Preparation method of high compressive electrolytic capacitor paper

Abstract

The present invention belongs to the technical field of special paper preparation, and particularly relates to a preparation method of a high-compressive electrolytic capacitor paper. By weight, the electrolytic capacitor paper comprises the following raw materials: 50-60 parts of modified insulating wood pulp fibers; 30-40 parts of porous chemical fibers; 20-30 parts of tencel fibers; 5-10 parts of water-soluble PVA fibers; 3-8 parts of an auxiliary agent. The high-compressive electrolytic capacitor paper prepared by the preparation method of the present invention has the advantages of high liquid absorption capacity, high mechanical strength and compressive strength, and is not easily broken down.

Description

Technical Field

[0001] The present invention belongs to the technical field of special paper preparation, and particularly relates to a preparation method of high compressive electrolytic capacitor paper. Background Art

[0002] Electrolytic capacitors are one of the important components in the electronics industry. In addition to filtering, decoupling, and signal coupling in circuits, they also play special roles in special circuits such as correction circuits, power supply circuits, and AC motor starting circuits. They are widely used in the automotive industry, security industry, medical electronics, computers, TVs, electronic toys, and industrial control fields, and are one of the indispensable components in the power supplies of various electronic products. Structurally, an electrolytic capacitor has a layer of paper sandwiched between two metal foils. After winding, it is impregnated or dropped with electrolyte and then installed in a housing. For such electrolytic capacitors, the paper wound therein is electrolytic capacitor paper. Electrolytic capacitor paper is one of the three key materials that make up an electrolytic capacitor. It is used between the cathode and anode of an electrolytic capacitor as a gasket material for the electrolytic capacitor, playing the roles of adsorbing the working electrolyte, isolating the positive and negative foil sheets, and preventing short circuits between the two poles. It has an important impact on the quality of the electrolytic capacitor throughout its service life until the end of the electrolytic capacitor's life.

[0003] Electrolytic capacitor paper directly affects the four main indicators of electrolytic capacitors: loss, leakage current, capacitance, and rated voltage. Generally, electrolytic capacitor paper should meet the following requirements: First, it should have high purity, and strict control must be imposed on impurities that affect the performance of the electrolyte and electrode foil, such as various acid radical ions and conductive metal ions, etc. This is also the main sign that differentiates electrolytic capacitor paper from other papers. Second, the paper quality should be uniform, with uniform thickness and tightness, and uniform fiber arrangement. At the same time, there should be no paper defects such as holes and fiber bundles. Third, it should have necessary mechanical and electrical strengths. Fourth, it should have good impregnation and retention properties for the electrolyte, which is absorption in terms of indicators. Fifth, when forming a complex with the electrolyte, it should have low impedance in the temperature range from low to high.

[0004] Among the many performance and quality requirements of electrolytic capacitor paper, to ensure the liquid absorption capacity of the paper and reduce the impedance, it is necessary to make the tightness and thickness of the paper as low as possible; at the same time, fibers with good hygroscopicity and strong moisture retention properties should be selected to enable the paper to adsorb as much electrolyte as possible; however, papers with low tightness, thin thickness, and good hygroscopicity generally have low strength and are prone to breakage during winding, significantly increasing the short - circuit rate of capacitors or batteries; at the same time, papers with low tightness and thin thickness are easily broken down under the action of an electric field and have low compressive strength.

[0005] Especially today when electrolytic capacitors are developing rapidly towards high capacitance and small size, the breakdown voltage of electrolytic capacitor paper is also increasing rapidly. How to balance the relationship between the voltage resistance performance and other properties of electrolytic capacitor paper and provide a high-voltage-resistant electrolytic capacitor paper on the premise of ensuring that the electrolytic capacitor paper meets the basic requirements is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0006] The purpose of the present invention is to provide a preparation method of a high-voltage-resistant electrolytic capacitor paper for the above-mentioned existing technical problems.

