An epoxy resin-based shielding material and a method for preparing the same

Abstract

The application provides an epoxy resin-based shielding material and a preparation method thereof, and relates to the field of radiation-proof materials.The raw materials of the epoxy resin-based shielding material include 29-39 parts of glycidyl amine type epoxy resin, 6-8 parts of phenolic epoxy resin, 32-42 parts of aromatic amine curing agent, 5-8 parts of radiation shielding material and 15-27 parts of processing aid.The epoxy resin-based shielding material has the advantages of high-temperature resistance, heat insulation and light weight, is suitable for high-radioactivity, high-temperature and high-humidity environments, can withstand high temperatures above 190 DEG C in a medium-break loss of water accident, can effectively block and reduce heat conduction, the relative change rate of the bending strength after hygrothermal aging is less than 5%, and can guarantee the integrity of a typical shielding structure and the effectiveness of shielding and protection under the premise that the total weight is increased by no more than 4%, and is a good radiation shielding material for the nuclear island area of a nuclear power plant reactor.

Description

Technical Field

[0001] This invention relates to the field of radiation shielding materials, specifically to an epoxy resin-based shielding material and its preparation method. Background Technology

[0002] Nuclear energy, with its energy-saving, high-efficiency, and environmentally friendly characteristics, has become an inevitable choice for countries worldwide to address the energy crisis and environmental pressures. However, while releasing energy, nuclear reactions inevitably involve nuclear radiation, which is extremely harmful to humans, the environment, and equipment. Therefore, the use of nuclear energy must be based on safety. Nuclear radiation includes various charged and uncharged particles and rays, such as neutrons and gamma rays.

[0003] Nuclear power facilities typically use polyethylene (PE) shielding materials, which offer advantages such as high shielding effectiveness and light weight. However, a significant drawback is their low heat distortion temperature, with normal operating temperatures below 90°C. Generally, PE shielding materials cannot function properly in ambient temperatures above 90°C, limiting their application in higher-temperature environments. Particularly in the event of a loss-of-hydrate (LOCA) accident, the high temperatures (approximately 190°C) can cause the shielding material to soften and deform, reducing its shielding effectiveness or even causing it to fail, thus creating radiation safety hazards. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the prior art in which polyethylene-based shielding materials are prone to softening and deformation under high radioactivity, high temperature and high humidity environments, causing safety hazards, thereby providing an epoxy resin-based shielding material and its preparation method.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] In a first aspect, the present invention provides an epoxy resin-based shielding material, wherein the raw materials, by weight, comprise:

[0007] 29-39 parts of glycidyl amine type epoxy resin.

[0008] 6-8 parts of phenolic epoxy resin

[0009] 32-42 parts of aromatic amine curing agent,

[0010] 5-8 parts of radiation shielding material

[0011] Processing aids: 15-27 parts.

[0012] Furthermore, the glycidylamine type epoxy resin has an epoxy equivalent of 110-130 g / eq and a viscosity of 3000-8000 mPa·s at 50°C; the phenolic epoxy resin has an epoxy equivalent of 185-195 g / eq.

[0013] Furthermore, the aromatic amine curing agent includes diaminodiphenyl sulfone and diethyltoluenediamine, wherein the active hydrogen equivalent ratio of diaminodiphenyl sulfone to diethyltoluenediamine is 3:7.

[0014] Furthermore, the diaminodiphenyl sulfone has a water solubility of <0.1g / 100mL at 20℃ and a particle size of 60-80μm; the diethyltoluene diamine has a purity of ≥98%.

[0015] Furthermore, the radiation shielding material includes boron carbide powder, wherein the total boron content of the boron carbide powder is ≥76%, and the particle size is 60-80 μm.

[0016] Furthermore, the processing aids include at least one of toughening agents, defoamers, wetting and dispersing agents, and thixotropic agents.

[0017] Further, the processing aid comprises, by weight parts:

[0018] 10-15 parts toughening agent

[0019] Defoamer 0.08-0.1 parts,

[0020] 1-3 parts of wetting and dispersing agent

[0021] Thixotropic agent 0.3 to 1.5 parts.

[0022] Furthermore, the toughening agent is an epoxy resin with a core-shell rubber structure, having a rubber content of 40%, an epoxy equivalent of 300 g / eq, and a viscosity of 25000 mPa·s at 50°C.

[0023] Furthermore, the defoamer is an organosilicon defoamer with a density of 0.99 g / mL.

[0024] Furthermore, the thixotropic agent is an organically modified magnesium aluminum silicate compound with a density of 1.5–1.7 g / cm³. 3 .

[0025] Secondly, the present invention provides a method for preparing the epoxy resin-based shielding material, comprising the following steps:

[0026] (1) Mix all raw material components evenly to form a casting refractory;

[0027] (2) The castable material is vacuum degassed and then cast, and cured at high temperature to form a semi-finished product;

[0028] (3) The semi-finished product is mechanically processed to obtain the epoxy resin-based shielding material.

