Low-temperature-resistant oil-resistant rubber sealing ring material and preparation method thereof

Abstract

The invention relates to the technical field of oil field chemicals, in particular to a low-temperature-resistant oil-resistant rubber sealing ring material and a preparation method thereof. The raw materials of the material comprise a raw rubber system, diatomite and high-purity multilayer graphene oxide, the raw rubber system comprises nitrile rubber, butadiene rubber and ethylene propylene diene monomer. Nitrile rubber and butadiene rubber enable the material to have good oil-resistant and low-temperature-resistant characteristics, and ethylene propylene diene monomer enable the material to have good anti-aging performance; the diatomite and the high-purity multilayer graphene oxide can effectively improve the strength and the volume stability of the material; the sealing ring has low temperature resistance and oil resistance, can be used in a low-temperature environment of-35 DEG C, has the Shore A hardness of 90 degrees, the tensile strength of more than or equal to 18MPa and the compression set of less than or equal to 35%, and can be used in the low-temperature environment for a slurry pump during site construction.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield chemicals, and in particular to a low-temperature and oil-resistant rubber sealing ring material and a preparation method thereof. Background Art

[0002] Rubber is a highly elastic polymer material with excellent elasticity at room temperature. It can produce large deformation under very small external force and return to its original shape after the external force is removed. When rubber is placed in various pump body valve covers and valve connections, it can play an excellent sealing role and is often made into sealing rings. Especially for oilfield mud pumps, rubber sealing rings are one of the important components that affect their functions.

[0003] Conventional sealing rings are required to have high tensile properties, aging resistance, low compression permanent deformation and low compression stress relaxation, so they are generally only made of natural rubber and EPDM rubber, but they are not oil-resistant and low-temperature resistant. In some special fields with extremely high requirements for oil resistance, such as mud pumps and oil pipelines in oil fields, inflammable and explosive gases and oils can cause life and property safety problems if not handled with care. At the same time, the winter in Xinjiang and Northeast my country is very cold, and rubber is required to have excellent low-temperature resistance to ensure that the rubber still has a sealing effect in a low-temperature environment. Therefore, rubber sealing rings that are resistant to aging, deformation, oil and low-temperature resistance have received widespread attention.

[0004] Oil resistance and low temperature resistance are two contradictory properties. Improving one means sacrificing the other. In nitrile rubber, the higher the acrylonitrile content, the better the oil resistance, but the worse the low temperature resistance. Balancing oil resistance and low temperature resistance is still a major problem. If the oil resistance and low temperature resistance of the material are difficult to balance, the sealing ring prepared by it will be difficult to meet the requirements of low temperature environment, which will have a great impact on the operation of oilfield mud pumps. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a low-temperature and oil-resistant rubber sealing ring material and a preparation method to solve the problems that the materials in the prior art are difficult to have both oil resistance and low-temperature resistance, low strength, poor tensile properties, and poor sealing.

[0006] The technical solution of the present invention to solve the above technical problems is as follows:

[0007] The invention provides a low-temperature and oil-resistant rubber sealing ring material. The raw materials of the material include a raw rubber system, diatomaceous earth and high-purity multilayer graphene oxide; the raw rubber system includes nitrile rubber, butadiene rubber and ethylene propylene diene rubber.

[0008] Based on the above technical solution, the present invention can also be improved as follows.

[0009] Furthermore, the high-purity multilayer graphene oxide is nanographene, the fixed carbon content is greater than or equal to 99.9%, and the particle size of the sieve undersize is 4μm-0.335nm.

[0010] Furthermore, the median particle size of the diatomite is 6-10 microns and the specific surface area is 25-35 m 2 / g.

[0011] Furthermore, the mass ratio of the high-purity multilayer graphene oxide to the diatomaceous earth is 1:1-3.

[0012] Furthermore, in the raw rubber system, the mass ratio of the nitrile rubber, the butadiene rubber and the ethylene propylene diene monomer rubber is 6-7:1-2:1-3.

[0013] Furthermore, it also includes a compatibilizer, and the compatibilizer is maleic anhydride grafted ethylene propylene diene monomer rubber.

[0014] The present invention also provides a method for preparing the low-temperature and oil-resistant rubber sealing ring material as described above, comprising the following steps:

[0015] S1, uniformly spraying an ethanol solution of a silane coupling agent KH570 on the diatomite and the high-purity multilayer graphene oxide, drying, and mixing with calcium stearate to prepare material A;

[0016] S2, preparing material B containing a compatibilizer;

[0017] S3, mixing polyethylene and polypropylene wax with the material A, nano titanium dioxide and nano calcium carbonate and granulating them to obtain material C;

[0018] S4, mixing the nitrile rubber, the butadiene rubber and the ethylene propylene diene rubber to obtain the raw rubber system, and then mixing the raw rubber system with the material B and the material C, and subjecting the mixture to a mixing treatment and cooling to obtain a mixed rubber material D;

[0019] S5. The mixed rubber material D is mixed with an active stabilizer, an antioxidant, a dispersant, an anti-aging agent, an accelerator, a vulcanizer, and a cold-resistant plasticizer to obtain a mixed material; and the mixed material is prepared into the low-temperature resistant rubber sealing ring material.

