Etching method of bendable resistor

Abstract

The invention relates to the technical field of electronic resistor manufacturing, in particular to an etching method of a bendable resistor, which comprises the following steps: S1, selecting a stainless steel material, performing high-temperature cleaning treatment on the surface, and detecting that the stainless steel surface reaches 52 # standard by using a dyne pen; s2, carrying out double-sided screen printing on the stainless steel material, carrying out optical analysis by adopting LDI exposure, and carrying out developing molding to obtain the stainless steel material with a circuit; s3, etching liquid is sprayed to the stainless steel material with the circuit through an upper spraying disc and a lower spraying disc, etching is conducted, the upper spraying disc and the lower spraying disc are adjusted to enable the height difference between the upper spraying disc and the lower spraying disc to range from 40 mm to 60 mm, and the spraying pressure is set to range from 3.5 kg / cm < 3 > to 5.0 kg / cm < 3 >; and S4, cleaning the etched stainless steel material to obtain the bendable resistor. Through the process, the etching uniformity and precision can be improved, and the common problems of non-uniform etching and rough edge in the traditional etching process are effectively avoided. The prepared bendable resistor is high in resistance precision and good in stability, and can meet high requirements of precision electronic equipment on resistance performance and reliability.

Description

Technical Field

[0001] The present application relates to the technical field of electronic resistor manufacturing, and more specifically, to an etching method for a bendable resistor. Background Art

[0002] Bendable resistors usually refer to resistors that have a certain degree of flexibility and bendability and can adapt to certain deformations without affecting their resistance performance. They have broad application prospects in electronic equipment and systems in the fields of flexible electronic devices, space exploration and satellite communications, biomedical equipment, robotics and automation equipment, automobiles, aerospace, and military. In these fields, equipment needs to withstand various complex mechanical stresses and environmental changes, and bendable resistors can provide stable electrical performance and reliable connections.

[0003] Among them, the commonly used bendable resistors are stainless steel bendable resistors. The reason is that stainless steel bendable resistors can usually provide higher resistance accuracy, and the error range is usually within a certain percentage, which can meet the needs of precision electronic equipment. At the same time, its resistance value changes little during use, and has good long-term stability, ensuring the continuous reliability of circuit performance. Stainless steel bendable resistors have high mechanical strength and can withstand certain bending and stretching forces, ensuring the reliability of resistors in long-term use. Stainless steel bendable resistors are durable and have a long life, which can reduce the frequency of replacement and maintenance and reduce maintenance costs.

[0004] The preparation of stainless steel bendable resistors mainly adopts the etching method, which uses the etching method to make the stainless steel surface very smooth and process very fine shapes and patterns. This is crucial for bendable resistors that require precise shapes and tiny details. Through the etching method, the resistance accuracy and stability of the resistor can be ensured to meet the needs of precision electronic equipment. However, the traditional etching process has some limitations, such as uneven etching and rough edges. Among them, improper control of factors such as the concentration, temperature and etching time of the chemical solution will lead to uneven etching. Improper control of the ratio of the etching solution or the etching time will lead to rough edges. This unevenness and rough edge problems will affect the resistance accuracy and stability of the resistor, and then affect the performance and reliability of the resistor.

[0005] In order to solve the above problems, manufacturers use high-temperature etching methods to accelerate chemical reactions by increasing the etching temperature. However, this will lead to a decrease in etching uniformity and accuracy, so improvement is needed. Summary of the invention

[0006] In order to solve the problems of uneven etching, rough edges and high cost in the prior art, the present application provides an etching method for a bendable resistor.

