High-performance perfluoroether rubber material and preparation method thereof

Abstract

The invention discloses a high-performance perfluororubber material and a preparation method thereof, and belongs to the technical field of polymer rubber composite materials. The perfluororubber material is prepared from 100 parts by weight of perfluoroether raw rubber, 2.5-3.0 parts by weight of an organic peroxide initiator, 6.0-8.0 parts by weight of a crosslinking auxiliary agent and 30-35 parts by weight of semi-reinforced carbon black, and has excellent low temperature resistance, chemical resistance and sealing performance; the method can be applied to precision fitting fields such as semiconductors and aerospace.

Description

Technical Field

[0001] This invention belongs to the field of polymer rubber composite materials technology, and specifically relates to a perfluoroether rubber material and its preparation method. Background Technology

[0002] Perfluoroelastomer (FFKM) is a high-performance synthetic rubber with excellent chemical resistance, high-temperature resistance, and sealing properties. It is widely used in semiconductor, petrochemical, and aerospace industries. FFKM primarily uses tetrafluoroethylene (TFE) and perfluoroalkyl vinyl ethers (PFVE) as the main comonomers, and typically also contains perfluorinated bromine, iodine, and cyano compounds with high vulcanization points. Raw FFKM rubber generally cannot be used alone and often needs to be used in combination with other components such as initiators, reinforcing fillers, and processing aids. CN114181484A discloses a FFKM composition prepared from FFKM, polyimide, crosslinking agent, accelerator, and processing aids. This composition has excellent elastic modulus and is suitable for industries requiring high cleanliness, low particulate matter release, and low metal ion content, such as semiconductors, photovoltaics, and food and pharmaceuticals. CN111925615A discloses a high-strength, high-modulus perfluoroether rubber material, prepared from a perfluoroether rubber polymer, graphene, crosslinking agent, accelerator, acid scavenger, filler, and processing aid. This invention incorporates a small amount of graphene with a specific structure into the perfluoroether rubber polymer, while rationally optimizing the filler and vulcanization system. While maintaining a high rubber content in the entire formulation, the prepared rubber material exhibits excellent hardness, tensile strength, resistance to extrusion deformation, shear resistance, and resistance to rapid gas decompression. CN112457612B discloses a low-temperature resistant perfluoroether rubber composition, comprising perfluoroether rubber, liquid fluororubber elastomer, crosslinking agent, accelerator, filler, and processing aid. Rubber products obtained by heating and pressurizing the vulcanization of this composition can withstand temperatures as low as -40°C. CN116694005A discloses a high-temperature resistant perfluoroether rubber composition, the raw materials of which include perfluoroether rubber raw rubber, fillers, crosslinking agents, and processing aids. By using the high-temperature resistant perfluoroether rubber composition of this invention, the problems of uneven surface, poor thermo-oxidative aging performance, and poor thermal stability of rubber products made from domestically produced perfluoroether rubber raw rubber after vulcanization are solved. CN119192756A discloses a plasma-resistant and low-adhesion metal-free perfluoropolymer, mainly comprising: perfluoroether rubber in a peroxy vulcanization system, inorganic nitrides, peroxides, and crosslinking aids. The perfluoroether rubber in the peroxy vulcanization system is polymerized from three monomers: tetrafluoroethylene, perfluoroalkyl vinyl ether, and crosslinking point monomers. O-rings made from the metal-free perfluoropolymer prepared using this invention have excellent plasma resistance, no metal particle escape, compression set of less than 25%, and adhesion of less than 50N.

