100°C to obtain the base paper;

[0035] Preparation step of conductive paper: Coating the surface of the base paper with a mixture of viscose solution-glycerol on one side and performing plasticization treatment with a glycerol solution;

[0036] Wherein, the viscose solution-glycerol mixture includes α-cellulose with a mass concentration of 2%-10%, sodium hydroxide with a mass concentration of 1%-6%, and glycerol with a mass concentration of 1%-5%; the mass concentration of the glycerol solution is 5%-20%.

[0037] Preferably, in the preparation step of the base paper, 0.4%-0.8% wet strength agent is added to the polypyrrole / fiber slurry.

[0038] Preferably, in the preparation step of the base paper, after dewatering to form a wet paper web, pressing is performed at a pressure of 400 kPa for 1 min, and drying under vacuum flat pressing at 95°C to obtain the base paper.

[0039] Preferably, in the steps of preparing the conductive paper, the viscose solution - glycerol mixture includes α - cellulose with a mass concentration of 3.5% - 8.5%, sodium hydroxide with a mass concentration of 5% - 6%, and glycerol with a mass concentration of 1.7% - 3%; the mass concentration of the glycerol solution is 10% - 20%.

[0040] Preferably, the wet - strength agent is polyamide epichlorohydrin resin (PAE).

[0041] Preferably, in the steps of preparing the conductive paper, the method of coating the viscose solution includes:

[0042] After coating, the coated paper is solidified in a sulfuric acid solution with a concentration of 100 - 200 g / L for 1 - 5 min to obtain regenerated cellulose. After taking out the coated paper, it is soaked and washed in hot water at 70 - 95 °C for 2 - 5 min, and then taken out and the surface moisture is blotted off.

[0043] More preferably, the coated paper is solidified in a sulfuric acid solution with a concentration of 120 - 150 g / L for 2 min to obtain regenerated cellulose. After taking out the coated paper, it is soaked and washed in hot water at 85 - 90 °C for 1 - 3 min.

[0044] Preferably, in the steps of preparing the conductive paper, the method of plasticizing treatment with the glycerol solution includes:

[0045] After blotting off the surface moisture of the coated paper, it is soaked and plasticized in a 5% - 20% glycerol solution for 2 - 10 min, taken out and dried by vacuum flat - pressing, and the drying temperature is 90 - 100 °C.

[0046] More preferably, it is soaked and plasticized in a 10% - 20% glycerol solution for 2 - 4 min, taken out and dried by vacuum flat - pressing, and the drying temperature is 95 °C.

[0047] Preferably, in the conductive paper, the absolute dry content of regenerated cellulose and glycerol is 10% - 120% of the original paper. Among them, the absolute dry amount of glycerol accounts for 10% - 60% of the total absolute dry amount of regenerated cellulose and glycerol, and regenerated cellulose accounts for 40% - 90% of the total absolute dry amount of regenerated cellulose and glycerol.

[0048] More preferably, in the conductive paper, the absolute dry content of regenerated cellulose and glycerol is 20% - 90% of the original paper. Among them, the absolute dry amount of glycerol accounts for 20% - 40% of the total absolute dry amount of regenerated cellulose and glycerol, and regenerated cellulose accounts for 60% - 80% of the total absolute dry amount of regenerated cellulose and glycerol.

[0049] In summary, the present application has the following beneficial effects:

[0050] 1. The conductive paper provided by the present application. During the polymerization process of pyrrole, the mixed fibers can provide more attachment sites for pyrrole polymerization, enabling polypyrrole to form more filament chains, increasing the uniform spreading and continuity of polypyrrole in the conductive paper, and endowing the conductive paper with better electrical conductivity.

[0051] 2. The conductive paper provided by the present application is prepared by in-situ polymerization under high pyrrole content conditions. This can not only ensure the good strength of the base paper, facilitating subsequent processing operations, but also endow the paper with better electrical conductivity characteristics.

[0052] 3. The preparation method of the conductive paper provided by the present application. By coating the viscose solution on the surface of the base paper, allowing part of it to penetrate into the microscopic pore structure of the base paper, regenerating cellulose in an acid bath, the regenerated cellulose strongly binds with softwood fibers and fines, and locks polypyrrole in the network structure, which can significantly improve the strength and bending performance of the conductive paper. Specific Embodiments

[0053] The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0054] The terms used in the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "the", and "said" used in the present application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0055] The present application will be described in detail below through embodiments.

