Low-leakage breathing valve composite diaphragm and preparation method and application thereof

Abstract

The present application relates to the technical field of breathing valve sealing, and discloses a low-leakage breathing valve composite diaphragm and a preparation method and application thereof.The composite diaphragm comprises a polymer sheet layer and a fluororubber composite material layer, wherein the thickness of the polymer sheet layer is 0.1-1 mm; and the fluororubber composite material layer is prepared from a raw material composition containing fluororubber, inorganic filler, acid absorbent, vulcanizing agent, release agent and colorant.The composite diaphragm provided by the present application has a leakage of 0.0001 m 3 / hour at most when used in a breathing valve with a nominal diameter of 150 mm or below at a temperature of 20 DEG C and 0.75 times the opening pressure of the storage tank, and a leakage of 0.0002 m 3 / hour at most when used in a breathing valve with a nominal diameter of 200 mm or above at a temperature of 20 DEG C and 0.75 times the opening pressure of the storage tank.

Description

Technical Field

[0001] This invention relates to the field of breather valve sealing technology, specifically to a low-leakage breather valve composite diaphragm, its preparation method, and its application. Background Technology

[0002] A breather valve is a valve that ensures the storage tank is isolated from the atmosphere within a certain pressure range, while allowing it to breathe when the pressure exceeds or falls below this range. Its function is to prevent damage to the storage tank due to overpressure or vacuum, and to reduce evaporation losses of the stored medium. Installing a breather valve not only reduces gas emissions from the tank, thus lowering atmospheric pollution, but also prevents damage from overpressure or instability from excessive vacuum, contributing to both safety and environmental protection. Summary of the Invention

[0003] The purpose of this invention is to overcome the problems of high leakage and high safety risks associated with traditional breather valve diaphragms (gaskets) in existing technologies, and to provide a low-leakage composite diaphragm for breather valves, its preparation method, and its application. This invention achieves low leakage in storage tank breather valves by improving the performance of composite fluororubber diaphragms.

[0004] To achieve the above objectives, the present invention provides a low-leakage breather valve composite diaphragm, the composite diaphragm comprising a polymer sheet layer and a fluororubber composite material layer.

[0005] The thickness of the polymer sheet is 0.1–1 mm;

[0006] The fluororubber composite material layer is made from a raw material composition containing fluororubber, inorganic filler, acid absorber, vulcanizing agent, release agent and colorant.

[0007] Preferably, the polymer sheet in the polymer layer is selected from one or more of polyetheretherketone, polytetrafluoroethylene and polyimide.

[0008] Preferably, in the raw material composition, the fluororubber is type 26 fluororubber or type 246 fluororubber.

[0009] Preferably, in the raw material composition, the inorganic filler is selected from one or more of silica, calcium silicate, magnesium silicate, aluminum silicate, calcium carbonate, barium sulfate, diatomaceous earth, graphite, silicon nitride, and boron nitride.

[0010] Preferably, in the raw material composition, the acid absorbent is selected from one or more of magnesium oxide, calcium oxide, zinc oxide and calcium hydroxide.

[0011] Preferably, in the raw material composition, the vulcanizing agent is selected from one or more of N,N'-biscinnamaldehyde-1,6-hexanediamine, 2,2-(4-hydroxyphenyl)hexafluoropropane, dicumyl peroxide and 2,5-dimethyl-2,5-ditert-butylperoxide.

[0012] Preferably, in the raw material composition, the release agent is selected from one or more of zinc stearate, ammonium stearate, and paraffin wax.

[0013] Preferably, in the raw material composition, the colorant is selected from one or more of iron oxide red, colloidal graphite and carbon black.

[0014] Preferably, in the raw material composition, the weight ratio of the fluororubber, the inorganic filler, the acid absorber, the vulcanizing agent, the mold release agent and the colorant is 100:10-60:0.001-20:0.001-5:0.2-2:0.001-3.

[0015] Preferably, the raw material composition further contains a vulcanization accelerator.

[0016] Preferably, the weight ratio of the fluororubber to the vulcanization accelerator is 100:0.001 to 2.

[0017] Preferably, the vulcanization accelerator is triallyl isocyanurate.

[0018] Preferably, the thickness ratio of the polymer sheet to the fluororubber composite layer is 1:1 to 2.

[0019] A second aspect of the present invention provides a method for using the low-leakage breather valve composite diaphragm, the method comprising:

[0020] (1) Preparation of fluororubber composite material: The raw material composition is mixed and then the resulting product is refined multiple times to obtain fluororubber composite material;

[0021] (2) Preparation of composite membranes:

[0022] The polymer sheet and the fluororubber composite material are thermally bonded together and then vulcanized to obtain a composite film.

[0023] Preferably, in step (1), the mixing conditions include: a temperature of 50-80°C, a time of 15-60 min, and a rotation speed of 20-60 rpm.

[0024] Preferably, in step (1), the refining conditions include: a temperature of 100-140°C, a refining cycle of 10-30 times, and a roller gap of 0.2-4 mm.

[0025] Preferably, in step (2), the conditions for thermal bonding include: a temperature of 150-160°C and a time of 1-10 min.

[0026] Preferably, in step (2), the vulcanization conditions include a temperature of 180–240°C and a time of 8–24 hours.

[0027] A third aspect of the present invention provides a low-leakage breather valve composite diaphragm prepared by the method described above.

[0028] The fourth aspect of the present invention provides a composite diaphragm as described above, or the application of the composite diaphragm as described above, as a sealing material for a breather valve.

[0029] The composite diaphragm provided by the present invention comprises a polymer sheet layer of a specific thickness and a fluororubber composite material layer. The composite diaphragm has good yield deformation in the leakage range from above 0.75 times the opening pressure of the breather valve to below the opening pressure, thereby reducing the leakage of the breather valve.

