A production method of capacitor aluminum-plastic film and aluminum electrolytic capacitor formation foil

Abstract

The application provides a production method of an aluminum-plastic film and an aluminum electrolytic capacitor formation foil, relates to the field of formation foil production, and is characterized by an aluminum-plastic film structure and a preparation process of the formation foil. The aluminum-plastic film comprises, from inside to outside, an aluminum electrolytic capacitor formation foil, a bonding layer and a heat-sealing layer. The bonding layer is composed of maleic anhydride modified polyolefin, diisocyanate and glycidyl ether type epoxy resin, and the heat-sealing layer is composed of polypropylene and polyphenylene sulfide. The production of the formation foil is realized through multi-stage electrolytic oxidation and optimized combination of various additives, so that the thickness and compactness of the oxidation film are gradually improved, the voltage resistance, specific capacity and mechanical strength of the formation foil are significantly improved, and the leakage current is reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of chemical conversion foil production, and particularly relates to a production method of a capacitor aluminum-plastic film and an aluminum electrolytic capacitor chemical conversion foil. BACKGROUND

[0002] Aluminum electrolytic capacitors have been widely used in the fields of power electronics, communication equipment, household appliances, etc. due to their high capacity and high voltage resistance characteristics. The chemical conversion foil, as a core component of the aluminum electrolytic capacitor, directly affects the performance and service life of the capacitor. The traditional chemical conversion foil production method usually adopts a single electrolytic oxidation process, which can form a certain oxide film, but has deficiencies in film thickness, compactness and uniformity, resulting in limited voltage resistance and capacitance performance of the capacitor. In addition, the traditional method has high requirements for environmental control during production and low production efficiency, which is difficult to meet the demand for high-performance capacitors in modern industry.

[0003] In recent years, with the rapid development of electronic technology, the performance requirements of aluminum electrolytic capacitors are becoming higher and higher, especially under harsh conditions such as high frequency, high temperature and high humidity, the stability and reliability of capacitors face greater challenges. The existing chemical conversion foil production technology still has a lot of room for improvement in improving the dielectric strength of the oxide film, reducing the leakage current and improving the mechanical strength, etc. For example, although the performance of the oxide film can be improved by adding some additives, the type and amount of these additives have a great influence on the final performance of the film, which needs to be further optimized. In addition, the energy consumption and environmental pollution problems in the production process are increasingly concerned, how to reduce the production cost and environmental impact while ensuring product quality is an important issue faced by the current chemical conversion foil production technology. SUMMARY

[0004] In view of the above problems, the application provides a production method of a capacitor aluminum-plastic film and an aluminum electrolytic capacitor chemical conversion foil.

[0005] To achieve the above purpose, the application is implemented by the following technical scheme: a production method of a capacitor aluminum-plastic film and an aluminum electrolytic capacitor chemical conversion foil, comprising the following steps:

[0006] Hydration treatment: after the etched aluminum foil is unwound, boiling water hydration treatment is carried out, 95±2℃ ultra-pure water is used, and the treatment time is 10-12min to form a pre-oxidation layer;

[0007] First stage electrolytic oxidation: the corrosion aluminum foil after hydration treatment is placed in a solution of 4.0wt% boric acid, 3.0wt% phosphoric acid, and 0.5wt% ammonium adipate, 0.01wt%-0.03wt% nano titanium dioxide is added, 0.05wt%-0.1wt% nano aluminum oxide is added, 0.1wt% polyethylene glycol is added, ammonia water is used to adjust the pH to 5.5-6.0, the voltage is 200-300V, the pulse mode is used, the duty cycle is 30%, the temperature is 45±2℃, and electrolysis is performed for 15-20min;

[0008] Second stage electrolytic oxidation: the aluminum foil after the first stage electrolytic oxidation is placed in a solution of 6.0wt% boric acid, 5.0wt% phosphoric acid, and 0.3wt% ammonium adipate, ammonia water is used to adjust the pH to 6.0-6.5, the voltage is 250-350V, the temperature is 50±2℃, and electrolysis is performed for 15-20min;

[0009] Middle treatment I: the aluminum foil after the second stage electrolytic oxidation is subjected to middle treatment, is washed with deionized water, and then is soaked in a solution of 0.1wt%-0.5wt% citric acid and 0.02wt%-0.06wt% sodium gluconate, the temperature is controlled to be 35℃-40℃, and the time is 5-10min;

[0010] Third stage electrolytic oxidation: the aluminum foil after the first stage electrolytic oxidation is placed in a solution of 8.0wt% boric acid, 7.0wt% phosphoric acid, and 0.2wt% ammonium adipate, 0.02wt%-0.06wt% nano zinc oxide particles are added, ammonia water is used to adjust the pH to 6.5-7.0, the voltage is 300-400V, direct current is superimposed with high-frequency pulse, the temperature is 55±2℃, and electrolysis is performed for 20-25min;

[0011] Power feeding tank treatment: the aluminum foil after the third stage electrolytic oxidation is placed in a power feeding tank, 1.0wt%-2.0wt% ammonium adipate, 0.02wt%-0.05wt% polyvinylpyrrolidone, and 0.1wt%-0.3wt% PEG-200 solution are added to the power feeding tank, the temperature is controlled to be 40℃-45℃, and the treatment time is 10-17min;

[0012] Roasting I: the aluminum foil after the power feeding tank treatment is sent into a roasting furnace, nitrogen protection is performed, the temperature is controlled to be 200-250℃, and the roasting time is 25-30min;

[0013] Middle treatment II: deionized water is used to wash, and then the aluminum foil is soaked in a solution containing 0.2wt%-0.5wt% acetic acid and 0.01wt%-0.03wt% chitosan, the temperature is controlled to be 30℃-35℃, and the time is 5-9min;

[0014] Fourth stage electrolytic oxidation I: the aluminum foil after the second stage treatment is placed in a solution of 10.0wt% boric acid, 9.0wt% phosphoric acid and 0.1wt% ammonium adipate, the pH is adjusted to 6.5-7.0 using ammonia water, the voltage is 350-450V, the temperature is 60±2℃, and the electrolysis time is 25-30min;

[0015] Fourth stage electrolytic oxidation II: the process parameters and formula of the fourth stage electrolytic oxidation I are repeated, and the electrolytic oxidation treatment is performed again;

[0016] Baking II: the aluminum foil after the fourth stage electrolytic oxidation II is sent into a baking furnace, the temperature is controlled at 250-300℃ under nitrogen protection, and the baking time is 15-35min;

[0017] Fourth stage electrolytic oxidation III: the process parameters and formula of the fourth stage electrolytic oxidation I are repeated, and the electrolytic oxidation treatment is performed again;

[0018] Fourth stage electrolytic oxidation IV: the aluminum foil after the fourth stage electrolytic oxidation III is placed in a solution of 10.0wt% boric acid, 9.0wt% phosphoric acid and 0.1wt% ammonium adipate, the pH is adjusted to 6.5-7.0 using ammonia water, the voltage is 400-500V, the pulse mode is used with a duty cycle of 50%, the temperature is 60±2℃, and the electrolysis time is 25-30min;

[0019] Baking III: the aluminum foil after the fourth stage electrolytic oxidation IV is sent into a baking furnace, the temperature is controlled at 300-350℃ under nitrogen protection, and the baking time is 20-40min;

[0020] Post-treatment: the aluminum foil is immersed in a solution of 0.1wt%-0.3wt% silane coupling agent, infrared radiation is performed for 30-50min at a wavelength of 3-5μm, and the final formed aluminum electrolytic capacitor formation foil is obtained after vacuum drying.

