Fluororubber material as well as preparation method and application thereof

Abstract

The invention discloses a fluororubber material and a preparation method and application thereof, the fluororubber material comprises the following raw materials by mass: 100 parts of fluororubber raw rubber, 25-35 parts of thermal cracking carbon black N990, 5-15 parts of fast extruding furnace black N550, 3-6 parts of a heat resistant agent, 1.5-3 parts of a vulcanizing agent, 2.5-4 parts of a vulcanizing aid triallyl isocyanurate, 1-2 parts of a processing aid, and 10-50 parts of a carbon nanotube-ethanol mixed solution; the rubber material with excellent high temperature resistance, high pressure resistance, low compression set and high strength retention rate performance is prepared through the synergistic effect of four core mechanisms of intrinsic characteristics of the base material, synergistic reinforcement of the filler, optimization of a vulcanization cross-linked network and precise modification of the carbon nanotubes and mutual support of the mechanisms; the fluororubber sealing ring material for the ultra-deep well logging equipment is suitable for the severe working conditions of the ultra-deep well of 8000-10000 meters, the temperature of 200 DEG C or above and the pressure of 180 MPa or above.

Description

Technical Field

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

[0002] Rubber sealing rings for well logging equipment are key sealing components. Their main function is to prevent high-temperature downhole media from leaking into the casing due to high pressure, thus preventing damage to the precision instruments inside and ensuring the normal operation of the logging equipment and the accuracy of the test data. As oil wells become increasingly deep, downhole temperatures and pressures rise. When the depth reaches below 8000 meters, the temperature rises above 200°C and the pressure increases to above 180 MPa. Combined with the downhole environment containing oil, mud, and hydrogen sulfide, extremely stringent requirements are placed on the sealing ring materials for their resistance to high temperatures, high pressures, and corrosive media.

[0003] Currently, domestically produced fluororubber sealing rings are mostly used in logging equipment for wells ≤7000 meters deep, with a maximum operating temperature of 180℃ and a maximum pressure of 140MPa. For ultra-deep wells exceeding 8000 meters, existing domestically produced fluororubber sealing rings often fail due to issues such as product breakage and large compression set during use. The main reasons are: the fluororubber material used in domestically produced products has low strength retention at high temperatures, large compression set at corresponding high temperatures, and short service life. Therefore, domestically produced fluororubber sealing rings for ultra-deep well logging equipment are currently primarily imported. Summary of the Invention

[0004] To address the shortcomings of the existing technology, the present invention aims to provide a fluororubber material, its preparation method, and its application. This fluororubber material exhibits high strength retention under high temperature conditions, low compression set, and excellent high-temperature and high-pressure resistance. The sealing rings prepared from this material can meet the requirements of logging equipment for sealing performance and service life in ultra-deep wells ranging from 8,000 meters to 10,000 meters.

[0005] This invention is achieved through the following technical solution: A fluororubber material, comprising, by weight parts: 100 parts of fluororubber raw rubber, 25-35 parts of pyrolytic carbon black N990, 5-15 parts of fast-extrusion carbon black N550, 3-6 parts of heat resistant agent, 1.5-3 parts of vulcanizing agent, 2.5-4 parts of vulcanizing aid triallyl isocyanurate, 1-2 parts of processing aid, and 10-50 parts of carbon nanotube-ethanol mixture.

[0006] The present invention also has the following technical features: Preferably, the fluororubber raw rubber is fluororubber raw rubber or perfluoroether raw rubber with a fluorine content of ≥69%.

[0007] Preferably, the heat-resistant agent includes any one of calcium oxide, magnesium oxide, and zinc oxide.

[0008] Preferably, the vulcanizing agent includes any one of 2,5-dimethyl-2,5-di-tert-butylperoxyethane, dicumyl peroxide, and bis-tert-butylperoxyisopropylbenzene.

[0009] Preferably, the processing aids include one or more of WS280, carnauba wax, HT-290, and fluorinated wax.

[0010] Preferably, the carbon nanotube-ethanol mixture is prepared by uniformly mixing anhydrous ethanol and multi-walled carbon nanotubes at a mass ratio of (300~600):(1~1.5).