[0056] Conductive paper is a special type of paper that has good electrical conductivity on the basis of the light weight and flexibility of traditional paper, and currently has good application prospects in electronic components and energy storage materials. However, in the prior art, the preparation process of conductive paper is complex, and it is difficult to achieve a good balance between its mechanical properties and electrical conductivity, which is not conducive to subsequent processing applications. Therefore, there is an urgent need in the art for a new type of conductive paper to solve the above technical problems.

[0057] In view of this, to solve the technical problems existing in the background art, the inventive concept of the present application is to provide a conductive paper, comprising: 40.9 - 86.4 parts of polypyrrole / fiber composition, 1.4 - 48.7 parts of regenerated cellulose, 0.36 - 32.5 parts of glycerol, and 5 - 10 parts of water; wherein, the polypyrrole / fiber composition comprises pyrrole, ferric chloride, and mixed fibers, and based on the mass of the dry fiber, the mass ratio between pyrrole, ferric chloride, and mixed fibers is 0.9 - 1.2:1.8 - 2.4:1.0 - 2.4.

[0058] According to this inventive concept, the mixed fibers can provide more attachment sites for pyrrole polymerization during the pyrrole polymerization process, enabling polypyrrole to form more silk chains, increasing the uniform spreading and continuity of polypyrrole in the conductive paper, and endowing the conductive paper with better electrical conductivity.

[0059] To better understand the above technical solution, the following will describe the above technical solution in detail in combination with specific embodiments. Those skilled in the art should also understand that the reaction time and component feeding involved in the present application cannot be absolutely precise during the actual production process, but are within the allowable error range. For example, if it is desired to control the temperature at 25°C, it may actually be 25.01°C or 24.99°C; if it is desired to weigh 30 g of the sample, it may actually be weighed as 30.001 g or 29.998 g.

[0060] Unless otherwise specified, all raw materials involved in the present application are commercially available products.

[0061] Experimental Example 1

[0062] Unless otherwise recorded, the parameters in the present application are detected using existing technologies:

[0063] Refer to the relevant paper standards GB / T 451.2 - 2023, GB / T 451.3 - 2002, GB / T 12914 - 2018, and GB / T 462 - 2023 to determine the basis weight, thickness, tensile strength, and moisture content of the conductive paper;

[0064] The conductivity of the conductive material is measured using the four-probe method.

[0065] Experimental Example 2

[0066] Unless otherwise recorded, the components of the final product in the present application are detected using existing technologies, such as:

[0067] The proportion of polypyrrole / fiber in the final product is determined based on the weight of the base paper;

[0068] The moisture proportion is determined based on the weight reduction after drying at 105°C for 1 h;

[0069] The total proportion of regenerated cellulose and glycerol is determined by subtracting the masses of polypyrrole / fiber and water from the mass of the final product;

[0070] The proportion of regenerated cellulose is determined according to the wet coating amount after the base paper is coated and the mass concentration of α-cellulose in the coating mixture, and the proportion of glycerol is determined by subtracting the mass of regenerated cellulose from the total mass of regenerated cellulose and glycerol.

[0071] Example 1

[0072] S1. Preparation of polypyrrole / fiber slurry: Pyrrole is deposited on the surface of mixed fibers by in-situ polymerization through iron ion oxidation. During the preparation, the mass concentration of the mixed fibers is 1.2%, the dosage of pyrrole is 80% relative to the mass of absolute dry fibers, and the molar ratio of ferric chloride to pyrrole is 2:1. Among them, the mixed fibers include softwood pulp fibers and fines. The beating degree of the softwood pulp is 62°SR, the fines are the fines of Chinese alpine rush pulp, the mass ratio of the softwood pulp in the mixed fibers is 90%, and the mass ratio of the fines in the mixed fibers is 10%.

[0073] The specific method for preparing the fines is as follows: First, beat the Chinese alpine rush pulp to a beating degree of 50°SR, then screen it. The mesh number of the sieve plate is 100 meshes, and the collected screened slurry is the fines.

