Lightweight high-temperature-resistant heat-insulation anti-irradiation nuclear protective paint, coating and preparation method and application thereof

Abstract

The invention provides a light high-temperature-resistant heat-insulation anti-irradiation nuclear protective coating, a coating as well as a preparation method and application of the coating, and relates to the technical field of nuclear protective coatings. According to the light high-temperature-resistant heat-insulating anti-irradiation nuclear protective coating, nitrogen-containing aromatic heterocyclic resin is adopted as a coating matrix, silica aerogel containing a pore-forming agent is adopted as a heat-insulating inorganic filler, in the process of preparing a coating from the coating, the coating with a specific micro-nano pore structure can be prepared through an in-situ pore-forming strategy of the pore-forming agent, and the heat-insulating property of the coating is improved. And the pore structure is effectively wrapped and shaped by resin. The coating or coating has multi-dimensional special properties such as low density, strong binding power, high temperature resistance, heat insulation, compression resistance and radiation prevention, has obvious advantages in the aspects of adhesive force, heat insulation coefficient, thermal decomposition temperature, longitudinal compression resistance and density and the like compared with the conventional nuclear protective coating, and can be used for treating the surfaces of different special-shaped parts; the great potential is realized in the field of nuclear protective coatings.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear protective coatings, and in particular to a lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coating, a coating, and a preparation method and application thereof. Background Art

[0002] Protective coatings are required for thermal insulation in high-temperature nuclear tanks, walls, some pipes, and special-shaped structures. Compared to conventional coatings, nuclear coatings must meet the same performance requirements as conventional coatings, such as adhesion, abrasion resistance, hardness, and hydrophobicity, while also meeting specialized requirements for long-term high-temperature use, excellent thermal insulation, lightweight properties, and radiation resistance.

[0003] Current nuclear power coatings are widely used in containment and radiation control area equipment, with performance focus primarily on adhesion and radiation resistance. Conventional nuclear coatings are still used on the exterior surfaces of equipment operating at high temperatures, such as high-temperature steam pipes, boiler heat exchangers, and reactor pressure vessel enclosures. Common drawbacks of conventional nuclear coatings during application and use include poor thermal stability at high temperatures and low thermal insulation performance. However, further improving heat resistance or insulation performance with conventional nuclear coatings requires a significant increase in coating thickness, which increases coating weight and compromises adhesion. Similarly, lightweight inorganic insulating materials such as rock wool and glass wool offer excellent insulation properties, but they lack adhesion and are difficult to form and process. Bends and twists during application can easily cause internal structural collapse, reducing interfacial thermal resistance and increasing thermal conductivity, particularly at stress concentration points. Therefore, developing a nuclear power coating suitable for long-term high-temperature use, offering excellent thermal insulation, lightweight, radiation resistance, and good adhesion is a current research hotspot.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The object of the present invention is to provide a lightweight, high-temperature resistant, heat-insulating, radiation-proof nuclear protective coating, coating, and preparation method and application thereof, so as to solve at least one of the above-mentioned technical problems.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The first object of the present invention is to provide a lightweight, high-temperature-resistant, heat-insulating, and radiation-resistant nuclear protective coating, comprising the following raw materials: a heat-insulating filler containing a pore-forming agent and a nitrogen-containing aromatic heterocyclic resin matrix;

[0008] Wherein, the thermal insulation filler containing pore-forming agent is made of silica aerogel and pore-forming agent;

[0009] The nitrogen-containing aromatic heterocyclic resin matrix is ​​prepared by toughening bismaleimide resin with aminophenoxyphthalonitrile and bis(phthalazinone) structural polymer;

[0010] The mass ratio of the thermal insulation filler containing the pore-forming agent to the nitrogen-containing aromatic heterocyclic resin matrix is ​​(0.3-1):1.

[0011] Furthermore, based on the above technical solution of the present invention, the pore-forming agent includes at least one of polyethylene glycol, polypropylene carbonate, polymethyl methacrylate, basic magnesium carbonate or urea, preferably includes at least one of low molecular weight polyethylene glycol, polypropylene carbonate or polymethyl methacrylate;

[0012] And / or, the pore-forming agent is a pore-forming agent with a particle size at the submicron level;

[0013] And / or, the silica aerogel is a hydrophobic silica aerogel with a particle size at the nanometer level.

[0014] Furthermore, based on the above technical solution of the present invention, in the thermal insulation filler containing the pore-forming agent, the mass ratio of the silica aerogel to the pore-forming agent is (7-10):1.

[0015] Furthermore, based on the above technical solution of the present invention, the preparation method of the thermal insulation filler containing the pore-forming agent includes the following steps:

[0016] Mechanically stirring a pore-forming agent with a submicron particle size and a hydrophobic silica aerogel with a nanometer particle size at low temperature to obtain a thermal insulation filler containing the pore-forming agent;

[0017] Preferably, the temperature of the low-temperature mechanical stirring is 0-10° C., the time of the low-temperature mechanical stirring is 4-8 h, and the speed of the low-temperature mechanical stirring is 800-2000 r / min.

[0018] Furthermore, based on the above technical solution of the present invention, in the nitrogen-containing aromatic heterocyclic resin matrix, the mass ratio of the aminophenoxyphthalonitrile to the bis(phthalazinone) structural polymer toughened bis(maleimide) resin is 1:(5-20).

[0019] Furthermore, based on the above technical solution of the present invention, the nitrogen-containing aromatic heterocyclic resin matrix is ​​prepared by ball-milling and mixing aminophenoxyphthalonitrile and bis(phthalazinone) structural polymer toughened bis(maleimide) resin.

[0020] The second object of the present invention is to provide a coating made of the lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coating provided by the first object of the present invention.

[0021] The third object of the present invention is to provide a method for preparing the above-mentioned coating, comprising the following steps:

[0022] A solid coating mixture obtained by mixing a heat-insulating filler containing a pore-forming agent and a nitrogen-containing aromatic heterocyclic resin matrix is ​​laid on the surface of the substrate, and then subjected to high-temperature hot pressing to obtain a coating;

[0023] Alternatively, a solid coating mixture obtained by mixing a heat-insulating filler containing a pore-forming agent and a nitrogen-containing aromatic heterocyclic resin matrix is ​​melted at a high temperature, and then coated on the surface of the matrix and dried to obtain a coating.

[0024] Furthermore, based on the above technical solution of the present invention, the high temperature hot pressing molding adopts a gradient temperature rise method to cure the coating, and the specific temperature rise gradient range is:

[0025] The temperature of the first gradient interval is 130-170°C (excluding 170°C) and is kept for 0.5-1h;

[0026] The temperature of the second gradient interval is 170-200°C (excluding 200°C) and is kept for 1-2 hours;

[0027] The temperature of the third gradient interval is 200-240°C (excluding 240°C), and is kept for 1-2 hours;

[0028] The temperature of the fourth gradient interval is 240-280°C (excluding 280°C), and is kept warm for 2-4 hours;

[0029] The temperature of the fifth gradient interval is 280-320° C., and the temperature is kept for 0.5-1 h.

[0030] Preferably, the pressure of the high-temperature hot pressing molding is 0.5-3 MPa, and the pressurization starts from the first gradient interval and ends at the fifth gradient interval.

[0031] The fourth purpose of the present invention is to provide the application of the above-mentioned lightweight, high-temperature resistant, heat-insulating and radiation-proof nuclear protective coating, coating or the coating prepared by the preparation method of the above-mentioned coating in the field of nuclear power equipment.

[0032] Compared with the prior art, the technical solution of the present invention has at least the following technical effects:

[0033] (1) The present invention provides a lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coating, comprising raw materials such as a heat-insulating filler containing a pore-forming agent and a nitrogen-containing aromatic heterocyclic resin matrix; wherein, by adopting the nitrogen-containing aromatic heterocyclic resin matrix, the thermal stability and high-temperature resistance of the coating are significantly improved, so that it can maintain stable performance in the harsh high-temperature environment of nuclear facilities, extend its service life, solve the core problem that existing nuclear protective coatings cannot be used stably for a long time in a high-temperature environment, and break through the high-temperature use limit; at the same time, the nitrogen-containing aromatic heterocyclic resin matrix itself gives the coating excellent radiation resistance, which enables it to effectively resist the radiation damage of high-energy particle flows and rays in nuclear facilities, maintain the structural integrity and functionality of the coating, and protect the substrate from radiation degradation.