[0030] Furthermore, the leakage rate of the composite diaphragm provided by this invention at a temperature of 20°C and a breather valve opening pressure of 0.75 times is as follows: for diaphragms used in breather valves with a nominal diameter of 150mm and below, the leakage rate can be as low as 0.0001m³ per hour. 3 For breather valves with a nominal diameter of 200mm and above, the diaphragm leakage rate can be as low as 0.0002m³ per hour. 3 It is far below the relevant standards for leakage of breather valves both domestically and internationally. Attached Figure Description

[0031] Figure 1 This is a flowchart illustrating the preparation of a low-leakage breather valve composite diaphragm as described in this invention. Detailed Implementation

[0032] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0033] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0034] A first aspect of the present invention provides a low-leakage breather valve composite diaphragm, the composite diaphragm comprising a polymer sheet layer and a fluororubber composite material layer. The fluororubber composite material layer is bonded to one side of the polymer sheet layer.

[0035] In this invention, the polymer sheet supports the composite diaphragm, preventing the diaphragm from being too soft and sagging at the edges, which would cause leakage in the breather valve. Lubricants and thermal conductive agents are added during the pretreatment of the polymer sheet, giving it good lubricity, thermal conductivity, and anti-friction properties. The fluororubber composite layer has good elasticity, and appropriate elastic deformation gives the breather valve excellent sealing performance. Combining the polymer sheet and the fluororubber composite layer can significantly reduce the leakage of the breather valve.

[0036] In this invention, the thickness of the polymer sheet should be appropriate. If it is too thick, the membrane will be too hard overall and the surface will be uneven and concave, which will not achieve the effect of reducing the leakage of the breather valve.

[0037] In this invention, the thickness of the polymer sheet is 0.1–1 mm. In specific embodiments, the thickness of the polymer sheet can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1 mm.

[0038] In this invention, the polymer sheet refers to the material forming the polymer sheet layer. In specific embodiments, the polymer sheet forming the polymer sheet layer can be a material well known to those skilled in the art. In a preferred embodiment, the polymer sheet in the polymer sheet layer can be selected from one or more of polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE), and polyimide (PI).

[0039] In a specific embodiment, the polymer sheet is entirely formed of polymer sheet material, and the polymer sheet material needs to be pretreated before use. The pretreatment includes: adding lubricant and thermal conductive agent to enhance its lubricity, thermal conductivity and anti-friction properties, and performing surface treatment on the polymer sheet material.

[0040] Through research, the inventors discovered that, in this invention, a composite membrane composed of a fluororubber composite material layer prepared from a raw material containing fluororubber and the polymer sheet layer, as a sealing material for a breather valve, can significantly reduce leakage.

[0041] In this invention, the fluororubber composite material layer is made from a raw material composition containing fluororubber, inorganic filler, acid absorber, vulcanizing agent, release agent, and colorant. The fluororubber composite material layer is obtained by mixing, refining, thermally bonding, and vulcanizing the raw material composition.

[0042] In this invention, the fluororubber can be any fluororubber well-known in the art, as long as it can maintain the gasket shape and mechanical strength in oily, acidic, or alkaline environments. In a specific embodiment, the fluororubber in the raw material composition can be type 26 fluororubber and / or type 246 fluororubber.

[0043] In this invention, the inorganic filler can be a conventional choice in the art, as long as it can fill the rubber. In a preferred embodiment, in order to ensure that the diaphragm has good yield deformation in the leakage range above and below the opening pressure of the breather valve, and to further reduce the leakage of the breather valve, the inorganic filler in the raw material composition is selected from one or more of silica, calcium silicate, magnesium silicate, aluminum silicate, calcium carbonate, barium sulfate, diatomaceous earth, graphite, silicon nitride, and boron nitride.

[0044] In this invention, the acid absorber refers to an additive capable of absorbing acidic substances released during the rubber manufacturing process. The acid absorber can be a conventional choice in the art, as long as it can absorb the acidic substances released during rubber manufacturing. In a preferred embodiment, in the raw material composition, the acid absorber is selected from one or more of magnesium oxide, calcium oxide, zinc oxide, and calcium hydroxide.

[0045] In this invention, the vulcanizing agent can be a conventional choice in the art. In a specific embodiment, in the raw material composition, the vulcanizing agent is selected from one or more of N,N'-biscinnamaldehyde-1,6-hexanediamine, 2,2-(4-hydroxyphenyl)hexafluoropropane, dicumyl peroxide, and 2,5-dimethyl-2,5-di-tert-butylperoxide.

[0046] In this invention, the release agent can be a release agent well known to those skilled in the art. In a specific embodiment, in the raw material composition, the release agent is selected from one or more of zinc stearate, ammonium stearate, and paraffin wax.

[0047] In this invention, the colorant can be any colorant well-known to those skilled in the art, as long as it can color the composite film. In a specific embodiment, the colorant in the raw material composition is selected from one or more of iron oxide red, colloidal graphite, and carbon black.

[0048] In this invention, in order to improve the yield recovery performance of the fluororubber composite material layer and thereby reduce the leakage of the breather valve, it is necessary to reasonably control the amount of the fluororubber, the inorganic filler, the acid absorber, the vulcanizing agent, the release agent and the colorant.

[0049] In this invention, in a specific embodiment, the weight ratio of the fluororubber, the inorganic filler, the acid absorber, the vulcanizing agent, the mold release agent, and the colorant in the raw material composition can be 100:10-60:0.001-20:0.001-5:0.2-2:0.001-3, for example 100:10:0.28:0.15:1.89:1.54, or 100:60:0.5. 4:2.16:1.55:2.05, 100:20:10:2.5:1.6:2.5, 100:50:10.8:3.85:0.88:2.35, 100:30:0.2:0.1:1:1.5, 100:40:10.5:1.25:1.58:0.55, 100:10:0.2:0.1:1:1.5, 100:60:20:5:2:3.

[0050] In this invention, the addition of a vulcanization accelerator to the raw materials used to prepare the fluororubber composite layer is selected according to actual needs. In a specific embodiment, the raw material composition also contains a vulcanization accelerator. In a preferred embodiment, the weight ratio of the fluororubber to the vulcanization accelerator is 100:0.001 to 2, for example, 100:0.001, 100:0.1, 100:0.2, 100:0.5, 100:0.6, 100:0.7, 100:0.8, 100:0.9, or 100:1. Specifically, the vulcanization accelerator is triallyl isocyanurate.

