Gamma ray resistant silicone rubber composite, method of making gamma ray resistant article

Abstract

The application provides a gamma ray-proof silicone rubber composite material, which is composed of a plurality of rubber layer units, the rubber layer units comprise rubber layer A and rubber layer B arranged alternately, and the rubber layer B is arranged at the inner layer of the composite material; the rubber layer A is prepared from methyl vinyl phenyl silicone rubber, modified shielding agent, vulcanizing agent and fumed silica; the rubber layer B is prepared from methyl vinyl phenyl silicone rubber, lead, fumed silica and vulcanizing agent; and the modified shielding agent is prepared from metal oxide and silane coupling agent. The application also provides a preparation method of the gamma ray-proof silicone rubber composite material and a gamma ray-proof product. The composite material provided by the application has the advantages of radiation resistance, the multi-layer structure effectively makes up for the weak absorption area, improves the dispersion uniformity of the heterogeneous filler, and the modified shielding agent further improves the shielding performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite materials, in particular to a gamma-ray-proof silicone rubber composite material, a preparation method thereof and a gamma-ray-proof product. BACKGROUND

[0002] The high-end protective equipment launched by the American RST company uses rubber as a base material and rare metals and their compounds as functional fillers, has good ray shielding performance and no biological toxicity, but is expensive and the technology is blocked to the outside. In China, lead rubber radiation protection materials are still the main ones, which are composite materials using lead and its compounds as the main filling materials. Because of the relatively simple processing, mature technology, good ray protection performance and certain price advantage, they account for a large proportion in the shielding material market.

[0003] However, with the improvement of safety awareness, people gradually realize the shortcomings of lead-containing protective equipment. On the one hand, single lead shielding material has a weak absorption zone; on the other hand, direct contact with lead has biological toxicity. Therefore, it is urgent to develop a shielding material that avoids direct contact with lead and can make up for the weak absorption zone of lead as the main material of the ray protection equipment. SUMMARY

[0004] The technical problem solved by the present application is to provide a gamma-ray-proof silicone rubber composite material. The silicone rubber composite material provided by the present application can not only avoid direct contact with lead, but also make up for the defect of reduced shielding rate caused by the weak absorption zone of lead.

[0005] Therefore, the present application provides a gamma-ray-proof silicone rubber composite material, which is composed of a plurality of rubber layer units, the rubber layer units include alternately arranged rubber layer A and rubber layer B, and the rubber layer B is arranged in the inner layer of the composite material.

[0006] The rubber layer A is prepared from methyl vinyl phenyl silicone rubber, modified shielding agent, vulcanizing agent and fumed silica.

[0007] The rubber layer B is prepared from methyl vinyl phenyl silicone rubber, lead, fumed silica and vulcanizing agent.

[0008] The modified shielding agent is prepared from metal oxide and silane coupling agent.

[0009] Preferably, the preparation method of the modified shielding agent is as follows:

[0010] The metal oxide, water and silane coupling agent are mixed, an acid catalyst is added to adjust the pH to 3-4, and then the reaction is carried out at elevated temperature to obtain the modified shielding agent.

[0011] Preferably, the metal oxide is selected from one or more of bismuth oxide, gadolinium oxide and erbium oxide, the silane coupling agent is selected from one or both of γ-mercaptopropyl triethoxysilane and vinyl triethoxysilane; the mass ratio of the metal oxide and water is (5-10):100; the mass ratio of the metal oxide and the silane coupling agent is 100:(5-8).

[0012] Preferably, in the rubber layer A, the content of the methyl vinyl phenyl silicone rubber is 100 parts by weight, the content of the modified shielding agent is 50-100 parts by weight, the content of the fumed silica is 3-5 parts by weight, and the content of the vulcanizing agent is 1-2 parts by weight.

[0013] Preferably, in the rubber layer B, the content of the methyl vinyl phenyl silicone rubber is 100 parts by weight, the content of the lead is 200-400 parts by weight, the content of the fumed silica is 3-5 parts by weight, and the content of the vulcanizing agent is 1-2 parts by weight.

