Anti-aging electrolytic capacitor paper and preparation method thereof

Abstract

According to the anti-aging electrolytic capacitor paper and the preparation method thereof, the capacitor paper is mainly composed of wood pulp fibers, an antioxidant and an anti-acid agent are added at the same time, the anti-acid agent is an amino silane coupling agent, the upper surface and the lower surface are coated with nano cellulose layers at the same time, the binding capacity is high, the thermal stability and oxidation resistance are improved through nano silicon dioxide and the antioxidant, and the service life of the capacitor paper is prolonged. The stability of the coating is improved; meanwhile, the wood pulp fiber layer is also protected. The prepared electrolytic capacitor paper is excellent in aging resistance, the preparation method of the capacitor paper is simple, and the service life of the prepared capacitor paper can be remarkably prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrolytic capacitors, and particularly relates to an anti-aging electrolytic capacitor paper and a preparation method thereof. Background Art

[0002] Electrolytic capacitor paper is an essential and important material for the production of aluminum electrolytic capacitors. As the liner material of electrolytic capacitors, it plays the roles of adsorbing working electrolyte, isolating the positive and negative foil sheets, and preventing short circuit between the two poles. Along with the operation of aluminum electrolytic capacitors until the end of their service life, it has an important impact on the quality of aluminum electrolytic capacitors, and thus plays a decisive role in the performance of aluminum electrolytic capacitors. With the rapid development of the electronic information industry, the requirements for the quality, reliability, and long life of capacitors are getting higher and higher. However, as the usage time of capacitors increases, the performance of the key component, capacitor paper, deteriorates due to aging problems, resulting in capacitor failure.

[0003] Chinese patent document CN110202883A discloses an anti-aging capacitor diaphragm and a preparation method thereof. The capacitor diaphragm is made of the following raw materials in parts by weight: 30 - 40 parts of polyethylene fiber, 15 - 20 parts of ES fiber, 10 - 12 parts of basalt fiber powder, 5 - 10 parts of polycarbonate fiber, 5 - 7 parts of silica powder, 3 - 5 parts of cerium dioxide, 6 - 8 parts of polyurea, 4 - 6 parts of 2,2 - methylenebis(4 - methyl - 6 - tert - butylphenol), 2 - 4 parts of N - phenyl - N - cyclohexyl - p - aniline, 0.3 - 0.5 parts of coupling agent, 1 - 2 parts of plasticizer, and 1 - 2 parts of dispersant. The main component of the anti-aging capacitor diaphragm of this patent is chemical fiber.

[0004] Wood pulp fiber has the advantages of good liquid absorption, low thermal shrinkage rate, easy fibrillation, high breakdown resistance, and low price, and is widely used in the preparation of electrolytic capacitor paper. Therefore, how to develop an anti-aging capacitor paper with wood pulp fiber as the main fiber and meet the application requirements of capacitor reliability and long life is particularly important. Summary of the Invention

[0005] In order to overcome the problems in the prior art, the present invention provides an anti-aging electrolytic capacitor paper and a preparation method thereof. The main fiber of the capacitor paper is wood pulp fiber, which solves the problems of poor anti-aging performance and short life of the existing capacitor paper.

[0006] In order to solve the above technical problems, the technical solution proposed by the present invention is as follows: The present invention provides an anti-aging electrolytic capacitor paper, which is composed of a wood pulp fiber layer and nano fiber layers located on both sides of the wood pulp fiber layer. The wood pulp fiber layer is prepared from wood pulp fiber, antioxidant, and anti-acid agent. The nano fiber layer is composed of nano cellulose, nano silica, and antioxidant. The anti-acid agent is an amino silane coupling agent.