[0007] The present application provides a method for etching a bendable resistor, which adopts the following technical solution: A method for etching a bendable resistor comprises the following preparation steps: S1. Select stainless steel materials, perform high-temperature cleaning on the surface, and use a dyne pen to test whether the stainless steel surface meets the 52# standard; S2, screen printing on both sides of the stainless steel material, performing optical analysis by LDI exposure, developing and molding, and obtaining a stainless steel material with a circuit; S3, spray the etching liquid onto the stainless steel material with the circuit through the upper and lower spray plates for etching, wherein the upper and lower spray plates are adjusted so that the height difference between the upper and lower spray plates is 40-60 mm, and the spray pressure is set to 3.5-5.0 kg / cm 2 , control the temperature within the range of 10-20℃; S4. Clean the etched stainless steel material to obtain a bendable resistor.

[0008] By adopting the above technical solution, the uniformity and precision of etching are improved, and the common problems of uneven etching and rough edges in traditional etching processes are effectively avoided. The prepared bendable resistor has high resistance value precision and good stability, which can meet the high requirements of precision electronic equipment for resistor performance and reliability.

[0009] Among them, the stainless steel surface is treated by high-temperature cleaning and tested with a dyne pen to meet the 52# standard, ensuring the cleanliness and uniformity of the stainless steel surface, providing a good foundation for the subsequent etching process and helping to reduce the problem of uneven etching caused by surface contamination or unevenness. Double-sided silk screen printing and LDI exposure are used for optical analysis and development molding, which can accurately control the shape and size of the circuit pattern, ensure the accuracy and consistency of the circuit pattern during etching, and help avoid problems such as rough edges and shape distortion.

[0010] Adjust the height difference between the upper and lower spray plates (40-60mm), set the spray pressure (3.5-5.0kg / cm 2 ) and control the temperature (within the range of 10-20℃), the contact mode and reaction rate between the etching solution and the surface of the stainless steel material can be accurately controlled, which helps to achieve the uniformity and stability of the etching process and avoids the problems of uneven etching and rough edges caused by improper control of etching solution concentration, temperature or time.

[0011] Preferably, in step S3, oxygen is introduced into the etching solution, and the amount of oxygen added is 0.8-1m 3 / s.

[0012] By adopting the above technical solution, the chemical reaction in the etching solution is increased, thereby increasing the etching rate. At the same time, by controlling the amount of oxygen introduced, the activity of the etching solution can be ensured to remain consistent throughout the etching process, thereby improving the uniformity of etching, optimizing the etching quality, reducing the edge roughness, and making the etched pattern edge smoother. Preferably, a high-precision gas flow meter can be used to deliver oxygen to ensure that the oxygen flow rate is accurately controllable.

[0013] Preferably, in step S3, the etching speed is 2.5-3.5 m / s.

[0014] By adopting the above technical solution, at an appropriate etching speed, the etching liquid can evenly contact and react with the stainless steel surface, thereby ensuring the uniformity of etching, so that the preparation process of the bendable resistor helps to improve the resistance accuracy and stability of the resistor, while reducing production costs and meeting the high requirements of precision electronic equipment for resistor performance.

[0015] Preferably, the etching solution is prepared from the following raw materials in percentage by weight: Ferric chloride 20-40% Hydrochloric acid 4-8% Ammonium persulfate 1-2% Ferrous chloride 1-3% Ethylene glycol ether 4-8% Tartaric acid 1-3% The balance is water.

[0016] By adopting the above technical solution and using an etching solution prepared from raw materials with a specific weight percentage, the etching accuracy and uniformity can be significantly improved, the etching speed and surface quality can be optimized, and the stability and service life of the etching solution can be improved during the preparation process of the bendable resistor. These effects work together in the preparation process of the resistor, which helps to improve the resistance value accuracy and stability of the resistor.

