Carbon-free solid electrolytic aluminum capacitor paper and method for manufacturing the same

Abstract

This invention relates to the field of electrolytic capacitor paper preparation technology, and more particularly to a carbon-free solid aluminum electrolytic capacitor paper and its preparation method. This method significantly improves the performance of the electrolytic capacitor paper by adding bamboo fiber pulp to hemp pulp and subjecting it to ultrasonic dispersion treatment, combined with chemical cross-linking treatment. This technology not only improves the dispersion and uniformity of the fibers, but also enhances the bonding force between fibers, thereby increasing the paper's adsorption capacity, mechanical strength, and electrical properties, reducing the occurrence of side reactions, and thus improving the stability and service life of the capacitor. Simultaneously, the carbon-free process simplifies the production process, saves energy, and reduces environmental impact. These technical effects give the low-density carbon-free solid electrolytic capacitor paper of this invention significant advantages in performance, production efficiency, and environmental friendliness.

Description

Technical Field

[0001] This invention relates to the field of electrolytic capacitor paper preparation technology, and in particular to a carbon-free solid aluminum electrolytic capacitor paper and its preparation method. Background Technology

[0002] Solid-state electrolytic capacitors are key components widely used in electronic products, especially in power electronics, communication equipment, and home appliances. Their basic structure includes an anode, cathode, electrolytic paper, and a solid conductive polymer material. The electrolytic capacitor paper is an indispensable raw material, primarily used to adsorb conductive polymer monomers and oxidants to form a polymer, and also acts as an insulating plate, preventing direct contact between the anode and cathode, thus avoiding short circuits.

[0003] Currently, most traditional electrolytic capacitor papers use cellulose-based materials as raw materials. These papers typically have several problems: First, cellulose materials have a weak adsorption capacity for conductive polymer monomers, affecting the performance of the capacitor paper; second, cellulose contains a large number of hydroxyl groups, which can easily produce side reactions during the polymerization of conductive polymer monomers, thus affecting the electrical performance of the capacitor. At the same time, the fibers of traditional electrolytic paper are tightly bonded, preventing the conductive polymer monomers from being completely adsorbed into the electrolytic paper. This results in uneven distribution of the monomers after polymerization within the electrolytic paper, affecting the performance and stability of the capacitor.

[0004] To address the aforementioned issues, existing technologies employ carbonization to improve the porosity of electrolytic capacitor paper, thereby enhancing its adsorption and conductivity. In this process, the electrolytic paper typically undergoes carbonization at a high temperature of 250-270℃ to loosen the paper and enhance its adsorption capacity for conductive polymer monomers. However, high-temperature carbonization has several drawbacks: firstly, the production process is complex and energy-intensive; secondly, high-temperature treatment may damage the structure of the anode and cathode foils, leading to unstable product performance and excessive leakage current; finally, high-temperature carbonization consumes a significant amount of energy, increasing production costs. Therefore, developing carbonization-free solid-state electrolytic capacitor paper that simplifies the production process, reduces energy consumption, and improves the paper's adsorption and electrical properties has become a research hotspot in the field of electrolytic capacitor paper.

[0005] In recent years, research on developing carbon-free solid-state electrolytic capacitor paper has gradually become a trend. Carbon-free capacitor paper does not require high-temperature carbonization. By optimizing the raw materials and preparation process, the paper's adsorption capacity and stability can be effectively improved, while reducing energy consumption and environmental impact during production. This type of capacitor paper not only has good adsorption properties but also reduces side reactions during the polymerization of conductive polymer monomers, thus exhibiting better electrical performance and lower leakage current.

[0006] Currently, various methods have been proposed for preparing carbon-free solid electrolytic capacitor paper. Among them, the composite of plant fibers and chemical fibers is a relatively common technical solution. For example, the Chinese invention patent application filed by the applicant (Publication No.: CN109208375 A, Publication Date: 2019.01.15) discloses that the raw materials of the electrolytic capacitor paper are composed of hemp pulp and chemical fibers; the freeness of the hemp pulp is 10~30°SR, and the wet weight is 10~40g; the length of the chemical fibers is 1.5~15mm, and the fineness is 0.1~3dtex; by dry weight percentage, the hemp pulp is 10~80%, and the chemical fibers are 20~90%.

