A low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties, its preparation method, and its applications.

Abstract

This application belongs to the field of silicone rubber technology, and particularly relates to a low-volatility electromagnetic shielding silicone rubber with excellent mechanical properties, its preparation method, and its application. The silicone rubber provided in this application includes: a first organosilicon raw rubber, a second organosilicon raw rubber, a vulcanizing agent, an inorganic reinforcing filler, a surface treatment modifier, a structure control agent, a release agent, and a metal-doped modified polyhedral oligomeric silsesquioxane, etc. A high crosslinking density silicone rubber is constructed by using a first organosilicon raw rubber with low vinyl content and high molecular weight and a second organosilicon raw rubber with high vinyl content and low molecular weight. By taking advantage of the R groups in the metal-doped modified polyhedral oligomeric silsesquioxane and the doped metal R′ groups, the electromagnetic shielding performance and mechanical properties of the silicone rubber are significantly improved, and the volatility is reduced, thereby improving the overall performance of the silicone rubber and solving the technical problem of poor overall performance of silicone rubber in the prior art.

Description

Technical Field

[0001] This application belongs to the field of vulcanized silicone rubber technology, and particularly relates to a low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties, its preparation method and application. Background Technology

[0002] Vulcanized silicone rubber, a type of silicone rubber, is an indispensable material in the industrial field. It has advantages in terms of cost and is widely used in industrial fields such as building waterproof sealants and electrical insulators.

[0003] Beyond its applications in traditional industries, emerging sectors such as 5G communications, new energy, and artificial intelligence are driving the development of silicone rubber towards high precision and high added value, placing new performance demands on it. In applications like outdoor 5G base stations, new energy vehicle power batteries, and energy storage systems, silicone rubber needs to withstand complex conditions such as vibration, high and low temperature cycling, and humid environments, requiring it to maintain good mechanical properties. Furthermore, high-precision components such as chips, radio frequency modules, and optical communication components inside high-power 5G base stations or AI servers have high cleanliness requirements, necessitating the prevention of volatile small molecules from silicone rubber contaminating these precision devices during service to ensure long-term stable operation. Additionally, electronic devices may interfere with other electronic devices due to electromagnetic waves during operation. With the compact internal structure of AI servers and the high frequency of 5G, complex electromagnetic environments are generated, placing even higher demands on the electromagnetic shielding performance of silicone rubber.

[0004] Within the industry, some vulcanized silicone rubbers are modified with metal oxides and inorganic conductive nanomaterials to impart electromagnetic shielding properties. However, these inorganic materials are not well-compatible with silicone rubber, exhibiting poor dispersibility and stability, and are prone to agglomeration. This leads to a decline in both the electromagnetic shielding and mechanical properties of the silicone rubber. Furthermore, these inorganic materials are typically added before the vulcanization reaction, which may interfere with the reaction, resulting in incomplete curing and the presence of unreacted small molecules, leading to volatility defects. Consequently, silicone rubber modified with inorganic materials such as metal oxides and inorganic conductive nanomaterials exhibits poor overall performance, making it difficult to meet the requirements of emerging industries such as 5G communication, new energy, and artificial intelligence. Therefore, it is necessary to develop a new type of silicone rubber. Summary of the Invention

[0005] In view of this, this application provides a low-volatility electromagnetic shielding silicone rubber with excellent mechanical properties, its preparation method, and its application, in order to solve the technical problem of poor overall performance of silicone rubber in the prior art.

[0006] The first aspect of this application provides a low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties, comprising: organosilicon raw rubber, vulcanizing agent, inorganic reinforcing filler, surface treatment agent, structure control agent, release agent, and metal-doped modified polyhedral oligomeric silsesquioxane.

[0007] The organosilicon raw rubber includes: a first organosilicon raw rubber and a second organosilicon raw rubber, wherein the vinyl content of the first organosilicon raw rubber is less than that of the second organosilicon raw rubber, and the molecular weight is greater than that of the second organosilicon raw rubber.

