A high-temperature resistant and radiation resistant thread sealant and a preparation method thereof

Abstract

The application provides an anti-radiation high-temperature-resistant threaded sealant and a preparation method thereof. The sealant comprises the following components in parts by mass: base oil: 30-60 parts, long-chain macromolecular alkane: 5-30 parts, solid lubricant: 20-60 parts, adhesive: 0.01-0.5 parts, dispersant: 0.01-1 part, filler: 1-5 parts, antioxidant: 0.01-0.5 part, and the use temperature of the sealant is -29-635 DEG C, the anti-radiation performance to gamma rays is >=1.5*10 7 Gy irradiation dose, and the sealant is applied to the sealing of small-diameter, tight-tolerance threaded fasteners under the conditions of nuclear radiation and high temperature and high pressure (635 DEG C and 16 MPa), and has good lubricity and is easy to disassemble.

Description

Technical Field

[0001] This invention relates to a radiation-resistant and high-temperature resistant thread sealant, belonging to the field of adhesive technology, specifically a radiation-resistant and high-temperature resistant thread sealant and its preparation method. Background Technology

[0002] Nuclear power plants contain numerous bolts and structural components that are constantly exposed to high temperatures, high radiation, and vibration during operation. Some equipment also comes into contact with liquid media. Traditional materials like rubber, asbestos, and metal gaskets can age or corrode, leading to loosening and failure of these bolts and components. To ensure effective fixing of bolts, fasteners, and connectors during operation, and to allow for easy disassembly and assembly during subsequent maintenance, thread sealant is typically used to fill the minute gaps between the bolt threads and the fixed object, achieving both fixation and sealing.

[0003] Currently, conventional thread sealants on the market have poor sealing performance and are prone to failure at high temperatures, failing to meet the requirements of the high-temperature and high-radiation environment of nuclear power plants. Furthermore, conventional thread sealants are prone to denaturation under high-temperature or high-radiation conditions, causing threaded fasteners to jam and making them difficult to disassemble, repair, and assemble. Summary of the Invention

[0004] To address the shortcomings of the existing technology, this invention proposes a radiation-resistant and high-temperature resistant thread sealant and its preparation method. The thread sealant provided by this invention can achieve tight contact between bolts and structural components, with good sealing performance, good durability, and easy disassembly. It can be used for sealing internal and external threaded fasteners, pipe joints, and threaded plugs in nuclear islands, and has a good sealing effect.

[0005] The radiation-resistant and high-temperature resistant thread sealant provided by this invention has an operating temperature range of -29 to 635°C and a radiation resistance to gamma rays of ≥1.5×10⁻⁶. 7 Gy irradiation dose.

[0006] This invention utilizes a combination of graphite and / or boron nitride particles of varying sizes. Different particle shapes exhibit different frictional directions and coefficients. Through a gradation design of the particle sizes, the invention achieves both fixing and sealing. Simultaneously, the lubricating properties of the base oil and graphite itself form a continuous protective film on the threads and treated areas, preventing surface scratches, corrosion, and jamming, thus facilitating equipment disassembly. Furthermore, research on the combination of graphite and boron nitride particle sizes and their proportions with the base oil can improve the sealant's high-temperature resistance and high-radiation resistance.

[0007] The first aspect of this invention provides a radiation-resistant and high-temperature-resistant thread sealant, which comprises the following components in parts by weight:

[0008] Base oil: 30-60 parts

[0009] High molecular weight alkanes: 5-25 parts

[0010] Solid lubricant: 20-60 parts

[0011] Filler: 1-5 parts

[0012] Adhesive: 0.01-0.5 parts

[0013] Dispersant: 0.01-1 part,

[0014] Antioxidant: 0.01-0.5 parts.

[0015] Furthermore, the base oil is an aromatic base oil, preferably one or more of alkylnaphthalene, polyphenylene ether, heavy alkylbenzene, and alkyl biphenyl; aromatic base oils have stable chemical properties and excellent hydrolytic stability and thermal oxidation stability. Using aromatic base oils can improve the radiation resistance of thread sealants; furthermore, the mass fraction of the base oil is preferably 30-60 parts, and more preferably 40-50 parts.

