Anti-sulfuration and salt spray resistant membrane switch and manufacturing method thereof

Abstract

The invention provides an anti-vulcanization and salt spray resistant membrane switch and a manufacturing method thereof, the switch comprises an upper membrane and a lower membrane, an upper interlayer and a lower interlayer are respectively arranged below the upper membrane and above the lower membrane, and the upper interlayer and the lower interlayer are bonded together through a pressure-sensitive glue layer; through holes are formed in the upper interlayer, the pressure-sensitive glue layer and the lower interlayer, and a pressing air cavity is defined by the hole walls of the through holes, the lower surface of the upper membrane and the upper surface of the lower membrane; the pressure-sensitive glue layer is provided with an exhaust channel communicated with the pressing air cavity, and a waterproof breathable film is embedded in an opening, communicated with the outside, of the exhaust channel. Lines on the upper diaphragm and the lower diaphragm are protected through the upper diaphragm and the lower diaphragm, the vulcanization resistance and the salt spray resistance of the lines are improved, the waterproof breathable film used for preventing water vapor from flowing is arranged in the exhaust channel, water vapor is prevented from entering the pressing air cavity through the exhaust channel, oxidation and corrosion of contacts and the lines are prevented, and the service life of the circuit is prolonged. Air inlet and outlet of the pressing air cavity cannot be affected, and the pressing comfort is good.

Description

Technical Field

[0001] The present invention relates to the technical field of membrane switches, and in particular to a membrane switch that is anti-sulfurization and salt spray resistant and a manufacturing method thereof. Background Art

[0002] Membrane switches are an integrated operating system that integrates key functions, indicator elements, and instrument panels. Existing membrane switches have a three-layer structure: upper and lower conductive layers, with an isolation layer in the middle. The isolation layer is bonded to the upper and lower layers using screen-printed pressure-sensitive adhesive. Membrane switches require an internal airway to communicate with the outside world. The wiring where this airway passes is exposed, preventing it from being completely sealed and exposing it to air, creating the risk of corrosion from sulfide and salt spray.

[0003] A Chinese patent document (publication number CN116504563A) discloses a novel waterproof, oxidation-resistant, and sulfur-resistant membrane switch and its manufacturing method. The switch seals the circuitry with a protective layer, then prints pressure-sensitive adhesive directly onto the protective layer, preventing contact with the circuitry and thus preventing interference. Furthermore, an air escape duct is designed through the pressure-sensitive adhesive to connect to the outside world. While this approach can protect the circuitry through the protective layer, it suffers from the following drawbacks: 1. The air escape duct is directly connected to the outside world, making it difficult to block moisture, sulfur-containing gases, and salt spray from the environment. These moisture, sulfur-containing gases, and salt spray can enter and react with the silver paste in the press-type air cavity, affecting the conductivity and lifespan of the membrane switch. 2. The air escape duct is pre-placed on the pressure-sensitive adhesive, making it difficult to maintain its shape during the lamination of the upper and lower layers. It easily closes before curing, preventing air from entering or exiting the pressure chamber and resulting in a poor press feel. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the object of the present invention is to provide a membrane switch that is resistant to sulfurization and salt spray, which is used to solve the problem in the prior art that directly reserving an escape channel on the pressure-sensitive adhesive will cause water vapor, sulfur-containing gas and salt spray to enter the pressing air cavity, affecting the conductivity and life of the membrane switch, and the escape channel is easily closed during the pressing process, resulting in failure. At the same time, the present invention will also provide a method for manufacturing the membrane switch that is resistant to sulfurization and salt spray.