[0007] In the present technical solution, a preparation method of a high-voltage-resistant electrolytic capacitor paper is provided. Calculated by weight parts, the electrolytic capacitor paper comprises the following raw materials:

[0008]

[0009] Further, the auxiliary agent comprises 30-40% of AKD, 20-30% of polyethylene oxide, and the balance is polyacrylamide.

[0010] Further, the preparation process of the modified insulating wood pulp fiber is as follows:

[0011] (1) Soaking: Add the insulating wood pulp fiber into an appropriate amount of water and soak it at room temperature for 3-5 h;

[0012] (2) Alkali treatment: Place the water-soaked insulating wood pulp fiber in an alkali solution and soak it at 60-90 °C with stirring for 1-3 h;

[0013] (3) Acid treatment: Place the alkali-treated insulating wood pulp fiber in an acid solution and soak it at 60-90 °C with stirring for 0.5-1 h, then rinse it with tap water until neutral, and then put it into an oven at 100-120 °C to dry;

[0014] (4) Post-treatment: First, place the acid-treated insulating wood pulp fiber in a coupling agent solution, mix it at room temperature with stirring for 10-20 min, and then put it into an oven at 100-120 °C to dry; then dissolve 0.5-1% of styrene-butadiene-styrene block copolymer by weight of the insulating wood pulp fiber in an appropriate amount of organic solvent, stir until dissolved, mix it with the insulating wood pulp fiber treated with the coupling agent, mix it at room temperature with stirring for 10-20 min, and then put it into an oven at 100-120 °C to dry again to obtain the modified insulating wood pulp fiber.

[0015] Further, the alkali solution is a sodium hydroxide solution with a concentration of 3-5%, and the dosage of the alkali solution is 30-50 times the weight of the dry insulating wood pulp fiber; the acid solution is a hydrochloric acid solution with a concentration of 1-3%, and the dosage of the acid solution is 40-60 times the weight of the dry insulating wood pulp fiber.

[0016] Further, the coupling agent is a silane coupling agent, the concentration of the coupling agent in the coupling agent solution is 1-3%, and the dosage of the coupling agent solution is 2-3 times the weight of the absolutely dry insulating wood pulp fiber.

[0017] Further, the porous chemical fiber is one or more of polyester (PET) fiber and polyamide (PA) fiber.

[0018] Further, the fineness of the porous chemical fiber is 0.1-0.3 dtex, and the length is 3-5 mm.

[0019] Further, the preparation process of the porous chemical fiber is as follows:

[0020] (1) Weigh a certain amount of porous chemical fiber raw materials and pore-forming agents according to a weight ratio of 3-5:1, dry them respectively and reserve for use;

[0021] (2) Mix the porous chemical fiber raw materials and pore-forming agents, melt and extrude them through a screw extruder, then send them into a box. The melt entering the box is metered by a metering pump and then extruded into a spinning pack, so that the melts of the porous chemical fiber raw materials and pore-forming agents are compounded in a single fiber. After melt spinning and forming, it is ejected from a spinneret, cooled and wound to obtain a composite filament, and then the composite filament is cut to a set length;

[0022] (3) Disperse the cut composite filament in a suitable solvent, dissolve the pore-forming agent, wash, filter and dry to obtain the porous chemical fiber.

[0023] Further, the pore-forming agent is selected from water-soluble polyester or alkali-soluble polyester.

[0024] Further, the preparation method of the high compressive electrolytic capacitor paper includes the steps:

[0025] S1, beating: After making the modified insulating wood pulp fiber and Tencel fiber into slurries respectively, carry out refining treatment. Among them, the beating concentration of the modified insulating wood pulp fiber is 5-10%, and the beating degree is 40-60°SR; the beating concentration of the Tencel fiber is 5-8%, and the beating degree is 70-90°SR;

[0026] S2, pulp blending: Mix the pulp obtained by beating treatment with porous chemical fiber, water-soluble PVA fiber and additives, and then dilute the pulp to a fiber concentration of 0.4-0.6% and reserve for use;

[0027] S3, forming and composite on the wire: After the pulp is on the wire, carry out papermaking, shaping, drying and calendering treatments to obtain the high compressive electrolytic capacitor paper.

