Seawater-corrosion-resistant oil seal rubber composition as well as preparation method and application thereof

Abstract

The invention discloses a seawater-corrosion-resistant oil seal rubber composition and a preparation method and application thereof, and the composition comprises the following components in parts by weight: 85-95 parts of hydrogenated nitrile rubber, 5-15 parts of fluororubber, 20-55 parts of a reinforcing agent, 3-6 parts of a silane coupling agent, 4-8 parts of an active agent, 2-4 parts of an anti-aging agent, 1-3 parts of an accelerant and 3-6 parts of a vulcanizing agent. Through reasonable formula design, the rubber composition has excellent material mechanical properties, fatigue resistance and aging resistance under the condition of ensuring that equipment working in seawater does not leak oil, the tensile strength of the rubber composition reaches 22 MPa or above, and the elongation at break reaches 550% or above, so that an oil seal sealing element has various excellent properties, and the service life of the oil seal sealing element is prolonged. The device is well applied to steamships and ship washing equipment. Meanwhile, the raw materials are simple and easy to obtain, the process is simple, the cost is low, and popularization and application in mass production are facilitated.

Description

Technical Field

[0001] This invention belongs to the field of rubber composition technology, and specifically relates to an oil seal rubber composition resistant to seawater corrosion, its preparation method, and its application. Background Technology

[0002] The main material of a ship's hull is steel, which slowly reacts with oxygen in a humid environment and rusts. Therefore, to protect it, a layer of paint is applied to the outside to block seawater and air. However, over time, the protective coating gradually wears off due to water currents, erosion, and sand. Oxygen-rich, high-salt seawater forms galvanic cells with the steel, causing the hull to oxidize and rust. The resulting rust is porous, increasing the contact area between oxygen and iron, thus accelerating corrosion. Furthermore, oysters and other shellfish, due to their tendency to attach themselves to the hull, secrete substances that corrode the hull and clog pipes. Under the influence of these factors, the ship's originally sturdy metal hull becomes fragile, prone to leaks, and more easily damaged by rocks and other debris. Therefore, regularly cleaning the ship to remove rust and attached shellfish is crucial for maintaining its lifespan.

[0003] Traditional ship cleaning methods involve manual cleaning, which requires tools such as brushes and shovels to scrape off attached oyster shells and rust patches. However, for giant ships that often weigh tens of thousands of tons, manual cleaning is slow and inefficient. Moreover, manual cleaning with shovels can easily cause uneven force, creating deep and shallow scratches on the hull, thus causing secondary damage.

[0004] Therefore, high-pressure water jet cleaning technology, namely high-pressure water washing machines, was developed. Since these machines operate in seawater for extended periods, the technical requirements for their oil seals are high. Currently available oil seals have poor corrosion resistance and short service life.

[0005] Chinese patent, publication number CN106750686A, entitled "A Seawater Corrosion-Resistant Sealing Component for Ships and its Preparation Method," incorporates an organotin compound, which prevents marine organisms from adhering to the rubber and significantly improves the seawater corrosion resistance of the rubber sealing component. However, in the prior art, organotin compounds are highly polluting to seawater and have been banned.

[0006] Chinese Patent, Publication No. CN114561048A, entitled "A Natural Rubber-Chloroprene Rubber Composition for Seawater-Resistant Rubber Bearings and Its Preparation Method and Uses," describes a composition with excellent salt water resistance, heat aging resistance, and low-temperature resistance. However, this rubber composition is only suitable for rubber bearings in a static state and is not applicable to oil seals on ship washing machines. Oil seals operate under dynamic friction and require certain properties such as wear resistance, oil resistance, and sealing. Summary of the Invention

[0007] To address the problems in the prior art, this invention provides a rubber composition for oil seals with excellent mechanical properties, good processing performance, excellent fatigue resistance, and excellent seawater corrosion resistance, as well as its preparation method and application.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A seawater-resistant oil seal rubber composition, by weight, comprising: 85-95 parts hydrogenated nitrile rubber, 5-15 parts fluororubber, 20-55 parts reinforcing agent, 3-6 parts silane coupling agent, 4-8 parts activator, 2-4 parts antioxidant, 1-3 parts accelerator, and 3-6 parts vulcanizing agent.