[0005] To achieve the above-mentioned and other related purposes, the present invention provides the following technical solutions: According to a first aspect of the present invention, a sulfide-resistant and salt-spray-resistant membrane switch is provided, comprising an upper membrane and a lower membrane, wherein the lower surface of the upper membrane and the upper surface of the lower membrane are both printed with a circuit formed by a conductive paste, and a plurality of contacts are provided on the circuit. An upper partition layer and a lower partition layer for protecting the circuit are respectively provided below the upper membrane and above the lower membrane, and the upper partition layer and the lower partition layer are bonded together by a pressure-sensitive adhesive layer. Through holes are provided in the upper partition layer, the pressure-sensitive adhesive layer and the lower layer, and a pressing air cavity is formed between the hole wall of the through hole, the lower surface of the upper membrane and the upper surface of the lower membrane, and the contacts are located in the pressing air cavity. An exhaust channel connected to the pressing air cavity is provided on the pressure-sensitive adhesive layer, and a waterproof breathable membrane is embedded in the opening of the exhaust channel connected to the outside world.

[0006] The upper and lower interlayers of the present invention can comprehensively and stably protect the circuits on the upper and lower diaphragms. On the one hand, they seal the circuits, preventing them from being exposed to the outside world, thereby improving their anti-sulfurization and salt spray resistance. On the other hand, the upper and lower interlayers can be directly bonded to each other, providing structural protection for the circuits on the diaphragms and preventing the effects of pressure-sensitive adhesive printing and baking on the circuits. Furthermore, by providing a waterproof and breathable membrane within the exhaust channel to block the flow of water vapor, water vapor is prevented from entering the pressing cavity through the exhaust channel, preventing oxidation and corrosion of the contacts and circuits without affecting the air in and out of the pressing cavity, resulting in a comfortable pressing experience.

[0007] As a preferred technical solution, the exhaust channel includes a main airway and an auxiliary airway. The first end of the main airway communicates with the outside world, and the second end of the main airway communicates with the compression air cavity through the auxiliary airway. The cross-sectional area of ​​the main airway is larger than that of the auxiliary airway. The provision of the main and auxiliary airways can extend the path for sulfur-containing gases, salt spray, and other gases to enter the compression air cavity, thereby reducing damage to the circuit and contacts caused by such gases.

[0008] As a preferred technical solution, the cross-sectional area of ​​the main air channel gradually increases from the second end to the first end, and the waterproof breathable membrane is embedded in the first end opening of the main air channel.

[0009] On the one hand, due to the fluid effect, the cross-sectional area of ​​the main airway gradually increases from the second end to the first end, which can gradually reduce the gas flow rate from the second end to the first end, ensuring that the gas enters and exits the waterproof breathable membrane slowly, allowing the waterproof breathable membrane to more effectively isolate water vapor, etc. On the other hand, the waterproof breathable membrane is easily clogged by salt crystals due to long-term gas exchange. By changing the cross-sectional area of ​​the main airway, the present invention creates an asymmetrical structure for the waterproof breathable membrane embedded at the end, making it easier for the airflow to blow out the salt crystals.

[0010] As a preferred technical solution, a special screen is used to make the cross-section of the exhaust channel after printing into an inverted trapezoid, which can prevent it from being completely closed during subsequent pressing and ensure the smooth flow of the exhaust channel.

[0011] As a preferred technical solution, the pressure-sensitive adhesive layer includes a first adhesive layer and a second adhesive layer, the second adhesive layer is arranged around the outer edge of the first adhesive layer, the pressing air cavity and the exhaust channel are in direct contact with the second adhesive layer, and under the same conditions, the fluidity of the second adhesive layer is less than the fluidity of the first adhesive layer.

[0012] In order to ensure the connection strength between the upper and lower partitions, the first adhesive layer usually has high viscosity and fluidity. In order to prevent the first adhesive layer from flowing before solidification and causing the exhaust channel to close, a second adhesive layer is set at the outer edge of the first adhesive layer. The second adhesive layer has low fluidity and can provide a certain support effect. It acts as a "fence" to limit the lateral flow of the first adhesive layer, better maintain the shape of the exhaust channel, and avoid clogging the exhaust channel.