[0007] Wood pulp fiber belongs to cellulose fiber. A large number of hydroxyl groups are contained in cellulose. The cellulose molecules can form hydrogen bonds. The more hydrogen bonds are formed between molecules, the greater the binding force between cellulose molecules, and the higher the mechanical strength of the capacitor paper. However, the hydroxyl groups in cellulose molecules are easily oxidized to form organic acids. The generated organic acids will cause the cellulose to undergo hydrolysis reactions, resulting in the cleavage of glycosidic bonds (or oxygen bridges), shortening the cellulose molecular chains, reducing the intermolecular force, decreasing the mechanical strength of the capacitor paper, and being easily broken down during use, causing the capacitor to fail. Therefore, in the present invention, antioxidants and anti-acids are added to the wood pulp to improve the aging resistance of the capacitor paper. The antioxidant inhibits the oxidation reaction of hydroxyl groups in cellulose, and the anti-acid inhibits the cleavage reaction of glycosidic bonds (or oxygen bridges).

[0008] A nanocellulose coating is coated on the upper and lower surfaces of the capacitor paper, which is composed of cellulose nanofibers, nano-silica, and antioxidants. Due to the large specific surface area, cellulose nanofibers can form a large number of hydrogen bonds, with strong binding force, and can be firmly combined with wood pulp fibers; due to its ultra-fine nano-scale size, uniform particle size, and strong surface adsorption capacity, etc., nano-silica can improve the anti-aging property, anti-ultraviolet ability, and thermal stability of cellulose fibers. At the same time, antioxidants are added to improve the antioxidant property of the capacitor paper.

[0009] In the present invention, the amino-silane coupling agent has functional organic functional groups and hydrolyzable alkoxy groups, and will be fully adsorbed on the surface of wood pulp fibers. On the one hand, it can protect the hydroxyl groups on the fiber surface, and on the other hand, it can neutralize the organic acids in the electrolytic capacitor paper.

[0010] As an alternative embodiment, in the electrolytic capacitor paper provided by the present invention, the antioxidant A is selected from one or more of 2,6-di-tert-butylcresol antioxidant, hindered phenol-pentaerythritol ester composite antioxidant, hindered phenol-isocyanuric acid ester composite antioxidant, and hindered phenol-phosphite composite antioxidant.

[0011] As an alternative embodiment, in the electrolytic capacitor paper provided by the present invention, the anti-acid is selected from one or more of mono-amino-silane coupling agent, bis-amino-silane coupling agent, or tris-amino-silane coupling agent.

[0012] As an alternative embodiment, in the electrolytic capacitor paper provided by the present invention, the mass percentages of the components in the wood pulp fiber layer are: wood pulp fiber 80 - 98%, antioxidant 1 - 10%, and anti-acid 1% - 10%.

[0013] As an alternative embodiment, in the electrolytic capacitor paper provided by the present invention, the percentages of the components in the nanofiber layer are nanofibrillated cellulose 90 - 98%, nano-silica 1 - 5%, and antioxidant 1 - 5%.

[0014] As an alternative embodiment, in the electrolytic capacitor paper provided by the present invention, the basis weight of the electrolytic capacitor is 20-40 g / m 2 , the basis weight of the wood pulp fiber layer is 10-38 g / m 2 , and the basis weight of the nanofiber coating is 1-5 g / m 2 .

[0015] As an alternative embodiment, in the electrolytic capacitor paper provided by the present invention, the wood pulp used to prepare the wood pulp fiber is selected from softwood pulp or hardwood pulp, the beating degree is 30-95°SR, and the average fiber length is 0.6-2.0 mm.

[0016] As an alternative embodiment, in the electrolytic capacitor paper provided by the present invention, the diameter of the nanocellulose is 5-80 nm and the length is 50-600 nm; the particle size of the nano-silica is 10-30 nm.

[0017] Based on the same technical concept, the present invention also provides a method for preparing the above-mentioned aging-resistant electrolytic capacitor paper, which includes the following steps: S1. Grind the wood pulp fiber and control the average fiber length and beating degree.

[0018] S2. Immerse the wood pulp fiber obtained in step S1 in an amino silane coupling agent-ethanol solution, and obtain surface-modified wood pulp fiber after drying.

[0019] S3. Prepare an aqueous solution of the modified wood pulp fiber obtained in step S2, add an antioxidant and stir evenly to obtain a slurry.

[0020] S4. Form the slurry obtained in step S3 through a capacitor paper forming device, and obtain a wood pulp fiber layer through pressing, drying, curling, and slitting.