[0014] The application also provides a preparation method of the γ-ray-proof silicone rubber composite material, comprising the following steps:

[0015] Mixing the metal oxide, water and silane coupling agent, adjusting the pH and then heating to react to obtain the modified shielding agent;

[0016] Mixing the toluene vinyl phenyl silicone rubber, adding the modified shielding agent and mixing again, adding the fumed silica and the vulcanizing agent to obtain the rubber mixture A;

[0017] Mixing the methyl vinyl phenyl silicone rubber, adding the lead powder and mixing again, adding the fumed silica and the vulcanizing agent to obtain the rubber mixture B;

[0018] Cold pressing the rubber mixture A and the rubber mixture B respectively to obtain the rubber layer A and the rubber layer B;

[0019] Alternately stacking the rubber layer A and the rubber layer B with the rubber layer B arranged in the inner layer, vulcanizing and finally heat treating to obtain the γ-ray-proof silicone rubber composite material.

[0020] Preferably, in the step of preparing the rubber mixture A, the modified shielding agent is added for 5-10 times, the mixing time is 5-10 min, the mixing time again is 3-5 min; the content of the phenyl group in the methyl vinyl phenyl silicone rubber is 10-30 wt%, the weight average molecular weight is 40-80 w, the particle size of the fumed silica is 20-40 nm, the specific surface area is 150-300 m 2 / g, and the vulcanizing agent is selected from one or both of 2,5-dimethyl-2,5-di(tert-butyl peroxy) hexane and 2,4-dichloro peroxo benzoyl.

[0021] Preferably, in the step of preparing the rubber B, the lead powder is added for 5-10 times, the mixing time is 5-10 min, the re-mixing time is 3-5 min; the methyl vinyl phenyl silicone rubber has a phenyl content of 10-30 wt%, a weight average molecular weight of 40-80 w, the fumed silica has a particle size of 20-40 nm, a specific surface area of 150-300 m 2 / g, the lead powder has a particle size of 1-5 μm, and the vulcanizing agent is selected from one or both of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and 2,4-dichlorobenzoyl peroxide;

[0022] The thickness of the rubber layer A is 0.1-0.5 mm, and the thickness of the rubber layer B is 0.1-0.5 mm.

[0023] Preferably, the vulcanization temperature is 150-180 °C, and the time is 5-15 min, and the heat treatment temperature is 200-250 °C, and the time is 20-40 min.

[0024] The application also provides a gamma ray-proof product comprising a gamma ray-proof silicone rubber composite material, which is the gamma ray-proof silicone rubber composite material or the gamma ray-proof silicone rubber composite material prepared by the preparation method.

[0025] The application provides a gamma ray-proof silicone rubber composite material, which is composed of a plurality of rubber layer units, the rubber layer units comprise rubber layers A and rubber layers B arranged alternately, and the rubber layers B are arranged in the inner layer of the composite material; the composite material provided by the application has a multi-layer alternating structure, and the rubber layers containing lead are arranged in the inner layer of the composite material, so that direct contact of lead is avoided, the weak absorption area of the lead / silicone rubber composite material is compensated, a modified shielding agent is introduced into the rubber layer A, the shielding agent has good dispersity, and the shielding performance of the composite material in an irradiation environment can be improved; further, the silicone rubber molecules used in the composite material provided by the application introduce phenyl groups, the introduction of the phenyl groups improves the irradiation resistance of the composite material, and further improves the service life of the protective equipment in the irradiation environment.

[0026] Further, the composite material provided by the application has excellent mechanical properties, solvent resistance, cold resistance and interlayer adhesion by selection of the materials of the layers. DETAILED DESCRIPTION

[0027] In order to further understand the application, the preferred embodiments of the application are described below in combination with examples, but it should be understood that the description is only for further illustrating the features and advantages of the application, and is not a limitation on the claims of the application.

[0028] In view of the problems of direct contact with lead and weak absorption area of lead in the prior art, the gamma ray silicone rubber composite material is provided by arranging a plurality of alternating rubber layer A and rubber layer B, and the rubber layer B is arranged in the inner layer of the composite material, so that the obtained composite material can avoid direct contact with lead, and the problem of reducing the shielding rate due to the weak absorption area of lead is solved. Specifically, the gamma ray resistant silicone rubber composite material is disclosed by the embodiments of the present application, which is composed of a plurality of rubber layer units, the rubber layer unit includes alternating rubber layer A and rubber layer B, and the rubber layer B is arranged in the inner layer of the composite material.

[0029] The rubber layer A is prepared from methyl vinyl phenyl silicone rubber, modified shielding agent, vulcanizing agent and fumed silica.

[0030] The rubber layer B is prepared from methyl vinyl phenyl silicone rubber, lead, fumed silica and vulcanizing agent.

