Self-sealing composite rubber as well as preparation method and application thereof

Abstract

The invention discloses self-sealing composite rubber as well as a preparation method and application thereof. The self-sealing composite rubber comprises an inner core and a coating layer coating the outer layer of the inner core, the inner core is rubber, a first layer in the coating layers is polydopamine, the inner core is coated with the first layer, a second layer in the coating layers is silane coupling agent grafted polydopamine, the first layer is coated with the second layer, a third layer in the coating layers is silane coupling agent grafted water-swellable rubber, the third layer in the coating layers is silane coupling agent grafted water-swellable rubber, the fourth layer in the coating layers is silane coupling agent grafted water-swellable rubber, and the fifth layer in the coating layers is silane coupling agent grafted water-swellable rubber. And the third layer is coated on the second layer. The self-sealing valve has the advantage of self-sealing, is suitable for valve sealing of water and water-based liquid media, and reduces the risk of environmental pollution caused by leakage. And meanwhile, medium erosion, abrasion and aging can be effectively resisted, so that the service life of a valve sealing element is prolonged, and the maintenance cost is reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of valves for the petroleum industry and relates to a self-sealing composite rubber as well as a preparation method and application thereof. BACKGROUND

[0002] In recent years, with the continuous growth of global energy demand, the demand for energy has shown an unprecedented growth trend. As an important pillar of energy supply, the petroleum industry has become the focus of attention both inside and outside the industry in terms of production efficiency and safety. Against this background, the demand for valves for the petroleum industry has not only increased significantly in quantity but also put forward higher requirements in quality, especially the sealing performance of the valves, which is directly related to the stability, efficiency and environmental protection of the production process.

[0003] Valves for the petroleum industry, as important equipment for controlling oil and gas flow and ensuring smooth production processes, play a crucial role in various aspects of the petroleum industry. The sealing performance is directly related to the resource utilization efficiency, continuous and stable operation of the production line and the effectiveness of environmental protection in the petroleum production process. However, in actual applications, valves often leak in water and water-based liquid media, which not only causes waste of resources but also may cause environmental pollution, equipment damage and even production safety accidents, bringing huge economic losses and social impacts to enterprises. Therefore, ensuring zero leakage of valves, i.e., how to improve the sealing performance of valves, is a common goal pursued by academia and industry.

[0004] The sealing performance of valves for the petroleum industry is closely related to the sealing performance of the sealing material. Soft sealing is widely used due to its wide application range and good corrosion resistance. Soft sealing often uses rubber sealing, but in water and water-based liquid media, it often shows deficiencies. The existing soft sealing rubber does not have the functions of water absorption and water resistance, and cannot realize the self-sealing process, so the valve is prone to leakage. Therefore, it is urgent to develop a rubber that can self-seal in water and water-based liquid media to solve the problem of valve leakage caused by soft sealing. SUMMARY

[0005] The purpose of the present application is to provide a self-sealing composite rubber as well as a preparation method and application thereof, which solves the problem of valve leakage in water and water-based liquid media caused by existing soft sealing.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0007] A self-sealing composite rubber, comprising a core and a coating layer wrapped around the outer layer of the core.

[0008] The core is rubber, the first layer in the coating layer is polydopamine, the first layer is coated on the core, the second layer in the coating layer is silane coupling agent grafted polydopamine, the second layer is coated on the first layer, and the third layer in the coating layer is silane coupling agent grafted water-absorbing and swelling rubber, and the third layer is coated on the second layer.

[0009] Further, the rubber of the core is natural rubber or synthetic rubber.

[0010] The dopamine is hydrochloric acid dopamine.

[0011] The silane coupling agent is KH570.

[0012] The raw materials of the water-absorbing and swelling rubber include rubber, acrylamide, acrylic acid, 2-acrylamido-2-methylpropane sulfonic acid, N,N'-methylene acrylamide and ammonium sulfate.

[0013] A preparation method of the self-sealing composite rubber comprises the following steps:

[0014] The rubber is placed in a Tris-HCl buffer solution, hydrochloric acid dopamine is added dropwise, and after stirring and reaction, the solid is collected to obtain system A.

[0015] The silane coupling agent is dissolved in petroleum ether, and then added dropwise into system A, and then condensed and refluxed, and after stirring and reaction, the solid-liquid two phases are kept to obtain system B.