[0020] Furthermore, in the step S1, the mass ratio of the high-purity multilayer graphene oxide, the diatomaceous earth, the silane coupling agent KH570, and the calcium stearate is 1:1-3:0.01-0.05:0.03-0.2.

[0021] Furthermore, in step S3, the amounts of the components used are, by weight, 70-80 parts of polyethylene, 10-20 parts of polypropylene wax, 3-10 parts of material A, 1-3 parts of nano titanium dioxide, and 1-5 parts of nano calcium carbonate.

[0022] Furthermore, in step S4, the temperature of the banburying treatment is 110-140° C., and the time of the banburying treatment is 10-30 min.

[0023] Furthermore, in step S4, the mass proportions of the components are: 60-70 parts of the nitrile rubber, 10-20 parts of the butadiene rubber, 10-30 parts of the EPDM rubber, 3-7 parts of the material B, and 1-3 parts of the material C.

[0024] Further, in step S5, the active stabilizer is zinc oxide and stearic acid, the antioxidant is antioxidant 168, the dispersant is a saturated fatty acid dispersant, the antioxidant is N-(4-anilinophenyl)acetamide NLB, the accelerator is dipentamethylenethiuram tetrasulfide DPTT, and the cold-resistant plasticizer is one or more of dioctyl adipate DOA, diisodecyl adipate D IDA, dioctyl phthalate DOP, and dibutyl diglyceride TP95.

[0025] Furthermore, in step S5, the vulcanizing agent is a composite vulcanization system, and the composite vulcanization system includes sulfur, p-benzoquinone dioxime, isopropylbenzene peroxide, and phenolic resin, and the mass ratio of each component is 1:0.5:0.5:0.3.

[0026] Furthermore, in step S5, the mass proportions of each component are: 100 parts of the mixed rubber material D, 2-5 parts of the active stabilizer, 1-3 parts of the antioxidant, 1-3 parts of the dispersant, 2-5 parts of the antioxidant, 1-3 parts of the accelerator, 1-3 parts of the vulcanizer, and 10-40 parts of the cold-resistant plasticizer.

[0027] The invention also provides a low-temperature resistant rubber sealing ring for an oilfield mud pump, which is prepared by adopting the above-mentioned material.

[0028] The beneficial effects of the present invention are:

[0029] (1) The low-temperature and oil-resistant rubber sealing ring material of the present invention comprises a nitrile rubber (NBR), butadiene rubber (BR) and ethylene propylene diene rubber (EPDM) as a raw rubber system, wherein the nitrile rubber and butadiene rubber enable the material to have good oil and low-temperature resistance, and the ethylene propylene diene rubber enables the material to have good anti-aging performance;

[0030] (2) The low-temperature and oil-resistant rubber sealing ring material of the present invention, diatomaceous earth and high-purity multilayer graphene oxide can effectively improve the strength and volume stability of the material;

[0031] (3) The low temperature and oil resistant rubber sealing ring material of the present invention is further added with a compatibilizer (EPDM-g-MAH), which can make the nitrile rubber and the EPDM rubber well compatible;

[0032] (4) The method for preparing the low-temperature and oil-resistant rubber sealing ring material of the present invention uses silane coupling agent KH570 and calcium stearate to modify diatomaceous earth and high-purity multilayer graphene oxide, thereby increasing the compatibility with polyethylene;

[0033] (5) The method for preparing the low-temperature and oil-resistant rubber sealing ring material of the present invention uses polyethylene to increase the strength of the rubber matrix and reduce the preparation cost, and uses polypropylene wax to evenly disperse nano-titanium dioxide and nano-calcium carbonate in the matrix to make the materials more compatible; nano-titanium dioxide can improve the thermal stability and weather resistance of the rubber material;

[0034] (6) The composite vulcanizing agent used in the method for preparing the low-temperature and oil-resistant rubber sealing ring material of the present invention can improve the wear resistance of the material to a comprehensive extent;

[0035] (7) The low-temperature resistant rubber seal ring for the oilfield mud pump of the present invention has both low-temperature resistance and oil resistance, and can be used in a low-temperature environment of -35°C. The Shore A hardness of the seal ring can reach 90°, the tensile strength is ≥18MPa, and the compression permanent deformation is ≤35%, which can meet the use of the mud pump in a low-temperature environment during on-site construction. DETAILED DESCRIPTION

[0036] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0037] The low-temperature and oil-resistant rubber sealing ring material of the present invention comprises raw materials including a raw rubber system, diatomaceous earth and high-purity multilayer graphene oxide; the raw rubber system comprises nitrile rubber, butadiene rubber and ethylene propylene diene rubber.