[0007] However, existing carbon-free solid electrolytic capacitor papers still face some challenges. For example, most current technologies use a composite of plant and chemical fibers, but the selection and ratio of fibers, as well as the pulp processing methods, have not yet achieved optimal results, leading to paper performance that falls short of expectations. Furthermore, there is still room for further optimization in terms of monomer adsorption and uniform distribution. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention provides a method for preparing carbon-free solid aluminum electrolytic capacitor paper. This method significantly improves the performance of the electrolytic capacitor paper by adding bamboo fiber pulp to hemp pulp and subjecting it to ultrasonic dispersion treatment, combined with chemical cross-linking. This technology not only improves the dispersion and uniformity of the fibers but also enhances the bonding force between fibers, thereby increasing the paper's adsorption capacity, mechanical strength, and electrical properties, reducing side reactions, and ultimately improving the stability and lifespan of the capacitor. Simultaneously, the carbon-free process simplifies the production process, saves energy, and reduces environmental impact. These technical effects give the low-density carbon-free solid electrolytic capacitor paper of this invention significant advantages in performance, production efficiency, and environmental friendliness.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A method for preparing carbon-free solid aluminum electrolytic capacitor paper, using bamboo fiber, jute pulp and polyester fiber as main raw materials, includes the following steps:

[0011] 1) Add bamboo fiber pulp to hemp pulp and disperse the pulp using ultrasonic treatment. The ultrasonic treatment power is 200-500W and the treatment time is 5-10 minutes.

[0012] 2) Add polyester fiber to the cross-linked bamboo fiber jute pulp and mix. The dry weight ratio of bamboo fiber, jute pulp and polyester fiber is 20-30%: 20-40%: 30-60%.

[0013] 3) Add a chemical crosslinking agent for chemical crosslinking treatment. The chemical crosslinking agent is a polyhydroxy compound or a polymer crosslinking agent. The concentration of the crosslinking agent is 1%-5%, the crosslinking temperature is 60-80℃, and the treatment time is 30-60 minutes.

[0014] 4) The mixed fiber slurry is formed by the rotary screen forming method. The formed capacitor paper is then pressed and dried to obtain low-density, carbon-free solid electrolytic capacitor paper.

[0015] Preferably, the hemp pulp in step 1) is selected from one or more of the following: sisal pulp, Manila hemp pulp, jute pulp, hemp pulp, flax pulp, gampi pulp, pineapple leaf pulp, and sandalwood bark pulp.

[0016] Preferably, the crosslinking agent in step 1) is one or more of polyethyleneimine, pentanediol, polyacrylic acid, or polyurethane.

[0017] Preferably, in step 1), the crosslinking agent is polyethyleneimine, the concentration of the crosslinking agent is 1.5%, the crosslinking temperature is 70°C, and the treatment time is 45 minutes.

[0018] Preferably, in step 1), the beating degree of bamboo fiber pulp and jute pulp is 10-30°SR, and the wet weight is 15-30g.

[0019] Preferably, the polyester fiber has a length of 0.2-1.5 dtex and a length of 3-10 mm.

[0020] Preferably, the paper is dried at 70-90°C, and the density of the dried paper is 0.2-0.5 g / cm³. 3 .

[0021] Preferably, a thickener is added to the mixed fiber pulp in step 2), and the amount of thickener added is 1.0-5.0% of the dry weight of the paper.

[0022] Preferably, the thickener is one or more of rosin, gum arabic, xanthan gum, carrageenan, and polyvinyl alcohol.

[0023] Furthermore, the present invention also provides carbon-free solid aluminum electrolytic capacitor paper prepared by the method.