[0013] Furthermore, the second adhesive layer includes a base resin, a tackifying resin, a solvent, and a filler, wherein the filler content in the second adhesive layer is higher than the filler content in the first adhesive layer; or the first adhesive layer contains no filler. The addition of the filler can thicken the pressure-sensitive adhesive, reduce its fluidity, and provide a certain degree of support.

[0014] Furthermore, the filler includes at least one of hydrophobically modified silica, nano-calcium carbonate, and nano-alumina.

[0015] Due to its high specific surface area, silica can adsorb free sulfur molecules and prolong the Cl - The hydrophobically modified silica not only inhibits the fluidity of the second adhesive layer, but also maintains the viscosity of the second adhesive layer. Nano-calcium carbonate can reduce the fluidity of the material through the particle accumulation effect and can absorb acidic sulfides (such as H2S) and Cl - Nano-alumina can effectively inhibit the fluidity of glue, forming nano-scale grains or non-crystalline substances inside the resin, reducing the material's water absorption and inhibiting electrochemical corrosion.

[0016] By selecting this type of filler, the waterproof, anti-sulfurization and salt spray resistance of the second adhesive layer can also be improved. By surrounding it at the outer edge of the first adhesive layer, the second adhesive layer can directly contact the exhaust channel and the outer edge of the membrane switch, thereby improving the overall waterproof, anti-sulfurization and salt spray resistance of the membrane switch.

[0017] Furthermore, the second adhesive layer includes the following components in parts by mass: 50-70 parts of base resin, 10-30 parts of tackifying resin, 5-25 parts of solvent, 10-25 parts of filler, 1-6 parts of toughening agent, and 0.5-3 parts of cross-linking agent.

[0018] Furthermore, the first adhesive layer may be made of conventional pressure-sensitive adhesive or the amount of filler used may be reduced or no filler may be added in the formulation of the second adhesive layer.

[0019] As a preferred technical solution, the outer surface of the contact is covered with an isolation layer, and the isolation layer is formed by sintering conductive carbon paste or silver-palladium alloy paste.

[0020] Conductive carbon paste is extremely chemically inert, does not react with elemental sulfur, and is completely resistant to sulfidation. It also avoids electrochemical corrosion and effectively prevents sulfidation and salt spray. Silver-palladium alloy is more conductive than conductive carbon paste. Palladium inhibits silver sulfidation, significantly improving sulfidation resistance. Palladium is also resistant to chloride ion corrosion, protecting the silver matrix and resisting salt spray corrosion.

[0021] As a preferred technical solution, the upper and lower layers are made of fully adhesive film. They include a film layer and an adhesive layer. Before assembly, the adhesive layers are protected with release film. The upper and lower layers are attached to the circuitry of the upper and lower diaphragms, respectively, via the adhesive layers. The upper and lower layers are also pre-reserved with through-holes for forming pressure cavities and other regular or irregularly shaped holes for positioning or special functions.

[0022] Furthermore, the film layer is made of PET film or PI film.

[0023] A second aspect of the present invention provides a method for manufacturing a membrane switch that is resistant to sulfidation and salt spray, comprising the following steps: S1. After the upper and lower diaphragms are made with circuits and contacts, they are rolled into a roll and the required holes are punched in advance. S2. Die-cut the upper and lower interlayers with release film, fully cut the through holes and other structural holes, and half cut the outer edges; fully cut means the substrate and release film are cut off, half cut means the substrate is cut off but the release film is not, and the release film is used as a carrier tape to form a roll; S3, positioning and laminating the upper film and the upper spacer, positioning and laminating the lower film and the lower spacer, and separating the release film after lamination; S4. Silk-screening pressure-sensitive adhesive on the upper or lower interlayer, with the silk-screen shape of the pressure-sensitive adhesive reserving an exhaust channel connected to each through hole; S5. The upper and lower partitions are bonded together with pressure-sensitive adhesive. After the lamination is completed, a waterproof and breathable membrane is filled in the end opening of the exhaust channel to obtain a membrane switch that is anti-sulfurization and salt spray resistant.