[0016] The rubber powder, acrylamide, acrylic acid, 2-acrylamido-2-methylpropane sulfonic acid, N,N'-methylene acrylamide and ammonium sulfate are stirred and mixed to obtain system C.

[0017] System C is slowly placed in system B, and after stirring and reaction, the self-sealing composite rubber is obtained.

[0018] Further, the mass of the hydrochloric acid dopamine is 10% of the mass of the rubber.

[0019] Further, the reaction temperature of system A is 60°C, and the stirring and reaction time is 24h.

[0020] Further, the mass of the silane coupling agent is 10% of the mass of the rubber.

[0021] Further, the condensation and reflux temperature of system B is 40°C, and the stirring and reaction time is 4h.

[0022] Further, the mass ratio of the rubber powder, acrylamide, acrylic acid, 2-acrylamido-2-methylpropane sulfonic acid, N,N'-methylene acrylamide and ammonium sulfate is 100:50:50:10:5:2, and the mass ratio of the total mass of system C to the mass of the rubber is 1:10.

[0023] Further, the reaction temperature of the system C is 60 DEG C, and the stirring reaction time is 24h.

[0024] Application of the self-sealing composite rubber in valve sealing in water or water-based liquid medium.

[0025] Compared with the prior art, the application has the following beneficial effects:

[0026] The application provides a self-sealing composite rubber, which is internally filled with rubber, the first layer of a coating layer is coated with polydopamine, the second layer of the coating layer is grafted with polydopamine by using a silane coupling agent, and the third layer of the coating layer is grafted with water-absorbing and swelling rubber by using a silane coupling agent through the second layer of the coating layer. The self-sealing composite rubber has a unique multilayer structure, and when used for valve sealing in water and water-based liquid medium, the rubber base material in the inner layer provides basic elasticity and strength. The polydopamine grafted with the silane coupling agent is used as an intermediate layer, which not only enhances the hydrophobic property of the material and prevents water from directly penetrating into the inner rubber layer, but also enhances the bonding force between the layers through coupling, thereby ensuring the stability and durability of the overall structure. The outermost water-absorbing and swelling rubber can swell rapidly after being contacted with water, tightly adhere to the sealing surface, effectively prevent water and water-based liquid from leaking, and then complete the self-sealing process, thereby achieving the valve sealing goal. The application fills the small gaps between the sealing surfaces in a soft sealing manner, thereby achieving the self-sealing effect, is suitable for valve sealing in water and water-based liquid medium, and solves the problem that the traditional sealing material is prone to failure in water and water-based liquid medium. The application is beneficial to be applied in the valve field of the petroleum industry and has a wide application prospect. Meanwhile, due to the multilayer structure and the special material combination, the composite rubber can effectively resist medium erosion, wear and aging, thereby prolonging the service life of the valve sealing element and reducing the maintenance cost. In addition, the self-sealing property reduces the environmental pollution risk caused by leakage.

[0027] The application also provides a preparation method of the self-sealing composite rubber. The self-sealing composite rubber is prepared by coating polydopamine on the core, grafting the polydopamine with a silane coupling agent, and finally grafting the water-absorbing and swelling rubber with the silane coupling agent. In the preparation process, when the silane coupling agent is grafted onto the polydopamine, the strong adhesion of the silane coupling agent is further amplified, and the polydopamine itself also has good adhesion and biocompatibility. This combination can significantly improve the adhesion between the valve material and the sealing surface, reducing the risk of leakage. The water-absorbing and swelling rubber can quickly absorb water and swell when it comes into contact with water or water-based liquid. When the silane coupling agent is grafted onto the water-absorbing and swelling rubber, it can further improve the uniformity and speed of water absorption and swelling, thereby ensuring that the valve can quickly and tightly fit the sealing surface during the sealing process, improving the overall strength of the valve, and enabling the valve to maintain stable sealing performance when subjected to pressure or temperature changes. The addition of the silane coupling agent can also improve the anti-aging performance of the rubber material, reducing material aging and performance degradation caused by long-term use or environmental factors, which is conducive to maintaining the long-term stability of the valve sealing performance and prolonging the service life of the valve.

[0028] Further, in the preparation of system A, Tris-HCl buffer solution is used as the solvent for the rubber. The Tris-HCl buffer solution has excellent buffering capacity and can resist changes in pH caused by external factors, providing a stable pH environment to maintain the stable pH of the experimental solution.