[0034] At the same time, by filling a high proportion of silica aerogel containing pore-forming agent, an efficient thermal insulation inorganic filler, and synergistically utilizing the in-situ pore-forming strategy of the pore-forming agent in the coating formation process, a uniformly distributed micro-nano pore structure is introduced into the coating composite system, which increases the interfacial thermal resistance and greatly reduces the thermal conductivity of the coating, significantly enhancing the thermal insulation performance and lightness of the coating. In addition, combined with the precise control of high temperature and high pressure, it ensures that the newly generated pore structure is effectively wrapped and shaped by the resin, while achieving excellent thermal insulation and lightness effects, while maintaining the longitudinal compressive strength, density and interfacial bonding strength of the coating to the greatest extent, thus achieving a balance of the "multi-dimensional special properties" of the coating.

[0035] (2) The present invention also provides a coating, which is made from the above-mentioned lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coating. As an organic-inorganic hybrid coating, the coating has the characteristics of strong hydrophobicity, low density, and easy processing of organic materials, and the advantages of high-temperature resistance, heat insulation, and strong weather resistance of inorganic materials. Its characteristics are that it does not only achieve the prominence of a single function, but integrates multi-dimensional special properties such as high-temperature resistance, high-efficiency heat insulation, strong radiation resistance, low density, high adhesion, and good compressive resistance. It can effectively cope with the complex multi-field coupling (such as thermal field, radiation field, stress field, etc.) environment in nuclear facilities, provide comprehensive protection, and effectively treat the surface of complex-shaped components, indicating that it has good construction adaptability and compatibility.

[0036] (3) The present invention provides a method for preparing the above-mentioned coating, which can be prepared by a high-temperature hot pressing process or a high-temperature melt coating process. Specifically, the high-temperature hot pressing process can be precisely controlled to ensure in-situ thermal decomposition of the pore-forming agent, introduce a uniformly distributed micro-nano pore structure into the coating composite system, and the newly generated pore structure is effectively wrapped and shaped by the resin. While achieving excellent thermal insulation and lightweight effects, the longitudinal compressive strength, density and interfacial bonding of the coating are maintained to the greatest extent. This is one of the key processes for achieving a balance of the "multi-dimensional special properties" of the coating.

[0037] (4) The present invention also provides the application of lightweight, high-temperature resistant, heat-insulating, and radiation-proof nuclear protective coatings and coatings. In view of the advantages of the above-mentioned coatings and coatings, they have good application prospects in the field of nuclear power equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The drawings and the accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. Among them:

[0039] Figure 1 The data diagram of the adhesion between the coating and 304 steel provided in each embodiment and comparative example of the present invention;

[0040] Figure 2 Density data diagram of coatings provided for various embodiments and comparative examples of the present invention;

[0041] Figure 3 Thermal conductivity data diagram of coatings provided for various embodiments and comparative examples of the present invention;

[0042] Figure 4 Thermogravimetric curves of the coatings provided in various embodiments and comparative examples of the present invention;

[0043] Figure 5 A graph showing the longitudinal compressive strength data of the coatings provided in various embodiments and comparative examples of the present invention;

[0044] Figure 6 A diagram showing the preparation process of the coating and coating provided in Example 1 of the present invention;

[0045] Figure 7 This is a photograph of a circular density test sample with the coating of Example 2 of the present invention provided on its surface;

[0046] Figure 8 This is a photograph of the coating surface of a circular density test sample provided with the coating of Example 1 of the present invention after being magnified 10 times by a camera;

[0047] Figure 9 This is a photo of a square thermal conductivity test sample with the coating of Example 1 of the present invention disposed on its surface, floating on the water. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. The process parameters for which specific conditions are not specified in the following examples are generally in accordance with conventional conditions.

[0049] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to form one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed in the present invention.

[0050] According to a first aspect of the present invention, there is provided a lightweight, high-temperature-resistant, heat-insulating, and radiation-resistant nuclear protective coating, comprising the following raw materials: a heat-insulating filler containing a pore-forming agent and a nitrogen-containing aromatic heterocyclic resin matrix;

[0051] Wherein, the thermal insulation filler containing pore-forming agent is made of silica aerogel and pore-forming agent;

[0052] The nitrogen-containing aromatic heterocyclic resin matrix is ​​prepared by toughening bismaleimide resin with aminophenoxyphthalonitrile and bis(phthalazinone) structural polymer.

[0053] The mass ratio of the thermal insulation filler containing the pore-forming agent to the nitrogen-containing aromatic heterocyclic resin matrix is ​​(0.3-1):1.

[0054] The coating of the present invention significantly improves the thermal stability and high-temperature resistance of the coating by adopting a nitrogen-containing aromatic heterocyclic resin matrix, so that it can maintain stable performance and extend its service life in the harsh high-temperature environment of nuclear facilities, solving the core problem that existing nuclear protective coatings cannot be used stably for a long time in high-temperature environments, and breaking through the high-temperature usage limit; moreover, the nitrogen-containing aromatic heterocyclic resin matrix itself gives the coating excellent radiation resistance. This property enables it to effectively resist radiation damage from high-energy particle flows and rays in nuclear facilities, maintain the structural integrity and functionality of the coating, and protect the substrate from radiation degradation.

[0055] At the same time, by filling a high proportion of silica aerogel containing pore-forming agent, an efficient thermal insulation inorganic filler, and synergistically utilizing the in-situ pore-forming strategy of the pore-forming agent, a large number of uniformly distributed micro-nano pore structures (closed-pore structures) are introduced into the coating to increase the interfacial thermal resistance and significantly reduce the thermal conductivity of the coating. This not only synergizes with the aerogel to significantly enhance the thermal insulation performance and lightness of the coating, but also because the newly generated pore structure is effectively wrapped and shaped by the resin matrix, while achieving excellent thermal insulation and lightness effects, the longitudinal compressive strength, density and interfacial bonding strength of the coating are maintained to the greatest extent, thereby achieving a balance of the "multi-dimensional special properties" of the coating.

[0056] The mass ratio of the thermal insulation filler containing pore-forming agent to the nitrogen-containing aromatic heterocyclic resin matrix in the coating affects the rheological properties and viscosity of the coating in the molten state, and further affects the coating processing technology and performance, so the mass ratio of the two is limited. If the mass ratio of the thermal insulation filler containing pore-forming agent to the nitrogen-containing aromatic heterocyclic resin matrix is ​​too low (for example, lower than 0.3:1), the relative content of the resin matrix is ​​too high, which can easily cause the coating viscosity to be too low, and the thermal insulation filler content is low, which cannot meet the thermal insulation and high temperature resistance requirements of the coating, and is prone to overflow from the mold gap during the curing press (i.e., glue overflow); if the mass ratio of the thermal insulation filler containing pore-forming agent to the nitrogen-containing aromatic heterocyclic resin matrix is ​​too high (for example, higher than 1:1), the thermal insulation filler content containing pore-forming agent is too high, which can easily cause the subsequent pressurization and heating. The viscosity of the coating in the molten state is too high or even has no flow properties, resulting in large interface defects between the thermal insulation filler and the resin matrix, affecting the bonding properties and mechanical strength of the coating. In addition, after curing, concentrated pores (open-pore structure) appear inside the coating, which can easily lead to thermal seepage and thus affect the thermal insulation performance. Therefore, the typical but non-restrictive mass ratio of the thermal insulation filler containing a pore-forming agent to the nitrogen-containing aromatic heterocyclic resin matrix is ​​0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.8:1, 0.9:1 or 1.0:1.

[0057] It should be noted that the structural formula of aminophenoxyphthalonitrile in the present invention is: The amino group of the aminophenoxyphthalonitrile is substituted at the 2-, 3-, or 4-position. This substance is readily available and can be purchased commercially or prepared independently. If prepared independently, the specific synthesis steps can be referred to Chinese invention patent number CN201110367839.5, entitled "Aminophenoxyphthalonitrile Prepolymer, Cured Material, Preparation Method, and Use thereof."