[0017] Among them, ferric chloride, as the main component of the etching solution, has strong oxidizing properties and can undergo redox reactions with metal ions on the surface of stainless steel, thereby achieving an etching effect. At the same time, hydrochloric acid can adjust the pH value of the etching solution and promote the etching reaction. Ammonium persulfate can accelerate the chemical reaction during the etching process, thereby increasing the etching speed. At the same time, ammonium persulfate can also reduce the oxidation reaction between water and silicon in the solution, reduce the generation of hydrogen, and promote the etching reaction to proceed smoothly and evenly. Ferrous chloride has reducing properties and can react with metal ions generated during the etching process to generate corresponding metal chlorides, thereby avoiding the accumulation of metal ions from interfering with the etching process. At the same time, the addition of ferrous chloride can also improve the stability of the etching solution. Ethylene glycol ether and tartaric acid, as additives, can adjust the viscosity and surface tension of the etching solution, thereby improving the fluidity and wettability of the etching solution, and helping the etching solution to better penetrate into the tiny gaps on the surface of stainless steel to achieve a finer etching effect.

[0018] Preferably, the ink used for double-sided screen printing in step S2 is prepared by the following method: 1) Add maleic rosin resin and modified epoxy acrylic resin into a reaction kettle, heat and stir thoroughly, and continue stirring until all of them become liquid; 2) Adding water-based acrylic resin, polyvinyl alcohol, surfactant and distilled water into the above reaction kettle, and continuously stirring at a temperature of 45-55° C. to completely dissolve; 3) placing a wetting agent, a defoaming agent, nano-metal oxide powder and a dispersant into the above reaction kettle and continuously stirring at a temperature of 40-50° C.; 4) After completion, let it stand and finally filter the material to obtain ink.

[0019] By adopting the above technical solution, the prepared ink can improve the adhesion of the ink during the double-sided screen printing process, and the maleic rosin resin and modified epoxy acrylic resin can improve the adhesion of the ink, ensuring that the ink is not easy to fall off during the etching process, so as to facilitate subsequent etching. The addition of water-based acrylic resin and polyvinyl alcohol can adjust the fluidity and viscosity of the ink, so that the ink can be evenly and smoothly coated on the stainless steel surface during the double-sided screen printing process, which helps to achieve a finer and clearer pattern printing effect and improve the resistance value accuracy and stability of the resistor.

[0020] The addition of surfactants and dispersants can significantly improve the dispersibility and stability of nano-metal oxide powders in inks. They can reduce the surface tension of the ink, promote the uniform dispersion of nano-metal oxide powders in the ink, and prevent particle agglomeration and precipitation. This helps ensure that the ink can corrode the stainless steel surface evenly and consistently during the etching process, achieving a finer etching effect. The addition of wetting agents can improve the wettability of the ink on the stainless steel surface, making it easier to apply the ink on the surface. The addition of defoamers can prevent the ink from generating bubbles during the printing process, which affects the printing effect.

[0021] Preferably, the weight parts of the raw materials used to prepare the ink are as follows: 3-5 parts of maleic rosin resin Modified epoxy acrylic resin 1-2 parts 5-10 parts of water-based acrylic resin Polyvinyl alcohol 5-10 parts 1-2 parts surfactant 25-30 parts of distilled water 3-5 parts of wetting agent 1-2 parts of defoamer 4-8 parts of nano-metal oxide powder Dispersant 2-3 parts.

[0022] By adopting the above technical solution, the amount of ink used in the preparation is optimized so that the ink has suitable viscosity and fluidity, which is beneficial to improving the adhesion of the ink and ensuring that the ink is not easy to fall off during the etching process, so as to facilitate subsequent etching.

[0023] Preferably, the modified epoxy acrylic resin has a fluid viscosity of 15000-25000 mPa.s at 25° C. and an acid value of less than 3 mgKOH / g.

[0024] By adopting the above technical solution, the fluid viscosity range of the modified epoxy acrylic resin at 25°C is moderate, neither too viscous nor too thin, which enables the ink to be evenly and smoothly coated on the stainless steel surface during the double-sided silk screen printing process, helping to achieve finer and clearer pattern printing effects and improve the resistance value accuracy and stability of the resistor.

[0025] Preferably, the maleic rosin resin has an acid value of 16-220 mgKOH / g and a softening point of 108-170°C.