[0016] Furthermore, the high molecular weight alkane is at least one of paraffin wax, ceresin wax, petrolatum, and microcrystalline wax. The high molecular weight alkane has low chemical activity, stable chemical properties, certain strength, and good plasticity, which can maintain the stability of the product system. Furthermore, the amount of high molecular weight alkane used is 5-25 parts, more preferably 15-25 parts; the molecular weight of the wax is below 1000, and the wax is preferably paraffin wax with a molecular weight of 500-1000. The high molecular weight alkane can improve the sintering resistance of the sealant to a certain extent.

[0017] Furthermore, the solid lubricant is at least one of graphite and boron nitride, more preferably graphite and boron nitride. These two materials are among the most heat-resistant and chemically resistant materials. Their effective combination can improve high-temperature resistance, sealing performance, and radiation resistance. The graphite particle size is 10-300 μm; the boron nitride particle size is 5-100 μm; preferably, the graphite particle size is 50-300 μm and the boron nitride particle size is 5-50 μm; more preferably, the graphite particle size is 60-200 μm and the boron nitride particle size is 5-30 μm.

[0018] Further, the ratio of graphite to boron nitride content is 3-10:1, preferably 5-8:1; further, the particle size ratio of graphite to boron nitride is 2-12:1, preferably 4-8:1. Studies have found that by optimizing the particle size distribution and dosage of the lubricant, high-temperature resistance and radiation resistance can be effectively improved, and seizing and jamming phenomena can be effectively prevented.

[0019] Furthermore, the filler is at least one of glass fiber particles, diatomaceous earth, and silica. The particle size of the filler is 10-150 μm, more preferably 20-120 μm, and even more preferably 50-100 μm. The filler can adjust the viscosity of the sealant. The particle size distribution of the filler and the lubricant can improve the sealing performance, high temperature resistance, and radiation resistance.

[0020] Furthermore, the aforementioned adhesive is one of methyl methacrylate, ethyl methacrylate, and propylene oxide, used to enhance the adhesion between the product and the component.

[0021] Furthermore, the dispersant mentioned above is polyacrylate or polyvinylamide, which helps the product form a stable system;

[0022] Furthermore, the antioxidant mentioned above is one of 2,6-di-tert-butyl-p-cresol, tert-butylhydroquinone, and phenolic resin, which improves the antioxidant stability of the product and enhances its storage stability.

[0023] Another aspect of the present invention provides a method for preparing a radiation-resistant and high-temperature resistant thread sealant, the method comprising the following steps:

[0024] 1. Place the base oil and antioxidant of the formula into a reaction vessel and heat to 80-100℃ while stirring;

[0025] 2. Heat the high molecular weight alkane until it is completely melted, then add it to the mixture obtained in step 1) and stir until it is evenly dispersed;

[0026] 3. Add solid lubricant and filler to the mixture obtained in step 2), continue stirring, and keep the system temperature at 80-100℃. After stirring evenly, cool, grind, and filter to obtain the radiation-resistant and high-temperature resistant sealant material.

[0027] Furthermore, the stirring speed in steps 1) and 2) above shall not be less than 800 rpm, and the stirring speed in step 3) may be appropriately reduced, preferably to 400 rpm.

[0028] Another aspect of the present invention provides the use of a radiation-resistant and high-temperature resistant thread sealant, which is used for sealing threads, bolts or other fasteners in the high-temperature and high-radiation environment of nuclear power plants.

[0029] The effective effects of this invention are as follows:

[0030] The radiation-resistant and high-temperature resistant thread sealant provided by this invention can achieve tight contact between bolts and structural components, with good sealing performance, good durability, and easy disassembly; it can be used for sealing internal and external threaded fasteners, pipe joints, and threaded plugs in nuclear islands, and has a good sealing effect.

[0031] The radiation-resistant and high-temperature resistant thread sealant provided by this invention has an operating temperature range of -29 to 635°C and a radiation resistance to gamma rays of ≥1.5×10⁻⁶. 7 Gy irradiation dose.