[0024] This invention, by employing the above-mentioned technical solution and using a composite material of bamboo fiber, hemp pulp, and polyester fiber, combined with ultrasonic dispersion treatment and chemical crosslinking treatment, significantly improves the performance of electrolytic capacitor paper and has the following outstanding technical effects:

[0025] 1. Improved pulp uniformity and fiber dispersion: Ultrasonic dispersion treatment effectively breaks up fiber aggregation and agglomeration, resulting in more uniform fiber dispersion in bamboo and jute pulp. Ultrasonic treatment ensures uniform fiber distribution in the pulp, thereby improving the structural uniformity and performance consistency of the paper. This treatment method significantly increases the contact area between fibers, providing a better foundation for subsequent cross-linking reactions and enhancing the overall stability of the paper.

[0026] 2. Enhanced interfiber bonding and improved adsorption: By adding chemical cross-linking agents (such as polyethyleneimine and pentanediol), a cross-linked structure is formed in bamboo fiber, jute pulp, and polyester fiber, enhancing the bonding force between fibers. The cross-linked paper not only improves structural stability but also significantly enhances its adsorption of conductive polymer monomers. The paper can more uniformly adsorb conductive monomers, resulting in a more even distribution within the capacitor, thereby improving the capacitor's electrical performance and reducing leakage current.

[0027] 3. Reduced side reactions and improved electrical performance: In traditional electrolytic capacitor paper, the hydroxyl groups of cellulose easily react with conductive polymer monomers, affecting the monomer polymerization process and reducing capacitor performance. This invention, through chemical cross-linking, reduces the number of free hydroxyl groups, thereby significantly reducing side reactions. The cross-linked paper can effectively control the uniformity and efficiency of the monomer polymerization reaction, improving the electrical performance of the electrolytic capacitor paper, giving it higher stability and lower leakage current.

[0028] 4. Improved Mechanical Properties and Stability: Chemical cross-linking not only enhances the bonding force of the fibers but also improves the mechanical strength and toughness of the paper. The tensile strength, compressive strength, and tear resistance of the paper are significantly improved, especially its stability under humid or high-temperature conditions. These improved mechanical properties make electrolytic capacitor paper more durable during production, better able to withstand mechanical pressure and environmental stress, and extend the lifespan of the capacitors.

[0029] 5. Carbonization-free process, reducing production energy consumption: This invention employs a carbonization-free production process, avoiding the high-temperature carbonization process required in the production of traditional solid-state electrolytic capacitor paper. The elimination of high-temperature heating significantly reduces energy consumption during production and simplifies the production steps. This improvement not only effectively reduces the high energy consumption generated during carbonization but also avoids potential damage to internal capacitor components (such as cathode and anode foils) caused by high temperatures, reducing equipment energy consumption and production costs.

[0030] 6. Optimize production efficiency and improve production stability: By combining ultrasonic dispersion treatment and chemical cross-linking treatment, this invention improves the uniformity and consistency of paper, reduces unstable factors in the production process, and makes the production process more efficient and controllable. In addition, through the cylinder forming method and reasonable pulp treatment, the forming quality of paper is guaranteed, thereby improving production efficiency, reducing material waste, and ensuring the performance consistency of each batch of products.

[0031] 7. Environmental friendliness and sustainability: The bamboo fiber and hemp pulp used in this invention are both natural and renewable resources with good biodegradability. Compared with traditional high-temperature carbonization processes, this invention not only avoids the problem of excessive energy consumption but also reduces the environmental impact during production.

[0032] In summary, this invention, by employing a composite material of bamboo fiber, hemp pulp, and polyester fiber, combined with ultrasonic dispersion and chemical cross-linking treatments, significantly improves the adsorption, mechanical properties, electrical properties, and stability of low-density, carbon-free solid electrolytic capacitor paper. Furthermore, this technology effectively reduces production energy consumption, simplifies the production process, and minimizes negative environmental impacts, thereby optimizing production efficiency, cost, and environmental friendliness. In conclusion, this invention provides a high-performance, environmentally friendly, and low-energy-consumption method for preparing solid electrolytic capacitor paper, with broad application prospects. Detailed Implementation

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present invention.