[0011] This invention also protects a method for preparing the fluororubber material as described above, comprising the following steps: Step 1: Add the weighed pyrolysis carbon black N990 and fast extrusion carbon black N550 to the weighed fluororubber raw rubber, and pass it through a two-roll mill 5 to 10 times to obtain the masterbatch. Step 2: Add the carbon nanotubes to the weighed anhydrous ethanol in three portions according to the proportion, stirring while adding. After adding, stir for 30-60 minutes to obtain a carbon nanotube-ethanol mixture. Step 3: Place the masterbatch obtained in Step 1 on a two-roll mill and pass it through the mill. Apply the weighed carbon nanotube-ethanol mixture from Step 2 evenly to the surface of the masterbatch. Apply the mixture every 2 to 3 minutes until the carbon nanotube-ethanol mixture is completely applied. Pass through the mill 15 to 20 times. Step 4: The masterbatch obtained in Step 3 is processed into thin rubber sheets with a thickness of 1~1.5mm, and the thin rubber sheets are dried in a constant temperature oven. Step 5: Mix the dried film obtained in Step 4 with the heat resistant agent and processing aid in proportion on a two-roll mill, and pass through the mill 5 to 8 times. Step 6: Mix the masterbatch obtained in Step 5 with vulcanizing agent and vulcanizing aid in proportion on a two-roll mill, pass through a thin mill 5 to 8 times, degas and sheet to obtain the compound. Step 7: The mixture described in Step 6 is molded and vulcanized at 170~180℃ for 10~20 minutes, and then vulcanized at a constant temperature in a constant temperature oven at 230℃ for 10 hours to obtain fluororubber material.

[0012] Preferably, the roller gap during thin-pass operation in steps 1, 3, 5, and 6 is 0.7~1mm, and the roller temperature is 60~80℃.

[0013] Preferably, the drying temperature in step 4 is 70~80℃ and the drying time is 4~6 h.

[0014] This invention also protects the application of a fluororubber material as described above in fluororubber sealing rings for ultra-deep well logging equipment.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention utilizes four core mechanisms—intrinsic properties of matrix materials, synergistic reinforcement of fillers, optimization of vulcanization crosslinking networks, and precise modification of carbon nanotubes—to synergistically produce a rubber material with excellent resistance to high temperature, high pressure, low compression set, and high strength retention. This material is suitable for use as a fluororubber sealing ring in ultra-deep well logging equipment, adaptable to the harsh working conditions of 200°C and 180MPa in ultra-deep wells of 8000~10000 meters. This invention selects fluororubber or perfluoroether rubber with a fluorine content of ≥69% as the matrix. Its molecular structure provides the core intrinsic advantages for performance. It uses thermally decomposed carbon black N990 + fast extrusion carbon black N550 as a compound filler. The two complement each other in structure and function, and improve the mechanical properties and high-temperature dimensional stability of the material from the filler-rubber interface. This invention utilizes multi-walled carbon nanotubes, which possess small size, surface, and thermal conductivity effects, to form a three-dimensional nano-network framework within a fluororubber matrix. This enhances the material's room-temperature / high-temperature tensile strength, restricts the intense thermal motion and slippage of rubber molecular chains at high temperatures, thereby improving the material's high-temperature strength retention and reducing compression set. Carbon nanotubes exhibit excellent thermal conductivity; after dispersion, they form thermal pathways within the rubber matrix, rapidly conducting and uniformly dispersing the localized high temperatures from ultra-deep wells. This prevents localized thermal degradation and cross-linking network destruction due to overheating, delaying thermal aging and further ensuring performance stability at high temperatures. The nano-framework of carbon nanotubes possesses high rigidity and exhibits no significant expansion at high temperatures. Their three-dimensional distribution within the rubber constrains the high-temperature volume expansion of the rubber matrix, particularly addressing the high high-temperature expansion rate of perfluoroether rubber. This constraint effect is even more significant, ensuring the dimensional accuracy of the sealing ring at high temperatures and preventing seal failure due to excessive sealing gaps caused by expansion. This invention achieves uniform dispersion of carbon nanotubes by coating a carbon nanotube-ethanol mixture and applying it thinly, thus avoiding the agglomeration problem of traditional mechanical blending. This invention utilizes a peroxide vulcanization system formed by a vulcanizing agent and vulcanization auxiliaries, combined with the thermal stabilizing effect of a heat-resistant agent, to construct a stable rubber crosslinking network, thereby improving the high-temperature resistance of the material from a chemical perspective. The addition of processing aids such as WS280, palm wax, and fluorowax in this invention does not directly improve performance, but rather ensures uniform dispersion of fillers such as carbon black, carbon nanotubes, and heat-resistant agents in fluororubber by reducing interfacial friction during the open milling process. At the same time, it avoids the breakage of rubber molecular chains due to excessive shear force during the open milling process, thus ensuring the integrity of the matrix molecular chains. Furthermore, these processing aids have good compatibility with fluororubber, do not precipitate at high temperatures, and do not damage the cross-linking network and filler-rubber interface, achieving "improved processability without sacrificing performance." Detailed Implementation