[0024] As a preferred technical solution, in step S4, the second adhesive layer is firstly screen-printed on the upper spacer or the lower spacer, and then the first adhesive layer is screen-printed after the second adhesive layer is semi-cured.

[0025] As described above, the anti-sulfurization and salt spray resistant membrane switch and its manufacturing method of the present invention have the following beneficial effects: 1. The present invention protects the circuits on the upper and lower diaphragms by means of upper and lower partitions, thereby improving the anti-sulfurization and salt spray resistance of the circuits. In addition, a waterproof and breathable membrane is provided in the exhaust channel to block the flow of water vapor, thereby preventing water vapor from entering the pressing air cavity through the exhaust channel, thereby preventing oxidation and corrosion of the contacts and circuits, and also not affecting the air inlet and outlet of the pressing air cavity, thereby providing good pressing comfort.

[0026] 2. On the one hand, the present invention controls the cross-section of the exhaust channel to be an inverted trapezoid, which can prevent it from being completely closed during subsequent pressing, thereby ensuring the smooth flow of the exhaust channel; on the other hand, the present invention provides a second adhesive layer with lower fluidity on the outer edge of the first adhesive layer, so that the second adhesive layer provides a certain support effect and acts as a "fence" to limit the lateral flow of the first adhesive layer, thereby better maintaining the shape of the exhaust channel and avoiding blockage of the exhaust channel.

[0027] 3. The present invention adjusts the fluidity of the second adhesive layer by fillers, and selects hydrophobically modified silica, nano-calcium carbonate, and nano-alumina with better anti-sulfurization and salt spray resistance as fillers to improve the waterproof, anti-sulfurization and salt spray resistance of the exhaust channel.

[0028] 4. By setting the main airway and the auxiliary airway and controlling the cross-sectional area of ​​the main airway to gradually increase from the second end to the first end, the gas flow rate can be gradually reduced from the second end to the first end, ensuring that the gas slowly enters and exits the waterproof breathable membrane, so that the waterproof breathable membrane can more fully isolate water vapor, etc.; it can also make the waterproof breathable membrane embedded at the end have an asymmetrical structure up and down, which can make it easier for salt crystals to be blown out by the airflow. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic top view of the anti-sulfurization and salt spray resistant membrane switch disclosed in Example 2 of the present invention.

[0030] Figure 2 This is a schematic cross-sectional view of the anti-sulfurization and salt spray resistant membrane switch disclosed in Example 2 of the present invention.

[0031] Figure 3 This is a schematic cross-sectional view of the pressure-sensitive adhesive layer disclosed in Example 2 of the present invention.

[0032] Component number description: 100, upper diaphragm; 200, lower diaphragm; 300, contact; 310, isolation layer; 400, upper partition; 500, lower partition; 600, pressure-sensitive adhesive layer; 610, first adhesive layer; 620, second adhesive layer; 700, press air cavity; 800, exhaust channel; 810, main air duct; 820, auxiliary air duct; 900, waterproof and breathable membrane. DETAILED DESCRIPTION

[0033] The following describes the implementation of the present invention through specific embodiments. People skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0034] Example 1 This embodiment provides a sulfide-resistant and salt-spray-resistant membrane switch, comprising an upper diaphragm 100 and a lower diaphragm 200. Circuits formed of a conductive paste are printed on the lower surface of the upper diaphragm and the upper surface of the lower diaphragm. A plurality of contacts 300 are provided on the circuits. An upper partition layer 400 and a lower partition layer 500 for protecting the circuits are provided below the upper diaphragm and above the lower diaphragm, respectively. The upper and lower partition layers are bonded together by a pressure-sensitive adhesive layer 600. Through holes extending in the vertical direction are provided on the upper partition layer, the pressure-sensitive adhesive layer, and the lower layer. A pressing air cavity 700 is formed between the hole walls of the through hole, the lower surface of the upper diaphragm, and the upper surface of the lower diaphragm. The contacts are located within the pressing air cavity. An exhaust channel 800 communicating with the pressing air cavity is provided on the pressure-sensitive adhesive layer.