[0038] The low temperature and oil resistant rubber sealing ring material of the present invention, by adding diatomite and high-purity multilayer graphene oxide, can effectively improve the strength and volume stability of the material; butadiene rubber (BR) has excellent low temperature resistance, and the glass transition temperature of cis-butadiene rubber is -105°C, which has very good cold resistance, therefore, the nitrile rubber and cis-butadiene rubber in the raw rubber system realize the oil resistance and low temperature resistance of the material; EPDM rubber has better anti-aging performance and can adapt to more severe environmental conditions, therefore, the present invention also adds EPDM rubber, which can effectively improve the strength and weather resistance of the material. In addition, the raw rubber system of the present invention can also provide a high elastic modulus for the material, thereby ensuring that the obtained sealing ring has good sealing performance.

[0039] Preferably, the high-purity multilayer graphene oxide of the present invention is nanographene, with a fixed carbon content greater than or equal to 99.9% and a sieve undersize particle size of 4 μm-0.335 nm.

[0040] Preferably, the median particle size of the diatomaceous earth of the present invention is 6 to 10 microns, and the specific surface area is 25 to 35 m 2 / g.

[0041] Preferably, in the raw material of the present invention, the mass ratio of high-purity multilayer graphene oxide to the diatomaceous earth is 1:1-3.

[0042] Preferably, in the raw rubber system of the present invention, the mass ratio of nitrile rubber, butadiene rubber and ethylene propylene diene rubber is 6-7:1-2:1-3.

[0043] The low-temperature and oil-resistant rubber sealing ring material of the present invention further comprises a compatibilizer in the raw materials, and the compatibilizer is maleic anhydride grafted ethylene propylene diene monomer rubber (EPDM-g-MAH); the compatibilizer (EPDM-g-MAH) can effectively increase the compatibility of nitrile rubber and ethylene propylene diene monomer rubber.

[0044] The preparation method of the low temperature and oil resistant rubber sealing ring material of the present invention comprises the following steps:

[0045] S1. Evenly spray an ethanol solution of silane coupling agent KH570 on diatomaceous earth and high-purity multilayer graphene oxide, dry them, and mix them with calcium stearate to prepare material A.

[0046] In the method of the present invention, nano-graphene and diatomaceous earth materials are modified, pre-treated with silane coupling agent KH570, and then coated with calcium stearate by dry method to increase the compatibility with polyethylene.

[0047] Preferably, the mass ratio of high-purity multilayer graphene oxide, diatomaceous earth, silane coupling agent KH570, and calcium stearate is 1:(1-3):(0.01-0.05):(0.03-0.2).

[0048] Preferably, the drying temperature of this step is 80° C. After the ingredients are premixed, they are poured into a grinder and ground at a speed of 25,000 r / min for 5 minutes. After being taken out and cooled, material A is obtained.

[0049] S2. Prepare material B containing a compatibilizer.

[0050] In this step, maleic anhydride (MAH) grafted ethylene propylene diene monomer (EPDM) compatibilizer (EPDM-g-MAH) is prepared by melt intercalation method in a torque rheometer. The specific preparation process is as follows:

[0051] After premixing EPDM, maleic anhydride MAH, benzoyl peroxide (BPO), etc., add them into the preheated torque rheometer in a certain order and a certain proportion, mix them at 180°C and 70r / min for 10 minutes, then extrude and granulate. The grafted product is vacuum dried at 70°C for 10 hours, and the unreacted MAH monomer on the surface of the product is sublimated and removed to obtain a compatibilizer, namely material B.

[0052] S3, mixing polyethylene and polypropylene wax with the material A, nano titanium dioxide and nano calcium carbonate and granulating them to obtain material C.

[0053] In this step, the added polyethylene can increase the strength of the rubber matrix, and the addition of nano calcium carbonate can further strengthen the material. The added polypropylene wax can activate nano calcium carbonate and nano titanium dioxide, so that both can be evenly dispersed in the matrix, thereby making the materials more compatible; nano titanium dioxide can improve the thermal stability and weather resistance of the rubber material.

[0054] Preferably, the amounts of the components used are, by weight, 70-80 parts of polyethylene, 10-20 parts of polypropylene wax, 3-10 parts of material A, 1-3 parts of nano titanium dioxide, and 1-5 parts of nano calcium carbonate.

[0055] Preferably, this step uses a torque rheometer for granulation.