[0016] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0017] Example 1 This embodiment provides a fluororubber material, the raw materials of which, by mass parts, include: The composition includes 100 parts fluororubber, 30 parts thermally decomposed carbon black N990, 10 parts rapid extrusion carbon black N550, 5 parts heat resistant agent, 2 parts vulcanizing agent, 4 parts vulcanizing aid, 1 part processing aid, and 30 parts carbon nanotube-ethanol mixture. The fluororubber has a fluorine content of 70.2%, the heat resistant agent is zinc oxide, the vulcanizing agent is 2,5-dimethyl-2,5-di-tert-butylperoxyethane, the vulcanizing aid is triallyl isocyanurate, and the processing aid is HT-290. The carbon nanotube-ethanol mixture is prepared by uniformly mixing anhydrous ethanol and multi-walled carbon nanotubes at a mass ratio of 500:1.2.

[0018] The preparation method of the fluororubber material in this embodiment includes the following steps: Step 1: Add the weighed pyrolysis carbon black N990 and fast extrusion carbon black N550 to the weighed fluororubber raw rubber, and pass it through a two-roll mill with a roller temperature of 60℃ and a roller gap of 0.7mm 6 times to obtain the masterbatch. Step 2: Add the carbon nanotubes to the anhydrous ethanol weighed in proportion in three portions, stirring while adding. After adding all the carbon nanotubes, stir for 40 minutes to obtain a carbon nanotube-ethanol mixture. Step 3: Place the masterbatch obtained in Step 1 on a two-roll mill, and evenly brush the weighed carbon nanotube-ethanol mixture from Step 2 onto the surface of the masterbatch. Brush once every 2 minutes until the carbon nanotube-ethanol mixture is completely brushed. Pass through the mill 15 times. The roller temperature during the thin pass is 70°C and the roller gap is 0.7 mm. Step 4: The masterbatch obtained in Step 3 is processed into a thin sheet with a thickness of 1 mm, and the sheet is dried in a constant temperature oven at 70°C for 5 hours. Step 5: Mix the dried film obtained in Step 4 with the heat resistant agent and processing aid in proportion on an open mill, and pass it through the mill 6 times. The roller temperature during the thin pass is 70°C and the roller gap is 0.7mm. Step 6: Mix the masterbatch obtained in Step 5 with vulcanizing agent and vulcanizing aid in proportion on a two-roll mill, then pass it through a two-roll mill with a roll gap of 0.7 mm and a roll temperature of 60°C 8 times to degas and sheet out to obtain the compound. Step 7: The mixture described in Step 6 is molded and vulcanized at 170°C for 20 minutes, and then vulcanized at a constant temperature of 230°C in a constant temperature oven for 10 hours to obtain fluororubber material.