[0029] Furthermore, the high-temperature curing process is as follows: heating at 110°C for 1 hour, heating at 120°C for 1 hour, heating at 160°C for 2 hours, and heating at 200°C for 2 hours in sequence.

[0030] Further, in step (1), diaminodiphenyl sulfone is dissolved in a solvent to obtain a diaminodiphenyl sulfone solution, and glycidylamine epoxy resin, phenolic epoxy resin and diaminodiphenyl sulfone solution are mixed evenly and the solvent is removed under vacuum to form mixture 1;

[0031] Mixture 1 is mixed evenly with toughening agent, defoamer and diethyltoluenediamine to form mixture 2;

[0032] The mixture 2 is mixed evenly with the radiation shielding material to form mixture 3;

[0033] The mixture 3 is mixed evenly with the wetting and dispersing agent and the thixotropic agent to form the casting material.

[0034] Furthermore, the density of the epoxy resin-based shielding material is 1.25 ± 0.1 g / cm³. 3 .

[0035] The technical solution of this invention has the following advantages:

[0036] 1. The epoxy resin-based shielding material provided by this invention comprises the following raw materials: glycidylamine epoxy resin, phenolic epoxy resin, aromatic amine curing agent, radiation shielding material, and processing aids. To improve the heat resistance of the shielding material, a trifunctional glycidylamine epoxy resin containing a benzene ring in its structure is selected as the main matrix resin. This resin has advantages such as high activity, low viscosity, and resistance to chemical media. However, due to the presence of a large number of amino groups, this resin has strong hygroscopicity, and its resistance to environmental damp heat after curing is not stable enough. Therefore, phenolic epoxy resin, which has no hydrophilic groups in its molecular structure and good water resistance, is selected as the secondary matrix resin. The combination of the two can compensate for each other's shortcomings. Although the addition of phenolic epoxy resin can significantly improve the material's resistance to damp heat, as its content increases, the heat resistance of the shielding material decreases. Considering both the heat distortion temperature and damp heat resistance of the material, the content of phenolic epoxy resin in the matrix resin is determined (10%–20% is appropriate). Introducing heat-resistant groups and rigid structures into the system can also improve the material's heat resistance. Aromatic amine curing agents all contain stable benzene ring structures in their molecular structure, and their cured products with epoxy resins have excellent heat resistance.

[0037] 2. The epoxy resin-based shielding material provided by this invention preferably uses diaminodiphenyl sulfone and diethyltoluene diamine as compound curing agents. Diaminodiphenyl sulfone is a solid, and its viscosity increases significantly when mixed with epoxy resin. To improve the workability of the epoxy casting material, liquid diethyltoluene diamine is selected as a curing agent to adjust the system viscosity. Experimental tests show that when the active hydrogen equivalent ratio is 3:7, the material exhibits better physical and mechanical properties, heat resistance, and processability.

[0038] 3. The epoxy resin-based shielding material provided by this invention uses epoxy resin with high functionality and rigid groups and aromatic amine curing agent. Therefore, the material has a high crosslinking density and poor toughness after curing. Thus, it is preferable to add a toughening agent to modify the system. The addition of a toughening agent with a core-shell rubber structure can act as a second phase to improve its toughness without affecting the heat distortion temperature of the shielding material. Experimental verification shows that an addition amount not exceeding 30% of the epoxy resin yields the best results.

[0039] 4. The epoxy resin-based shielding material provided by the present invention preferably contains high-purity nuclear-grade boron carbide with a total boron content of ≥76%. Through thermal transfer analysis and Monte Carlo simulation calculations, it is found that when the content is in the range of 5% to 8%, the best neutron shielding effect can be achieved without significantly increasing the thermal conductivity of the composite shielding material.

[0040] 5. The epoxy resin-based shielding material provided by the present invention, through experimental comparison and epitaxial methods, further determined the optimal matrix resin ratio and curing process and parameters, so that the epoxy resin-based shielding material has a temperature resistance of over 200℃, and the quality of the molded samples is stable and reliable.

[0041] 6. The epoxy resin-based shielding material provided by this invention has the advantages of high temperature resistance, heat insulation, and lightweight. It is suitable for high-radioactivity, high-temperature, and high-humidity environments, and can withstand temperatures above 190°C under a mid-break loss-of-hydraulic accident. It effectively blocks heat and reduces heat conduction. The relative change rate of flexural strength after damp-heat aging is less than 5%. Under the premise that the total weight increase does not exceed 4%, it can ensure the integrity of the typical shielding structure and the effectiveness of shielding protection. It is an excellent radiation shielding material for the nuclear island area of ​​a nuclear power plant reactor. Application and verification at a land-based nuclear power facility have proven that it can effectively ensure the integrity and effectiveness of the overall shielding structure. Attached Figure Description

[0042] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0043] Figure 1 It is an epoxy resin-based shielding material that has been developed;

[0044] Figure 2 This is a comparison chart of the experimental group's results before and after the experiment in a simulated test of a burst water loss accident.