[0051] In this invention, to meet basic usage requirements, the thicknesses of the polymer sheet and the fluororubber composite layer need to satisfy a certain relationship. In specific embodiments, the thickness of the fluororubber composite layer is approximately equal to the thickness of the polymer sheet, or the thickness of the fluororubber composite layer is greater than that of the polymer sheet. In a preferred embodiment, the thickness ratio of the polymer sheet to the fluororubber composite layer is 1:1 to 4, for example, 1:1, 1:1.2, 1:1.4, 1:1.5, 1:1.6, 1:1.8, 1:2, 1:2.2, 1:2.4, 1:2.5, 1:2.6, 1:2.8, 1:3, 1:3.2, 1:3.4, 1:3.6, 1:3.8, or 1:4.

[0052] A second aspect of the present invention provides a method for preparing the low-leakage breather valve composite diaphragm described in the first aspect above, the method comprising:

[0053] (1) Preparation of fluororubber composite material: The raw material composition is mixed and then the resulting product is refined multiple times to obtain fluororubber composite material;

[0054] (2) Preparation of composite membranes:

[0055] The polymer sheet and the fluororubber composite material are thermally bonded together and then vulcanized to obtain a composite film.

[0056] The method of the present invention first prepares fluororubber composite material by mixing and refining, and then thermally bonds and vulcanizes the polymer sheet with the fluororubber composite material to obtain a composite film including a fluororubber composite material layer and a polymer sheet layer.

[0057] In this invention, the mixing process can be performed according to conventional operations in the art. In a preferred embodiment, in step (1), the mixing temperature can be 50–80°C, for example, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, or 80°C. In a preferred embodiment, in step (1), the mixing time can be 15–60 min, for example, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, or 60 min. In a preferred embodiment, in step (1), the mixing speed can be 20–60 rpm, for example, 20 rpm, 25 rpm, 30 rpm, 35 rpm, 40 rpm, 45 rpm, 50 rpm, 55 rpm, or 60 rpm. In this invention, the mixing is performed using a Baisheng Company BL-6175-B model mixing machine.

[0058] In the method described in this invention, the refining process can be performed according to conventional operations in the art. In a preferred embodiment, in step (1), the refining temperature is 100–140°C, for example, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, or 140°C. In a preferred embodiment, in step (1), the number of refining cycles is 10, 15, 20, 25, or 30. In a preferred embodiment, the roller gap is 0.2–4 mm, for example, 0.2 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, or 4 mm. In this invention, the refining is performed using a Meissen Machinery MRM480 ​​mixing mill. In this invention, one refining cycle refers to the rollers rolling once over the mixed raw material.

[0059] In the method described in this invention, the thermal bonding can be a conventional choice in the art. In a preferred embodiment, in step (2), the thermal bonding temperature is 150–160°C, for example, 150°C, 151°C, 152°C, 153°C, 154°C, 155°C, 156°C, 157°C, 158°C, 159°C, or 160°C. In a preferred embodiment, in step (2), the thermal bonding time is 1–10 min, for example, 1 min, 2 min, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min, or 10 min.

[0060] In the method described in this invention, the vulcanization process can be carried out according to conventional operations in the art. To ensure the diaphragm has good yield deformation in the leakage range above and below the breather valve's opening pressure (0.75 times the opening pressure), and to further reduce the breather valve leakage, the vulcanization conditions can be controlled within an appropriate range. In a preferred embodiment, in step (2), the vulcanization temperature can be 180–240°C, for example, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, or 240°C. In a preferred embodiment, in step (2), the vulcanization time is 8–24 hours, for example, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours, or 24 hours.

[0061] In one specific embodiment, the method for preparing the low-leakage breather valve composite diaphragm includes the following steps:

[0062] (1) Preparation of fluororubber composite material: Fluororubber, inorganic filler, acid absorber, vulcanizing agent, release agent and colorant are mixed. The mixing temperature is 50-80℃, the time is 15-60min, and the rotation speed is 20-60 rpm. The weight ratio of the fluororubber, inorganic filler, acid absorber, vulcanizing agent, release agent and colorant is 100:10-60:0.001-20:0.001-5:0.2-2:0.001-3. Then the obtained product is refined 10-30 times. The refining temperature is 100-140℃ and the roller gap is 0.2-4mm to obtain fluororubber composite material.

[0063] (2) Preparation of composite membranes:

[0064] A polymer sheet with a thickness of 0.1 to 1 mm and the fluororubber composite material are thermally bonded at a temperature of 150 to 160°C for 1 to 10 minutes, followed by vulcanization at a temperature of 180 to 240°C for 8 to 24 hours to obtain a composite film.

[0065] In another specific embodiment, the method for preparing the low-leakage breather valve composite diaphragm includes the following steps:

[0066] (1) Preparation of fluororubber composite material: Fluororubber, inorganic filler, acid absorber, vulcanizing agent, release agent, colorant and vulcanization accelerator are mixed. The mixing temperature is 50-80℃, the time is 15-60min, and the rotation speed is 20-60 rpm. The weight ratio of the fluororubber, inorganic filler, acid absorber, vulcanizing agent, release agent and colorant is 100:10-60:0.001-20:0.001-5:0.2-2:0.001-3:0.001-2. Then the obtained product is refined 10-30 times. The refining temperature is 100-140℃ and the roller gap is 0.2-4mm to obtain fluororubber composite material.

[0067] (2) Preparation of composite membranes:

[0068] A polymer sheet with a thickness of 0.1 to 1 mm and the fluororubber composite material are thermally bonded at a temperature of 150 to 160°C for 1 to 10 minutes, followed by vulcanization at a temperature of 180 to 240°C for 8 to 24 hours to obtain a composite film.

[0069] A third aspect of this invention provides an ultra-low leakage composite diaphragm for a breather valve prepared by the method described above. The composite diaphragm prepared by the method of this invention, when used in breather valves with a nominal diameter of 150 mm or less, exhibits a leakage rate as low as 0.0001–0.0016 m³ / s at a temperature of 20°C and 0.75 times the opening pressure of the tank breather valve. 3 The composite diaphragm prepared by the method described in this invention, when used in breather valves with a nominal diameter of 200 mm or more, exhibits a leakage rate as low as 0.0002–0.0042 m³ / s at a temperature of 20°C and an opening pressure of 0.75 times that of the breather valve. 3 In this invention, the "nominal diameter" refers to the nominal diameter of the breather valve connecting flange.