[0056] S4. A raw rubber system is obtained by mixing nitrile rubber, butadiene rubber and ethylene propylene diene rubber, and then the raw rubber system is mixed with material B and material C, and subjected to internal mixing treatment and cooling to obtain a mixed rubber material D.

[0057] Preferably, the mass proportions of the components in this step are: 60-70 parts of nitrile rubber, 10-20 parts of butadiene rubber, 10-30 parts of EPDM rubber, 3-7 parts of material B, and 1-3 parts of material C.

[0058] Preferably, after the components are premixed in this step, the temperature of the banburying treatment is 110-140° C., and the time of the banburying treatment is 10-30 min.

[0059] S5. The mixed rubber material D is mixed with an active stabilizer, an antioxidant, a dispersant, an anti-aging agent, an accelerator, a vulcanizer, and a cold-resistant plasticizer to obtain a mixed material; and the mixed material is then prepared into a low-temperature resistant rubber sealing ring material.

[0060] Preferably, the vulcanizing agent is a composite vulcanization system, which includes sulfur, p-benzoquinone dioxime, isopropylbenzene peroxide, and phenolic resin, and the mass ratio of each component is 1:0.5:0.5:0.3.

[0061] Composite vulcanizing agents can effectively improve the wear resistance of materials to a comprehensive extent.

[0062] Preferably, the active stabilizer is zinc oxide and stearic acid, the antioxidant is antioxidant 168, the dispersant is a saturated fatty acid dispersant, the antioxidant is N-(4-anilinophenyl)acetamide NLB, the accelerator is dipentamethylenethiuram tetrasulfide DPTT, and the cold-resistant plasticizer is one or more of dioctyl adipate DOA, diisodecyl adipate D IDA, dioctyl phthalate DOP, and dibutyl diglycerol adipate TP95.

[0063] More preferably, the cold-resistant plasticizer is diisodecyl adipate D IDA.

[0064] Preferably, the components in this step are mixed according to the following mass parts: 100 parts of rubber compound material D, 2-5 parts of active stabilizer, 1-3 parts of antioxidant, 1-3 parts of dispersant, 2-5 parts of antioxidant, 1-3 parts of accelerator, 1-3 parts of vulcanizer, and 10-40 parts of cold-resistant plasticizer.

[0065] Further preferably, the active stabilizer is 4 parts, the antioxidant is 1 part, the dispersant is 1 part, the antioxidant is 2 parts, the accelerator is 2 parts, the vulcanizer is 2.3 parts, and the cold-resistant agent is 30 parts.

[0066] Preferably, the specific process of this step is to add the components into an open mill respectively for mixing and refining to obtain a mixed material; then place the mixed material in a mold for molding to obtain a low-temperature resistant rubber sealing ring material.

[0067] The low temperature resistant rubber seal ring for oilfield mud pump of the present invention is prepared by using the material of the present invention. The rubber seal ring can be used in a low temperature environment of -35°C, the seal ring Shore A hardness can reach 90°, the tensile strength is ≥18MPa, and the compression permanent deformation is ≤35%, which can meet the requirements of using the mud pump in a low temperature environment during on-site construction.

[0068] The present invention is illustrated below by means of specific examples.

[0069] In the following examples, the specific information of some substances is as follows: the melting point of polyethylene is 116°C, and the melt flow rate is 6.78g / 10min (under a load of 116°C / 6.78kg); nitrile rubber (NBR), a product of Japan Synthetic Rubber Company, JSR250S. Butadiene rubber (BR), a product of Shanghai Gaoqiao Petrochemical Company, brand 9000. Ethylene propylene diene monomer rubber (EPDM), a product of DuPont Company, USA, brand 4770. High-purity multilayer graphene oxide is nanographene with a fixed carbon content of 99.9% and a sieve particle size of 4μm-0.335nm. Diatomaceous earth is diatomaceous earth MN-23, with a median particle size of 8 microns and a specific surface area of ​​30m 2 / g.

[0070] Example 1

[0071] This embodiment adopts the method of the present invention to prepare a low-temperature and oil-resistant rubber sealing ring material, and the specific preparation process is as follows:

[0072] (1) 50 ml of 95% ethanol by volume and 50 g of silane coupling agent KH570 were mixed evenly, and then sprayed on the surface of 1 kg of nanographene carbon and 2 kg of diatomaceous earth respectively. After drying at 80°C, 100 g of calcium stearate was evenly added to 1 kg of nanographene carbon and 2 kg of diatomaceous earth respectively, and after premixing, poured into a pulverizer and ground at a speed of 25000 r / min for 5 min, and the sample was taken out and the material A was cooled.

[0073] (2) After premixing EPDM, maleic anhydride MAH, benzoyl peroxide (BPO), etc., add them into the preheated torque rheometer in a certain order and a certain proportion, mix them at 180°C and 70r / min for 10 minutes, and then extrude and granulate. The grafted product is vacuum dried at 70°C for 10 hours to sublimely remove the unreacted MAH monomer on the surface of the product. The dried material B is set aside.

