Fatigue-resistant diaphragm pump diaphragm sheet composite material and preparation method and application thereof

Abstract

The application relates to a kind of fatigue-resistant diaphragm pump diaphragm composite materials and its preparation method and application, belong to diaphragm pump membrane preparation technical field.The material includes framework layer and its both sides corrosion-resistant layer;Framework layer includes tetrafluoroethylene 40~60 parts, 1,4-butylenediol 20~40 parts, initiator 5~10 parts, liquefied MDI 80~100 parts, polytetramethylene ether glycol 20~40 parts, 1,4-butanediol 5~15 parts;Corrosion-resistant layer includes fluorine rubber 100 parts, peroxide vulcanizing agent 3~5 parts, vulcanization accelerator 0.5~5 parts, antioxidant 3~6 parts, stearic acid 1~3 parts, zinc oxide 2~6 parts.The diaphragm material provided in the application is used in cooperation with corrosion-resistant layer through framework layer, has good corrosion resistance and fatigue resistance, and significantly prolongs the service life of diaphragm material.

Description

Technical Field

[0001] This application relates to a fatigue-resistant diaphragm pump diaphragm composite material, its preparation method, and its application, belonging to the field of diaphragm pump diaphragm preparation technology. Background Technology

[0002] A diaphragm pump is a type of positive displacement pump that relies on the reciprocating motion of a diaphragm to change the volume of the working chamber, thereby drawing in and discharging liquid. A diaphragm pump mainly consists of a drive unit and a diaphragm cylinder head. The drive unit uses hydraulic transmission to move the diaphragm back and forth. The liquid being pumped is separated from the working liquid by the diaphragm within the pump cylinder, and only contacts the pump cylinder, the suction valve, the discharge valve, and the inner side of the diaphragm, without contacting the plunger or sealing devices.

[0003] The diaphragm is the core component of the diaphragm pump. On the one hand, the working environment of the medium transported by the diaphragm pump is harsh. On the other hand, when the diaphragm pump is working, the diaphragm swings back and forth continuously, and is subjected to flexural fatigue. Therefore, it needs to have flexibility and corrosion resistance.

[0004] In existing technologies, fluororubber is often used as the main material for diaphragms because it has good chemical stability. Its qualitative and physical-mechanical properties are widely used. For example, it can withstand most organic and inorganic solvents, but it is not resistant to organic solvents such as ketones, ethers, and esters. In addition, its resistance to flexural dynamic fatigue still needs to be improved. It is prone to fatigue damage, which can lead to diaphragm failure and leakage problems during use.

[0005] Therefore, it is necessary to provide a fatigue-resistant diaphragm pump diaphragm to meet the current performance requirements for diaphragms. Summary of the Invention

[0006] To address the aforementioned issues, this application provides a fatigue-resistant diaphragm pump diaphragm composite material, its preparation method, and its application. The diaphragm material provided in this application combines a skeleton layer and a corrosion-resistant layer, exhibiting both good corrosion resistance and fatigue resistance. Furthermore, the skeleton layer and the corrosion-resistant layer have good interfacial bonding properties, resulting in a long service life.