[0074] The specific steps for depositing pyrrole on the surface of mixed fibers by in-situ polymerization through iron ion oxidation are as follows: Mix the softwood pulp and fines evenly and place them in a reaction vessel. The reaction vessel is placed in an ice-water bath. Under stirring conditions, add ferric chloride and pyrrole. The stirring speed is 500 rpm, and the reaction time is 2 h.

[0075] S2. Preparation of base paper: Add 0.5% of polyamide epichlorohydrin resin (PAE) to the polypyrrole / fiber slurry. After mixing evenly, dehydrate it with a rapid sheet former to form a wet paper web, press it at a pressure of 400 kPa for 1 min, and dry it under vacuum flat pressing at 95 °C to obtain the base paper.

[0076] S3. Preparation of conductive paper: A viscose solution - glycerol mixture is coated on the surface of the base paper, with single - side coating. The viscose solution is a cellulose xanthate solution obtained by a conventional preparation method in the art, and this cellulose xanthate solution contains α - cellulose. In the viscose solution - glycerol mixture, the mass concentration of α - cellulose is 7%, the mass concentration of sodium hydroxide is 5%, the mass concentration of glycerol is 2.5%, and the balance is water. After coating, the coated paper is coagulated in a 150 g / L sulfuric acid solution for 2 min to regenerate cellulose. After taking out the coated paper, it is soaked and washed in hot water at 90 °C for 2 min, then taken out, the surface moisture is blotted with absorbent paper, and finally it is soaked and plasticized in a 10% glycerol solution for 2 min. After taking out, it is dried by vacuum flat - pressing, and the drying temperature is 95 °C. The absolute - dry content of regenerated cellulose and glycerol in the conductive paper is 50% of the base paper. Among them, the absolute - dry amount of glycerol accounts for 20% of the total absolute - dry amount of regenerated cellulose and glycerol, and regenerated cellulose accounts for 80%.

[0077] After detection: The basis weight of the conductive paper prepared in this example is 90.2 g / m 2 , the thickness is 163 μm, the tensile strength is 69.4 N, the conductivity is 8.8 S / cm, and the moisture content is 6%; in the final product of polypyrrole / fiber conductive paper, the proportion of polypyrrole / fiber is 62.7 parts, regenerated cellulose is 25.1 parts, glycerol is 6.2 parts, and water is 6 parts.

[0078] Example 2

[0079] S1. Preparation of polypyrrole / fiber slurry: Pyrrole is deposited on the surface of the mixed fibers by in - situ polymerization through iron - ion oxidation. When preparing, the mass concentration of the mixed fibers is 2%, the dosage of pyrrole is 90% of the mass of the absolute - dry fibers, and the molar ratio of ferric chloride to pyrrole is 2:1. Among them, the mixed fibers include softwood pulp fibers and fines. The beating degree of the softwood pulp is 78 °SR, the fines are the fines of bamboo pulp, the mass ratio of the softwood pulp in the mixed fibers is 85%, and the mass ratio of the fines in the mixed fibers is 15%.

[0080] The specific preparation method of the fines is as follows: First, the bamboo pulp is beaten to a beating degree of 61 °SR, and then screened. The mesh number of the sieve plate is 150 meshes, and the collected screened pulp is the fines.

[0081] The specific steps for pyrrole to be deposited on the surface of the mixed fibers by in - situ polymerization through iron - ion oxidation are as follows: The softwood pulp and the fines are mixed evenly and placed in a reaction vessel. The reaction vessel is placed in an ice - water bath. Under stirring conditions, ferric chloride and pyrrole are added, the stirring speed is 500 rpm, and the reaction time is 2 h.

[0082] S2, Preparation of base paper: Add 0.5% polyamide epichlorohydrin resin (PAE) to the polypyrrole / fiber slurry. After mixing evenly, dehydrate it with a rapid sheet former to form a wet paper web, press it at a pressure of 400 kPa for 1 min, and dry it by vacuum flat pressing at 95°C to obtain the base paper with the basis weight of the base paper.