[0028] The high-compression electrolytic capacitor paper prepared by the preparation method of the present invention has the advantages of high liquid absorption capacity, high mechanical strength and compressive strength, and is not easily broken down. Detailed implementation manners

[0029] Next, the technical solutions in the embodiments of the present application will be clearly described in conjunction with the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art belong to the scope protected by the present application.

[0030] It should be noted that in the present application, the terms "including", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such a process, method, article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or device including that element. In addition, it should be pointed out that the methods and devices in the embodiments of the present application are not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in a reverse order according to the functions involved. For example, the described methods may be performed in an order different from that described, and various steps may be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0031] A preparation method of a high-compression electrolytic capacitor paper, calculated by weight, the electrolytic capacitor paper comprises the following raw materials:

[0032]

[0033] Preferably, the auxiliary agent comprises 30-40% of AKD, 20-30% of polyethylene oxide, and the balance is polyacrylamide.

[0034] In the said auxiliary agent, AKD can improve the surface tension and wettability of the paper, increase the mechanical strength of the electrolytic capacitor paper, and make it more resistant to folding and tearing; polyethylene oxide can form a gelling substance between the fibers of the electrolytic capacitor paper, thereby increasing the adhesiveness of the paper and helping to improve the mechanical strength and stability of the paper; polyacrylamide has good water retention, can improve the water absorption and water retention of the electrolytic capacitor paper, and at the same time the addition of polyacrylamide helps to improve the mechanical strength of the electrolytic capacitor paper and make it more tear-resistant and fold-resistant.

[0035] Furthermore, the preparation process of the modified insulating wood pulp fiber is as follows:

[0036] (1) Soaking: Add appropriate amount of water to the insulating wood pulp fibers and soak them at room temperature for 3 - 5 h;

[0037] (2) Alkali treatment: Place the water - soaked insulating wood pulp fibers in an alkali solution and soak them at 60 - 90 °C with stirring for 1 - 3 h;

[0038] (3) Acid treatment: Place the alkali - treated insulating wood pulp fibers in an acid solution and soak them at 60 - 90 °C with stirring for 0.5 - 1 h, then rinse them with tap water until neutral, and then put them into an oven at 100 - 120 °C to dry;

[0039] (4) Post - treatment: First, place the acid - treated insulating wood pulp fibers in a coupling agent solution and mix them at room temperature with stirring for 10 - 20 min, then put them into an oven at 100 - 120 °C to dry; Then dissolve 0.5 - 1% of styrene - butadiene - styrene block copolymer by weight of the insulating wood pulp fibers in an appropriate amount of organic solvent, stir until dissolved, mix it with the insulating wood pulp fibers treated with the coupling agent, mix them at room temperature with stirring for 10 - 20 min, and then put them into an oven at 100 - 120 °C to dry again, thus obtaining the modified insulating wood pulp fibers.

[0040] Preferably, the alkali solution is a sodium hydroxide solution with a concentration of 3 - 5%, and the dosage of the alkali solution is 30 - 50 times the weight of the dry - basis insulating wood pulp fibers.

[0041] Preferably, the acid solution is a hydrochloric acid solution with a concentration of 1 - 3%, and the dosage of the acid solution is 40 - 60 times the weight of the dry - basis insulating wood pulp fibers.

[0042] Preferably, the coupling agent is a silane coupling agent, such as A171, A172, A151, KH550, etc.

[0043] Preferably, the concentration of the coupling agent in the coupling agent solution is 1 - 3%.

[0044] Preferably, the dosage of the coupling agent solution is 2 - 3 times the weight of the dry - basis insulating wood pulp fibers.

