A process for the preparation of an ethylene-propylene-vinylidene fluoride polymer and seals thereof

Abstract

The application provides a preparation method of an ethylene-propylene-vinylidene fluoride polymer and a seal thereof, and the preparation raw materials of the ethylene-propylene-vinylidene fluoride polymer comprise a polyethylene oligomer, a polypropylene oligomer, a hydroxyl fluorosilicone oil, polyvinylidene fluoride, an initiator and a terminator. The polyethylene oligomer, the polypropylene oligomer, the polyvinylidene fluoride and the hydroxyl fluorosilicone oil are subjected to silanization under the action of the initiator, and then the reaction is terminated by the terminator to prepare the ethylene-propylene-vinylidene fluoride polymer. Finally, the polymer is mixed with white carbon black A380, stearic acid, zinc oxide, a vulcanization accelerator TAIC, a vulcanizing agent double-25, an antioxidant 4010NA and a perfluoroether oil, and is subjected to vulcanization forming to obtain the ethylene-propylene-vinylidene fluoride polymer seal. The seal can obviously improve the low-temperature resistance, oil resistance and aging resistance of the product, and reduce the compression permanent deformation of the seal, and can be used for low-temperature oil-resistant special seals.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to an ethylene-propylene-vinylidene fluoride polymer seal and its preparation method. Background Technology

[0002] Vinylidene fluoride (PVDF) polymers have long been important materials in the field of specialty elastomers due to their excellent mechanical properties, superior oil resistance, and good temperature resistance. However, due to the limitations of their structure, PVDF polymers exhibit poor low-temperature performance. Copolymerization of ethylene with other functional monomers can effectively improve the low-temperature resistance of materials, but this requires high-temperature, high-pressure solution polymerization or emulsion polymerization. These technologies have high equipment requirements, leading to high polymerization technical difficulty and difficulty in reducing costs. Reactive grafting can improve the low-temperature resistance of PVDF polymers, but reactive grafting is limited by the reactive sites, resulting in poor product quality stability.

[0003] CN88100574.6 discloses a method for preparing a copolymer of vinylidene fluoride (VDF) and trifluorochloroethylene (TCFE). This method involves emulsion copolymerization or suspension copolymerization of VDF and TFE, characterized by a multiphase structure in which small spheres of a homogeneous copolymer of VDF and TFE are dispersed within a chemically bonded matrix formed by a VDF quasi-polymer. The copolymer is prepared through a two-stage suspension copolymerization or emulsion copolymerization, wherein one stage is the copolymerization of VDF and TFE, and the other stage is the polymerization of VDF. This invention utilizes the polymerization and phase distribution of the polymer in two stages to prepare a copolymer of VDF and TFE, thus reducing the reaction difficulty and simplifying the process.

[0004] CN201110422892.0 relates to a method for preparing polyvinylidene fluoride (PVDF) modified with trifluorochloroethylene. The method is characterized by first adding a mixture of gaseous monomers of PVDF and trifluorochloroethylene to an aqueous medium containing a fluorinated emulsifier to form a dispersion; then adding an initial amount of organic peroxide initiator and an initial amount of chain transfer agent to the dispersion to start the polymerization reaction, followed by intermittent addition of the remaining initiator and chain transfer agent in batches; finally, the reaction is stopped when the solid content of the emulsion in the reactor reaches 30%. This method provides specific steps for the trifluorochloroethylene-modified PVDF, offering an implementation method for future copolymerization of PVDF.

[0005] CN201810103782.X discloses methods for preparing poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) and poly(vinylidene fluoride-trifluoroethylene). Using N,N-dimethylformamide as a solvent, dyes or metal complexes as photosensitizers, and silane reagents as chain transfer agents, P(VDF-TrFE-CTFE) or P(VDF-TrFE) is synthesized in one step from P(VDF-CTFE). P(VDF-CTFE), the photosensitizer, and the chain transfer agent are simultaneously dissolved in a specific solvent. After stirring and reacting under specific light conditions for a certain time, the polymer precipitates in water. It is then repeatedly soaked and washed with methanol to remove unreacted organic matter and byproducts, and finally vacuum dried to constant weight. This method is simple, mild, and allows for controllable composition, easily yielding high-purity target products, and has excellent prospects for industrial application.

[0006] CN202211280300.0 relates to a vinylidene fluoride copolymer and a method for preparing the same. A vinylidene fluoride copolymer is provided, the copolymer comprising monomer units formed from vinylidene fluoride and a fluorinated acrylic compound represented by formula (1), wherein R-1, R-2, and R-3 are hydrogen, C-1 to C-(16) alkyl, or F, and at least one of them is F; R-4 is hydrogen, C-1 to C-(16) alkyl, C-1 to C-(16) fluoroalkyl, C-6 to C-(16) aryl, C-6 to C-(16) fluoroaryl, C-3 to C-(16) cycloalkyl, C-3 to C-(16) fluorocycloalkyl, alkali metal ion, ammonium ion, C-1 to C-(16) alkylammonium ion, or (C-1 to C-(16) alkyl)(C-6 to C-(16) aryl)ammonium ion. This invention covers most of the currently available vinylidene fluoride comonomers and has strong application value.

[0007] CN201310660130.3 discloses a vinylidene fluoride copolymer. It is produced by polymerizing vinylidene fluoride, tetrafluoroethylene, perfluorinated m-dioxane, or perfluorinated m-dioxane substituted with C1-4 alkoxy groups as raw materials in an emulsion composed of water, a fluorinated emulsifier, a chain transfer agent, a pH adjuster, and an antifouling agent, with an initiator added. The polymerization reaction occurs at 30-100°C and 2-7 MPa. The copolymer is then obtained through separation, purification, refining, coagulation, washing, drying, and granulation. The molar ratio of vinylidene fluoride, tetrafluoroethylene, and perfluorinated m-dioxane substituted with C1-4 alkoxy groups is 13-17:2-4:1-3. This vinylidene fluoride copolymer exhibits excellent transparency, flexibility, and solubility, and can be widely used in optical devices such as lenses; special membranes in solar panels and capacitors; fuel cell membranes; transparent and tough coatings; and large blown objects.

[0008] Existing technologies typically involve reducing reaction conditions through emulsion or solution polymerization, or adjusting the phase distribution of various polymers to prepare vinylidene fluoride (PVDF) polymers with good high-temperature resistance, oil resistance, and transparency. However, PVDF polymers prepared using existing technologies lose elasticity at low temperatures, ultimately leading to product hardening and functional failure. This invention utilizes the silanization mechanism of polyhydroxyfluorosilane with silica, polyolefins, and PVDF at high temperatures. Through silanization coupling of ethylene oligomers, propylene oligomers, hydroxyfluorosilicone oil, and PVDF under the action of an initiator, the ethylene-propylene-PVDF polymer is further terminated to obtain an ethylene-propylene-PVDF polymer. This invention solves the problems of poor low-temperature resistance, oil resistance, aging resistance, and compression set in existing PVDF polymer preparation technologies. The material can be used in low-temperature, oil-resistant special sealing components, and the technical route and preparation method have not been reported in the literature. Summary of the Invention

[0009] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing an ethylene-propylene-vinylidene fluoride polymer. In a reactive screw extruder and a closed rubber mixing mill, an initiator promotes the silanization of ethylene oligomers, propylene oligomers, polyvinylidene fluoride, and other polymers. After complete silanization, a terminator terminates the reaction, preparing the ethylene-propylene-vinylidene fluoride polymer. Finally, through compounding and vulcanization molding, a low-temperature and oil-resistant special sealing component is prepared. This invention improves the low-temperature resistance, oil resistance, and aging resistance of the product, and effectively reduces the compression set of the product.