[0008] Preferably, the metal-doped modified polyhedral oligomeric silsesquioxane is selected from at least one metal-doped modified polyhedral oligomeric silsesquioxane from Al, Ti, Ni, and Fe; its general formula is: T8R7R′; in the general formula, the R group is hydroxyl, methyl, phenyl, vinyl, carboxyl, isobutyl, allyl, alkoxy, epoxy, or cyclohexyl, and the R′ group is doped with at least one metal from Al, Ti, Ni, and Fe.

[0009] Preferably, the organosilicon raw rubber is selected from at least two of vinyl-terminated polydimethylsiloxane, vinyl-terminated polydimethyl-methylvinylsiloxane, polydimethyl-methylvinylsiloxane, vinyl-terminated polymethylphenylsiloxane, dimethylvinyl-terminated polydimethylsiloxane, dimethylvinyl-terminated polydimethyl-methylvinylsiloxane, methyl-terminated polymethylvinylsiloxane, polydimethylsiloxane, and hydroxyl-terminated polymethylvinylsiloxane; the organosilicon raw rubber has an alkenyl content of 0.01-2% and a molecular weight of 350,000-700,000;

[0010] The vulcanizing agent is selected from at least one of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (bis-2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane), 2,4-dichlorobenzoyl peroxide, platinum catalyst combined with hydrogen-containing silicone oil, bis-(2,4-dichlorobenzoyl peroxide), benzoyl peroxide, and dicumyl peroxide.

[0011] Preferably, the organosilicon raw rubber comprises: a first organosilicon raw rubber with a vinyl content of 0.01% to 0.05% and a molecular weight of 500,000 to 700,000, and a second organosilicon raw rubber with a vinyl content of 1% to 5% and a molecular weight of 400,000 to 550,000.

[0012] Preferably, the inorganic reinforcing filler is selected from at least one of fumed silica, nano-calcium carbonate, and silica powder;

[0013] The surface treatment agent is selected from at least one of the following: hydroxyl-terminated polydimethylsiloxane (hydroxyl silicone oil), hexamethyldisilazane, vinylsilazane, vinyl hydroxyl-terminated polydimethylsiloxane, dimethyldimethoxysilane, dimethyldiethoxysilane, methyltrimethoxysilane, vinyltriethoxysilane, glycidylpropyltrimethoxysilane, methacrylate-propyltrimethoxysilane, and octamethylcyclotetrasiloxane;

[0014] The structuring control agent is selected from at least one of the following: hydroxyl silicone oil and other oligopolysiloxanes containing hydroxyl or alkoxy groups, alkylsilanols such as trimethylsilanol, phenylsilanols, diol compounds, silanes containing hydroxyl or alkoxy groups, and hydroxyl-terminated polymethylvinylsiloxanes.

[0015] The release agent is selected from at least one of stearic acid, zinc stearate, calcium stearate, barium stearate, magnesium stearate, zinc laurate, magnesium laurate, palmitic acid, and lauric acid.

[0016] Preferably, the low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties, calculated by mass parts, comprises: 40-60 parts by mass of a first organosilicon raw rubber, 4-10 parts by mass of a second organosilicon raw rubber, 0.5-1.5 parts by mass of a vulcanizing agent, 35-45 parts by mass of an inorganic reinforcing filler, 2-5 parts by mass of a surface treatment agent, 0.5-1.5 parts by mass of a structuring control agent, 0.005-0.02 parts by mass of a release agent, and 1-10 parts by mass of a metal-doped modified polyhedral oligomeric silsesquioxane.

[0017] The second aspect of this application provides a method for preparing a low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties, which can prepare the low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties described in the first aspect, comprising the following steps:

[0018] By reacting POSS containing reactive groups with a metal source, metal-doped modified polyhedral oligomeric silsesquioxanes are obtained.