[0007] This application provides a method for preparing a fatigue-resistant diaphragm pump diaphragm composite material, characterized in that the preparation method includes the following steps: S1. Prepare the skeleton layer raw materials, which include, by weight parts: 40-60 parts of tetrafluoroethylene, 20-40 parts of 1,4-butenediol, 5-10 parts of initiator, 80-100 parts of liquefied MDI, 20-40 parts of polytetramethylene ether glycol, and 5-15 parts of 1,4-butenediol. S2. Prepare the skeleton layer material by reacting tetrafluoroethylene with 1,4-butene glycol and an initiator to generate a hydroxyl-containing fluoropolymer; react liquefied MDI with polytetramethylene ether glycol and 1,4-butene glycol to obtain an isocyanate prepolymer; mix and stir the hydroxyl-containing fluoropolymer with the isocyanate prepolymer to obtain the skeleton layer material, and press it into a sheet for later use. S3. Prepare the corrosion-resistant layer raw materials, which include, by weight parts: 100 parts of fluororubber, 3-5 parts of peroxide vulcanizing agent, 0.5-5 parts of vulcanization accelerator, 3-6 parts of antioxidant, 1-3 parts of stearic acid, and 2-6 parts of zinc oxide. S4. To prepare the corrosion-resistant layer material, fluororubber and antioxidant are mixed in the first stage; stearic acid and zinc oxide are added for the second stage; peroxide vulcanizing agent and vulcanization accelerator are added for the third stage; after being pressed into sheets, pre-vulcanization treatment is performed to obtain the corrosion-resistant layer material. S5. Take two corrosion-resistant layer sheets and one skeleton layer sheet, overlap them in the order of corrosion-resistant layer-skeleton layer-corrosion-resistant layer, and then perform hot pressing and vulcanization to obtain the fatigue-resistant diaphragm pump diaphragm composite material.

[0008] Optionally, the preparation of the skeleton layer material includes the following steps: reacting tetrafluoroethylene with 1,4-butenediol and an initiator in a nitrogen environment at 40-60°C for 6-12 hours to obtain a hydroxyl-containing fluoropolymer; reacting liquefied MDI with polytetramethylene ether glycol and 1,4-butenediol in a nitrogen environment at 60-80°C for 30-60 minutes under stirring to obtain an isocyanate prepolymer; mixing the hydroxyl-containing fluoropolymer with the isocyanate prepolymer and stirring for at least 30 minutes to obtain the skeleton layer material.

[0009] Optionally, the preparation of the corrosion-resistant layer material includes the following steps: fluororubber and antioxidant are mixed at 40-60°C for 3-5 minutes; stearic acid and zinc oxide are added and mixed at 40-60°C for 3-5 minutes; peroxide vulcanizing agent and vulcanization accelerator are added and mixed for 3-5 minutes; after pressing into sheets, pre-vulcanization is performed at 50-70°C for 10-15 minutes to obtain the corrosion-resistant layer material.

[0010] Optionally, step S5 specifically includes: taking two corrosion-resistant layer sheets and one skeleton layer sheet, overlapping them in the order of corrosion-resistant layer-skeleton layer-corrosion-resistant layer, and then hot-pressing and bonding them at 120~140℃ and vulcanizing them for 120~240 minutes to obtain the fatigue-resistant diaphragm pump diaphragm composite material.

[0011] Optionally, the fluororubber is a terpolymer, which is a terpolymer of vinylidene fluoride, tetrafluoroethylene, and hexafluoropropylene; the vinylidene fluoride accounts for 10 to 30 wt% of the total amount of the terpolymer.

[0012] Optionally, the vinylidene fluoride accounts for 20-30 wt% of the total amount of the terpolymer, and the tetrafluoroethylene accounts for 40-60 wt% of the total amount of the terpolymer. Optionally, the molecular weight of the fluororubber ranges from 50,000 to 200,000.

[0013] Optionally, the thickness of the skeleton layer is 0.2~0.5mm, and the ratio of the thickness of the skeleton layer to the total thickness of the corrosion-resistant layer is 1:(2~6). Optionally, the ratio of the thickness of the skeleton layer to the total thickness of the corrosion-resistant layer is 1:(4~6).

[0014] Optionally, the peroxide curing agent is one or more selected from bis(2,4-dichlorobenzoyl peroxide), benzoyl peroxide, dicumyl peroxide, and 2,5-dimethyl-2,5-bis(tert-butyl peroxide)hexane; and / or, The NCO content of the liquefied MDI is 10-20%; and / or, The initiator is one or more of azobisisobutyronitrile and azobisisoheptanenitrile; and / or The vulcanization accelerator is TAIC.

[0015] This application provides the fatigue-resistant diaphragm pump diaphragm composite material prepared by the above-mentioned method for preparing fatigue-resistant diaphragm pump diaphragm composite material.