[0058] The bismaleimide resin toughened by a bis(dimethylamino)benzophenone structured polymer in the present invention is a product independently developed by Dalian University of Technology. It is mainly composed of bismaleimide monomer, allyl compound, bis(dimethylamino)benzophenone structured polymer and optional other thermoplastic resin toughening agents, optional co-curing components and optional curing agents. The specific composition, dosage and preparation method are not described in detail. For details, please refer to the Chinese invention patent with patent number CN202510153791.X and the invention name "bis(dimethylamino)benzophenone structured polymer toughened bismaleimide resin and its preparation method and application".

[0059] The present invention provides a lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coating, comprising raw materials such as a heat-insulating filler containing a pore-forming agent and a nitrogen-containing aromatic heterocyclic resin matrix. As an organic-inorganic hybrid solid coating, the coating combines the strong hydrophobicity, low density, and easy processing characteristics of organic materials with the advantages of high-temperature resistance, heat insulation, and strong weather resistance of inorganic materials. It is characterized by not simply emphasizing a single function, but rather integrating multiple special properties such as high-temperature resistance, high-efficiency heat insulation, strong radiation resistance, low density, high adhesion, and good compressive strength. It can effectively cope with the complex multi-field coupling (such as thermal field, radiation field, stress field, etc.) environment in nuclear facilities, provide comprehensive protection, and effectively treat the surfaces of complex-shaped components, demonstrating its good construction adaptability and compatibility.

[0060] As an optional embodiment of the technical solution of the present invention, the pore-forming agent includes at least one of polyethylene glycol, polypropylene carbonate, polymethyl methacrylate, basic magnesium carbonate or urea, preferably includes at least one of low molecular weight polyethylene glycol, polypropylene carbonate or polymethyl methacrylate.

[0061] The pores prepared after the pore-forming agent is completely decomposed are basically micron-sized pores, so the thermal insulation, density and mechanical properties of the coating after curing are similar, and the heat resistance of the resin is not affected.

[0062] As a preferred embodiment of the technical solution of the present invention, the polyethylene glycol uses low molecular weight polyethylene glycol, and the molecular weight of the polyethylene glycol is 1000-2000, such as PEG1000, PEG1500 or PEG2000.

[0063] As an optional implementation of the technical solution of the present invention, the molecular weight of the pore-forming agent polypropylene carbonate is 50,000-100,000, such as 50,000, 75,000 or 100,000.

[0064] As an optional implementation of the technical solution of the present invention, the molecular weight of the pore-forming agent polymethyl methacrylate is 5000-20000, such as 5000, 10000, 15000 or 20000.

[0065] By further limiting the molecular weight of the pore-forming agent (such as polyethylene glycol, polypropylene carbonate, and polymethyl methacrylate), the melting temperature of the pore-forming agent (such as low-molecular-weight polyethylene glycol) during the curing of the coating is just before the coating resin matrix solidifies and gels, and the pore-forming agent is fully melted and penetrates into the coating resin earlier than the curing stage of the B-stage resin, thereby not affecting the post-curing cross-linking of the resin. At the same time, it can also play a role in regulating the viscosity during the melting stage. The construction convenience is better than the conventional coating method of introducing solvents and then volatilizing them again.

[0066] As a preferred embodiment of the technical solution of the present invention, the pore-forming agent uses a pore-forming agent with a particle size at the submicron level, for example, polyethylene glycol uses polyethylene glycol with a particle size at the submicron level.

[0067] By further limiting the particle size of the pore-forming agent (such as polyethylene glycol), the submicron pore-forming agent forms a micron-sized closed pore structure after thermal decomposition, further achieving the effect of blocking thermal convection and thermal radiation. The "micron-nanopore" synergistic insulation system obtained inside the matrix by the pore-forming agent and silica aerogel reduces thermal conductivity and further blocks heat.

[0068] As an optional implementation of the technical solution of the present invention, the silica aerogel is a hydrophobic silica aerogel with a particle size at the nanometer level.

[0069] By limiting the hydrophobicity and particle size of silica aerogel, on the one hand, the hydrophobic silica aerogel is easy to construct and not easily affected by humid environments. At the same time, the pore-forming agent has hydrophilic properties after melting, and the hydrophobic silica aerogel is not affected by the pore-forming agent and maintains its own pore structure. On the other hand, the internal structure of hydrophobic silica is loose and porous. The smaller the particle size, the more interpore interfaces of the silica aerogel created under the same volume, thereby obtaining a coating with higher porosity and enhancing thermal insulation performance.

[0070] As an optional embodiment of the technical solution of the present invention, in the thermal insulation filler containing a pore-forming agent, the mass ratio of silica aerogel to pore-forming agent is (7-10):1. The mass ratio of silica aerogel to pore-forming agent mainly affects the thermal insulation and longitudinal compressive properties of the coating. If the mass ratio of silica aerogel to pore-forming agent is too high (for example, greater than 10:1), it is easy to cause the coating viscosity to be too high, making it difficult to fully disperse the silica aerogel, causing it to easily agglomerate in the resin, affecting the mechanical properties and adhesion after subsequent curing. At the same time, the micron-scale pores produced by the pore-forming agent are too few, affecting the thermal insulation performance. If the mass ratio of silica aerogel to pore-forming agent is too low (for example, less than 6:1), it is easy to cause the content of silica aerogel providing nano-scale pores to be too low, which is insufficient to support the thermal insulation performance of the coating. Therefore, typical but non-limiting mass ratios of silica aerogel to pore-forming agent are 7:1, 7.5:1, 8:1, 8.5:1, 9:1, 9.5:1 or 10:1, etc.

[0071] As an optional embodiment of the technical solution of the present invention, a method for preparing a thermal insulation filler containing a pore-forming agent comprises the following steps:

[0072] A pore-forming agent with a particle size of submicron level and a silicon dioxide aerogel with a particle size of nanometer level are mechanically stirred at low temperature to obtain a heat-insulating filler containing the pore-forming agent.

[0073] Mechanically stirring the pore former and the silica aerogel thermal insulation filler at low temperature can avoid premature softening of the pore former and agglomeration between the pore former particles, which would affect the dispersion characteristics of the submicron pore former.

[0074] As an optional implementation scheme of the technical solution of the present invention, the temperature of low-temperature mechanical stirring is 0-10°C (for example, 0°C, 2°C, 5°C, 8°C or 10°C, etc.), the time of low-temperature mechanical stirring is 4-8h (for example, 4h, 5h, 6h, 7h or 8h, etc.), and the rotation speed is 800-2000r / min (for example, 800r / min, 1000r / min, 1200r / min, 1500r / min or 2000r / min, etc.).

[0075] By further limiting the process parameters of the low-temperature mechanical stirring process, the submicron pore-forming agent and the nano-scale silica aerogel are evenly distributed without aggregation.

[0076] As an optional implementation of the technical solution of the present invention, the nitrogen-containing aromatic heterocyclic resin matrix is ​​prepared by ball milling and mixing aminophenoxyphthalonitrile and bis(phthalazinone) structural polymer toughened bis(maleic) resin; wherein the ball milling speed is 300-600 r / min (for example, 300 r / min, 400 r / min, 500 r / min or 600 r / min, etc.).

[0077] As an optional implementation of the technical solution of the present invention, the mass ratio of aminophenoxyphthalonitrile to the toughened bismaleimide resin of the phthalazinone structure polymer is 1:(5-20).

[0078] The present invention utilizes two different substances, aminophenoxyphthalonitrile and a bis(phthalazinone) structural polymer toughened bis(maleimide) resin, to form a nitrogen-containing aromatic heterocyclic resin matrix. If either aminophenoxyphthalonitrile or bis(phthalazinone) structural polymer is used alone to toughen the bis(maleimide) resin, crosslinking during subsequent high-temperature hot pressing to form a coating fails to yield a coating with excellent mechanical strength, resulting in excessive softness or brittleness, respectively. Therefore, a composite of the two enhances matrix toughness. Typical, but non-limiting, weight ratios of aminophenoxyphthalonitrile to bis(phthalazinone) structural polymer toughened bis(maleimide) resin are 1:5, 1:6, 1:8, 1:10, 1:12, 1:15, 1:18, or 1:20, among others.