[0010] This invention reveals that, through the above formulation, while ensuring the wear resistance and good sealing performance of oil seals for ship washing machines, the material mechanical properties, fatigue resistance, and seawater corrosion resistance of the rubber composition can be further improved. Hydrogenated nitrile butadiene rubber (HNBR) itself possesses excellent physical and mechanical properties and oil resistance; furthermore, due to its highly saturated structure, it exhibits good heat resistance, excellent chemical corrosion resistance, superior ozone resistance, and high compression set resistance. Simultaneously, HNBR also features high strength, high tear resistance, and excellent abrasion resistance, making it one of the rubbers with extremely outstanding comprehensive performance. However, its resistance to acids and polar solvents is relatively poor; fluororubber can compensate for this shortcoming of HNBR.

[0011] Silane coupling agents are mainly composed of organosilicon. The main chain of organosilicon is very flexible, and its intermolecular forces are much weaker than those of hydrocarbons. Therefore, it has lower viscosity, weaker surface tension, and lower surface energy than hydrocarbons of the same molecular weight. On the one hand, it can increase the compatibility of organic and inorganic materials; on the other hand, it can prevent marine organisms from adhering to rubber, thus greatly improving the seawater corrosion resistance of rubber seals.

[0012] As a preferred embodiment, the hydrogenated nitrile rubber is Zetpol 1000 hydrogenated nitrile rubber from Zeon Corporation of Japan, with an acrylonitrile content of 49 wt%, Mooney viscosity of 66, and a degree of hydrogenation of 99%.

[0013] As a preferred embodiment, the fluororubber is DuPont's Kalrez0040.

[0014] As a preferred embodiment, the reinforcing agent comprises carbon black, silica, and calcium oxide in a mass ratio of (10~30):(5~15):(5~10).

[0015] As a preferred embodiment, the carbon black is high abrasion-resistant carbon black N330.

[0016] As a preferred embodiment, the BET surface area of ​​the silica, measured using nitrogen, is 120–200 m². 2 / g, the absorbance of dibutyl phthalate is 2.00–3.50 cm⁻¹. 3 / g, and when the silica is dispersed in water to form a 5 wt% aqueous solution, the pH value is 5.0 to 8.0.

[0017] As a preferred embodiment, the calcium oxide is generally required to have a fineness of about 500~1250 mesh, a whiteness of 90, an abrasion value of 8~20 mg / 2000 times, a CaO purity of 98% (mass percentage), and low levels of impurities such as silicon, aluminum, and iron.

[0018] As a preferred embodiment, the silane coupling agent is KH550, KH560, KH570, or KH580.

[0019] As a preferred embodiment, the activator comprises nano zinc oxide and stearic acid in a mass ratio of (2~5):(2~3).

[0020] As a preferred embodiment, the nano zinc oxide comprises 80 wt% primary particles with a particle size of less than 100 nm and 20 wt% primary particles with a particle size of more than 100 nm.

[0021] As a preferred embodiment, the antioxidant comprises antioxidant MB and antioxidant H in a mass ratio of (1~3):(1~2).

[0022] As a preferred embodiment, the accelerator comprises accelerator TT and accelerator DM in a mass ratio of (0.5~1):(0.5~2).

[0023] As a preferred embodiment, the vulcanizing agent comprises vulcanizing agent DCP, vulcanizing agent magnesium oxide, and vulcanizing agent No. 3 in a mass ratio of (2~3):(0.5~2):(0.5~1).

[0024] As a preferred embodiment, a seawater-resistant oil seal rubber composition, by weight, comprises:

[0025]

[0026] This invention uses hydrogenated nitrile butadiene rubber and fluororubber together to prepare a rubber composition for oil seals that is resistant to seawater corrosion and possesses various excellent properties. Furthermore, the addition of a silane coupling agent increases the compatibility between organic and inorganic materials and prevents marine organisms from adhering to the rubber, thus significantly improving the seawater corrosion resistance of the rubber seals.