[0010] To achieve this objective, the present invention adopts the following technical solution:

[0011] In a first aspect, the present invention provides a method for preparing an ethylene-propylene-vinylidene fluoride polymer and its sealing components, wherein the raw materials for preparing the ethylene-propylene-vinylidene fluoride polymer include, by weight: 15-50 (preferably 20-40) parts of polyethylene oligomer, 8-35 (preferably 10-30) parts of polypropylene oligomer, 3-15 (preferably 5-9) parts of hydroxyl fluorosilicone oil, 15-70 (preferably 30-50) parts of polyvinylidene fluoride, 0.05-0.20 parts of initiator and 0.5-2.0 parts of terminator.

[0012] The "low temperature resistance" mentioned in this invention refers to a temperature range of -20 to -60°C, such as -20°C, -30°C, -40°C, -50°C, -60°C, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific values ​​included in the range.

[0013] The polyethylene oligomer in this invention is 15-50 parts by weight, for example, 15 parts, 30 parts, 50 parts, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0014] The polypropylene oligomer in this invention is 8-35 parts by weight of polypropylene oligomer, for example, 8 parts, 20 parts, 35 parts, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0015] The hydroxy fluorosilicone oil described in this invention is 3-15 parts by weight, for example, 3 parts, 7 parts, 8 parts, 15 parts, and specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0016] The polyvinylidene fluoride mentioned in this invention is 15-70 parts by weight, for example, 15 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 70 parts, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0017] The initiator described in this invention is 0.05-0.20 parts by weight, for example, 0.05 parts, 0.10 parts, 0.15 parts, 0.20 parts, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0018] The terminating agent described in this invention is 0.5-2.0 parts by weight, for example, 0.5 parts, 1.0 parts, 1.5 parts, 2.0 parts, and specific values ​​between the above-mentioned values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0019] The polyethylene oligomers described in this invention are low molecular weight homopolymers of ethylene polymerized by solution polymerization, including any one or a combination of at least two of linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), and polyethylene wax.

[0020] The polypropylene oligomer described in this invention is obtained by thermal cracking of high molecular weight polypropylene and is a crystalline waxy or soft waxy solid. Brand: WAX wax;

[0021] The hydroxy fluorosilicone oil described in this invention is polytrifluoropropylmethylsiloxane, which can undergo silanization with ethylene oligomers, propylene oligomers and polyvinylidene fluoride under the action of an initiator to prepare ethylene-propylene-vinylidene fluoride polymers.

[0022] The polyvinylidene fluoride described in this invention is a polymer containing vinylidene fluoride, grade: FR916;

[0023] The initiator described in this invention includes any one or a combination of at least two of benzoyl peroxide (BPO), dicumyl peroxide (DCP), tert-butyl peroxide, and tert-butyl peroxide-2-ethylhexanoate (TBPO);

[0024] The terminating agent described in this invention includes any one or a combination of at least two of hydroquinone, p-tert-butylcatechol, and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate];

[0025] In a second aspect, the present invention provides a method for preparing an ethylene-propylene-vinylidene fluoride polymer and a sealing component thereof as described in the first aspect, the method comprising:

[0026] An initiator is used to promote the silanization of ethylene oligomers, propylene oligomers, polyvinylidene fluoride, and ethylene. After complete silanization, the reaction is terminated by a terminator to prepare an ethylene-propylene-vinylidene fluoride polymer. Finally, low-temperature and oil-resistant special seals are prepared by mixing and vulcanization molding.

[0027] Preferably, the preparation method specifically includes:

[0028] (1) In a reactive screw extruder, polyethylene oligomer, polypropylene oligomer, hydroxyl fluorosilicone oil and polyvinylidene fluoride are mixed to obtain a first mixture;

[0029] (2) In a reactive screw extruder, an initiator is added to the first mixture to carry out silanization to obtain a second mixture;

[0030] (3) In a closed rubber mixing mill, the second mixture and silica are fully silanized to obtain the third mixture;

[0031] (4) In a closed rubber mixing mill, a terminator is added to the third mixture to terminate the reaction and obtain an ethylene-propylene-vinylidene fluoride polymer.

[0032] (5) In a closed rubber mixing mill, stearic acid, zinc oxide, vulcanization accelerator, vulcanizing agent, antioxidant, and plasticizer are added to the ethylene-propylene-vinylidene fluoride polymer for mixing to obtain a fourth mixture. The fourth mixture is vulcanized and molded in a flat vulcanizing mill to obtain an ethylene-propylene-vinylidene fluoride polymer seal.

[0033] Step (1) is mainly to mix polyethylene oligomer, polypropylene oligomer, hydroxyl fluorosilicone oil and polyvinylidene fluoride evenly, making it easier to carry out the reverse silanization reaction; Step (2) the initiator in the reaction screw extruder carries out the silanization effect; Step (3) is to fully silanize the second mixture and silica, and mix the polymer and silica evenly; Step (4) is to terminate the silanization of the mixture and prepare ethylene-propylene-vinylidene fluoride polymer; Step (5) is to mix and vulcanize the ethylene-propylene-vinylidene fluoride polymer and finally prepare a low-temperature resistant and oil-resistant special sealing part;

[0034] In step (1) of this invention, the reaction screw extruder mixing temperature is 145-200℃, for example, it can be 145℃, 150℃, 160℃, 170℃, 200℃, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0035] In step (1) of this invention, the reaction screw extruder mixing speed is 15-60 rpm, for example, it can be 15 rpm, 30 rpm, 40 rpm, 60 rpm, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0036] In this invention, the reaction screw extruder mixing in step (1) has a reaction time of 1 to 8 minutes, for example, 1 minute, 2 minutes, 3 minutes, 8 minutes, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0037] In step (2) of this invention, the silanization reaction of the screw extruder is carried out at a temperature of 95 to 170°C. For example, it can be 95°C, 110°C, 120°C, 130°C, 140°C, 150°C, 170°C, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0038] In step (2) of this invention, the screw extruder silanization reaction is performed at a speed of 8-60 rpm, for example, 8 rpm, 20 rpm, 30 rpm, 40 rpm, 60 rpm, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0039] In step (2) of this invention, the silanization reaction of the screw extruder has a reaction time of 1 to 6 minutes, for example, 1 minute, 3 minutes, 4 minutes, 6 minutes, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0040] In this invention, the screw extruder extrusion in steps (1) and (2) is used with an extrusion pressure of 12 to 22 MPa, for example, 12 MPa, 15 MPa, 20 MPa, 22 MPa, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0041] In step (3) of this invention, the silanization reaction is fully carried out in the closed rubber mixing mill at a temperature of 135-170°C. For example, it can be 135°C, 150°C, 170°C, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0042] In step (3) of this invention, the closed rubber mixing mill is used for full silanization reaction at a speed of 35-65 rpm, for example, 35 rpm, 50 rpm, 65 rpm, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0043] In step (3) of this invention, the silanization reaction in the closed rubber mixing mill takes 2 to 6 minutes, for example, 2 minutes, 4 minutes, 6 minutes, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0044] In this invention, step (4) is terminated in a closed rubber mixing mill at a temperature of 110-160°C, for example, 110°C, 130°C, 140°C, 160°C, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0045] In this invention, step (4) is terminated in the closed rubber mixing mill, with a rotation speed of 15-65 rpm. For example, it can be 15 rpm, 30 rpm, 40 rpm, 50 rpm, 65 rpm, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0046] In this invention, the closed rubber mixing mill described in step (4) is terminated for a time of 2 to 8 minutes, for example, 2 minutes, 4 minutes, 5 minutes, 8 minutes, and specific point values ​​between the above points. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific point values ​​included in the range.

[0047] In step (5) of this invention, the temperature of the closed rubber mixing machine is 110-150℃, for example, it can be 110℃, 130℃, 150℃, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0048] In step (5) of this invention, the closed rubber mixing machine is used for mixing at a speed of 15-60 rpm, for example, it can be 15 rpm, 30 rpm, 40 rpm, 60 rpm, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0049] In step (5) of this invention, the mixing time of the closed rubber mixing machine is 2 to 8 minutes, for example, 2 minutes, 4 minutes, 8 minutes, and specific point values ​​between the above points. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific point values ​​included in the range.