[0021] S5. Prepare a nanocellulose solution, then add nano-silica and an antioxidant and stir evenly for later use. Coat the upper and lower surfaces of the wood pulp fiber layer with a nanofiber layer through a coating device to obtain the aging-resistant electrolytic capacitor paper.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) In the present invention, the main component of the capacitor paper is wood pulp fiber, and an antioxidant and an anti-acid agent are added at the same time. The antioxidant inhibits the oxidation reaction of hydroxyl groups in cellulose, and the anti-acid agent inhibits the cleavage reaction of glycosidic bonds (or oxygen bridges); in addition, a nanocellulose layer is coated on the upper and lower surfaces, with strong binding ability. Nano-silica and the antioxidant improve the thermal stability and antioxidant properties, protect the wood pulp fiber layer while improving the coating stability, and the prepared electrolytic capacitor paper has excellent aging resistance.

[0023] (2) The traditional antacid is magnesium hydroxide, which belongs to inorganic powder and has problems of uneven dispersion and poor binding force with fibers. The present invention adds a new antacid, namely amino silane coupling agent, which is easy to disperse and will be fully adsorbed on the surface of wood pulp fibers.

[0024] (3) The preparation method of the capacitor paper in the present invention is simple, and the prepared capacitor paper can significantly improve the service life. Specific Embodiments

[0025] For the convenience of understanding the present invention, the following will describe the present invention more comprehensively and carefully in combination with the specification and preferred embodiments, but the protection scope of the present invention is not limited to the following specific embodiments.

[0026] Unless otherwise defined, all professional terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present invention.

[0027] Unless otherwise specifically stated, various raw materials, reagents, instruments and equipment used in the present invention can be obtained through market purchase or can be prepared by existing methods.

[0028] Synthesis method of amino silane coupling agent: (1) Synthesis of chlorohydrocarbyl chlorosilane: Add a certain amount of methyltrichlorosilane and a small amount of catalyst into a three-necked flask equipped with a thermometer and a fractionating column, heat it to vaporize, introduce dry chlorine gas into the three-necked flask, and irradiate it with a fluorescent lamp or an ultraviolet lamp. During the reaction process, the bottom temperature gradually rises until the boiling point of the product; the top temperature is maintained near the boiling point of the raw material. After the reaction is completed, fractionate and take the fraction at 112 - 120 °C.

[0029]

[0030] (2) Alcoholysis reaction: Put a certain amount of chlorosilane into a four-necked flask equipped with a straight condenser (filled with porcelain rings) - constant pressure funnel, thermometer and N 2 bottom tube, heat it to a certain temperature, then dropwise add ethanol, bubble to drive off acid, and keep normal reflux after dropping. Determine the end point of the reaction by measuring the chlorine content.

[0031]

[0032] (3) Amination reaction: Monoamino: Add a certain amount of ClCH 2 Si(OCH 3 ) 3 and liquid NH 3 into an autoclave, heat the autoclave, react at 100 °C for 12 h, the autoclave pressure is as high as 6.2 MPa, and the product is obtained after fractionation.

[0033] Diamino: Ethylenediamine was placed in a three-necked flask equipped with a condenser, a constant pressure funnel, and a thermometer, and heated under reflux. ClCH was dropped in from the funnel. 2 Si(OCH 3 ) 3 , and the reaction was refluxed for 5 h, then cooled and the excess ethylenediamine was distilled off.

[0034] Triamino: A certain amount of diethylenetriamine was placed in a three-necked flask equipped with a condenser, a stirrer, and a thermometer. ClCH 2 Si(OCH 3 ) 3 was added under stirring, and the mixture was heated under reflux at 200 - 220 °C for 5.5 h, then cooled and filtered, and the filtrate was distilled under reduced pressure.

[0035]

[0036] Example 1 A method for preparing electrolytic capacitor paper, comprising the following steps: (1) Pulping softwood pulp or hardwood pulp fibers.

[0037] (2) The pulp fibers prepared in (1) were impregnated in the above-prepared amino-silane coupling agent - ethanol solution for 10 min, then dried to obtain surface-modified pulp fibers. The modified pulp fibers were formulated into an aqueous solution of a certain concentration, and an antioxidant was added. After stirring evenly, a slurry was obtained.