[0032] This invention utilizes a combination of graphite and / or boron nitride particles of varying sizes. Different particle shapes exhibit different frictional directions and coefficients. Through particle size gradation design, a fixing and sealing effect can be achieved. By adjusting the amounts of base oil and solid lubricant, a continuous protective film can be formed on the threads and treated areas, preventing surface scratches, corrosion, and jamming, thus facilitating equipment disassembly. Furthermore, research on the combination of graphite and boron nitride particle sizes and their proportions with base oil can improve the sealant's high-temperature resistance, high-radiation resistance, and corrosion resistance.

[0033] The sealant provided by this invention has good chemical stability, excellent resistance to media, and can resist corrosion from almost all organic and inorganic fluids, exhibiting excellent chemical corrosion resistance.

[0034] The sealant of this invention has few impurity elements, which can effectively prevent chemical corrosion and stress corrosion. The content levels of harmful elements such as halogen elements, heavy metal elements, and sulfur in the product meet the requirements of nuclear power. Detailed Implementation

[0035] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] This invention provides a radiation-resistant and high-temperature resistant thread sealant, which comprises the following components in parts by weight: base oil: 30-60 parts, high molecular weight alkane: 5-25 parts, solid lubricant: 20-60 parts, filler: 1-5 parts, adhesive: 0.01-0.5 parts, dispersant: 0.01-1 parts, and antioxidant: 0.01-0.5 parts.

[0037] Furthermore, the base oil is an aromatic base oil, preferably one or more of alkylnaphthalene, polyphenylene ether, heavy alkylbenzene, and alkyl biphenyl; further, the mass fraction of the base oil is preferably 30-60 parts, and more preferably 40-50 parts.

[0038] Furthermore, the high molecular weight alkane is at least one of paraffin wax, ceresin wax, petrolatum, and microcrystalline wax; further, the amount of high molecular weight alkane used is 5-25 parts, more preferably 15-25 parts; the molecular weight of the wax is below 1000, and the wax is preferably paraffin wax with a molecular weight of 500-1000.

[0039] Furthermore, the solid lubricant is at least one of graphite and boron nitride, more preferably graphite and boron nitride, wherein the graphite particle size is 10-300 μm; the boron nitride particle size is 5-100 μm; preferably, the graphite particle size is 50-300 μm and the boron nitride particle size is 5-50 μm; more preferably, the graphite particle size is 60-200 μm and the boron nitride particle size is 5-30 μm.

[0040] The ratio of graphite to boron nitride is further 3-10:1, preferably 5-8:1; and the particle size ratio of graphite to boron nitride is further 2-12:1, preferably 4-8:1.

[0041] Furthermore, the filler is at least one of glass fiber particles, diatomaceous earth, and silica, and the size of the filler particles is 10-150 μm, more preferably 20-120 μm, and even more preferably 50-100 μm.

[0042] Another aspect of the present invention provides a method for preparing a radiation-resistant and high-temperature resistant thread sealant, the method comprising the following steps:

[0043] 1. Place the base oil and antioxidant of the formula into a reaction vessel and heat to 80-100℃ while stirring;

[0044] 2. Heat the high molecular weight alkane until it is completely melted, then add it to the mixture obtained in step 1) and stir until it is evenly dispersed;

[0045] 3. Add solid lubricant and filler to the mixture obtained in step 2), continue stirring, and keep the system temperature at 80-100℃. After stirring evenly, cool, grind, and filter to obtain the radiation-resistant and high-temperature resistant sealant material.

[0046] Furthermore, the stirring speed in steps 1) and 2) above shall not be less than 800 rpm, and the stirring speed in step 3) may be appropriately reduced, preferably to 400 rpm.

[0047] The following are specific examples:

[0048] Example 1

[0049] This embodiment discloses a radiation-resistant and high-temperature-resistant thread sealant and its preparation method, which includes the following preparation process:

[0050] (1) Add 400g of polyphenylene ether and 1g of antioxidant to the reactor, start stirring and keep it at 1000rpm, and slowly heat it to 80℃;

[0051] (2) Heat 200g of paraffin wax until it is completely melted, add it to the reactor, keep the temperature of the reactor at 80℃, and keep the stirring speed at 1000rpm;

[0052] (3) Add 5g of adhesive and 5g of dispersant to the reactor and stir until homogeneous. Add 30g of diatomaceous earth and 220g of graphite powder to the reactor. Increase the stirring speed to 1500rpm and maintain the temperature at 80℃ until the mixture in the reactor is homogeneous, then stop stirring. The graphite powder has a particle size of 100μm.