[0070] The fourth aspect of the present invention provides the application of the composite diaphragm described in the first aspect or the composite diaphragm described in the third aspect as a sealing material for a breather valve.

[0071] The present invention will be described in detail below through embodiments, but the scope of protection of the present invention is not limited thereto.

[0072] In this invention, the leakage amount is measured according to the following method:

[0073] After the composite diaphragms obtained in the following examples and comparative examples were cut and processed, they were left to stand for 24 hours in an environment of 20°C and 60% humidity. Then, they were tested according to the leakage test in SY / T 0511-2010 8.6. The specific process is as follows: the composite diaphragms are installed on the valve discs of breather valves with different nominal diameters. The valve disc counterweight is 1350Pa. The breather valves are then installed on the breather valve test platform. The pressure is adjusted to 1012Pa (0.75 times the opening pressure). The leakage of the breather valve is measured. The value is recorded once every minute for a total of three times. The arithmetic mean is taken as the leakage of the breather valve of the storage tank when the pressure is not lower than 0.75 times the opening pressure (1012Pa).

[0074] In this invention, the fluororubber 246 was purchased from LG Corporation of South Korea and has a density of 1.5 g / cm³. 3 Tensile strength 450 kg / cm 2 The fluororubber 26 was purchased from Shandong Huaxia Shenzhou Company, and its physical parameters are 1.8 g / cm³. 3 Tensile strength 135 kg / cm 2 .

[0075] Example 1

[0076] (1) Preparation of fluororubber composite materials:

[0077] Fluororubber (10 kg of fluororubber 246), inorganic filler (6 kg of aluminum silicate), acid scavenger (1 kg of calcium oxide), vulcanizing agent (0.2 kg of N,N'-biscinnamaldehyde-1,6-hexanediamine), release agent (0.02 kg of zinc stearate), and colorant (0.3 kg of colloidal graphite) were added to a mixer and mixed at a speed of 60 rpm, a temperature of 60°C, and a time of 15 min. The resulting product was then refined 10 times with a roller gap of 0.2 mm and a roller temperature of 140°C to obtain a fluororubber composite material.

[0078] (2) Preparation of composite membranes:

[0079] Fluororubber composite material was spread on a 0.1 mm thick PEEK polymer sheet and thermally bonded at a temperature of 160 °C for 1 min to obtain a pre-cured composite film. The film was then vulcanized at 240 °C for 8 h to obtain a composite film A1 consisting of a 0.2 mm fluororubber composite material layer and a 0.1 mm PEEK polymer sheet layer.

[0080] After being left to stand, the composite diaphragm A1 is cut to obtain diaphragm 1a with a nominal diameter of 80 mm, diaphragm 1b with a nominal diameter of 100 mm, diaphragm 1c with a nominal diameter of 150 mm, diaphragm 1d with a nominal diameter of 200 mm, diaphragm 1e with a nominal diameter of 250 mm, and diaphragm 1f with a nominal diameter of 300 mm.

[0081] According to SY / T 0511-2010 8.6, the leakage of the above composite diaphragm was tested, and the results are shown in Table 1.

[0082] Table 1

[0083] Composite membrane number Breather valve nominal diameter / mm <![CDATA[Maximum leakage rate m 3 / h]]> 1a 80 0.0009 1b 100 0.0010 1c 150 0.0016 1d 200 0.0028 1e 250 0.0033 1f 300 0.0042

[0084] Example 2

[0085] (1) Preparation of fluororubber composite materials:

[0086] Fluororubber (10 kg of fluororubber 26), inorganic fillers (0.5 kg of silica, 0.3 kg of calcium silicate, 0.1 kg of magnesium silicate and 0.1 kg of boron nitride), acid scavenger (1 kg of magnesium oxide), vulcanizing agent (0.5 kg of N,N'-biscinnamaldehyde-1,6-hexanediamine), release agent (0.02 kg of paraffin wax), and colorant (0.2 kg of iron oxide red) were added to a mixer and mixed at a speed of 20 rpm, a temperature of 80°C, and a time of 60 min. The resulting product was then refined 20 times with a roller gap of 2 mm and a roller temperature of 100°C to obtain a fluororubber composite material.

[0087] (2) Preparation of composite membranes:

[0088] Fluororubber composite material is spread on a 0.5 mm thick PTFE polymer sheet and thermally bonded at a temperature of 150 °C for 10 min to obtain a pre-cured composite film. The film is then vulcanized at 180 °C for 24 h to obtain a composite film A2 consisting of a 2 mm fluororubber composite material layer and a 0.5 mm PTFE polymer sheet layer.

[0089] After being left to stand, the composite diaphragm A2 is cut to obtain diaphragm 2a with a nominal diameter of 80 mm and diaphragm 2b with a nominal diameter of 100 mm and diaphragm 2c with a nominal diameter of 150 mm and diaphragm 2d with a nominal diameter of 200 mm and diaphragm 2e with a nominal diameter of 250 mm and diaphragm 2f with a nominal diameter of 300 mm and diaphragm respectively.

[0090] According to SY / T 0511-2010 8.6, the leakage of the above composite diaphragm was tested, and the results are shown in Table 2.

[0091] Table 2

[0092] Composite membrane number Breather valve nominal diameter / mm <![CDATA[Maximum leakage rate m 3 / h]]> 2a 80 0.0009 2b 100 0.0013 2c 150 0.0011 2d 200 0.0020 2e 250 0.0033 2f 300 0.0040

[0093] Example 3

[0094] (1) Preparation of fluororubber composite materials:

[0095] Fluororubber (10 kg of fluororubber 246), inorganic fillers (1 kg of calcium carbonate, 1 kg of diatomaceous earth, 0.5 kg of calcium silicate, and 0.1 kg of graphite), acid absorber (1 kg of zinc oxide), vulcanizing agent (0.02 kg of benzyltriphenylphosphine chloride), mold release agent (0.02 kg of ammonium stearate), and colorant (0.03 kg of iron oxide red) were added to a mixer and mixed at a speed of 30 rpm, a temperature of 70°C, and a time of 40 min. The resulting product was then refined 30 times with a roller gap of 4 mm and a roller temperature of 120°C to obtain a fluororubber composite material.