[0019] Inorganic reinforcing filler, surface treatment agent, and metal-doped modified polyhedral oligomeric silsesquioxane are added to the first organosilicon raw rubber and the second organosilicon raw rubber for a first compounding process to obtain a first compound.

[0020] The structure control agent and the release agent are added to the primary compound and then mixed again to obtain the secondary compound.

[0021] The vulcanizing agent is added to the secondary compound and subjected to open milling and vulcanization to obtain low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties.

[0022] Preferably, the reaction of POSS containing reactive groups and metal source includes: dispersing trisilyl isobutyl ester POSS or trisilyl phenyl POSS and metal source in an organic solvent under nitrogen and anhydrous conditions to obtain metal-doped modified polyhedral oligomeric silsesquioxane.

[0023] Preferably, the temperature of the first mixing is 130~150℃ and the time is 1~5h, and the temperature of the second mixing is 70~90℃ and the time is 0.5~2h.

[0024] The vulcanization process includes: vulcanizing at 150-180℃ for 5-20 minutes under a pressure of 10-15 MPa, and vulcanizing at 180-220℃ for 1-4 hours.

[0025] The third aspect of this application provides the application of a low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties, as described in the first aspect, in the fields of 5G communication, new energy, or artificial intelligence.

[0026] Compared with the prior art, the low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties provided in this application has at least the following beneficial effects:

[0027] 1. The vulcanized silicone rubber provided in this application, by introducing metal-doped modified polyhedral oligomeric silsesquioxane, utilizes the advantages of its R′ group-doped metal and R organic groups, which have good compatibility with vulcanized silicone rubber, few interface defects, and active sites that can participate in the vulcanization crosslinking system to increase the degree of crosslinking. This endows the vulcanized silicone rubber with excellent electromagnetic shielding, mechanical properties, and low volatility. At the same time, the octagonal hollow cage structure of POSS can achieve perfect encapsulation and entanglement with fillers and chain polysiloxanes, which promotes a significant enhancement of the mechanical properties of the cured structure, greatly improves the aging resistance, and greatly reduces the generation of low molecular weight volatile substances. It is a vulcanized silicone rubber with excellent comprehensive performance.

[0028] 2. The vulcanized silicone rubber provided in this application improves the overall performance of the vulcanized silicone rubber by simultaneously introducing a first organosilicon raw rubber with low vinyl content and high molecular weight and a second organosilicon raw rubber with high vinyl content and low molecular weight. The high molecular weight first organosilicon raw rubber serves as the main chain of the vulcanized silicone rubber, while the low molecular weight but high vinyl content second organosilicon raw rubber can introduce high crosslinking density between the main chains of the vulcanized silicone rubber. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the specific embodiments of this application or 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 this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This is a schematic flowchart illustrating a method for preparing a low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties, as provided in Embodiment 1 of this application. Detailed Implementation

[0031] This application provides a low-volatility electromagnetic shielding silicone rubber with excellent mechanical properties, its preparation method, and its application, in order to solve the technical problem of poor overall performance of silicone rubber in the prior art.

[0032] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0033] Example 1

[0034] This embodiment provides a method for preparing low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties, and the preparation flowchart is as follows. Figure 1 As shown, the process includes the preparation steps of metal-doped modified polyhedral oligomeric silsesquioxane, the raw material weighing step, the preparation step of the compound, and the vulcanization step.

[0035] The preparation steps of metal-doped modified polyhedral oligomeric silsesquioxanes include:

[0036] Weigh trisilyl isobutyl ester (POSS) and AlCl3 at a molar ratio of 1:1.05. Under a nitrogen atmosphere, dissolve the weighed POSS in a mixture of triethylamine and toluene, then add the weighed AlCl3 and stir to dissolve. Continue to purge under a N2 atmosphere for 30 min to remove air and moisture. Place the solution in a preheated environment at 60 °C for 24 h to remove the solvent, wash with methanol, and vacuum dry for 12 h to obtain aluminum-doped modified polyhedral oligomeric silsesquioxane.

