Composite adhesive tape for binding core package, preparation method and aluminum electrolytic capacitor

Abstract

A composite adhesive tape for binding a core package comprises a porous base material layer and a functional adhesive layer, the functional adhesive layer is coated on the base material layer in a latticed shape, the distance between lines is larger than 200 micrometers and smaller than 1000 micrometers, and the width of the lines ranges from 100 micrometers to 500 micrometers. The porous base material layer comprises one or more of wood pulp, hemp pulp, cotton pulp, straw pulp or artificial fiber; the porous base material layer is subjected to pore expanding treatment by being soaked in a NaOH solution with the weight concentration of 3%-8%, and the porosity of the porous base material layer is 35%-40%. The composite adhesive tape for binding the core cladding can realize the functions of high-strength fixation, high-temperature stability, vibration resistance and efficient electrolyte adsorption of the core cladding.

Description

Technical Field

[0001] The invention relates to a composite adhesive tape, in particular to a composite adhesive tape for a binding core package and a preparation method thereof. Background Art

[0002] Aluminum electrolytic capacitors are core components of electronic devices. Their cores consist of anode foil, cathode foil, and separator paper secured with tape and then encapsulated in an aluminum shell. Currently, the industry generally uses PP (polypropylene) or PPS (polyphenylene sulfide) tape to secure the cores, but this has the following technical drawbacks: Single function: Traditional tape only achieves mechanical fixation, and electrolyte adsorption relies on an independent isolation paper layer, resulting in a complex core package structure and increased thickness (the total thickness increases by 15%-20% after stacking); Insufficient high-temperature performance: PP tape has a heat-resistant temperature of ≤120°C and a shrinkage rate of >2% at high temperatures, which may cause the core package to loosen and cause capacity attenuation; Poor vibration resistance: In a vibrating environment (such as in a vehicle), the adhesive strength of the tape decreases by more than 40%, and the loose core package causes capacity decay. Uneven electrolyte distribution: The area covered by the tape forms an "adsorption blind spot", the electrolyte infiltration efficiency is reduced by 50%, and the capacitor activation time is prolonged. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a composite adhesive tape for a binding core package and a preparation method thereof.

[0004] To solve the above technical problems, the present invention proposes a technical solution: a composite tape for a restraining core package, comprising a porous substrate layer and a functional adhesive layer, wherein the functional adhesive layer is coated on the substrate layer in a grid pattern, with a line spacing greater than 200 μm and less than 1000 μm, and a line width between 100 μm and 500 μm; the porous substrate layer comprises one or more of wood pulp, hemp pulp, cotton pulp, straw pulp or artificial fiber; the porous substrate layer is pore-expanded by immersing it in a NaOH solution with a weight concentration of 3% to 8%, and the porosity of the porous substrate layer is between 35% and 40%.

[0005] In the composite tape for binding core wrapping, preferably, the surface of the porous substrate layer is treated by plasma etching to form micron-scale grooves on the surface of the porous substrate layer.

[0006] In the composite adhesive tape for binding core wrapping, preferably, the functional adhesive layer comprises 60-80 parts by weight of polyimide resin, 5-15 parts by weight of nano-silica modified acrylic adhesive, and 3-8 parts by weight of carbon fiber.

[0007] In the composite adhesive tape for the binding core package, preferably, the functional adhesive is coated on one surface of the porous substrate layer to form a functional adhesive layer, and the coverage of the functional adhesive on the surface of the porous substrate layer is between 60% and 90%.

[0008] A method for preparing a composite adhesive tape for a binding core package comprises the following steps: 1) Preparation of porous substrate layer; ① Evenly mix one or more pulps of wood pulp, hemp pulp, cotton pulp, straw pulp or man-made fiber; ② The mixed slurry in step ① is made into release paper, the thickness of the release paper is 30-50 μm, and the basis weight is between 50 g / m² and 90 g / m²; ③ Immerse the release paper from step ② in a NaOH solution with a weight concentration of 3% to 8% for 5 to 20 minutes to perform pore expansion treatment; the temperature of the NaOH solution is between 50° C. and 80° C.; ④ The surface of the release paper after the treatment in step ③ is subjected to plasma etching to form micron-sized grooves on the surface of the porous substrate layer; 2) Preparation of functional adhesive layer; I. 60-80 parts by weight of a polyimide resin, 5-15 parts by weight of a nano-silica modified acrylic adhesive, and 3-8 parts by weight of carbon fiber are uniformly mixed to form a functional adhesive; II. The functional glue is coated on the surface of the porous substrate layer, the line spacing is greater than 200μm and less than 1000μm, and the line width is between 100μm and 500μm.