[0083] S3, Preparation of conductive paper: Coat the surface of the base paper with a mixture of viscose solution - glycerol, coating it on one side. The viscose solution is a cellulose xanthate solution obtained by using conventional preparation methods in the art, and this cellulose xanthate solution contains α-cellulose; in the viscose solution - glycerol mixture, the mass concentration of α-cellulose is 8%, the mass concentration of sodium hydroxide is 5.5%, the mass concentration of glycerol is 3%, and the balance is water. After coating, coagulate the coated paper in a 150 g / L sulfuric acid solution for 2 min to regenerate cellulose. After taking out the coated paper, soak and wash it in hot water at 90°C for 2 min, then take it out, absorb the surface moisture with absorbent paper, and finally soak and plasticize it in a 15% glycerol solution for 2 min. After taking it out, dry it by vacuum flat pressing at a drying temperature of 95°C. The absolute dry content of regenerated cellulose and glycerol in the conductive paper is 40% of that of the base paper. Among them, the absolute dry amount of glycerol accounts for 20% of the total absolute dry amount of regenerated cellulose and glycerol, and regenerated cellulose accounts for 80%.

[0084] After testing: The basis weight of the conductive paper prepared in this example is 110.5 g / m 2 , the thickness is 259 μm, the tensile strength is 108.9 N, the conductivity is 11.8 S / cm, and the moisture content is 5%; in the polypyrrole / fiber conductive paper of the final product, the proportion of polypyrrole / fiber is 67.8 parts, regenerated cellulose is 21.8 parts, glycerol is 5.4 parts, and water is 5 parts.

[0085] Example 3

[0086] S1, Preparation of polypyrrole / fiber slurry: Pyrrole is deposited on the surface of the mixed fibers by in-situ polymerization through iron ion oxidation. During the preparation, the mass concentration of the mixed fibers is 2.5%, the dosage of pyrrole is 55% relative to the mass of the dry fibers, and the molar ratio of ferric chloride to pyrrole is 2:1. Among them, the mixed fibers include softwood pulp fibers and fines. The beating degree of the softwood pulp is 51°SR, and the fines are the fines of Chinese alpine rush pulp. The mass ratio of the softwood pulp to the mixed fibers is 90%, and the mass ratio of the fines to the mixed fibers is 10%.

[0087] The specific preparation method of the fines is: First, beat the Chinese alpine rush pulp to a beating degree of 50°SR, and then screen it. The mesh number of the sieve plate is 150 meshes, and the collected screened pulp is the fines.

[0088] The specific steps for depositing pyrrole on the surface of mixed fibers by in-situ polymerization through iron ion oxidation are as follows: Mix softwood pulp and fines evenly and place them in a reaction vessel. The reaction vessel is placed in an ice-water bath. Under stirring conditions, add ferric chloride and pyrrole. The stirring speed is 600 rpm, and the reaction time is 1.5 h.

[0089] S2, Preparation of base paper: Add 0.8% polyamide epichlorohydrin resin (PAE) to the polypyrrole / fiber slurry. After mixing evenly, dehydrate it in a rapid sheet former to form a wet web, press it for 1 min under a pressure of 400 kPa, and dry it by vacuum flat pressing at 95 °C to obtain the base paper.

[0090] S3, Preparation of conductive paper: Coating a viscose solution-glycerol mixture on the surface of the base paper, coating on one side. The viscose solution is a cellulose xanthate solution obtained by a conventional preparation method in the art, and this cellulose xanthate solution contains α-cellulose; in the viscose solution-glycerol mixture, the mass concentration of α-cellulose is 8.5%, the mass concentration of sodium hydroxide is 6%, the mass concentration of glycerol is 1.7%, and the balance is water. After coating, solidify the coated paper in a 150 g / L sulfuric acid solution for 2 min to regenerate cellulose. Take out the coated paper and soak it in hot water at 90 °C for 3 min for washing. Then take it out, absorb the surface moisture with absorbent paper, and finally soak it in a 20% glycerol solution for plasticization for 4 min. Take it out and dry it by vacuum flat pressing, and the drying temperature is 95 °C. The absolute dry content of regenerated cellulose and glycerol in the conductive paper is 90% of that of the base paper. Among them, the absolute dry amount of glycerol accounts for 40% of the total absolute dry amount of regenerated cellulose and glycerol, and regenerated cellulose accounts for 60%.