[0096] (2) Preparation of composite membranes:

[0097] Fluororubber composite material is spread on a 1 mm thick PI polymer sheet and thermally bonded at a temperature of 150 °C for 5 min to obtain a pre-cured composite film. The film is then vulcanized at 200 °C for 16 h to obtain a composite film A3 consisting of a 4 mm fluororubber composite material layer and a 1 mm PI polymer sheet layer.

[0098] After being left to stand, the composite diaphragm A3 is cut to obtain diaphragms 3a (nominal diameter 80mm), 3b (nominal diameter 100mm), 3c (nominal diameter 150mm), 3d (nominal diameter 200mm), 3e (nominal diameter 250mm), and 3f (nominal diameter 300mm).

[0099] According to SY / T 0511-2010 8.6, the leakage of the above composite diaphragm was tested, and the results are shown in Table 3.

[0100] Table 3

[0101] Composite membrane number Breather valve nominal diameter / mm <![CDATA[Maximum leakage rate m 3 / h]]> 3a 80 0.0001 3b 100 0.0001 3c 150 0.0002 3d 200 0.0019 3e 250 0.0020 3f 300 0.0020

[0102] Example 4

[0103] (1) Preparation of fluororubber composite materials:

[0104] Fluororubber (10 kg of fluororubber 26), inorganic fillers (4 kg of aluminum silicate, 1 kg of barium sulfate, 0.05 kg of silicon nitride and 0.2 kg of graphite), acid scavenger (1 kg of calcium oxide and 0.5 kg of calcium hydroxide), vulcanizing agent (0.01 kg of dicumyl peroxide), release agent (0.02 kg of paraffin wax), and colorant (0.2 kg of iron oxide red) were added to a mixer and mixed at a speed of 40 rpm, a temperature of 65°C, and a time of 30 min. The resulting product was then refined 30 times with a roller gap of 0.5 mm and a roller temperature of 130°C to obtain a fluororubber composite material.

[0105] (2) Preparation of composite membranes:

[0106] Fluororubber composite material is laid on a 0.6 mm thick PTFE polymer sheet and thermally bonded at a temperature of 160 °C for 7 min to obtain a pre-cured composite film. The film is then vulcanized at 220 °C for 12 h to obtain a composite film A4 consisting of a 0.6 mm fluororubber composite material layer and a 0.6 mm PTFE polymer sheet layer.

[0107] After being left to stand, the composite diaphragm A4 is cut to obtain diaphragms 4a (nominal diameter 80mm), 4b (nominal diameter 100mm), 4c (nominal diameter 150mm), 4d (nominal diameter 200mm), 4e (nominal diameter 250mm), and 4f (nominal diameter 300mm).

[0108] According to SY / T 0511-2010 8.6, the leakage of the above composite diaphragm was tested, and the results are shown in Table 4.

[0109] Table 4

[0110] Composite membrane number Breather valve nominal diameter / mm <![CDATA[Maximum leakage rate m 3 / h]]> 4a 80 0.0010 4b 100 0.0011 4c 150 0.0010 4d 200 0.0026 4e 250 0.0029 4f 300 0.0040

[0111] Example 5

[0112] (1) Preparation of fluororubber composite materials:

[0113] Fluororubber (10 kg of fluororubber 246), inorganic fillers (1 kg of calcium silicate, 1 kg of magnesium silicate, 0.5 kg of calcium carbonate and 0.1 kg of graphite), acid scavenger (0.5 kg of calcium oxide and 0.5 kg of calcium hydroxide), vulcanizing agent (0.01 kg of 2,5-dimethyl-2,5-di-tert-butylperoxide), vulcanization accelerator (0.01 kg of triallyl isocyanurate), release agent (0.01 kg of paraffin wax), and colorant (0.15 kg of iron oxide red) were added to a mixer and mixed at a speed of 50 rpm, a temperature of 70°C, and a time of 30 min. The resulting product was then refined 30 times with a roller gap of 1 mm and a roller temperature of 140°C to obtain a fluororubber composite material.

[0114] (2) Preparation of composite membranes:

[0115] Fluororubber composite material is spread on a 0.5 mm thick PTFE polymer sheet and thermally bonded at a temperature of 160 °C for 10 min to obtain a pre-cured composite film. The film is then vulcanized at 240 °C for 16 h to obtain a composite film A5 consisting of a 2 mm fluororubber composite material layer and a 0.5 mm PTFE polymer sheet layer.

[0116] After being left to stand, the composite diaphragm A5 is cut to obtain diaphragms 5a (nominal diameter 80mm), 5b (nominal diameter 100mm), 5c (nominal diameter 150mm), 5d (nominal diameter 200mm), 5e (nominal diameter 250mm), and 5f (nominal diameter 300mm).

[0117] According to SY / T 0511-2010 8.6, the leakage of the above composite diaphragm was tested, and the results are shown in Table 5.

[0118] Table 5

[0119] Composite membrane number Breather valve nominal diameter / mm <![CDATA[Maximum leakage rate m 3 / h]]> 5a 80 0.0001 5b 100 0.0002 5c 150 0.0001 5d 200 0.0002 5e 250 0.0006 5f 300 0.0016

[0120] Example 6

[0121] The method was implemented according to Example 5, except that the inorganic filler consisted of 0.5 kg of silica, 1 kg of silicon nitride, and 1.1 kg of boron nitride. The specific operation was as follows:

[0122] (1) Preparation of fluororubber composite materials:

[0123] Fluororubber (10 kg of fluororubber 246), inorganic fillers (0.5 kg of silica, 1 kg of silicon nitride and 1 kg of boron nitride), acid scavenger (0.5 kg of calcium oxide and 0.5 kg of calcium hydroxide), vulcanizing agent (0.01 kg of 2,5-dimethyl-2,5-di-tert-butylperoxide), vulcanization accelerator (0.01 kg of triallyl isocyanurate), release agent (0.01 kg of paraffin wax), and colorant (0.15 kg of iron oxide red) were added to a mixer and mixed at a speed of 50 rpm, a temperature of 70°C, and a time of 30 min. The resulting product was then refined 30 times with a roller gap of 1 mm and a roller temperature of 140°C to obtain a fluororubber composite material.