[0034] Example 1

[0035] Bamboo fiber pulp: freeness 18°SR, wet weight 25g, pulp concentration 2%;

[0036] Jute pulp: freeness 16°SR, wet weight 22g, pulp concentration 2%;

[0037] Polyester fiber: fiber length 5mm, fineness 0.6dtex;

[0038] Crosslinking agent: polyethyleneimine (PEI), concentration 1.5%, crosslinking temperature 70°C, treatment time 45 minutes;

[0039] Ultrasonic treatment: power 350W, treatment time 7 minutes;

[0040] The preparation process is as follows:

[0041] 1) Mix bamboo fiber pulp and jute pulp at a mass ratio of 50:50 and perform ultrasonic dispersion treatment; 2) Add polyester fiber to the mixed pulp at a ratio of 40:60; 3) Add polyethyleneimine crosslinking agent, set the crosslinking temperature to 70°C, and the treatment time to 45 minutes; 4) Form using the rotary screen forming method, and obtain carbon-free solid electrolytic capacitor paper after pressing and drying.

[0042] Example 2

[0043] Bamboo fiber pulp: freeness 20°SR, wet weight 28g, pulp concentration 2%;

[0044] Manila hemp pulp: freeness 17°SR, wet weight 26g, pulp concentration 2%;

[0045] Polyester fiber: fiber length is 6mm, fineness is 0.8dtex;

[0046] Crosslinking agent: pentylene glycol, concentration 2%, crosslinking temperature 75°C, treatment time 40 minutes;

[0047] Ultrasonic treatment: 400W power, 8 minutes processing time;

[0048] The preparation process is as follows:

[0049] 1) Mix bamboo fiber pulp and Manila hemp pulp at a mass ratio of 50:50 and perform ultrasonic dispersion treatment; 2) Add polyester fiber to the mixed pulp at a ratio of 50:50; 3) Add pentylene glycol crosslinking agent and treat the crosslinking reaction at 75°C for 40 minutes; 4) Form using the cylinder molding method, and obtain carbon-free solid electrolytic capacitor paper after pressing and drying.

[0050] Example 3

[0051] Bamboo fiber pulp: freeness 22°SR, wet weight 30g, pulp concentration 2%;

[0052] Sisal pulp: freeness 19°SR, wet weight 27g, pulp concentration 2%;

[0053] Polyester fiber: fiber length 5mm, fineness 0.5dtex;

[0054] Crosslinking agent: polyacrylic acid, concentration 2%, crosslinking temperature 65°C, treatment time 50 minutes;

[0055] Ultrasonic treatment: 300W power, 9 minutes processing time;

[0056] The preparation process is as follows:

[0057] 1) Mix bamboo fiber pulp and sisal pulp at a mass ratio of 50:50 and perform ultrasonic dispersion treatment; 2) Add polyester fiber to the mixed pulp at a ratio of 50:50 and mix evenly; 3) Add polyacrylic acid crosslinking agent, the crosslinking reaction temperature is 65°C, and the treatment time is 50 minutes; 4) Form using the cylinder molding method, and obtain the final capacitor paper after pressing and drying.

[0058] Example 4

[0059] Bamboo fiber pulp: freeness 18°SR, wet weight 26g, pulp concentration 2%;

[0060] Jute pulp: freeness 16°SR, wet weight 24g, pulp concentration 2%;

[0061] Polyester fiber: fiber length is 6mm, fineness is 0.7dtex;

[0062] Crosslinking agent: polyethyleneimine (PEI), concentration 1.8%, crosslinking temperature 70°C, treatment time 45 minutes;

[0063] Ultrasonic treatment: 350W power, 8 minutes processing time;

[0064] The preparation process is as follows:

[0065] 1) Mix bamboo fiber pulp and jute pulp at a mass ratio of 60:40 and perform ultrasonic dispersion treatment; 2) Add polyester fiber and mix at a dry weight ratio of 40:60 to ensure uniform distribution; 3) Add polyethyleneimine crosslinking agent, and treat at a crosslinking reaction temperature of 70°C for 45 minutes; 4) Form using a rotary screen forming method, and obtain carbon-free solid electrolytic capacitor paper after pressing, drying, and slitting.

