Functional gradient perfluoroether rubber material as well as preparation method and application thereof

Abstract

The invention discloses a functionally gradient perfluoroether rubber material as well as a preparation method and application thereof. The functional gradient perfluoroether rubber material comprises a contact layer, a transition layer and a supporting layer which are tightly connected in sequence, wherein the contact layer is prepared from raw materials including raw perfluoroether rubber, a filling agent, a vulcanizing agent and a plasticizer; the transition layer is prepared from raw materials including raw perfluoroether rubber, a filling agent and a vulcanizing agent; the supporting layer is prepared from raw materials including raw perfluoroether rubber, a filling agent and a vulcanizing agent; the Shore A hardness of the contact layer is smaller than or equal to the Shore A hardness of the transition layer and smaller than or equal to the Shore A hardness of the supporting layer. Through component gradient design and process regulation and control, continuous gradient distribution of mechanical properties such as hardness and viscoelasticity of the material in space is realized, so that the problem of contradiction between the sealing performance of the elastic membrane of the medical micro-flow electromagnetic valve and the pipetting precision is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and specifically to a functionally gradient perfluoroelastomer (FFKM) material, a preparation method, and applications thereof. The FFKM material is particularly suitable for elastic membrane components of medical micro-flow solenoid valves, and a gradient design is used to resolve the contradiction between sealing performance and pipetting accuracy. Background Art

[0002] Perfluoroether rubber (FFKM) is widely used in the sealing field due to its excellent chemical resistance and high-temperature stability. Since raw perfluoroether rubber cannot generally be used alone, current research focuses on modifying components such as vulcanizers, reinforcing fillers, and processing aids. In particular, to improve the mechanical properties of perfluoroether rubber materials, large amounts of carbon black or inorganic mineral fillers are generally added for reinforcement. Currently, companies such as DuPont, Daikin, Solvay, and 3M have all achieved the industrialization of FFKM. Furthermore, current patents focus primarily on applications in the semiconductor field, as well as perfluoroether rubber materials and their preparation methods for special application conditions such as high strength and high modulus, high temperature resistance, and low temperature resistance.

[0003] However, the inventors of the present invention found that traditional homogeneous perfluoroether rubber materials face the following problems in the elastic membrane components of medical micro-flow solenoid valves: the contradiction between sealing performance and pipetting accuracy: high-hardness materials have poor sealing but high pipetting accuracy, while low-hardness materials have good sealing but low accuracy; the conflict between interface adhesion and response time: large interface adhesion leads to prolonged response time of the solenoid valve, affecting pipetting accuracy; unstable performance in complex media environments: existing materials are difficult to take into account corrosion resistance, mechanical properties and dynamic sealing requirements.

[0004] Prior research on gradient design of elastic membranes is limited, and there is a lack of effective solutions for achieving functional zoning through microstructural regulation. Therefore, there is an urgent need to develop a functionally gradient perfluoroelastomer material that optimizes the synergistic effects of mechanical properties and interfacial behavior through a gradient distribution of components and structures. Summary of the Invention

[0005] The purpose of the present invention is to provide a functionally gradient perfluoroether rubber material and a preparation method. Through component gradient design and process control, a continuous gradient distribution of mechanical properties such as material hardness and viscoelasticity can be achieved in space, thereby resolving the contradiction between the sealing performance of the elastic membrane of medical micro-flow solenoid valves and the pipetting accuracy.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The first aspect of the present invention is to provide a functionally gradient perfluoroether rubber material, wherein the functionally gradient perfluoroether rubber material comprises a contact layer, a transition layer and a support layer tightly connected in sequence;

[0008] The contact layer is made of raw materials including perfluoroether rubber, filler, vulcanizer and plasticizer; the contact layer is the part of the elastic membrane assembly of the medical micro-flow solenoid valve that is in direct contact with the liquid;

[0009] The transition layer is made of raw materials including perfluoroether rubber, filler and vulcanizing agent;

[0010] The support layer is made of raw materials including perfluoroether rubber, filler and vulcanizing agent;

[0011] The Shore A hardness of the contact layer is less than or equal to the Shore A hardness of the transition layer and less than or equal to the Shore A hardness of the support layer.