[0091] After testing: The basis weight of the conductive paper prepared in this example is 78.1 g / m 2 , the thickness is 136 μm, the tensile strength is 55.2 N, the conductivity is 4.7 S / cm, and the moisture content is 8%; in the polypyrrole / fiber conductive paper of the final product, the proportion of polypyrrole / fiber is 48.4 parts, regenerated cellulose is 26.2 parts, glycerol is 17.4 parts, and water is 8 parts.

[0092] Example 4

[0093] S1, Preparation of polypyrrole / fiber slurry: Pyrrole is deposited on the surface of mixed fibers by in-situ polymerization through iron ion oxidation. When preparing, the mass concentration of the mixed fibers is 0.8%, the dosage of pyrrole is 70% of the mass of the absolute dry fibers, and the molar ratio of ferric chloride to pyrrole is 2:1. Among them, the mixed fibers include softwood pulp fibers and fines. The beating degree of the softwood pulp is 80 °SR, the fines are the fines of Chinese alpine rush pulp, the mass ratio of the softwood pulp in the mixed fibers is 95%, and the mass ratio of the fines in the mixed fibers is 5%.

[0094] The preparation method of the specific fine fibers is as follows: First, beat the eulaliopsis binata pulp to a beating degree of 50°SR, then perform screening with a sieve plate of 100 mesh, and collect the screened pulp, which is the fine fibers.

[0095] The specific steps for depositing pyrrole on the surface of the mixed fibers by in-situ polymerization through iron ion oxidation are as follows: Mix the softwood pulp and the fine fibers evenly and place them in a reaction vessel. The reaction vessel is placed in an ice-water bath, and ferric chloride and pyrrole are added under stirring conditions. The stirring speed is 400 rpm, and the reaction time is 2 h.

[0096] S2, Preparation of the base paper: Add 0.4% polyamide epichlorohydrin resin (PAE) to the polypyrrole / fiber pulp. After mixing evenly, dehydrate it in a rapid sheet former to form a wet paper web, press it at a pressure of 400 kPa for 1 min, and dry it under vacuum flat pressing at 95°C to obtain the base paper.

[0097] S3, Preparation of the conductive paper: Coating the surface of the base paper with a mixed solution of viscose solution - glycerol, single-sided coating. The viscose solution is a cellulose xanthate solution obtained by a conventional preparation method in the art, and this cellulose xanthate solution contains α-cellulose; in the viscose solution - glycerol mixed solution, the mass concentration of α-cellulose is 3.5%, the mass concentration of sodium hydroxide is 5%, the mass concentration of glycerol is 1.7%, and the balance is water. After coating, solidify the coated paper in a 120 g / L sulfuric acid solution for 2 min to regenerate cellulose. After taking out the coated paper, soak it in hot water at 85°C for 1 min for washing, then take it out, absorb the surface moisture with absorbent paper, and finally soak it in a 10% glycerol solution for plasticization for 2 min. After taking it out, dry it under vacuum flat pressing, and the drying temperature is 95°C. In the conductive paper, the absolute dry content of regenerated cellulose and glycerol is 20% of that of the base paper. Among them, the absolute dry amount of glycerol accounts for 30% of the total absolute dry amount of regenerated cellulose and glycerol, and regenerated cellulose accounts for 70%.

[0098] After testing: The basis weight of the conductive paper prepared in this example is 95.7 g / m 2 , the thickness is 231 μm, the tensile strength is 37.4 N, the conductivity is 4.5 S / cm, and the moisture content is 7%; in the polypyrrole / fiber conductive paper of the final product, the proportion of polypyrrole / fiber is 77.5 parts, regenerated cellulose is 10.9 parts, glycerol is 4.6 parts, and water is 7 parts.

[0099] Comparative Example 1

[0100] S1, Preparation of the polypyrrole / fiber pulp: Pyrrole is deposited on the surface of softwood pulp fibers by in-situ polymerization through iron ion oxidation. When preparing, the mass concentration of the mixed fibers is 1.2%, the dosage of pyrrole is 80% relative to the mass of the absolute dry fibers, and the molar ratio of ferric chloride to pyrrole is 2:1.