[0050] In step (5) of this invention, the vulcanization molding temperature of the flat vulcanizing machine is 140-190℃, for example, it can be 140℃, 160℃, 170℃, 190℃, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0051] In step (5) of this invention, the pressure of the flat vulcanizing machine is 3-15 MPa, for example, it can be 3 MPa, 7 MPa, 8 MPa, 9 MPa, 10 MPa, 15 MPa, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0052] In this invention, the vulcanization molding in step (5) takes 15 to 50 minutes, for example, 25 minutes, 30 minutes, 35 minutes, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0053] In this invention, polyethylene oligomers, polypropylene oligomers, hydroxyl fluorosilicone oil, and polyvinylidene fluoride (PVDF) are first mixed in a specific mass ratio using a reactive screw extruder. An initiator is then added to initiate a silanization reaction. Next, the mixture is further silanized with silica. Finally, a terminator is added to terminate the reaction, yielding an ethylene-propylene-vinylidene fluoride polymer. The polymer is then compounded, vulcanized, and molded to obtain an ethylene-propylene-vinylidene fluoride polymer seal. Compared to existing technologies, the product of this invention significantly improves low-temperature resistance, oil resistance, and aging resistance, and effectively reduces the compression set of the seal.

[0054] The reactive screw extruder used in this invention is a general-purpose polymer processing equipment with a temperature control range of 30 to 350°C and a speed control range of 10 to 120 rpm. There is no specific model limit, as long as the equipment meets the requirements for safe use and can mix low molecular weight polyethylene, low molecular weight polypropylene, hydroxyl fluorosilicone oil, polyvinylidene fluoride, initiator and terminator evenly.

[0055] The closed rubber mixing mill used in this invention is a general-purpose polymer processing equipment with a temperature control range of 30 to 200°C and a speed control range of 20 to 100 rpm. There is no specific model limit, as long as the equipment meets the requirements of safe use and can mix the materials, additives and fillers evenly.

[0056] The flat vulcanizing machine used in this invention is a general-purpose polymer processing equipment with a temperature control range of 30 to 350°C and a pressure control range of 2 to 15 MPa. There is no specific model limit, as long as the equipment meets the requirements for safe use and can vulcanize the compound into shape.

[0057] Thirdly, the present invention provides a method for preparing an ethylene-propylene-vinylidene fluoride polymer and a sealing component thereof as described in the first aspect.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] This invention provides a method for preparing an ethylene-propylene-vinylidene fluoride polymer and its sealing components. Under the action of an initiator, ethylene oligomers, propylene oligomers, hydroxyl fluorosilicone oil, polyvinylidene fluoride, and silica undergo a silanization reaction, which is further terminated to obtain the ethylene-propylene-vinylidene fluoride polymer. Finally, the polymer is mixed with additives and vulcanized to obtain a special low-temperature and oil-resistant sealing component. This invention solves the problems of poor low-temperature resistance, oil resistance, aging resistance, and compression set in existing technologies for preparing vinylidene fluoride polymers. The product achieves a compression resistance coefficient of over 0.3 at -50℃, with a compression set of less than 20%, and significantly improved oil resistance and aging resistance compared to existing products. Detailed Implementation

[0060] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0061] The experimental materials used in the embodiments and comparative examples of this invention are as follows:

[0062] 20-40 parts polyethylene oligomer, 10-30 parts polypropylene oligomer, 5-10 parts hydroxyl fluorosilicone oil, 20-65 parts polyvinylidene fluoride, 0.05-0.20 parts initiator and 0.5-2.0 parts terminator, 30 parts silica A380, 1 part stearic acid, 5 parts zinc oxide, 3 parts TAIC vulcanization accelerator, 1.5 parts vulcanizing agent bis-25, 1 part antioxidant 4010NA and 5 parts perfluoroether oil.

[0063] (1) Polyethylene oligomers are low molecular weight homopolymers of ethylene produced by solution polymerization. Among them, linear low-density polyethylene (LLDPE) is a product of Sinopec Qilu Petrochemical Company, grade: F182MT; low-density polyethylene (LDPE) is a product of Sinopec Maoming Petrochemical Company, grade: 2426H; and polyethylene wax is a product of Wuhan Xindongyi Chemical Co., Ltd., grade: 400PE.

[0064] (2) Polypropylene oligomers are obtained by thermal cracking of high molecular weight polypropylene and are crystalline waxy or soft waxy solids. A product of Dongguan Xingyuan Chemical Co., Ltd., brand name WAX ​​wax;

[0065] (3) Hydroxyfluorosilicone oil is polytrifluoropropylmethylsiloxane, which can undergo silanization with ethylene oligomers, propylene oligomers and polyvinylidene fluoride under the action of an initiator, and prepare ethylene-propylene-vinylidene fluoride polymers in a reactive screw extruder. CAS: 63148-56-1, product of Wuhan Smike Biotechnology Co., Ltd.;

[0066] (4) Polyvinylidene fluoride is a polymer containing vinylidene fluoride, brand name: FR916, a product of Shanghai Huayi Sanaifu New Materials Co., Ltd.

[0067] (5) Initiators include benzoyl peroxide (BPO), dicumyl peroxide (DCP), tert-butyl peroxide and tert-butyl peroxide-2-ethylhexanoate (TBPO), products of Dalian Ruisheng Rubber & Plastic Materials Co., Ltd.

[0068] (6) The terminator is a phenolic terminator, including hydroquinone, p-tert-butylcatechol and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], a product of Dalian Ruisheng Rubber & Plastic Materials Co., Ltd.

[0069] 30 parts silica A380, 1 part stearic acid, 5 parts zinc oxide, 3 parts TAIC vulcanization accelerator, 1.5 parts bis-25 vulcanizing agent, 1 part antioxidant 4010NA and 5 parts perfluoroether oil.

[0070] (7) Stearic acid is a product of Xilong Scientific Co., Ltd., grade: analytical grade (AR);

[0071] (8) Zinc oxide is a product of Tianjin Yongda Chemical Reagent Co., Ltd., grade: analytical grade (AR);

[0072] (9) The vulcanization accelerator is triallyl isocyanurate (accelerator TAIC), a product of Dalian Ruisheng Rubber & Plastic Materials Co., Ltd.

[0073] (10) The vulcanizing agent is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, abbreviated as bis-25, a product of Dalian Ruisheng Rubber & Plastic Materials Co., Ltd.

[0074] (10) The antioxidant is N-isopropyl-N'-phenyl-p-phenylenediamine (antioxidant 4010NA), a product of Dalian Ruisheng Rubber & Plastic Materials Co., Ltd.

[0075] (11) Perfluoropolyether oil is a low molecular weight polymer of perfluoroolefin ether, abbreviated as PEPE. It has good compatibility with polyvinylidene fluoride. Brand: B-2600. Product of Fuzhou Taipuda New Material Co., Ltd.

[0076] Example 1

[0077] This embodiment provides an application in the preparation method of an ethylene-propylene-vinylidene fluoride polymer and its sealing components. The components, by weight, include: 20 parts LLDPE (molecular weight distribution: 1.8), 10 parts polypropylene oligomer WAX wax (molecular weight distribution: 2.9), 5 parts hydroxyl fluorosilicone oil, 65 parts polyvinylidene fluoride (molecular weight distribution: 1.9), 0.05 parts BPO, 0.5 parts hydroquinone, 30 parts silica A380, 1 part stearic acid, 5 parts zinc oxide, 3 parts TAIC vulcanization accelerator, 1.5 parts vulcanizing agent bis-25, 1 part antioxidant 4010NA, and 5 parts perfluoroether oil.