[0016] This application provides the application of the above-mentioned fatigue-resistant diaphragm pump diaphragm composite material in diaphragm pump products.

[0017] The beneficial effects of this application include, but are not limited to: 1. The fatigue-resistant diaphragm pump diaphragm composite material, its preparation method, and its application according to this application, the diaphragm composite material provided by this application has a corrosion-resistant layer-skeleton layer-corrosion-resistant layer structure. By adding a skeleton layer material, which is prepared by mixing and reacting a hydroxyl-containing fluorine resin with an isocyanate prepolymer, this material, as an intermediate skeleton layer, can significantly improve the fatigue resistance of the diaphragm composite material, thereby significantly improving the flexural resistance and thus significantly extending the service life of the diaphragm.

[0018] 2. Based on the fatigue-resistant diaphragm pump diaphragm composite material, its preparation method, and its application, the selection of fluororubber was screened and tested. The terpolymer combination of vinylidene fluoride, tetrafluoroethylene, and hexafluoropropylene was determined, and the optimal addition ratio for fatigue resistance was determined, which significantly improved the fatigue resistance of the diaphragm.

[0019] 3. According to the fatigue-resistant diaphragm pump diaphragm composite material, its preparation method and application, by optimizing the hot pressing bonding and vulcanization process of the corrosion-resistant layer-skeleton layer-corrosion-resistant layer, and by selecting the preferred peroxide vulcanizing agent, vulcanization accelerator and initiator, the interfacial compatibility between the corrosion-resistant layer and the skeleton layer can be significantly improved, the bonding performance is better and the product has better stability in use. Detailed Implementation

[0020] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments. Unless otherwise specified, the raw materials and reagents in the embodiments of the present application are all purchased through commercial channels.

[0021] Example 1 1) Preparation of the framework layer Prepare the backbone layer raw materials, which include, by weight: 50 parts of tetrafluoroethylene, 30 parts of 1,4-butene glycol, 8 parts of azobisisobutyronitrile initiator, 90 parts of liquefied MDI (carbodiimide-urea ketimide modified MDI, NCO content 15%), 30 parts of polytetramethylene ether glycol (molecular weight range 2000~4000), and 10 parts of 1,4-butene glycol. Prepare a high-pressure reactor, add 1,4-butenediol and azobisisobutyronitrile initiator, seal the reactor and purge the air with nitrogen to obtain a nitrogen reaction environment, purge with tetrafluoroethylene and heat to 50°C for 10 hours to obtain hydroxyl-containing fluororesin. Prepare a reaction vessel, add liquefied MDI, polytetramethylene ether glycol, and 1,4-butanediol, then seal the reaction vessel and purge the air with nitrogen to obtain a nitrogen reaction environment. React at 70°C for 45 minutes under stirring to obtain isocyanate prepolymer. The obtained hydroxyl-containing fluoropolymer was mixed with isocyanate prepolymer at room temperature and stirred for 30 min to obtain the skeleton layer material, which was then pressed into sheets for later use. 2) Preparation of corrosion-resistant layer Prepare the corrosion-resistant layer raw materials, which, by weight, include: 100 parts of fluororubber (molecular weight range 50,000 to 200,000), 4 parts of bis(2,4-dichlorobenzoyl peroxide), 3 parts of TAIC vulcanization accelerator, 5 parts of antioxidant AW, 2 parts of stearic acid, and 4 parts of zinc oxide; in the terpolymer, the amount of vinylidene fluoride is 25 wt%, the amount of tetrafluoroethylene is 50 wt%, and the amount of hexafluoropropylene is 25 wt%.