[0101] The specific steps for depositing pyrrole on the surface of mixed fibers by in-situ polymerization through iron ion oxidation are as follows: Mix the softwood pulp evenly and place it in a reaction vessel. The reaction vessel is placed in an ice-water bath. Under stirring conditions, add ferric chloride and pyrrole. The stirring speed is 500 rpm, and the reaction time is 2 h.

[0102] S2, Preparation of base paper: Add 0.5% polyamide epichlorohydrin resin (PAE) to the polypyrrole / fiber slurry. After mixing evenly, dehydrate it in a rapid sheet former to form a wet paper web, press it for 1 min under a pressure of 400 kPa, and dry it by vacuum flat pressing at 95 °C to obtain the base paper.

[0103] S3, Preparation of conductive paper: Coating the base paper surface with a viscose solution-glycerol mixture, single-sided coating. The viscose solution is a cellulose xanthate solution obtained by the conventional preparation method in the art, and this cellulose xanthate solution contains α-cellulose; in the viscose solution-glycerol mixture, the mass concentration of α-cellulose is 7%, the mass concentration of sodium hydroxide is 5%, and the mass concentration of glycerol is 2.5%. After coating, solidify the coated paper in a 150 g / L sulfuric acid solution for 2 min to regenerate cellulose. Take out the coated paper and soak it in hot water at 90 °C for 2 min for washing. Then take it out, absorb the surface moisture with absorbent paper, and finally soak it in a 10% glycerol solution for plasticization for 2 min. Take it out and dry it by vacuum flat pressing, and the drying temperature is 95 °C. The absolute dry content of regenerated cellulose and glycerol in the conductive paper is 50% of the base paper. Among them, the absolute dry amount of glycerol accounts for 20% of the total absolute dry amount of regenerated cellulose and glycerol, and regenerated cellulose accounts for 80%.

[0104] After testing: The basis weight of the conductive paper prepared in this comparative example is 90.8 g / m 2 , the thickness is 169 μm, the tensile strength is 67.7 N, the conductivity is 2.3 S / cm, and the moisture content is 6%; in the polypyrrole / fiber conductive paper of the final product, the proportion of polypyrrole / fiber is 62.7 parts, regenerated cellulose is 25.1 parts, glycerol is 6.2 parts, and water is 6 parts.

[0105] Comparative Example 2

[0106] S1, Preparation of polypyrrole / fiber slurry: Pyrrole is deposited on the surface of mixed fibers by in-situ polymerization through iron ion oxidation. When preparing, the mass concentration of the mixed fibers is 1.2%, the dosage of pyrrole is 80% of the mass of the absolute dry fibers, and the molar ratio of ferric chloride to pyrrole is 2:1. Among them, the mixed fibers include softwood pulp fibers and fines. The beating degree of the softwood pulp is 62°SR, the fines are the fines of Chinese alpine rush pulp, the mass ratio of the softwood pulp in the mixed fibers is 90%, and the mass ratio of the fines in the mixed fibers is 10%.

[0107] The preparation method of the specific fine fibers is as follows: First, beat the Chinese alpine rush pulp to a beating degree of 50°SR, then perform screening with a sieve plate of 100 mesh, and collect the screened pulp as the fine fibers.

[0108] The specific steps for depositing pyrrole on the surface of the mixed fibers by in-situ polymerization through iron ion oxidation are as follows: Mix the softwood pulp and the fine fibers evenly and place them in a reaction vessel. Place the reaction vessel in an ice-water bath, add ferric chloride and pyrrole under stirring conditions, with a stirring speed of 500 rpm and a reaction time of 2 h.

[0109] S2. Preparation of the conductive paper: Add 0.5% of polyamide epichlorohydrin resin (PAE) to the polypyrrole / fiber slurry. After mixing evenly, dehydrate it with a rapid sheet former to form a wet paper web, press it at a pressure of 400 kPa for 1 min, and dry it under vacuum flat pressing at 95°C to obtain the conductive paper.

[0110] After testing: The basis weight of the conductive paper prepared in this comparative example is 90.5 g / m 2 , the thickness is 231 μm, the tensile strength is 3.7 N, the conductivity is 9.2 S / cm, and the moisture content is 6%.