[0045] Preferably, the solvent in the coupling agent solution is a mixture of ethanol and water.

[0046] As some embodiments of the present invention, the organic solvent used for the styrene - butadiene - styrene block copolymer is selected from one or more of xylene, chloroform, ethanol, and acetone.

[0047] Preferably, the dosage of the organic solvent used for the styrene - butadiene - styrene block copolymer is 2 - 5 times the weight of the dry - basis insulating wood pulp fibers.

[0048] In the preparation process of the modified insulating wood pulp fibers, the insulating wood pulp fibers are first fully swollen by soaking, which is beneficial to improving the effects of subsequent alkali treatment and acid treatment. Then, lignin, partial hemicellulose, pectin ash, etc. in the fibers are removed through alkali treatment and acid treatment, making the surface of the wood pulp fibers have holes and become relatively rough. In this way, the liquid absorption capacity of the wood pulp fibers and the ability and stability of cross-linking and winding combination with other fibers can be enhanced. Moreover, through alkali treatment and acid treatment, the surface fiber bundles of the fibers can also be opened, the gaps between the fibers can be increased, the beating energy consumption can be reduced, and the water absorption of the fibers can be further improved. In addition, alkali treatment and acid treatment can cause changes in the surface functional groups of the fibers, improve the adhesion of the fibers to other materials, and thus improve the mechanical strength of the paper. At the same time, through alkali treatment and acid treatment, impurities or residues on the fiber surface can be removed, making the fibers purer. And through the post-treatment with the coupling agent and styrene-butadiene-styrene block copolymer, the connection ability between the modified insulating wood pulp fibers and other fibers, especially porous chemical fibers, can be improved.

[0049] Preferably, the porous chemical fiber is one or more of polyester (PET) fiber and polyamide (PA) fiber.

[0050] More preferably, the fineness of the porous chemical fiber is 0.1 - 0.3 dtex, and the length is 3 - 5 mm.

[0051] Furthermore, the preparation process of the porous chemical fiber is as follows:

[0052] (1) Weigh a certain amount of porous chemical fiber raw material masterbatch and pore-forming agent masterbatch according to a weight ratio of 3 - 5:1 respectively, dry them respectively and reserve for use;

[0053] (2) Mix the porous chemical fiber raw material and the pore-forming agent, melt and extrude them through a screw extruder, then send them into a box. The melt entering the box is metered by a metering pump and then extruded into a spinning assembly, so that the melts of the porous chemical fiber raw material and the pore-forming agent are compounded in a single fiber. After melt spinning and forming, it is ejected from a spinneret, wound after cooling to obtain a composite filament, and then the composite filament is cut to a set length, that is, 3 - 5 mm;

[0054] (3) Disperse the cut composite filament in a suitable solvent, dissolve the pore-forming agent, then wash, filter and dry to obtain the porous chemical fiber.

[0055] Preferably, the pore-forming agent is selected from water-soluble polyester or alkali-soluble polyester; the porous chemical fiber raw material is polyester (PET) or polyamide (PA).

[0056] In some embodiments of the present invention, the water-soluble polyester is water-soluble polyvinyl alcohol. When the water-soluble polyester is used as the pore-forming agent, the sheared composite filaments can be dispersed in water. After stirring until the pore-forming agent is dissolved, filtration and drying are carried out to obtain the porous chemical fiber.

[0057] In some embodiments of the present invention, the alkali-soluble polyester is polyethylene terephthalate (COPET). When the alkali-soluble polyester is used as the pore-forming agent, the sheared composite filaments can be dispersed in an alkaline solution, such as a sodium hydroxide solution with a concentration of 1-3, and after stirring until the pore-forming agent is dissolved, washing, filtration and drying are carried out to obtain the porous chemical fiber.