[0012] As a preferred embodiment,

[0013] Taking the total weight of the raw materials of the contact layer as 100%;

[0014] The contact layer includes 84wt% to 92.5wt% of perfluoroether rubber (for example, 84wt%, 86wt%, 88wt%, 90wt%, 92wt%, 92.5wt%), 5wt% to 10wt% of filler (for example, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%), 0.5wt% to 3wt% of vulcanizer (for example, 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%) and 1wt% to 3wt% of plasticizer (for example, 1wt%, 1.25wt%, 1.5wt%, 1.75wt%, 2wt%, 2.25wt%, 2.5wt%, 2.75wt%, 3wt%).

[0015] As a preferred embodiment,

[0016] Taking the total weight of the raw materials of the transition layer as 100%;

[0017] The transition layer includes 76wt% to 83wt% of perfluoroether rubber raw rubber (for example, 76wt%, 77wt%, 78wt%, 79wt%, 80wt%, 81wt%, 82wt%, 83wt%), 15wt% to 20wt% of filler (for example, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt%) and 2wt% to 4wt% of vulcanizing agent (for example, 2wt%, 2.25wt%, 2.5wt%, 2.75wt%, 3wt%, 3.25wt%, 3.5wt%, 3.75wt%, 4wt%).

[0018] As a preferred embodiment,

[0019] Taking the total weight of the raw materials of the support layer as 100%;

[0020] The supporting layer includes 70wt% to 75wt% of perfluoroether rubber raw rubber (for example, 70wt%, 71wt%, 72wt%, 73wt%, 74wt%, 75wt%), 20wt% to 24wt% of filler (for example, 20wt%, 21wt%, 22wt%, 23wt%, 24wt%) and 1wt% to 6wt% of vulcanizing agent (for example, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%).

[0021] As a preferred embodiment,

[0022] The fillers in the contact layer, transition layer and support layer are the same or different and are independently selected from at least one of graphite, carbon nanotubes, graphene, metal powder, molybdenum disulfide, boron nitride, lead oxide, boron compound, fumed silica, polytetrafluoroethylene powder, silicon carbide and conductive carbon black; and / or,

[0023] The vulcanizing agents in the contact layer, transition layer and support layer are the same or different and are independently selected from at least one of a compound vulcanizing agent of 2,5-dimethyl-2,5-di-tert-butylhexane peroxide and triallyl isocyanurate, a compound vulcanizing agent of bis-2,4-diisopropylbenzene peroxide and TMPTMA, bisphenol AF or tert-butyl benzoyl peroxide; and / or,

[0024] Preferably, in the composite vulcanizing agent of 2,5-dimethyl-2,5-di-tert-butyl peroxide hexane and triallyl isocyanurate, the mass ratio of 2,5-dimethyl-2,5-di-tert-butyl peroxide hexane to triallyl isocyanurate is 2-3:1;

[0025] In the compound curing agent of bis-2,4-diisopropylbenzene peroxide and TMPTMA, the mass ratio of bis-2,4-diisopropylbenzene peroxide to TMPTMA is 4-6:1;

[0026] The plasticizer in the contact layer is selected from at least one of perfluoropolyether oil, fluorinated hydrocarbon oil, phenyl silicone oil, and tricresyl phosphate.

[0027] In the present invention,

[0028] Perfluoroether rubber is the main material, providing excellent chemical corrosion resistance (resistant to strong acids and organic solvents) and high temperature stability (long-term use temperature can reach 230°C).

[0029] Fillers: such as graphite, carbon nanotubes, etc.; can improve the hardness, modulus and wear resistance of the material.