[0038] (3) The slurry in (2) was formed by a capacitor paper forming device, and after pressing, drying, curling, and slitting, a pulp fiber layer was obtained.

[0039] (4) A nano-cellulose solution was prepared, and nano-silica and an antioxidant were added and stirred evenly for later use. The upper and lower surfaces of the pulp fiber layer were coated with a nano-fiber layer through a coating device to obtain anti-aging electrolytic capacitor paper.

[0040] In the electrolytic capacitor paper of this example, the total basis weight was designed to be 40 g / m 2 , among which the basis weight of the pulp fiber layer was 38 g / m 2 , the beating degree was 30 °SR, and the mass fraction ratio of pulp fibers, monoamino-silane coupling agent, and hindered phenol - pentaerythritol ester composite antioxidant (Antioxidant 1010, BASF) was 80:10:10. The basis weight of the nano-fiber coating on the upper surface was 1 g / m 2 , the basis weight of the nano-fiber coating on the lower surface was 1 g / m 2 , and the mass fraction ratio of nano-cellulose, nano-silica, and Antioxidant 1010 was 90:5:5, among which the diameter of nano-cellulose was 5 nm and the length was 50 nm, and the particle size of nano-silica was 50 nm.

[0041] Example 2 The preparation method is the same as that of Example 1, except that: For the electrolytic capacitor paper in this example, the total basis weight is designed to be 20 g / m 2 , where the basis weight of the wood pulp fiber layer is 10 g / m 2 , the beating degree is 30°SR, and the mass fraction ratio of wood pulp fiber, bis - amino silane coupling agent, and hindered phenol - isocyanurate composite antioxidant (antioxidant 3114, BASF) is 98:1:1. The basis weight of the upper surface nanofiber coating is 5 g / m 2 , and the basis weight of the lower surface nanofiber coating is 5 g / m 2 , and the mass fraction ratio of nanocellulose, nano - silica, and antioxidant 3114 is 98:1:1, where the diameter of nanocellulose is 40 nm and the length is 300 nm, and the particle size of nano - silica is 20 nm.

[0042] Example 3 The preparation method is the same as that of Example 1, except that: For the electrolytic capacitor paper in this example, the total basis weight is designed to be 30 g / m 2 , where the basis weight of the wood pulp fiber layer is 24 g / m 2 , the beating degree is 60°SR, and the mass fraction ratio of wood pulp fiber, tris - amino silane coupling agent, and hindered phenol - phosphite composite antioxidant (antioxidant 225, BASF) is 90:5:5. The basis weight of the upper surface nanofiber coating is 3 g / m 2 , and the basis weight of the lower surface nanofiber coating is 3 g / m 2 , and the mass fraction ratio of nanocellulose, nano - silica, and antioxidant 225 is 92:4:4, where the diameter of nanocellulose is 80 nm and the length is 600 nm, and the particle size of nano - silica is 30 nm.

[0043] Example 4 The preparation method is the same as that of Example 1, except that: For the electrolytic capacitor paper in this example, the total basis weight is designed to be 40 g / m 2 , where the basis weight of the wood pulp fiber layer is 38 g / m 2 , the beating degree is 30°SR, and the mass fraction ratio of wood pulp fiber, bis - amino silane coupling agent, and hindered phenol - isocyanurate composite antioxidant (antioxidant 3114, BASF) is 90:5:5. The basis weight of the upper surface nanofiber coating is 1 g / m 2 , and the basis weight of the lower surface nanofiber coating is 1 g / m 2 , and the mass fraction ratio of nanocellulose, nano - silica, and antioxidant 3114 is 98:1:1, where the diameter of nanocellulose is 40 nm and the length is 300 nm, and the particle size of nano - silica is 20 nm.