[0019] Example 2 This embodiment provides a fluororubber material. The raw materials, by mass parts, include: 100 parts fluororubber, 35 parts thermally decomposed carbon black N990, 5 parts rapid extrusion carbon black N550, 6 parts heat resistant agent, 2.5 parts vulcanizing agent, 3 parts vulcanization aid, 2 parts processing aid, and 15 parts carbon nanotube-ethanol mixture. The fluororubber has a fluorine content of 69.5%, the heat resistant agent is zinc oxide, the vulcanizing agent is dicumyl peroxide, the vulcanization aid is triallyl isocyanurate, and the processing aids are WS280 and fluorowax, used in amounts of 1 part and 1 part respectively. The carbon nanotube-ethanol mixture is prepared by uniformly mixing anhydrous ethanol and multi-walled carbon nanotubes at a mass ratio of 400:1.

[0020] The preparation method of the fluororubber material in this embodiment includes the following steps: Step 1: Add the weighed pyrolysis carbon black N990 and fast extrusion carbon black N550 to the weighed fluororubber raw rubber, and pass it through a two-roll mill with a roll gap of 0.8 mm and a roll temperature of 65℃ 5 times to obtain the masterbatch. Step 2: Add the carbon nanotubes to the anhydrous ethanol weighed in proportion in three portions, stirring while adding. After the addition is complete, stir for 50 minutes to obtain a carbon nanotube-ethanol mixture. Step 3: Place the masterbatch obtained in Step 1 on a two-roll mill, and evenly brush the weighed carbon nanotube-ethanol mixture from Step 2 onto the surface of the masterbatch. Brush once every 3 minutes until the carbon nanotube-ethanol mixture is completely brushed. Pass through the mill 18 times. The roller gap is 0.8 mm and the roller temperature is 75°C during the thin pass. Step 4: The masterbatch obtained in Step 3 is processed into a thin sheet with a thickness of 1.2 mm, and the sheet is dried in a constant temperature oven at 80°C for 4 hours. Step 5: Mix the dried film obtained in Step 4 with the heat resistant agent and processing aid in proportion on an open mill, and pass it through the mill 6 times. The roller gap during the thin pass is 0.8 mm and the roller temperature is 65℃. Step 6: Mix the masterbatch obtained in Step 5 with the vulcanizing agent and vulcanizing aid in proportion on a two-roll mill, then pass it through the two-roll mill with a roll gap of 0.8 mm and a roll temperature of 65°C 6 times to remove air and sheet it to obtain the compound.

[0021] Step 7: The mixture described in Step 6 is molded and vulcanized at 175°C for 15 minutes, and then vulcanized at a constant temperature in a 230°C oven for 10 hours to obtain fluororubber material.

[0022] Example 3 This embodiment provides a fluororubber material, the raw materials of which, by mass parts, include: 100 parts fluororubber, 25 parts thermally decomposed carbon black N990, 15 parts fast-extrusion carbon black N550, 4 parts heat resistant agent, 3 parts vulcanizing agent, 2 parts vulcanizing aid, 1.5 parts processing aid, and 50 parts carbon nanotube-ethanol mixture. The fluororubber has a fluorine content of 70%, the heat resistant agent is magnesium oxide, the vulcanizing agent is di-tert-butylperoxyisopropylbenzene, the vulcanizing aid is triallyl isocyanurate, and the processing aid is palm wax; the carbon nanotube-ethanol mixture is prepared by uniformly mixing anhydrous ethanol and multi-walled carbon nanotubes at a mass ratio of 600:1.5.