[0079] According to a second aspect of the present invention, there is also provided a coating, which is made of the lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coating provided by the first aspect of the present invention.

[0080] In view of the advantages of the lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coating provided by the present invention, the same advantages are also possessed after it is prepared into a coating, which will not be described in detail here.

[0081] According to a third aspect of the present invention, there is also provided a method for preparing the above-mentioned coating, comprising the following steps:

[0082] A solid coating mixture obtained by mixing a heat-insulating filler containing a pore-forming agent and a nitrogen-containing aromatic heterocyclic resin matrix is ​​spread on the surface of the substrate, and then subjected to high-temperature hot pressing to obtain a coating;

[0083] Alternatively, a solid coating mixture obtained by mixing a heat-insulating filler containing a pore-forming agent and a nitrogen-containing aromatic heterocyclic resin matrix is ​​melted at a high temperature, and then coated on the surface of the matrix and dried to obtain a coating.

[0084] It should be noted that the present invention can adopt different coating preparation methods to prepare the coating, preferably using a high-temperature hot pressing molding process.

[0085] During the high-temperature hot pressing process, the aminophenoxyphthalonitrile and the diazolinone structural polymer toughened bismaleimide resin, which serve as the nitrogen-containing aromatic heterocyclic resin matrix, will undergo cross-linking and curing, so that the active amino group in the diazolinone structural polymer toughened bismaleimide resin attacks the nitrile group in the aminophenoxyphthalonitrile, and is cyclized into a triazine ring or phthalocyanine structure through an imine intermediate, forming a three-dimensional aromatic heterocyclic network containing a rigid diazolinone biphenyl skeleton.

[0086] The core role of the pore-forming agent in the high-temperature hot pressing molding process is to introduce a uniformly distributed micro-nano pore structure into the coating composite system through in-situ thermal decomposition; this not only cooperates with the aerogel to significantly enhance the thermal insulation performance and lightness of the coating, but also combines with the precise control of high temperature and high pressure to ensure that the newly generated pore structure is effectively wrapped and shaped by the resin, while achieving excellent thermal insulation and lightness effects, while maintaining the longitudinal compressive strength, density and interfacial bonding of the coating to the greatest extent. This is the key process innovation point for achieving a balance of the "multi-dimensional special properties" of the coating.

[0087] The coating provided by the present invention can be a single-layer coating or a multi-layer coating. The multi-layer coating can be obtained by subjecting the lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coating of the present invention to multiple high-temperature hot pressing processes or coating processes, or can be a lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coating of the present invention as a primer and another coating composition as a topcoat, or another coating composition as a primer and a lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coating of the present invention as a topcoat.

[0088] The coating provided by the present invention not only has excellent radiation resistance, thermal stability and high temperature resistance, but also has good thermal insulation, lightweight effect, and certain longitudinal compressive strength, density and interface bonding strength.

[0089] It should be noted that the “substrate” mentioned in the coating preparation method may refer to a planar substrate or a non-planar substrate, such as the surface of a substrate of a complex-shaped irregular component.

[0090] As an optional implementation of the technical solution of the present invention, high-temperature hot pressing molding adopts a gradient temperature increase to cure the coating, and the specific temperature increase gradient range is:

[0091] The temperature of the first gradient interval is 130-170° C. but not including 170° C. (e.g., 130° C., 140° C., 150° C., 160° C., or 168° C.), and is kept for 0.5-1 h (e.g., 0.5 h, 0.75 h, or 1 h);

[0092] The temperature of the second gradient interval is 170-200° C. but does not include 200° C. (e.g., 175° C., 180° C., 185° C., 190° C., 195° C., or 198° C.), and is kept for 1-2 hours (e.g., 1 hour, 1.5 hours, or 2 hours);

[0093] The temperature of the third gradient interval is 200-240° C. but does not include 240° C. (e.g., 205° C., 210° C., 220° C., 230° C., or 238° C.), and is kept for 1-2 hours (e.g., 1 hour, 1.5 hours, or 2 hours);

[0094] The temperature of the fourth gradient interval is 240-280° C. but does not include 280° C. (for example, 240° C., 250° C., 260° C., 270° C., or 278° C.), and is kept for 2-4 hours (for example, 2 hours, 3 hours, or 4 hours);

[0095] The temperature of the fifth gradient interval is 280-320° C. (for example, 280° C., 290° C., 300° C., 310° C., or 320° C.), and the temperature is kept for 0.5-1 h (for example, 0.5 h, 0.75 h, or 1 h).

[0096] By further limiting the temperature and time of each of the above gradient intervals, the first temperature rising gradient completes the melting of the resin and the softening of the pore-forming agent; the second temperature rising gradient completes the gel state transition of the resin and the melting of the pore-forming agent; the third temperature rising gradient completes the curing of the resin and the decomposition of the pore-forming agent; the fourth temperature rising gradient post-cures the resin and completely decomposes the pore-forming agent; and the fifth temperature rising stage completes the complete sintering of the thermal decomposition products of the pore-forming agent.

[0097] As an optional implementation of the technical solution of the present invention, the pressure of high-temperature hot pressing molding is 0.5-3MPa (0.5MPa, 1MPa, 1.5MPa, 2MPa, 2.5MPa or 3MPa, etc.), where the upper pressure point starts in the first gradient interval and ends when the coating solidifies in the fifth gradient interval.

[0098] According to a fourth aspect of the present invention, there is also provided an application of a lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective paint and coating.

[0099] In view of the advantages of the above-mentioned paints and coatings, they have good application prospects in the field of nuclear power equipment.

[0100] The present invention will be further described in detail below with reference to specific examples and comparative examples. The raw materials used in the following examples and comparative examples are as follows: the silica aerogel block is hydrophobic and has a thermal conductivity of 0.09–0.013 W·m -1 K -1 , porosity>80%, aqueous contact angle>120°, purchased from Hunan Ronglan Intelligent Technology Co., Ltd.; hydrophobic silica powder, particle size 50-200nm, purchased from Beijing Huawei Ruike Chemical Technology Co., Ltd., CAS: 68611-44-9; the structural formula of aminophenoxyphthalonitrile is Among them, the amino group is substituted at the 2-position; the bis(phthalazinone) structured polymer toughened bis(maleic acid) resin is a bis(phthalazinone) structured polymer (diphenyl sulfone bis(phthalazinone) structured copolymerized biphenyl diphenol type polyaryl ether sulfone, PSUBPS) toughened bis(maleic acid) resin, and its constituent raw materials, dosage and preparation method can be found in the Chinese invention patent specification (Example 6) with patent number CN202510153791.X and invention name "Bis(phthalazinone) structured polymer toughened bis(maleic acid) resin and its preparation method and application".

[0101] Example 1

[0102] This embodiment provides a lightweight, high-temperature-resistant, heat-insulating, and radiation-resistant nuclear protective coating, comprising the following raw materials: a heat-insulating filler containing a pore-forming agent and a nitrogen-containing aromatic heterocyclic resin matrix;

[0103] The thermal insulation filler containing a pore-forming agent is made of hydrophobic silica aerogel with a particle size at the nanometer level and a pore-forming agent PEG-1000, and the mass ratio of the hydrophobic silica aerogel to the pore-forming agent PEG-1000 is 8:1.

[0104] The nitrogen-containing aromatic heterocyclic resin matrix comprises aminophenoxyphthalonitrile and bis(phthalazinone) structural polymer toughened bis(maleimide) resin, and the mass ratio of aminophenoxyphthalonitrile to bis(phthalazinone) structural polymer toughened bis(maleimide) resin is 1:5.

[0105] The mass ratio of the thermal insulation filler containing the pore-forming agent to the nitrogen-containing aromatic heterocyclic resin matrix is ​​2:3.