[0044] Example 5 The preparation method is the same as that of Example 1, except that: For the electrolytic capacitor paper in this example, the total basis weight is designed to be 40 g / m 2 , and the basis weight of the wood pulp fiber layer is 38 g / m 2 , the beating degree is 30°SR, and the mass fraction ratio of wood pulp fiber, triaminosilane coupling agent, and hindered phenol-phosphite composite antioxidant (Antioxidant 225, BASF) is 98:1:1. The basis weight of the nanofiber coating on the upper surface is 1 g / m 2 , and the basis weight of the nanofiber coating on the lower surface is 1 g / m 2 , and the mass fraction ratio of nanocellulose, nanosilica, and Antioxidant 225 is 92:4:4, where the diameter of nanocellulose is 80 nm, the length is 600 nm, and the particle size of nanosilica is 30 nm.

[0045] Example 6 The preparation method is the same as that of Example 1, except that: For the electrolytic capacitor paper in this example, the total basis weight is designed to be 20 g / m 2 , and the basis weight of the wood pulp fiber layer is 10 g / m 2 , the beating degree is 95°SR, and the mass fraction ratio of wood pulp fiber, monoaminosilane coupling agent, and hindered phenol-pentaerythritol ester composite antioxidant (Antioxidant 1010, BASF) is 80:10:10. The basis weight of the nanofiber coating on the upper surface is 5 g / m 2 , and the basis weight of the nanofiber coating on the lower surface is 5 g / m 2 , and the mass fraction ratio of nanocellulose, nanosilica, and Antioxidant 1010 is 90:5:5, where the diameter of nanocellulose is 5 nm, the length is 50 nm, and the particle size of nanosilica is 10 nm.

[0046] Example 7 The preparation method is the same as that of Example 1, except that: For the electrolytic capacitor paper in this example, the total basis weight is designed to be 20 g / m 2 , and the basis weight of the wood pulp fiber layer is 10 g / m 2 , the beating degree is 95°SR, and the mass fraction ratio of wood pulp fiber, triaminosilane coupling agent, and hindered phenol-phosphite composite antioxidant (Antioxidant 225, BASF) is 90:5:5. The basis weight of the nanofiber coating on the upper surface is 5 g / m 2 , and the basis weight of the nanofiber coating on the lower surface is 5 g / m 2 , and the mass fraction ratio of nanocellulose, nanosilica, and Antioxidant 225 is 92:4:4, where the diameter of nanocellulose is 80 nm, the length is 600 nm, and the particle size of nanosilica is 30 nm.

[0047] Example 8 The preparation method is the same as that of Example 1, except that: For the electrolytic capacitor paper in this example, the total basis weight is designed to be 30 g / m 2 , among which the basis weight of the wood pulp fiber layer is 24 g / m 2 , the beating degree is 60°SR, and the mass fraction ratio of wood pulp fiber, monoamino silane coupling agent, and hindered phenol-pentaerythritol ester compound antioxidant (Antioxidant 1010, BASF) is 98:1:1. The basis weight of the nanofiber coating on the upper surface is 3 g / m 2 , and the basis weight of the nanofiber coating on the lower surface is 3 g / m 2 , and the mass fraction ratio of nanocellulose, nano-silica, and Antioxidant 1010 is 90:5:5, among which the diameter of nanocellulose is 5 nm and the length is 50 nm, and the particle size of nano-silica is 10 nm.

[0048] Example 9 The preparation method is the same as that of Example 1, except that: For the electrolytic capacitor paper in this example, the total basis weight is designed to be 30 g / m 2 , among which the basis weight of the wood pulp fiber layer is 24 g / m 2 , the beating degree is 60°SR, and the mass fraction ratio of wood pulp fiber, diamino silane coupling agent, and hindered phenol-isocyanurate compound antioxidant (Antioxidant 3114, BASF) is 80:10:10. The basis weight of the nanofiber coating on the upper surface is 3 g / m 2 , and the basis weight of the nanofiber coating on the lower surface is 3 g / m 2 , and the mass fraction ratio of nanocellulose, nano-silica, and Antioxidant 3114 is 98:1:1, among which the diameter of nanocellulose is 40 nm and the length is 300 nm, and the particle size of nano-silica is 20 nm.

[0049] Comparative Example 1 The wood pulp with a beating degree of 60°SR is wet-formed by a capacitor paper forming device, and after pressing, drying, curling, and slitting, the electrolytic capacitor paper is obtained. The basis weight of the electrolytic capacitor paper is 30 g / m 2 , and then the performance of the capacitor paper is detected.