[0021] Preparation of capacitor aluminum-plastic film: maleic anhydride modified polyolefin, diisocyanate and glycidyl ether type epoxy resin are mixed at a mass ratio of 5:2:1, melted and stirred at 80-120℃ to prepare an adhesive layer slurry, which is uniformly coated on the surface of the aluminum electrolytic capacitor formation foil by a doctor blade coating process, and the thickness is controlled at 20-30μm, and an adhesive layer is formed after curing; then polypropylene and polyphenylene sulfide are melt blended at a mass ratio of 7:3, and a heat sealing layer film is prepared by a twin-screw extruder at 200-240℃, and the thickness is controlled at 50-80μm, and finally the heat sealing layer is compounded on the surface of the adhesive layer by a hot pressing lamination process, and the hot pressing temperature is 160-180℃, the pressure is 8-12MPa, and the capacitor aluminum-plastic film is obtained after cooling and setting.

[0022] Preferably, the conductivity of the ultrapure water is ≤0.1μS / cm, the particle size of the nanometer titanium dioxide is 10-50nm, and the particle size of the nanometer aluminum oxide in the nanometer aluminum oxide dispersion liquid is 20-80nm.

[0023] Preferably, all electrolytic cells in the electrolytic oxidation step adopt titanium-based coated electrodes, the electrode spacing is 10-30mm; the electrolyte circulation flow rate is 0.5-2.0m / s, and the liquid level difference is controlled to be ±2mm.

[0024] Preferably, the frequency of the pulse mode in the first-stage electrolytic oxidation and the fourth-stage electrolytic oxidation is 100-500Hz, and the waveform is square wave or trapezoidal wave.

[0025] Preferably, the concentration of the sodium gluconate used in the intermediate treatment I is 0.01-0.05wt%, the solution pH value is 3.5-4.5, and the soaking process in the intermediate treatment I is carried out under inert gas protection.

[0026] Preferably, the frequency of the high-frequency pulse in the third-stage electrolytic oxidation is 2-5kHz, and the duty cycle is 20%-40%.

[0027] Preferably, the particle size of the nano-zinc oxide particles is 30-100nm.

[0028] In the feeding tank treatment, the molecular weight of the polyvinylpyrrolidone is 10000-50000.

[0029] Preferably, the solution is kept uniform by magnetic stirring, and the stirring rate is 100-300rpm.

[0030] Preferably, the gas flow rate of the nitrogen protection in the calcination I, the calcination II and the calcination III is 5-15L / min; the heating rate is 5-10℃ / min, and the cooling rate is 8-15℃ / min.

[0031] Preferably, the deacetylation degree of the chitosan is ≥90%, and the molecular weight is 50000-200000.

[0032] Preferably, the silane coupling agent is at least one of KH-550, KH-560 or KH-570.

[0033] The application provides a capacitor aluminum-plastic film and a production method of aluminum electrolytic capacitor formation foil.

[0034] 1. The thickness and compactness of the oxide film are gradually improved through multi-stage electrolytic oxidation treatment, and the voltage resistance performance of the formation foil is significantly improved. The voltage resistance of Examples 1-5 is all above 530VF, and the highest can reach 551VF.

[0035] 2. The formation foil produced by the method has high specific capacity, and the specific capacity of Examples 1-5 is all above 0.95μF / cm², and the highest can reach 0.986μF / cm².

[0036] 3、The formed foil produced by the method has a low leakage current, the leakage currents of Examples 1-5 are all below 56 μA / cm2, and the lowest can reach 51 μA / cm2, which is mainly due to the addition of nanometer alumina and nanometer zinc oxide and other nanometer materials in the electrolytic oxidation process, which can fill the micropores of the oxide film, improve the surface flatness of the oxide film, and improve the breakdown voltage, thereby reducing the leakage current. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only 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 a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0038] Example 1:

[0039] A production method of a capacitor aluminum-plastic film and an aluminum electrolytic capacitor formed foil, comprising the following steps:

[0040] Hydration treatment: after the etched aluminum foil is unwound, boiling water hydration treatment is performed, 95±2 ℃ ultrapure water is used, and the treatment time is 10 minutes.

[0041] First-stage electrolytic oxidation: the etched aluminum foil after hydration treatment is placed in a 4.0wt% boric acid, 3.0wt% phosphoric acid, and 0.5wt% ammonium adipate solution, 0.01wt% nanometer titanium dioxide, 0.05wt% nanometer alumina, and 0.1wt% polyethylene glycol are added, ammonia water is used to adjust the pH to 5.5-6.0, the voltage is 200-300V, the pulse mode frequency is 100-500Hz, the waveform is a square wave, the duty cycle is 30%, the temperature is 45±2 ℃, the electrolysis time is 15 minutes, a titanium-based coated electrode is used for the electrolytic cell, and the electrode spacing is 10mm; the electrolyte circulating flow rate is 0.5m / s, and the liquid level difference is controlled to be ±2mm.

[0042] Second-stage electrolytic oxidation: the aluminum foil after the first-stage electrolytic oxidation is placed in a 6.0wt% boric acid, 5.0wt% phosphoric acid, and 0.3wt% ammonium adipate solution. Ammonia water is used to adjust the pH to 6.0-6.5, the voltage is 250-350V, the temperature is 50±2 ℃, the direct current mode is used, and the electrolysis time is 15 minutes.

[0043] Middle treatment I: the aluminum foil after the second-stage electrolytic oxidation is washed with deionized water, and then soaked in a 0.1wt% citric acid and 0.01wt% sodium gluconate solution, the temperature is controlled at 35 ℃, and the time is 5 minutes.

[0044] The soaking process is carried out under inert gas protection.

[0045] Third stage electrolytic oxidation: The aluminum foil from the first stage electrolytic oxidation was placed in a solution of 8.0wt% boric acid, 7.0wt% phosphoric acid, and 0.2wt% ammonium adipate, with 0.05wt% nano-zinc oxide particles added, and the pH was adjusted to 6.5-7.0 using ammonia water, with a voltage of 300-400V, direct current superimposed with high-frequency pulses at a frequency of 2-5kHz and a duty cycle of 20%, a temperature of 55±2°C, and an electrolysis time of 20 minutes.

[0046] Feed tank treatment: The aluminum foil after the third stage electrolytic oxidation was placed in a feed tank, with 1.0wt% ammonium adipate, 0.02wt% polyvinylpyrrolidone, and 0.1wt% PEG-2000 solution added to the feed tank, with the temperature controlled at 40°C, the treatment time being 10 minutes, and the solution kept uniform by magnetic stirring at a stirring rate of 100rpm.

[0047] Roasting I: The aluminum foil after the feed tank treatment was sent to a roasting furnace under nitrogen protection, with the temperature controlled at 200°C, the roasting time being 10 minutes, the nitrogen flow rate being 5L / min, the heating rate being 5°C / min, and the cooling rate being 8°C / min.

[0048] Middle treatment II: The aluminum foil was rinsed with deionized water and then soaked in a solution containing 0.2wt% acetic acid with 0.01wt% chitosan added, with the temperature controlled at 30°C and the time being 5 minutes.

[0049] Fourth stage electrolytic oxidation I: The aluminum foil after the middle treatment II was placed in a solution of 10.0wt% boric acid, 9.0wt% phosphoric acid, and 0.1wt% ammonium adipate, with the pH adjusted to 6.5-7.0 using ammonia water, a voltage of 350-450V, a temperature of 60±2°C, and an electrolysis time of 25 minutes.

[0050] Fourth stage electrolytic oxidation II: The process parameters and formula of the fourth stage electrolytic oxidation I were repeated for the electrolytic oxidation treatment again.

[0051] Roasting II: The aluminum foil after the fourth stage electrolytic oxidation II was sent to a roasting furnace under nitrogen protection, with the temperature controlled at 250°C, the roasting time being 15 minutes, the nitrogen flow rate being 10L / min, the heating rate being 8°C / min, and the cooling rate being 12°C / min.

[0052] Fourth stage electrolytic oxidation III: The aluminum foil after the fourth stage electrolytic oxidation II was placed in a solution of 10.0wt% boric acid, 9.0wt% phosphoric acid, and 0.1wt% ammonium adipate, with the pH adjusted to 6.5-7.0 using ammonia water, a voltage of 400-500V, a pulse mode with a duty cycle of 50%, a temperature of 60±2°C, and an electrolysis time of 25 minutes.