[0106] This embodiment also provides a method for preparing the above-mentioned lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coating and coating. The preparation process is shown in FIG. Figure 6As shown in the figure (which summarizes the preparation process of the thermal insulation filler containing a pore-forming agent, the preparation process of the nitrogen-containing aromatic heterocyclic resin matrix, and the high-temperature hot pressing molding process of the coating (coating)), the specific steps are as follows:

[0107] Step 1: 5 g of silica aerogel block was subjected to high-speed shear crushing at room temperature, with the speed controlled at 3000 r / min, and crushing for 2 min to obtain nano-scale hydrophobic silica aerogel powder (particle size of 50-200 nm);

[0108] Step 2: Pre-freeze 2 g of pore-forming agent polyethylene glycol (PEG-1000) in a -18°C refrigerator;

[0109] Step 3: Place the frozen PEG-1000 in a low-temperature grinder, control the temperature at -10°C, adjust the speed to 2000 r / min, and grind for 1 minute to obtain submicron PEG-1000 powder (particle size 150-500 nm);

[0110] Step 4: mechanically stirring the nano-scale hydrophobic silica aerogel powder prepared in step 1 and the submicron-scale PEG-1000 prepared in step 3 at a mass ratio of 8:1 at low temperature, controlling the temperature at 5° C. and the rotation speed at 1500 r / min for 4 hours to obtain a silica aerogel thermal insulation filler containing a pore-forming agent;

[0111] Step 5: ball milling the aminophenoxyphthalonitrile and the bis(phthalazinone) structural polymer toughened bis(maleimide) resin at a mass ratio of 1:5 at 100° C. and a speed of 400 r / min for 6 h, collecting and grinding after cooling to obtain a nitrogen-containing aromatic heterocyclic resin matrix;

[0112] Step 6: The silica aerogel thermal insulation filler containing a pore-forming agent in step 4 and the nitrogen-containing aromatic heterocyclic resin matrix in step 5 are mixed and stirred in a mass ratio of 2:3 for 6 hours at a speed of 800 r / min to obtain a coating mixture (a lightweight, high-temperature resistant, heat-insulating, and radiation-resistant nuclear protective coating);

[0113] Step seven, lay the coating mixture on the surface of the 304 steel special-shaped part with a laying thickness of 8 mm. After fixing it with a mold, place it in an electric hot press for high-temperature hot pressing. Specifically, keep it warm at 160°C in the first gradient interval for 0.5h, and start pressurizing as soon as the temperature of the first gradient interval is reached (until the end of the fifth gradient interval), the pressurization pressure is 1.2MPa, keep it warm at 180°C for 2h in the second gradient interval, keep it warm at 200°C for 2h in the third gradient interval, keep it warm at 240°C for 2h in the fourth gradient interval, and keep it warm at 280°C for 0.5h in the fifth gradient interval. After cooling and demolding, a coating formed by a lightweight, high-temperature resistant, heat-insulating, and radiation-proof nuclear protective coating is obtained.

[0114] Example 2

[0115] This embodiment provides a lightweight, high-temperature-resistant, heat-insulating, and radiation-resistant nuclear protective coating, comprising the following raw materials: a heat-insulating filler containing a pore-forming agent and a nitrogen-containing aromatic heterocyclic resin matrix;

[0116] The thermal insulation filler containing a pore-forming agent is made of hydrophobic silica aerogel with a particle size at the nanometer level and a pore-forming agent polypropylene carbonate (PPC, molecular weight of 50,000). The mass ratio of the hydrophobic silica aerogel to the pore-forming agent polypropylene carbonate is 10:1.

[0117] The nitrogen-containing aromatic heterocyclic resin matrix comprises aminophenoxyphthalonitrile and bis(phthalazinone) structural polymer toughened bis(maleimide) resin, and the mass ratio of aminophenoxyphthalonitrile to bis(phthalazinone) structural polymer toughened bis(maleimide) resin is 2:7.

[0118] The mass ratio of the thermal insulation filler containing the pore-forming agent to the nitrogen-containing aromatic heterocyclic resin matrix is ​​1:1.

[0119] This embodiment also provides a method for preparing the above-mentioned lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coating and coating, which is specifically carried out according to the following steps:

[0120] Step 1: 8 g of silica aerogel block was subjected to high-speed shear crushing at room temperature, with the speed controlled at 2700 r / min, and crushing for 4 min to obtain nano-scale hydrophobic silica aerogel powder (particle size of 50-200 nm);

[0121] Step 2: Pre-freeze 5 g of polypropylene carbonate (molecular weight 50,000) in a -10°C refrigerator;

[0122] Step 3: Place the frozen polypropylene carbonate in a low-temperature grinder, control the temperature at -5°C, adjust the speed to 1500 r / min, and grind for 2 minutes to obtain polypropylene carbonate powder with a submicron particle size (particle size of 150-500 nm);

[0123] Step 4: mechanically stirring the nano-scale hydrophobic silica aerogel powder prepared in step 1 and the submicron-scale polypropylene carbonate prepared in step 3 at a mass ratio of 10:1 at low temperature, controlling the temperature at 0°C and the rotation speed at 1000 r / min for 3 hours to obtain a silica aerogel thermal insulation filler containing a pore-forming agent;

[0124] Step 5: ball milling the aminophenoxyphthalonitrile and the bis(phthalazinone) structural polymer toughened bis(maleimide) resin at a mass ratio of 2:7 at 120° C. and a speed of 300 r / min for 4 h, collecting and crushing after cooling to obtain a nitrogen-containing aromatic heterocyclic resin matrix;

[0125] Step 6: The silica aerogel thermal insulation filler containing a pore-forming agent in step 4 and the nitrogen-containing aromatic heterocyclic resin matrix in step 5 are mixed and stirred in a mass ratio of 1:1 for 4 hours at a speed of 500 r / min to obtain a coating mixture (a lightweight, high-temperature resistant, heat-insulating, and radiation-resistant nuclear protective coating);

[0126] Step seven, lay the coating mixture on the surface of the 304 steel special-shaped part with a laying thickness of 5 mm. After fixing it with a mold, place it in an electric hot press for high-temperature hot pressing. Specifically, keep it warm at 140°C for 1 hour in the first gradient interval, and start pressurizing as soon as the temperature of the first gradient interval is reached (until the end of the fifth gradient interval), the pressurization pressure is 0.9 MPa, keep it warm at 200°C for 1 hour in the second gradient interval, keep it warm at 240°C for 1 hour in the third gradient interval, keep it warm at 280°C for 3 hours in the fourth gradient interval, and keep it warm at 300°C for 0.5 hours in the fifth gradient interval. After cooling and demolding, a coating formed by a lightweight, high-temperature resistant, heat-insulating, and radiation-proof nuclear protective coating is obtained.

[0127] Example 3

[0128] This embodiment provides a lightweight, high-temperature-resistant, heat-insulating, and radiation-resistant nuclear protective coating, comprising the following raw materials: a heat-insulating filler containing a pore-forming agent and a nitrogen-containing aromatic heterocyclic resin matrix;

[0129] The thermal insulation filler containing a pore-forming agent is made of hydrophobic silica aerogel with a particle size at the nanometer level and a pore-forming agent, polymethyl methacrylate (PMMA, molecular weight 6000), with a mass ratio of hydrophobic silica aerogel to pore-forming agent, polymethyl methacrylate, being 7:1.

[0130] The nitrogen-containing aromatic heterocyclic resin matrix comprises aminophenoxyphthalonitrile and bis(phthalazinone) structural polymer toughened bis(maleimide) resin, and the mass ratio of aminophenoxyphthalonitrile to bis(phthalazinone) structural polymer toughened bis(maleimide) resin is 1:9.

[0131] The mass ratio of the thermal insulation filler containing the pore-forming agent to the nitrogen-containing aromatic heterocyclic resin matrix is ​​1:3.