[0029] Further, in the preparation of system B, petroleum ether is used as the solvent for the silane coupling agent. Since petroleum ether has a low boiling point and strong volatility, it is easier to evaporate during the reaction process, which helps to reduce the impact of solvent residues on the final product and also helps to reduce safety hazards during operation.

[0030] Further, KH570 is used as the silane coupling agent. The molecular structure of KH570 contains an unsaturated double bond structure of a methacryloyloxy functional group and three hydrolyzable methoxy functional groups. This dual reactivity allows it to significantly improve the adhesion strength between the valve material and the sealing surface through bidirectional chemical reactions, thereby improving the sealing performance of the self-sealing composite rubber material. DETAILED DESCRIPTION

[0031] To enable those skilled in the art to understand the characteristics and effects of the present application, the following is a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific words used herein have their usual meanings understood by those skilled in the art of the present application, and in case of conflict, the definitions in the specification shall prevail.

[0032] Theories and explanations presented and disclosed herein, whether or not covered by the scope of the present application, should not be taken as limiting the scope of the present application, i.e., the present application can be practiced without regard to any particular theory or mechanism.

[0033] Herein, all features described and disclosed in terms of numerical ranges or percentage ranges are for the convenience of the reader only. Thus, the description of numerical ranges or percentage ranges should be considered as having specifically disclosed all possible sub-ranges and individual numerical values (both integers and fractions) within the range.

[0034] Herein, unless otherwise stated, "comprise", "comprising", "include", "including", "contain", "containing", "have", "having", or the like, are taken to mean "consist of and / or "consist essentially of" for the convenience of the reader only, e.g., "A comprises a" is taken to mean "A comprises a and other" and "A consists of a" for the convenience of the reader only.

[0035] Herein, for the sake of brevity, not all possible combinations of the various technical features in the various embodiments or examples are described. Therefore, any combination of the various technical features in the various embodiments or examples is possible, as long as the combination does not result in a contradiction, and all possible combinations are to be considered as being within the scope of the present disclosure.

[0036] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the embodiments of the present application. In combination with the specific embodiments, the present application is further described, and it should be understood that these embodiments are only used for illustrating the present application and not for limiting the scope of the present application, and the described embodiments are part of the embodiments of the present application, but not all the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. In addition, it should be understood that after reading the content taught by the present application, those skilled in the art can make various modifications or changes to the present application, and these equivalent forms also fall within the scope defined by the appended claims of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of the present application.

[0037] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the skilled person in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples without contradiction.

[0038] In order to make the skilled in the art more clearly understand the technical solutions described in the present application, the following examples are given for illustration. It should be noted that the following examples do not constitute a limitation on the scope of protection required by the present application. The raw materials, reagents or devices used in the following examples, unless otherwise specified, can be obtained from conventional commercial channels, or can be obtained by existing known methods. The following examples use conventional instruments and equipment in the art. The experimental method in the following examples is not specified, usually according to the conventional conditions, or according to the conditions recommended by the manufacturer. Various raw materials are used in the following examples, unless otherwise specified, all use conventional commercially available products, the specifications are conventional specifications in the art. In the specification of the present application and the following examples, unless otherwise specified, "%" means weight percent, "parts" means weight parts, and the ratio means weight ratio.

[0039] The present application is further described below:

[0040] The present application provides a self-sealing composite rubber, comprising a core and a cladding layer, the cladding layer is wrapped outside the core. The self-sealing composite rubber is that the rubber is used as the core, the first layer in the cladding layer is coated with polydopamine, the first layer is coated on the core, the second layer in the cladding layer is grafted with silane coupling agent on polydopamine, the second layer is coated on the first layer, and the third layer in the cladding layer is grafted with silane coupling agent on water-absorbing and expanding rubber through the second layer, and the third layer is coated on the second layer.