[0031] The modified shielding agent is prepared from metal oxide and silane coupling agent.

[0032] The gamma ray resistant silicone rubber composite material provided by the present application includes alternating rubber layer A and rubber layer B in a single rubber layer unit, and a plurality of rubber layer units can exist in the composite material, and the rubber layer B is arranged in the inner layer of the composite material, i.e. the composite material can have the following structure: rubber layer A / rubber layer B / rubber layer A / rubber layer B / rubber layer A.

[0033] In the present application, the rubber layer A is prepared from methyl vinyl phenyl silicone rubber, modified shielding agent, vulcanizing agent and fumed silica; specifically, the content of the methyl vinyl phenyl silicone rubber is 100 parts by weight, the content of the modified shielding agent is 50-100 parts by weight, the content of the fumed silica is 3-5 parts by weight, and the content of the vulcanizing agent is 1-2 parts by weight; more specifically, the content of the modified shielding agent is 60-90 parts by weight, and more specifically, the content of the modified shielding agent is 75-85 parts by weight. The content of the fumed silica is 3 parts by weight, 4 parts by weight or 5 parts by weight, and the content of the vulcanizing agent is 1 part by weight or 2 parts by weight. Among them, the phenyl in the methyl vinyl phenyl silicone rubber endows the material with radiation resistance, the modified shielding agent improves the gamma ray shielding performance of the material, and makes up for the weak absorption area of lead.

[0034] In the rubber layer A, the vulcanizing agent is selected from one or more of 2,5-dimethyl-2,5-di(tert-butyl peroxy)hexane and 2,4-dichloro peroxide benzoyl.

[0035] In the rubber layer A, the preparation method of the modified shielding agent is specifically as follows:

[0036] Mixing metal oxide, water and silane coupling agent, adding acid catalyst to adjust pH to 3-4, warming to react to obtain modified shielding agent.

[0037] In the preparation process of the modified shielding agent, the metal oxide is selected from one or more of bismuth oxide, gadolinium oxide and erbium oxide, and the silane coupling agent is selected from one or both of γ-mercapto propyl triethoxysilane and vinyl triethoxysilane. The mass ratio of the metal oxide to water is (5-10):100; the mass ratio of the metal oxide to the silane coupling agent is 100:(5-8); specifically, the mass ratio of the metal oxide to water is 5:100, 6:100, 7:100, 8:100, 9:100 or 10:100, and the mass ratio of the metal oxide to the silane coupling agent is 100:5, 100:6, 100:7 or 100:8. The temperature of the warming is 70-100℃, and the reaction time is 6-8h.

[0038] In the preparation process of the modified shielding agent, the metal oxide is surface-modified by coupling reaction, so that the obtained shielding modifier has better dispersibility, thereby improving the shielding performance of the composite material.

[0039] In the rubber layer B, the content of the methyl vinyl phenyl silicone rubber is 100 parts by weight, the content of the lead is 200-400 parts by weight, the content of the fumed silica is 3-5 parts by weight, and the content of the vulcanizing agent is 1-2 parts by weight; specifically, the content of the lead is 250-380 parts by weight, more specifically, the content of the lead is 300-350 parts by weight, the content of the fumed silica is 3 parts by weight, 4 parts by weight or 5 parts by weight, and the content of the vulcanizing agent is 1 part by weight or 2 parts by weight. In the present application, the vulcanizing agent is selected from one or more of 2,5-dimethyl-2,5-di(tert-butyl peroxy)hexane and 2,4-dichloro peroxyl benzoyl. Among them, the phenyl in the methyl vinyl phenyl silicone rubber endows the material with radiation resistance, and the lead improves the γ-ray shielding performance of the material.

[0040] The present application also provides a preparation method of a γ-ray shielding silicone rubber composite material, comprising the following steps:

[0041] Mixing metal oxide, water and silane coupling agent, adjusting pH and warming to react to obtain a modified shielding agent;

[0042] Mixing toluene styrene phenyl silicone rubber, adding the modified shielding agent, mixing again, adding fumed silica and a vulcanizing agent to obtain a rubber compound A;

[0043] Mixing methyl vinyl phenyl silicone rubber, adding lead powder, mixing again, adding fumed silica and a vulcanizing agent to obtain a rubber compound B;

[0044] The rubber layer A and the rubber layer B are alternately stacked and placed, and the rubber layer B is arranged in the inner layer and post-cured, and finally heat treated to obtain a γ-ray shielding silicone rubber composite material.