[0037] The steps for weighing raw materials include:

[0038] According to the mass ratio of 50:5:1.2:40:4:1:0.01:2, the following raw materials were weighed as raw materials for vulcanized silicone rubber: vinyl-terminated polydimethylsiloxane (vinyl content 0.05%, molecular weight 600,000), vinyl-terminated polydimethyl-methylvinylsiloxane (vinyl content 0.8%, molecular weight 450,000), 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (bis-25), QS-20 silica, hydroxyl silicone oil, hydroxyl silicone oil (structure control agent, viscosity 50CS, hydroxyl content 8%), zinc stearate, and aluminum-doped modified polyhedral oligomeric silsesquioxane.

[0039] The preparation steps of the compound rubber include:

[0040] Under stirring, the weighed hydroxyl silicone oil is slowly added to a disperser containing QS-20 silica and dispersed for 30 minutes to mix evenly. The treated silica and the weighed aluminum-doped modified polyhedral oligomeric silsesquioxane are added in batches to a kneader containing vinyl-terminated polydimethylsiloxane and vinyl-terminated polydimethyl-methylvinylsiloxane. Under N2 conditions, the mixture is kneaded while the temperature is raised to 140°C. The mixture is kneaded for 5 hours and then cooled for 12 hours to obtain the first-component rubber compound.

[0041] The primary compound, hydroxyl silicone oil (structural control agent, viscosity 50CS, hydroxyl content 8%), and zinc stearate are placed in a kneader and kneaded at below 80°C for 1 hour for a secondary compounding to obtain the secondary compound.

[0042] The vulcanization process includes:

[0043] Weigh out 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (bis-2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane) and add it to the secondary compound for mixing. After mixing evenly, place it in a mold and vulcanize at 160°C for 10 min under a pressure of 13 MPa and then at 200°C for 4 h. Remove it and place it in a vacuum drying oven to cool to room temperature to obtain low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties.

[0044] Example 2

[0045] This embodiment provides a method for preparing low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties. The difference from Embodiment 1 is that the amount of metal-doped modified polyhedral oligomeric silsesquioxane is adjusted, including the preparation steps of the metal-doped modified polyhedral oligomeric silsesquioxane, the raw material weighing step, the preparation step of the compound, and the vulcanization step.

[0046] The preparation steps of metal-doped modified polyhedral oligomeric silsesquioxanes include:

[0047] Weigh trisilyl isobutyl ester (POSS) and AlCl3 at a molar ratio of 1:1.05. Under a nitrogen atmosphere, dissolve the weighed POSS in a mixture of triethylamine and toluene, then add the weighed AlCl3 and stir to dissolve. Continue to purge under a N2 atmosphere for 30 min to remove air and moisture. Place the solution in a preheated environment at 60 °C for 24 h to remove the solvent, wash with methanol, and vacuum dry for 12 h to obtain aluminum-doped modified polyhedral oligomeric silsesquioxane.

[0048] The steps for weighing raw materials include:

[0049] According to the mass ratio of 50:5:1.2:40:4:1:0.01:5, the following raw materials were weighed as raw materials for vulcanized silicone rubber: vinyl-terminated polydimethylsiloxane (vinyl content 0.05%, molecular weight 600,000), vinyl-terminated polydimethyl-methylvinylsiloxane (vinyl content 0.8%, molecular weight 450,000), 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (bis-25), QS-20 silica, hydroxyl silicone oil, hydroxyl silicone oil (structure control agent, viscosity 50CS, hydroxyl content 8%), zinc stearate, and aluminum-doped modified polyhedral oligomeric silsesquioxane.