[0066] Example 5

[0067] Bamboo fiber pulp: freeness 20°SR, wet weight 28g, pulp concentration 2%;

[0068] Hemp pulp: freeness 17°SR, wet weight 26g, pulp concentration 2%;

[0069] Polyester fiber: fiber length 7mm, fineness 0.9dtex;

[0070] Crosslinking agent: polyurethane, concentration 2.5%, crosslinking temperature 75°C, treatment time 50 minutes;

[0071] Ultrasonic treatment: power 400W, treatment time 10 minutes;

[0072] The preparation process is as follows:

[0073] 1) Mix bamboo fiber pulp and hemp pulp at a mass ratio of 50:50 and perform ultrasonic dispersion treatment; 2) Add polyester fiber and mix at a dry weight ratio of 40:60; 3) Add polyurethane crosslinking agent to the mixed pulp, control the reaction temperature at 75°C, and treat for 50 minutes; 4) Form using the rotary screen forming method, and obtain carbon-free solid electrolytic capacitor paper after pressing, drying, and slitting.

[0074] Comparative Example 1

[0075] Bamboo fiber pulp: freeness 18°SR, wet weight 25g, pulp concentration 2%;

[0076] Jute pulp: freeness 16°SR, wet weight 22g, pulp concentration 2%;

[0077] Polyester fiber: fiber length 5mm, fineness 0.6dtex;

[0078] The preparation process is as follows:

[0079] 1) Add bamboo fiber pulp, jute pulp, and polyester fiber to the mixed pulp in a ratio of 20:20:60; 2) Form the paper using the rotary screen forming method, and obtain carbon-free solid electrolytic capacitor paper after pressing and drying.

[0080] Comparative Example 2

[0081] Bamboo fiber pulp: freeness 18°SR, wet weight 25g, pulp concentration 2%;

[0082] Polyester fiber: fiber length 5mm, fineness 0.6dtex;

[0083] Ultrasonic treatment: power 350W, treatment time 7 minutes;

[0084] The preparation process is as follows:

[0085] 1) The bamboo fiber pulp is ultrasonically dispersed; 2) The bamboo fiber pulp and polyester fiber are added to the mixed pulp in a ratio of 40:60; 3) The pulp is formed by rotary screen forming, and after pressing and drying, carbonization-free solid electrolytic capacitor paper is obtained.

[0086] Comparative Example 3

[0087] Jute pulp: freeness 16°SR, wet weight 22g, pulp concentration 2%;

[0088] Polyester fiber: fiber length 5mm, fineness 0.6dtex;

[0089] Ultrasonic treatment: power 350W, treatment time 7 minutes;

[0090] The preparation process is as follows:

[0091] 1) The jute pulp is ultrasonically dispersed; 2) The jute pulp and polyester fiber are added to the mixed pulp in a ratio of 40:60; 3) The pulp is formed by rotary screen forming, and after pressing and drying, carbonization-free solid electrolytic capacitor paper is obtained.

[0092] Comparative Example 4

[0093] Bamboo fiber pulp: freeness 18°SR, wet weight 25g, pulp concentration 2%;

[0094] Jute pulp: freeness 16°SR, wet weight 22g, pulp concentration 2%;

[0095] Polyester fiber: fiber length 5mm, fineness 0.6dtex;

[0096] The preparation process is as follows:

[0097] 1) Mix bamboo fiber pulp and jute pulp at a mass ratio of 50:50 and perform ultrasonic dispersion treatment; 2) Add polyester fiber to the mixed pulp at a ratio of 40:60; 3) Form using a rotary screen forming method, and obtain carbon-free solid electrolytic capacitor paper after pressing and drying.