[0026] By adopting the above technical solution, the acid value and softening point of maleic acid rosin are optimized, the fluidity and transferability of the ink are further improved, and the clarity and uniformity of the printed matter are ensured.

[0027] Preferably, the high temperature cleaning process in step S1 is as follows: Mix 40-50 g / L sulfuric acid, 80-100 g / L citric acid, 30-40 g / L aminosulfonic acid, 100-120 g / L nano silicon dioxide, 40-50 g / L polyethylene glycol, 5-15 g / L hydrogen peroxide and 4-5 g / L dodecylpyridine to obtain a cleaning solution; Heat the stainless steel material to 100-120℃, then immerse the stainless steel material in the cleaning solution, ultrasonicate for 1-2h, the ultrasonic frequency is 50-60kHz, the power is 500-600W, then rinse with clean water and dry.

[0028] By adopting the above technical solution, the surface of the stainless steel material after high-temperature cleaning is smoother and cleaner, which helps the subsequent etching process to proceed more smoothly. Heating the stainless steel material to 100-120℃ increases the temperature of the material surface, makes the chemical components in the cleaning solution more active, accelerates the chemical reaction and physical action, and thus enhances the cleaning effect. Ultrasonic waves of 1-2h, 50-60kHz frequency, and 500-600W power can produce strong vibration and cavitation effects, which can penetrate the tiny gaps on the surface of stainless steel, shake out the stains hidden therein and disperse them into the cleaning solution.

[0029] In summary, this application has the following beneficial effects: 1. In this application, the bendable resistor prepared through the steps of high-temperature cleaning - double-sided silk screen printing - LDI exposure for optical analysis - low-temperature spray etching solution has a smoother surface, finer shape and pattern, and significantly improved resistance accuracy and stability. It effectively solves the problems of uneven etching and rough edges in traditional etching processes, thereby improving the performance and reliability of the resistor. DETAILED DESCRIPTION

[0030] Maleic acid rosin resins were purchased from Fengyi Rosin Factory, Guiping City, Guangxi.

[0031] Modified epoxy acrylic resins were purchased from Shandong Shoucheng Chemical Co., Ltd.

[0032] The water-based acrylic resin was purchased from Shandong Kepler Biotechnology Co., Ltd., model number is kpl-63666.

[0033] Preparation Example Preparation Example 1 An ink for double-sided printing is prepared by the following method: 1) Add 30g of maleic rosin resin and 10g of modified epoxy acrylic resin into a reaction kettle, heat and stir thoroughly, and continue stirring until all of them become liquid; 2) 50 g of water-based acrylic resin, 50 g of polyvinyl alcohol, 10 g of surfactant (cocoyl glucoside) and 250 g of distilled water were added to the above reaction kettle and stirred continuously at 45° C. until all the mixture was dissolved; 3) 30 g of wetting agent (sodium stearate), 10 g of defoaming agent (lauric acid) and 40 g of nano-metal oxide powder (iron oxide) were placed in the above reaction kettle and stirred continuously at a temperature of 40° C.; 4) After completion, let it stand and finally filter the material to obtain ink.

[0034] The fluid viscosity of the modified epoxy acrylic resin at 25° C. is 15000-25000 mPa.s, and the acid value is less than 3 mgKOH / g.

[0035] The acid value of maleic acid rosin resin is 16 mgKOH / g and the softening point is 108°C.

[0036] The difference between Preparation Example 2-3 and Preparation Example 1 is that the types and amounts of ink raw materials used in the preparation of double-sided printing and the experimental parameters are different. The specific differences are shown in Table 1: Table 1 Types, amounts and experimental parameters of ink raw materials used in preparation of double-sided printing in Preparation Examples 1-3 Preparation Example 4 An ink for double-sided printing, the difference between this preparation example and preparation example 1 is that the nano metal oxide powder is obtained by mixing iron oxide, magnesium oxide and aluminum oxide in a weight ratio of 5:1:3.

