CN116731458B - Polytetrafluoroethylene sealing gasket and preparation method thereof - Google Patents
Polytetrafluoroethylene sealing gasket and preparation method thereof Download PDFInfo
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- CN116731458B CN116731458B CN202311027807.XA CN202311027807A CN116731458B CN 116731458 B CN116731458 B CN 116731458B CN 202311027807 A CN202311027807 A CN 202311027807A CN 116731458 B CN116731458 B CN 116731458B
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- -1 Polytetrafluoroethylene Polymers 0.000 title claims abstract description 75
- 229920001343 polytetrafluoroethylene Polymers 0.000 title claims abstract description 68
- 239000004810 polytetrafluoroethylene Substances 0.000 title claims abstract description 68
- 238000007789 sealing Methods 0.000 title claims abstract description 51
- 238000002360 preparation method Methods 0.000 title claims abstract description 18
- 239000000203 mixture Substances 0.000 claims abstract description 81
- 239000010459 dolomite Substances 0.000 claims abstract description 55
- 229910000514 dolomite Inorganic materials 0.000 claims abstract description 55
- 229910001570 bauxite Inorganic materials 0.000 claims abstract description 53
- MRELNEQAGSRDBK-UHFFFAOYSA-N lanthanum(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[La+3].[La+3] MRELNEQAGSRDBK-UHFFFAOYSA-N 0.000 claims abstract description 46
- 229920000049 Carbon (fiber) Polymers 0.000 claims abstract description 23
- 239000004917 carbon fiber Substances 0.000 claims abstract description 23
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims abstract description 23
- 229910052580 B4C Inorganic materials 0.000 claims abstract description 22
- INAHAJYZKVIDIZ-UHFFFAOYSA-N boron carbide Chemical compound B12B3B4C32B41 INAHAJYZKVIDIZ-UHFFFAOYSA-N 0.000 claims abstract description 22
- 229920002239 polyacrylonitrile Polymers 0.000 claims abstract description 17
- 239000002994 raw material Substances 0.000 claims abstract description 15
- XIUFWXXRTPHHDQ-UHFFFAOYSA-N prop-1-ene;1,1,2,2-tetrafluoroethene Chemical group CC=C.FC(F)=C(F)F XIUFWXXRTPHHDQ-UHFFFAOYSA-N 0.000 claims abstract description 10
- 239000000463 material Substances 0.000 claims abstract description 6
- 238000002156 mixing Methods 0.000 claims description 21
- 238000000498 ball milling Methods 0.000 claims description 20
- 238000010438 heat treatment Methods 0.000 claims description 20
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims description 15
- 238000001035 drying Methods 0.000 claims description 15
- 238000000748 compression moulding Methods 0.000 claims description 13
- KKYDYRWEUFJLER-UHFFFAOYSA-N 1,1,2,2,3,3,4,4,5,5,6,6,7,7,10,10,10-heptadecafluorodecyl(trimethoxy)silane Chemical compound CO[Si](OC)(OC)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)CCC(F)(F)F KKYDYRWEUFJLER-UHFFFAOYSA-N 0.000 claims description 12
- 238000005245 sintering Methods 0.000 claims description 12
- 238000006243 chemical reaction Methods 0.000 claims description 11
- 229910000831 Steel Inorganic materials 0.000 claims description 10
- 238000001816 cooling Methods 0.000 claims description 10
- 239000010959 steel Substances 0.000 claims description 10
- 238000001132 ultrasonic dispersion Methods 0.000 claims description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 10
- 238000000034 method Methods 0.000 claims description 8
- 239000007787 solid Substances 0.000 claims description 6
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 5
- 238000007873 sieving Methods 0.000 claims description 5
- 239000002002 slurry Substances 0.000 claims description 5
- 230000002195 synergetic effect Effects 0.000 abstract description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 7
- 229910052739 hydrogen Inorganic materials 0.000 description 7
- 239000001257 hydrogen Substances 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 4
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 229910052863 mullite Inorganic materials 0.000 description 3
- 239000012071 phase Substances 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000004146 energy storage Methods 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 229910052755 nonmetal Inorganic materials 0.000 description 2
- 238000011056 performance test Methods 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 239000010425 asbestos Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 229910052593 corundum Inorganic materials 0.000 description 1
- 239000010431 corundum Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 229910052895 riebeckite Inorganic materials 0.000 description 1
- 239000003566 sealing material Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L27/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers
- C08L27/02—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L27/12—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