[0053] (4) While the product in the reactor is still hot, transfer it to the mixing tank, let it cool naturally, and then grind and filter it to make a radiation-resistant and high-temperature resistant thread sealant.

[0054] Example 2

[0055] This embodiment discloses a radiation-resistant and high-temperature-resistant thread sealant and its preparation method, which includes the following preparation process:

[0056] (1) Add 350g of heavy alkylbenzene and 1g of antioxidant to the reactor, start stirring and keep it at 1000rpm, and slowly heat it to 80℃;

[0057] (2) Heat 250g of petroleum jelly until it is completely melted, add it to the reactor, keep the temperature of the reactor at 80℃, and keep the stirring speed at 1000rpm;

[0058] (3) Add 5g of adhesive and 5g of dispersant to the reactor and stir evenly. Add 20g of diatomaceous earth, 10g of glass fiber particles, 200g of graphite powder and 20g of boron nitride to the reactor. Increase the stirring speed to 1500rpm and keep the temperature at 80℃. Stop stirring after the mixture in the reactor is evenly mixed. The particle size of boron nitride particles is 30μm and the particle size of graphite powder is 100μm.

[0059] (4) While the product in the reactor is still hot, transfer it to the mixing tank, let it cool naturally, and then grind and filter it to make a radiation-resistant and high-temperature resistant thread sealant.

[0060] Example 3

[0061] This embodiment discloses a radiation-resistant and high-temperature-resistant thread sealant and its preparation method, which includes the following preparation process:

[0062] (1) Add 400g of alkyl biphenyl and 1g of antioxidant to the reactor, start stirring and keep it at 1000rpm, and slowly heat it to 80℃;

[0063] (2) Heat 200g of ceresin until it is completely melted, add it to the reactor, keep the temperature of the reactor at 80℃, and keep the stirring speed at 1000rpm;

[0064] (3) Add 5g of adhesive and 5g of dispersant to the reactor and stir evenly. Add 20g of diatomaceous earth, 10g of glass fiber particles and 220g of graphite powder to the reactor. Increase the stirring speed to 1200rpm and keep the temperature at 100℃. Stop stirring after the mixture in the reactor is evenly mixed. The particle size of the graphite powder is 100μm.

[0065] (4) While the product in the reactor is still hot, transfer it to the mixing tank, let it cool naturally, and then grind and filter it to make a radiation-resistant and high-temperature resistant thread sealant.

[0066] Example 4

[0067] This embodiment discloses a radiation-resistant and high-temperature-resistant thread sealant and its preparation method, which includes the following preparation process:

[0068] (1) Add 300g of alkylnaphthalene and 1g of antioxidant to the reactor, start stirring and keep it at 1000rpm, and slowly heat it to 80℃;

[0069] (2) Heat 250g of paraffin wax until it is completely melted, add it to the reactor, keep the temperature of the reactor at 80℃, and keep the stirring speed at 1000rpm;

[0070] (3) Add 5g of adhesive and 5g of dispersant to the reactor and stir evenly. Add 30g of silica, 20g of boron nitride and 200g of graphite powder to the reactor. Increase the stirring speed to 1200rpm and keep the temperature at 100℃. Stop stirring after the mixture in the reactor is evenly mixed. The particle size of the boron nitride particles is 30μm and the particle size of the graphite powder is 100μm.

[0071] (4) While the product in the reactor is still hot, transfer it to the mixing tank, let it cool naturally, and then grind and filter it to make a radiation-resistant and high-temperature resistant thread sealant.

[0072] Example 5

[0073] This embodiment discloses a radiation-resistant and high-temperature-resistant thread sealant and its preparation method, which includes the following preparation process:

[0074] (1) Add 350g of heavy alkylbenzene and 1g of antioxidant to the reactor, start stirring and keep it at 1000rpm, and slowly heat it to 80℃;

[0075] (2) Heat 250g of petroleum jelly until it is completely melted, add it to the reactor, keep the temperature of the reactor at 80℃, and keep the stirring speed at 1000rpm;

[0076] (3) Add 5g of adhesive and 5g of dispersant to the reactor and stir evenly. Add 20g of diatomaceous earth, 10g of glass fiber particles, 185g of graphite powder and 35g of boron nitride to the reactor. Increase the stirring speed to 1500rpm and keep the temperature at 80℃. Stop stirring after the mixture in the reactor is evenly mixed. The particle size of boron nitride particles is 30μm and the particle size of graphite powder is 100μm.