[0045] The rubber layer A and the rubber layer B are alternately stacked and placed, and the rubber layer B is arranged in the inner layer and post-cured, and finally heat treated to obtain a γ-ray shielding silicone rubber composite material.

[0046] In the preparation process of the γ-ray shielding silicone rubber composite material, the modified shielding agent is first prepared, which has been described in detail above and will not be repeated here.

[0047] The rubber layer A and the rubber layer B are alternately stacked and placed, and the rubber layer B is arranged in the inner layer and post-cured, and finally heat treated to obtain a γ-ray shielding silicone rubber composite material.

[0048] The methyl vinyl phenyl silicone rubber is mixed, the modified shielding agent is added in multiple times for continuous mixing, then fumed silica is added, and the vulcanizing agent is added after uniform mixing to obtain the rubber mixture A.

[0049] In the above process, the mixing time is 5-10 min, the continuous mixing time is 3-5 min, and the modified shielding agent is added in 5-10 times for uniform dispersion. In the present application, the phenyl content (Ph / Si) of the methyl vinyl phenyl silicone rubber is 10-30 wt%, and the weight average molecular weight is 40-80 w; more specifically, the phenyl content (Ph / Si) of the methyl vinyl phenyl silicone rubber is 15-25 wt%, and the weight average molecular weight is 50-70 w. The particle size of the fumed silica is 20-40 nm, and the specific surface area is 150-300 m 2 / g; specifically, the particle size of the fumed silica is 25-35 nm, and the specific surface area is 180-250 m 2 / g. The vulcanizing agent is selected from one or more of 2,5-dimethyl-2,5-di(tert-butyl peroxy) hexane and 2,4-dichloro peroxide benzoyl.

[0050] The preparation method of the rubber mixture B is as follows: after the methyl vinyl phenyl silicone rubber is mixed, the lead powder is added in multiple times for continuous mixing, then the fumed silica and the vulcanizing agent are added, and finally mixed.

[0051] In the above process, the mixing time is 5-10 min, and the continued mixing time is 3-5 min. In order to realize uniform dispersion of the lead powder, the lead powder is added in 5-10 times. In the present application, the phenyl content (Ph / Si) of the methyl vinyl phenyl silicone rubber is 10-30 wt%, and the weight average molecular weight is 40-80 w; more specifically, the phenyl content (Ph / Si) of the methyl vinyl phenyl silicone rubber is 15-25 wt%, and the weight average molecular weight is 50-70 w. The particle size of the fumed silica is 20-40 nm, and the specific surface area is 150-300 m 2 / g; specifically, the particle size of the fumed silica is 25-35 nm, and the specific surface area is 180-250 m 2 / g. The particle size of the lead powder is 1-2 μm. The vulcanizing agent is selected from one or more of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and 2,4-dichlorobenzoyl peroxide.

[0052] The present application then respectively cold-presses the above-obtained rubber A and rubber B to obtain rubber layer A and rubber layer B with a thickness of 0.2-0.5 mm. The cold-pressing is a technical means well known to those skilled in the art, and the present application does not make a special limitation thereto.

[0053] The present application finally vulcanizes, i.e. places rubber layer A, rubber layer B, rubber layer A, rubber layer B, rubber layer A, and the like in a stacked manner, and needs to ensure that rubber layer B is arranged in the inner layer, and then performs heat treatment after vulcanization. The vulcanization temperature is 150-180℃, and the time is 5-15 min; the heat treatment temperature is 200-250℃, and the time is 20-40 min; specifically, the vulcanization temperature is 150-170℃, and the time is 8-10 min; the heat treatment temperature is 210-240℃, and the time is 25-35 min.

[0054] The present application adopts shielding agent modification and silicone rubber mixing to prepare a multi-layer composite γ-ray shielding silicone rubber composite material. The composite material has a multi-layer alternating structure, which makes up for the weak absorption zone of the lead / silicone rubber composite material, improves the shielding rate of the composite material at 59.5 keV (the intensity of the radiation source), and avoids direct contact of lead with the human body, thereby improving the use safety. Further, the introduction of phenyl groups into the silicone rubber molecules improves the radiation resistance of the composite material, thereby improving the service life of the prepared protective equipment in the irradiation environment.

[0055] The γ-ray shielding silicone rubber composite material prepared by the present application also has excellent mechanical properties, solvent resistance, cold resistance, and interlayer adhesion.