[0022] Fluororubber and antioxidant are mixed at 50°C for 4 minutes. Add stearic acid and zinc oxide and continue the second stage of mixing at 50°C for 4 minutes. Add peroxide vulcanizing agent and vulcanization accelerator and carry out three-stage mixing, with a mixing time of 4 minutes; After being pressed into sheets, the material is pre-vulcanized at 60°C for 12 minutes to obtain a corrosion-resistant layer material. 3) Hot pressing bonding and vulcanization Two corrosion-resistant layer sheets and one skeleton layer sheet are taken. The skeleton layer thickness is 0.4 mm, and the ratio of the skeleton layer thickness to the total thickness of the corrosion-resistant layer is 1:4. The corrosion-resistant layer-skeleton layer-corrosion-resistant layer are overlapped in sequence. Then, a flat vulcanizing machine is used to hot-press and bond the sheets at 130℃ and 1MPa pressure for 180 min to obtain a fatigue-resistant diaphragm pump diaphragm composite material.

[0023] Example 2 1) Preparation of the framework layer Prepare the backbone layer raw materials, which include, by weight: 40 parts tetrafluoroethylene, 20 parts 1,4-butene glycol, 5 parts azobisisobutyronitrile initiator, 80 parts liquefied MDI (carbodiimide-urea ketimide modified MDI, NCO content 15%), 20 parts polytetramethylene ether glycol (molecular weight range 2000~4000), and 5 parts 1,4-butene glycol. Prepare a high-pressure reactor, add 1,4-butenediol and azobisisobutyronitrile initiator, seal the reactor and purge the air with nitrogen to obtain a nitrogen reaction environment, purge with tetrafluoroethylene and heat to 40℃ for 12 hours to obtain hydroxyl-containing fluororesin. Prepare a reaction vessel, add liquefied MDI, polytetramethylene ether glycol, and 1,4-butanediol, then seal the reaction vessel and purge the air with nitrogen to obtain a nitrogen reaction environment. React at 60°C for 60 min under stirring to obtain isocyanate prepolymer. The obtained hydroxyl-containing fluoropolymer was mixed with isocyanate prepolymer at room temperature and stirred for 30 min to obtain the skeleton layer material, which was then pressed into sheets for later use. 2) Preparation of corrosion-resistant layer Prepare the corrosion-resistant layer raw materials, which, by weight, include: 100 parts of fluororubber (molecular weight range 50,000 to 200,000), 3 parts of benzoyl peroxide, 0.5 parts of TAIC vulcanization accelerator, 3 parts of antioxidant AW, 1 part of stearic acid, and 2 parts of zinc oxide; in the terpolymer, the amount of vinylidene fluoride is 20 wt%, the amount of tetrafluoroethylene is 40 wt%, and the amount of hexafluoropropylene is 40 wt%.

[0024] Fluororubber and antioxidant are mixed at 60°C for 3 minutes. Add stearic acid and zinc oxide and continue the second stage of mixing at 60℃ for 3 minutes. Add peroxide vulcanizing agent and vulcanization accelerator and carry out three-stage mixing, with a mixing time of 3 minutes; After being pressed into sheets, the material is pre-vulcanized at 70°C for 10 minutes to obtain a corrosion-resistant layer material. 3) Hot pressing bonding and vulcanization Two corrosion-resistant layer sheets and one skeleton layer sheet are taken. The skeleton layer thickness is 0.2 mm, and the ratio of the skeleton layer thickness to the total thickness of the corrosion-resistant layer is 1:6. The corrosion-resistant layer-skeleton layer-corrosion-resistant layer are overlapped in sequence. Then, a flat vulcanizing machine is used to hot-press and bond the sheets at 120℃ and 1MPa pressure for 120 minutes to obtain a fatigue-resistant diaphragm pump diaphragm composite material.