[0030] Curing agent system: For example, a combination of bis-25 (2,5-dimethyl-2,5-di-tert-butyl peroxyhexane) and TAIC (triallyl isocyanurate) (1% to 5%). Bis-25 acts as a peroxide curing agent to provide crosslinking activity, while TAIC acts as a co-curing agent to improve crosslink density and heat resistance. A 2:1 mass ratio of bis-25 to TAIC is preferred to ensure a high cure rate and uniform crosslinking network.

[0031] Other additives: such as plasticizers. Plasticizers reduce the viscosity of the rubber compound and facilitate processing.

[0032] The filler content of the contact layer is less than the filler content of the transition layer and less than the filler content of the support layer.

[0033] As a preferred embodiment,

[0034] The hardness of the contact layer is less than that of the transition layer, and the difference in Shore A hardness between the contact layer and the transition layer is ≤20;

[0035] The hardness of the transition layer is less than that of the support layer, and the Shore A hardness difference between the transition layer and the support layer is ≤20.

[0036] As a preferred embodiment,

[0037] The Shore A hardness of the contact layer is 50-60; for example, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60;

[0038] The Shore A hardness of the transition layer is 60 to 80; for example, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80;

[0039] The Shore A hardness of the support layer is 80-90, for example, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90.

[0040] The hardness of the material in the present invention gradually increases along the contact layer, transition layer, and support layer. The contact layer has a Shore A hardness of 50 to 60 and has high viscoelasticity, which improves the fit with the sealing surface and reduces the risk of interface leakage.

[0041] Transition layer: Shore A hardness: 60-80, with balanced sealing and mechanical support to avoid stress concentration;

[0042] The support layer has a Shore A hardness of 80-90 and a high modulus, ensuring the stability of the cavity size and shortening the solenoid valve response time (≤10ms).

[0043] The second aspect of the present invention is to provide a method for preparing the functionally gradient perfluoroether rubber material as described in the first aspect of the present invention, comprising the following steps:

[0044] (1) Mixing and kneading raw materials including perfluoroether rubber, filler, vulcanizing agent and plasticizer to prepare a contact layer;

[0045] (2) mixing and kneading raw materials including perfluoroether rubber, filler and vulcanizing agent to prepare a transition layer;

[0046] (3) mixing and kneading raw materials including perfluoroether rubber, filler and vulcanizing agent to prepare a support layer;

[0047] (4) After stacking in the order of support layer (support layer is at the bottom layer) → transition layer → contact layer, compression treatment is performed;

[0048] (5) Vulcanization molding.

[0049] As a preferred embodiment,

[0050] Step (1), the temperature of the blending and kneading is 80-90° C. and the time is 10-15 minutes; and / or,

[0051] Step (2), the temperature of the blending and kneading is 90-105°C and the time is 15-25 minutes; and / or,

[0052] Step (3), the temperature of blending and kneading is 110-120° C., and the time is 20-30 minutes.

[0053] As a preferred embodiment,

[0054] The present invention stacks rubber materials of different hardness in order on an open rubber mixer, and undergoes compression treatment (i.e., thin-pass treatment, roller spacing of 0.05 to 0.2 mm: initial roller spacing of 0.5 mm, gradually compressed to 0.05 mm, and shear force is used to promote entanglement of molecular chains between layers; the number of thin-pass treatments is ≥5 times to ensure that there are no bubbles and no stratification at the interface), so that the rubber layers of different hardness are turned into thinner layers to form a continuous gradient structure. The layers are stacked in the order of support layer → transition layer → contact layer. After the compression treatment, the layer thickness ratio of the contact layer, transition layer and support layer is 1:2:1, and the thickness of each layer is 0.2 to 0.5 mm; the thin-pass treatment (roller spacing of 0.05 to 0.2 mm) allows the molecular chains of adjacent layers of rubber to penetrate each other, forming a chemically bonded interface, thereby avoiding interface peeling due to sudden change in modulus (measured interface bonding strength ≥5 MPa); and / or,

[0055] A flat vulcanizing machine is used for two-stage vulcanization: the temperature of the first stage vulcanization is 160-180°C, the pressure is 10-15MPa, and the time is 10-20 minutes; the purpose is to achieve preliminary cross-linking, set the macro structure of the material, and avoid interlayer displacement; the temperature of the second stage vulcanization is 200-230°C, the pressure is normal pressure, and the time is 2-4 hours; the purpose is to achieve deep cross-linking, eliminate residual stress, and improve heat resistance (Tg≥-10°C) and media resistance.