[0037] Preparation Example 5 An ink for double-sided printing, the difference between this preparation example and preparation example 1 is that the nano metal oxide powder is obtained by mixing iron oxide, magnesium oxide and aluminum oxide in a weight ratio of 5:3:3.

[0038] Preparation Example 6 An etching solution is prepared by the following method: Ferric chloride, hydrochloric acid, ammonium persulfate, ferrous chloride, ethylene glycol ethyl ether, tartaric acid and water are uniformly mixed to obtain an etching solution.

[0039] The difference between Preparation Example 7-8 and Preparation Example 6 is that the types and amounts of raw materials used to prepare the etching solution and the experimental parameters are different. The specific differences are shown in Table 2: Table 2 Types, amounts and experimental parameters of ink raw materials used in double-sided printing in Preparation Examples 6-8 Experimental raw material types, dosage and experimental parameters Preparation Example 6 Preparation Example 7 Preparation Example 8 Ferrous chloride (g) 200 300 400 Hydrochloric acid(g) 40 60 80 Ammonium persulfate(g) 10 11 12 Ferrous chloride(g) 10 20 30 Ethylene glycol ether(g) 40 60 80 Tartaric acid(g) 10 20 30 Water(g) 690 529 368 Preparation Comparative Example Preparation Comparative Example 1 A double-sided printing ink is used. The difference between this comparative preparation example and preparation example 1 is that rosin resin is used instead of maleic acid rosin resin.

[0040] Hydrogenated rosin resin was purchased from Henan Dazheng Chemical Products Co., Ltd. with a brand number of 138.

[0041] Preparation Comparative Example 2 A double-sided printing ink is used. The difference between this comparative preparation example and preparation example 1 is that epoxy resin is used instead of modified epoxy acrylic resin.

[0042] The epoxy resin was purchased from Henan Huineng Resin Co., Ltd., model E-51.

[0043] Preparation Comparative Example 3 A double-sided printing ink is used. The difference between this comparative preparation example and preparation example 1 is that silicon dioxide is used instead of nano-metal oxide powder. Example

[0044] Example 1 A method for etching a bendable resistor is prepared by the following method: S1. Select stainless steel material with a thickness of 0.2mm, perform high-temperature cleaning on the surface, and use a dyne pen to test whether the stainless steel surface meets the 52# standard; S2, performing double-sided screen printing on the stainless steel material, using the ink prepared in Preparation Example 1 for printing, performing optical analysis by LDI exposure, and developing and molding to obtain a stainless steel material with a circuit; S3, the etching solution in Preparation Example 6 is sprayed onto the stainless steel material with the circuit through the upper and lower spray plates for etching, wherein the upper spray pipe rack height is adjusted to 60 mm, the lower spray pipe rack height is adjusted to 100 mm, the direct spray height of the solution is maintained, and the spray pressure is set to 3.5 kg / cm 2 , control the temperature at 10°C, set the etching time to 15 minutes, and the etching speed to 2.5m / s; S4. Clean the etched stainless steel material to obtain a bendable resistor.

[0045] The high temperature cleaning process in step S1 is as follows: Mix 40 g / L sulfuric acid, 80 g / L citric acid, 30 g / L aminosulfonic acid, 100 g / L nano silicon dioxide, 40 g / L polyethylene glycol, 5 g / L hydrogen peroxide and 1 g / L dodecylpyridine to obtain a cleaning solution; Heat the stainless steel material to 100-120℃, then immerse the stainless steel material in the cleaning solution, ultrasonicate for 1-2h, the ultrasonic frequency is 50-60kHz, the power is 500-600W, then rinse with clean water and dry.

[0046] The difference between Example 2-3 and Example 1 is that the types and amounts of raw materials used to prepare the bendable resistor and the experimental parameters are different. The specific differences are shown in Table 2: Table 3 Types, amounts and experimental parameters of materials for preparing bendable resistors in Example 1-3 Example 4 A method for etching a bendable resistor. The difference between this embodiment and embodiment 1 is that the ink comes from preparation example 4.