[0053] Fourth stage electrolytic oxidation IV: repeat the process parameters and formula of the fourth stage electrolytic oxidation III, and electrolytic oxidation treatment is carried out again.

[0054] Baking III: the aluminum foil after the fourth stage electrolytic oxidation IV is sent into a baking furnace, nitrogen protection, temperature control is 300-350℃, baking time is 20 minutes, nitrogen flow rate is 15L / min, heating rate is 10℃ / min, cooling rate is 15℃ / min.

[0055] Post-treatment: dipping 0.1wt% silane coupling agent solution, infrared radiation for 30 minutes, vacuum drying to obtain the final aluminum electrolytic capacitor formation foil.

[0056] Preparation of capacitor aluminum plastic film: maleic anhydride modified polyolefin, diisocyanate and glycidyl ether type epoxy resin are mixed in a mass ratio of 5:2:1 to prepare an adhesive layer slurry by melting and stirring at 115℃, which is uniformly coated on the surface of the aluminum electrolytic capacitor formation foil by a doctor blade coating process, and the thickness is controlled at 30μm, and an adhesive layer is formed after curing; then polypropylene and polyphenylene sulfide are melt blended in a mass ratio of 7:3, and a heat sealing layer film is prepared by a twin-screw extruder at 200-240℃, and the thickness is controlled at 80μm, and finally the heat sealing layer is compounded on the surface of the adhesive layer by a hot pressing lamination process, and the hot pressing temperature is 170℃, the pressure is 11 MPa, and the capacitor aluminum plastic film is obtained after cooling and setting.

[0057] Example 2:

[0058] A production method of a capacitor aluminum plastic film and an aluminum electrolytic capacitor formation foil, comprising the following steps:

[0059] Hydration treatment: after the etched aluminum foil is unwound, boiling water hydration treatment is carried out, and 95±2℃ ultrapure water is used, and the treatment time is 12 minutes.

[0060] First stage electrolytic oxidation: the etched aluminum foil after hydration treatment is placed in a solution of 4.5wt% boric acid, 3.5wt% phosphoric acid, 0.6wt% ammonium adipate, 0.02wt% nano titanium dioxide, 0.07wt% nano aluminum oxide and 0.15wt% polyethylene glycol. Ammonia is used to adjust the pH to 5.8-6.2, the voltage is 220-320V, the pulse mode, the frequency is 200-500Hz, the waveform is square wave, the duty cycle is 35%, the temperature is 47±2℃, the electrolysis time is 18 minutes, the electrolytic cell uses titanium-based coated electrode, and the electrode spacing is 12mm; the electrolyte circulating flow rate is 1.0m / s, and the liquid level difference is controlled to be ±2mm.

[0061] Second stage electrolytic oxidation: The first stage electrolytic oxidized aluminum foil was placed in a solution of 6.5wt% boric acid, 5.5wt% phosphoric acid, and 0.4wt% ammonium adipate, and the pH was adjusted to 6.2-6.8 using ammonia water. The voltage was 280-380V, the temperature was 52±2°C, and the electrolysis time was 18 minutes.

[0062] Intermediate treatment I: The second stage electrolytic oxidized aluminum foil was rinsed with deionized water and then soaked in a solution of 0.15wt% citric acid and 0.02wt% sodium gluconate. The temperature was controlled at 38°C, and the soaking time was 6 minutes. The soaking process was carried out under inert gas protection.

[0063] Third stage electrolytic oxidation: The first stage electrolytic oxidized aluminum foil was placed in a solution of 8.5wt% boric acid, 7.5wt% phosphoric acid, and 0.3wt% ammonium adipate, and 0.1wt% nano-zinc oxide particles were added. The pH was adjusted to 6.8-7.2 using ammonia water. The voltage was 350-450V, the temperature was 58±2°C, and the electrolysis time was 25 minutes.

[0064] Feeding tank treatment: The third stage electrolytic oxidized aluminum foil was placed in a feeding tank, and a solution of 1.2wt% ammonium adipate, 0.03wt% polyvinylpyrrolidone, and 0.15wt% PEG-2000 was added to the feeding tank. The temperature was controlled at 42°C, and the treatment time was 12 minutes. The solution was kept uniform by magnetic stirring at a stirring rate of 150rpm.

[0065] Baking I: The feeding tank treated aluminum foil was sent to a baking furnace under nitrogen protection. The temperature was controlled at 220°C, the baking time was 12 minutes, the nitrogen flow rate was 8L / min, the heating rate was 6°C / min, and the cooling rate was 10°C / min.

[0066] Intermediate treatment II: The aluminum foil was rinsed with deionized water and then soaked in a solution containing 0.3wt% acetic acid and 0.02wt% chitosan. The temperature was controlled at 32°C, and the soaking time was 6 minutes.

[0067] Fourth stage electrolytic oxidation I: The intermediate treatment II treated aluminum foil was placed in a solution of 11.0wt% boric acid, 9.5wt% phosphoric acid, and 0.2wt% ammonium adipate. The pH was adjusted to 6.8-7.2 using ammonia water. The voltage was 400-500V, the temperature was 62±2°C, and the electrolysis time was 30 minutes.

[0068] Fourth stage electrolytic oxidation II: The process parameters and formula of the fourth stage electrolytic oxidation I were repeated for the second electrolytic oxidation treatment.

[0069] Roasting II: The aluminum foil after the fourth stage electrolytic oxidation II was sent into the roasting furnace, protected by nitrogen, the temperature was controlled at 280℃, the roasting time was 20 minutes, the nitrogen flow rate was 12 L / min, the heating rate was 9℃ / min, and the cooling rate was 14℃ / min.

[0070] Fourth stage electrolytic oxidation III: The aluminum foil after the fourth stage electrolytic oxidation II was placed in a solution of 11.5wt% boric acid, 10.0wt% phosphoric acid, and 0.25wt% ammonium adipate, the pH was adjusted to 7.0-7.4 using ammonia water, the voltage was 450-550V, the pulse mode was used, the frequency was 200-500Hz, the waveform was trapezoidal wave, the duty cycle was 60%, the temperature was 64±2℃, and the electrolysis time was 32 minutes.

[0071] Fourth stage electrolytic oxidation IV: The process parameters and formula of the fourth stage electrolytic oxidation III were repeated, and the electrolytic oxidation treatment was performed again.

[0072] Roasting III: The aluminum foil after the fourth stage electrolytic oxidation IV was sent into the roasting furnace, protected by nitrogen, the temperature was controlled at 320-360℃, the roasting time was 25 minutes, the nitrogen flow rate was 18 L / min, the heating rate was 12℃ / min, and the cooling rate was 18℃ / min.

[0073] Post-treatment: The aluminum electrolytic capacitor anode foil was obtained after immersion in a 0.2wt% silane coupling agent solution, infrared radiation for 45 minutes, and vacuum drying.

[0074] Preparation of capacitor aluminum-plastic film: Maleic anhydride modified polyolefin, diisocyanate, and glycidyl ether type epoxy resin were mixed in a mass ratio of 5:2:1, melted and stirred at 100℃ to prepare an adhesive layer slurry, which was uniformly coated on the surface of the aluminum electrolytic capacitor anode foil by a doctor blade coating process, with a thickness controlled at 20-30μm, and an adhesive layer was formed after curing; then polypropylene and polyphenylene sulfide were melt blended in a mass ratio of 7:3, and a heat-sealing layer film was prepared by a twin-screw extruder at 200℃, with a thickness controlled at 75μm, and finally the heat-sealing layer was compounded on the surface of the adhesive layer by a hot press lamination process, with a hot press temperature of 165℃ and a pressure of 8 MPa, and an aluminum-plastic film for capacitors was obtained after cooling and setting.