[0074] (3) 70 g of polyethylene, 10 g of polypropylene wax, 20 g of material A, 1 g of nano-titanium dioxide, and 2 g of nano-calcium carbonate were premixed and added to a torque rheometer for granulation to obtain material C for standby use.

[0075] (4) Take 60g of nitrile rubber (NBR), 15g of butadiene rubber (BR), and 15g of ethylene propylene diene rubber (EPDM) and use them as the raw rubber system, add 5g of material B and 5g of material C, and then add them into an internal mixer, mix them at 125°C for 10min, and then cool them to room temperature to obtain a mixed rubber material D.

[0076] (5) 100 g of mixed rubber material D, active stabilizer (2 g of zinc oxide and 2 g of stearic acid), 1 g of antioxidant 168, 1 g of dispersant saturated fatty acid, 2 g of antioxidant N-(4-anilinophenyl)acetamide, 2 g of accelerator dipentamethylenethiuram tetrasulfide, composite vulcanization system (1 g of sulfur, 0.5 g of p-benzoquinone dioxime, 0.5 g of isopropyl peroxide, 0.3 g of phenolic resin), and 30 g of cold-resistant plasticizer diisodecyl adipate D IDA were added into an open mill for mixing and mixing to obtain a mixed material; the mixed material was placed in a mold for molding to obtain a low-temperature resistant rubber sealing ring material.

[0077] Example 2

[0078] This embodiment adopts the method of the present invention to prepare a low-temperature and oil-resistant rubber sealing ring material, and the specific preparation process is as follows:

[0079] (1) After 50 ml of 95% by volume ethanol and 50 g of silane coupling agent KH570 were mixed evenly, the mixture was sprayed on the surface of 1 kg of nano-graphene carbon and 3 kg of diatomaceous earth respectively. After drying at 80°C, 100 g of calcium stearate was evenly added to 1 kg of nano-graphene carbon and 2 kg of diatomaceous earth respectively. After premixing, the mixture was poured into a pulverizer and ground at a speed of 25,000 r / min for 5 min. The sample was taken out and the material A was cooled.

[0080] (2) After premixing EPDM, maleic anhydride MAH, benzoyl peroxide (BPO), etc., add them into the preheated torque rheometer in a certain order and a certain proportion, mix them at 180°C and 70r / min for 10 minutes, and then extrude and granulate. The grafted product is vacuum dried at 70°C for 10 hours to sublimely remove the unreacted MAH monomer on the surface of the product. The dried material B is set aside.

[0081] (3) 70 g of polyethylene, 10 g of polypropylene wax, 20 g of material A, 1 g of nano-titanium dioxide, and 2 g of nano-calcium carbonate were premixed and added to a torque rheometer for granulation to obtain material C for standby use.

[0082] (4) Take 60g of nitrile rubber (NBR), 15g of butadiene rubber (BR), and 15g of ethylene propylene diene rubber (EPDM) and use them as the raw rubber system, add 5g of material B and 5g of material C, and then add them into an internal mixer, mix them at 125°C for 10min, and then cool them to room temperature to obtain a mixed rubber material D.

[0083] (5) 100 g of mixed rubber material D, 2 g of active stabilizer zinc oxide and 2 g of stearic acid, 1 g of antioxidant 168, 1 g of dispersant saturated fatty acid, 2 g of antioxidant N-(4-anilinophenyl)acetamide, 2 g of accelerator dipentamethylenethiuram tetrasulfide, a composite vulcanization system (1 g of sulfur, 0.5 g of p-benzoquinone dioxime, 0.5 g of isopropyl peroxide, 0.3 g of phenolic resin), and 30 g of cold-resistant plasticizer diisodecyl adipate D IDA were added into an open mill for mixing and mixing to obtain a mixed material; the mixed material was placed in a mold for molding to obtain a low-temperature resistant rubber sealing ring material.

[0084] Example 3

[0085] This embodiment adopts the method of the present invention to prepare a low-temperature and oil-resistant rubber sealing ring material, and the specific preparation process is as follows:

[0086] (1) After 50 ml of 95% by volume ethanol and 50 g of silane coupling agent KH570 were mixed evenly, the mixture was sprayed on the surface of 1 kg of nano-graphene carbon and 2 kg of diatomaceous earth respectively. After drying at 80°C, 100 g of calcium stearate was evenly added to 1 kg of nano-graphene carbon and 2 kg of diatomaceous earth respectively. After premixing, the mixture was poured into a pulverizer and ground at a speed of 25,000 r / min for 5 min. The sample was taken out and the material A was cooled.