[0041] The core material is rubber, the core serves as a mechanical support material and a matrix, and the rubber of the core is natural rubber or synthetic rubber; the first layer in the coating layer is coated with polydopamine, which means that the polydopamine is loaded on the periphery of the core rubber by using a polydopamine polymerization reaction; the second layer in the coating layer is grafted with polydopamine by using a silane coupling agent, which means that the silane coupling agent is grafted with polydopamine by using a condensation reaction between the hydroxyl groups of the silane coupling agent and the hydroxyl groups of polydopamine; and the third layer in the coating layer is grafted with water-absorbing and swelling rubber by using a silane coupling agent in the second layer, which means that the water-absorbing and swelling rubber generated in situ is grafted on the silane coupling agent by using the raw materials for preparing the water-absorbing and swelling rubber.

[0042] Preferably, the dopamine is dopamine hydrochloride; the silane coupling agent is KH570; the raw materials for preparing the water-absorbing and swelling rubber are rubber, acrylamide (AM), acrylic acid (AA), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), N,N'-methylene acrylamide (BIS) and ammonium sulfate; and the rubber in the raw materials for preparing the water-absorbing and swelling rubber includes natural rubber and synthetic rubber.

[0043] Preferably, the synthetic rubber includes concentrated latex, styrene-butadiene rubber, cis-butadiene rubber, butyl rubber and nitrile rubber.

[0044] The application further provides a preparation method of the self-sealing composite rubber, which specifically comprises the following steps:

[0045] (1) A certain amount of rubber is weighed as the core, and is completely dissolved in a Tris-HCl buffer solution; dopamine hydrochloride with a mass of 10% of the core is added dropwise into the solution, and is stirred and reacted at 60 DEG C for 24 h; after filtration, the solid is collected to obtain system A for standby;

[0046] (2) A silane coupling agent with a mass of 10% of the rubber in the core is completely dissolved in petroleum ether, and is then added dropwise into system A; after condensation reflux and stirring at 40 DEG C for 4 h, the solid-liquid two phases are kept to obtain system B for standby;

[0047] (3) Another amount of rubber is subjected to high-energy ball milling to obtain rubber powder for standby;

[0048] (4) The rubber powder, AM, AA, AMPS, BIS and ammonium sulfate are mixed by stirring according to a mass ratio of 100:50:50:10:5:2, and the stirring time is 10 h to obtain system C for standby;

[0049] (5) System C is slowly placed in system B according to a mass ratio of the total mass of system C to the mass of the rubber in the core of 1:10, and is kept stirring at 60 DEG C for 24 h; after the stirring is completed, the self-sealing composite rubber is obtained.

[0050] Examples

[0051] The present application further explains and illustrates the self-sealing composite rubber and the preparation method and application thereof by providing multiple embodiments.

[0052] Example 1:

[0053] 1000g of solid natural rubber was weighed as the core, which was completely dissolved in 10L of Tris-HCl buffer solution, and then 100g of dopamine hydrochloride was added dropwise into the buffer solution, and the reaction was stirred at 60°C for 24h. After filtration, the solid was collected to obtain system A for standby;

[0054] 100g of KH570 was completely dissolved in 1L of petroleum ether, and then added dropwise into system A, and the reaction was stirred at 40°C under condensation reflux for 4h, and the solid-liquid two phases were maintained to obtain system B for standby;

[0055] Another 1500g of butyl nitrile rubber was subjected to high-energy ball milling to obtain butyl nitrile rubber powder for standby;

[0056] 1000g of butyl nitrile rubber powder, 500g of AM, 500g of AA, 100g of AMPS, 50g of BIS and 20g of ammonium sulfate were weighed and stirred for 10h to obtain system C for standby;

[0057] 100g of system C was slowly placed in system B, and the stirring was maintained at 60°C for 24h. After the stirring was completed, the self-sealing composite rubber was obtained.

[0058] Example 2:

[0059] Different from example 1, the core used in this embodiment is concentrated latex.

[0060] Example 3:

[0061] Different from example 1, the core used in this embodiment is styrene butadiene rubber.

[0062] Example 4:

[0063] Different from example 1, the core used in this embodiment is cis-butadiene rubber.

[0064] Example 5:

[0065] Different from example 1, the core used in this embodiment is butyl rubber.

[0066] Example 6:

[0067] Different from example 1, the core used in this embodiment is butyl nitrile rubber.

[0068] The self-sealing composite rubber prepared in Examples 1-6 was subjected to water immersion expansion rate test and valve sealing performance test, and the performance test results are shown in Table 1.