[0077] (4) While the product in the reactor is still hot, transfer it to the mixing tank, let it cool naturally, and then grind and filter it to make a radiation-resistant and high-temperature resistant thread sealant.

[0078] Example 6

[0079] This embodiment discloses a radiation-resistant and high-temperature-resistant thread sealant and its preparation method, which includes the following preparation process:

[0080] (1) Add 350g of heavy alkylbenzene and 1g of antioxidant to the reactor, start stirring and keep it at 1000rpm, and slowly heat it to 80℃;

[0081] (2) Heat 250g of petroleum jelly until it is completely melted, add it to the reactor, keep the temperature of the reactor at 80℃, and keep the stirring speed at 1000rpm;

[0082] (3) Add 5g of adhesive and 5g of dispersant to the reactor and stir evenly. Add 20g of diatomaceous earth, 10g of glass fiber particles, 195g of graphite powder and 25g of boron nitride to the reactor. Increase the stirring speed to 1500rpm and keep the temperature at 80℃. Stop stirring after the mixture in the reactor is evenly mixed. The particle size of boron nitride particles is 30μm and the particle size of graphite powder is 100μm.

[0083] (4) While the product in the reactor is still hot, transfer it to the mixing tank, let it cool naturally, and then grind and filter it to make a radiation-resistant and high-temperature resistant thread sealant.

[0084] Example 7

[0085] This embodiment discloses a radiation-resistant and high-temperature-resistant thread sealant and its preparation method, which includes the following preparation process:

[0086] (1) Add 350g of heavy alkylbenzene and 1g of antioxidant to the reactor, start stirring and keep it at 1000rpm, and slowly heat it to 80℃;

[0087] (2) Heat 250g of petroleum jelly until it is completely melted, add it to the reactor, keep the temperature of the reactor at 80℃, and keep the stirring speed at 1000rpm;

[0088] (3) Add 5g of adhesive and 5g of dispersant to the reactor and stir evenly. Add 20g of diatomaceous earth, 10g of glass fiber particles, 200g of graphite powder and 20g of boron nitride to the reactor. Increase the stirring speed to 1500rpm and keep the temperature at 80℃. Stop stirring after the mixture in the reactor is evenly mixed. The particle size of boron nitride particles is 10μm and the particle size of graphite powder is 60μm.

[0089] (4) While the product in the reactor is still hot, transfer it to the mixing tank, let it cool naturally, and then grind and filter it to make a radiation-resistant and high-temperature resistant thread sealant.

[0090] Example 8

[0091] This embodiment discloses a radiation-resistant and high-temperature-resistant thread sealant and its preparation method, which includes the following preparation process:

[0092] (1) Add 350g of heavy alkylbenzene and 1g of antioxidant to the reactor, start stirring and keep it at 1000rpm, and slowly heat it to 80℃;

[0093] (2) Heat 250g of petroleum jelly until it is completely melted, add it to the reactor, keep the temperature of the reactor at 80℃, and keep the stirring speed at 1000rpm;

[0094] (3) Add 5g of adhesive and 5g of dispersant to the reactor and stir evenly. Add 20g of diatomaceous earth, 10g of glass fiber particles, 210g of graphite powder and 10g of boron nitride to the reactor. Increase the stirring speed to 1500rpm and keep the temperature at 80℃. Stop stirring after the mixture in the reactor is evenly mixed. The particle size of boron nitride particles is 30μm and the particle size of graphite powder is 100μm.

[0095] (4) While the product in the reactor is still hot, transfer it to the mixing tank, let it cool naturally, and then grind and filter it to make a radiation-resistant and high-temperature resistant thread sealant.

[0096] The main properties of the sealants prepared in Examples 1-8 above are listed in Table 1.