[0047] Example 5 A method for etching a bendable resistor. The difference between this embodiment and embodiment 1 is that the ink comes from preparation example 5.

[0048] Example 6 A method for etching a bendable resistor. The difference between this embodiment and embodiment 1 is that in step S3, a high-precision gas flow meter is used to introduce oxygen into the etching solution, and the increase in oxygen is 0.8m 3 / s.

[0049] Example 7 A method for etching a bendable resistor. The difference between this embodiment and embodiment 1 is that: in step S3, a high-precision gas flow meter is used to introduce oxygen into the etching solution, and the increase in oxygen is 1m 3 / s.

[0050] Comparative Example Comparative Example 1 A method for etching a bendable resistor. The difference between this comparative example and Example 1 is that in step S1, the stainless steel material is directly placed in a cleaning solution for cleaning.

[0051] Comparative Example 2 A method for etching a bendable resistor. The difference between this comparative example and Example 1 is that the temperature in step S3 is controlled at 30°C.

[0052] Comparative Example 3 A method for etching a bendable resistor. The difference between this comparative example and Example 1 is that the injection pressure in step S3 is 2 kg / cm 2 .

[0053] Comparative Example 4 A method for etching a bendable resistor. The difference between this comparative example and Example 1 is that in step S1, the stainless steel material is directly placed in pure water for cleaning.

[0054] Detection method / test method Observe whether there are burrs or burrs: Use a 40x magnifying glass to observe the bendable resistors prepared in Examples 1-7 and Comparative Examples 1-3 to observe whether there are burrs or burrs at the etched areas.

[0055] Smoothness: The smoothness of the vertical and cross sections was tested by a roughness tester. The bendable resistors prepared in Examples 1-7 and Comparative Examples 1-3 were tested.

[0056] Resistance test: Randomly select 4 areas of the bendable resistors prepared in Examples 1-7 and Comparative Examples 1-3, use a resistance tester to measure the resistance of each area, and record whether the maximum resistance value measured in different areas of the same material is only 0.0002Ω. The experimental data is shown in Table 4: Table 4 Experimental data of Examples 1-7 and Comparative Examples 1-3 Examples or Comparative Examples Are there any burrs or burrs? Finish Resistance test Example 1 none 1.8 0.0002 Example 2 none 1.8 0.00019 Example 3 none 1.8 0.00018 Example 4 none 1.8 0.00011 Example 5 none 1.8 0.00012 Example 6 none 1.8 0.00015 Example 7 none 1.8 0.00016 Comparative Example 1 With rough edges 2.4 yes Comparative Example 2 There are burrs 1.8 yes Comparative Example 3 There are burrs 1.8 yes Comparative Example 4 With rough edges 2.8 yes By comparing Example 1 with Comparative Examples 1-4, Comparative Examples 1-4 showed burrs and burrs when observing whether there were burrs or burrs; the value of Comparative Example 1 in the smoothness test was 2.4; the resistance errors of Comparative Examples 1-4 in the resistance test were all greater than 0.0002Ω, indicating that the bendable resistors prepared by the process in the present application can effectively improve the uniformity and accuracy of etching, and reduce the problems of uneven etching and rough edges.

[0057] Comparing Example 1 with Examples 4-5, the resistance error values ​​of Examples 4-5 in the resistance test are all smaller than those of Example 1, indicating that the uniformity and accuracy of etching can be effectively improved by using iron oxide, magnesium oxide and aluminum oxide in a specific weight ratio.

[0058] Comparing Example 1 with Examples 6-7, the resistance error values ​​of Examples 6-7 in the resistance test are all smaller than that of Example 1, indicating that adding an appropriate amount of oxygen is beneficial to improving the uniformity and accuracy of etching.

[0059] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed. However, as long as it is within the scope of the claims of the present application, it shall be protected by the patent law.