[0035] The exhaust channel includes a main air channel 810 and an auxiliary air channel 820. The first end of the main air channel is connected to the outside world, and the second end of the main air channel is connected to the pressing air cavity through the auxiliary air channel; the cross-sectional area of ​​the main air channel is larger than the cross-sectional area of ​​the auxiliary air channel; a waterproof and breathable membrane 900 is embedded in the opening of the first end of the main air channel, and the waterproof and breathable membrane is in a columnar shape that is consistent from top to bottom and is tightened in the opening.

[0036] Example 2 refer to Figures 1 and 2This embodiment provides a membrane switch that is sulfide-resistant and salt-spray-resistant, comprising an upper membrane 100 and a lower membrane 200. Circuits formed of a conductive paste are printed on the lower surface of the upper membrane and the upper surface of the lower membrane. Several contacts 300 are provided on the circuits. An upper partition layer 400 and a lower partition layer 500 for protecting the circuits are provided below the upper membrane and above the lower membrane, respectively. The upper and lower partition layers are bonded together by a pressure-sensitive adhesive layer 600. A through hole is provided in the upper partition layer, the pressure-sensitive adhesive layer, and the lower layer, extending vertically. A pressing air cavity 700 is formed between the hole wall, the lower surface of the upper membrane, and the upper surface of the lower membrane. The contacts are located in the pressing air cavity, and an exhaust channel 800 communicating with the pressing air cavity is provided on the pressure-sensitive adhesive layer.

[0037] refer to Figure 1 The exhaust channel includes a primary air channel 810 and an auxiliary air channel 820. The first end of the primary air channel communicates with the outside world, while the second end of the primary air channel communicates with the compression air chamber via the auxiliary air channel. The cross-sectional area of ​​the primary air channel is larger than that of the auxiliary air channel, and the cross-sectional area of ​​the primary air channel gradually increases from the second end to the first end. A waterproof, breathable membrane 900 is embedded in the opening at the first end of the main air channel. The membrane is in the shape of a trapezoidal column and is tensioned within the opening.

[0038] refer to Figures 1-3 The pressure-sensitive adhesive layer includes a first adhesive layer 610 and a second adhesive layer 620. The second adhesive layer is arranged around the outer edge of the first adhesive layer. The pressing air cavity and the exhaust channel are in direct contact with the second adhesive layer. Under the same conditions, the fluidity of the second adhesive layer is less than that of the first adhesive layer.

[0039] The outer surface of the contact is covered with an isolation layer 310, which is formed by sintering conductive carbon paste or silver-palladium alloy paste.

[0040] The upper and lower layers are made of fully adhesive film, comprising a film layer and an adhesive layer. Before assembly, the adhesive layers are protected with release film. The upper and lower layers are attached to the circuitry of the upper and lower diaphragms, respectively, via the adhesive layers. They also have through-holes reserved for forming pressure cavities, as well as other regular or irregularly shaped holes for positioning or special functions.

[0041] This embodiment also provides a method for manufacturing the anti-sulfurization and salt spray resistant membrane switch, comprising the following steps: S1. After the upper and lower diaphragms are made with circuits and contacts, they are rolled into a roll and the required holes are punched in advance. S2. Die-cut the upper and lower interlayers with release film, fully cut the through holes and other structural holes, and half cut the outer edges; fully cut means the substrate and release film are cut off, half cut means the substrate is cut off but the release film is not, and the release film is used as a carrier tape to form a roll; S3, positioning and laminating the upper film and the upper spacer, positioning and laminating the lower film and the lower spacer, and separating the release film after lamination; S4. Silk-screen a second adhesive layer on the upper or lower spacer. The silk-screen shape of the second adhesive layer reserves an exhaust channel. After the second adhesive layer is semi-cured, silk-screen the first adhesive layer on the inner side thereof. S5. The upper and lower partitions are bonded together with pressure-sensitive adhesive. After the lamination is completed, a waterproof and breathable membrane is filled in the end opening of the exhaust channel to obtain a membrane switch that is anti-sulfurization and salt spray resistant.