[0132] This embodiment also provides a method for preparing the above-mentioned lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coating, which is specifically carried out according to the following steps:

[0133] Step 1: 4 g of silica aerogel was subjected to high-speed shear crushing at room temperature, with the speed controlled at 4000 r / min, and crushing for 1 min to obtain nano-scale hydrophobic silica aerogel powder (particle size of 50-200 nm);

[0134] Step 2: Pre-freeze 3 g of polymethyl methacrylate (molecular weight 6000) in a -7°C refrigerator;

[0135] Step 3: Place the frozen polymethyl methacrylate in a low-temperature crusher, control the temperature at 0°C, adjust the speed to 3000 r / min, and crush for 2 minutes to obtain polymethyl methacrylate powder with a submicron particle size (particle size of 150-500 nm);

[0136] Step 4: mechanically stirring the nano-scale hydrophobic silica aerogel powder prepared in step 1 and the submicron-scale polymethyl methacrylate prepared in step 3 at a mass ratio of 7:1 at low temperature, controlling the temperature at 3°C ​​and the rotation speed at 800 r / min for 5 hours to obtain a silica aerogel thermal insulation filler containing a pore-forming agent;

[0137] Step 5: ball milling the aminophenoxyphthalonitrile and the bis(phthalazinone) structural polymer toughened bis(maleimide) resin at a mass ratio of 1:9 at 110° C. and a speed of 500 r / min for 5 hours, collecting and crushing after cooling to obtain a nitrogen-containing aromatic heterocyclic resin matrix;

[0138] Step 6: The silica aerogel thermal insulation filler containing a pore-forming agent in step 4 and the nitrogen-containing aromatic heterocyclic resin matrix in step 5 are mixed and stirred at a mass ratio of 1:3 for 5 hours at a speed of 700 r / min to obtain a coating mixture (a lightweight, high-temperature resistant, heat-insulating, and radiation-resistant nuclear protective coating);

[0139] Step seven, lay the coating mixture on the surface of the 304 steel special-shaped part with a laying thickness of 10 mm. After fixing it with a mold, place it in an electric hot press for high-temperature hot pressing. Specifically, keep it warm at 140°C for 0.5h in the first gradient interval, and start pressurizing as soon as the temperature of the first gradient interval is reached (until the end of the fifth gradient interval), the pressurization pressure is 2MPa, keep it warm at 170°C for 2h in the second gradient interval, keep it warm at 210°C for 1h in the third gradient interval, keep it warm at 250°C for 4h in the fourth gradient interval, and keep it warm at 290°C for 1h in the fifth gradient interval. After cooling and demolding, a coating formed by a lightweight, high-temperature resistant, heat-insulating, and radiation-proof nuclear protective coating is obtained.

[0140] Example 4

[0141] This embodiment provides a lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coating. The composition is the same as in Example 1, except that the mass ratio of the heat-insulating filler containing a pore-forming agent to the nitrogen-containing aromatic heterocyclic resin matrix in Example 1 is adjusted from 2:3 to 1:3.

[0142] The preparation method of the radiation-proof nuclear protective coating of this embodiment is the same as that of Example 1, except that in step 6, the silica aerogel thermal insulation filler containing a pore-forming agent and the nitrogen-containing aromatic heterocyclic resin matrix are mixed in a mass ratio of 1:3. The remaining steps and process parameters are the same as those of Example 1.

[0143] Example 5

[0144] This embodiment provides a lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coating. The composition is the same as in Example 1, except that the mass ratio of the heat-insulating filler containing a pore-forming agent to the nitrogen-containing aromatic heterocyclic resin matrix in Example 1 is adjusted from 2:3 to 3:3.

[0145] The preparation method of the radiation-proof nuclear protective coating of this embodiment is the same as that of Example 1, except that in step 6, the silica aerogel thermal insulation filler containing a pore-forming agent and the nitrogen-containing aromatic heterocyclic resin matrix are mixed in a mass ratio of 3:3. The remaining steps and process parameters are the same as those of Example 1.

[0146] Example 6

[0147] This embodiment provides a lightweight, high-temperature resistant, heat-insulating, and radiation-proof nuclear protective coating. In addition to keeping the total amount of the thermal insulation filler containing a pore-forming agent in the coating of Example 1 unchanged, the mass ratio of silica aerogel and the pore-forming agent in the thermal insulation filler containing a pore-forming agent is adjusted from 8:1 to 10:1. The rest of the composition is the same as that of Example 1.

[0148] The method for preparing the radiation-resistant nuclear protective coating of this embodiment is the same as that of Example 1, except that the mass ratio of the nano-scale silica aerogel powder and the submicron-scale pore-forming agent PEG-1000 in step 4 is adjusted from 8:1 to 10:1. The remaining steps and process parameters are the same as those of Example 1.

[0149] Comparative Example 1

[0150] This comparative example provides a lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coating. The composition is the same as that of Example 1 except that no pore-forming agent is added to the heat-insulating filler of Example 1.

[0151] The preparation method of the radiation-proof nuclear protective coating in this comparative example is the same as that in Example 1, except that steps 2 and 3 are not performed, and in step 4, only the nano-scale hydrophobic silica aerogel powder in step 1 is subjected to low-temperature mechanical stirring.

[0152] Comparative Example 2

[0153] This comparative example provides a lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coating. Except that the hydrophobic silica aerogel in the thermal insulation filler of Example 1 is replaced with an equal amount of hydrophobic silica powder, the rest of the composition and dosage are the same as those of Example 1.

[0154] The preparation method of the radiation-proof nuclear protective coating in this comparative example is the same as that in Example 1, except that step 1 is not performed and the nano-scale hydrophobic silica aerogel powder is replaced with hydrophobic silica powder (50-200 nm) in step 4.

[0155] Comparative Example 3

[0156] This comparative example provides a lightweight, high-temperature resistant, heat-insulating, and radiation-resistant nuclear protective coating, except that the bis(phthalazinone) structural polymer toughened bismaleimide resin in the nitrogen-containing heteroaromatic resin matrix of Example 1 is replaced by an equal amount of aminophenoxyphthalonitrile, that is, the nitrogen-containing heteroaromatic resin matrix only includes aminophenoxyphthalonitrile, and the total amount of the nitrogen-containing heteroaromatic resin matrix is ​​the same as the total amount of the nitrogen-containing heteroaromatic resin matrix in Example 1, and the rest of the composition is the same as that of Example 1.

[0157] The preparation method of the radiation-proof nuclear protective coating in this comparative example is the same as that in Example 1, except that in step 5, the bismaleimide resin toughened by the phthalazinone structure polymer is replaced with an equal amount of aminophenoxyphthalonitrile, that is, the bismaleimide resin toughened by the phthalazinone structure polymer is not added, and only the aminophenoxyphthalonitrile is ball-milled. The remaining steps and process parameters are the same as those in Example 1.

[0158] Comparative Example 4

[0159] This comparative example provides a lightweight, high-temperature resistant, heat-insulating, and radiation-resistant nuclear protective coating, except that the aminophenoxyphthalonitrile in the nitrogen-containing aromatic heterocyclic resin matrix of Example 1 is replaced by an equal amount of a diazolinone structured polymer toughened bismaleimide resin, that is, the nitrogen-containing aromatic heterocyclic resin matrix only includes a diazolinone structured polymer toughened bismaleimide resin, and the total amount of the nitrogen-containing aromatic heterocyclic resin matrix remains unchanged from Example 1, and the rest of the composition is the same as Example 1.

[0160] The preparation method of the radiation-proof nuclear protective coating in this comparative example is the same as that in Example 1, except that in step 5, aminophenoxyphthalonitrile is replaced by an equal amount of a bis(phthalazinone) structured polymer toughened bis(maleic acid) resin. That is, no aminophenoxyphthalonitrile is added, and only the bis(phthalazinone) structured polymer toughened bis(maleic acid) resin is ball-milled. The remaining steps and process parameters are the same as those in Example 1.

[0161] Comparative Example 5

[0162] This comparative example provides a lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coating. The composition is the same as in Example 1, except that the mass ratio of the heat-insulating filler containing a pore-forming agent to the nitrogen-containing aromatic heterocyclic resin matrix in Example 1 is adjusted from 2:3 to 3:2.

[0163] The preparation method of the radiation-proof nuclear protective coating in this comparative example is the same as that in Example 1, except that the silica aerogel insulating filler containing a pore-forming agent and the nitrogen-containing aromatic heterocyclic resin matrix are mixed in a mass ratio of 3:2 in step 6. The remaining steps and process parameters are the same as those in Example 1.