[0027] A method for preparing a seawater-resistant oil seal rubber composition includes the following steps:

[0028] First, the hydrogenated nitrile rubber and fluororubber are plasticized separately. Then, the two plasticized rubbers are mixed evenly in the first mixing process. All compounding agents except for the vulcanization system are added for the second mixing process. The rubber is discharged at 120-130 °C to obtain the masterbatch.

[0029] The masterbatch is mixed with the compounding agents of the vulcanization system in a third mixing process, and the rubber is discharged at 115-125°C to obtain the final rubber.

[0030] As a preferred embodiment, the "all compounding agents other than the vulcanization system" include reinforcing agents, activators, and antioxidants, and the "compounding agents of the vulcanization system" include vulcanizing agents and accelerators.

[0031] As a preferred embodiment, the first mixing time is 1 to 2 minutes; the second mixing time is 3 to 4 minutes; and the third mixing time is 2 to 3 minutes.

[0032] As a preferred option, after obtaining the masterbatch, the rubber sheets are left to stand for 4 to 8 hours before proceeding with the third mixing process.

[0033] As a preferred embodiment, the first mixing, the second mixing, and the third mixing are all carried out in an internal mixer.

[0034] Application of a seawater-resistant oil seal rubber composition, wherein the rubber composition is used to prepare rubber molded articles.

[0035] As a preferred embodiment, the rubber composition is vulcanized to obtain a rubber molded body; the vulcanization temperature is 165~175℃; and the vulcanization time is 5~15min.

[0036] As a preferred embodiment, the rubber molded body is used in ships, ship washing equipment, offshore drilling platform equipment, bridge bearings, and offshore power generation equipment.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] This invention, through rational formulation design, enables the rubber composition to achieve excellent material mechanical properties, fatigue resistance, and aging resistance while ensuring oil-free operation of equipment in seawater. Its tensile strength exceeds 22 MPa, and its elongation at break exceeds 550%, thus giving the oil seal a combination of superior performance characteristics, making it well-suited for use in ships and ship washing equipment. Furthermore, the raw materials used in this invention are simple and readily available, the process is straightforward, and the cost is low, facilitating its widespread application in mass production. Detailed Implementation

[0039] The present invention will be further described below with reference to embodiments.

[0040] The silica used in the following examples was commercially available and met the following parameters: BET surface area measured with nitrogen was 120–200 m². 2 / g, the absorbance of dibutyl phthalate is 2.00–3.50 cm⁻¹. 3 / g, and when the silica is dispersed in water to form a 5wt% aqueous solution, its pH value is 5.0 to 8.0.

[0041] The nano zinc oxide used in the following examples includes 80 wt% primary particles with a particle size of less than 100 nm and 20 wt% primary particles with a particle size of more than 100 nm.

[0042] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased through legitimate channels.

[0043] Example 1

[0044] This embodiment 1 first provides an oil seal rubber composition resistant to seawater corrosion, wherein, by weight, the rubber composition comprises:

[0045]

[0046] Example 1 further provides a method for preparing the above-mentioned rubber composition, comprising the following steps: adding hydrogenated nitrile rubber and fluororubber to a mixer for sequential plasticizing; mixing the plasticized hydrogenated nitrile rubber, fluororubber, carbon black, silica, and all compounding agents except for the vulcanization system for 3 minutes; then discharging the rubber at 125°C to obtain the masterbatch; after the rubber sheet has been left to stand for 8 hours, adding the masterbatch and all compounding agents of the vulcanization system to a mixer for 2 minutes; and discharging the rubber at 120°C to obtain the final compound.

[0047] The sample was vulcanized using a steam flat vulcanizing machine under the following conditions: temperature 170℃, time 10 min.