[0078] This embodiment also provides a preparation step for an ethylene-propylene-vinylidene fluoride polymer seal, the preparation step including:

[0079] (1) In a reaction screw extruder, polyethylene oligomer, polypropylene oligomer, hydroxyl fluorosilicone oil and polyvinylidene fluoride are mixed. The mixing temperature of the screw extruder is 150°C, the speed is 20 rpm, and the time is 5 minutes to obtain the first mixture.

[0080] (2) In a reaction screw extruder, an initiator is added to the first mixture to carry out silanization. The mixing temperature of the reaction screw extruder is 100°C, the speed is 10 rpm, and the time is 5 minutes to obtain the second mixture. The mixture is then extruded at an extrusion pressure of 11 MPa.

[0081] (3) In a closed rubber mixing mill, the second mixture and silica are fully silanized. The mixing temperature of the closed rubber mixing mill is 140℃, the speed is 40 rpm, and the time is 5 minutes to obtain the third mixture.

[0082] (4) In a closed rubber mixing mill, the terminator is added to the third mixture to terminate the reaction. The mixing temperature of the closed rubber mixing mill is 120℃, the speed is 20 rpm, and the time is 6 minutes to obtain ethylene-propylene-vinylidene fluoride polymer.

[0083] (5) In a closed rubber mixing mill, stearic acid, zinc oxide, vulcanization accelerator, vulcanizing agent, antioxidant, and plasticizer are added to the ethylene-propylene-vinylidene fluoride polymer for mixing. The mixing temperature of the closed rubber mixing mill is 120℃, the rotation speed is 20 rpm, and the mixing time is 5 minutes to obtain the fourth mixture. The fourth mixture is vulcanized in a flat vulcanizing mill. The temperature of the flat vulcanizing mill is 150℃, the pressure is 5MPa, and the vulcanization time is 40 minutes to obtain ethylene-propylene-vinylidene fluoride polymer seals (compression cold resistance coefficient, compression set, and volume change rate; seal size: diameter 10mm±0.2mm, height 10mm±0.2mm; aging coefficient; seal size: 150mm±0.5mm×150mm±0.5mm). The ethylene-propylene-vinylidene fluoride polymer samples were tested for compression cold resistance coefficient at -40℃ and -50℃, volume change rate of IRM903 oil, aging coefficient and compression set. The test results are shown in Table 1.

[0084] Example 2

[0085] This embodiment provides a method for preparing an ethylene-propylene-vinylidene fluoride polymer and its sealing components. The components, by weight, include: 40 parts LDPE (molecular weight distribution: 5.1), 30 parts polypropylene oligomer WAX wax (molecular weight distribution: 6.2), 10 parts hydroxyl fluorosilicone oil, 20 parts polyvinylidene fluoride (molecular weight distribution: 5.2), 0.20 parts DCP, 2.0 parts p-tert-butylcatechol, 30 parts silica A380, 1 part stearic acid, 5 parts zinc oxide, 3 parts vulcanization accelerator TAIC, 1.5 parts vulcanizing agent bis-25, 1 part antioxidant 4010NA, and 5 parts perfluoroether oil.

[0086] This embodiment also provides a preparation step for an ethylene-propylene-vinylidene fluoride polymer and its sealing components, the preparation step including:

[0087] (1) In a reaction screw extruder, polyethylene oligomer, polypropylene oligomer, hydroxyl fluorosilicone oil and polyvinylidene fluoride are mixed. The mixing temperature of the screw extruder is 190°C, the speed is 60 rpm, and the time is 2 minutes to obtain the first mixture.

[0088] (2) In a reaction screw extruder, an initiator is added to the first mixture to carry out silanization. The mixing temperature of the reaction screw extruder is 160°C, the speed is 50 rpm, and the time is 2 minutes to obtain the second mixture. The mixture is then extruded at an extrusion pressure of 19 MPa.

[0089] (3) In a closed rubber mixing mill, the second mixture and silica are fully silanized. The mixing temperature of the closed rubber mixing mill is 160℃, the speed is 60 rpm, and the time is 3 minutes to obtain the third mixture.

[0090] (4) In a closed rubber mixing mill, the terminator is added to the third mixture to terminate the reaction. The mixing temperature of the closed rubber mixing mill is 150℃, the speed is 60 rpm, and the time is 3 minutes to obtain ethylene-propylene-vinylidene fluoride polymer.

[0091] (5) In a closed rubber mixing mill, stearic acid, zinc oxide, vulcanization accelerator, vulcanizing agent, antioxidant, and plasticizer are added to the ethylene-propylene-vinylidene fluoride polymer for mixing. The mixing temperature of the closed rubber mixing mill is 140℃, the rotation speed is 50 rpm, and the mixing time is 3 minutes to obtain the fourth mixture. The fourth mixture is vulcanized in a flat vulcanizing mill. The temperature of the flat vulcanizing mill is 180℃, the pressure is 12MPa, and the vulcanization time is 20 minutes to obtain ethylene-propylene-vinylidene fluoride polymer seals (compression cold resistance coefficient, compression set, and volume change rate; seal size: diameter 10mm±0.2mm, height 10mm±0.2mm; aging coefficient; seal size: 150mm±0.5mm×150mm±0.5mm). The ethylene-propylene-vinylidene fluoride polymer samples were tested for compression cold resistance coefficient at -40℃ and -50℃, volume change rate of IRM903 oil, aging coefficient and compression set. The test results are shown in Table 1.

[0092] Example 3

[0093] This embodiment provides a method for preparing an ethylene-propylene-vinylidene fluoride polymer and its sealing components. The components, by weight, include: 30 parts polyethylene wax (molecular weight distribution: 1.9), 20 parts polypropylene oligomer WAX wax (molecular weight distribution: 6.1), 8 parts hydroxyl fluorosilicone oil, 42 parts polyvinylidene fluoride (molecular weight distribution: 1.9), 0.10 parts benzoyl tert-butyl peroxide, 1.0 part pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 30 parts silica A380, 1 part stearic acid, 5 parts zinc oxide, 3 parts vulcanization accelerator TAIC, 1.5 parts vulcanizing agent bis-25, 1 part antioxidant 4010NA, and 5 parts perfluoroether oil.

[0094] This embodiment also provides a preparation step for an ethylene-propylene-vinylidene fluoride polymer and its sealing components, the preparation step including:

[0095] (1) In a reaction screw extruder, polyethylene oligomer, polypropylene oligomer, hydroxyl fluorosilicone oil and polyvinylidene fluoride are mixed. The mixing temperature of the screw extruder is 160°C, the speed is 40 rpm, and the time is 3 minutes to obtain the first mixture.

[0096] (2) In a reaction screw extruder, an initiator is added to the first mixture to carry out silanization. The mixing temperature of the reaction screw extruder is 120°C, the speed is 30 rpm, and the time is 3 minutes to obtain the second mixture. The mixture is then extruded at an extrusion pressure of 11 MPa.

[0097] (3) In a closed rubber mixing mill, the second mixture and silica are fully silanized. The mixing temperature of the closed rubber mixing mill is 150℃, the speed is 50 rpm, and the time is 4 minutes to obtain the third mixture.

[0098] (4) In a closed rubber mixing mill, the terminator is added to the third mixture to terminate the reaction. The mixing temperature of the closed rubber mixing mill is 130℃, the speed is 40 rpm, and the time is 5 minutes to obtain ethylene-propylene-vinylidene fluoride polymer.

[0099] (5) In a closed rubber mixing mill, stearic acid, zinc oxide, vulcanization accelerator, vulcanizing agent, antioxidant, and plasticizer are added to the ethylene-propylene-vinylidene fluoride polymer for mixing. The mixing temperature of the closed rubber mixing mill is 130℃, the rotation speed is 40 rpm, and the mixing time is 4 minutes to obtain the fourth mixture. The fourth mixture is vulcanized in a flat vulcanizing mill. The temperature of the flat vulcanizing mill is 160℃, the pressure is 10MPa, and the vulcanization time is 30 minutes to obtain ethylene-propylene-vinylidene fluoride polymer seals (compression cold resistance coefficient, compression set, and volume change rate; seal size: diameter 10mm±0.2mm, height 10mm±0.2mm; aging coefficient; seal size: 150mm±0.5mm×150mm±0.5mm). The ethylene-propylene-vinylidene fluoride polymer samples were tested for compression cold resistance coefficient at -40℃ and -50℃, volume change rate of IRM903 oil, aging coefficient and compression set. The test results are shown in Table 1.