[0025] Example 3 1) Preparation of the framework layer Prepare the backbone layer raw materials, which include, by weight: 60 parts tetrafluoroethylene, 40 parts 1,4-butene glycol, 10 parts azobisisobutyronitrile initiator, 100 parts liquefied MDI (carbodiimide-urea ketimide modified MDI, NCO content 15%), 40 parts polytetramethylene ether glycol (molecular weight range 2000~4000), and 15 parts 1,4-butene glycol; Prepare a high-pressure reactor, add 1,4-butenediol and azobisisobutyronitrile initiator, seal the reactor and purge the air with nitrogen to obtain a nitrogen reaction environment, purge with tetrafluoroethylene and heat to 60℃ for 6 hours to obtain hydroxyl-containing fluororesin. Prepare a reaction vessel, add liquefied MDI, polytetramethylene ether glycol, and 1,4-butanediol, then seal the reaction vessel and purge the air with nitrogen to obtain a nitrogen reaction environment. React at 80°C for 30 minutes under stirring to obtain isocyanate prepolymer. The obtained hydroxyl-containing fluoropolymer was mixed with isocyanate prepolymer at room temperature and stirred for 30 min to obtain the skeleton layer material, which was then pressed into sheets for later use. 2) Preparation of corrosion-resistant layer Prepare the corrosion-resistant layer raw materials, which include, by weight, 100 parts of fluororubber (molecular weight range 50,000 to 200,000), 5 parts of dicumyl peroxide, 5 parts of TAIC vulcanization accelerator, 6 parts of antioxidant AW, 3 parts of stearic acid, and 6 parts of zinc oxide; in the terpolymer, the amount of vinylidene fluoride is 30 wt%, the amount of tetrafluoroethylene is 60 wt%, and the amount of hexafluoropropylene is 10 wt%.

[0026] Fluororubber and antioxidant are mixed at 40°C for 5 minutes. Add stearic acid and zinc oxide and continue the second stage of mixing at 40℃ for 5 minutes. Add peroxide vulcanizing agent and vulcanization accelerator and carry out three-stage mixing for 5 minutes; After being pressed into sheets, the material is pre-vulcanized at 50°C for 15 minutes to obtain a corrosion-resistant layer material. 3) Hot pressing bonding and vulcanization Two corrosion-resistant layer sheets and one skeleton layer sheet are taken. The skeleton layer thickness is 0.5 mm, and the ratio of the skeleton layer thickness to the total thickness of the corrosion-resistant layer is 1:2. The corrosion-resistant layer-skeleton layer-corrosion-resistant layer are overlapped in sequence. Then, a flat vulcanizing machine is used to hot-press and bond the sheets at 140℃ and 1MPa pressure for 240 minutes to obtain a fatigue-resistant diaphragm pump diaphragm composite material.

[0027] Comparative Example 1 Compared with Example 1, this comparative example does not contain an intermediate skeleton layer, the diaphragm only contains a corrosion-resistant layer, and the thickness of the diaphragm is the same as that of Example 1.

[0028] Comparative Example 2 This comparative example is basically the same as Example 1, except that in step S5, hot pressing and vulcanization are performed at 110°C for 30 minutes.

[0029] Comparative Example 3 This comparative example is basically the same as Example 1, except that in step S5, hot pressing and vulcanization are performed at 150°C for 30 minutes.

[0030] Comparative Example 4 This comparative example is basically the same as Example 1, except that the bis(2,4-dichlorobenzoyl peroxide) peroxide vulcanizing agent is replaced with an equal amount of sulfur, and the initiator azobisisobutyronitrile is replaced with an equal amount of benzoyl peroxide / N,N-dimethylaniline.

[0031] Comparative Example 5 This comparative example is basically the same as Example 1, except that the bis(2,4-dichlorobenzoyl peroxide) peroxide vulcanizing agent is replaced with an equal amount of tetramethylthiuram disulfide TMTD, and the initiator azobisisobutyronitrile is replaced with an equal amount of diperperoxytert-butyl oxalate.

[0032] Comparative Example 6 This comparative example is basically the same as Example 1, except that tetrafluoroethylene accounts for 30 wt% of the total amount of the terpolymer, vinylidene fluoride accounts for 50 wt% of the total amount of the terpolymer, and hexafluoropropylene accounts for 20 wt% of the total amount of the terpolymer.