[0056] The third aspect of the present invention is to provide an application of the functionally gradient perfluoroether rubber material as described in the first aspect of the present invention as an elastic membrane component of a medical micro-flow solenoid valve.

[0057] Compared with the prior art, the functionally gradient perfluoroelastomer material created by the present invention has the following advantages:

[0058] 1. Spatial regulation of mechanical properties is achieved through multi-layer component differentiation. Functionally graded design achieves improved sealing performance with a low-hardness contact layer and guaranteed pipetting accuracy with a high-hardness support layer, resolving the conflict between elastic membrane sealing performance and pipetting accuracy in medical micro-flow solenoid valves.

[0059] 2. The combination of thin-walled and segmented vulcanization ensures seamless gradient interface; the interface between gradient layers has strong bonding strength, avoiding delamination failure during use and effectively extending service life;

[0060] 3. Designed specifically for medical micro-flow solenoid valves, it balances sealing, precision, and longevity. It offers excellent chemical resistance and is suitable for use in complex media environments such as medical blood simulants, organic solvents, and strong acids. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 Schematic diagram of the layered structure of functionally graded perfluoroether rubber material;

[0062] Figure 2 Schematic diagram of the hardness distribution curve of gradient material. DETAILED DESCRIPTION

[0063] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0064] Example 1

[0065] Preparation of functionally graded perfluoroether rubber material, including contact layer, transition layer and support layer:

[0066] Contact layer: 100 parts of perfluoroether rubber, 10 parts of graphite, 1.5 parts of vulcanizing agent (bis-25 and TAIC mass ratio of 2:1), 2 parts of plasticizer (perfluoropolyether oil); the above materials are blended and kneaded at 85°C for 15 minutes to prepare the contact layer;

[0067] Transition layer: 100 parts of perfluoroether rubber, 20 parts of graphite, and 2.5 parts of vulcanizing agent (bis-25 and TAIC mass ratio of 2:1); the above raw materials are blended and kneaded at a temperature of 100°C and a time of 20 minutes to prepare the transition layer;

[0068] Support layer: 100 parts of perfluoroether rubber raw rubber, 30 parts of graphite, and 3.5 parts of vulcanizing agent (the mass ratio of double 25 to TAIC is 2:1); the above raw materials are blended and kneaded to prepare the support layer; wherein, the blending and kneading temperature is 115°C and the time is 25 minutes.

[0069] The Shore A hardness of each layer of material prepared by the above method is: (support layer) is 90 → (transition layer) is 70 → (contact layer) is 50. Figure 1 As shown, the support layer → transition layer → contact layer are stacked in order and compressed (i.e., thin-through treatment). After compression treatment, the thickness of the contact layer is 0.2 mm; the thickness of the transition layer is 0.4 mm; the thickness of the support layer is 0.2 mm; each layer is tightly connected, and then two-stage vulcanization is performed using a flat vulcanizer: the temperature of the first stage is 170°C, the pressure is 10 MPa, and the time is 15 minutes; the temperature of the second stage is 220°C, the pressure is normal pressure, and the time is 3 hours, to obtain the functionally gradient perfluoroether rubber material, which realizes a continuous gradient distribution of the material hardness in space, as shown in the schematic diagram. Figure 2 shown.