[0023] The preparation method of the fluororubber material in this embodiment includes the following steps: Step 1: Add the weighed pyrolysis carbon black N990 and fast extrusion carbon black N550 to the weighed fluororubber raw rubber, and pass it through a two-roll mill with a roll gap of 1 mm and a roll temperature of 70℃ 10 times to obtain the masterbatch. Step 2: Add the carbon nanotubes to the anhydrous ethanol weighed in proportion in three portions, stirring while adding. After the addition is complete, stir for 60 minutes to obtain a carbon nanotube-ethanol mixture. Step 3: Place the masterbatch obtained in Step 1 on a two-roll mill, and evenly brush the weighed carbon nanotube-ethanol mixture from Step 2 onto the surface of the masterbatch. Brush once every 3 minutes until the carbon nanotube-ethanol mixture is completely brushed. Pass through the mill 20 times. The roller gap is 1 mm and the roller temperature is 80°C during the thin pass. Step 4: The masterbatch obtained in Step 3 is processed into a thin sheet with a thickness of 1.5 mm, and the sheet is dried in a constant temperature oven at 75°C for 6 hours. Step 5: Mix the dried film obtained in Step 4 with the heat resistant agent and processing aid in proportion on a two-roll mill, and pass it through the mill 8 times. The roller gap during the thin pass is 1 mm and the roller temperature is 80℃. Step 6: Mix the masterbatch obtained in Step 5 with vulcanizing agent and vulcanizing aid in proportion on a two-roll mill, then pass it through a two-roll mill with a roll gap of 1 mm and a roll temperature of 60°C 8 times to remove air and sheet it to obtain the compound.

[0024] Step 7: The mixture described in Step 6 is molded and vulcanized at 180°C for 10 minutes, and then vulcanized at a constant temperature of 230°C in a constant temperature oven for 10 hours to obtain fluororubber material.

[0025] Example 4 This embodiment provides a fluororubber material. The raw materials, by mass parts, include: 100 parts perfluoroether rubber, 30 parts thermally decomposed carbon black N990, 15 parts rapid extrusion carbon black N550, 3 parts heat resistant agent, 1.5 parts vulcanizing agent, 4 parts vulcanizing aid, 1 part processing aid, and 10 parts carbon nanotube-ethanol mixture. The perfluoroether rubber has a fluorine content ≥72%, the heat resistant agent is zinc oxide, the vulcanizing agent is 2,5-dimethyl-2,5-di-tert-butylperoxyethane, the vulcanizing aid is triallyl isocyanurate, and the processing aid is HT-290. The carbon nanotube-ethanol mixture is prepared by uniformly mixing anhydrous ethanol and multi-walled carbon nanotubes at a mass ratio of 300:1.

[0026] The preparation method of the fluororubber material in this embodiment includes the following steps: Step 1: Add the weighed pyrolysis carbon black N990 and fast extrusion carbon black N550 to the weighed perfluoroether raw rubber, and pass it through a two-roll mill with a roll gap of 0.7 mm and a roll temperature of 80°C 8 times to obtain the masterbatch. Step 2: Add the carbon nanotubes to the anhydrous ethanol weighed in proportion in three portions, stirring while adding. After adding all the carbon nanotubes, stir for 30 minutes to obtain a carbon nanotube-ethanol mixture. Step 3: Place the masterbatch obtained in Step 1 on a two-roll mill, and evenly brush the weighed carbon nanotube-ethanol mixture from Step 2 onto the surface of the masterbatch. Brush once every 2.5 minutes until the carbon nanotube-ethanol mixture is completely brushed. Pass through the mill 18 times. The roller gap is 0.7 mm and the roller temperature is 60°C during the thin pass. Step 4: The masterbatch obtained in Step 3 is processed into a thin sheet with a thickness of 1 mm, and the sheet is dried in a constant temperature oven at 70°C for 4 hours. Step 5: Mix the dried film obtained in Step 4 with the heat resistant agent and processing aid in proportion on an open mill, and pass it through the mill 5 times. The roller gap during the thin pass is 0.7 mm and the roller temperature is 70℃. Step 6: Mix the masterbatch obtained in Step 5 with the vulcanizing agent and vulcanizing aid in proportion on a two-roll mill, then pass it through the mill 5 times at a roll gap of 0.7 mm and a roll temperature of 80°C to remove air and sheet the mixture to obtain the compound.

[0027] Step 7: The mixture described in Step 6 is molded and vulcanized at 170°C for 20 min, and then vulcanized at a constant temperature in a constant temperature oven at 230°C for 10 hours to obtain fluororubber material.

[0028] The high-temperature tensile strength and compression set properties of the fluororubber materials prepared in Examples 1 to 4 of this invention were tested, and the test results are shown in the table below.