[0045] Figure 3 This is a comparison chart of the before and after effects of the control group in a simulated water loss accident test. Detailed Implementation

[0046] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0047] Sources of raw materials in the examples:

[0048] Glycidylamine type epoxy resin (liquid), ML-3102L, epoxy equivalent 110~130g / eq, viscosity 3000~8000mPa.s (50℃);

[0049] Phenolic epoxy resin (liquid), F-51, epoxy equivalent 185~195g / eq;

[0050] Diaminodiphenyl sulfone (solid), DDS, water solubility <0.1g / 100ml (20℃), particle size <250μm;

[0051] Diethyltoluenediamine (liquid), E-100, purity ≥98%;

[0052] Boron carbide (powder), F220, total boron content ≥76%, particle size 60~80μm;

[0053] Toughening agent (liquid), MX-154, is an epoxy resin with a core-shell rubber structure, rubber content of 40%, epoxy equivalent of approximately 300 g / eq, and viscosity of approximately 25000 mPa.s (50℃).

[0054] Defoamer (liquid), BYK-1799, silicone defoamer, has strong defoaming ability, density is about 0.99g / mL;

[0055] Wetting and dispersing agent (yellow transparent liquid), HX4010, has excellent wetting, dispersing and viscosity-reducing effects, and improves the leveling properties of products;

[0056] Thixotropic agent (grayish-white powder), GARAMITE-1958, an organically modified magnesium aluminum silicate compound, density 1.5–1.7 g / cm³. 3 Regardless of whether the viscosity is high or low, it enables the system to have excellent anti-settling and anti-sagging properties.

[0057] Where specific experimental steps or conditions are not specified in the embodiments, they can be performed according to the conventional experimental steps or conditions described in the literature in this field. All raw materials or instruments used are commercially available conventional products, including but not limited to those used in the embodiments of this application.

[0058] Example 1

[0059] An epoxy resin-based shielding material, the raw materials of which are as follows:

[0060]

[0061] The preparation method of this epoxy resin-based shielding material is as follows:

[0062] (1) Pour glycidylamine type epoxy resin, phenolic epoxy resin and diaminodiphenyl sulfone (concentration of 30g / mL) dissolved in acetone into an electric mixer, mix thoroughly at a temperature of 50-60℃ and a speed of not less than 900r / min for 40min, remove acetone solvent under vacuum to form mixture 1;

[0063] (2) Add toughening agent, defoamer and diethyltoluenediamine to mixture 1, and mix thoroughly in an electric mixer at a temperature of 50-60°C and a speed of not less than 900 r / min for 40 minutes to form mixture 2;

[0064] (3) Pour boron carbide into mixture 2 and mix thoroughly in an electric mixer at a temperature of 50-60°C and a speed of not less than 900 r / min for 50 minutes to form mixture 3;

[0065] (4) Pour the wetting and dispersing agent and the thixotropic agent into mixture 3, and mix them thoroughly in an electric mixer at a temperature of 50-60°C and a speed of not less than 900 r / min for 30 minutes to form a casting material;

[0066] (5) Pour the casting material into the mold preheated at 100℃ and heat it in the oven to cure it. The specific process is: heat at 110℃ for 1 hour → heat at 120℃ for 1 hour → heat at 160℃ for 2 hours → heat at 200℃ for 2 hours, and then cool it naturally to room temperature to form a semi-finished product.

[0067] (6) After the semi-finished product is pressed and left to stand for 1 day, it is cut and sanded into 40cm×40cm boards with a thickness of 3cm. See Figure 1 As shown.

[0068] Example 2

[0069] An epoxy resin-based shielding material, the raw materials of which are as follows:

[0070]

[0071]

[0072] The preparation method is the same as in Example 1.

[0073] Experimental Example

[0074] The epoxy resin-based shielding materials prepared in Examples 1 and 2 were subjected to performance tests. The test items, test results and test methods are shown in Table 1.

[0075] Table 1 Performance test results of epoxy resin-based shielding materials

[0076]

[0077] The test results in Table 1 show that the epoxy resin-based shielding material provided by this invention has excellent performance in all aspects.

[0078] To further verify the practical application effect of the epoxy resin-based shielding material provided by this invention, a simulation test of water loss due to breakage was conducted according to the following method:

[0079] Experimental group: lead plate (60cm×60cm, thickness 3.5cm) + epoxy resin-based shielding material prepared in Example 1 (60cm×60cm, thickness 3cm) + boron-containing polyethylene plate (60cm×60cm, thickness 7cm);

[0080] Control group: lead plate (60cm×60cm, 3.5cm thick) + boron-containing polyethylene plate (60cm×60cm, 7cm thick).