[0033] Test Example 1 The acid and alkali corrosion resistance performance is in accordance with GB / T1690-2010. The samples to be tested are subjected to acid and alkali resistance treatment. After the acid and alkali corrosion resistance treatment, the flexural fatigue resistance and bending fatigue performance are tested. The bending fatigue performance test is in accordance with GB / T35465.1-2017. The bending fatigue life (ten thousand cycles) is tested, and the appearance of the first-level crack is taken as the standard.

[0034] The test results are shown in Table 1 below.

[0035] Table 1. Diaphragm performance test results

[0036] As shown in Table 1, the diaphragm material provided in this application has significantly improved fatigue resistance. Furthermore, no separation between the corrosion-resistant layer and the skeleton layer was observed before the bending fatigue life was reached during the experiment, indicating that the interface between the corrosion-resistant layer and the skeleton layer is well bonded. Moreover, the addition of the skeleton layer in the middle of the corrosion-resistant layer has a significant effect on improving the bending fatigue life.

[0037] As can be seen from the comparison of Comparative Example 1, the solution of this application has a significant advantage in fatigue resistance compared with the prior art of pure polytetrafluoroethylene material or single-structure diaphragm sheets based on polytetrafluoroethylene material.

[0038] According to the comparison of Comparative Examples 2 and 3, the hot pressing bonding and vulcanization temperature in step S5 have a significant impact. If the temperature is too low, it will affect the continued vulcanization performance of the corrosion-resistant layer. If the vulcanization temperature is too high, the high temperature resistance of the skeleton layer is much worse than that of the corrosion-resistant layer material. Processing temperatures above or close to 150°C may cause high-temperature degradation and a decrease in performance.

[0039] As can be seen from the comparison of Comparative Examples 4 and 5, the corrosion-resistant layer prepared by selecting a peroxide vulcanizing agent and the initiator of azobisisobutyronitrile or azobisisoheptanenitrile skeleton layer in this application has better fatigue resistance of both the corrosion-resistant layer and the skeleton layer. In addition, the vulcanization speed of the peroxide vulcanizing agent is relatively slow, which makes it more suitable for the low-temperature pre-vulcanization and subsequent hot-press bonding and vulcanization process of the corrosion-resistant layer in this application, and the fatigue resistance of the prepared corrosion-resistant layer is better.

[0040] As can be seen from the comparison of Comparative Example 6, the fatigue resistance of the corrosion-resistant layer is significantly improved by optimizing the selection of terpolymers and combining them in a specific ratio in the present application.

[0041] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for preparing a fatigue-resistant diaphragm pump diaphragm composite material, characterized in that, The preparation method includes the following steps: S1. Prepare the skeleton layer raw materials, which include, by weight parts: 40-60 parts of tetrafluoroethylene, 20-40 parts of 1,4-butenediol, 5-10 parts of initiator, 80-100 parts of liquefied MDI, 20-40 parts of polytetramethylene ether glycol, and 5-15 parts of 1,4-butenediol. S2. Prepare the skeleton layer material by reacting tetrafluoroethylene with 1,4-butene glycol and an initiator to generate a hydroxyl-containing fluoropolymer; react liquefied MDI with polytetramethylene ether glycol and 1,4-butene glycol to obtain an isocyanate prepolymer; mix and stir the hydroxyl-containing fluoropolymer with the isocyanate prepolymer to obtain the skeleton layer material, and press it into a sheet for later use. S3. Prepare the corrosion-resistant layer raw materials, which include, by weight parts: 100 parts of fluororubber, 3-5 parts of peroxide vulcanizing agent, 0.5-5 parts of vulcanization accelerator, 3-6 parts of antioxidant, 1-3 parts of stearic acid, and 2-6 parts of zinc oxide. S4. To prepare the corrosion-resistant layer material, fluororubber and antioxidant are mixed in the first stage; stearic acid and zinc oxide are added for the second stage; peroxide vulcanizing agent and vulcanization accelerator are added for the third stage; after being pressed into sheets, pre-vulcanization treatment is performed to obtain the corrosion-resistant layer material. S5. Take two corrosion-resistant layer sheets and one skeleton layer sheet, overlap them in the order of corrosion-resistant layer-skeleton layer-corrosion-resistant layer, and then perform hot pressing and vulcanization to obtain the fatigue-resistant diaphragm pump diaphragm composite material.