[0003] However, at present, China still relies on imports for high-end perfluoroether rubber products with strong acid and alkali resistance and ultra-low precipitation. The preparation of high-performance perfluoroether rubber is often monopolized by well-known foreign companies such as DuPont, Trelleborg, and Solvay. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention investigated the molecular structure of perfluoroether rubber. By introducing perfluoromethyl vinyl ether into the fluororubber molecular structure, oxygen atoms are introduced into the molecular chain backbone, disrupting the regularity of the macromolecular chemical structure, reducing molecular crystallinity, and improving macromolecular flexibility, thereby improving the low-temperature resistance of fluororubber. Simultaneously, a third monomer, brominated trifluoroethylene (BTTB), is introduced to prepare the perfluoroether rubber. The bromine atom (Br) introduced by this monomer can serve as a free radical crosslinking site, effectively improving the high-temperature compression set performance of the material, thus preparing a high-performance perfluoroether rubber.

[0005] This invention provides a high-performance perfluoroether rubber material, characterized in that it is prepared from the following raw and auxiliary materials in parts by weight: Perfluoroether raw rubber 100 Organic peroxide initiator 2.5~3.0 Crosslinking agent 6.0~8.0 Semi-reinforcing carbon black 30~35.

[0006] Furthermore, the perfluoroether raw rubber has the following structural formula: Furthermore, the perfluoroether raw rubber is obtained by copolymerization of four monomers: tetrafluoroethylene (TFE), perfluoromethyl vinyl ether (PMVE), a bromine-containing sulfur point monomer, and vinylidene fluoride (VF2) through a free radical crosslinking reaction. The bromine-containing sulfur point monomer is 1-bromo-3,3,4,4-tetrafluoro-1-butene (BTFB).

[0007] Furthermore, the amount of the four monomers added in the perfluoroether raw rubber is as follows: 65%~75% by weight of tetrafluoroethylene, 25%~35% by weight of perfluoromethyl vinyl ether, 0.5%~2% by weight of monomers containing bromine sulfide point, and 0.5%~0.6% by weight of vinylidene fluoride VF2.

[0008] Further, the organic peroxide initiator is one of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, dicumyl peroxide (DCP), benzoyl peroxide (BPO), and 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane.

[0009] Further, the vulcanizing agent is one of triallyl isocyanurate, triallyl cyanurate and N,N'-m-phenylenebismaleimide, preferably triallyl isocyanurate (TAIC).

[0010] This invention also provides a method for preparing a high-performance perfluoroether rubber material, comprising the following steps: (1) Plasticize 100 parts by weight of perfluoroether rubber on a two-roll mill for 2 min with a roll gap of 1.0~1.5 mm; (2) Add 2.5~3.0 parts by weight of organic peroxide vulcanizing agent, 6.0~8.0 parts by weight of crosslinking agent and 30~35 parts by weight of semi-reinforcing carbon black and other auxiliary materials in sequence and mix for 8~15 min with a roller gap of 1.5~2.0 mm. (3) The compound was passed through the rollers three times with a roller gap of 0.5~0.8 mm, each time for 7~9 min; (4) Mix for 5 minutes under the condition of 1.5~3.0 mm roller gap and then sheet out.

[0011] Furthermore, the perfluoroether rubber material is used to prepare rubber seals for use at temperatures ranging from -21°C to 295°C.

[0012] The perfluoroether rubber material prepared by this invention can be applied to precision parts fields such as semiconductors and aerospace.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: The perfluoroether rubber preparation method used in this invention reduces the interaction between fluorine atoms and improves the flexibility of the rubber under extreme conditions. This modified perfluoroether rubber can maintain its function at lower temperatures, and can be used at a maximum temperature of 295°C. Attached Figure Description

[0014] Figure 1 Photograph of perfluoroether rubber. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0016] Example 1: Preparation of perfluoroether raw rubber Using water as a medium, 70% by weight of tetrafluoroethylene (TFE), 30% by weight of perfluoromethyl vinyl ether (PMVE), and 1% by weight of a crosslinking agent were subjected to free radical-initiated emulsion binary copolymerization. The vulcanizing agent bis25 (3% by weight) was used as the initiator, sodium dihydrogen phosphate (1.2% by weight) was used as the pH adjuster, and ammonium perfluorooctanoate (0.8% by weight) was used as the surfactant; the vulcanizing agent bis25 was 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane. The reaction pressure in the copolymerization reaction is 1.5 MPa, and the polymerization temperature is 40℃.