[0042] Example 3 This embodiment provides a membrane switch that is anti-sulfurization and salt spray resistant. Compared with Example 2, the only difference is that when printing the second adhesive layer, the side edge of the second adhesive layer that contacts the exhaust channel is controlled to be an inclined surface, so that the cross-section of the exhaust channel is an inverted trapezoid.

[0043] Example 4 This embodiment provides a membrane switch that is sulfide-resistant and salt-spray-resistant. Compared with Example 2, the only difference is that the first adhesive layer uses a commercially available pressure-sensitive adhesive formula, while the second adhesive layer uses a special formula of the present invention, comprising the following components by weight: 60 parts of acrylate, 15 parts of hydrogenated C9 petroleum resin, 5 parts of cyclohexanone, 20 parts of hydrophobic silica, 3 parts of epoxy soybean oil toughening agent, and 1 part of aziridine crosslinking agent.

[0044] Example 5 This embodiment provides a membrane switch that is sulfide-resistant and salt-spray-resistant. Compared with Example 4, the only difference is that the first adhesive layer adopts a special formula of the present invention, comprising the following components by weight: 70 parts of acrylate, 20 parts of C5 petroleum resin, 10 parts of acetone, 5 parts of dibutyl phthalate toughening agent, and 1 part of isocyanate crosslinking agent.

[0045] The solvent of the first adhesive layer is acetone, and the solvent of the second adhesive layer is cyclohexanone, which can prevent the first adhesive layer and the second adhesive layer from dissolving each other.

[0046] Example 6 This embodiment provides a membrane switch that is sulfide-resistant and salt-spray-resistant. Compared with Example 2, the only difference is that the first adhesive layer uses a commercially available pressure-sensitive adhesive formula, while the second adhesive layer uses a special formula of the present invention, comprising the following components by weight: 55 parts of acrylate, 18 parts of hydrogenated terpene resin, 5 parts of cyclohexanone, 12 parts of hydrophobic silica, 8 parts of nano-alumina, 2 parts of epoxy soybean oil toughening agent, and 1 part of aziridine crosslinking agent.

[0047] Example 7 This embodiment provides a membrane switch that is sulfide-resistant and salt-spray-resistant. Compared with Example 2, the only difference is that the first adhesive layer uses a commercially available pressure-sensitive adhesive formula, while the second adhesive layer uses a special formula of the present invention, comprising the following components by weight: 50 parts of acrylate, 20 parts of hydrogenated C9 petroleum resin, 10 parts of cyclohexanone, 15 parts of nano-alumina, 10 parts of nano-calcium carbonate, 2 parts of epoxy soybean oil toughening agent, and 2 parts of aziridine crosslinking agent.

[0048] In summary, the present invention protects the circuits on the upper and lower diaphragms through upper and lower separators, improving their anti-sulfurization and salt spray resistance. Furthermore, by providing a waterproof, breathable membrane within the exhaust passage to block the flow of water vapor, water vapor is prevented from entering the press cavity through the exhaust passage, preventing oxidation and corrosion of the contacts and circuits. This also does not affect the air flow in and out of the press cavity, improving press comfort. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has high industrial value.