2. The method for preparing the fatigue-resistant diaphragm pump diaphragm composite material according to claim 1, characterized in that, The preparation of the skeleton layer material includes the following steps: reacting tetrafluoroethylene with 1,4-butenediol and an initiator in a nitrogen environment at 40-60°C for 6-12 hours to obtain a hydroxyl-containing fluoropolymer; reacting liquefied MDI with polytetramethylene ether glycol and 1,4-butenediol in a nitrogen environment at 60-80°C for 30-60 minutes under stirring to obtain an isocyanate prepolymer; mixing and stirring the hydroxyl-containing fluoropolymer with the isocyanate prepolymer for at least 30 minutes to obtain the skeleton layer material.

3. The method for preparing the fatigue-resistant diaphragm pump diaphragm composite material according to claim 1, characterized in that, The preparation of the corrosion-resistant layer material includes the following steps: fluororubber and antioxidant are mixed at 40-60°C for 3-5 minutes; stearic acid and zinc oxide are added and mixed at 40-60°C for 3-5 minutes; peroxide vulcanizing agent and vulcanization accelerator are added and mixed for 3-5 minutes; after pressing into sheets, pre-vulcanization is performed at 50-70°C for 10-15 minutes to obtain the corrosion-resistant layer material.

4. The method for preparing the fatigue-resistant diaphragm pump diaphragm composite material according to claim 1, characterized in that, Step S5 specifically includes: taking two corrosion-resistant layer sheets and one skeleton layer sheet, overlapping them in the order of corrosion-resistant layer-skeleton layer-corrosion-resistant layer, and then hot-pressing and bonding them at 120~140℃ and vulcanizing them for 120~240 minutes to obtain the fatigue-resistant diaphragm pump diaphragm sheet composite material.

5. The method for preparing the fatigue-resistant diaphragm pump diaphragm composite material according to claim 1, characterized in that, The fluororubber is a terpolymer, which is composed of vinylidene fluoride, tetrafluoroethylene, and hexafluoropropylene; the vinylidene fluoride accounts for 10-30 wt% of the total amount of the terpolymer.

6. The method for preparing the fatigue-resistant diaphragm pump diaphragm composite material according to claim 5, characterized in that, The vinylidene fluoride accounts for 20-30 wt% of the total amount of the terpolymer, and the tetrafluoroethylene accounts for 40-60 wt% of the total amount of the terpolymer.

7. The method for preparing the fatigue-resistant diaphragm pump diaphragm composite material according to claim 1, characterized in that, The thickness of the skeleton layer is 0.2~0.5mm, and the ratio of the thickness of the skeleton layer to the total thickness of the corrosion-resistant layer is 1:(2~6). Optionally, the ratio of the thickness of the skeleton layer to the total thickness of the corrosion-resistant layer is 1:(4~6).

8. The method for preparing the fatigue-resistant diaphragm pump diaphragm composite material according to claim 1, characterized in that, The peroxide vulcanizing agent is one or more selected from bis(2,4-dichlorobenzoyl peroxide), benzoyl peroxide, dicumyl peroxide, and 2,5-dimethyl-2,5-bis(tert-butyl peroxide)hexane; and / or, The NCO content of the liquefied MDI is 10-20%; and / or, The initiator is one or more of azobisisobutyronitrile and azobisisoheptanenitrile; and / or The vulcanization accelerator is TAIC.

9. The fatigue-resistant diaphragm pump diaphragm composite material prepared by the method for preparing fatigue-resistant diaphragm pump diaphragm composite material according to any one of claims 1 to 8.

10. The application of the fatigue-resistant diaphragm pump diaphragm composite material as described in claim 9 in diaphragm pump products.

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