[0056] Therefore, the prepared anti-gamma ray silicon rubber composite material has wide application prospects in the field of anti-gamma ray protective equipment resistant to irradiation.

[0057] Further, the application also provides an anti-gamma ray product comprising the anti-gamma ray silicon rubber composite material, wherein the anti-gamma ray silicon rubber composite material is the anti-gamma ray silicon rubber composite material described in the above solution.

[0058] In order to further understand the application, the anti-gamma ray silicon rubber composite material and the preparation method thereof provided by the application are described in detail below in combination with examples, and the protection scope of the application is not limited by the following examples.

[0059] Example 1

[0060] (1) Modification of shielding agent: 200 g of bismuth oxide with a particle size of 2 μm was put into a three-necked flask, and 2000 g of water and 16 g of γ-mercaptopropyl triethoxysilane were added into the three-necked flask, then formic acid catalyst was added to adjust the pH to 5, and in the acidic environment, the temperature was increased to 90 °C for 8 h, then the modified shielding agent was filtered and dried in an oven to obtain the modified shielding agent;

[0061] (2) Mixing rubber A: 100 grams of methyl vinyl phenyl silicone rubber (phenyl content of 30%, molecular weight of 80w) was mixed on an open mill for 10 min, 100 grams of modified shielding agent was added in 10 times, and mixing was continued for 5 min, 5 grams of fumed silica (particle size of 40 nm, specific surface area of 150 m 2 / g) was added, and after mixing uniformly, 2 grams of 2,5-dimethyl-2,5-di(tert-butyl peroxy) hexane was added, and after mixing uniformly, it was ready for use;

[0062] Mixing rubber B: 100 grams of methyl vinyl phenyl silicone rubber (phenyl content of 30%, molecular weight of 80w) was mixed on an open mill for 10 min, 400 grams of 2 μm lead powder was added in 10 times, and mixing was continued for 5 min, 5 grams of fumed silica was added, and after mixing uniformly, 2 grams of 2,5-dimethyl-2,5-di(tert-butyl peroxy) hexane was added, and after mixing uniformly, it was ready for use;

[0063] (3) Cold pressing: the mixing rubber obtained in steps (1) and (2) was pressed into a 0.5 mm thick sheet using a molding die to obtain rubber layer A and rubber layer B;

[0064] (4) Vulcanization: rubber layer A / rubber layer B / rubber layer A / rubber layer B / rubber layer A was placed in the mold alternately, and vulcanized at 170 °C for 15 min, and then demolded, and post-treated at 220 °C for 40 min to obtain the anti-gamma ray silicon rubber composite material.

[0065] Example 2

[0066] (1) Shielding agent modification: first, 200 g of bismuth oxide with a particle size of 2 μm was placed in a three-necked flask, 4000 g of water and 10 g of γ-mercaptopropyl triethoxysilane were added into the three-necked flask, then formic acid catalyst was added to adjust the pH to 5, in the acidic environment, the temperature was raised to 90°C for 8h, then the modified shielding agent was filtered and dried in an oven to obtain the modified shielding agent;

[0067] (2) Mixing rubber A: 100 grams of methyl vinyl phenyl silicone rubber (phenyl content 30%, molecular weight 80w) was mixed on an open mill for 10 min, 75 grams of modified shielding agent was added in 10 times, and mixing was continued for 5 min, 5 grams of fumed silica (particle size 40 nm, specific surface area 150 m 2 / g) was added, and after mixing evenly, 2 grams of 2,5-dimethyl-2,5-di(tert-butyl peroxy) hexane was added, and after mixing evenly, it was ready for use;

[0068] Mixing rubber B: 100 grams of methyl vinyl phenyl silicone rubber (phenyl content 30%, molecular weight 80w) was mixed on an open mill for 10 min, 300 grams of 2 μm lead powder was added in 10 times, and mixing was continued for 5 min, 5 grams of fumed silica was added, and after mixing evenly, 2 grams of 2,5-dimethyl-2,5-di(tert-butyl peroxy) hexane was added, and after mixing evenly, it was ready for use;

[0069] (3) Cold pressing: the mixing rubber obtained in steps (1), (2) was pressed into a 0.5 mm thick sheet with a molding die to obtain rubber layer A and rubber layer B;

[0070] (4) Vulcanization: rubber layer A / rubber layer B / rubber layer A / rubber layer B / rubber layer A was placed in the mold alternately, and vulcanized at 170°C for 15 min, and then demolded, and post-treated at 220°C for 40 min to obtain a γ-ray shielding silicone rubber composite material.