[0050] The preparation steps of the compound rubber include:

[0051] Under stirring, the weighed hydroxyl silicone oil is slowly added to a disperser containing QS-20 silica and dispersed for 30 minutes to mix evenly. The treated silica and the weighed aluminum-doped modified polyhedral oligomeric silsesquioxane are added in batches to a kneader containing vinyl-terminated polydimethylsiloxane and vinyl-terminated polydimethyl-methylvinylsiloxane. Under N2 conditions, the mixture is kneaded while the temperature is raised to 140°C. The mixture is kneaded for 5 hours and then cooled for 12 hours to obtain the first-component rubber compound.

[0052] The primary compound, hydroxyl silicone oil (structural control agent, viscosity 50CS, hydroxyl content 8%), and zinc stearate are placed in a kneader and kneaded at below 80°C for 1 hour for a secondary compounding to obtain the secondary compound.

[0053] The vulcanization process includes:

[0054] Weigh out 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (bis-2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane) and add it to the secondary compound for mixing. After mixing evenly, place it in a mold and vulcanize at 160°C for 10 min under a pressure of 13 MPa and then at 200°C for 4 h. Remove it and place it in a vacuum drying oven to cool to room temperature to obtain low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties.

[0055] Example 3

[0056] This embodiment provides a method for preparing low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties. The difference from Embodiment 1 is that the type of metal-doped modified polyhedral oligomeric silsesquioxane is adjusted, including the preparation steps of the metal-doped modified polyhedral oligomeric silsesquioxane, the raw material weighing step, the preparation step of the compound, and the vulcanization step.

[0057] The preparation steps of metal-doped modified polyhedral oligomeric silsesquioxanes include:

[0058] Weigh trisilyl phenyl POSS and TiCl3(NMe)2 at a molar ratio of 1:1.05. Dissolve the weighed trisilyl phenyl POSS in toluene solution under a nitrogen atmosphere, then add the weighed TiCl3(NMe)2 and stir to dissolve. Continue to purge under a N2 atmosphere for 30 min to remove air and moisture. Place the solution in a preheated environment at 80℃ for 16 h to remove the solvent, wash with methanol, and vacuum dry for 12 h to obtain titanium-doped modified polyhedral oligomeric silsesquioxane.

[0059] The steps for weighing raw materials include:

[0060] According to the mass ratio of 50:5:1.2:40:4:1:0.01:2, the following raw materials were weighed as raw materials for vulcanized silicone rubber: vinyl-terminated polydimethylsiloxane (vinyl content 0.05%, molecular weight 600,000), vinyl-terminated polydimethyl-methylvinylsiloxane (vinyl content 0.8%, molecular weight 450,000), 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (bis-25), QS-20 silica, hydroxyl silicone oil, hydroxyl silicone oil (structure control agent, viscosity 50CS, hydroxyl content 8%), zinc stearate, and titanium-doped modified polyhedral oligomeric silsesquioxane.

[0061] The preparation steps of the compound rubber include:

[0062] Under stirring, the weighed hydroxyl silicone oil is slowly added to a disperser containing QS-20 silica and dispersed for 30 minutes to mix evenly. The treated silica and the weighed titanium-doped modified polyhedral oligomeric silsesquioxane are added in batches to a kneader containing vinyl-terminated polydimethylsiloxane and vinyl-terminated polydimethyl-methylvinylsiloxane. Under N2 conditions, the mixture is kneaded while the temperature is raised to 140°C. The mixture is kneaded for 5 hours and then cooled for 12 hours to obtain the first-component rubber compound.

[0063] The primary compound, hydroxyl silicone oil (structural control agent, viscosity 50CS, hydroxyl content 8%), and zinc stearate are placed in a kneader and kneaded at below 80°C for 1 hour for a secondary compounding to obtain the secondary compound.

[0064] The vulcanization process includes:

[0065] Weigh out 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (bis-2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane) and add it to the secondary compound for mixing. After mixing evenly, place it in a mold and vulcanize at 160°C for 10 min under a pressure of 13 MPa and then at 200°C for 4 h. Remove it and place it in a vacuum drying oven to cool to room temperature to obtain low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties.