[0097] Table 1. Sealant Performance

[0098]

[0099]

[0100] To better demonstrate the performance of the sealant material prepared in the embodiments of the present invention, the present invention selects the products obtained in Examples 1-4 above at a concentration of 0.01-0.1 g / dm³. 3 The coating was evenly applied to the threaded portion of the 304 stainless steel bolts. After tightening the fasteners with a force of 30-50 N·m using a wrench, a portion of them were placed in a sintering furnace and heated to 635℃ in an air atmosphere for 500 hours. After naturally cooling to room temperature, they were disassembled. The results are shown in Table 2, indicating that the sealant designed in this invention has excellent high-temperature resistance.

[0101] To test the radiation resistance of the sealant, the gamma-ray irradiation performance was tested using Part 3 of the Specification for Protective Coatings for Pressurized Water Reactor Nuclear Power Plant Facilities and Equipment: Test Methods for the Effect of Gamma-ray Irradiation on Coating Systems. The test performance data are shown in Table 2.

[0102] Table 2 lists the high-temperature resistance and radiation resistance of the sealant materials in Examples 1-8.

[0103]

[0104] As can be seen from the above embodiments and test results, the radiation-resistant and high-temperature resistant thread sealant provided by the present invention can achieve tight contact between bolts and structural components, with good sealing performance, good durability, and easy disassembly; it can be used for sealing internal and external threaded fasteners, pipe joints and threaded plugs in nuclear islands, and has a good sealing effect.

[0105] The radiation-resistant and high-temperature resistant thread sealant provided by this invention has an operating temperature range of -29 to 635°C and a radiation resistance to gamma rays of ≥1.5×10⁻⁶. 7 The Gy irradiation dose also effectively solves the technical problem of meshing of detachable connectors under high temperature and long-term irradiation conditions, which helps to extend service life and improve equipment performance.

[0106] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made according to the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention. It should be understood that although the present invention has been described by way of example according to its preferred embodiments, it should not be limited to the above embodiments. For those skilled in the art, the present invention can have various modifications and variations.

Claims

1. A high temperature and radiation resistant thread sealant, characterized in that, The sealant comprises the following components by mass fraction: The base oil is one or more of alkyl naphthalene, polyphenyl ether, heavy alkyl benzene, and alkyl biphenyl.

2. The anti-radiation, high-temperature threaded seal of claim 1, wherein, The base oil is 40-50 parts by mass.

3. The radiation resistant, high temperature thread sealant of claim 1, wherein, The amount of the high molecular weight alkane is 15-25 parts.

4. A radiation resistant, high temperature thread sealant according to any one of claims 1 to 3, characterised in that, The graphite particle size is 50-300 μm, and the boron nitride particle size is 5-50 μm.

5. A radiation resistant, high temperature thread sealant according to any one of claims 1 to 3, characterised in that, The graphite particle size is 60-200 μm, and the boron nitride particle size is 5-30 μm.

6. A high-temperature radiation resistant thread sealant as claimed in any one of claims 1 to 3, characterised in that, The mass content ratio of graphite to boron nitride is 5-8:1, and the particle size ratio of graphite to boron nitride is 4-8:

1.

7. A radiation resistant, high temperature thread sealant according to any one of claims 1 to 3, wherein the sealant comprises: The filler is at least one of glass fiber particles, diatomite, and white carbon black, and the filler particle size is 10-150 μm.

8. A method of producing the anti-radiation high-temperature-resistant thread sealant according to any one of claims 1 to 7, characterized by, The preparation method comprises the following steps: (1) Put the base oil and the antioxidant in a reaction container, and stir to heat to 80-100°C; (2) Heat the high molecular weight alkane to complete melting, and then add to the mixture obtained in step (1), and stir to disperse uniformly; (3) Add the solid lubricant and the filler to the mixture obtained in step (2), continue to stir, and keep the system temperature at 80-100°C, and then cool, grind, and filter to obtain the anti-radiation high-temperature-resistant thread sealant.

9. The production process according to claim 8, characterized in that The stirring speed in all the above preparation steps is not less than 800 rpm, and the stirring speed in step 3) is higher than that in steps 1) and 2). The stirring speed in all the above preparation steps is not less than 800 rpm, and the stirring speed in step 3) is higher than that in steps 1) and 2).

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