[0081] Experimental procedures and conditions: The temperature was increased according to the LOCA accident "time-temperature" curve and maintained at 190℃ for 2 hours. After the test, the appearance, dimensions, and weight of the shielding material involved in the test were inspected.

[0082] Experimental results are as follows Figures 2-3As shown in the figure, in the control group without epoxy resin-based shielding, the boron-containing polyethylene board underwent severe deformation, with a maximum unidirectional shrinkage of approximately 14.5 mm. This deformation resulted in significant radiation penetration gaps around the perimeter of the boron-containing polyethylene board. The results of the experimental group demonstrate that the epoxy resin-based shielding board prepared in Example 1 exhibits no deformation and good heat resistance. Furthermore, the deformation of the subsequent boron-containing polyethylene board is significantly reduced compared to the control group, with a maximum unidirectional shrinkage of less than 1.5 mm, thus ensuring radiation safety for personnel.

[0083] This proves that the epoxy resin-based shielding plate provided by the present invention can maintain the integrity and effectiveness of the shielding structure under the high temperature environment of 190°C in the event of water loss due to breakage. A 3cm thick epoxy resin-based shielding plate can reduce the high temperature of 190°C to below 90°C, ensuring that subsequent shielding materials such as polyethylene-based materials that are not resistant to high temperatures can be used normally.

[0084] The materials prepared in Examples 1 and 2 have been applied to a pressurized water reactor test device project, confirming that the epoxy resin-based shielding material provided by this invention can fully meet the requirements of reactor operation and engineering applications.

[0085] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. An epoxy resin-based shielding material, characterized by, The raw materials are composed of the following components by weight fraction: glycidyl amine type epoxy resin 29 parts, phenolic epoxy resin 6 parts, aromatic amine curing agent 32 parts, radiation shielding material 8 parts, processing aid 19.1 parts, the glycidyl amine type epoxy resin, ML-3102L, epoxy equivalent weight 110-130 g / eq, viscosity 3000-8000 mPa.s at 50℃; the phenolic epoxy resin, F-51, epoxy equivalent weight 185-195 g / eq; the aromatic amine curing agent includes 9.6 parts of diaminodiphenyl sulfone and 22.4 parts of diethyl toluene diamine; the diaminodiphenyl sulfone, DDS, water solubility <0.1 g / 100 mL at 20℃, particle size less than 250 μm; the diethyl toluene diamine, E-100; the equivalent ratio of active hydrogen of the diaminodiphenyl sulfone to diethyl toluene diamine is 3:7; the radiation shielding material includes boron carbide powder, the boron carbide powder, F220, total boron content ≥76%, particle size 60-80 μm; the processing aid is as follows by weight fraction: toughening agent 15 parts, antifoaming agent 0.1 part, wetting dispersant 2.5 parts, thixotropic agent 1.5 parts; the toughening agent is an epoxy resin with core-shell rubber structure, MX-154, rubber content 40%, epoxy equivalent weight 300 g / eq, viscosity 25000 mPa.s at 50℃; the antifoaming agent, BYK-1799, silicone antifoaming agent, density 0.99 g / mL; the wetting dispersant, HX4010; The thixotropic agent, GARAMITE-1958, an organically modified magnesium aluminum silicate compound, has a density of 1.5 to 1.7 g / cm 3 .

2. The method of producing an epoxy resin-based shielding material according to claim 1, characterized by, including the following steps: (1) dissolving diaminodiphenyl sulfone in acetone solvent to obtain diaminodiphenyl sulfone solution, mixing glycidyl amine type epoxy resin, phenolic epoxy resin and diaminodiphenyl sulfone solution uniformly, mixing at a temperature of 50-60℃ and a rotation speed not less than 900 r / min for 40 min, vacuum removing acetone solvent to form mixture 1; mixing the mixture 1 with toughening agent, antifoaming agent and diethyl toluene diamine uniformly, mixing at a temperature of 50-60℃ and a rotation speed not less than 900 r / min for 40 min to form mixture 2; mixing the mixture 2 with radiation shielding material uniformly, mixing at a temperature of 50-60℃ and a rotation speed not less than 900 r / min for 50 min to form mixture 3; mixing the mixture 3 with wetting dispersant and thixotropic agent uniformly, mixing at a temperature of 50-60℃ and a rotation speed not less than 900 r / min for 30 min to form casting material; (2) vacuum deaerating the casting material and then pouring, high temperature curing to form semi-finished product, the high temperature curing conditions are as follows: heating at 110℃ for 1 h, at 120℃ for 1 h, at 160℃ for 2 h and at 200℃ for 2 h; (3) mechanically processing the semi-finished product to obtain the epoxy resin based shielding material.

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