[0111] According to the above-mentioned Examples 1-4 and Comparative Examples 1-2, those skilled in the art can understand that:

[0112] First, the main difference between Comparative Example 1 and Example 1 is that the polypyrrole / fiber slurry does not contain fine fibers, and the fiber is 100% softwood pulp;

[0113] Analyzing the test results of Comparative Example 1 and Example 1, the properties of the conductive papers prepared by the two have significant differences: the conductivity of Example 1 is 8.8 S / cm, the conductivity of Comparative Example 1 is 2.3 S / cm, and the conductivity of Comparative Example 1 is reduced by 73.9% compared with Example 1; while Example 2 using the fine fibers of bamboo pulp generally obtains a significantly higher conductivity than Comparative Example 1; this shows that using the fine fibers of Chinese alpine rush pulp or bamboo pulp in this application can significantly improve the conductivity of the polypyrrole / fiber conductive paper.

[0114] Second, the main difference between Comparative Example 2 and Example 1 is that Comparative Example 2 was not coated with the viscose solution and glycerol;

[0115] Analyzing the test results of Comparative Example 2 and Example 1, the mechanical properties of the conductive papers prepared by the two have significant differences: the tensile strength of Example 1 is 69.4 N, and the tensile strength of Comparative Example 2 is only 3.7 N, with a difference of 17.7 times; and the tensile strength of the conductive papers of Examples 2-4 is also significantly higher than that of Comparative Example 2; this shows that the method of coating with the viscose solution and glycerol in this application can significantly improve the mechanical properties of the conductive paper such as the tensile strength.

[0116] Polypyrrole / fiber conductive paper is usually prepared by in-situ polymerization of pyrrole followed by wet forming. However, polypyrrole will damage the bonding between fibers, resulting in poor mechanical strength of the conductive paper. Moreover, the higher the polypyrrole loading, the worse the strength performance of the conductive paper, which is not conducive to subsequent processing and application.

[0117] According to the research of this application, the base paper of polypyrrole / fiber conductive paper contains softwood pulp, fines and polypyrrole. The softwood pulp fibers form the skeleton of the base paper and play a major supporting role. The fines are filled in the pore structure of the skeleton. When polypyrrole polymerizes, it polymerizes into chain-like polypyrrole with softwood fibers and fines as the growth points.

[0118] Furthermore, the main components of the fines are parenchyma cells, vessels, sieve tubes and other miscellaneous cells in Chinese alpine rush pulp or bamboo pulp, as well as some cut fibers. These cell walls are thin and short, with a large specific surface area, providing more attachment sites for pyrrole polymerization during the polymerization process of pyrrole, enabling polypyrrole to form more silk chains, having more contact and connection with wood pulp fibers and fines, increasing the uniform spreading and continuity of polypyrrole in the conductive paper, and thus endowing the conductive paper with better electrical conductivity.

[0119] Furthermore, softwood pulp fibers have the advantage of higher strength than most non-wood pulp after papermaking. After screening the fines in Chinese alpine rush pulp or bamboo pulp and backfilling them into the softwood pulp stock, conductive paper is prepared by in-situ polymerization under the condition of high pyrrole content, which can not only ensure the good strength of the base paper and facilitate subsequent processing operations, but also endow the paper with good electrical conductivity characteristics.

[0120] In summary, the conductive paper and its preparation method provided by this application solve the technical problem that it is difficult to balance the mechanical properties and electrical conductivity of existing conductive papers. The obtained conductive paper is easy to industrialize, has high conductivity efficiency and good mechanical properties, and has important significance for the wider production and application of conductive papers.

[0121] It should be noted that for those of ordinary skill in the art, the technical features in the above embodiments can be freely combined, and the formed technical solutions also belong to the embodiments disclosed in this application.

[0122] Furthermore, without departing from the principle of this application, several improvements and modifications can also be made to this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A conductive paper, characterized in that, Comprising: 40.9 - 86.4 parts of polypyrrole / fiber composition, 1.4 - 48.7 parts of regenerated cellulose, 0.36 - 32.5 parts of glycerol, 5 - 10 parts of water, wherein, the polypyrrole / fiber composition comprises pyrrole, ferric chloride, and mixed fibers. Based on the dry fiber mass, the mass ratio among pyrrole, ferric chloride, and mixed fibers is 0.9 - 1.2:1.8 - 2.4:1.0 - 2.