[0087] (2) After premixing EPDM, maleic anhydride MAH, benzoyl peroxide (BPO), etc., add them into the preheated torque rheometer in a certain order and a certain proportion, mix them at 180°C and 70r / min for 10 minutes, and then extrude and granulate. The grafted product is vacuum dried at 70°C for 10 hours to sublimely remove the unreacted MAH monomer on the surface of the product. The dried material B is set aside.

[0088] (3) 50 g of polyethylene, 10 g of polypropylene wax, 40 g of material A, 1 g of nano-titanium dioxide, and 2 g of nano-calcium carbonate were premixed and added to a torque rheometer for granulation to obtain material C for standby use.

[0089] (4) Take 60g of nitrile rubber (NBR), 15g of butadiene rubber (BR), and 15g of ethylene propylene diene rubber (EPDM) and use them as the raw rubber system, add 5g of material B and 5g of material C, and then add them into an internal mixer, mix them at 125°C for 10min, and then cool them to room temperature to obtain a mixed rubber material D.

[0090] (5) 100 g of mixed rubber material D, 2 g of active stabilizer zinc oxide and 2 g of stearic acid, 1 g of antioxidant 168, 1 g of dispersant saturated fatty acid, 2 g of antioxidant N-(4-anilinophenyl)acetamide, 2 g of accelerator dipentamethylenethiuram tetrasulfide, a composite vulcanization system (1 g of sulfur, 0.5 g of p-benzoquinone dioxime, 0.5 g of isopropyl peroxide, 0.3 g of phenolic resin), and 10 g of cold-resistant plasticizer diisodecyl adipate D IDA were added into an open mill for mixing and mixing to obtain a mixed material; the mixed material was placed in a mold for molding to obtain a low-temperature resistant rubber sealing ring material.

[0091] Example 4

[0092] This embodiment adopts the method of the present invention to prepare a low-temperature and oil-resistant rubber sealing ring material, and the specific preparation process is as follows:

[0093] (1) After 50 ml of 95% by volume ethanol and 50 g of silane coupling agent KH570 were mixed evenly, the mixture was sprayed on the surface of 1 kg of nano-graphene carbon and 2 kg of diatomaceous earth respectively. After drying at 80°C, 100 g of calcium stearate was evenly added to 1 kg of nano-graphene carbon and 2 kg of diatomaceous earth respectively. After premixing, the mixture was poured into a pulverizer and ground at a speed of 25,000 r / min for 5 min. The sample was taken out and the material A was cooled.

[0094] (2) After premixing EPDM, maleic anhydride MAH, benzoyl peroxide (BPO), etc., add them into the preheated torque rheometer in a certain order and a certain proportion, mix them at 180°C and 70r / min for 10 minutes, and then extrude and granulate. The grafted product is vacuum dried at 70°C for 10 hours to sublimely remove the unreacted MAH monomer on the surface of the product. The dried material B is set aside.

[0095] (3) 60 g of polyethylene, 10 g of polypropylene wax, 20 g of material A, 1 g of nano-titanium dioxide, and 2 g of nano-calcium carbonate were premixed and added to a torque rheometer for granulation to obtain material C for standby use.

[0096] (4) Take 60g of nitrile rubber (NBR), 15g of butadiene rubber (BR), and 15g of ethylene propylene diene rubber (EPDM) and use them as the raw rubber system, add 5g of material B and 5g of material C, and then add them into an internal mixer, mix them at 125°C for 10min, and then cool them to room temperature to obtain a mixed rubber material D.

[0097] (5) 100 g of mixed rubber material D, 2 g of active stabilizer zinc oxide and 2 g of stearic acid, 1 g of antioxidant 168, 1 g of dispersant saturated fatty acid, 2 g of antioxidant N-(4-anilinophenyl)acetamide, 2 g of accelerator dipentamethylenethiuram tetrasulfide, a composite vulcanization system (1 g of sulfur, 0.5 g of p-benzoquinone dioxime, 1 g of isopropyl peroxide, 0.5 g of phenolic resin), and 40 g of cold-resistant plasticizer diisodecyl adipate D IDA were added to an open mill for mixing and mixing to obtain a mixed material; the mixed material was placed in a mold for molding to obtain a low-temperature resistant rubber sealing ring material.

[0098] Comparative Example 1

[0099] The difference between this comparative example and Example 1 is that in step (1), the amount of nanographene is 3 kg and diatomaceous earth is not added. The other conditions are the same as those in Example 1.

[0100] Comparative Example 2

[0101] The difference between this comparative example and Example 1 is that in step (1), 3 kg of diatomaceous earth is used and no nanographene is added. Other conditions are the same as those in Example 1.

[0102] Comparative Example 3

[0103] The difference between this comparative example and Example 1 is that in step (4), the rubber compatibilizer material B is not used to treat the raw rubber system. The other conditions are the same as those in Example 1.