[0048] Example 2

[0049] This embodiment 2 first provides a seawater-resistant oil seal rubber composition, which, by weight, comprises:

[0050]

[0051] Example 2 further provides a method for preparing the above-mentioned rubber composition, including the following steps: adding hydrogenated nitrile rubber and fluororubber to a mixer for sequential plasticizing; mixing the plasticized hydrogenated nitrile rubber, fluororubber, carbon black, silica, and all compounding agents except for the vulcanization system for 3 minutes; then discharging the rubber at 125°C to obtain the masterbatch; after the rubber sheet has been left to stand for 8 hours, adding the masterbatch and all compounding agents of the vulcanization system to a mixer for 2 minutes; and discharging the rubber at 120°C to obtain the final compound.

[0052] The sample was vulcanized using a steam flat vulcanizing machine under the following conditions: temperature 170℃, time 10 min.

[0053] Example 3

[0054] This embodiment 3 first provides an oil seal rubber composition resistant to seawater corrosion, wherein, by weight, the rubber composition comprises:

[0055]

[0056] Example 3 further provides a method for preparing the above-mentioned rubber composition, including the following steps: adding hydrogenated nitrile rubber and fluororubber to a mixer for sequential plasticizing; mixing the plasticized hydrogenated nitrile rubber, fluororubber, carbon black, silica, and all compounding agents except for the vulcanization system for 3 minutes; then discharging the rubber at 125°C to obtain the masterbatch; after the rubber sheet has been left to stand for 8 hours, adding the masterbatch and all compounding agents of the vulcanization system to a mixer for 2 minutes; discharging the rubber at 120°C to obtain the final compound.

[0057] The sample was vulcanized using a steam flat vulcanizing machine under the following conditions: temperature 170℃, time 10 min.

[0058] Example 4

[0059] This embodiment 4 first provides a seawater-resistant oil seal rubber composition, which, by weight, comprises:

[0060]

[0061] Example 4 further provides a method for preparing the above-mentioned rubber composition, comprising the following steps: adding hydrogenated nitrile rubber and fluororubber to a mixer for sequential plasticizing; mixing the plasticized hydrogenated nitrile rubber, fluororubber, carbon black, silica, and all compounding agents except for the vulcanization system for 3 minutes; then discharging the rubber at 125°C to obtain the masterbatch; after the rubber sheet has been left to stand for 8 hours, adding the masterbatch and all compounding agents of the vulcanization system to a mixer for 2 minutes; and discharging the rubber at 120°C to obtain the final compound.

[0062] The sample was vulcanized using a steam flat vulcanizing machine under the following conditions: temperature 170℃, time 10 min.

[0063] Example 5

[0064] This embodiment 5 first provides an oil seal rubber composition resistant to seawater corrosion, wherein, by weight, the rubber composition comprises:

[0065]

[0066] Example 5 further provides a method for preparing the above-mentioned rubber composition, comprising the following steps: adding hydrogenated nitrile rubber and fluororubber to a mixer for sequential plasticizing; mixing the plasticized hydrogenated nitrile rubber, fluororubber, carbon black, silica, and all compounding agents except for the vulcanization system for 3 minutes; then discharging the rubber at 125°C to obtain the masterbatch; after the rubber sheet has been left to stand for 8 hours, adding the masterbatch and all compounding agents of the vulcanization system to a mixer for 2 minutes; and discharging the rubber at 120°C to obtain the final compound.

[0067] The sample was vulcanized using a steam flat vulcanizing machine under the following conditions: temperature 170℃, time 10 min.

[0068] Comparative Example 1

[0069] This comparative example provides a rubber composition that differs from Example 1 in that the type of raw rubber is different, and the corresponding compounding agents are different, specifically:

[0070]

[0071] Comparative Example 1 further provides a method for preparing the above-mentioned rubber composition, comprising the following steps: adding hydrogenated nitrile rubber to a mixer for plasticizing, mixing the plasticized hydrogenated nitrile rubber, carbon black, silica, and all compounding agents except for the vulcanization system for 3 minutes, and then discharging the rubber at a temperature of 125°C to obtain a masterbatch; after the rubber sheet has been left to stand for 8 hours, adding the masterbatch and all compounding agents of the vulcanization system to a mixer, mixing for 2 minutes, and discharging the rubber at a temperature of 120°C to obtain a final compound.