- C08L27/18—Homopolymers or copolymers or tetrafluoroethene
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
- C08K3/20—Oxides; Hydroxides
- C08K3/22—Oxides; Hydroxides of metals
- C08K2003/221—Oxides; Hydroxides of metals of rare earth metal
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
- C08K3/20—Oxides; Hydroxides
- C08K3/22—Oxides; Hydroxides of metals
- C08K2003/2227—Oxides; Hydroxides of metals of aluminium
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K2201/00—Specific properties of additives
- C08K2201/011—Nanostructured additives
Abstract
The invention belongs to the technical field of polytetrafluoroethylene material preparation, and particularly relates to a polytetrafluoroethylene sealing gasket and a preparation method thereof. The polytetrafluoroethylene sealing gasket comprises the following raw materials in percentage by mass: 72-74% of polytetrafluoroethylene, 3-5% of poly perfluoroethylene propylene, 3.2-3.6% of polyacrylonitrile, 10.3-13.5% of a mixture of modified bauxite and dolomite, 1-2% of boron carbide, 3-4% of nano lanthanum oxide and 2-3% of carbon fiber. According to the polytetrafluoroethylene sealing gasket disclosed by the invention, the raw materials are matched and synergistic, so that the prepared polytetrafluoroethylene gasket has excellent creep resistance, cold flow resistance, rebound resilience, wear resistance and sealing performance.
Description
Technical Field
The invention belongs to the technical field of polytetrafluoroethylene material preparation, and particularly relates to a polytetrafluoroethylene sealing gasket and a preparation method thereof.
Background
The hydrogen has the characteristics of storability, high energy density, zero pollution in the using process and zero carbon emission, is one of main carriers of renewable energy sources, has the performance of power and energy storage, and is irreplaceable as a carbon-free industrial raw material. "Green hydrogen" will be one of the main ways to address large-scale, long-cycle energy storage and diverse end uses in renewable energy conversion. It is known that ensuring safe operation of the "green hydrogen" production facility is a necessary condition for the production of "green hydrogen".
The gasket has a sealing effect in industrial production. The sealing gasket is made of metal and non-metal plates and is manufactured by cutting, stamping and cutting process, and is used for sealing connection between pipelines and parts of equipment and machines. It is divided into metal and nonmetal gaskets. The metal sealing gasket is provided with copper, iron, stainless steel gaskets and the like; the nonmetallic sealing gasket comprises rubber, asbestos, paper gasket, polytetrafluoroethylene gasket and the like.
The existing polytetrafluoroethylene gasket is mostly prepared by mixing polytetrafluoroethylene with various auxiliary materials, and the combination of the material formulas and the manufacturing method are unreasonable, so that the comprehensive performance of the gasket is limited, and the gasket is particularly characterized in that the gasket is easy to cold flow and creep to cause liquid leakage of a groove body under the conditions of high temperature and high pressure and intermittent startup in the use process of green hydrogen manufacturing equipment, thereby influencing the normal operation of the green hydrogen manufacturing equipment and causing explosion in severe cases.
Therefore, it is necessary to explore a novel polytetrafluoroethylene sealing gasket to improve cold flow resistance, thereby ensuring normal operation of "green hydrogen" production equipment.
Disclosure of Invention
The purpose of the invention is that: the polytetrafluoroethylene sealing gasket has the characteristics of good creep resistance and good cold flow resistance; the invention also provides a preparation method of the composite.
The polytetrafluoroethylene sealing gasket provided by the invention comprises the following raw materials in percentage by mass: 72-74% of polytetrafluoroethylene, 3-5% of poly perfluoroethylene propylene, 3.2-3.6% of polyacrylonitrile, 10.3-13.5% of a mixture of modified bauxite and dolomite, 1-2% of boron carbide, 3-4% of nano lanthanum oxide and 2-3% of carbon fiber; wherein: the preparation method of the mixture of the modified bauxite and the dolomite comprises the following steps: mixing the bauxite and dolomite mixture, water and steel balls, performing ball milling, drying at 110-115 ℃ for 3-4h, heating to 1000-1050 ℃ at the rate of 8-10 ℃/min, preserving heat for 30-35min, heating to 1200-1250 ℃ at the rate of 6-8 ℃/min, preserving heat for 40-45min, heating to 1320-1350 ℃ at the rate of 3-4 ℃/min, preserving heat for 50-60min, cooling to room temperature, crushing, and sieving with a 325-mesh sieve to prepare the modified bauxite and dolomite mixture.