[0058] Preferably, the temperatures of the 4 temperature control zones in the screw extruder and the temperature of the box body are respectively: 240-250 °C, 260-270 °C, 270-275 °C, 270-280 °C, and 260-270 °C.

[0059] The porous chemical fiber of the present invention has a small fineness, high strength compared with natural fibers, and contains a porous structure, and has good adsorption capacity for electrolytes. It can effectively improve the mechanical strength, electrical strength and liquid absorption capacity of the high-compression electrolytic capacitor paper used in the present invention.

[0060] Furthermore, the preparation method of the high-compression electrolytic capacitor paper includes the steps:

[0061] S1, beating: After the modified insulating wood pulp fiber and the tencel fiber are respectively made into slurries, beating treatment is carried out. Among them, the beating concentration of the modified insulating wood pulp fiber is 5-10%, and the beating degree is 40-60 °SR; the beating concentration of the tencel fiber is 5-8%, and the beating degree is 70-90 °SR;

[0062] S2, pulp blending: The pulp obtained by the beating treatment is mixed with the porous chemical fiber, the water-soluble PVA fiber and the additives, and then the pulp is diluted to a fiber concentration of 0.4-0.6% and then reserved;

[0063] S3, forming and composite on the wire: After the pulp is formed on the wire, papermaking, shaping, drying and calendering treatments are carried out to obtain the high-compression electrolytic capacitor paper.

[0064] In the preparation process of the electrolytic capacitor paper of the present invention, an ultra-fine porous chemical fiber is used as the skeleton, and the modified insulating wood pulp fiber and the tencel fiber are used as fillers. The modified insulating wood pulp fiber and the tencel fiber are filled between the ultra-fine porous chemical fibers. At the same time, the water-soluble PVA fiber and the additives promote the cross-linking and adhesion between various fibers, forming a paper with high purity, low contents of acid radical ions and conductive metal ions, etc., and the paper quality is uniform, the thickness and the tightness are uniform, and the mechanical and electrical strengths are high, and the adsorption capacity for electrolytes is strong.

[0065] The preparation method of the high compressive electrolytic capacitor paper of the present invention is illustrated by the following specific examples:

[0066] Example 1

[0067] Preparation of modified insulating wood pulp fibers:

[0068] (1) Soaking: Add insulating wood pulp fibers into an appropriate amount of water, soak at room temperature for 4 h, and then filter;

[0069] (2) Alkali treatment: Place the water-soaked insulating wood pulp fibers in a 3% sodium hydroxide solution, soak at 70 °C with stirring for 2 h, and then filter; wherein, the amount of the sodium hydroxide solution is 30 times the weight of the absolutely dry insulating wood pulp fibers;

[0070] (3) Acid treatment: Place the alkali-treated insulating wood pulp fibers in a 2% hydrochloric acid solution, soak at 70 °C with stirring for 0.5 h, filter, then rinse with tap water until neutral, and then put them into an oven at 100 °C for drying; wherein, the amount of the hydrochloric acid solution is 40 times the weight of the absolutely dry insulating wood pulp fibers;

[0071] (4) Post-treatment: First, place the acid-treated insulating wood pulp fibers in a 1% A171 coupling agent solution, the amount of the coupling agent solution is 2 times the weight of the absolutely dry insulating wood pulp fibers, mix at room temperature with stirring for 15 min, and then put them into an oven at 100 °C for drying; then dissolve 1% of the styrene-butadiene-styrene block copolymer by weight of the insulating wood pulp fibers in an appropriate amount of organic solvent, stir until dissolved, mix with the insulating wood pulp fibers treated with the coupling agent, mix at room temperature with stirring for 10 min, and then put them into an oven at 100 °C for drying again to obtain modified insulating wood pulp fibers.