[0100] Example 4

[0101] This embodiment provides a method for preparing an ethylene-propylene-vinylidene fluoride polymer and its sealing components. The components, by weight, include: 30 parts LLDPE (molecular weight distribution 5.1), 20 parts polypropylene oligomer WAX wax (molecular weight distribution 6.2), 6 parts hydroxyl fluorosilicone oil, 44 parts polyvinylidene fluoride (molecular weight distribution 1.9), 0.05 parts TBPO, 1 part hydroquinone, 30 parts silica A380, 1 part stearic acid, 5 parts zinc oxide, 3 parts TAIC vulcanization accelerator, 1.5 parts bis-25 vulcanizing agent, 1 part antioxidant 4010NA, and 5 parts perfluoroether oil.

[0102] This embodiment also provides a preparation step for an ethylene-propylene-vinylidene fluoride polymer and its sealing components, the preparation step including:

[0103] (1) In a reaction screw extruder, polyethylene oligomer, polypropylene oligomer, hydroxyl fluorosilicone oil and polyvinylidene fluoride are mixed. The mixing temperature of the screw extruder is 140°C, the speed is 40 rpm, and the time is 3 minutes to obtain the first mixture.

[0104] (2) In a reaction screw extruder, an initiator is added to the first mixture to carry out silanization. The mixing temperature of the reaction screw extruder is 140°C, the speed is 40 rpm, and the time is 3 minutes to obtain the second mixture. The mixture is then extruded at an extrusion pressure of 19 MPa.

[0105] (3) In a closed rubber mixing mill, the second mixture and silica are fully silanized. The mixing temperature of the closed rubber mixing mill is 140℃, the speed is 40 rpm, and the time is 3 minutes to obtain the third mixture.

[0106] (4) In a closed rubber mixing mill, the terminator is added to the third mixture to terminate the reaction. The mixing temperature of the closed rubber mixing mill is 140℃, the speed is 40 rpm, and the time is 3 minutes to obtain ethylene-propylene-vinylidene fluoride polymer.

[0107] (5) In a closed rubber mixing mill, stearic acid, zinc oxide, vulcanization accelerator, vulcanizing agent, antioxidant, and plasticizer are added to the ethylene-propylene-vinylidene fluoride polymer for mixing. The mixing temperature of the closed rubber mixing mill is 140℃, the rotation speed is 40 rpm, and the mixing time is 3 minutes to obtain the fourth mixture. The fourth mixture is vulcanized in a flat vulcanizing mill. The temperature of the flat vulcanizing mill is 150℃, the pressure is 8MPa, and the vulcanization time is 25 minutes to obtain ethylene-propylene-vinylidene fluoride polymer seals (compression cold resistance coefficient, compression set, and volume change rate; seal size: diameter 10mm±0.2mm, height 10mm±0.2mm; aging coefficient; seal size: 150mm±0.5mm×150mm±0.5mm). The ethylene-propylene-vinylidene fluoride polymer samples were tested for compression cold resistance coefficient at -40℃ and -50℃, volume change rate of IRM903 oil, aging coefficient and compression set. The test results are shown in Table 1.

[0108] Example 5

[0109] This embodiment provides a method for preparing an ethylene-propylene-vinylidene fluoride polymer and its sealing components. The components, by weight, include: 40 parts polyethylene wax (molecular weight distribution 1.9), 30 parts polypropylene oligomer WAX wax (molecular weight distribution 2.8), 5 parts hydroxyl fluorosilicone oil, 25 parts polyvinylidene fluoride (molecular weight distribution 5.1), 0.10 parts benzoyl tert-butyl peroxide, 0.5 parts hydroquinone, 0.5 parts p-tert-butylcatechol, 30 parts silica A380, 1 part stearic acid, 5 parts zinc oxide, 3 parts vulcanization accelerator TAIC, 1.5 parts vulcanizing agent bis-25, 1 part antioxidant 4010NA, and 5 parts perfluoroether oil.

[0110] This embodiment also provides a preparation step for an ethylene-propylene-vinylidene fluoride polymer and its sealing components, the preparation step including:

[0111] (1) In a reaction screw extruder, polyethylene oligomer, polypropylene oligomer, hydroxyl fluorosilicone oil and polyvinylidene fluoride are mixed. The mixing temperature of the screw extruder is 180°C, the speed is 50 rpm, and the time is 2 minutes to obtain the first mixture.

[0112] (2) In a reaction screw extruder, an initiator is added to the first mixture to carry out silanization. The mixing temperature of the reaction screw extruder is 150°C, the speed is 50 rpm, and the time is 2 minutes to obtain the second mixture. The mixture is then extruded at an extrusion pressure of 11 MPa.

[0113] (3) In a closed rubber mixing mill, the second mixture and silica are fully silanized. The mixing temperature of the closed rubber mixing mill is 150℃, the speed is 50 rpm, and the time is 4 minutes to obtain the third mixture.

[0114] (4) In a closed rubber mixing mill, the terminator is added to the third mixture to terminate the reaction. The mixing temperature of the closed rubber mixing mill is 140℃, the speed is 50 rpm, and the time is 4 minutes to obtain ethylene-propylene-vinylidene fluoride polymer.

[0115] (5) In a closed rubber mixing mill, stearic acid, zinc oxide, vulcanization accelerator, vulcanizing agent, antioxidant, and plasticizer are added to the ethylene-propylene-vinylidene fluoride polymer for mixing. The mixing temperature of the closed rubber mixing mill is 130℃, the rotation speed is 50 rpm, and the mixing time is 3 minutes to obtain the fourth mixture. The fourth mixture is vulcanized in a flat vulcanizing mill. The temperature of the flat vulcanizing mill is 170℃, the pressure is 8MPa, and the vulcanization time is 35 minutes to obtain ethylene-propylene-vinylidene fluoride polymer seals (compression cold resistance coefficient, compression set, and volume change rate; seal size: diameter 10mm±0.2mm, height 10mm±0.2mm; aging coefficient; seal size: 150mm±0.5mm×150mm±0.5mm). The ethylene-propylene-vinylidene fluoride polymer samples were tested for compression cold resistance coefficient at -40℃ and -50℃, volume change rate of IRM903 oil, aging coefficient and compression set. The test results are shown in Table 1.

[0116] Example 6

[0117] This embodiment provides a method for preparing an ethylene-propylene-vinylidene fluoride polymer and its sealing components. The components, by weight, include: 20 parts LLDPE (molecular weight distribution 1.8), 10 parts LDPE (molecular weight distribution 1.9), 20 parts polypropylene oligomer WAX wax (molecular weight distribution 6.2), 10 parts hydroxyl fluorosilicone oil, 40 parts polyvinylidene fluoride (molecular weight distribution 1.9), 0.05 parts BPO, 0.05 parts TBPO, 0.5 parts hydroquinone, 0.5 parts pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 30 parts silica A380, 1 part stearic acid, 5 parts zinc oxide, 3 parts TAIC vulcanization accelerator, 1.5 parts bis-25 vulcanizing agent, 1 part antioxidant 4010NA, and 5 parts perfluoroether oil.

[0118] This embodiment also provides a preparation step for an ethylene-propylene-vinylidene fluoride polymer and its sealing components, the preparation step including:

[0119] (1) In a reaction screw extruder, polyethylene oligomer, polypropylene oligomer, hydroxyl fluorosilicone oil and polyvinylidene fluoride are mixed. The mixing temperature of the screw extruder is 170°C, the speed is 20 rpm, and the time is 5 minutes to obtain the first mixture.