[0017] Example 2 Using water as a medium, 65% by weight of tetrafluoroethylene (TFE), 25% by weight of perfluoromethyl vinyl ether (PMVE), 1% by weight of 1-bromo-3,3,4,4-tetrafluoro-1-butene (BTFB), 0.56% by weight of vinylidene fluoride (VF2), and 1% by weight of a co-crosslinking agent were subjected to free radical-initiated emulsion quaternary copolymerization. The remaining steps and conditions are exactly the same as in Example 1.

[0018] Example 3 Using water as a medium, 65% by weight of tetrafluoroethylene (TFE), 25% by weight of perfluoromethyl vinyl ether (PMVE), 1% by weight of 1-bromo-3,3,4,4-tetrafluoro-1-butene (BTFB) and 1% by weight of a co-crosslinking agent were subjected to free radical-initiated emulsion terpolymerization. The remaining steps and conditions are exactly the same as in Example 1.

[0019] Example 4 Using water as a medium, 65% by weight of tetrafluoroethylene (TFE), 25% by weight of perfluoromethyl vinyl ether (PMVE), 0.56% by weight of vinylidene fluoride (VF2), and 1% by weight of a co-crosslinking agent were subjected to free radical-initiated emulsion terpolymerization. The remaining steps and conditions are exactly the same as in Example 1.

[0020] Example 5: Preparation of perfluoroether rubber materials (1) 100 parts by weight of the perfluoroether rubber prepared in Example 1, or Example 2, or Example 3, or Example 4 were plasticized on a two-roll mill for 2 min with a roll gap of 1.3 mm. (2) Add 2.8 parts by weight of vulcanizing agent 25, 7.0 parts by weight of 75% triallyl isocyanurate and 33 parts by weight of semi-reinforcing carbon black and other auxiliary materials in sequence and mix for 10 min with a roller gap of 2.0 mm. (3) The compound was subjected to three thin passes with a roller gap of 0.6 mm, each for 8 min; (4) Mix for 5 minutes under a roller gap of 1.8 mm and then sheet out.

[0021] Performance testing of perfluoroether rubber materials Mechanical property testing methods: Hardness: The Shore hardness test was performed. The Shore hardness test method is GB / T531.1-2008 Test Method for Indentation Hardness of Vulcanized Rubber or Thermoplastic Rubber, Part 1.

[0022] Tensile strength: Measured according to GB / T528-2009 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber.

[0023] Compression set: The compression set was measured under normal and high temperature conditions in accordance with GB / T7759.1-2015 Determination of compression set of vulcanized rubber or thermoplastic rubber, Part 1.

[0024] Table 1. Results of Hardness and Tensile Strength Tests Sealing performance (gas permeability, sealing pressure test) Gas permeability testing was conducted according to the method for determining gas permeability of plastic films and sheets (ASTM D1434), with oxygen, nitrogen, and carbon dioxide introduced at a standard temperature of 25°C. Sealing pressure testing was also conducted according to the method for determining gas permeability of plastic films and sheets (ASTM D1434), at a standard temperature of 25°C.

[0025] Table 2. Gas permeability and sealing pressure test results Thermal performance testing and media resistance testing methods: GB / T533 Determination of density of vulcanized rubber or thermoplastic rubber.

[0026] GB / T1690 Test Method for Liquid Resistance of Vulcanized Rubber or Thermoplastic Rubber: Weigh the rubber sample to be tested and immerse it thoroughly in different solvents. Place the sample in an oven at a specific temperature according to the testing requirements for 7 days. After immersion, remove the rubber sample, wash it with deionized water, and air dry it on filter paper (1-3 hours) or dry it in an oven. Finally, weigh the sample and calculate the rate of change in mass. Among them, M o M1 is the mass of the sample before immersion, and M2 is the mass of the sample after immersion.