[0070] The functionally gradient perfluoroelastomer material prepared above was used as an elastic membrane component for a medical micro-flow solenoid valve to perform performance tests. The test results are as follows:

[0071] The interface bonding strength of the contact layer, transition layer and support layer is ≥5MPa (interface bonding strength is the bonding strength between the three layers of the material itself), and acid and alkali resistance (volume change rate after immersion for 72 hours is ≤0.3%).

[0072] Hardness gradient of the contact layer, transition layer, and support layer: 50→70→90 (layer thickness ratio 1:2:1); dynamic sealing: leakage rate ≤ 0.01μL / min (pressure difference 0.5MPa); the material showed no delamination failure after more than 100,000 cycles;

[0073] Chemical resistance: After being immersed in blood-simulating fluid at 37°C for 30 days, the volume expansion rate is 1.5%.

[0074] Cleanliness: The material was immersed in bovine serum albumin (1 mg / mL) at 37°C for 24 hours, and the adsorption capacity was determined by BCA method, ≤ 0.3 μg / cm 2 No migratable plasticizer or vulcanizing agent residues were detected (detection limit ≤ 0.1ppm).

[0075] Insulation: Volume resistivity ≥1.2×10 14 Ω·cm(25℃,50%RH);Surface resistivity(ASTM D257)≥1.5×10 13 Ω;

[0076] Solenoid valve response time ≤10ms;

[0077] The pipetting accuracy deviation is ±2%.

[0078] The above parameters prove that the functionally gradient perfluoroether rubber material prepared by the present invention can be used as an elastic membrane component of a medical micro-flow solenoid valve, taking into account sealing, precision and life; it has excellent chemical corrosion resistance and is suitable for complex media environments such as medical blood simulation fluid, organic solvents and strong acids.

[0079] Comparative Example 1

[0080] There are only contact layers and support layers; compression and vulcanization are then carried out under the same conditions as in Example 1.

[0081] The functionally gradient perfluoroelastomer material prepared above was used as an elastic membrane component for a medical micro-flow solenoid valve to perform performance tests. The test results are as follows:

[0082] Interface bonding strength ≥ 2MPa, acid and alkali resistance (volume change rate ≤ 0.3% after immersion for 72 hours).

[0083] Hardness gradient: 50→90 (layer thickness ratio 1:1);

[0084] Dynamic sealing: leakage rate ≤ 0.05μL / min (pressure difference 0.5MPa);

[0085] Chemical resistance: After immersion in 37°C blood-simulating fluid for 30 days, the volume expansion rate is ≤1.5%.

[0086] Cleanliness: The material was immersed in bovine serum albumin (1 mg / mL) at 37°C for 24 hours, and the adsorption capacity was determined by BCA method, ≤ 0.3 μg / cm 2 No migratable plasticizer or vulcanizing agent residues were detected (detection limit ≤ 0.1ppm).

[0087] Insulation: Volume resistivity ≥1.1×10 14 Ω·cm(25℃,50%RH);Surface resistivity(ASTM D257)≥1.5×10 13 Ω.

[0088] It can be seen from the results of Example 1 of the present invention and Comparative Example 1 that Comparative Example 1 has no transition layer, the leakage rate is increased, and the sealing performance is poor.

[0089] Comparative Example 2

[0090] Preparation of homogeneous perfluoroether rubber material (no gradient structure): Eliminate the component differences of the contact layer, transition layer, and support layer. The difference from Example 1 is that a single transition layer formula is used to prepare a homogeneous material, verifying the necessity of a gradient structure to resolve the contradiction between sealing and precision.

[0091] Performance test results

[0092] Hardness: Shore A 70 (evenly distributed).

[0093] Dynamic sealing: leakage rate ≥ 0.05 μL / min (pressure difference 0.5 MPa). Compared with Example 1, the leakage rate is at least 5 times higher. Since the material hardness is moderate, the sealing and precision are not optimized.

[0094] Interface bonding strength: There is no delamination problem, but the response time is ≥15ms (≤10ms in Example 1). Due to the lack of a high modulus support layer, the solenoid valve action is delayed.