[0120] (2) In a reaction screw extruder, an initiator is added to the first mixture to carry out silanization. The mixing temperature of the reaction screw extruder is 140°C, the speed is 20 rpm, and the time is 5 minutes to obtain the second mixture. The mixture is then extruded at an extrusion pressure of 20 MPa.

[0121] (3) In a closed rubber mixing mill, the second mixture and silica are fully silanized. The mixing temperature of the closed rubber mixing mill is 150℃, the speed is 40 rpm, and the time is 5 minutes to obtain the third mixture.

[0122] (4) In a closed rubber mixing mill, the terminator is added to the third mixture to terminate the reaction. The mixing temperature of the closed rubber mixing mill is 130℃, the speed is 30 rpm, and the time is 5 minutes to obtain ethylene-propylene-vinylidene fluoride polymer.

[0123] (5) In a closed rubber mixing mill, stearic acid, zinc oxide, vulcanization accelerator, vulcanizing agent, antioxidant, and plasticizer are added to the ethylene-propylene-vinylidene fluoride polymer for mixing. The mixing temperature of the closed rubber mixing mill is 135℃, the rotation speed is 35 rpm, and the mixing time is 4 minutes to obtain the fourth mixture. The fourth mixture is vulcanized in a flat vulcanizing mill. The temperature of the flat vulcanizing mill is 170℃, the pressure is 10MPa, and the vulcanization time is 20 minutes to obtain ethylene-propylene-vinylidene fluoride polymer seals (compression cold resistance coefficient, compression set, and volume change rate; seal size: diameter 10mm±0.2mm, height 10mm±0.2mm; aging coefficient; seal size: 150mm±0.5mm×150mm±0.5mm). The ethylene-propylene-vinylidene fluoride polymer samples were tested for compression cold resistance coefficient at -40℃ and -50℃, volume change rate of IRM903 oil, aging coefficient and compression set. The test results are shown in Table 1.

[0124] Example 7

[0125] This embodiment provides a method for preparing an ethylene-propylene-vinylidene fluoride polymer and its sealing components. The components, by weight, include: 10 parts LLDPE (molecular weight distribution 1.9), 10 parts LDPE (molecular weight distribution 1.8), 10 parts polyethylene wax (molecular weight distribution 5.1), 10 parts polypropylene oligomer WAX wax (molecular weight distribution 6.2), 10 parts hydroxyl fluorosilicone oil, 50 parts polyvinylidene fluoride (molecular weight distribution 1.9), and 0.0 5 parts BPO, 0.05 parts benzoyl tert-butyl peroxide, 0.05 parts TBPO, 0.5 parts hydroquinone, 0.5 parts p-tert-butylcatechol, 0.5 parts pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 30 parts silica A380, 1 part stearic acid, 5 parts zinc oxide, 3 parts TAIC vulcanization accelerator, 1.5 parts bis-25 vulcanizing agent, 1 part antioxidant 4010NA and 5 parts perfluoroether oil.

[0126] This embodiment also provides a preparation step for an ethylene-propylene-vinylidene fluoride polymer and its sealing components, the preparation step including:

[0127] (1) In a reaction screw extruder, polyethylene oligomer, polypropylene oligomer, hydroxyl fluorosilicone oil and polyvinylidene fluoride are mixed. The mixing temperature of the screw extruder is 180°C, the speed is 40 rpm, and the time is 4 minutes to obtain the first mixture.

[0128] (2) In a reaction screw extruder, an initiator is added to the first mixture to carry out silanization. The mixing temperature of the reaction screw extruder is 130°C, the speed is 30 rpm, and the time is 3 minutes to obtain the second mixture. The mixture is then extruded at an extrusion pressure of 10 MPa.

[0129] (3) In a closed rubber mixing mill, the second mixture and silica are fully silanized. The mixing temperature of the closed rubber mixing mill is 150℃, the speed is 40 rpm, and the time is 5 minutes to obtain the third mixture.

[0130] (4) In a closed rubber mixing mill, the terminator is added to the third mixture to terminate the reaction. The mixing temperature of the closed rubber mixing mill is 130℃, the speed is 40 rpm, and the time is 5 minutes to obtain ethylene-propylene-vinylidene fluoride polymer.

[0131] (5) In a closed rubber mixing mill, stearic acid, zinc oxide, vulcanization accelerator, vulcanizing agent, antioxidant, and plasticizer were added to the ethylene-propylene-vinylidene fluoride polymer for mixing. The mixing temperature of the closed rubber mixing mill was 130℃, the rotation speed was 30 rpm, and the mixing time was 4 minutes to obtain the fourth mixture. The fourth mixture was vulcanized in a flat vulcanizing mill. The temperature of the flat vulcanizing mill was 160℃, the pressure was 10MPa, and the vulcanization time was 35 minutes to obtain ethylene-propylene-vinylidene fluoride polymer seals (compression cold resistance coefficient, compression set, and volume change rate; seal size: diameter 10mm±0.2mm, height 10mm±0.2mm; aging coefficient; seal size: 150mm±0.5mm×150mm±0.5mm). The seals were tested for compression cold resistance coefficient at -40℃ and -50℃, volume change rate of IRM903 oil, aging coefficient, and compression set. The test results are shown in Table 1.

[0132] Comparative Example 1

[0133] This comparative example provides a method for preparing an ethylene-propylene-vinylidene fluoride polymer and its sealing components. The components, by weight, include: 30 parts LLDPE (molecular weight distribution 5.1), 20 parts polypropylene oligomer WAX wax (molecular weight distribution 6.2), 6 parts hydroxyl fluorosilicone oil, 44 parts polyvinylidene fluoride (molecular weight distribution 1.9), 0.05 parts TBPO, 1 part hydroquinone, 30 parts silica A380, 1 part stearic acid, 5 parts zinc oxide, 3 parts TAIC vulcanization accelerator, 1.5 parts vulcanizing agent bis-25, 1 part antioxidant 4010NA, and 5 parts perfluoroether oil.

[0134] This comparative example also provides a preparation step for an ethylene-propylene-vinylidene fluoride polymer and its sealing component, the preparation step including:

[0135] (1) In a reaction screw extruder, polyethylene oligomer, polypropylene oligomer, hydroxyl fluorosilicone oil, polyvinylidene fluoride and initiator are mixed. The mixing temperature of the screw extruder is 140℃, the speed is 40 rpm, and the time is 6 minutes to obtain the first mixture. The mixture is then extruded at an extrusion pressure of 19 MPa.

[0136] (2) In a closed rubber mixing mill, the first mixture and silica are fully silanized. The mixing temperature of the closed rubber mixing mill is 140℃, the speed is 40 rpm, and the time is 3 minutes to obtain the second mixture.

[0137] (3) In a closed rubber mixing mill, the terminator is added to the second mixture to terminate the reaction. The mixing temperature of the closed rubber mixing mill is 140℃, the speed is 40 rpm, and the time is 3 minutes to obtain ethylene-propylene-vinylidene fluoride polymer.

[0138] (4) In a closed rubber mixing mill, ethylene-propylene-vinylidene fluoride polymer, stearic acid, zinc oxide, vulcanization accelerator, vulcanizing agent, antioxidant, and plasticizer were added and mixed. The mixing temperature of the closed rubber mixing mill was 140℃, the rotation speed was 40 rpm, and the mixing time was 3 minutes to obtain the third mixture. The third mixture was vulcanized in a flat vulcanizing mill. The temperature of the flat vulcanizing mill was 150℃, the pressure was 8MPa, and the vulcanization time was 25 minutes to obtain ethylene-propylene-vinylidene fluoride polymer seals (compression cold resistance coefficient, compression set, and volume change rate; seal size: diameter 10mm±0.2mm, height 10mm±0.2mm; aging coefficient; seal size: 150mm±0.5mm×150mm±0.5mm). The product / sample was tested for compression cold resistance coefficient at -40℃ and -50℃, volume change rate of IRM903 oil, aging coefficient, and compression set. The test results are shown in Table 1.