[0075] Example 3:

[0076] A production method of an aluminum-plastic film for capacitors and an aluminum electrolytic capacitor anode foil, comprising the following steps:

[0077] Hydration treatment: The etched aluminum foil was unwound and subjected to boiling water hydration treatment using 95±2℃ ultrapure water for 11 minutes.

[0078] First-stage electrolytic oxidation: The corrosion-treated aluminum foil is placed in a solution of 4.2 wt% boric acid, 3.2 wt% phosphoric acid, and 0.55 wt% ammonium adipate, with 0.015 wt% nano-titanium dioxide, 0.06 wt% nano-aluminum oxide, and 0.12 wt% polyethylene glycol added. The pH is adjusted to 5.6-6.1 using ammonia water, the voltage is 210-310 V, the pulse mode frequency is 150-450 Hz, the waveform is square wave with a duty cycle of 32%, the temperature is 46±2°C, and the electrolysis time is 16 minutes.

[0079] The electrolytic cell uses titanium-based coated electrodes with an electrode spacing of 11 mm. The electrolyte circulation flow rate is 1.2 m / s, and the liquid level difference is controlled to ±2 mm.

[0080] Second-stage electrolytic oxidation: The aluminum foil from the first-stage electrolytic oxidation is placed in a solution of 6.2 wt% boric acid, 5.2 wt% phosphoric acid, and 0.35 wt% ammonium adipate, with the pH adjusted to 6.1-6.6 using ammonia water. The voltage is 260-360 V, the temperature is 51±2°C, and the electrolysis time is 17 minutes.

[0081] Intermediate treatment I: The aluminum foil from the second-stage electrolytic oxidation is rinsed with deionized water and then soaked in a solution of 0.12 wt% citric acid and 0.03 wt% sodium gluconate at a temperature of 37°C for 7 minutes. The soaking process is carried out under inert gas protection.

[0082] Third-stage electrolytic oxidation: The aluminum foil from the first-stage electrolytic oxidation is placed in a solution of 8.2 wt% boric acid, 7.2 wt% phosphoric acid, and 0.22 wt% ammonium adipate, with 0.04 wt% nano-zinc oxide particles added. The pH is adjusted to 6.7-7.1 using ammonia water, the voltage is 330-430 V, the direct current is superimposed with high-frequency pulses at a frequency of 4-8 kHz and a duty cycle of 25%, the temperature is 56±2°C, and the electrolysis time is 22 minutes.

[0083] Feed tank treatment: The aluminum foil after the third-stage electrolytic oxidation is placed in a feed tank containing a solution of 1.1 wt% ammonium adipate, 0.04 wt% polyvinylpyrrolidone with a molecular weight of 30,000-70,000, and 0.2 wt% PEG-200, with the temperature controlled at 41°C and the treatment time being 11 minutes. The solution is kept uniform by magnetic stirring at a rate of 180 rpm.

[0084] Calcination I: The aluminum foil after the feed tank treatment is sent to a calcination furnace under nitrogen protection, with the temperature controlled at 215°C, the calcination time being 11 minutes, the nitrogen flow rate being 7 L / min, the heating rate being 7°C / min, and the cooling rate being 9°C / min.

[0085] Middle treatment II; rinsing with deionized water, then soaking in a solution containing 0.25wt% acetic acid, adding 0.03wt% chitosan in the acetic acid solution, temperature control at 31°C, time for 7 minutes.

[0086] Fourth stage electrolytic oxidation I: the aluminum foil after middle treatment II is placed in a solution containing 10.5wt% boric acid, 9.8wt% phosphoric acid, 0.15wt% ammonium adipate, using ammonia to adjust the pH to 6.9-7.3, voltage is 380-480V, temperature is 61±2°C, electrolysis time is 28 minutes.

[0087] Fourth stage electrolytic oxidation II: repeating the process parameters and formula of the fourth stage electrolytic oxidation I, again electrolytic oxidation treatment.

[0088] Baking II: the aluminum foil after the fourth stage electrolytic oxidation II is sent into a baking furnace, nitrogen protection, temperature control at 265°C, baking time is 18 minutes, nitrogen flow rate is 9L / min, heating rate is 8°C / min, cooling rate is 11°C / min.

[0089] Fourth stage electrolytic oxidation III: the aluminum foil after the fourth stage electrolytic oxidation II is placed in a solution containing 10.8wt% boric acid, 10.3wt% phosphoric acid, 0.18wt% ammonium adipate, using ammonia to adjust the pH to 7.1-7.5, voltage is 430-530V, pulse mode, frequency is 250-550Hz, waveform is trapezoidal wave, duty cycle is 65%, temperature is 63±2°C, electrolysis time is 34 minutes.

[0090] Fourth stage electrolytic oxidation IV: repeating the process parameters and formula of the fourth stage electrolytic oxidation III, again electrolytic oxidation treatment.

[0091] Baking III: the aluminum foil after the fourth stage electrolytic oxidation IV is sent into a baking furnace, nitrogen protection, temperature control at 315-355°C, baking time is 28 minutes, nitrogen flow rate is 20L / min, heating rate is 13°C / min, cooling rate is 20°C / min.

[0092] Post-treatment: dipping in a 0.3wt% silane coupling agent solution, infrared radiation for 40 minutes, vacuum drying to obtain the final aluminum electrolytic capacitor anode foil.

[0093] Preparation of capacitor aluminum plastic film: maleic anhydride modified polyolefin, diisocyanate and glycidyl ether type epoxy resin are mixed in a mass ratio of 5:2:1, melted and stirred at 120°C to prepare an adhesive layer slurry, which is uniformly coated on the surface of the aluminum electrolytic capacitor formation foil by a doctor blade coating process, with a thickness controlled at 30μm, and an adhesive layer is formed after curing; then polypropylene and polyphenylene sulfide are melt blended in a mass ratio of 7:3, and a heat sealing layer film is prepared by a twin-screw extruder at 240°C, with a thickness controlled at μm, and finally the heat sealing layer is compounded on the surface of the adhesive layer by a hot pressing lamination process, with a hot pressing temperature of 180°C and a pressure of 9 MPa, and an aluminum plastic film for capacitors is obtained after cooling and setting.

[0094] Example 4:

[0095] A production method of a capacitor aluminum plastic film and an aluminum electrolytic capacitor formation foil, comprising the following steps:

[0096] Hydration treatment: after the etched aluminum foil is unwound, it is subjected to boiling water hydration treatment, using 95±2°C ultrapure water, and the treatment time is 10.5 minutes.

[0097] First-stage electrolytic oxidation: the etched aluminum foil after hydration treatment is placed in a solution of 4.1wt% boric acid, 3.1wt% phosphoric acid and 0.52wt% ammonium adipate, 0.012wt% nano titanium dioxide, 0.06wt% nano aluminum oxide and 0.11wt% polyethylene glycol are added, ammonia water is used to adjust the pH to 5.7-6.1, the voltage is 205-305V, the pulse mode frequency is 120-500Hz, the waveform is square wave, the duty cycle is 31%, the temperature is 45.5±2°C, the electrolysis time is 17 minutes, the electrolytic cell uses titanium-based coated electrodes, and the electrode spacing is 10.5mm; the electrolyte circulating flow rate is 1.1m / s, and the liquid level difference is controlled to ±2mm.

[0098] Second-stage electrolytic oxidation: the aluminum foil after the first-stage electrolytic oxidation is placed in a solution of 6.1wt% boric acid, 5.1wt% phosphoric acid and 0.32wt% ammonium adipate, ammonia water is used to adjust the pH to 6.1-6.6, the voltage is 255-355V, the temperature is 50.5±2°C, the mode is direct current, and the electrolysis time is 17 minutes.

[0099] Middle treatment I: the aluminum foil after the second-stage electrolytic oxidation is washed with deionized water, and then soaked in a solution of 0.11wt% citric acid and 0.025wt% sodium gluconate, with a temperature controlled at 36°C and a time of 5.5 minutes, and the soaking process is carried out under inert gas protection.