[0124] (2) Preparation of composite membranes:

[0125] Fluororubber composite material is laid on a 0.5 mm thick PTFE polymer sheet and thermally bonded at a temperature of 160 °C for 10 min to obtain a pre-cured composite film. The film is then vulcanized at 240 °C for 16 h to obtain a composite film A6 consisting of a 1 mm fluororubber composite material layer and a 0.5 mm PTFE polymer sheet layer.

[0126] After being left to stand, the composite diaphragm A6 is cut to produce diaphragms 6a (nominal diameter 80mm), 6b (nominal diameter 100mm), 6c (nominal diameter 150mm), 6d (nominal diameter 200mm), 6e (nominal diameter 250mm), and 6f (nominal diameter 300mm).

[0127] According to SY / T 0511-2010 8.6, the leakage of the above composite diaphragm was tested, and the results are shown in Table 6.

[0128] Table 6

[0129]

[0130]

[0131] Example 7

[0132] The method was implemented according to Example 5, except that the inorganic filler consisted of 1 kg of aluminum silicate and 1.6 kg of diatomaceous earth. The specific operation was as follows:

[0133] (1) Preparation of fluororubber composite materials:

[0134] Fluororubber (10 kg of fluororubber 246), inorganic fillers (1 kg of aluminum silicate and 1.6 kg of diatomaceous earth), acid absorbent (0.5 kg of calcium oxide and 0.5 kg of calcium hydroxide), vulcanizing agent (0.01 kg of 2,5-dimethyl-2,5-di-tert-butylperoxide), vulcanization accelerator (0.01 kg of triallyl isocyanurate), release agent (0.01 kg of paraffin wax), and colorant (0.15 kg of iron oxide red) were added to a mixer and mixed at a speed of 50 rpm, a temperature of 70°C, and a time of 30 min. The resulting product was then refined 30 times with a roller gap of 1 mm and a roller temperature of 140°C to obtain a fluororubber composite material.

[0135] (2) Preparation of composite membranes:

[0136] Fluororubber composite material is spread on a 0.5 mm thick PTFE polymer sheet and thermally bonded at a temperature of 160 °C for 10 min to obtain a pre-cured composite film. The film is then vulcanized at 240 °C for 16 h to obtain a composite film A7 consisting of a 1 mm fluororubber composite material layer and a 0.5 mm PTFE polymer sheet layer.

[0137] After being left to stand, the composite diaphragm A7 is cut to produce diaphragms 7a (nominal diameter 80mm), 7b (nominal diameter 100mm), 7c (nominal diameter 150mm), 7d (nominal diameter 200mm), 7e (nominal diameter 250mm), and 7f (nominal diameter 300mm).

[0138] According to SY / T 0511-2010 8.6, the leakage of the above composite diaphragm was tested, and the results are shown in Table 7.

[0139] Table 7

[0140] Composite membrane number Breather valve nominal diameter / mm <![CDATA[Maximum leakage rate m 3 / h]]> 7a 80 0.0005 7b 100 0.0007 7c 150 0.0008 7d 200 0.0018 7e 250 0.0017 7f 300 0.0026

[0141] Example 8

[0142] The method described in Example 5 was followed, except that no vulcanization accelerator was added. The specific operation was as follows:

[0143] (1) Preparation of fluororubber composite materials:

[0144] Fluororubber (10 kg of fluororubber 246), inorganic fillers (1 kg of calcium silicate, 1 kg of magnesium silicate, 0.5 kg of calcium carbonate and 0.1 kg of graphite), acid scavenger (0.5 kg of calcium oxide and 0.5 kg of calcium hydroxide), vulcanizing agent (0.01 kg of 2,5-dimethyl-2,5-di-tert-butylperoxide), release agent (0.01 kg of paraffin wax), and colorant (0.15 kg of iron oxide red) were added to a mixer and mixed at a speed of 50 rpm, a temperature of 70°C, and a time of 30 min. The resulting product was then refined 30 times with a roller gap of 1 mm and a roller temperature of 140°C to obtain a fluororubber composite material.

[0145] (2) Preparation of composite membranes:

[0146] Fluororubber composite material is spread on a 0.5 mm thick PTFE polymer sheet and thermally bonded at a temperature of 160 °C for 10 min to obtain a pre-cured composite film. The film is then vulcanized at 240 °C for 16 h to obtain a composite film A8 consisting of a 1 mm fluororubber composite material layer and a 0.5 mm PTFE polymer sheet layer.

[0147] After being left to stand, the composite diaphragm A8 is cut to produce diaphragms 8a (nominal diameter 80mm), 8b (nominal diameter 100mm), 8c (nominal diameter 150mm), 8d (nominal diameter 200mm), 8e (nominal diameter 250mm), and 8f (nominal diameter 300mm).

[0148] According to SY / T 0511-2010 8.6, the leakage of the above composite diaphragm was tested, and the results are shown in Table 8.

[0149] Table 8

[0150] Composite membrane number Breather valve nominal diameter / mm <![CDATA[Maximum leakage rate m 3 / h]]> 8a 80 0.0011 8b 100 0.0013 8c 150 0.0013 8d 200 0.0029 8e 250 0.0033 8f 300 0.0038

[0151] Example 9

[0152] The method described in Example 5 is followed, except that the vulcanization temperature is 190°C. The specific operation is as follows:

[0153] (1) Preparation of fluororubber composite materials:

[0154] Fluororubber (10 kg of fluororubber 246), inorganic fillers (1 kg of calcium silicate, 1 kg of magnesium silicate, 0.5 kg of calcium carbonate and 0.1 kg of graphite), acid scavenger (0.5 kg of calcium oxide and 0.5 kg of calcium hydroxide), vulcanizing agent (0.01 kg of 2,5-dimethyl-2,5-di-tert-butylperoxide), vulcanization accelerator (0.01 kg of triallyl isocyanurate), release agent (0.01 kg of paraffin wax), and colorant (0.15 kg of iron oxide red) were added to a mixer and mixed at a speed of 50 rpm, a temperature of 70°C, and a time of 30 min. The resulting product was then refined 30 times with a roller gap of 1 mm and a roller temperature of 140°C to obtain a fluororubber composite material.