[0139] Comparative Example 2

[0140] This comparative example provides a method for preparing an ethylene-propylene-vinylidene fluoride polymer and its sealing components. The components, by weight, include: 30 parts LLDPE (molecular weight distribution 5.1), 20 parts polypropylene oligomer WAX wax (molecular weight distribution 6.2), 6 parts hydroxyl fluorosilicone oil, 44 parts polyvinylidene fluoride (molecular weight distribution 1.9), 0.05 parts TBPO, 1 part hydroquinone, 30 parts silica A380, 1 part stearic acid, 5 parts zinc oxide, 3 parts TAIC vulcanization accelerator, 1.5 parts vulcanizing agent bis-25, 1 part antioxidant 4010NA, and 5 parts perfluoroether oil.

[0141] This comparative example also provides a preparation step for an ethylene-propylene-vinylidene fluoride polymer and its sealing component, the preparation step including:

[0142] (1) In a reaction screw extruder, polyethylene oligomer, polypropylene oligomer, hydroxyl fluorosilicone oil, polyvinylidene fluoride and initiator are mixed. The mixing temperature of the screw extruder is 140℃, the speed is 40 rpm, and the time is 6 minutes to obtain the first mixture. The mixture is then extruded at an extrusion pressure of 19 MPa.

[0143] (2) In a closed rubber mixing mill, the first mixture, silica and terminator are mixed. The mixing temperature of the closed rubber mixing mill is 140℃, the speed is 40 rpm, and the time is 6 minutes to obtain ethylene-propylene-vinylidene fluoride polymer.

[0144] (3) In a closed rubber mixing mill, ethylene-propylene-vinylidene fluoride polymer, stearic acid, zinc oxide, vulcanization accelerator, vulcanizing agent, antioxidant, and plasticizer were added and mixed. The mixing temperature of the closed rubber mixing mill was 140℃, the rotation speed was 40 rpm, and the mixing time was 3 minutes to obtain the third mixture. The third mixture was vulcanized in a flat vulcanizing mill. The temperature of the flat vulcanizing mill was 150℃, the pressure was 8MPa, and the vulcanization time was 25 minutes to obtain ethylene-propylene-vinylidene fluoride polymer seals (compression cold resistance coefficient, compression set, and volume change rate; seal size: diameter 10mm±0.2mm, height 10mm±0.2mm; aging coefficient; seal size: 150mm±0.5mm×150mm±0.5mm). The product / sample was tested for compression cold resistance coefficient at -40℃ and -50℃, volume change rate of IRM903 oil, aging coefficient, and compression set. The test results are shown in Table 1.

[0145] Comparative Example 3

[0146] This comparative example provides a method for preparing an ethylene-propylene-vinylidene fluoride polymer and its sealing components. The components, by weight, include: 30 parts LLDPE (molecular weight distribution 5.1), 20 parts polypropylene oligomer WAX wax (molecular weight distribution 6.2), 6 parts hydroxyl fluorosilicone oil, 44 parts polyvinylidene fluoride (molecular weight distribution 1.9), 0.05 parts TBPO, 1 part hydroquinone, 30 parts silica A380, 1 part stearic acid, 5 parts zinc oxide, 3 parts TAIC vulcanization accelerator, 1.5 parts vulcanizing agent bis-25, 1 part antioxidant 4010NA, and 5 parts perfluoroether oil.

[0147] This comparative example also provides a preparation step for an ethylene-propylene-vinylidene fluoride polymer and its sealing component, the preparation step including:

[0148] (1) In a reaction screw extruder, polyethylene oligomer, polypropylene oligomer, hydroxyl fluorosilicone oil, polyvinylidene fluoride and initiator are mixed. The mixing temperature of the screw extruder is 140℃, the speed is 40 rpm, and the time is 6 minutes to obtain the first mixture. The mixture is then extruded at an extrusion pressure of 19 MPa.

[0149] (2) In a closed rubber mixing mill, the first mixture, silica, terminator, stearic acid, zinc oxide, vulcanization accelerator, vulcanizing agent, antioxidant, and plasticizer were added and mixed. The mixing temperature of the closed rubber mixing mill was 140℃, the rotation speed was 40 rpm, and the mixing time was 9 minutes to obtain the third mixture. The third mixture was vulcanized in a flat vulcanizing mill. The temperature of the flat vulcanizing mill was 150℃, the pressure was 8MPa, and the vulcanization time was 25 minutes to obtain ethylene-propylene-vinylidene fluoride polymer seals (compression cold resistance coefficient, compression set, and volume change rate; seal size: diameter 10mm±0.2mm, height 10mm±0.2mm; aging coefficient; seal size: 150mm±0.5mm×150mm±0.5mm). The product / sample was tested for compression cold resistance coefficient at -40℃ and -50℃, volume change rate of IRM903 oil, aging coefficient, and compression set. The test results are shown in Table 1.

[0150] Comparative Example 4

[0151] This comparative example provides a method for preparing an ethylene-propylene-vinylidene fluoride polymer and its sealing components. The components, by weight, include: 30 parts LLDPE (molecular weight distribution 5.1), 20 parts polypropylene oligomer WAX wax (molecular weight distribution 6.2), 6 parts hydroxyl fluorosilicone oil, 44 parts polyvinylidene fluoride (molecular weight distribution 1.9), 0.05 parts TBPO, 1 part hydroquinone, 30 parts silica A380, 1 part stearic acid, 5 parts zinc oxide, 3 parts TAIC vulcanization accelerator, 1.5 parts vulcanizing agent bis-25, 1 part antioxidant 4010NA, and 5 parts perfluoroether oil.

[0152] This comparative example also provides a preparation step for an ethylene-propylene-vinylidene fluoride polymer and its sealing component, the preparation step including:

[0153] In a closed rubber mixing mill, polyethylene oligomer, polypropylene oligomer, hydroxyl fluorosilicone oil, polyvinylidene fluoride, initiator, silica, terminator, stearic acid, zinc oxide, vulcanization accelerator, vulcanizing agent, antioxidant, and plasticizer are added and mixed. The mixing temperature in the closed rubber mixing mill is 140℃, the rotation speed is 40 rpm, and the mixing time is 12 minutes to obtain a third mixture. The third mixture is vulcanized in a flat vulcanizing mill at a temperature of 150℃, a pressure of 8 MPa, and a vulcanization time of 25 minutes to obtain ethylene-propylene-vinylidene fluoride polymer seals (compression cold resistance coefficient, compression set, and volume change rate; seal dimensions: diameter 10mm±0.2mm, height 10mm±0.2mm; aging coefficient; seal dimensions: 150mm±0.5mm×150mm±0.5mm). The product / sample was tested for compression cold resistance coefficient at -40℃ and -50℃, volume change rate of IRM903 oil, aging coefficient and compression set. The test results are shown in Table 1.

[0154] The performance of the ethylene-propylene-vinylidene fluoride polymer seals provided in Examples 1-7 and Comparative Examples 1-3 was tested using the following methods:

[0155] (1) The cold resistance coefficient of compression is tested according to the industry standard "HG / T 3866-2008 Determination of the cold resistance coefficient of vulcanized rubber" at test temperatures of -40℃ and -50℃;

[0156] (2) The oil resistance test shall be conducted in accordance with the “GB / T 1690-2010 Test method for liquid resistance of vulcanized rubber or thermoplastic rubber”, with test conditions of 70℃×96h and oil type: conforming to ASTM standard IRM903 type oil;

[0157] The volume change rate is calculated according to the following formula: Volume change rate = [(Volume of sample after oil resistance test - Volume of sample before oil resistance test) × 100%] ÷ Volume of sample before oil resistance test;

[0158] (3) Aging coefficient: Tested according to "GB / T 3512-201 Accelerated aging and heat resistance test of vulcanized rubber or thermoplastic rubber in hot air", and determined based on the change in the product of tensile strength and elongation at break of the sample. Aging coefficient = [tensile strength after aging (MPa) × elongation at break (%)] ÷ [tensile strength before aging (MPa) × elongation at break before aging (%)], test conditions: 200℃ × 240 hours;

[0159] (4) Compression set was tested according to the national standard "GB / T 1683-2018 Determination of Compression Set of Vulcanized Rubber under Constant Deformation". Test conditions: 150℃ × 72 hours, compression 25%;

[0160] Table 1

[0161]

[0162]

[0163] As can be seen from Examples 1-7, although the compression resistance coefficient, volume change rate, aging coefficient and compression set of the materials vary slightly depending on the preparation method of the ethylene-propylene-vinylidene fluoride polymer, the type and amount of additives, the properties of the materials provided in the examples are all superior to those of the products of the prior art and have the value of promotion and application.