[0029] This invention utilizes four core mechanisms—the intrinsic properties of the matrix material, the synergistic reinforcement of the filler, the optimization of the vulcanization crosslinking network, and the precise modification of carbon nanotubes—to synergistically produce a rubber material with excellent resistance to high temperature, high pressure, low compression set, and high strength retention. This material is suitable for use as a fluororubber sealing ring in ultra-deep well logging equipment, adaptable to the harsh operating conditions of 200°C and 180MPa in ultra-deep wells ranging from 8000 to 10000 meters.

Claims

1. A fluororubber material, characterized in that, The raw materials, by weight, include: 100 parts of fluororubber raw rubber, 25-35 parts of pyrolysis carbon black N990, 5-15 parts of fast extrusion carbon black N550, 3-6 parts of heat resistant agent, 1.5-3 parts of vulcanizing agent, 2.5-4 parts of vulcanizing aid triallyl isocyanurate, 1-2 parts of processing aid, and 10-50 parts of carbon nanotube-ethanol mixture.

2. The fluororubber material according to claim 1, characterized in that, The fluororubber raw rubber is fluororubber raw rubber or perfluoroether raw rubber with a fluorine content of ≥69%.

3. The fluororubber material according to claim 1, characterized in that, The heat-resistant agent includes any one of calcium oxide, magnesium oxide, and zinc oxide.

4. The fluororubber material according to claim 1, characterized in that, The vulcanizing agent includes any one of 2,5-dimethyl-2,5-di-tert-butylperoxyethane, dicumyl peroxide, and bis-tert-butylperoxyisopropylbenzene.

5. The fluororubber material according to claim 1, characterized in that, The processing aids include one or more of WS280, carnauba wax, HT-290, and fluorinated wax.

6. The fluororubber material according to claim 1, characterized in that, The carbon nanotube-ethanol mixture is prepared by uniformly mixing anhydrous ethanol and multi-walled carbon nanotubes at a mass ratio of (300~600):(1~1.5).

7. A method for preparing a fluororubber material according to any one of claims 1 to 6, characterized in that, Includes the following steps: Step 1: Add the weighed pyrolysis carbon black N990 and fast extrusion carbon black N550 to the weighed fluororubber raw rubber, and pass it through a two-roll mill 5 to 10 times to obtain the masterbatch. Step 2: Add the carbon nanotubes to the weighed anhydrous ethanol in three portions according to the proportion, stirring while adding. After adding all the carbon nanotubes, stir for 30-60 minutes to obtain a carbon nanotube-ethanol mixture. Step 3: Place the masterbatch obtained in Step 1 on a two-roll mill and pass it through the mill. Apply the weighed carbon nanotube-ethanol mixture from Step 2 evenly to the surface of the masterbatch. Apply the mixture every 2 to 3 minutes until the carbon nanotube-ethanol mixture is completely applied. Pass through the mill 15 to 20 times. Step 4: The masterbatch obtained in Step 3 is processed into thin rubber sheets with a thickness of 1~1.5mm, and the thin rubber sheets are dried in a constant temperature oven. Step 5: Mix the dried film obtained in Step 4 with the heat resistant agent and processing aid in proportion on a two-roll mill, and pass through the mill 5 to 8 times. Step 6: Mix the masterbatch obtained in Step 5 with vulcanizing agent and vulcanizing aid in proportion on a two-roll mill, pass through a thin mill 5 to 8 times, degas and sheet to obtain the compound. Step 7: The mixture described in Step 6 is molded and vulcanized at 170~180℃ for 10~20 minutes, and then vulcanized at a constant temperature in a constant temperature oven at 230℃ for 10 hours to obtain fluororubber material.

8. The method for preparing fluororubber material according to claim 7, characterized in that, In steps 1, 3, 5, and 6, the roller gap during thin-pass operation is 0.7~1mm, and the roller temperature is 60~80℃.

9. The method for preparing fluororubber material according to claim 7, characterized in that, The drying temperature in step 4 is 70~80℃, and the drying time is 4~6 h.

10. The application of any one of the fluororubber materials according to claims 1 to 6 in fluororubber sealing rings for ultra-deep well logging equipment.

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