[0072] Example 2

[0073] Preparation of porous chemical fibers:

[0074] (1) Weigh a certain amount of porous chemical fiber raw material polyamide masterbatch and pore-forming agent water-soluble polyvinyl alcohol masterbatch according to a weight ratio of 5:1 respectively, dry them separately for later use;

[0075] (2) Mix the porous chemical fiber raw material and the pore-forming agent, melt and extrude them through a screw extruder, then send them into a box body. The molten material entering the box body is quantitatively metered by a metering pump and then extruded into a spinning assembly, so that the melts of the porous chemical fiber raw material and the pore-forming agent are compounded in a single fiber. After melt spinning and forming, it is ejected from a spinneret, cooled and then wound to obtain a composite filament, and then the composite filament is cut into 3 - 5 mm; wherein, the temperatures of the 4 temperature control zones in the screw extruder and the box body are: 242 °C, 265 °C, 273 °C, 276 °C, and 264 °C respectively.

[0076] (3) Disperse the cut composite filaments in an appropriate amount of water and stir until the pore-forming agent, water-soluble polyvinyl alcohol, is dissolved. Then, wash, filter, and dry to obtain the porous chemical fiber.

[0077] Example 3

[0078] Preparation of electrolytic capacitor paper:

[0079] The electrolytic capacitor paper comprises the following raw materials in parts by weight: 50 parts of the modified insulating wood pulp fiber prepared in Example 1 above, 30 parts of the porous chemical fiber prepared in Example 2 above, 20 parts of tencel fiber, 5 parts of water-soluble PVA fiber, and 3 parts of an auxiliary agent. Among them, the auxiliary agent includes 40% of AKD, 30% of polyethylene oxide, and 30% of polyacrylamide;

[0080] Preparation process of the electrolytic capacitor paper:

[0081] S1, beating: After separately making the modified insulating wood pulp fiber and tencel fiber into slurries, carry out refining treatment. Among them, the beating consistency of the modified insulating wood pulp fiber is 5%, and the beating degree is 41°SR; the beating consistency of the tencel fiber is 5%, and the beating degree is 70°SR;

[0082] S2, pulp blending: Mix the slurries obtained from the beating treatment with the porous chemical fiber, water-soluble PVA fiber, and auxiliary agent. Then, dilute the pulp to a fiber concentration of 0.4% and set aside;

[0083] S3, forming and composite on the wire: After the pulp is on the wire, carry out papermaking, shaping, drying, and calendering treatments to obtain a high compressive strength electrolytic capacitor paper.

[0084] Example 4

[0085] Preparation of electrolytic capacitor paper:

[0086] The electrolytic capacitor paper comprises the following raw materials in parts by weight: 54 parts of the modified insulating wood pulp fiber prepared in Example 1 above, 35 parts of the porous chemical fiber prepared in Example 2 above, 23 parts of tencel fiber, 6 parts of water-soluble PVA fiber, and 5 parts of an auxiliary agent. Among them, the auxiliary agent includes 30% of AKD, 20% of polyethylene oxide, and 50% of polyacrylamide;

[0087] Preparation process of the electrolytic capacitor paper:

[0088] S1, beating: After separately making the modified insulating wood pulp fiber and tencel fiber into slurries, carry out refining treatment. Among them, the beating consistency of the modified insulating wood pulp fiber is 8%, and the beating degree is 48°SR; the beating consistency of the tencel fiber is 6%, and the beating degree is 76°SR;

[0089] S2, Pulp blending: Mix the pulp obtained from beating with porous chemical fibers, water-soluble PVA fibers and additives. After that, dilute the pulp to a fiber concentration of 0.5% and set aside.

[0090] S3, Web forming and lamination: After the pulp is on the wire, perform papermaking, shaping, drying and calendering to obtain high compressive strength electrolytic capacitor paper.

[0091] Example 5

[0092] Preparation of electrolytic capacitor paper:

[0093] The electrolytic capacitor paper comprises the following raw materials in parts by weight: 60 parts of the modified insulating wood pulp fibers prepared in Example 1 above, 40 parts of the porous chemical fibers prepared in Example 2 above, 30 parts of tencel fibers, 10 parts of water-soluble PVA fibers, and 8 parts of additives. Among them, the additives include 35% AKD, 25% polyethylene oxide and 40% polyacrylamide.