4.

2. The conductive paper according to claim 1, wherein The conductive paper comprises: 48.4 - 77.5 parts of polypyrrole / fiber composition, 10.9 - 26.2 parts of regenerated cellulose, 4.6 - 17.4 parts of glycerol, 5 - 8 parts of water.

3. The conductive paper according to claim 1, wherein The basis weight of the conductive paper is 70-150 g / m 2 , the tensile strength is 20-150 N, the conductivity is 3-15 S / cm, and the moisture content is 5%-10%.

4. The conductive paper according to claim 1, wherein The preparation method of the polypyrrole / fiber composition comprises: Placing the mixed fibers in an ice - water bath, adding ferric chloride and pyrrole under stirring conditions, with a stirring speed of 300 - 800 rpm and a reaction time of 1 - 3 h.

5. The conductive paper according to claim 1, wherein The mixed fibers comprise softwood pulp fibers and fines. The beating degree of the softwood pulp is 40 - 85°SR. The fines are fines of Chinese alpine rush pulp or bamboo pulp. The mass ratio of the softwood pulp in the mixed fibers is 80% - 95%, and the mass ratio of the fines in the mixed fibers is 5% - 20%.

6. The conductive paper according to claim 5, characterized in that, The preparation method of the fines comprises: Beating Chinese alpine rush pulp or bamboo pulp to a beating degree of 40 - 70°SR, then screening with a sieve plate mesh number of 100 - 200 meshes, and collecting the screened pulp as the fines.

7. A method for preparing the conductive paper according to any one of claims 1-6, characterized in that, Including steps: Polypyrrole / fiber slurry preparation step: Placing the mixed fibers in an ice - water bath, adding ferric chloride and pyrrole under stirring conditions, with a stirring speed of 300 - 800 rpm and a reaction time of 1 - 3 h; based on the dry fiber mass, the mass ratio among pyrrole, ferric chloride, and mixed fibers is 0.9 - 1.2:1.8 - 2.4:1.0 - 2.4; Base paper preparation step: Adding 0.2% - 1% wet - strength agent to the polypyrrole / fiber slurry, mixing evenly, then dehydrating to form a wet paper web, pressing at a pressure of 300 - 500 kPa for 0.5 - 5 min, and drying under vacuum flat - pressing at 90 - 100°C to obtain the base paper; Conductive paper preparation step: Coating a mixture of adhesive solution - glycerol on one side of the base paper surface and performing plasticizing treatment with a glycerol solution; wherein, the mixture of adhesive solution - glycerol comprises α - cellulose with a mass concentration of 2% - 10%, sodium hydroxide with a mass concentration of 1% - 6%, and glycerol with a mass concentration of 1% - 5%; the mass concentration of the glycerol solution is 5% - 20%.

8. The preparation method of the conductive paper according to claim 7, characterized in that, In the conductive paper preparation step, the mixture of adhesive solution - glycerol comprises α - cellulose with a mass concentration of 3.5% - 8.5%, sodium hydroxide with a mass concentration of 5% - 6%, and glycerol with a mass concentration of 1.7% - 3%; the mass concentration of the glycerol solution is 10% - 20%.

9. The method for preparing the conductive paper according to claim 7, wherein, The wet - strength agent is polyamide - epichlorohydrin resin.

10. According to claim 7, the preparation method of the conductive paper is characterized in that In the conductive paper preparation step, the method of coating the mixture of adhesive solution - glycerol comprises: After coating, the coated paper is solidified in a sulfuric acid solution with a concentration of 100-200 g / L for 1-5 min to obtain regenerated cellulose. After taking out the coated paper, it is soaked and washed in hot water at 70-95 °C for 2-5 min, and then taken out and the surface moisture is blotted. In the preparation step of the conductive paper, the method of plasticizing treatment with glycerol solution includes: After blotting the surface moisture of the coated paper, it is soaked and plasticized in a 5%-20% glycerol solution for 2-10 min, taken out and dried by vacuum flat pressing, and the drying temperature is 90-100 °C.