[0100] Third stage electrolytic oxidation: The aluminum foil from the first stage electrolytic oxidation was placed in a solution of 8.1 wt% boric acid, 7.1 wt% phosphoric acid, and 0.21 wt% ammonium adipate, with the addition of 0.055 wt% nano-zinc oxide particles. Ammonia was used to adjust the pH to 6.6-7.1. The voltage was 305-405 V, with direct current superimposed on high-frequency pulses at a frequency of 3-6 kHz and a duty cycle of 22%. The temperature was 55.5±2°C, and the electrolysis time was 21 minutes.

[0101] Feed tank treatment: The aluminum foil after the third stage electrolytic oxidation was placed in a feed tank containing a solution of 1.15 wt% ammonium adipate, 0.035 wt% polyvinylpyrrolidone, and 0.13 wt% PEG-2000. The temperature was controlled at 40.5°C, and the treatment time was 11.5 minutes. The solution was kept uniform by magnetic stirring at a rate of 120 rpm.

[0102] Baking I: The aluminum foil after the feed tank treatment was sent to a baking furnace under nitrogen protection. The temperature was controlled at 205°C, the baking time was 11 minutes, the nitrogen flow rate was 6 L / min, the heating rate was 5.5°C / min, and the cooling rate was 8°C / min.

[0103] Middle treatment II: The aluminum foil was rinsed with deionized water and then soaked in a solution containing 0.22 wt% acetic acid with the addition of 0.02 wt% chitosan. The temperature was controlled at 30.5°C, and the time was 5.5 minutes.

[0104] Fourth stage electrolytic oxidation I: The aluminum foil after the middle treatment II was placed in a solution of 10.2 wt% boric acid, 9.2 wt% phosphoric acid, and 0.11 wt% ammonium adipate. Ammonia was used to adjust the pH to 6.6-7.1. The voltage was 355-455 V, the temperature was 60.5±2°C, and the electrolysis time was 27 minutes.

[0105] Fourth stage electrolytic oxidation II: The process parameters and formulation of the fourth stage electrolytic oxidation I were repeated for the second electrolytic oxidation treatment.

[0106] Baking II: The aluminum foil after the fourth stage electrolytic oxidation II was sent to a baking furnace under nitrogen protection. The temperature was controlled at 252°C, the baking time was 16 minutes, the nitrogen flow rate was 11 L / min, the heating rate was 8°C / min, and the cooling rate was 13°C / min.

[0107] Fourth stage electrolytic oxidation III: The aluminum foil after the fourth stage electrolytic oxidation II was placed in a solution of 10.3 wt% boric acid, 9.3 wt% phosphoric acid, and 0.12 wt% ammonium adipate. Ammonia was used to adjust the pH to 6.7-7.2. The voltage was 410-510 V in pulse mode with a duty cycle of 52%. The temperature was 61±2°C, and the electrolysis time was 28 minutes.

[0108] Fourth stage electrolytic oxidation IV: repeat the process parameters and formula of the fourth stage electrolytic oxidation III, and electrolytic oxidation treatment is carried out again.

[0109] Baking III: the aluminum foil after the fourth stage electrolytic oxidation IV is sent into a baking furnace, nitrogen protection, temperature control is 302-352℃, baking time is 21 minutes, nitrogen flow rate is 16L / min, heating rate is 11℃ / min, cooling rate is 17℃ / min.

[0110] Post-treatment: immersion in 0.15wt% silane coupling agent solution, infrared radiation for 42 minutes, vacuum drying to obtain the final aluminum electrolytic capacitor formation foil.

[0111] Preparation of capacitor aluminum plastic film: maleic anhydride modified polyolefin, diisocyanate and glycidyl ether type epoxy resin are mixed in a mass ratio of 5:2:1, melted and stirred at 100℃ to prepare an adhesive layer slurry, which is uniformly coated on the surface of the aluminum electrolytic capacitor formation foil by a doctor blade coating process, and the thickness is controlled at 20μm, and an adhesive layer is formed after curing; then polypropylene and polyphenylene sulfide are melt blended in a mass ratio of 7:3, and a heat sealing layer film is prepared by a twin-screw extruder at 230℃, and the thickness is controlled at 60μm, and finally the heat sealing layer is compounded on the surface of the adhesive layer by a hot pressing lamination process, and the hot pressing temperature is 175℃, the pressure is 11Pa, and the capacitor aluminum plastic film is obtained after cooling and setting.

[0112] Example 5:

[0113] A capacitor aluminum plastic film and a production method of aluminum electrolytic capacitor formation foil, comprising the following steps:

[0114] Hydration treatment: after the etched aluminum foil is unwound, boiling water hydration treatment is carried out, and 95±2℃ ultrapure water is used, and the treatment time is 13 minutes.

[0115] First stage electrolytic oxidation: the etched aluminum foil after hydration treatment is placed in a solution of 4.3wt% boric acid, 3.3wt% phosphoric acid, 0.58wt% ammonium adipate, 0.018wt% nano titanium dioxide, 0.08wt% nano aluminum oxide and 0.14wt% polyethylene glycol, and the pH is adjusted to 5.8-6.3 using ammonia water, the voltage is 215-315V, the pulse mode frequency is 180-500Hz, the waveform is square wave, the duty cycle is 33%, the temperature is 47±2℃, the electrolysis time is 19 minutes, the electrolytic cell uses titanium-based coated electrodes, and the electrode spacing is 13mm; the electrolyte circulating flow rate is 1.3m / s, and the liquid level difference is controlled to be ±2mm.

[0116] Second stage electrolytic oxidation: The first stage electrolytic oxidized aluminum foil was placed in a solution of 6.3wt% boric acid, 5.3wt% phosphoric acid, and 0.38wt% ammonium adipate, and the pH was adjusted to 6.3-6.8 using ammonia water. The voltage was 265-365V, the temperature was 53±2℃, the direct current mode was used, and the electrolysis time was 19 minutes.

[0117] Intermediate treatment I: The second stage electrolytic oxidized aluminum foil was rinsed with deionized water, and then soaked in a solution of 0.13wt% citric acid and 0.04wt% sodium gluconate. The temperature was controlled at 39℃, and the soaking time was 6.5 minutes. The soaking process was carried out under inert gas protection.

[0118] Third stage electrolytic oxidation: The first stage electrolytic oxidized aluminum foil was placed in a solution of 8.3wt% boric acid, 7.3wt% phosphoric acid, and 0.23wt% ammonium adipate, and 0.065wt% nano-zinc oxide particles were added. The pH was adjusted to 6.9-7.3 using ammonia water. The voltage was 310-410V, the direct current superimposed high-frequency pulse mode was used, the frequency was 4-7kHz, the duty cycle was 27%, the temperature was 57±2℃, and the electrolysis time was 23 minutes.

[0119] Feeding tank treatment: The third stage electrolytic oxidized aluminum foil was placed in a feeding tank, and a solution of 1.25wt% ammonium adipate, 0.05wt% polyvinylpyrrolidone, and 0.16wt% PEG-2000 was added to the feeding tank. The temperature was controlled at 43℃, the treatment time was 13 minutes, and the solution was kept uniform by magnetic stirring at a stirring rate of 130rpm.

[0120] Baking I: The feeding tank treated aluminum foil was sent to a baking furnace under nitrogen protection. The temperature was controlled at 225℃, the baking time was 13 minutes, the nitrogen flow rate was 9L / min, the heating rate was 6.5℃ / min, and the cooling rate was 10℃ / min.

[0121] Intermediate treatment II: The aluminum foil was rinsed with deionized water, and then soaked in a solution containing 0.28wt% acetic acid and 0.035wt% chitosan. The temperature was controlled at 33℃, and the soaking time was 8 minutes.

[0122] Fourth stage electrolytic oxidation I: The intermediate treatment II treated aluminum foil was placed in a solution of 10.8wt% boric acid, 9.5wt% phosphoric acid, and 0.13wt% ammonium adipate. The pH was adjusted to 6.9-7.4 using ammonia water. The voltage was 365-465V, the temperature was 63±2℃, and the electrolysis time was 31 minutes.