Preferably, the polytetrafluoroethylene sealing gasket provided by the invention comprises the following raw materials in percentage by mass: 73% of polytetrafluoroethylene, 4% of perfluoroethylene propylene, 3.6% of polyacrylonitrile, 12.4% of modified bauxite and dolomite, 1.5% of boron carbide, 3% of nano lanthanum oxide and 2.5% of carbon fiber.
Wherein:
the mass ratio of bauxite to dolomite is 97-100:3-3.3.
The mass ratio of the bauxite to the dolomite mixture to the water to the steel balls is 1:4-6:18-20.
The ball milling time is 20-24h.
The preparation method of the polytetrafluoroethylene sealing gasket provided by the invention comprises the following steps:
(1) Preparing a mixture of modified bauxite and dolomite;
(2) Uniformly mixing the mixture of the modified bauxite and the dolomite prepared in the step (1), boron carbide, nano lanthanum oxide and carbon fiber, adding the mixture into absolute ethyl alcohol for ultrasonic dispersion, then adding heptadecafluorodecyl trimethoxy silane into the system, simultaneously adding acetic acid to adjust the pH value of the reaction system to 5-6, reacting at 53-55 ℃ for 2.3-2.5 hours, centrifuging the slurry after the reaction is finished, and drying the obtained solid at 85-88 ℃ for 36-40 hours;
(3) Drying a mixture of polytetrafluoroethylene, perfluoroethylene propylene and polyacrylonitrile at 80-83 ℃ for 6-8 hours, then ball-milling and uniformly mixing the mixture with the mixture prepared in the step (2) to prepare a mixture, pouring the mixture into a mold for compression molding, finally heating the mixture to 370-373 ℃ for high-temperature sintering for 3-4 hours, and cooling the mixture to room temperature at a speed of 15.5-16.0 ℃/h after the sintering is finished to prepare the polytetrafluoroethylene sealing gasket.
Wherein:
the ultrasonic dispersion time in the step (2) is 1.2-1.5h.
The mass of the heptadecafluorodecyl trimethoxysilane in the step (2) is 4-4.5% of the sum of the mass of the mixture of modified bauxite and dolomite, the mass of boron carbide, the mass of nano lanthanum oxide and the mass of carbon fiber.
In the step (3), the ball milling and mixing rotational speed is 300-320r/min, and the time is 16-18h.
The pressure of the compression molding in the step (3) is 45-48MPa, and the time of the compression molding is 15-20min.
Compared with the prior art, the invention has the following beneficial effects:
(1) According to the polytetrafluoroethylene sealing gasket, polytetrafluoroethylene is used as a main raw material, and the mixture of perfluoroethylene propylene, polyacrylonitrile, modified bauxite and dolomite, the mixture of boron carbide, nanometer lanthanum oxide and carbon fiber are additionally added, so that the raw materials interact with each other, and a synergistic effect relationship is achieved. The addition of the poly (perfluoroethylene propylene) and the polyacrylonitrile cooperate with each other, so that the wear rate of the prepared polytetrafluoroethylene sealing gasket under low load is reduced, the polyacrylonitrile is required to be added in order to offset the increase of the friction coefficient of the sealing gasket caused by the addition of the poly (perfluoroethylene propylene), the binding force of the transfer film and the grinding surface is enhanced to form a complete and solid friction transfer film, and the friction action is always carried out between the transfer film and the matrix, so that the friction coefficient of the polytetrafluoroethylene sealing gasket is maintained at a lower level, and the creep relaxation performance of the prepared polytetrafluoroethylene sealing gasket is improved. The mixture of the modified bauxite and the dolomite is that the bauxite and the dolomite are compounded according to a specific proportion and then are calcined at a high temperature to prepare acicular mullite, wherein the dolomite plays a role of a sintering aid, and a silicon-rich liquid phase is generated in the dolomite after being calcined at a high temperature of 1320-1350 ℃, so that the generated liquid phase contacts with a corundum phase to promote the formation of an acicular secondary mullite phase, and the strength of powder is greatly improved. The high-strength powder with the mullite phase structure is compounded with boron carbide for use, so that the hardness of the prepared polytetrafluoroethylene gasket is improved. The increased hardness of the polytetrafluoroethylene gasket can, to some extent, enhance the ability of the sealing material surface to resist mechanical pressure. In addition, in order to ensure the compression resilience performance of the prepared polytetrafluoroethylene gasket, a small amount of carbon fiber and nano lanthanum oxide are added, and the carbon fiber and the nano lanthanum oxide are compounded for use, so that when the polytetrafluoroethylene gasket is elastically or plastically deformed, the defect of the sealing surface is filled, and the elastic compensation is carried out, so that the sealing capability of the polytetrafluoroethylene gasket is maintained.