[0071] Example 3

[0072] (1) Shielding agent modification: first, 200 g of bismuth oxide with a particle size of 2 μm was placed in a three-necked flask, 2000 g of water and 16 g of γ-mercaptopropyl triethoxysilane were added into the three-necked flask, then formic acid catalyst was added to adjust the pH to 5, in the acidic environment, the temperature was raised to 90°C for 8h, then the modified shielding agent was filtered and dried in an oven to obtain the modified shielding agent;

[0073] (2) Mixing rubber A: 100 grams of methyl vinyl phenyl silicone rubber (phenyl content of 30%, molecular weight of 80w) was mixed on an open mill for 10 minutes, 50 grams of modified shielding agent was added in 10 portions, and mixing was continued for 5 minutes, 5 grams of fumed silica (particle size of 40 nm, specific surface area of 150 m 2 / g) was added, and after uniform mixing, 2 grams of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane was added, and after uniform mixing, it was reserved;

[0074] Mixing rubber B: 100 grams of methyl vinyl phenyl silicone rubber (phenyl content of 30%, molecular weight of 80w) was mixed on an open mill for 10 minutes, 300 grams of 2 μm lead powder was added in 10 portions, and mixing was continued for 5 minutes, 5 grams of fumed silica was added, and after uniform mixing, 2 grams of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane was added, and after uniform mixing, it was reserved;

[0075] (3) Cold press forming: the mixing rubber obtained in steps (1), (2) was pressed into a 0.5 mm thick sheet using a forming mold to obtain rubber layer A and rubber layer B;

[0076] (4) Vulcanization: rubber layer A / rubber layer B / rubber layer A / rubber layer B / rubber layer A was placed alternately in a mold, and vulcanized at 170°C for 15 minutes, and then demolded, and post-treated at 220°C for 40 minutes to obtain a γ-ray shielding silicone rubber composite material.

[0077] Example 4

[0078] (1) Shielding agent modification: first, 200 g of gadolinium oxide with a particle size of 1 μm was placed in a three-necked flask, 2000 g of water and 16 g of vinyl triethoxysilane were added to the three-necked flask, then formic acid catalyst was added to adjust the pH to 4, and in the acidic environment, the temperature was raised to 70°C and reacted for 6 h, then the modified shielding agent was filtered and dried in an oven to obtain the modified shielding agent;

[0079] (2) Mixing rubber A: 100 grams of methyl vinyl phenyl silicone rubber (phenyl content of 10%, molecular weight of 40w) was mixed on an open mill for 5 minutes, 100 grams of modified shielding agent was added in 5 portions, and mixing was continued for 3 minutes, 3 grams of fumed silica (particle size of 20 nm, specific surface area of 300 m 2 / g) was added, and after uniform mixing, 1 gram of 2,4-dichlorobenzoyl peroxide was added, and after uniform mixing, it was reserved;

[0080] Compound B: 100 grams of methyl vinyl phenyl silicone rubber (phenyl content of 10%, molecular weight of 40w) was mixed on an open mill for 5 minutes, 400 grams of 1 μιη lead powder was added in 5 portions, and mixing was continued for 3 minutes, 3 grams of fumed silica (particle size of 20 nm, specific surface area of 300 m 2 / g) was added, and after uniform mixing, 1 gram of 2,4-dichlorobenzoyl peroxide was added, and after uniform mixing, it was reserved for use;

[0081] (3) Cold press molding: the compounds obtained in steps (1), (2) were respectively pressed into 0.2 mm thick sheets using a molding die, to obtain rubber layer A and rubber layer B;

[0082] (4) Vulcanization: rubber layer A / rubber layer B / rubber layer A / rubber layer B / rubber layer A were alternately placed in a mold, and vulcanized at 150°C for 5 minutes, and after demolding, post-treatment at 200°C for 20 minutes was performed, to obtain a γ-ray shielding silicone rubber composite material.