[0123] Fourth stage electrolytic oxidation II: The process parameters and formula of the fourth stage electrolytic oxidation I were repeated for the second electrolytic oxidation treatment.

[0124] Baking Ⅱ: The aluminum foil after the fourth stage of electrolytic oxidation Ⅱ was sent into the baking furnace, protected by nitrogen, the temperature was controlled at 275℃, the baking time was 22 minutes, the nitrogen flow rate was 14 L / min, the heating rate was 9℃ / min, and the cooling rate was 16℃ / min.

[0125] Fourth stage of electrolytic oxidation Ⅲ: The aluminum foil after the fourth stage of electrolytic oxidation Ⅱ was placed in a solution of 11.2wt% boric acid, 10.2wt% phosphoric acid, and 0.15wt% ammonium adipate, the pH was adjusted to 7.2-7.6 using ammonia water, the voltage was 420-520V, the pulse mode was used, the duty cycle was 55%, the temperature was 66±2℃, and the electrolysis time was 35 minutes.

[0126] Fourth stage of electrolytic oxidation Ⅳ: The process parameters and formula of the fourth stage of electrolytic oxidation Ⅲ were repeated, and the electrolytic oxidation treatment was performed again.

[0127] Baking Ⅲ: The aluminum foil after the fourth stage of electrolytic oxidation Ⅳ was sent into the baking furnace, protected by nitrogen, the temperature was controlled at 310-360℃, the baking time was 29 minutes, the nitrogen flow rate was 21 L / min, the heating rate was 14℃ / min, and the cooling rate was 22℃ / min.

[0128] Post-processing: Immersion in a 0.2wt% silane coupling agent solution, infrared radiation for 55 minutes, vacuum drying to obtain the final aluminum electrolytic capacitor formation foil.

[0129] Post-processing: Immersion in a 0.3% silane coupling agent solution, infrared radiation for 40 minutes, vacuum drying to obtain the final aluminum electrolytic capacitor formation foil.

[0130] Preparation of capacitor aluminum plastic film: Maleic anhydride modified polyolefin, diisocyanate, and glycidyl ether type epoxy resin were mixed in a mass ratio of 5:2:1, melted and stirred at 95℃ to prepare an adhesive layer slurry, which was uniformly coated on the surface of the aluminum electrolytic capacitor formation foil by a doctor blade coating process, with a thickness control of 25μm, and an adhesive layer was formed after curing; then polypropylene and polyphenylene sulfide were melt blended in a mass ratio of 7:3, and a heat sealing layer film was prepared by a twin-screw extruder at 220℃, with a thickness control of 60μm, and finally the heat sealing layer was compounded on the surface of the adhesive layer by a hot press lamination process, with a hot press temperature of 175℃ and a pressure of 10 MPa, and a capacitor aluminum plastic film was obtained after cooling and setting.

[0131] It should be noted that boric acid, as a weak acid buffer, controls the pH stability of the electrolyte, participates in the lattice construction of the oxide film Al2O3, and improves the dielectric strength.

[0132] It should be noted that phosphoric acid can enhance the ionic conductivity of the electrolyte, promote the formation of porous oxide film, and H2PO4~ ions can be inserted into the oxide film structure to improve corrosion resistance.

[0133] It should be noted that the concentration of boric acid from 4% to 10%, the concentration of phosphoric acid from 3% to 9%, segmented matching voltage, the realization of oxide film gradient growth.

[0134] It should be noted that the nano TiO2 in the oxide layer forms a heterogeneous nucleation point, reducing the crystallization potential barrier of the oxide film.

[0135] It should be noted that the nano Al2O 3， Fill the micropores of the oxide film, improve the surface flatness, and improve the breakdown voltage.

[0136] It should be noted that the nano ZnO introduces semiconductor properties in the third stage of oxidation, optimizing dielectric loss.

[0137] It should be noted that polyethylene glycol (PEG): through the steric hindrance effect of nanoparticles dispersion, reduce the surface tension of electrolyte, prevent the agglomeration of nanoparticles, ensure the uniformity of electrolyte, so as to improve the quality of oxide film.

[0138] It should be noted that polyvinylpyrrolidone (PVP): form a molecular chain network in the feeding tank, repair the microcracks of the oxide film.

[0139] It should be noted that chitosan through the coordination of-NH2 and Al-OH, build organic-inorganic hybrid interface layer.

[0140] It should be noted that ammonium adipate provides NH4 + Inhibit hydrogen evolution reaction, adipate chelate Al 3+ Control the crystallization rate.

[0141] It should be noted that citric acid chelates metal impurity ions, and modifies the surface of the oxide film through carboxyl groups.

[0142] Comparative example 1:

[0143] A capacitor aluminum plastic film and a production method of aluminum electrolytic capacitor formation foil, comprising the following steps:

[0144] Hydration treatment: after the etched aluminum foil is unwound, boiling water hydration treatment is carried out, 95±2℃ ultrapure water is used, and the treatment time is 10-12min, forming a pre-oxidation layer.

[0145] First stage electrolytic oxidation: the etched aluminum foil after hydration treatment is placed in a solution of 4.0wt% boric acid, 3.0wt% phosphoric acid and 0.5wt% ammonium adipate, without adding nano titanium dioxide, nano aluminum oxide and polyethylene glycol, using ammonia water to adjust the pH to 5.5-6.0, the voltage is 200-300V, the pulse mode, the duty cycle is 30%, the temperature is 45±2℃, and the electrolysis time is 15-20min.

[0146] Second stage electrolytic oxidation: the aluminum foil after the first stage electrolytic oxidation is placed in a solution of 6.0wt% boric acid, 5.0wt% phosphoric acid and 0.3wt% ammonium adipate, the pH is adjusted to 6.0-6.5 using ammonia water, the voltage is 250-350V, the temperature is 50±2℃, and the electrolysis time is 15-20min.

[0147] Intermediate treatment I: the aluminum foil after the second stage electrolytic oxidation is subjected to intermediate treatment, is washed with deionized water, and then is soaked in a solution of 0.1wt%-0.5wt% citric acid and 0.02wt%-0.06wt% sodium gluconate, the temperature is controlled at 35-40℃, and the time is 5-10min.

[0148] Third stage electrolytic oxidation: the aluminum foil after the first stage electrolytic oxidation is placed in a solution of 8.0wt% boric acid, 7.0wt% phosphoric acid and 0.2wt% ammonium adipate, no nano-zinc oxide particles are added, the pH is adjusted to 6.5-7.0 using ammonia water, the voltage is 300-400V, direct current is superimposed with high-frequency pulse, the temperature is 55±2℃, and the electrolysis time is 20-25min.

[0149] Power feeding tank treatment: the aluminum foil after the third stage electrolytic oxidation is placed in a power feeding tank, 1.0wt%-2.0wt% ammonium adipate, 0.02wt%-0.05wt% polyvinylpyrrolidone and 0.1wt%-0.3wt% PEG-200 are added in the power feeding tank, the temperature is controlled at 40-45℃, and the treatment time is 10-17min.

[0150] Baking I: the aluminum foil after the power feeding tank treatment is sent into a baking furnace, is protected by nitrogen, the temperature is controlled at 200-250℃, and the baking time is 25-30min.

[0151] Intermediate treatment II: the aluminum foil is washed with deionized water, and then is soaked in a solution of 0.2wt%-0.5wt% acetic acid, no chitosan is added in the acetic acid solution, the temperature is controlled at 30-35℃, and the time is 5-9min.

[0152] Fourth stage electrolytic oxidation I: the aluminum foil after the intermediate treatment II is placed in a solution of 10.0wt% boric acid, 9.0wt% phosphoric acid and 0.1wt% ammonium adipate, the pH is adjusted to 6.5-7.0 using ammonia water, the voltage is 350-450V, the temperature is 60±2℃, and the electrolysis time is 25-30min.