(2) According to the polytetrafluoroethylene sealing gasket disclosed by the invention, the raw materials are matched and synergistic, so that the prepared polytetrafluoroethylene gasket has excellent creep resistance, cold flow resistance, rebound resilience, wear resistance and sealing performance.
(3) According to the preparation method of the polytetrafluoroethylene sealing gasket, firstly, a mixture of modified bauxite and dolomite is prepared, and then the mixture of the modified bauxite and the dolomite, boron carbide, nanometer lanthanum oxide and carbon fiber is modified by adopting heptadecafluorodecyl trimethoxy silane, so that on one hand, the surface energy of the mixture is reduced, the dispersibility in a polytetrafluoroethylene matrix is improved, and the aggregation is reduced; on the other hand, the heptadecafluorodecyl trimethoxy silane is better compatible with polytetrafluoroethylene, the defects at the interface are reduced, and finally the polytetrafluoroethylene sealing gasket is prepared through mould pressing and sintering.
Detailed Description
The invention is further described below with reference to examples.
Example 1
The polytetrafluoroethylene sealing gasket of the embodiment 1 comprises the following raw materials in percentage by mass: 73% of polytetrafluoroethylene, 4% of perfluoroethylene propylene, 3.6% of polyacrylonitrile, 12.4% of modified bauxite and dolomite, 1.5% of boron carbide, 3% of nano lanthanum oxide and 2.5% of carbon fiber; wherein: the preparation method of the mixture of the modified bauxite and the dolomite comprises the following steps: mixing the bauxite and dolomite mixture, water and steel balls, performing ball milling, drying at 113 ℃ for 3.5 hours, then heating to 1030 ℃ at a speed of 9 ℃/min, preserving heat for 33 minutes, heating to 1230 ℃ at a speed of 7 ℃/min, preserving heat for 43 minutes, heating to 1335 ℃ at a speed of 3.5 ℃/min, preserving heat for 55 minutes, finally cooling to room temperature, crushing, and sieving with a 325-mesh sieve to obtain the modified bauxite and dolomite mixture.
Wherein:
the mass ratio of bauxite to dolomite is 97:3.
The mass ratio of the bauxite to dolomite mixture to the water to the steel balls is 1:5:19.
The ball milling time was 22h.
The preparation method of the polytetrafluoroethylene sealing gasket of the embodiment 1 comprises the following steps:
(1) Preparing a mixture of modified bauxite and dolomite;
(2) Uniformly mixing the mixture of the modified bauxite and the dolomite prepared in the step (1), boron carbide, nano lanthanum oxide and carbon fiber, adding the mixture into absolute ethyl alcohol for ultrasonic dispersion, adding heptadecafluorodecyl trimethoxy silane into the system, simultaneously adding acetic acid to adjust the pH value of the reaction system to 6, reacting for 2.4 hours at 54 ℃, centrifuging the slurry after the reaction is finished, and drying the obtained solid at 87 ℃ for 38 hours;
(3) And (3) drying the mixture of polytetrafluoroethylene, perfluoroethylene propylene and polyacrylonitrile at 82 ℃ for 7 hours, then ball-milling and uniformly mixing the mixture with the mixture prepared in the step (2) to prepare a mixture, pouring the mixture into a mould for compression molding, finally heating to 372 ℃ for high-temperature sintering for 3.5 hours, and cooling to room temperature at a speed of 15.7 ℃/h after sintering is finished to prepare the polytetrafluoroethylene sealing gasket.