[0050] Comparative Example 2 The wood pulp with a beating degree of 60°SR is prepared into an aqueous solution with a certain concentration, and a hindered phenol-phosphite compound antioxidant (Antioxidant 225, BASF) is added and stirred evenly. The mass fraction ratio of wood pulp fiber to Antioxidant 225 is 95:5. The obtained slurry is wet-formed by a capacitor paper forming device, and after pressing, drying, curling, and slitting, the electrolytic capacitor paper is obtained. The basis weight of the electrolytic capacitor paper is 30 g / m 2 , and then the performance of the capacitor paper is detected.

[0051] Comparative Example 3 The beating degree of 60°SR was impregnated in a triaminosilane coupling agent - ethanol solution for 10 min, then dried, and then formulated into an aqueous solution with a certain concentration and stirred evenly. The mass fraction ratio of wood pulp fiber to triaminosilane coupling agent was 95:5. The obtained slurry was wet - formed by a capacitor paper forming device, and then electrolytic capacitor paper was obtained through pressing, drying, curling, and slitting. The basis weight of the electrolytic capacitor paper was 30 g / m 2 Then, the performance of the capacitor paper was detected.

[0052] Comparative Example 4 The beating degree of 60°SR was impregnated in a triaminosilane coupling agent - ethanol solution for 10 min, then dried, and then formulated into an aqueous solution with a certain concentration. A hindered phenol - phosphite composite antioxidant (Antioxidant 225, BASF) was added and stirred evenly. The mass fraction ratio of wood pulp fiber, triaminosilane coupling agent, and Antioxidant 225 was 90:5:5. The obtained slurry was wet - formed by a capacitor paper forming device, and then electrolytic capacitor paper was obtained through pressing, drying, curling, and slitting. The basis weight of the electrolytic capacitor paper was 30 g / m 2 Then, the performance of the capacitor paper was detected.

[0053] Comparative Example 5 The total basis weight of this example was designed to be 30 g / m 2 Among them, the basis weight of the wood pulp fiber layer was 24 g / m 2 . The wood pulp with a beating degree of 60°SR was formulated into an aqueous solution with a certain concentration. A hindered phenol - phosphite composite antioxidant (Antioxidant 225, BASF) was added and stirred evenly. The mass fraction ratio of wood pulp fiber to Antioxidant 225 was 95:5. The obtained slurry was wet - formed by a capacitor paper forming device, and then electrolytic capacitor paper was obtained through pressing, drying, curling, and slitting. Then, the upper and lower surfaces of the wood pulp fiber layer were coated with a nanofiber layer by a coating device to obtain an anti - aging electrolytic capacitor paper. The basis weight of the upper - surface nanofiber coating was 3 g / m 2 The basis weight of the upper - surface nanofiber coating was 3 g / m 2 , and the mass fraction ratio of nanocellulose, nano - silica, and Antioxidant 225 was 92:4:4. Among them, the diameter of nanocellulose was 80 nm and the length was 600 nm, and the particle size of nano - silica was 30 nm., Comparative Example 6 The total basis weight of this example was designed to be 30 g / m 2 Among them, the basis weight of the wood pulp fiber layer was 24 g / m 2。After impregnating the beating degree of 60°SR in a triaminosilane coupling agent-ethanol solution for 10 min, it was dried and then formulated into an aqueous solution with a certain concentration and stirred evenly, where the mass fraction ratio of wood pulp fiber to triaminosilane coupling agent was 95:5. The obtained slurry was wet-formed through a capacitor paper forming device, and then electrolytic capacitor paper was obtained through pressing, drying, curling, and slitting. Then, a nanofiber layer was coated on the upper and lower surfaces of the wood pulp fiber layer through a coating device to obtain aging-resistant electrolytic capacitor paper, where the basis weight of the nanofiber coating on the upper surface was 3 g / m 2 , the basis weight of the nanofiber coating on the upper surface was 3 g / m 2 , and the mass fraction ratio of nanocellulose, nano-silica, and antioxidant 225 was 92:4:4, where the diameter of nanocellulose was 80 nm and the length was 600 nm, and the particle size of nano-silica was 30 nm.