[0155] (2) Preparation of composite membranes:

[0156] Fluororubber composite material is spread on a 0.5 mm thick PTFE polymer sheet and thermally bonded at a temperature of 160 °C for 10 min to obtain a pre-cured composite film. The film is then vulcanized at 190 °C for 16 h to obtain a composite film A9 consisting of a 1 mm fluororubber composite material layer and a 0.5 mm PTFE polymer sheet layer.

[0157] After being left to stand, the composite diaphragm A9 is cut to obtain diaphragms 9a (nominal diameter 80mm), 9b (nominal diameter 100mm), 9c (nominal diameter 150mm), 9d (nominal diameter 200mm), 9e (nominal diameter 250mm), and 9f (nominal diameter 300mm).

[0158] According to SY / T 0511-2010 8.6, the leakage of the above composite diaphragm was tested, and the results are shown in Table 9.

[0159] Table 9

[0160] Composite membrane number Breather valve nominal diameter / mm <![CDATA[Maximum leakage rate m 3 / h]]> 9a 80 0.0002 9b 100 0.0004 9c 150 0.0005 9d 200 0.0010 9e 250 0.0022 9f 300 0.0030

[0161] Example 10

[0162] The method described in Example 5 was followed, except that the thickness of the PTFE polymer sheet was 0.8 mm. The specific operation was as follows:

[0163] (1) Preparation of fluororubber composite materials:

[0164] Fluororubber (10 kg of fluororubber 246), inorganic fillers (1 kg of calcium silicate, 1 kg of magnesium silicate, 0.5 kg of calcium carbonate and 0.1 kg of graphite), acid scavenger (0.5 kg of calcium oxide and 0.5 kg of calcium hydroxide), vulcanizing agent (0.01 kg of 2,5-dimethyl-2,5-di-tert-butylperoxide), vulcanization accelerator (0.01 kg of triallyl isocyanurate), release agent (0.01 kg of paraffin wax), and colorant (0.15 kg of iron oxide red) were added to a mixer and mixed at a speed of 50 rpm, a temperature of 70°C, and a time of 30 min. The resulting product was then refined 30 times with a roller gap of 1 mm and a roller temperature of 140°C to obtain a fluororubber composite material.

[0165] (2) Preparation of composite membranes:

[0166] Fluororubber composite material is spread on a 0.8 mm thick PTFE polymer sheet and thermally bonded at a temperature of 160 °C for 10 min to obtain a pre-cured composite film. The film is then vulcanized at 240 °C for 16 h to obtain a composite film A10 consisting of a 1 mm fluororubber composite material layer and a 0.8 mm PTFE polymer sheet layer.

[0167] After being left to stand, the composite diaphragm A10 is cut to produce diaphragms 10a (nominal diameter 80mm), 10b (nominal diameter 100mm), 10c (nominal diameter 150mm), 10d (nominal diameter 200mm), 10e (nominal diameter 250mm), and 10f (nominal diameter 300mm).

[0168] According to SY / T 0511-2010 8.6, the leakage of the above composite diaphragm was tested, and the results are shown in Table 10.

[0169] Table 10

[0170] Composite membrane number Breather valve nominal diameter / mm <![CDATA[Maximum leakage rate m 3 / h]]> 10a 80 0.0005 10b 100 0.0009 10c 150 0.0010 10d 200 0.0023 10e 250 0.0026 10f 300 0.0040

[0171] Comparative Example 1

[0172] The method described in Example 5 was followed, except that the thickness of the PTFE polymer sheet was 1.5 mm. The specific operation was as follows:

[0173] (1) Preparation of fluororubber composite materials:

[0174] Fluororubber (10 kg of fluororubber 246), inorganic fillers (1 kg of calcium silicate, 1 kg of magnesium silicate, 0.5 kg of calcium carbonate and 0.1 kg of graphite), acid scavenger (0.5 kg of calcium oxide and 0.5 kg of calcium hydroxide), vulcanizing agent (0.01 kg of 2,5-dimethyl-2,5-di-tert-butylperoxide), vulcanization accelerator (0.01 kg of triallyl isocyanurate), release agent (0.01 kg of paraffin wax), and colorant (0.15 kg of iron oxide red) were added to a mixer and mixed at a speed of 50 rpm, a temperature of 70°C, and a time of 30 min. The resulting product was then refined 30 times with a roller gap of 1 mm and a roller temperature of 140°C to obtain a fluororubber composite material.

[0175] (2) Preparation of composite membranes:

[0176] Fluororubber composite material was spread on a 1.5 mm thick PTFE polymer sheet and thermally bonded at a temperature of 160 °C for 10 min to obtain a pre-cured composite film. The film was then vulcanized at 240 °C for 16 h to obtain a composite film B1 consisting of a 2 mm fluororubber composite material layer and a 1.5 mm PTFE polymer sheet layer.

[0177] After being left to stand, the composite diaphragm B1 is cut to produce diaphragms B1a (nominal diameter 80mm), B1b (nominal diameter 100mm), B1c (nominal diameter 150mm), B1d (nominal diameter 200mm), B1e (nominal diameter 250mm), and B1f (nominal diameter 300mm).

[0178] According to SY / T 0511-2010 8.6, the leakage of the above composite diaphragm was tested, and the results are shown in Table 11.

[0179] Table 11

[0180]

[0181]

[0182] Comparative Example 2

[0183] The method described in Example 5 was followed, except that nitrile rubber (purchased from LG Corporation, Korea, grade LG B3250) was used instead of fluororubber. The specific operation was as follows:

[0184] (1) Preparation of nitrile rubber composite material:

[0185] Nitrile rubber (10 kg), inorganic fillers (1 kg calcium silicate, 1 kg magnesium silicate, 0.5 kg calcium carbonate and 0.1 kg graphite), acid scavenger (0.5 kg calcium oxide and 0.5 kg calcium hydroxide), vulcanizing agent (0.01 kg 2,5-dimethyl-2,5-di-tert-butylperoxide), vulcanization accelerator (0.01 kg triallyl isocyanurate), release agent (0.01 kg paraffin wax), and colorant (0.15 kg iron oxide red) were added to a mixer and mixed at a speed of 50 rpm, a temperature of 70°C, and a time of 30 min. The resulting product was then refined 30 times with a roller gap of 1 mm and a roller temperature of 140°C to obtain a nitrile rubber composite material.