Wherein:
the ultrasonic dispersion time in the step (2) is 1.4h.
The mass of heptadecafluorodecyl trimethoxysilane in the step (2) is 4.5 percent of the sum of the mass of the mixture of modified bauxite and dolomite, boron carbide, nanometer lanthanum oxide and carbon fiber.
In the step (3), the ball milling and mixing rotating speed is 310r/min, and the time is 17h.
The pressure of the compression molding in the step (3) is 47MPa, and the time of the compression molding is 18min.
Example 2
The polytetrafluoroethylene sealing gasket of the embodiment 2 comprises the following raw materials in percentage by mass: 72% of polytetrafluoroethylene, 5% of perfluoroethylene propylene, 3.5% of polyacrylonitrile, 10.5% of modified bauxite and dolomite mixture, 2% of boron carbide, 4% of nano lanthanum oxide and 3% of carbon fiber; wherein: the preparation method of the mixture of the modified bauxite and the dolomite comprises the following steps: mixing the bauxite and dolomite mixture, water and steel balls, performing ball milling, drying at 110 ℃ for 3 hours, then heating to 1000 ℃ at the rate of 8 ℃/min, preserving heat for 30min, heating to 1200 ℃ at the rate of 6 ℃/min, preserving heat for 40min, heating to 1320 ℃ at the rate of 3 ℃/min, preserving heat for 50min, finally cooling to room temperature, crushing, and sieving with a 325-mesh sieve to obtain the modified bauxite and dolomite mixture.
Wherein:
the mass ratio of bauxite to dolomite is 100:3.3.
The mass ratio of the bauxite to dolomite mixture to the water to the steel balls is 1:4:18.
The ball milling time is 20h.
The preparation method of the polytetrafluoroethylene sealing gasket of the embodiment 2 comprises the following steps:
(1) Preparing a mixture of modified bauxite and dolomite;
(2) Uniformly mixing the mixture of the modified bauxite and the dolomite prepared in the step (1), boron carbide, nano lanthanum oxide and carbon fiber, adding the mixture into absolute ethyl alcohol for ultrasonic dispersion, then adding heptadecafluorodecyl trimethoxy silane into the system, simultaneously adding acetic acid to adjust the pH value of the reaction system to 5.5, reacting for 2.3 hours at 53 ℃, centrifuging the slurry after the reaction is finished, and drying the obtained solid at 85 ℃ for 36 hours;
(3) And (3) drying the mixture of polytetrafluoroethylene, poly (perfluoroethylene) propylene and polyacrylonitrile at 80 ℃ for 6 hours, then ball-milling and uniformly mixing the mixture with the mixture prepared in the step (2) to prepare a mixture, pouring the mixture into a mould for compression molding, finally heating to 370 ℃ for high-temperature sintering for 4 hours, and cooling to room temperature at a speed of 15.5 ℃/h after sintering is finished to prepare the polytetrafluoroethylene sealing gasket.
Wherein:
the ultrasonic dispersion time in the step (2) is 1.5h.
The mass of heptadecafluorodecyl trimethoxysilane in the step (2) is 4 percent of the sum of the mass of the mixture of modified bauxite and dolomite, boron carbide, nanometer lanthanum oxide and carbon fiber.
In the step (3), the ball milling mixing rotating speed is 300r/min, and the time is 16h.
The pressure of the compression molding in the step (3) is 45MPa, and the time of the compression molding is 20min.
Example 3
The polytetrafluoroethylene sealing gasket of the embodiment 3 comprises the following raw materials in percentage by mass: 74% of polytetrafluoroethylene, 3% of perfluoroethylene propylene, 3.2% of polyacrylonitrile, 13.3% of modified bauxite and dolomite mixture, 1% of boron carbide, 3.5% of nano lanthanum oxide and 2% of carbon fiber; wherein: the preparation method of the mixture of the modified bauxite and the dolomite comprises the following steps: mixing the bauxite and dolomite mixture, water and steel balls, performing ball milling, drying at 115 ℃ for 4 hours, then heating to 1050 ℃ at a rate of 10 ℃/min, preserving heat for 35min, heating to 1250 ℃ at a rate of 8 ℃/min, preserving heat for 45min, heating to 1350 ℃ at a rate of 4 ℃/min, preserving heat for 60min, finally cooling to room temperature, crushing, and sieving with a 325-mesh sieve to obtain the modified bauxite and dolomite mixture.