[0164] Comparative Example 6

[0165] The preparation method of the protective coating for anti-radiation nuclear power plant in this comparative example is as follows, except that the gradient temperature increase strategy is not implemented in step seven. Instead, the coating mixture is directly laid on the surface of the 304 steel special-shaped part with a laying thickness of 8 mm. After being fixed with a mold, it is placed in an electric hot press and directly heated to 260°C. Pressurization is started before heating, and the pressurization pressure is 1.2 MPa. The heat and pressure are maintained for 7 hours. After cooling and demolding, a coating formed by a lightweight, high-temperature resistant, heat-insulating, and anti-radiation nuclear protective coating is obtained.

[0166] In order to further verify the technical effects of the above embodiments and comparative examples, the following experimental examples are specially set up.

[0167] Experimental Example 1

[0168] (1) The adhesion of the coating formed by the lightweight high-temperature resistant heat-insulating and radiation-proof nuclear protective coating provided in each embodiment and comparative example to the 304 steel special-shaped parts was tested. The specific testing method was based on GB / T5210-2006. The specific results are shown in Tables 1 and Figure 1 shown.

[0169] (2) The density of the lightweight, high-temperature-resistant, heat-insulating, and radiation-resistant nuclear protective coatings provided in each embodiment and comparative example was tested. The test method was based on GB / T 6750-2007. The specific results are shown in Tables 1 and Figure 2 shown.

[0170] (3) The thermal conductivity of the lightweight, high-temperature-resistant, heat-insulating, and radiation-resistant nuclear protective coatings provided in each embodiment and comparative example was tested. The testing method was based on GB / T 10294-2008. The specific results are shown in Tables 1 and Figure 3 As shown;

[0171] (4) The lightweight, high-temperature-resistant, heat-insulating, and radiation-resistant nuclear protective coatings provided in each embodiment and comparative example were subjected to thermogravimetric testing. The initial thermal decomposition temperature obtained is shown in Table 1, and the thermogravimetric curve is shown in Figure 4 shown.

[0172] (5) The mechanical impact properties (longitudinal compressive strength) of the lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coatings provided in each embodiment and comparative example were tested. The testing method was based on GB / T 1732-2020. The specific results are shown in Tables 1 and Figure 5 shown.

[0173] (6) The gamma-ray cumulative integral measurement of the lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coatings provided in each embodiment and comparative example was tested. The testing method was based on GB / T 24100-2009. The specific results are shown in Table 1.

[0174] The various special performance indicators of the lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coatings of the embodiments and comparative examples are summarized in Table 1:

[0175] Table 1

[0176]

[0177]

[0178] From Table 1 and Figure 1 It can be seen that the bonding strength between the lightweight, high-temperature resistant, heat-insulating, and radiation-proof nuclear protective coatings prepared in Examples 1-6 and 304 steel is greater than 0.57 MPa, which is due to the specific raw material composition of the present invention and the high-temperature hot pressing process adopted.

[0179] From Table 1 and Figure 2 It can be seen that the density of the lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coatings prepared in Examples 1-6 is lower than 0.66 g / cm 3 Since the crushed nano-scale pore-forming agent (such as PEG-1000) is completely decomposed into CO2 during the high-temperature curing process, submicron-scale pores are formed inside the coating. For details, please refer to Figure 7 and Figure 8 . Figure 7 This is a photo of a circular density test sample prepared using the coating (coating) of Example 2. Figure 8 The surface of the circular sample coating obtained by using the coating (coating) of Example 1 is magnified 10 times by a camera. Figure 8 The pore structure in the coating can be clearly observed. The existence of the pore structure in the coating structure can reduce the density of the coating. For details, please refer to Figure 9 . Figure 9 A photograph shows a square sample with a cured coating of the present invention (the sample is a square thermal conductivity test sample made using the paint (coating) of Example 1) floating on the water surface, which also proves that the coating provided by the present invention has the characteristics of low density and light weight.

[0180] From Table 1 and Figure 3 It can be seen that the thermal conductivity of the lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coatings prepared in Examples 1-6 is lower than 0.06 W·m -1 K -1 This performance reduction is achieved through the synergistic effect of silica aerogel and pore-forming agent. On the one hand, the introduction of thermal insulating silica aerogel reduces the thermal conductivity of the coating. On the other hand, the pore-forming agent releases a large amount of CO2 during the high-temperature curing process, which can form a hollow closed-pore structure inside the coating. The introduction of gas will greatly inhibit the transfer rate of heat flow inside the coating and increase the interfacial thermal resistance inside the coating.

[0181] From Table 1 and Figure 4It can be seen that the initial decomposition temperatures of the lightweight, high-temperature, heat-insulating, and radiation-resistant nuclear protective coatings prepared in Examples 1-6 are all higher than 400°C. Silica aerogel is a high-temperature resistant inorganic filler that can withstand temperatures above 1000°C. In addition, the intrinsic thermal decomposition temperature of the synthesized nitrogen-containing aromatic heterocyclic resin matrix is ​​higher than 450°C, which fully meets the special service conditions for long-term use at 400°C.

[0182] From Table 1 and Figure 5 It can be seen that the mechanical impact strength (longitudinal compressive strength) of the lightweight, high-temperature resistant, heat-insulating, and radiation-proof nuclear protective coating prepared in Examples 1-6 is higher than 1 MPa. Compared with conventional water-based coatings, it has excellent longitudinal compressive resistance, thanks to the dual effects of high-temperature hot pressing molding process and pore-forming agent. Since the pore-forming agent releases CO2 during thermal decomposition in the resin b-stage curing zone, a loaded high-pressure area is spontaneously formed inside the coating while the press is pressing, thereby increasing the longitudinal compressive resistance of the coating (coating).

[0183] Examples 4 and 5 serve as control experiments for Example 1, primarily examining the effects of varying the mass ratio of the thermal insulation filler containing a pore-forming agent to the nitrogen-containing heteroaromatic resin matrix on coating performance. As shown in Table 1, in Example 4, decreasing the content of the aerogel filler containing a pore-forming agent improves adhesion and mechanical properties, while decreasing thermal insulation and increasing density. In Example 5, increasing the content of the aerogel filler containing a pore-forming agent decreases adhesion and mechanical properties, while increasing thermal insulation and decreasing density.

[0184] Example 6 is a control experiment for Example 1, primarily examining the effect of the mass ratio of silica aerogel to pore-forming agent in the pore-forming thermal insulation filler on coating performance. As shown in Table 1, the moderate increase in silica aerogel content in Example 6 increases the amount of nanopores introduced into the matrix, but reduces the amount of micron-sized gas released by the pore-forming agent during the curing phase, which in turn reduces the internal load pressure of the coating and, consequently, the coating density. Furthermore, the addition of silica aerogel creates interfacial thermal resistance with the cross-linked coating, resulting in a slight decrease in thermal conductivity. While adhesion remains at the same strength level as in Example 1, the longitudinal impact strength of the coating is reduced.

[0185] Comparative Examples 1-6 are all comparative experiments with Example 1. Specifically, compared with Example 1, the thermal insulation filler in the radiation-resistant nuclear protective coating of Comparative Example 1 does not contain a pore-forming agent. As can be seen from the data in Table 1, the absence of a pore-forming agent significantly increases the density and thermal conductivity of the coating. Furthermore, the absence of a pore-forming agent component is equivalent to the absence of micron-sized pores. The coating is equivalent to being hot-pressed into a compacted "plate"-like structure, increasing its longitudinal compressive strength. Furthermore, the pore-forming agent regulates the viscosity of the coating at the melting temperature, affecting its adhesion. Therefore, the adhesion in Comparative Example 1 is also poor. Furthermore, the excessive viscosity results in interfacial defects within the coating, limiting the formation of the cross-linked network and, in turn, affecting the initial thermal decomposition temperature of the coating.