[0054] The electrolytic capacitor paper of the comparative example and the electrolytic capacitor paper of the example were taken out after aging in an oven at 145°C for 144 h, and then the capacitor paper before and after heat aging treatment was placed at 23°C and 50% RH for 24 h under constant temperature and humidity for performance testing. The test results are shown in Table 1. The tensile strength of the electrolytic capacitor paper was tested, and the test standard was GB / T 12914-2018, and the tensile strength retention rate of the aging-resistant capacitor paper was calculated. The calculation formula is as follows:

[0055] Where S 0 is the tensile strength of the capacitor paper before aging test; S 1 is the tensile strength of the capacitor paper after aging test.

[0056] The detection results are shown in Table 1 below.

[0057] Table 1: Performance of electrolytic capacitor paper in the example and the comparative example

[0058] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific implementation of the present invention is limited to these descriptions. For those of ordinary skill in the art to which the present invention pertains, without departing from the concept of the present invention, several simple deductions or substitutions can still be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. An aging-resistant electrolytic capacitor paper, characterized in that: The electrolytic capacitor paper consists of a wood pulp fiber layer and nano fiber layers located on both sides of the wood pulp fiber layer, the wood pulp fiber layer is prepared from wood pulp fiber, an antioxidant and an antacid, the nano fiber layer consists of nano cellulose, nano silicon dioxide and an antioxidant, and the antacid is an aminosilane coupling agent.

2. The aging-resistant electrolytic capacitor paper according to claim 1, characterized in that: The antioxidant is selected from one or more of 2,6-di-tert-butylcresol antioxidant, hindered phenol-pentaerythritol ester composite antioxidant, hindered phenol-isocyanurate composite antioxidant, and hindered phenol-phosphite composite antioxidant.

3. The aging-resistant electrolytic capacitor paper according to claim 1, characterized in that: The antacid is selected from one or more of a monoaminosilane coupling agent, a bisaminosilane coupling agent or a triaminosilane coupling agent.

4. The aging-resistant electrolytic capacitor paper according to claim 1, characterized in that: The mass percentages of the components in the wood pulp fiber layer are: 80-98% wood pulp fiber, 1-10% antioxidant, and 1%-10% antacid.

5. The aging-resistant electrolytic capacitor paper according to claim 1, characterized in that: The percentages of the components in the nanofiber layer are: 90-98% nanocellulose, 1-5% nano silicon dioxide, and 1-5% antioxidant.

6. The aging-resistant electrolytic capacitor paper according to claim 1, characterized in that: The electrolytic capacitor has a weight of 20-40 g / m 2 The wood pulp fiber layer has a quantitative value of 10-38 g / m 2 The nanofiber coating is 1-5 g / m 2 .

7. The aging-resistant electrolytic capacitor paper according to claim 1, characterized in that: The wood pulp used to prepare the wood pulp fiber is selected from coniferous wood pulp or broadleaf wood pulp, with a beating degree of 30-95° SR and an average fiber length of 0.6-2.0 mm.

8. The aging-resistant electrolytic capacitor paper according to claim 1, characterized in that: The diameter of the nanocellulose is 5-80nm and the length is 50-600nm; the particle size of the nano silicon dioxide is 10-30nm.

9. The method for preparing aging-resistant electrolytic capacitor paper according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1, refining wood pulp fibers to control the average fiber length and beating degree; S2, immersing the wood pulp fiber obtained in step S1 in an aminosilane coupling agent-ethanol solution, and drying to obtain surface-modified wood pulp fiber; S3, preparing the modified wood pulp fiber obtained in step S2 into an aqueous solution, adding an antioxidant and stirring evenly to obtain a slurry; S4, forming the slurry obtained in step S3 through a capacitor paper forming device, and obtaining a wood pulp fiber layer through pressing, drying, curling, and cutting; S5, preparing a nanocellulose solution, then adding nano-silicon dioxide and an antioxidant, stirring evenly and setting aside, coating the upper and lower surfaces of the wood pulp fiber layer with a nanofiber layer by a coating device, and obtaining an aging-resistant electrolytic capacitor paper.

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