Wherein:
the mass ratio of bauxite to dolomite is 99:3.1.
The mass ratio of the bauxite to dolomite mixture to the water to the steel balls is 1:6:20.
The ball milling time was 24 hours.
The preparation method of the polytetrafluoroethylene sealing gasket in the embodiment 3 comprises the following steps:
(1) Preparing a mixture of modified bauxite and dolomite;
(2) Uniformly mixing the mixture of the modified bauxite and the dolomite prepared in the step (1), boron carbide, nano lanthanum oxide and carbon fiber, adding the mixture into absolute ethyl alcohol for ultrasonic dispersion, adding heptadecafluorodecyl trimethoxy silane into the system, simultaneously adding acetic acid to adjust the pH value of the reaction system to 5, reacting for 2.5 hours at 55 ℃, centrifuging the slurry after the reaction is finished, and drying the obtained solid at 88 ℃ for 40 hours;
(3) Drying a mixture of polytetrafluoroethylene, poly (perfluoroethylene) propylene and polyacrylonitrile at 83 ℃ for 8 hours, then ball-milling and uniformly mixing the mixture with the mixture prepared in the step (2) to prepare a mixture, pouring the mixture into a mould for compression molding, finally heating to 373 ℃ for high-temperature sintering for 3 hours, and cooling to room temperature at a speed of 16.0 ℃/h after sintering is finished to prepare the polytetrafluoroethylene sealing gasket.
Wherein:
the ultrasonic dispersion time in the step (2) is 1.2h.
The mass of heptadecafluorodecyl trimethoxysilane in the step (2) is 4.3 percent of the sum of the mass of the mixture of modified bauxite and dolomite, boron carbide, nanometer lanthanum oxide and carbon fiber.
In the step (3), the ball milling mixing rotating speed is 320r/min, and the time is 18h.
The pressure of the press molding in the step (3) is 48MPa, and the time of the press molding is 15min.
Comparative example 1
The preparation method of the polytetrafluoroethylene sealing gasket in comparative example 1 is the same as that in example 1, except that the raw material composition is different. The polytetrafluoroethylene sealing gasket of the comparative example 1 comprises the following raw materials in percentage by mass: 85.4% of polytetrafluoroethylene, 4% of perfluoroethylene propylene, 3.6% of polyacrylonitrile, 1.5% of boron carbide, 3% of nano lanthanum oxide and 2.5% of carbon fiber.
The polytetrafluoroethylene sealing gaskets prepared in examples 1-3 and comparative example 1 were subjected to performance tests, and the results are shown in table 1 below:
TABLE 1 polytetrafluoroethylene gasket performance test results
Claims (9)
1. A polytetrafluoroethylene sealing gasket, characterized in that: the material consists of the following raw materials in percentage by mass: 72-74% of polytetrafluoroethylene, 3-5% of poly perfluoroethylene propylene, 3.2-3.6% of polyacrylonitrile, 10.3-13.5% of a mixture of modified bauxite and dolomite, 1-2% of boron carbide, 3-4% of nano lanthanum oxide and 2-3% of carbon fiber; wherein: the preparation method of the mixture of the modified bauxite and the dolomite comprises the following steps: mixing a bauxite and dolomite mixture, water and a steel ball, performing ball milling, drying at 110-115 ℃ for 3-4h, heating to 1000-1050 ℃ at the rate of 8-10 ℃/min, preserving heat for 30-35min, heating to 1200-1250 ℃ at the rate of 6-8 ℃/min, preserving heat for 40-45min, heating to 1320-1350 ℃ at the rate of 3-4 ℃/min, preserving heat for 50-60min, cooling to room temperature, crushing, and sieving with a 325-mesh sieve to prepare a modified bauxite and dolomite mixture; wherein: the mass ratio of bauxite to dolomite is 97-100:3-3.3.