[0069] Table 1 Performance of samples obtained in Examples 1-6

[0070] Test item Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 1-time water immersion expansion rate (%) 468 475 525 542 537 560 3-time water immersion expansion rate (%) 471 472 561 572 566 581 10-time water immersion expansion rate (%) 472 472 562 572 567 581 20-time water immersion expansion rate (%) 474 478 562 573 568 581 Valve sealing test No leakage No leakage No leakage No leakage No leakage No leakage

[0071] As can be seen from the test results in Table 1, the self-sealing composite rubber prepared in Examples 1-6 has an expansion rate of more than 450% after one-time and multiple water immersion, and the valve sealing experiment results are no leakage, indicating that the self-sealing composite rubber prepared by the present application can effectively improve the sealing performance of the valve, proving the high reliability of the self-sealing composite rubber in practical application, its high sealing performance, stable material properties and convenient preparation process have the potential to be widely used in practical petroleum industry environment.

[0072] Compared with the prior art, the self-sealing composite rubber prepared by the preparation method of the present application is used for valve sealing of water and water-based liquid medium, the self-sealing composite rubber achieves water absorption and water blocking by water absorption and expansion, and completes the self-sealing process, thereby realizing the goal of reliable sealing of the valve. The present application has the advantage of self-sealing, and once it comes into contact with water or water-based liquid, the outermost water absorption and expansion rubber will quickly respond, absorb water and expand in volume. This expansion process not only closely fits the sealing surface of the valve, eliminating potential leakage paths, but also enhances the soft sealing effect through physical compression, ensuring zero leakage performance of the valve under various working conditions and improving the overall stability and reliability of the system. It is beneficial to be applied in the field of petroleum industry valves and has broad application prospects.

[0073] The above is only the preferred embodiment of the present application, which shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above embodiments, and the above embodiments and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A self-sealing composite rubber, characterized in that, Includes the kernel and the wrapper layer that covers the kernel; The core is rubber, the first layer of the coating layer is polydopamine, which is coated on the core, the second layer of the coating layer is polydopamine grafted with a silane coupling agent, which is coated on the first layer, and the third layer of the coating layer is water-absorbing and swelling rubber grafted with a silane coupling agent, which is coated on the second layer.

2. The self-sealing composite rubber according to claim 1, characterized in that, The rubber in the core is natural rubber or synthetic rubber; The dopamine in question is dopamine hydrochloride; The silane coupling agent is KH570; The raw materials for the water-absorbing and swelling rubber include rubber, acrylamide, acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, N,N'-methyleneacrylamide, and ammonium sulfate.

3. A method for preparing the self-sealing composite rubber according to claim 1 or 2, characterized in that, include: Rubber was placed in a Tris-HCl buffer solution, dopamine hydrochloride was added dropwise to it, the reaction was stirred and the solid was collected to obtain system A; The silane coupling agent was dissolved in petroleum ether and added dropwise to system A. The mixture was refluxed and stirred to maintain a solid-liquid two-phase system to obtain system B. Rubber powder, acrylamide, acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, N,N'-methyleneacrylamide, and ammonium sulfate were stirred and mixed to obtain system C; System C was slowly placed into system B, and after stirring and reacting, a self-sealing composite rubber was obtained.

4. The method for preparing the self-sealing composite rubber according to claim 3, characterized in that, The mass of the dopamine hydrochloride is 10% of the mass of the rubber.

5. The method for preparing the self-sealing composite rubber according to claim 3, characterized in that, The reaction temperature of system A is 60℃, and the stirring reaction time is 24h.

6. The method for preparing the self-sealing composite rubber according to claim 3, characterized in that, The mass of the silane coupling agent is 10% of the rubber.

7. The method for preparing the self-sealing composite rubber according to claim 3, characterized in that, The reflux temperature of system B is 40°C, and the stirring reaction time is 4 hours.

8. The method for preparing the self-sealing composite rubber according to claim 3, characterized in that, The mass ratio of the rubber powder, acrylamide, acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, N,N'-methyleneacrylamide, and ammonium sulfate is 100:50:50:10:5:2, and the total mass ratio of system C to the mass ratio of the rubber is 1:

10.

9. The method for preparing the self-sealing composite rubber according to claim 3, characterized in that, The reaction temperature of system C and system B is 60℃, and the stirring reaction time is 24h.

10. The application of the self-sealing composite rubber according to claim 1 or 2 in valve sealing for water or water-based liquid media.