[0164] Analysis of Examples 4, 1, 2, 3, and 4 shows that the performance of the ethylene-propylene-vinylidene fluoride polymer seals provided in these examples is superior to that of Comparative Example 1 (which reduces step (2)), Comparative Example 2 (which reduces steps (1) and (2)), and Comparative Example 3 (which reduces steps (1), (2), and (3)). Comparative Example 4 is a prior art product, demonstrating that the present invention improves the product's low-temperature resistance, oil resistance, and aging resistance, while reducing compression set.

[0165] Based on the above data analysis, the ethylene-propylene-vinylidene fluoride polymer preparation method provided in the examples, compared with the prior art, can improve the low-temperature resistance, oil resistance, and aging resistance of the product, and reduce compression set, thus solving the problems of poor low-temperature performance, poor oil resistance and aging resistance, and high compression set of the materials in the prior art.

[0166] The applicant declares that this invention illustrates a method for preparing an ethylene-propylene-vinylidene fluoride polymer through the above embodiments, but the invention is not limited to the above embodiments, that is, it does not mean that the invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of the raw materials for the product of this invention, additions of auxiliary components, and selection of specific methods, all fall within the protection scope and disclosure scope of this invention.

Claims

1. A method for preparing an ethylene-propylene-vinylidene fluoride polymer and its sealing components, characterized in that, The raw materials used, by weight, include: 15-50 (preferably 20-40) parts of polyethylene oligomer, 8-35 (preferably 10-30) parts of polypropylene oligomer, 3-15 (preferably 5-9) parts of hydroxyl fluorosilicone oil, 15-70 (preferably 30-50) parts of polyvinylidene fluoride, 0.05-0.20 parts of initiator and 0.5-2.0 parts of terminator, 25-35 parts of silica A380, 0.8-1.2 parts of stearic acid, 4.5-5.5 parts of zinc oxide, 2.5-3.5 parts of vulcanization accelerator TAIC, 1.0-2.0 parts of vulcanizing agent bis-25, 0.8-1.2 parts of antioxidant 4010NA and 4.5-5.5 parts of perfluoroether oil.

2. The seal according to claim 1, characterized in that, Preferably, the polyethylene oligomer is a low molecular weight homopolymer (molecular weight distribution range 1-8, preferably 1.5-6) ​​of ethylene obtained by solution polymerization, including any one or a combination of two or more of linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), and polyethylene wax. Preferably, the polypropylene oligomer is obtained by thermal cracking of high molecular weight polypropylene (molecular weight distribution range 1-8, preferably 2-7), and is a crystalline waxy or soft waxy solid, grade: WAX wax (molecular weight distribution range 2-8, preferably 2.5-6). Preferably, the hydroxyl fluorosilicone oil is polytrifluoropropylmethylsiloxane; Preferably, the polyvinylidene fluoride is a polyvinylidene fluoride-containing polymer, grade: FR916 (molecular weight distribution range 1-5, preferably 1.5-3.5); Preferably, the initiator is a peroxide initiator, including any one or a combination of two or more of benzoyl peroxide (BPO), dicumyl peroxide (DCP), tert-butyl peroxide and tert-butyl peroxide-2-ethylhexanoate (TBPO); Preferably, the terminator is a phenolic terminator, including any one or a combination of two or more of hydroquinone, p-tert-butylcatechol, and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

3. The seal according to claim 1 or 2, characterized in that, The sealing element is a sealing block or a sealing gasket.

4. A method for preparing an ethylene-propylene-vinylidene fluoride polymer and its sealing component as described in claim 1, 2, or 3, characterized in that, The preparation method specifically includes: (1) In a reactive screw extruder, polyethylene oligomer, polypropylene oligomer, hydroxyl fluorosilicone oil and polyvinylidene fluoride are mixed to obtain a first mixture; (2) In a reactive screw extruder, an initiator is added to the first mixture to carry out silanization to obtain a second mixture, which is then extruded. (3) In a closed rubber mixing mill, the second mixture and silica are fully silanized to obtain the third mixture; (4) In a closed rubber mixing mill, a terminator is added to the third mixture to terminate the reaction and obtain an ethylene-propylene-vinylidene fluoride polymer. (5) In a closed rubber mixing mill, stearic acid, zinc oxide, vulcanization accelerator, vulcanizing agent, antioxidant and plasticizer are added to ethylene-propylene-vinylidene fluoride polymer for mixing to obtain the fourth mixture. (6) The fourth mixture is vulcanized in a flat vulcanizing machine to obtain an ethylene-propylene-vinylidene fluoride polymer seal.

5. The preparation method according to claim 4, characterized in that, The preparation of the ethylene-propylene-vinylidene fluoride polymer in step (1) includes mixing using a reactive screw extruder; Preferably, the mixing temperature of the reactive screw extruder is 145–200°C; Preferably, the mixing speed of the reactive screw extruder is 15-60 rpm; Preferably, the mixing time of the reactive screw extruder is 1 to 8 minutes.

6. The preparation method according to claim 4, characterized in that, The preparation of the ethylene-propylene-vinylidene fluoride polymer in step (2) includes a silanization reaction in a reactive screw extruder; Preferably, the mixing temperature of the reactive screw extruder is 95–170°C; Preferably, the mixing speed of the reactive screw extruder is 8-60 rpm; Preferably, the mixing time of the reactive screw extruder is 1-6 minutes; Preferably, the extrusion pressure of the reaction screw is 10-22 MPa (more preferably 14-19 MPa).

7. The preparation method according to claim 4, characterized in that, The preparation of the ethylene-propylene-vinylidene fluoride polymer in step (3) includes a full silanization reaction in a closed rubber mixing mill; Preferably, the mixing temperature of the closed rubber mixing mill is 135-170℃; Preferably, the mixing speed of the closed rubber mixing mill is 35-65 rpm; Preferably, the mixing time of the closed rubber mixing mill is 2 to 6 minutes.

8. The preparation method according to claim 4, characterized in that, The preparation of the ethylene-propylene-vinylidene fluoride polymer in step (4) includes termination in a closed-loop rubber mixing mill; Preferably, the mixing temperature of the closed rubber mixing mill is 110–160°C; Preferably, the mixing speed of the closed rubber mixing mill is 15-65 rpm; Preferably, the mixing time of the closed rubber mixing mill is 2 to 8 minutes.

9. The preparation method according to claim 4, characterized in that, The preparation of the ethylene-propylene-vinylidene fluoride polymer seal in step (5) includes mixing and vulcanization molding in a closed rubber mixing mill; Preferably, the mixing temperature of the closed rubber mixing mill is 110-150℃; Preferably, the mixing speed of the closed rubber mixing mill is 15-60 rpm; Preferably, the mixing time of the closed rubber mixing mill is 2 to 8 minutes; Preferably, the temperature of the flat vulcanizing machine is 140–190°C; Preferably, the pressure of the flat vulcanizing machine is 3-15 MPa; Preferably, the vulcanization time of the flat vulcanizing machine is 15 to 50 minutes.

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