[0095] Chemical resistance: The volume expansion rate after immersion in blood simulation liquid for 30 days is 1.8% (1.5% in Example 1). Due to the homogeneous structure, it is impossible to take into account both the medium resistance of the contact layer and the mechanical strength of the support layer.

[0096] Comparative Example 3

[0097] The functionally gradient perfluoroether rubber material has a gradient structure with an interlayer hardness difference of more than 20: the contact layer hardness is set to 40, the support layer hardness is set to 90, and the interlayer hardness difference is 50, which verifies the scientific nature of the present invention in controlling the interlayer hardness difference ≤ 20.

[0098] Preparation method

[0099] Hardness of each layer: contact layer Shore A40, transition layer Shore A60, support layer Shore A 90 (hardness difference between layers is 20 and 30 respectively).

[0100] The components were adjusted relative to those in Example 1: the plasticizer content in the contact layer was increased to 5%, and the filler content in the support layer was increased to 35%.

[0101] Performance test results

[0102] Interface bonding strength: 1.2 MPa (Example 1: ≥5 MPa). Due to the sudden change in modulus, the interface is easily peeled off, and microcracks are measured between the layers.

[0103] Dynamic sealing: Leakage rate 0.02 μL / min (pressure difference 0.5 MPa), but the material fails to delaminate after 5,000 cycles (Example 1 can be cycled more than 100,000 times).

[0104] Mechanical properties: The support layer became brittle and fractured during the bending test (the support layer of Example 1 had good flexibility), proving that excessively increasing the hardness would sacrifice the toughness of the material.

[0105] Conclusion: Necessity of gradient structure: By comparing the results of Examples 1 and 2 with those of Example 1, it can be proved that the lack of component gradient will lead to the inability to balance sealing performance and pipetting accuracy. The present invention achieves the synergistic optimization of sealing (leakage rate ≤ 0.01 μL / min) and accuracy (± 2%) through the gradient distribution of hardness from 50 → 70 → 90.

[0106] Interlayer matching: Comparison of the results of Example 3 and Example 1 shows that an interlayer hardness difference exceeding 20 will lead to a sudden drop in interface bonding strength (<3MPa), while the present invention controls the hardness difference to ≤20, ensuring that the interface bonding strength is ≥5MPa, thereby avoiding delamination failure.

[0107] In summary, the present invention realizes spatial continuous changes in hardness, modulus, and viscoelasticity through hardness gradient distribution and vulcanization process regulation; through the thin-through process combined with segmented vulcanization, the interlayer bonding strength reaches 5 to 8 MPa, far exceeding the traditional bonding process (≤3 MPa). The functional gradient perfluoroether rubber material prepared by the present invention takes into account sealing, precision, and life as an elastic membrane component of a medical micro-flow solenoid valve; it has excellent chemical corrosion resistance and is suitable for complex media environments such as medical blood simulation fluids, organic solvents, and strong acids. This design method can be extended to other functional gradient elastomers (such as silicone rubber and fluororubber) to meet high-end sealing needs in the fields of medical care, semiconductors, etc.

[0108] The above embodiments are provided for illustrative purposes only and are not intended to limit the scope of implementation. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to provide an exhaustive list of all implementations. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A functionally gradient perfluoroether rubber material, characterized in that: The functionally gradient perfluoroether rubber material comprises a contact layer, a transition layer and a support layer which are tightly connected in sequence; Wherein, the contact layer is made of raw materials including perfluoroether rubber, filler, vulcanizing agent and plasticizer; The transition layer is made of raw materials including perfluoroether rubber, filler and vulcanizing agent; The support layer is made of raw materials including perfluoroether rubber, filler and vulcanizing agent; The Shore A hardness of the contact layer is less than or equal to the Shore A hardness of the transition layer and less than or equal to the Shore A hardness of the support layer.