[0098] Experimental Example 1: Monomer Adsorption Test

[0099] Objective: To evaluate the adsorption capacity and uniformity of conductive polymer monomers in electrolytic capacitor paper. Good adsorption ensures the uniform distribution of conductive monomers in the capacitor paper, thereby improving capacitor performance.

[0100] Test steps:

[0101] 1. Prepare samples:

[0102] Take a sample of electrolytic capacitor paper of a certain size (e.g., 5 cm × 5 cm); dry the sample to constant weight and record its dry weight.

[0103] 2. Preparation of monomer solution:

[0104] Prepare a 1.0 M conductive polymer monomer solution of polypyrrole conductive polymer monomer; dissolve the conductive monomer in an appropriate amount of solvent to ensure complete dissolution of the monomer.

[0105] 3. Immersion and adsorption:

[0106] Immerse the capacitor paper sample in the monomer solution for 12 hours to ensure sufficient time for monomer adsorption. The solution can be gently stirred with a stirring device to ensure that the monomer is evenly adsorbed onto the paper surface.

[0107] 4. Remove and wash:

[0108] Remove the sample from the solution and gently wash it with deionized water to remove any unadsorbed monomers from the surface; then dry the sample with absorbent paper or a lint-free cloth.

[0109] 5. Dry and weigh:

[0110] The washed sample was placed in an oven and dried at 60°C until constant weight was achieved. The dry weight was then recorded.

[0111] Adsorption capacity = Dry weight of paper sample after adsorption - Initial dry weight.

[0112] 6. Test Data

[0113]

[0114] Analysis: In the examples, the adsorption amount and adsorption uniformity of all samples were better than those of the comparative example, indicating that ultrasonic dispersion and chemical cross-linking treatment increased the contact area between the fiber and the monomer, thereby enhancing the adsorption and uniformity of the monomer.

[0115] Experimental Example 2

[0116] Objective: To evaluate the electrical stability of electrolytic capacitor paper in capacitors, primarily by testing leakage current to reflect its electrical performance. A low leakage current indicates that the electrolytic capacitor paper has good insulation and low electrical loss.

[0117] Test steps:

[0118] 1. Prepare samples:

[0119] Electrolytic capacitors are manufactured using non-carbonized solid aluminum electrolytic capacitor paper for both the anode and cathode plates. The capacitor dimensions and plate materials should meet the requirements of actual use.

[0120] 2. Assemble electrolytic capacitors:

[0121] Assemble the anode foil, cathode foil, and electrolytic capacitor paper into a capacitor according to the specified structure. Ensure tight contact between the electrolytic paper and the plates, avoiding air gaps.

[0122] 3. Apply voltage:

[0123] Connect the capacitor to a constant voltage power supply and apply the operating voltage (typically 1.2 to 1.5 times the capacitor's rated voltage). Set the voltage as needed; the operating voltage is typically 10-20V.

[0124] 4. Leakage current measurement:

[0125] Use an ammeter (such as a high-resistance meter or leakage current tester) to measure the leakage current of the capacitor after a voltage is applied; the measurement time can last for 1 hour to ensure that the capacitor is in a stable state.

[0126] 5. Record data:

[0127] Record the leakage current values ​​of the capacitor at different time periods. Calculate the average leakage current; the lower the leakage current, the more stable the electrical performance of the capacitor.

[0128]

[0129] 6. Analysis:

[0130] The leakage current in the examples was significantly lower than that in the comparative examples, and the stability during long-term use was better. This indicates that the electrical properties of the electrolytic capacitor paper were significantly improved through ultrasonic dispersion and chemical crosslinking treatment.

[0131] Experimental Example 3

[0132] Objective: To test the mechanical properties of carbon-free solid aluminum electrolytic capacitor paper, especially its tensile strength, tear resistance and wet stability, to ensure that the paper can withstand certain physical pressures during production and use.

[0133] Test steps:

[0134] 1. Prepare samples:

[0135] Cut electrolytic capacitor paper samples to standard sizes (e.g., 20cm × 5cm) for tensile testing; the paper samples should be kept dry, or wet testing can be performed as needed.