[0153] Fourth stage electrolytic oxidation II: the process parameters and formula of the fourth stage electrolytic oxidation I are repeated, and the aluminum foil is subjected to electrolytic oxidation treatment again.

[0154] Baking II: the aluminum foil after the fourth stage electrolytic oxidation II is sent into a baking furnace, is protected by nitrogen, the temperature is controlled at 250-300℃, and the baking time is 15-35min.

[0155] Fourth stage electrolytic oxidation III: repeat the process parameters and formula of the fourth stage electrolytic oxidation I, and electrolytic oxidation treatment is carried out again.

[0156] Fourth stage electrolytic oxidation IV: the aluminum foil of the fourth stage electrolytic oxidation III is placed in a solution of 10.0wt% boric acid, 9.0wt% phosphoric acid and 0.1wt% ammonium adipate, and the pH is adjusted to 6.5-7.0 using ammonia water, the voltage is 400-500V, the pulse mode is used, the duty cycle is 50%, the temperature is 60±2℃, and the electrolysis is carried out for 25-30min.

[0157] Roasting III: the aluminum foil subjected to the fourth stage electrolytic oxidation IV is sent into a roasting furnace, the temperature is controlled at 300℃-350℃ under nitrogen protection, and the roasting time is 20-40min.

[0158] Post-treatment: immersion in a 0.1wt%-0.3wt% silane coupling agent solution, infrared radiation for 30-50min, wavelength 3-5μm, and vacuum drying to obtain the final formation foil of aluminum electrolytic capacitor.

[0159] Preparation of capacitor aluminum-plastic film: maleic anhydride modified polyolefin, diisocyanate and glycidyl ether type epoxy resin are mixed in a mass ratio of 5:2:1, and a bonding layer slurry is prepared by melt stirring at 115℃, which is uniformly coated on the surface of the formation foil of aluminum electrolytic capacitor by a doctor blade coating process, and the thickness is controlled at 30μm, and a bonding layer is formed after curing; then polypropylene and polyphenylene sulfide are melt blended in a mass ratio of 7:3, and a heat sealing layer film is prepared by a twin-screw extruder at 200-240℃, and the thickness is controlled at 80μm, and finally the heat sealing layer is compounded on the surface of the bonding layer by a hot pressing lamination process, and the hot pressing temperature is 170℃, the pressure is 11 MPa, and the capacitor aluminum-plastic film is obtained after cooling and setting.

[0160] Comparative example 2:

[0161] A production method of a capacitor aluminum-plastic film and a formation foil of aluminum electrolytic capacitor, comprising the following steps:

[0162] Hydration treatment: after the etched aluminum foil is unwound, boiling water hydration treatment is carried out, and 95±2℃ ultrapure water is used, and the treatment time is 10min.

[0163] First-stage electrolytic oxidation: The corrosion-treated aluminum foil is placed in a solution of 4.0 wt% boric acid, 3.0 wt% phosphoric acid and 0.5 wt% ammonium adipate, with 0.01 wt% nano-titanium dioxide, 0.05 wt% nano-aluminum oxide and 0.1 wt% polyethylene glycol added, and the pH is adjusted to 5.5-6.0 using ammonia water, the voltage is 200-300 V, the pulse mode frequency is 100-500 Hz, the waveform is square wave, the duty cycle is 30%, the temperature is 45±2°C, and the electrolysis time is 15 minutes, with a titanium-based coated electrode used in the electrolytic cell and an electrode spacing of 10 mm; the electrolyte circulation flow rate is 0.5 m / s, and the liquid level difference is controlled to ±2 mm.

[0164] Second-stage electrolytic oxidation: The aluminum foil from the first-stage electrolytic oxidation is placed in a solution of 6.0 wt% boric acid, 5.0 wt% phosphoric acid and 0.3 wt% ammonium adipate, and the pH is adjusted to 6.0-6.5 using ammonia water, the voltage is 250-350 V, the temperature is 50±2°C, and the electrolysis time is 15 minutes.

[0165] Intermediate treatment I: The aluminum foil from the second-stage electrolytic oxidation is rinsed with deionized water and then soaked in a solution of 0.1 wt% citric acid and 0.01 wt% sodium gluconate at a temperature of 35°C for 5 minutes.

[0166] The soaking process is carried out under inert gas protection.

[0167] Third-stage electrolytic oxidation: The aluminum foil from the first-stage electrolytic oxidation is placed in a solution of 8.0 wt% boric acid, 7.0 wt% phosphoric acid and 0.2 wt% ammonium adipate, with 0.05 wt% nano-zinc oxide particles added, and the pH is adjusted to 6.5-7.0 using ammonia water, the voltage is 300-400 V, the direct current is superimposed with high-frequency pulses, the frequency is 2-5 kHz, the duty cycle is 20%, the temperature is 55±2°C, and the electrolysis time is 20 minutes.

[0168] Baking I: The aluminum foil from the power supply tank treatment is sent to a baking furnace under nitrogen protection, the temperature is controlled at 200°C, the baking time is 10 minutes, the nitrogen flow rate is 5 L / min, the heating rate is 5°C / min, and the cooling rate is 8°C / min.

[0169] Intermediate treatment II: The aluminum foil is rinsed with deionized water and then soaked in a solution containing 0.2 wt% acetic acid with 0.01 wt% chitosan added, at a temperature of 30°C for 5 minutes.

[0170] Fourth-stage electrolytic oxidation I: The aluminum foil from the intermediate treatment II is placed in a solution of 10.0 wt% boric acid, 9.0 wt% phosphoric acid and 0.1 wt% ammonium adipate, and the pH is adjusted to 6.5-7.0 using ammonia water, the voltage is 350-450 V, the temperature is 60±2°C, and the electrolysis time is 25 minutes.

[0171] Fourth stage electrolytic oxidation II: repeat the process parameters and formula of the fourth stage electrolytic oxidation I, and electrolytic oxidation treatment again.

[0172] Roasting II: the aluminum foil after the fourth stage electrolytic oxidation II is sent into the roasting furnace, nitrogen protection, temperature control at 250℃, roasting time is 15 minutes, nitrogen flow rate is 10L / min, heating rate is 8℃ / min, cooling rate is 12℃ / min.

[0173] Fourth stage electrolytic oxidation III: the aluminum foil after the fourth stage electrolytic oxidation II is placed in 10.0wt% boric acid, 9.0wt% phosphoric acid, 0.1wt% ammonium adipate solution, using ammonia to adjust pH to 6.5-7.0, voltage is 400-500V, pulse mode, duty cycle 50%, temperature is 60±2℃, electrolytic time is 25 minutes.

[0174] Fourth stage electrolytic oxidation IV: repeat the process parameters and formula of the fourth stage electrolytic oxidation III, and electrolytic oxidation treatment again.

[0175] Roasting III: the aluminum foil after the fourth stage electrolytic oxidation IV is sent into the roasting furnace, nitrogen protection, temperature control at 300-350℃, roasting time is 20 minutes, nitrogen flow rate is 15L / min, heating rate is 10℃ / min, cooling rate is 15℃ / min.

[0176] Post-processing: dipping 0.1wt% silane coupling agent solution, infrared radiation for 30 minutes, vacuum drying to obtain the final aluminum electrolytic capacitor formed foil.

[0177] Preparation of capacitor aluminum plastic film: maleic anhydride modified polyolefin, diisocyanate and glycidyl ether type epoxy resin are mixed in a mass ratio of 5:2:1 to prepare an adhesive layer slurry by melting and stirring at 115℃, which is uniformly coated on the surface of the aluminum electrolytic capacitor formed foil by the scraping process, and the thickness is controlled at 30μm, and an adhesive layer is formed after curing; then polypropylene and polyphenylene sulfide are melt blended in a mass ratio of 7:3, and a heat sealing layer film is prepared by a twin-screw extruder at 200-240℃, and the thickness is controlled at 80μm, and finally the heat sealing layer is compounded on the surface of the adhesive layer by hot pressing lamination process, and the hot pressing temperature is 170℃, the pressure is 11 MPa, and the capacitor aluminum plastic film is obtained after cooling and setting.