[0104] Comparative Example 4

[0105] The difference between this comparative example and Example 1 is that in step (4), the amount of reinforcing masterbatch material C added is 10 g. The other conditions are the same as those in Example 1.

[0106] Comparative Example 5

[0107] The difference between this comparative example and Example 1 is that the composite vulcanization system is replaced by sulfur, and the other conditions are the same as those in Example 1.

[0108] The rubber sealing ring materials prepared in the above-mentioned Examples 1-4 and Comparative Examples 1-5 were subjected to performance tests, and the test methods and test results are as follows:

[0109] (1) Shore A hardness: Tested in accordance with GB / T531-2008.

[0110] (2) Tensile strength: tested according to GB / T528-2009 method.

[0111] (3) Hot air aging performance (100℃×100h), tested in accordance with GB / T3512-2018 method.

[0112] (4) Compression set % (100°C × 22h × 30% compression), tested in accordance with GB / T1683-2018 method.

[0113] (5) Low temperature brittleness: The samples were tested for low temperature brittleness in accordance with the national recommended standard GB / T°1682-2014 Single Specimen Method for Determination of Low Temperature Brittleness of Vulcanized Rubber. The test temperature was -35°C.

[0114] (6) Oil resistance: Resistance to No. 1 standard oil, 100°C, 72h, volume change rate %, oil resistance test in accordance with GB / T1690-2010 Test method for liquid resistance of vulcanized rubber or thermoplastic rubber.

[0115] The above test results are shown in Table 1.

[0116] Table 1 Test results of various embodiments and comparative examples

[0117]

[0118] It can be seen from the test results in Table 1 that the rubber sealing ring material provided by the present invention not only has good mechanical properties, but also has excellent heat aging resistance, good volume stability, resistance to low temperature environments, and oil resistance.

[0119] It can be seen from Example 1, Example 2, Example 3 and Comparative Example 3 that with the increase in the amount of nanographene and diatomaceous earth added, the hardness, tensile strength and volume stability of the material are effectively improved, but when the amount added is too much, the above properties decrease. On the one hand, excessive addition of nanographene and diatomaceous earth will affect their dispersibility in the rubber material. If these additives are not fully dispersed, they may aggregate together, which will reduce the overall performance of the rubber material. Excessive addition may increase the difficulty of dispersing these substances in the rubber material, thereby reducing the dispersion effect; on the other hand, the crosslinking density is a key factor in the mechanical properties of the rubber material. Nanographene and diatomaceous earth may change the crosslinking density of the rubber material, thereby affecting its mechanical properties. If the additives are excessive, it may interfere with the normal crosslinking process, resulting in a decrease in the crosslinking density, thereby affecting the mechanical properties of the rubber material.

[0120] From the test results of Comparative Example 1, Comparative Example 2 and Example 1, it can be seen that although the hardness and tensile strength of the material are improved to a certain extent by adding nanographene alone to the rubber material, the volume stability of the material is deteriorated, and the low-temperature brittleness is not significantly improved. This is mainly because although nanographene has high strength, it cannot improve the low-temperature rebound performance of the material well. On the contrary, if only diatomaceous earth material is added to the material, the improvement of the tensile strength and hardness of the material is not obvious.

[0121] From the comparison between the test results of Comparative Example 3 and Example 1, it can be seen that the use of rubber compatibilizer material B to treat the raw rubber system is better than that of the material not used. This is mainly because the non-polar end of the rubber compatibilizer material B (EPDM-g-MAH) is first combined with EPDM and NB and coated on the surface of EPDM and NB, and the polar group at the other end is bonded to NBR, so that the NBR fragments can adhere to the EPDM and NB particles at the initial stage of mixing, and then they are quickly subdivided into very small particles together by shearing, thereby improving the size of NBR particles in the rubber structure and improving the physical and mechanical properties of the combined rubber.

[0122] It can be seen from the comparison of the test results of Comparative Example 5 and Example 1 that the hardness and tensile strength of the material using the rubber composite vulcanization system are better than those of the material using sulfur rubber. This is mainly because the rubber composite vulcanization system increases the crosslinking density during the vulcanization process, improves the hardness and heat resistance of the material, and the oil resistance and solvent resistance of the vulcanized rubber.

[0123] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A low temperature and oil resistant rubber sealing ring material, characterized in that: The raw materials of the material include a raw rubber system, diatomaceous earth and high-purity multilayer graphene oxide; the raw rubber system includes nitrile rubber, butadiene rubber and ethylene propylene diene rubber.

2. The low temperature and oil resistant rubber sealing ring material according to claim 1, characterized in that: The high-purity multilayer graphene oxide is nanographene, the fixed carbon content of the nanographene is greater than or equal to 99.9%, and the particle size of the sieve material is 4μm-0.335nm.