[0009] In the above-mentioned method for preparing the composite adhesive tape for the binding core package, preferably, the functional adhesive is coated on one surface of the porous substrate layer to form a functional adhesive layer, and the coverage of the functional adhesive on the surface of the porous substrate layer is between 60% and 98%.

[0010] An aluminum electrolytic capacitor comprises a core package and a shell, wherein the core package is sealed in the shell by a rubber plug or a cover plate; the outermost layer of the core package is fixed by wrapping the composite adhesive tape for binding the core package.

[0011] Compared with the prior art, the advantages of the present invention are that the composite adhesive tape for restraining the core package of the present invention can achieve the functions of high-strength fixation of the core package, high-temperature stability, anti-vibration performance and efficient adsorption of electrolyte. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 Schematic diagram of the structure of the composite tape used for binding the core package in Example 1.

[0013] Legend 1. Porous substrate layer; 2. Functional adhesive layer. DETAILED DESCRIPTION

[0014] In order to facilitate understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with preferred embodiments, but the protection scope of the present invention is not limited to the following specific embodiments.

[0015] It should be noted that when an element is described as being "fixed, fixed, connected or communicated with" another element, it can be directly fixed, fixed, connected or communicated with the other element, or it can be indirectly fixed, fixed, connected or communicated with the other element through other intermediate connectors.

[0016] Unless otherwise defined, all technical terms used hereinafter have the same meanings as those generally understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Example 1

[0017] like Figure 1 The composite tape for core wrapping shown in the figure comprises a porous substrate layer 1 and a functional adhesive layer 2. The functional adhesive layer 2 is applied to the substrate layer in a grid pattern, with line spacing greater than 200 μm and less than 1000 μm, preferably 500 μm, and line widths between 100 μm and 500 μm, preferably 200 μm. The functional adhesive is applied to one surface of the porous substrate layer to form the functional adhesive layer, with the coverage of the functional adhesive on the porous substrate layer ranging from 60% to 98%.

[0018] The porous substrate layer is made of one or more of wood pulp, hemp pulp, cotton pulp, straw pulp, or man-made fibers. In this embodiment, the porous substrate layer 1 is made of wood pulp and aramid fiber, with the weight ratio of wood pulp to aramid fiber being between 1:1 and 2:1. The porous substrate layer is treated by immersing it in a 3% to 8% NaOH solution to expand its pores, resulting in a porosity of 35% to 40%. In this embodiment, the total thickness of the composite tape is between 40 and 80 μm, and the thickness of the porous substrate layer is between 30 and 50 μm.

[0019] In this embodiment, the surface of the porous substrate layer 1 is subjected to plasma etching to form micron-scale grooves on the surface of the porous substrate layer 1. During the surface plasma etching process, the power is 80 W and the time is about 60 seconds.

[0020] In this embodiment, the functional adhesive layer 2 includes 60-80 parts by weight of polyimide resin, 5-15 parts by weight of nano-silicon dioxide modified acrylic adhesive, and 3-8 parts by weight of carbon fiber.

[0021] In this embodiment, the functional adhesive can withstand heat up to 180°C, with a thermal shrinkage of less than or equal to 0.5%; and the bonding strength can reach 5.5 N / cm. Since the functional adhesive is coated on one surface of the porous substrate layer, the coverage of the functional adhesive on the surface of the porous substrate layer is between 60% and 98%. In this way, the porous substrate layer can effectively adsorb the electrolyte through the gaps in the functional adhesive layer, thereby improving the adsorption efficiency. The adsorption efficiency refers to the percentage of the mass of electrolyte adsorbed per unit area of ​​the tape to the adsorption capacity of the same area of ​​standard electrolytic paper. According to the JIS C 6481 standard test (immersion centrifugation method), the electrolytic paper composite tape of the present invention has a porosity of 35%-40% after alkali treatment and is plasma-etched to form micron grooves and a grid adhesive layer design, resulting in an adsorption efficiency of 85%, compared to only 32% for conventional tapes, achieving rapid and uniform electrolyte infiltration and adsorption.