[0094] Preparation process of electrolytic capacitor paper:

[0095] S1, Beating: After separately making the modified insulating wood pulp fibers and tencel fibers into pulp, perform refining treatment. Among them, the beating concentration of the modified insulating wood pulp fibers is 10%, and the beating degree is 60°SR; the beating concentration of the tencel fibers is 8%, and the beating degree is 90°SR.

[0096] S2, Pulp blending: Mix the pulp obtained from beating with porous chemical fibers, water-soluble PVA fibers and additives. After that, dilute the pulp to a fiber concentration of 0.6% and set aside.

[0097] S3, Web forming and lamination: After the pulp is on the wire, perform papermaking, shaping, drying and calendering to obtain high compressive strength electrolytic capacitor paper.

[0098] Comparative Example 1

[0099] Preparation of electrolytic capacitor paper:

[0100] The only difference between Comparative Example 1 and Example 5 above is that: unmodified insulating wood pulp fibers are used instead of modified insulating wood pulp fibers to prepare electrolytic capacitor paper.

[0101] Comparative Example 2

[0102] Preparation of electrolytic capacitor paper:

[0103] The only difference between Comparative Example 2 and Example 5 above is that: the insulating wood pulp fibers that have been soaked, alkali-treated and acid-treated and not post-treated in Example 1 above are used instead of modified insulating wood pulp fibers to prepare electrolytic capacitor paper.

[0104] Comparative Example 3

[0105] Preparation of electrolytic capacitor paper:

[0106] The difference between Comparative Example 3 and Example 5 above is only that: polyamide fibers without a porous structure are used instead of porous chemical fibers to prepare electrolytic capacitor paper.

[0107] Comparative Example 4

[0108] Preparation of electrolytic capacitor paper:

[0109] The difference between Comparative Example 4 and Example 5 above is only that: no additives are added when preparing electrolytic capacitor paper.

[0110] Test Example 1

[0111] The electrolytic capacitor papers prepared in Examples 3 to 5 above and Comparative Examples 1 to 4 were tested. Among them, the specimens were prepared according to the provisions of GB / T450; the density and thickness were measured according to the provisions of GB / T451.3, the tensile strength was measured according to GB / T12914, the liquid absorption height was measured using GB / T461.1-2002, and the breakdown voltage was measured using GB / T3333-1999. The test results are shown in Table 1 below:

[0112] Table 1 Performance test results of electrolytic capacitor paper

[0113]

[0114]

[0115] The embodiments of the present application have been described above. Without conflict, the embodiments and the features in the embodiments in the present application can be combined with each other. The present application is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Those of ordinary skill in the art, under the inspiration of the present application and without departing from the purpose of the present application and the scope protected by the claims, can also make many forms, all of which fall within the protection scope of the present application.

Claims

1. A preparation method of high compressive electrolytic capacitor paper, characterized in that, The electrolytic capacitor paper comprises the following raw materials by weight parts: 50 - 60 parts of modified insulating wood pulp fiber; 30 - 40 parts of porous chemical fiber; 20 - 30 parts of tencel fiber; 5 - 10 parts of water-soluble PVA fiber; 3 - 8 parts of auxiliary agent; The auxiliary agent comprises 30 - 40% of AKD, 20 - 30% of polyethylene oxide, and the balance is polyacrylamide; The preparation process of the modified insulating wood pulp fiber is as follows: (1) Soaking: Add the insulating wood pulp fiber into appropriate water and soak at room temperature for 3 - 5 h; (2) Alkali treatment: Place the water-soaked insulating wood pulp fiber in an alkali solution and soak at 60 - 90 °C with stirring for 1 - 3 h; (3) Acid treatment: Place the alkali-treated insulating wood pulp fiber in an acid solution and soak at 60 - 90 °C with stirring for 0.5 - 1 h, then rinse with tap water until neutral, and then put it into an oven at 100 - 120 °C for drying; (4) Post-treatment: First, place the acid-treated insulating wood pulp fiber in a coupling agent solution and mix at room temperature with stirring for 10 - 20 min, then put it into an oven at 100 - 120 °C for drying; then dissolve 0.5 - 1% of styrene-butadiene-styrene block copolymer by weight of the insulating wood pulp fiber in appropriate organic solvent, stir until dissolved, mix with the insulating wood pulp fiber treated with the coupling agent, mix at room temperature with stirring for 10 - 20 min, and then put it into an oven at 100 - 120 °C for drying again to obtain the modified insulating wood pulp fiber.