[0072] The sample was vulcanized using a steam flat vulcanizing machine under the following conditions: temperature 170℃, time 10 min.

[0073] Comparative Example 2

[0074] Comparative Example 2 provides a rubber composition, the formulation of which is as follows, by weight:

[0075]

[0076] Comparative Example 2 further provides a method for preparing the above-mentioned rubber composition, comprising the following steps: adding hydrogenated nitrile rubber and fluororubber to a mixer for sequential plasticizing; mixing the plasticized hydrogenated nitrile rubber, fluororubber, carbon black, silica, and all compounding agents except for the vulcanization system for 3 minutes; then discharging the rubber at 125°C to obtain the masterbatch; after the rubber sheet has been left to stand for 8 hours, adding the masterbatch and all compounding agents of the vulcanization system to a mixer for 2 minutes; and discharging the rubber at 120°C to obtain the final compound.

[0077] The sample was vulcanized using a steam flat vulcanizing machine under the following conditions: temperature 170℃, time 10 min.

[0078] Experimental Example

[0079] The performance of the rubber compositions in the examples and comparative examples was tested according to national standards (Shore A hardness reference standard: GB / T6031-2017 Determination of hardness of vulcanized rubber or thermoplastic rubber; Tensile strength, elongation at break, and tear strength reference standard: GB / T 528-92 Determination of tensile properties of vulcanized rubber and thermoplastic rubber; Salt spray aging test reference standard: GB / T 35858-2018 Salt spray aging test method for vulcanized rubber). The specific performance test results of Examples 1-3 and Comparative Examples 1 and 2 are shown in Table 1.

[0080] Table 1

[0081]

[0082] As can be seen from Table 1, when nitrile rubber and fluororubber are used together, the mechanical properties of the compound (including tensile strength, tear strength, elongation at break, etc.) are better. The addition of silane coupling agent can improve the mechanical properties and salt spray aging resistance of the compound.

[0083] As an application of the oil seal rubber composition in this invention, the rubber molded body is used in equipment such as ships, ship washing machines, offshore drilling platform equipment, bridge bearings, and offshore power generation, especially oil seals on ship washing machines.

[0084] This invention reveals that, through the above formulation, while ensuring the wear resistance and good sealing performance of oil seals for ship washing machines, the material mechanical properties, fatigue resistance, and seawater corrosion resistance of the rubber composition can be further improved. Hydrogenated nitrile butadiene rubber (HNBR) itself possesses excellent physical and mechanical properties and oil resistance; furthermore, due to its highly saturated structure, it exhibits good heat resistance, excellent chemical corrosion resistance, superior ozone resistance, and high compression set resistance. Simultaneously, HNBR also features high strength, high tear resistance, and excellent abrasion resistance, making it one of the rubbers with extremely outstanding comprehensive performance. However, its resistance to acids and polar solvents is relatively poor; fluororubber can compensate for this shortcoming of HNBR.

[0085] Silane coupling agents are mainly composed of organosilicon. The main chain of organosilicon is very flexible, and its intermolecular forces are much weaker than those of hydrocarbons. Therefore, it has lower viscosity, weaker surface tension, and lower surface energy than hydrocarbons of the same molecular weight. On the one hand, it can increase the compatibility of organic and inorganic materials; on the other hand, it can prevent marine organisms from adhering to rubber, thus greatly improving the seawater corrosion resistance of rubber seals.

[0086] This invention uses hydrogenated nitrile butadiene rubber and fluororubber together to prepare a rubber composition for oil seals that is resistant to seawater corrosion and possesses various excellent properties. Furthermore, the addition of a silane coupling agent increases the compatibility between organic and inorganic materials and prevents marine organisms from adhering to the rubber, thus significantly improving the seawater corrosion resistance of the rubber seals.

[0087] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A seawater-resistant oil seal rubber composition, characterized in that, The rubber composition comprises, by weight: 85-95 parts hydrogenated nitrile rubber, 5-15 parts fluororubber, 20-55 parts reinforcing agent, 3-6 parts silane coupling agent, 4-8 parts activator, 2-4 parts antioxidant, 1-3 parts accelerator, and 3-6 parts vulcanizing agent.