2. The functionally gradient perfluoroether rubber material according to claim 1, characterized in that: Taking the total weight of the raw materials of the contact layer as 100%; The contact layer comprises 84 wt% to 92.5 wt% of perfluoroether rubber, 5 wt% to 10 wt% of filler, 0.5 wt% to 3 wt% of vulcanizing agent and 1 wt% to 3 wt% of plasticizer.

3. The functionally gradient perfluoroether rubber material according to claim 1, characterized in that: Taking the total weight of the raw materials of the transition layer as 100%; The transition layer comprises 76 wt% to 83 wt% of perfluoroether rubber, 15 wt% to 20 wt% of a filler and 2 wt% to 4 wt% of a vulcanizing agent; and / or, Taking the total weight of the raw materials of the support layer as 100%; The support layer comprises 70 wt% to 75 wt% of perfluoroether rubber, 20 wt% to 24 wt% of a filler and 1 wt% to 6 wt% of a vulcanizing agent.

4. The functionally gradient perfluoroether rubber material according to claim 1, characterized in that: The fillers in the contact layer, transition layer and support layer are the same or different and are independently selected from at least one of graphite, carbon nanotubes, graphene, metal powder, molybdenum disulfide, boron nitride, lead oxide, boron compound, fumed silica, polytetrafluoroethylene powder, silicon carbide and conductive carbon black; and / or, The vulcanizing agents in the contact layer, transition layer and support layer are the same or different and are independently selected from at least one of a compound vulcanizing agent of 2,5-dimethyl-2,5-di-tert-butylhexane peroxide and triallyl isocyanurate, a compound vulcanizing agent of bis-2,4-diisopropylbenzene peroxide and TMPTMA, bisphenol AF or tert-butyl benzoyl peroxide; and / or, The plasticizer in the contact layer is selected from at least one of perfluoropolyether oil, fluorinated hydrocarbon oil, phenyl silicone oil, and tricresyl phosphate.

5. The functionally gradient perfluoroether rubber material according to claim 1, characterized in that: The hardness of the contact layer is less than that of the transition layer, and the difference in Shore A hardness between the contact layer and the transition layer is ≤20; The hardness of the transition layer is less than that of the support layer, and the Shore A hardness difference between the transition layer and the support layer is ≤20.

6. The functionally gradient perfluoroether rubber material according to claim 5, characterized in that: The Shore A hardness of the contact layer is 50 to 60; The Shore A hardness of the transition layer is 60 to 80; The Shore A hardness of the support layer is 80-90.

7. A method for preparing a functionally gradient perfluoroether rubber material according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) Mixing and kneading raw materials including perfluoroether rubber, filler, vulcanizing agent and plasticizer to prepare a contact layer; (2) mixing and kneading raw materials including perfluoroether rubber, filler and vulcanizing agent to prepare a transition layer; (3) mixing and kneading raw materials including perfluoroether rubber, filler and vulcanizing agent to prepare a support layer; (4) After stacking in the order of support layer → transition layer → contact layer, compression treatment is performed; (5) Vulcanization molding.

8. The method for preparing a functionally gradient perfluoroether rubber material according to claim 7, wherein: Step (1), the temperature of the blending and kneading is 80-90° C. and the time is 10-15 minutes; and / or, Step (2), the temperature of the blending and kneading is 90-105°C and the time is 15-25 minutes; and / or, Step (3), the temperature of blending and kneading is 110-120° C., and the time is 20-30 minutes.

9. The method for preparing a functionally gradient perfluoroether rubber material according to claim 8, wherein: A flat vulcanizing press is used for two-stage vulcanization: the temperature of the first stage vulcanization is 160-180°C, the pressure is 10-15 MPa, and the time is 10-20 minutes; the temperature of the second stage vulcanization is 200-230°C, the pressure is normal pressure, and the time is 2-4 hours.

10. Use of the functionally gradient perfluoroether rubber material according to any one of claims 1 to 6 as an elastic membrane component of a medical micro-flow solenoid valve.

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