[0049] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A membrane switch that is resistant to sulfidation and salt spray, characterized in that: It includes an upper diaphragm and a lower diaphragm, and circuits are printed on the lower surface of the upper diaphragm and the upper surface of the lower diaphragm. A number of contacts are provided on the circuits. An upper partition layer and a lower partition layer are respectively provided below the upper diaphragm and above the lower diaphragm, and the upper partition layer and the lower partition layer are bonded together by a pressure-sensitive adhesive layer; the upper partition layer, the pressure-sensitive adhesive layer and the lower layer are provided with through holes penetrating in the up and down directions, and a pressing air cavity is formed between the hole walls of the through holes, the lower surface of the upper diaphragm and the upper surface of the lower diaphragm, and the contacts are located in the pressing air cavity; an exhaust channel connected to the pressing air cavity is provided on the pressure-sensitive adhesive layer, and a waterproof and breathable membrane is embedded in the opening of the exhaust channel connected to the outside world.

2. The anti-sulfurization and salt spray resistant membrane switch according to claim 1, characterized in that: The exhaust channel includes a main air channel and an auxiliary air channel. The first end of the main air channel is connected to the outside world, and the second end of the main air channel is connected to the pressing air cavity through the auxiliary air channel.

3. The anti-sulfurization and salt spray resistant membrane switch according to claim 2, characterized in that: The cross-sectional area of ​​the main air channel gradually increases from the second end to the first end, and the waterproof breathable membrane is embedded in the first end opening of the main air channel.

4. The anti-sulfurization and salt spray resistant membrane switch according to claim 1, characterized in that: The cross section of the exhaust passage is in an inverted trapezoidal shape.

5. The anti-sulfurization and salt spray resistant membrane switch according to any one of claims 1 to 4, characterized in that: The pressure-sensitive adhesive layer includes a first adhesive layer and a second adhesive layer. The second adhesive layer is arranged around the outer edge of the first adhesive layer. The pressing air cavity and the exhaust channel are in direct contact with the second adhesive layer. Under the same conditions, the fluidity of the second adhesive layer is less than that of the first adhesive layer.

6. The anti-sulfurization and salt spray resistant membrane switch according to claim 5, characterized in that: The second adhesive layer comprises a matrix resin, a tackifying resin, a solvent and a filler, and the content of the filler in the second adhesive layer is higher than that in the first adhesive layer; or the first adhesive layer does not contain a filler.

7. The anti-sulfurization and salt spray resistant membrane switch according to claim 5, characterized in that: The filler includes at least one of hydrophobically modified silicon dioxide, nano calcium carbonate, and nano alumina.

8. The anti-sulfurization and salt spray resistant membrane switch according to claim 1, characterized in that: The outer surface of the contact is covered with an isolation layer, and the isolation layer is formed by sintering conductive carbon paste or silver-palladium alloy paste.

9. A method for manufacturing a sulfide-resistant and salt-fog-resistant membrane switch according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. After the upper and lower diaphragms are made with circuits and contacts, they are rolled into a roll and the required holes are punched in advance. S2. Die-cut the upper and lower interlayers with release film, fully cut the through holes and other structural holes, and half cut the outer edges; fully cut means the substrate and release film are cut off, half cut means the substrate is cut off but the release film is not, and the release film is used as a carrier tape to form a roll; S3, positioning and laminating the upper film and the upper spacer, positioning and laminating the lower film and the lower spacer, and separating the release film after lamination; S4. Silk-screening pressure-sensitive adhesive on the upper or lower interlayer, with the silk-screen shape of the pressure-sensitive adhesive reserving an exhaust channel connected to each through hole; S5. The upper and lower partitions are bonded together with pressure-sensitive adhesive. After the lamination is completed, a waterproof and breathable membrane is filled in the end opening of the exhaust channel to obtain a membrane switch that is anti-sulfurization and salt spray resistant.

10. The manufacturing method according to claim 9, characterized in that: In step S4, the second adhesive layer is firstly screen-printed on the upper spacer or the lower spacer, and then the first adhesive layer is screen-printed after the second adhesive layer is semi-cured.

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