2. The preparation method of the electrolytic capacitor paper according to claim 1, characterized in that, The alkali solution is a sodium hydroxide solution with a concentration of 3 - 5%, and the amount of the alkali solution is 30 - 50 times the weight of the absolute dry insulating wood pulp fiber; the acid solution is a hydrochloric acid solution with a concentration of 1 - 3%, and the amount of the acid solution is 40 - 60 times the weight of the absolute dry insulating wood pulp fiber.

3. The preparation method of the electrolytic capacitor paper according to claim 1, characterized in that, The coupling agent is a silane coupling agent, the concentration of the coupling agent in the coupling agent solution is 1 - 3%, and the amount of the coupling agent solution is 2 - 3 times the weight of the absolute dry insulating wood pulp fiber.

4. The preparation method of the electrolytic capacitor paper according to claim 1, characterized in that, The porous chemical fiber is one or more of polyester fiber and polyamide fiber.

5. The preparation method of the electrolytic capacitor paper according to claim 1 or 4, characterized in that, The fineness of the porous chemical fiber is 0.1 - 0.3 dtex, and the length is 3 - 5 mm.

6. The method for preparing electrolytic capacitor paper according to claim 1 or 4, characterized in that, The preparation process of the porous chemical fiber is as follows: (1) Weigh a certain amount of porous chemical fiber raw material and pore-forming agent respectively according to the weight ratio of 3 - 5:1, dry them respectively and reserve; (2) Mix the porous chemical fiber raw material and the pore-forming agent, melt and extrude them through a screw extruder, then send them into a box, and the melt entering the box is quantitatively metered by a metering pump and extruded into a spinning pack, so that the melts of the porous chemical fiber raw material and the pore-forming agent are compounded in a single fiber, and after melt spinning and forming, it is ejected from a spinneret, cooled and wound to obtain a composite filament, and then cut the composite filament to a set length; (3) Disperse the cut composite filament in an appropriate solvent, dissolve the pore-forming agent, then wash, filter and dry to obtain the porous chemical fiber.

7. The method for preparing electrolytic capacitor paper according to claim 6, characterized in that, The pore-forming agent is selected from water-soluble polyester or alkali-soluble polyester.

8. The preparation method of the electrolytic capacitor paper according to claim 1, characterized in that, The preparation method of the high compressive electrolytic capacitor paper includes the steps: S1, Pulping: After separately making the modified insulating wood pulp fibers and Tencel fibers into slurries, perform beating treatment. Among them, the beating consistency of the modified insulating wood pulp fibers is 5 - 10%, and the beating degree is 40 - 60°SR; the beating consistency of the Tencel fibers is 5 - 8%, and the beating degree is 70 - 90°SR; S2, Blending: Mix the slurries obtained from the beating treatment with porous chemical fibers, water-soluble PVA fibers, and additives. Then dilute the slurry to a fiber concentration of 0.4 - 0.6% and set aside; S3, Sheet forming and lamination: After the slurry is on the wire, perform papermaking, shaping, drying, and calendering treatments to obtain high compressive electrolytic capacitor paper.

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