[0083] Example 5

[0084] (1) Shielding agent modification: first, 200 g of 1 μιη particle size erbium oxide was placed in a three-necked flask, and 2000 g of water and 16 g of vinyl triethoxysilane were added to the three-necked flask, and then formic acid catalyst was added to adjust the pH to 4, and in the acidic environment, the temperature was raised to 70°C and reacted for 6 h, and then the modified shielding agent after the reaction was filtered and dried in an oven, to obtain a modified shielding agent;

[0085] (2) Compound A: 100 grams of methyl vinyl phenyl silicone rubber (phenyl content of 10%, molecular weight of 40w) was mixed on an open mill for 5 minutes, 100 grams of modified shielding agent was added in 5 portions, and mixing was continued for 3 minutes, 3 grams of fumed silica (particle size of 20 nm, specific surface area of 300 m 2 / g) was added, and after uniform mixing, 1 gram of 2,4-dichlorobenzoyl peroxide was added, and after uniform mixing, it was reserved for use;

[0086] Compound B: 100 grams of methyl vinyl phenyl silicone rubber (phenyl content of 10%, molecular weight of 40w) was mixed on an open mill for 5 minutes, 400 grams of 1 μιη lead powder was added in 5 portions, and mixing was continued for 3 minutes, 3 grams of fumed silica (particle size of 20 nm, specific surface area of 300 m 2 / g) was added, and after uniform mixing, 1 gram of 2,4-dichlorobenzoyl peroxide was added, and after uniform mixing, it was reserved for use;

[0087] (3) Cold press molding: the compounds obtained in steps (1), (2) were respectively pressed into 0.2 mm thick sheets using a molding die, to obtain rubber layer A and rubber layer B;

[0088] (4) Vulcanization: The rubber layer A / rubber layer B / rubber layer A / rubber layer B / rubber layer A were alternately placed in a mold, and vulcanized at 150°C for 5 min, followed by demolding, and post-treated at 200°C for 20 min to obtain a γ-ray shielding silicone rubber composite.

[0089] Comparative Example 1

[0090] (1) Rubber mixture A: 100 g of methyl vinyl silicone rubber (not containing phenyl group, molecular weight 80w) was mixed on an open mill for 10 min, 50 g of bismuth oxide with a particle size of 2 μm was added in 10 portions, and mixing was continued for 5 min, 5 g of fumed silica (particle size 40 nm, specific surface area 150 m 2 / g) was added, and after uniform mixing, 2 g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane was added, and after uniform mixing, it was reserved;

[0091] Rubber mixture B: 100 g of methyl vinyl silicone rubber (not containing phenyl group, molecular weight 80w) was mixed on an open mill for 10 min, 300 g of 2 μm lead powder was added in 10 portions, and mixing was continued for 5 min, 5 g of fumed silica was added, and after uniform mixing, 2 g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane was added, and after uniform mixing, it was reserved;

[0092] (2) Cold press molding: The rubber mixtures obtained in steps (1) and (2) were respectively pressed into 0.5 mm thick sheets using a molding die to obtain rubber layer A and rubber layer B;

[0093] (3) Vulcanization: The rubber layer A / rubber layer B / rubber layer A / rubber layer B / rubber layer A were alternately placed in a mold, and vulcanized at 170°C for 15 min, followed by demolding, and post-treated at 220°C for 40 min to obtain Comparative Sample 1.

[0094] Comparative Example 2

[0095] (1) Rubber mixture: 200 g of methyl vinyl phenyl silicone rubber (phenyl group content 30%, molecular weight 80w) was mixed on an open mill for 10 min, 50 g of bismuth oxide with a particle size of 2 μm was added in 10 portions, and mixing was continued for 5 min; 300 g of 2 μm lead powder was added in 10 portions, and mixing was continued for 5 min, 10 g of fumed silica was added, and after uniform mixing, 4 g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane was added, and after uniform mixing, it was reserved;

[0096] (2) Cold press molding: The rubber mixture obtained in step (1) was pressed into a 0.5 mm thick sheet using a molding die;

[0097] (3) Cure: 5 layers of the compounded rubber were placed in a mold and cured at 170 °C for 15 min, followed by post cure at 220 °C for 40 min after demolding to obtain Comparative Sample 2.

[0098] The properties of the composite materials prepared in the test examples and comparative examples were tested, and the test results are shown in Table 1.