[0186] (2) Preparation of composite membranes:

[0187] The nitrile rubber composite material was laid on a 0.5 mm thick PTFE polymer sheet and thermally bonded at a temperature of 160 °C for 10 min to obtain a pre-cured composite film. The film was then vulcanized at 240 °C for 16 h to obtain a composite film B2 consisting of a 2 mm nitrile rubber composite material layer and a 0.5 mm PTFE polymer sheet layer.

[0188] After being left to stand, the composite diaphragm B2 is cut to produce diaphragms B2a (nominal diameter 80mm), B2b (nominal diameter 100mm), B2c (nominal diameter 150mm), B2d (nominal diameter 200mm), B2e (nominal diameter 250mm), and B2f (nominal diameter 300mm).

[0189] According to SY / T 0511-2010 8.6, the leakage of the above composite diaphragm was tested, and the results are shown in Table 12.

[0190] Table 12

[0191] Composite membrane number Breather valve nominal diameter / mm <![CDATA[Maximum leakage rate m 3 / h]]> B2a 80 0.0330 B2b 100 0.0593 B2C 150 0.0815 B2d 200 0.1664 B2e 250 0.1749 B2f 300 0.2598

[0192] As can be seen from the results in Table 1-12, the composite diaphragms prepared in Examples 1-10, when used in breather valves with a nominal diameter of 150 mm or less, exhibit leakage as low as 0.0001–0.0016 m³ at a temperature of 20°C and 0.75 times the opening pressure of the tank breather valve. 3 Composite diaphragms used in breather valves with a nominal diameter of 200 mm and above exhibit leakage rates as low as 0.0002–0.0042 m³ / s at a temperature of 20°C and 0.75 times the opening pressure of the tank breather valve. 3The composite diaphragms prepared in Comparative Examples 1-2, when used in breather valves with a nominal diameter of 150 mm or less, exhibited a leakage rate of 0.0330–0.6829 m³ / s at 20°C and 0.75 times the opening pressure of the tank breather valve. 3 When used in breather valves with a nominal diameter of 200 mm or larger, at a temperature of 20°C and a pressure 0.75 times the opening pressure of the tank breather valve, the leakage rate is 0.1664–1.6484 m³ / s. 3 It is evident that the composite diaphragm obtained using the technical solution described in this invention significantly reduces the leakage of the breather valve from 0.75 times the opening pressure to below the opening pressure.

[0193] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A low-leakage breather valve composite diaphragm, characterized in that, The composite membrane comprises a polymer sheet layer and a fluororubber composite material layer. The thickness of the polymer sheet is 0.1~1mm; The thickness ratio of the polymer sheet to the fluororubber composite layer is 1:1 to 4; The fluororubber composite material layer is made from a raw material composition containing fluororubber, inorganic filler, acid absorber, vulcanizing agent, release agent and colorant; The polymer sheet forming the polymer layer is selected from one or more of polyetheretherketone, polytetrafluoroethylene, and polyimide.

2. The composite membrane according to claim 1, characterized in that, In the raw material composition, the fluororubber is type 26 fluororubber or type 246 fluororubber.

3. The composite membrane according to claim 1 or 2, characterized in that, In the raw material composition, the inorganic filler is selected from one or more of the following: silica, calcium silicate, magnesium silicate, aluminum silicate, calcium carbonate, barium sulfate, diatomaceous earth, graphite, silicon nitride, and boron nitride.

4. The composite membrane according to claim 1 or 2, characterized in that, In the raw material composition, the acid absorbent is selected from one or more of magnesium oxide, calcium oxide, zinc oxide and calcium hydroxide.

5. The composite membrane according to claim 1 or 2, characterized in that, In the raw material composition, the vulcanizing agent is selected from one or more of N,N'-biscinnamaldehyde-1,6-hexanediamine, 2,2-(4-hydroxyphenyl)hexafluoropropane, dicumyl peroxide and 2,5-dimethyl-2,5-ditert-butylperoxide.

6. The composite membrane according to claim 1 or 2, characterized in that, In the raw material composition, the release agent is selected from one or more of zinc stearate, ammonium stearate and paraffin wax.

7. The composite membrane according to claim 1 or 2, characterized in that, In the raw material composition, the colorant is selected from one or more of iron oxide red, colloidal graphite and carbon black.

8. The composite membrane according to claim 1 or 2, characterized in that, In the raw material composition, the weight ratio of the fluororubber, the inorganic filler, the acid absorber, the vulcanizing agent, the mold release agent and the colorant is 100:10~60:0.001~20:0.001~5:0.2~2:0.001~3.

9. The composite membrane according to claim 1, characterized in that, The raw material composition also contains a vulcanization accelerator.

10. The composite membrane according to claim 9, characterized in that, The weight ratio of the fluororubber to the vulcanization accelerator is 100:0.001~2.

11. The composite membrane according to claim 9, characterized in that, The vulcanization accelerator is triallyl isocyanurate.

12. A method for preparing the low-leakage breather valve composite diaphragm according to any one of claims 1-11, characterized in that, The method includes: (1) Preparation of fluororubber composite material: The raw material composition is mixed and then the resulting product is refined multiple times to obtain fluororubber composite material; (2) Preparation of composite membranes: The polymer sheet and the fluororubber composite material are thermally bonded together and then vulcanized to obtain a composite film.

13. The method according to claim 12, characterized in that, In step (1), the mixing conditions include: temperature of 50~80℃, time of 15~60min, and rotation speed of 20~60 rpm.

14. The method according to claim 12 or 13, characterized in that, In step (1), the refining conditions include: a temperature of 100~140℃, a refining cycle of 10~30 times, and a roller gap of 0.2~4mm.

15. The method according to claim 12, characterized in that, In step (2), the conditions for thermal bonding include: a temperature of 150~160℃ and a time of 1~10min.

16. The method according to claim 12, characterized in that, In step (2), the vulcanization conditions include a temperature of 180~240℃ and a time of 8~24h.

17. A low-leakage breather valve composite diaphragm prepared by the method according to any one of claims 12-16.

18. The use of the composite diaphragm according to any one of claims 1-11 or the composite diaphragm according to claim 17 as a sealing material for a breather valve.

Images