[0136] 1) Tensile strength test:

[0137] The tensile strength of electrolytic capacitor paper was tested using a tensile testing machine. The sample was clamped in the tensile testing machine fixture and stretched at a specified tensile speed (e.g., 50 mm / min). The maximum load at which the sample broke during the stretching process was recorded, and the tensile strength was calculated (unit: N / m). 2 ).

[0138] 2) Tear resistance test:

[0139] The paper sample was tested for tear resistance using a tear testing machine. Following the standard method (ASTM D5733), the paper sample was placed in the tear testing equipment, and the tear strength was measured. The tear energy of the sample during the tearing process was recorded, and the tear resistance was calculated.

[0140] 3) Wet mechanical property testing:

[0141] Electrolytic capacitor paper is immersed in water or other liquids for a certain period of time (e.g., 24 hours) to simulate a wet environment. Tensile strength and tear resistance under wet conditions are measured, and the differences in performance between wet and dry conditions are compared.

[0142] 2. Test Data

[0143] a) Tensile strength (unit: kN / m)

[0144]

[0145] Analysis: The tensile strength of the paper in the examples is significantly higher than that of the comparative examples. Especially in wet conditions, the paper in the examples exhibits better stability and tensile strength, adapting to humid environments or physical pressures during production.

[0146] b) Tear resistance (unit: J)

[0147]

[0148] Analysis: In the example, the higher tear strength demonstrates better durability and tear resistance, which is of great significance for the production and use of capacitors.

[0149] 4. Wet mechanical properties (wet stability test)

[0150]

[0151] Analysis: The wet tensile strength and wet tear strength of the examples are significantly higher than those of the comparative examples, indicating that the paper can still maintain good mechanical properties in a wet environment after crosslinking and ultrasonic dispersion treatment.

[0152] The above is a description of embodiments of the present invention. Through the above description of the disclosed embodiments, those skilled in the art will be able to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novelty disclosed herein.

Claims

1. A method for preparing carbon-free solid aluminum electrolytic capacitor paper, using bamboo fiber, jute pulp, and polyester fiber as main raw materials, characterized in that: 1) Add bamboo fiber pulp to hemp pulp and disperse the pulp using ultrasonic treatment. The ultrasonic treatment power is 200-500W and the treatment time is 5-10 minutes. 2) Add polyester fiber to the bamboo fiber pulp treated in step 1) and mix. The dry weight ratio of bamboo fiber, pulp and polyester fiber is 20-30%: 20-40%: 30-60%. 3) Add a chemical crosslinking agent for chemical crosslinking treatment. The chemical crosslinking agent is a polyhydroxy compound or a polymer crosslinking agent. The concentration of the crosslinking agent is 1%-5%, the crosslinking temperature is 60-80℃, and the treatment time is 30-60 minutes. 4) The mixed fiber slurry is formed by the rotary screen forming method. The formed capacitor paper is then pressed and dried to obtain low-density, carbon-free solid electrolytic capacitor paper.

2. The method of claim 1, wherein, In step 1), the hemp pulp is selected from one or more of the following: sisal pulp, Manila hemp pulp, jute pulp, hemp pulp, and flax pulp.

3. The method of claim 1, wherein, In step 1), the beating degree of bamboo fiber pulp and hemp pulp is 10-30°SR, and the wet weight is 15-30g.

4. The method of claim 1, wherein, The polyester fiber has a length of 0.2-1.5 dtex and a length of 3-10 mm.

5. The method of claim 1, wherein, The paper is dried at 70-90°C, and the tightness of the dried paper is 0.2-0.5 g / cm 3 .

6. The method of claim 1, wherein, In step 2), a thickener was also added to the mixed fiber pulp. The amount of thickener added was 1.0-5.0% of the dry weight of the paper.

7. The method of claim 6, wherein, The thickener is one or more of rosin, gum arabic, xanthan gum, carrageenan, and polyvinyl alcohol.

8. The carbon-free solid aluminum electrolytic capacitor paper prepared by the method of any one of claims 1-7.

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