[0186] Compared with Example 1, Comparative Example 2 replaces the hydrophobic silica aerogel in the thermal insulation filler with an equal amount of hydrophobic silica powder. As can be seen from the data in Table 1, due to the replacement of the hydrophobic silica aerogel with light density and excellent thermal insulation performance with hydrophobic silica powder, the reduction of the nano-mesoporous structure inside the coating greatly affects the density and thermal conductivity of the coating. At the same time, the interface density of the hydrophobic silica powder is slightly larger, and the interface defects between the hydrophobic silica powder and the nitrogen-containing aromatic heterocyclic resin matrix are significantly poorly dispersed, resulting in agglomeration, inhibiting resin cross-linking, and thus affecting the initial decomposition temperature and longitudinal compressive strength.

[0187] Compared to Example 1, Comparative Examples 3 and 4 used only one of the substances (bis(phthalazinone)-structured polymer-toughened bismaleimide resin or aminophenoxyphthalonitrile) as the nitrogen-containing aromatic heterocyclic resin matrix. As shown in Table 1, compared with a mixture of the two, using only one of the substances as the coating matrix significantly reduced the crosslinking structure of the resin, rendering it overly brittle, leading to reduced coating adhesion, initial thermal degradation temperature, and longitudinal compressive strength. Due to insufficient crosslinking, the internal micro- and nano-pores of the resin were unable to withstand the original compressive strength of Example 1 during curing, leading to structural collapse within the coating, resulting in "pore compaction" and increased density. Furthermore, insufficient crosslinking prevented effective dispersion of the silica aerogel powder, increasing thermal conductivity.

[0188] Comparative Example 5, compared to Example 1, adjusts the mass ratio of the thermal insulation filler containing a pore-forming agent to the nitrogen-containing aromatic heterocyclic resin matrix. As shown in Table 1, high additions of the pore-forming agent and silica aerogel significantly increase the introduction of micro- and nano-mesopores, leading to a significant decrease in thermal conductivity and density. However, the large amount of pore-forming agent introduced ultimately degrades the microstructured pores, transforming them into large stress concentration defects. This leads to insufficient adhesion of the resin to the 304 steel plate during curing, thus affecting the coating's adhesion, initial thermal degradation temperature, and longitudinal compressive strength.

[0189] Comparative Example 6 employed a different temperature increase strategy than Example 1. As can be seen from the data in Table 1, since Comparative Example 6 did not undergo a post-curing stage and the curing rate was too fast during the initial curing stage, insufficient crosslinking resulted. This inadequate reaction within the resin resulted in significant curing defects, which reduced the coating's adhesion, initial thermal decomposition temperature, and longitudinal compressive strength. Furthermore, the pore-forming agent was not effectively melted, skipping directly to the thermal degradation step. This prevented the melted pore-forming agent from regulating the coating's viscosity, leading to curing defects that increased density and thermal conductivity.

[0190] It can be seen that compared with Examples 1-6, the performance of the coatings or coatings of Comparative Examples 1-6 all have different defects, which also confirms that the content of the pore-forming agent, the silica aerogel thermal insulation filler, the aminophenoxyphthalonitrile and the diazonaphthalene structural polymer toughened bismaleimide resin in the nitrogen-containing aromatic heterocyclic resin matrix, the ratio between the filler and the resin, and the heating gradient all affect the comprehensive performance of the lightweight, high-temperature resistant, thermally insulating, and radiation-proof nuclear protective coating.

[0191] From the above, it can be seen that the present invention, as a functional coating under multi-field coupling, has a low density (<0.6g / cm 3 ), strong bonding strength (>0.57MPa), high temperature resistance (long-term use above 400℃), heat insulation (thermal conductivity <0.06W·m -1 K -1 ), radiation protection (when the fast neutron dose is 1×10 14 n / cm 2 , γ-ray cumulative dose <1×10 7 Gy) and other multi-dimensional special properties, which have obvious advantages over conventional nuclear protective coatings. It can be processed on the surfaces of different special parts and has great potential in the field of nuclear protective coatings.

[0192] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A lightweight, high-temperature-resistant, heat-insulating, radiation-proof nuclear protective coating, characterized in that: The method comprises the following raw materials: a heat-insulating filler containing a pore-forming agent and a nitrogen-containing aromatic heterocyclic resin matrix; Wherein, the thermal insulation filler containing pore-forming agent is made of silica aerogel and pore-forming agent; The nitrogen-containing aromatic heterocyclic resin matrix is ​​prepared by toughening bismaleimide resin with aminophenoxyphthalonitrile and bis(phthalazinone) structural polymer; The mass ratio of the thermal insulation filler containing the pore-forming agent to the nitrogen-containing aromatic heterocyclic resin matrix is ​​(0.3-1):

1.

2. The lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coating according to claim 1, characterized in that: The pore-forming agent comprises at least one of polyethylene glycol, polypropylene carbonate, polymethyl methacrylate, basic magnesium carbonate or urea, preferably comprises at least one of low molecular weight polyethylene glycol, polypropylene carbonate or polymethyl methacrylate; And / or, the pore-forming agent is a pore-forming agent with a particle size at the submicron level; And / or, the silica aerogel is a hydrophobic silica aerogel with a particle size at the nanometer level.

3. The lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coating according to claim 1 or 2, characterized in that: In the thermal insulation filler containing a pore-forming agent, the mass ratio of the silica aerogel to the pore-forming agent is (7-10):

1.

4. The lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coating according to claim 3, characterized in that: The preparation method of the thermal insulation filler containing a pore-forming agent comprises the following steps: Mechanically stirring a pore-forming agent with a submicron particle size and a hydrophobic silica aerogel with a nanometer particle size at low temperature to obtain a thermal insulation filler containing the pore-forming agent; Preferably, the temperature of the low-temperature mechanical stirring is 0-10° C., the time of the low-temperature mechanical stirring is 4-8 h, and the speed of the low-temperature mechanical stirring is 800-2000 r / min.

5. The lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coating according to claim 1, characterized in that: In the nitrogen-containing aromatic heterocyclic resin matrix, the mass ratio of the aminophenoxyphthalonitrile to the toughened bismaleimide resin with a phthalazinone structure polymer is 1:(5-20).

6. The lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coating according to claim 1, characterized in that: The nitrogen-containing aromatic heterocyclic resin matrix is ​​prepared by ball-milling and mixing aminophenoxy phthalonitrile and a bis(phthalazinone) structural polymer toughened bis(malonium) resin.

7. A coating, characterized in that The lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coating is made of the coating according to any one of claims 1 to 6.

8. The method for preparing the coating according to claim 7, characterized in that: The following steps are involved: A solid coating mixture obtained by mixing a heat-insulating filler containing a pore-forming agent and a nitrogen-containing aromatic heterocyclic resin matrix is ​​laid on the surface of the substrate, and then subjected to high-temperature hot pressing to obtain a coating; Alternatively, a solid coating mixture obtained by mixing a heat-insulating filler containing a pore-forming agent and a nitrogen-containing aromatic heterocyclic resin matrix is ​​melted at a high temperature, and then coated on the surface of the matrix and dried to obtain a coating.

9. The method for preparing the coating according to claim 8, characterized in that: The high temperature hot pressing molding adopts a gradient temperature rise method to cure the coating, and the specific temperature rise gradient range is: The temperature of the first gradient interval is 130-170°C (excluding 170°C) and is kept for 0.5-1h; The temperature of the second gradient interval is 170-200°C (excluding 200°C) and is kept for 1-2 hours; The temperature of the third gradient interval is 200-240°C (excluding 240°C), and is kept for 1-2 hours; The temperature of the fourth gradient interval is 240-280°C (excluding 280°C), and is kept warm for 2-4 hours; The temperature of the fifth gradient interval is 280-320° C., and the temperature is kept for 0.5-1 h. Preferably, the pressure of the high-temperature hot pressing molding is 0.5-3 MPa, and the pressurization starts from the first gradient interval and ends at the fifth gradient interval.

10. Use of the lightweight, high-temperature-resistant, heat-insulating, and radiation-proof nuclear protective coating according to any one of claims 1 to 6, the coating according to claim 7, or the coating prepared by the preparation method according to claim 8 or 9 in the field of nuclear power equipment.

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