Claims

1. A method for etching a bendable resistor, characterized in that: The method comprises the following preparation steps: S1. Select stainless steel material, perform high temperature cleaning on the surface, and use a dyne pen to test whether the stainless steel surface meets the 52# standard; S2, screen printing on both sides of the stainless steel material, performing optical analysis by LDI exposure, developing and molding, and obtaining a stainless steel material with a circuit; S3, spraying the etching liquid onto the stainless steel material with the circuit through the upper and lower spray plates for etching, wherein the upper and lower spray plates are adjusted so that the height difference between the upper and lower spray plates is 40-60mm, the spray pressure is set to 3.5-5.0kg / cm², and the temperature is controlled within the range of 10-20℃; S4. Clean the etched stainless steel material to obtain a bendable resistor.

2. The etching method of the bendable resistor according to claim 1, characterized in that: In step S3, oxygen is introduced into the etching solution, and the amount of oxygen added is 0.8-1m 3 / s.

3. The etching method of the bendable resistor according to claim 2, characterized in that: In step S3, the etching speed is 2.5-3.5 m / s.

4. The etching method of a bendable resistor according to claim 1, characterized in that: The high temperature cleaning process in step S1 is as follows: Mix 40-50 g / L sulfuric acid, 80-100 g / L citric acid, 30-40 g / L aminosulfonic acid, 100-120 g / L nano silicon dioxide, 40-50 g / L polyethylene glycol, 5-15 g / L hydrogen peroxide and 4-5 g / L dodecylpyridine to obtain a cleaning solution; Heat the stainless steel material to 100-120℃, then immerse the stainless steel material in the cleaning solution, ultrasonicate for 1-2h, the ultrasonic frequency is 50-60kHz, the power is 500-600W, then rinse with clean water and dry.

5. The etching method of the bendable resistor according to claim 4, characterized in that: The ink used for double-sided screen printing in step S2 is prepared by the following method: 1) Add maleic rosin resin and modified epoxy acrylic resin into the reaction kettle, heat and stir thoroughly, and continue stirring until all become liquid; 2) Add water-based acrylic resin, polyvinyl alcohol, surfactant and distilled water into the above reaction kettle, and continue stirring at a temperature of 45-55°C until all of them are dissolved; 3) Place the wetting agent, defoaming agent and nano-metal oxide powder into the above reaction kettle and continue stirring at a temperature of 40-50°C; 4) After completion, let it stand and finally filter the material to obtain the ink.

6. The etching method of the bendable resistor according to claim 4, characterized in that: The weight parts of the raw materials used to prepare the ink are as follows: 3-5 parts of maleic rosin resin Modified epoxy acrylic resin 1-2 parts 5-10 parts of water-based acrylic resin Polyvinyl alcohol 5-10 parts 1-2 parts surfactant 25-30 parts of distilled water 3-5 parts of wetting agent 1-2 parts of defoamer 4-8 parts of nano metal oxide powder.

7. The etching method of a bendable resistor according to claim 1, characterized in that: The modified epoxy acrylic resin has a fluid viscosity of 15000-25000 mPa.s at 25° C. and an acid value of less than 3 mgKOH / g.

8. The etching method of a bendable resistor according to claim 1, characterized in that: The maleic rosin resin has an acid value of 16-220 mgKOH / g and a softening point of 108-170°C.

9. The etching method of a bendable resistor according to claim 1, characterized in that: The nano-metal oxide powder is obtained by mixing iron oxide, magnesium oxide and aluminum oxide in a weight ratio of 5: (1-3):

3.

10. The etching method of a bendable resistor according to claim 1, characterized in that: The etching solution is prepared from the following raw materials in weight percentage: Ferric chloride 20-40% Hydrochloric acid 4-8% Ammonium persulfate 1-2% Ferrous chloride 1-3% Ethylene glycol ether 4-8% Tartaric acid 1-3% The balance is water.

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