[0022] This embodiment also provides a method for preparing a composite adhesive tape for a binding core package, comprising the following steps: 1) Preparation of porous substrate layer; ① Evenly mix one or more pulps of wood pulp, hemp pulp, cotton pulp, straw pulp or man-made fiber; ② The mixed slurry in step ① is made into release paper, the thickness of the release paper is 30-50 μm, and the basis weight is between 50 g / m² and 90 g / m²; ③ Immerse the release paper from step ② in a NaOH solution with a weight concentration of 3% to 8% for 5 to 20 minutes to perform pore expansion treatment; the temperature of the NaOH solution is between 50° C. and 80° C.; ④ The surface of the release paper after the treatment in step ③ is subjected to plasma etching to form micron-scale grooves on the surface of the porous substrate layer; 2) Preparation of functional adhesive layer; I. 60-80 parts by weight of a polyimide resin, 5-15 parts by weight of a nano-silica modified acrylic adhesive, and 3-8 parts by weight of carbon fiber are uniformly mixed to form a functional adhesive; II. Coating the functional adhesive on the surface of the porous substrate layer, with line spacing greater than 200 μm and less than 1000 μm, and line width between 100 μm and 500 μm. The functional adhesive is coated on one surface of the porous substrate layer, and the coverage of the functional adhesive on the porous substrate layer is between 60% and 98%.

[0023] This embodiment also provides an aluminum electrolytic capacitor, including a core package and a shell. The core package is sealed in the shell by a rubber plug or a cover plate; the outermost layer of the core package is fixed by wrapping the composite tape for binding the core package of this embodiment.

[0024] The composite adhesive tape for restraining the core package of this embodiment can achieve the functions of high-strength fixation of the core package, high-temperature stability, anti-vibration performance, and efficient adsorption of the electrolyte.

[0025] In order to verify the performance of the composite tape for the binding core package in Example 1, a traditional PP tape was used as a control group, and their heat resistance, bonding strength, vibration resistance, and adsorption efficiency were tested respectively; the results are shown in the following table: .

[0026] The test methods and criteria for heat resistance, bonding strength, vibration resistance and adsorption efficiency are shown in the following table: .

Claims

1. A composite tape for a binding core package, characterized in that: The invention comprises a porous substrate layer and a functional adhesive layer, wherein the functional adhesive layer is coated on the substrate layer in a grid shape, the line spacing is greater than 200 μm and less than 1000 μm, and the line width is between 100 μm and 500 μm; the porous substrate layer comprises one or more of wood pulp, hemp pulp, cotton pulp, straw pulp or artificial fiber; the porous substrate layer is pore-expanded by immersing in a NaOH solution with a weight concentration of 3% to 8%, and the porosity of the porous substrate layer is between 35% and 40%.

2. The composite adhesive tape for binding core wrap according to claim 1, characterized in that: The surface of the porous substrate layer is treated by plasma etching to form micron-scale grooves on the surface of the porous substrate layer.

3. The composite adhesive tape for binding core wrap according to claim 1, characterized in that: The functional adhesive layer comprises 60-80 parts by weight of polyimide resin, 5-15 parts by weight of nano-silicon dioxide modified acrylic adhesive and 3-8 parts by weight of carbon fiber.

4. The composite adhesive tape for binding core wrap according to claim 1, characterized in that: The functional adhesive is coated on one surface of the porous substrate layer to form a functional adhesive layer, and the coverage of the functional adhesive on the surface of the porous substrate layer is between 60% and 98%.

5. The method for preparing the composite adhesive tape for the binding core package according to claim 1, wherein: The following steps are included: 1) Preparation of porous substrate layer; ① Evenly mix wood pulp and aramid fiber to form a mixed slurry, with the weight ratio of wood pulp to aramid fiber being between 1:1 and 2:1; ② The mixed slurry in step ① is made into release paper, the thickness of the release paper is 30-50 μm, and the basis weight is between 50 g / m² and 90 g / m²; ③ Immerse the release paper from step ② in a NaOH solution with a weight concentration of 3% to 8% for 5 to 20 minutes to perform pore expansion treatment; the temperature of the NaOH solution is between 50° C. and 80° C.; ④ The surface of the release paper after the treatment in step ③ is subjected to plasma etching to form micron-sized grooves on the surface of the porous substrate layer; 2) Preparation of functional adhesive layer; I. 60-80 parts by weight of a polyimide resin, 5-15 parts by weight of a nano-silica modified acrylic adhesive, and 3-8 parts by weight of carbon fiber are uniformly mixed to form a functional adhesive; II. The functional glue is coated on the surface of the porous substrate layer, the line spacing is greater than 200μm and less than 1000μm, and the line width is between 100μm and 500μm.

6. The method for preparing the composite adhesive tape for the binding core package according to claim 4, characterized in that: The functional adhesive is coated on one surface of the porous substrate layer to form a functional adhesive layer, and the coverage of the functional adhesive on the surface of the porous substrate layer is between 60% and 98%.

7. An aluminum electrolytic capacitor comprising a core pack and a shell, wherein the core pack is sealed in the shell by a rubber plug or a cover plate; characterized in that: The outermost layer of the core package is fixed by wrapping the composite adhesive tape for restraining the core package according to claim 1 to claim 4.

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