[0178] The capacitor aluminum plastic films obtained in Examples 1-5 and Comparative Examples 1-2 are tested for various parameters, and the test method is based on EIAJ RC-2364A, Tr'120 represents the pressure rise time after boiling for 120 minutes, and the test parameters are listed in Table 1.

[0179] Table 1

[0180]

[0181] While embodiments of the application have been shown and described, it is to be understood that the application is not limited to the details of the embodiments described, since numerous changes, modifications, substitutions and variations can be made thereto without departing from the spirit and scope of the application as defined by the appended claims and their equivalents.

Claims

1. A method for producing an aluminum electrolytic capacitor formation foil, characterized by, The method comprises the following steps: hydration treatment: after the corrosion aluminum foil is unwound, boiling water hydration treatment is carried out; first-stage electrolytic oxidation: the aluminum foil after the hydration treatment is placed in a solution of 4.0wt% boric acid, 3.0wt% phosphoric acid and 0.5wt% ammonium adipate, 0.01wt%-0.03wt% nano titanium dioxide is added, 0.05wt%-0.1wt% nano aluminum oxide is added, 0.1wt% polyethylene glycol is added, ammonia water is used to adjust the pH to 5.5-6.0, the voltage is 200-300V, the pulse mode is used, the duty cycle is 30%, the temperature is 45±2℃, and electrolysis is carried out for 15-20min; second-stage electrolytic oxidation: the aluminum foil after the first-stage electrolytic oxidation is placed in a solution of 6.0wt% boric acid, 5.0wt% phosphoric acid and 0.3wt% ammonium adipate, and electrolysis is carried out for 15-20min; middle treatment I: the aluminum foil after the second-stage electrolytic oxidation is subjected to the middle treatment, the temperature is controlled to be 35-40℃, and the time is 5-10min; third-stage electrolytic oxidation: the aluminum foil after the middle treatment I is placed in a solution of 8.0wt% boric acid, 7.0wt% phosphoric acid and 0.2wt% ammonium adipate, 0.02wt%-0.06wt% nano zinc oxide particles are added, ammonia water is used to adjust the pH to 6.5-7.0, the voltage is 300-400V, direct current is superimposed with high-frequency pulse, the temperature is 55±2℃, and electrolysis is carried out for 20-25min; feeding tank treatment: the aluminum foil after the third-stage electrolytic oxidation is placed in a feeding tank, the temperature is controlled to be 40-45℃, and the treatment time is 10-17min; calcination I: the aluminum foil after the feeding tank treatment is sent into a calcination furnace, the temperature is controlled to be 200-250℃, and the calcination time is 25-30min; middle treatment II: the aluminum foil after the calcination I treatment is soaked in a solution containing 0.2wt%-0.5wt% acetic acid, the temperature is controlled to be 30-35℃, and the time is 5-9min; fourth-stage electrolytic oxidation I: the aluminum foil after the middle treatment II is placed in a solution of 10.0wt% boric acid, 9.0wt% phosphoric acid and 0.1wt% ammonium adipate, and electrolysis is carried out for 25-30min; fourth-stage electrolytic oxidation II: the process parameters and formula of the fourth-stage electrolytic oxidation I are repeated, and electrolytic oxidation treatment is carried out again; calcination II: the aluminum foil after the fourth-stage electrolytic oxidation II is sent into a calcination furnace, the temperature is controlled to be 250-300℃, and the calcination time is 15-35min; fourth-stage electrolytic oxidation III: the process parameters and formula of the fourth-stage electrolytic oxidation I are repeated, and electrolytic oxidation treatment is carried out again; fourth-stage electrolytic oxidation IV: the aluminum foil after the fourth-stage electrolytic oxidation III is placed in a solution of 10.0wt% boric acid, 9.0wt% phosphoric acid and 0.1wt% ammonium adipate, and electrolysis is carried out for 25-30min; calcination III: the aluminum foil after the fourth-stage electrolytic oxidation IV is sent into a calcination furnace, the temperature is controlled to be 300-350℃, and the calcination time is 20-40min; post-treatment: the aluminum foil is immersed in a solution of 0.1wt%-0.3wt% silane coupling agent, infrared radiation is carried out for 30-50min, the wavelength is 3-5μm, and vacuum drying is carried out to obtain the final aluminum electrolytic capacitor forming foil.

2. The production method of an aluminum electrolytic capacitor formation foil according to claim 1, characterized by: The second stage electrolytic oxidation uses ammonia to adjust pH to 6.0-6.5, voltage is 250-350V, temperature is 50±2℃, and electrolysis time is 15-20min; The fourth stage electrolytic oxidation I uses ammonia to adjust pH to 6.5-7.0, voltage is 350-450V, temperature is 60±2℃; The fourth stage electrolytic oxidation IV uses ammonia to adjust pH to 6.5-7.0, voltage is 400-500V, pulse mode, duty cycle is 50%, and temperature is 60±2℃.

3. The method of producing a formation foil for an aluminum electrolytic capacitor according to claim 1, characterized by: The intermediate treatment I uses deionized water to rinse, and then is soaked in 0.1wt%-0.5wt% citric acid and 0.02wt%-0.06wt% sodium gluconate solution; the feeding tank treatment adds 1.0wt%-2.0wt% ammonium adipate, 0.02wt%-0.05wt% polyvinylpyrrolidone and 0.1wt%-0.3wt% PEG200 solution; the intermediate treatment II adds 0.01wt%-0.03wt% chitosan, and nitrogen protection is used in calcination I, calcination II and calcination III.

4. The method of producing an aluminum electrolytic capacitor formation foil according to claim 1, characterized by: In all electrolytic oxidation steps, titanium-based coated electrodes are used in electrolytic cell, electrode spacing is 10-30mm; electrolyte circulation flow rate is 0.5-2.0m / s, and liquid level difference is controlled to ±2mm.

5. The method for producing aluminum electrolytic capacitor formed foil according to claim 2, wherein: The particle size of the nano-titanium dioxide is 10-50nm, and the particle size of the nano-aluminum oxide is 20-80nm.

6. The method for producing aluminum electrolytic capacitor formed foil according to claim 3, wherein: The pH value of the sodium gluconate solution used in the intermediate treatment I is 3.5-4.5, and the soaking process in the intermediate treatment I is carried out under inert gas protection.

7. The method for producing aluminum electrolytic capacitor formed foil according to claim 1, wherein: In the third stage electrolytic oxidation, the frequency of the high-frequency pulse is 2-5kHz, and the duty cycle is 20%-40%; the particle size of the nano-zinc oxide particles is 30-100nm.

8. The method of claim 3, wherein: the aluminum electrolytic capacitor formation foil is produced by the steps of: providing an aluminum foil; anodizing the aluminum foil to form an anodized aluminum foil; and etching the anodized aluminum foil to form the aluminum electrolytic capacitor formation foil. In the feeding tank treatment, the molecular weight of the polyvinylpyrrolidone is 10000-50000.

9. The method of claim 3, wherein: the aluminum electrolytic capacitor formation foil is produced by the steps of: providing an aluminum foil; anodizing the aluminum foil to form an anodized aluminum foil; and etching the anodized aluminum foil to form the aluminum electrolytic capacitor formation foil. In the calcination I, calcination II and calcination III, the gas flow rate of the nitrogen protection is 5-15L / min; The heating rate is 5-10℃ / min, and the cooling rate is 8-15℃ / min.

10. A capacitor laminate film, characterized by: It comprises, from inside to outside, an aluminum electrolytic capacitor formed foil, an adhesive layer and a heat-sealing layer; The adhesive layer is an adhesive composed of maleic anhydride modified polyolefin, diisocyanate and glycidyl ether type epoxy resin; The heat-sealing layer is composed of polypropylene and polyphenylene sulfide; The aluminum electrolytic capacitor formed foil is produced by the method of claim 1.

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