2. The seawater-resistant oil seal rubber composition according to claim 1, characterized in that, The hydrogenated nitrile butadiene rubber is Zetpol 1000 hydrogenated nitrile butadiene rubber from Zeon Corporation of Japan, with an acrylonitrile content of 49 wt%, Mooney viscosity of 66, and hydrogenation degree of 99%. The fluororubber is DuPont's Kalrez0040. The reinforcing agent comprises carbon black, silica, and calcium oxide in a mass ratio of (10~30):(5~15):(5~10).

3. The seawater-resistant oil seal rubber composition according to claim 2, characterized in that, The carbon black is high-abrasion-resistant carbon black N330; the BET surface area of ​​the silica, measured with nitrogen, is 120–200 m². 2 / g, the absorbance of dibutyl phthalate is 2.00–3.50 cm⁻¹. 3 / g, and when the silica is dispersed in water to form a 5wt% aqueous solution, its pH value is 5.0-8.0; the calcium oxide has a fineness of 500-1250 mesh, a whiteness of 90, an abrasion value of 8-20 mg / 2000 times, and a CaO purity of 98% by mass; The silane coupling agent is KH550, KH560, KH570, or KH580; The activator comprises nano zinc oxide and stearic acid in a mass ratio of (2~5):(2~3); The nano zinc oxide comprises 80 wt% primary particles with a particle size of less than 100 nm and 20 wt% primary particles with a particle size of more than 100 nm. The antioxidant comprises antioxidant MB and antioxidant H in a mass ratio of (1~3):(1~2); The accelerator comprises accelerator TT and accelerator DM in a mass ratio of (0.5~1):(0.5~2); The vulcanizing agent includes vulcanizing agent DCP, vulcanizing agent magnesium oxide, and vulcanizing agent No. 3 in a mass ratio of (2~3):(0.5~2):(0.5~1).

4. The seawater-resistant oil seal rubber composition according to claim 3, characterized in that, The rubber composition comprises, by weight: Hydrogenated nitrile butadiene rubber Zetpol 1000 85~95 parts, Fluororubber Kalrez0040, 5-15 parts N330 10~30 servings 5-15 parts of silica 5-10 parts calcium oxide 3-6 parts of silane coupling agent Surfactant 4-8 parts, Anti-aging agent 2-4 parts, Accelerator 1-3 parts, 3-6 parts of vulcanizing agent.

5. The method for preparing the seawater-resistant oil seal rubber composition according to any one of claims 1-4, characterized in that, Includes the following steps: First, the hydrogenated nitrile rubber and fluororubber are plasticized separately. Then, the two plasticized rubbers are mixed evenly in the first mixing. Reinforcing agent, activator and antioxidant are added for the second mixing. The rubber is discharged at 120-130℃ to obtain the masterbatch. The masterbatch is mixed with vulcanizing agent and accelerator in a third mixing process, and discharged at 115-125°C to obtain the final compound.

6. The method for preparing the seawater-resistant oil seal rubber composition according to claim 5, characterized in that, The first mixing time is 1 to 2 minutes; the second mixing time is 3 to 4 minutes; the third mixing time is 2 to 3 minutes; after obtaining the masterbatch, the rubber sheet is left to stand for 4 to 8 hours, and then the third mixing is carried out.

7. The method for preparing the seawater-resistant oil seal rubber composition according to claim 6, characterized in that, The first, second, and third mixing processes are all carried out in an internal mixer.

8. The application of the seawater-resistant oil seal rubber composition according to any one of claims 1-7, characterized in that, The rubber composition is used to prepare rubber molded articles.

9. The application of the seawater-resistant oil seal rubber composition according to claim 8, characterized in that, The rubber composition is vulcanized to obtain a rubber molded body; the vulcanization temperature is 165~175℃; and the vulcanization time is 5~15min.

10. The application of the seawater-resistant oil seal rubber composition according to claim 8, characterized in that, The rubber molded body is used in ships, ship washing, offshore drilling platform equipment, bridge bearings, and offshore power generation equipment.

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