3. The low temperature and oil resistant rubber sealing ring material according to claim 1, characterized in that: The median particle size of the diatomaceous earth is 6-10 microns, and the specific surface area is 25-35m 2 / g.

4. A low temperature and oil resistant rubber sealing ring material according to any one of claims 1 to 3, characterized in that: The mass ratio of the high-purity multilayer graphene oxide to the diatomaceous earth is 1:1-3.

5. A low temperature and oil resistant rubber sealing ring material according to any one of claims 1 to 3, characterized in that: In the raw rubber system, the mass ratio of the nitrile rubber, the butadiene rubber and the ethylene propylene diene monomer rubber is 6-7:1-2:1-3.

6. A low temperature and oil resistant rubber sealing ring material according to any one of claims 1 to 3, characterized in that: The invention also comprises a compatibilizer, wherein the compatibilizer is maleic anhydride grafted ethylene propylene diene monomer rubber.

7. A method for preparing the low temperature and oil resistant rubber sealing ring material according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1, uniformly spraying an ethanol solution of a silane coupling agent KH570 on the diatomite and the high-purity multilayer graphene oxide, drying, and mixing with calcium stearate to prepare material A; S2, preparing material B containing a compatibilizer; S3, mixing polyethylene and polypropylene wax with the material A, nano titanium dioxide and nano calcium carbonate and granulating them to obtain material C; S4, mixing the nitrile rubber, the butadiene rubber and the ethylene propylene diene rubber to obtain the raw rubber system, and then mixing the raw rubber system with the material B and the material C, and subjecting the mixture to a mixing treatment and cooling to obtain a mixed rubber material D; S5. The mixed rubber material D is mixed with an active stabilizer, an antioxidant, a dispersant, an anti-aging agent, an accelerator, a vulcanizer, and a cold-resistant plasticizer to obtain a mixed material; and the mixed material is prepared into the low-temperature resistant rubber sealing ring material.

8. The method for preparing a low temperature and oil resistant rubber sealing ring material according to claim 7, characterized in that: In the step S1, the mass ratio of the high-purity multilayer graphene oxide, the diatomaceous earth, the silane coupling agent KH570, and the calcium stearate is 1:1-3:0.01-0.05:0.03-0.

2.

9. The method for preparing a low temperature and oil resistant rubber sealing ring material according to claim 8, characterized in that: In the step S3, the amounts of the components used are, by weight, 70-80 parts of the polyethylene, 10-20 parts of the polypropylene wax, 3-10 parts of the material A, 1-3 parts of the nano-titanium dioxide, and 1-5 parts of the nano-calcium carbonate.

10. The method for preparing a low temperature and oil resistant rubber sealing ring material according to claim 9, characterized in that: In step S4, the mass proportions of the components are: 60-70 parts of the nitrile rubber, 10-20 parts of the butadiene rubber, 10-30 parts of the EPDM rubber, 3-7 parts of the material B, and 1-3 parts of the material C.

11. The method for preparing a low temperature and oil resistant rubber sealing ring material according to claim 10, characterized in that: In the step S5, the mass proportions of the components are: 100 parts of the mixed rubber material D, 2-5 parts of the active stabilizer, 1-3 parts of the antioxidant, 1-3 parts of the dispersant, 2-5 parts of the antioxidant, 1-3 parts of the accelerator, 1-3 parts of the vulcanizer, and 10-40 parts of the cold-resistant plasticizer.

12. The method for preparing a low temperature and oil resistant rubber sealing ring material according to claim 11, characterized in that: In the step S5, the active stabilizer is zinc oxide and stearic acid, the antioxidant is antioxidant 168, the dispersant is a saturated fatty acid dispersant, the antioxidant is N-(4-anilinophenyl)acetamide NLB, the accelerator is dipentamethylenethiuram tetrasulfide DPTT, and the cold-resistant plasticizer is one or more of dioctyl adipate DOA, diisodecyl adipate DIDA, dioctyl phthalate DOP, and dibutyl diglyceride TP95.

13. The method for preparing a low temperature and oil resistant rubber sealing ring material according to claim 11, characterized in that: In step S5, the vulcanizing agent is a composite vulcanization system, and the composite vulcanization system includes sulfur, p-benzoquinone dioxime, isopropylbenzene peroxide, and phenolic resin, and the mass ratio of each component is 1:0.5:0.5:0.

3.

14. The method for preparing a low temperature and oil resistant rubber sealing ring material according to claim 7, characterized in that: In the step S4, the temperature of the banburying treatment is 110-140° C., and the time of the banburying treatment is 10-30 min.

15. A low temperature resistant rubber seal ring for an oilfield mud pump, characterized in that: The method is prepared by using the material as described in any one of claims 1 to 6.

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