[0099] Table 1 Properties of the composite materials prepared in the test examples and comparative examples

[0100]

[0101]

[0102] The above description of the embodiments is only used to help understand the method of the present application and its core idea. It should be noted that for those skilled in the art, some improvements and modifications can be made to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

[0103] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to the embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A gamma ray proof silicone rubber composite material, comprising a plurality of rubber layer units, wherein the rubber layer units comprise rubber layer A and rubber layer B arranged alternately, and the rubber layer B is arranged in the inner layer of the composite material; the rubber layer A is prepared from methyl vinyl phenyl silicone rubber, modified shielding agent, vulcanizing agent and fumed silica; the rubber layer B is prepared from methyl vinyl phenyl silicone rubber, lead, fumed silica and vulcanizing agent; the modified shielding agent is prepared from metal oxide and silane coupling agent, and the metal oxide is selected from one or more of bismuth oxide, gadolinium oxide and erbium oxide. The preparation method of the modified shielding agent comprises the following steps: mixing metal oxide, water and silane coupling agent, adjusting pH to 3-4 by adding acid catalyst, and then heating to obtain the modified shielding agent. The silane coupling agent is selected from one or both of γ-mercaptopropyl triethoxysilane and vinyl triethoxysilane; the mass ratio of the metal oxide to water is (5-10) : 100; and the mass ratio of the metal oxide to the silane coupling agent is 100: (5-8). In the rubber layer A, the content of the methyl vinyl phenyl silicone rubber is 100 parts by weight, the content of the modified shielding agent is 50-100 parts by weight, the content of the fumed silica is 3-5 parts by weight, and the content of the vulcanizing agent is 1-2 parts by weight.

2. The gamma ray resistant silicone rubber composite of claim 1, wherein, In the rubber layer B, the content of the methyl vinyl phenyl silicone rubber is 100 parts by weight, the content of the lead is 200-400 parts by weight, the content of the fumed silica is 3-5 parts by weight, and the content of the vulcanizing agent is 1-2 parts by weight. 6.A preparation method of the gamma ray proof silicone rubber composite material according to claim 1, comprising the following steps: mixing metal oxide, water and silane coupling agent, adjusting pH and then heating to obtain the modified shielding agent; mixing methyl vinyl phenyl silicone rubber, adding the modified shielding agent and mixing again, adding fumed silica and vulcanizing agent to obtain rubber layer A; mixing methyl vinyl phenyl silicone rubber, adding lead powder and mixing again, adding fumed silica and vulcanizing agent to obtain rubber layer B; cold pressing the rubber layer A and the rubber layer B to obtain rubber layer A and rubber layer B; and stacking the rubber layer A and the rubber layer B alternately with the rubber layer B arranged in the inner layer, and then vulcanizing and finally heat treating to obtain the gamma ray proof silicone rubber composite material.

3. The gamma ray resistant silicone rubber composite of claim 2, wherein, The thickness of the rubber layer A is 0.1-0.5 mm, and the thickness of the rubber layer B is 0.1-0.5 mm.

4. The gamma ray resistant silicone rubber composite of claim 1, wherein The vulcanization temperature is 150-180℃, the vulcanization time is 5-15 min, the heat treatment temperature is 200-250℃, and the heat treatment time is 20-40 min.

5. The gamma ray resistant silicone rubber composite of claim 1, wherein 10.A gamma ray proof product, comprising the gamma ray proof silicone rubber composite material according to any one of claims 1-5 or prepared by the preparation method according to any one of claims 6-9. ​ ​ ​ ​ ​ ​ 7. The preparation method according to claim 6, characterized in that, In the step of preparing the rubber compound A, the modified shielding agent is added for 5-10 times, the mixing time is 5-10 min, the re-mixing time is 3-5 min; the methyl vinyl phenyl silicone rubber has a phenyl content of 10-30 wt%, a weight average molecular weight of 40-80 w, the fumed silica has a particle size of 20-40 nm, a specific surface area of 150-300 m 2 / g, and the vulcanizing agent is selected from one or both of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and 2,4-dichlorobenzoyl peroxide.

8. The preparation method according to claim 6, characterized in that, In the step of preparing the rubber compound B, the lead powder is added for 5 to 10 times, the mixing time is 5 to 10 minutes, and the re-mixing time is 3 to 5 minutes; the methyl vinyl phenyl silicone rubber has a phenyl content of 10 to 30 wt%, and a weight average molecular weight of 40 to 80 w; the fumed silica has a particle size of 20 to 40 nm, and a specific surface area of 150 to 300 m 2 / g; the lead powder has a particle size of 1 to 5 μm; and the vulcanizing agent is selected from one or both of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and 2,4-dichlorobenzoyl peroxide. ​ 9. The preparation method according to claim 6, characterized in that, ​ ​

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