2. The polytetrafluoroethylene sealing gasket as set forth in claim 1 wherein: the material consists of the following raw materials in percentage by mass: 73% of polytetrafluoroethylene, 4% of perfluoroethylene propylene, 3.6% of polyacrylonitrile, 12.4% of modified bauxite and dolomite, 1.5% of boron carbide, 3% of nano lanthanum oxide and 2.5% of carbon fiber.
3. The polytetrafluoroethylene sealing gasket as set forth in claim 1 wherein: the mass ratio of the bauxite to the dolomite mixture to the water to the steel balls is 1:4-6:18-20.
4. The polytetrafluoroethylene sealing gasket as set forth in claim 1 wherein: the ball milling time is 20-24h.
5. A method for preparing the polytetrafluoroethylene sealing gasket of claim 1, wherein: the method comprises the following steps:
(1) Preparing a mixture of modified bauxite and dolomite;
(2) Uniformly mixing the mixture of the modified bauxite and the dolomite prepared in the step (1), boron carbide, nano lanthanum oxide and carbon fiber, adding the mixture into absolute ethyl alcohol for ultrasonic dispersion, then adding heptadecafluorodecyl trimethoxy silane into the system, simultaneously adding acetic acid to adjust the pH value of the reaction system to 5-6, reacting at 53-55 ℃ for 2.3-2.5 hours, centrifuging the slurry after the reaction is finished, and drying the obtained solid at 85-88 ℃ for 36-40 hours;
(3) Drying a mixture of polytetrafluoroethylene, perfluoroethylene propylene and polyacrylonitrile at 80-83 ℃ for 6-8 hours, then ball-milling and uniformly mixing the mixture with the mixture prepared in the step (2) to prepare a mixture, pouring the mixture into a mold for compression molding, finally heating the mixture to 370-373 ℃ for high-temperature sintering for 3-4 hours, and cooling the mixture to room temperature at a speed of 15.5-16.0 ℃/h after the sintering is finished to prepare the polytetrafluoroethylene sealing gasket.
6. The method for preparing the polytetrafluoroethylene sealing gasket according to claim 5, wherein: the ultrasonic dispersion time in the step (2) is 1.2-1.5h.
7. The method for preparing the polytetrafluoroethylene sealing gasket according to claim 5, wherein: the mass of the heptadecafluorodecyl trimethoxysilane in the step (2) is 4-4.5% of the sum of the mass of the mixture of modified bauxite and dolomite, the mass of boron carbide, the mass of nano lanthanum oxide and the mass of carbon fiber.
8. The method for preparing the polytetrafluoroethylene sealing gasket according to claim 5, wherein: in the step (3), the ball milling and mixing rotational speed is 300-320r/min, and the time is 16-18h.
9. The method for preparing the polytetrafluoroethylene sealing gasket according to claim 5, wherein: the pressure of the compression molding in the step (3) is 45-48MPa, and the time of the compression molding is 15-20min.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07138440A (en) * | 1993-11-17 | 1995-05-30 | Sumitomo Chem Co Ltd | Thermoplastic fluororesin composition and jig for semiconductor production process |
| CN1990538A (en) * | 2005-12-28 | 2007-07-04 | 中国科学技术大学 | High-wearing polytetrafluoroethylene composite material and preparing method thereof |
| CN105199280A (en) * | 2015-11-10 | 2015-12-30 | 扬州大学 | Mullite and carbon fiber synergically-modified PTFE composite and preparation method thereof |
| CN111362672A (en) * | 2020-03-24 | 2020-07-03 | 合肥汉甲陶瓷科技有限公司 | Preparation process of bauxite-based ceramic filler |
-
2023
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07138440A (en) * | 1993-11-17 | 1995-05-30 | Sumitomo Chem Co Ltd | Thermoplastic fluororesin composition and jig for semiconductor production process |
| CN1990538A (en) * | 2005-12-28 | 2007-07-04 | 中国科学技术大学 | High-wearing polytetrafluoroethylene composite material and preparing method thereof |
| CN105199280A (en) * | 2015-11-10 | 2015-12-30 | 扬州大学 | Mullite and carbon fiber synergically-modified PTFE composite and preparation method thereof |
| CN111362672A (en) * | 2020-03-24 | 2020-07-03 | 合肥汉甲陶瓷科技有限公司 | Preparation process of bauxite-based ceramic filler |
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