[0027] Test conditions: 40% sulfuric acid (85℃*7 days), 20% hydrochloric acid (50℃*7 days), 40% sodium hydroxide (85℃*7 days), 70% phosphoric acid (85℃*7 days).

[0028] Table 3. Results of thermal performance and media resistance tests Plasma corrosion resistance test: Under a pressure of 1 torr and a power of 500W, oxygen (O2) plasma was used to etch the gas. After 6 hours of etching, the surface morphology of the sealing ring was observed, and the weight change of the precipitated particles and the etching rate were calculated. The weight change was calculated using the following formula: Weight change of precipitated particles (%) = (Weight before etching - Weight after etching) / Weight before etching * 100; Etching rate (mg / h) = Weight change of etching / Unit hour.

[0029] Table 4 Results of plasma corrosion resistance test

Claims

1. A high performance perfluoroether rubber material characterized in that, It is prepared from the following raw and auxiliary materials by weight: Perfluoroether raw rubber 100 Organic peroxide initiator 2.5~3.0 Co-crosslinking agent 6.0~8.0 Semi-reinforcing carbon black 30~35.

2. A high performance perfluoroether elastomer material according to claim 1, characterized in that, The perfluoroether raw rubber has the following structural formula: The perfluoroether raw rubber is obtained by free radical crosslinking reaction of tetrafluoroethylene TFE, perfluoromethyl vinyl ether PMVE and a bromine-containing vulcanization point monomer, vinylidene fluoride VF2, wherein the bromine-containing vulcanization point monomer is 1-bromo-3,3,4,4-tetrafluoro-1-butene BTFB; The perfluoroether raw rubber contains the following monomers by weight: tetrafluoroethylene 65%~75%, perfluoromethyl vinyl ether 25%~35%, bromine-containing vulcanization point monomer 0.5%~2%, and vinylidene fluoride VF2 0.5%~0.6%.

3. A high performance perfluoroether rubber material according to any one of claims 1-2, characterized in that, In the preparation process of the perfluoroether rubber, water is used as the medium, organic peroxide is used as the initiator, sodium dihydrogen phosphate is used as the pH value regulator, and ammonium perfluorooctanoate is used as the surfactant for copolymerization reaction. The reaction pressure in the copolymerization reaction is 1.4~4.2 MPa, and the polymerization temperature is 40~100℃.

4. The high performance perfluoroether elastomer material of claim 1, wherein, The organic peroxide initiator is one of 2,5-dimethyl-2,5-bis(tert-butyl peroxy) hexane, dicumyl peroxide DCP, benzoyl peroxide BPO, and 1,1-bis(tert-butyl peroxy)-3,3,5-trimethylcyclohexane.

5. The high performance perfluoroether elastomer material of claim 1, wherein, The co-crosslinking agent is one of triallyl isocyanurate, triallyl cyanurate, and N,N'-m-phenylene bismaleimide, preferably 75% triallyl isocyanurate.

6. A method of making a high performance perfluoroether rubber material, characterized by, The method comprises the following steps: (1) 100 parts by weight of perfluoroether rubber is plasticized on a two-roll open mill for 2 min, and the roll gap is 1.0~1.5 mm; (2) 2.5~3.0 parts by weight of organic peroxide initiator, 6.0~8.0 parts by weight of co-crosslinking agent, and 30~35 parts by weight of semi-reinforcing carbon black are sequentially added and mixed for 8~15 min, and the roll gap is 1.5~2.0 mm; (3) The mixed rubber is passed through the mill 3 times with a roll gap of 0.5~0.8 mm, each time for 7~9 min; (4) The mixed rubber is mixed for 5 min with a roll gap of 1.5~3.0 mm to produce a sheet.

7. Use of a high performance perfluoroether rubber material according to any one of claims 1 to 6, characterized in that, The perfluoroether rubber material is used to prepare a rubber sealing ring used at a temperature of -21℃~295℃.

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