[0066] Example 4

[0067] This embodiment provides a method for preparing low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties. The difference from Embodiment 1 is that the amount of various raw materials and the type of vulcanizing agent of the vulcanized silicone rubber are adjusted, including the preparation steps of metal-doped modified polyhedral oligomeric silsesquioxane, the raw material weighing step, the preparation step of the compound, and the vulcanization step.

[0068] The preparation steps of metal-doped modified polyhedral oligomeric silsesquioxanes include:

[0069] Weigh trisilyl isobutyl ester (POSS) and AlCl3 at a molar ratio of 1:1.05. Under a nitrogen atmosphere, dissolve the weighed POSS in a mixture of triethylamine and toluene, then add the weighed AlCl3 and stir to dissolve. Continue to purge under a N2 atmosphere for 30 min to remove air and moisture. Place the solution in a preheated environment at 60 °C for 24 h to remove the solvent, wash with methanol, and vacuum dry for 12 h to obtain aluminum-doped modified polyhedral oligomeric silsesquioxane.

[0070] The steps for weighing raw materials include:

[0071] According to the mass ratio of 55:6:35:4:0.8:0.01:5, the following raw materials were weighed: vinyl-terminated polydimethylsiloxane (vinyl content 0.05%, molecular weight 600,000), vinyl-terminated polydimethyl-methylvinylsiloxane (vinyl content 0.8%, molecular weight 450,000), QS-20 silica, hydroxyl silicone oil, hydroxyl silicone oil (structure control agent, viscosity 50CS, hydroxyl content 8%), zinc stearate, and aluminum-doped modified polyhedral oligomeric silsesquioxane as raw materials for vulcanized silicone rubber. 85 ppm of platinum(0)-1,3-diethylene-1,1,3,3-tetramethyldisiloxane was weighed as a vulcanizing agent.

[0072] The preparation steps of the compound rubber include:

[0073] Under stirring, the weighed hydroxyl silicone oil is slowly added to a disperser containing QS-20 silica and dispersed for 30 minutes to mix evenly. The treated silica and the weighed aluminum-doped modified polyhedral oligomeric silsesquioxane are added in batches to a kneader containing vinyl-terminated polydimethylsiloxane and vinyl-terminated polydimethyl-methylvinylsiloxane. Under N2 conditions, the mixture is kneaded while the temperature is raised to 140°C. The mixture is kneaded for 5 hours and then cooled for 12 hours to obtain the first-component rubber compound.

[0074] The primary compound, hydroxyl silicone oil (structural control agent, viscosity 50CS, hydroxyl content 8%), and zinc stearate are placed in a kneader and kneaded at below 80°C for 1 hour for a secondary compounding to obtain the secondary compound.

[0075] The vulcanization process includes:

[0076] The weighed platinum(O)-1,3-diethylene-1,1,3,3-tetramethyldisiloxane was added to the secondary compound and mixed evenly. The mixture was then placed in a mold and vulcanized at 160°C for 10 min under a pressure of 13 MPa, followed by vulcanization at 200°C for 4 h. The mixture was then removed and placed in a vacuum drying oven to cool to room temperature, resulting in a low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties.

[0077] Example 5

[0078] This embodiment provides a method for preparing low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties. The difference from Embodiment 1 is that the amounts of various raw materials for vulcanized silicone rubber and the types of metal-doped modified polyhedral oligomeric silsesquioxane, silica modifier, and structure control agent are adjusted. This includes the preparation steps of metal-doped modified polyhedral oligomeric silsesquioxane, the raw material weighing step, the preparation step of the compound, and the vulcanization step.

[0079] The preparation steps of metal-doped modified polyhedral oligomeric silsesquioxanes include:

[0080] Weigh trisilyl phenyl POSS and TiCl3(NMe)2 at a molar ratio of 1:1.05. Dissolve the weighed trisilyl phenyl POSS in toluene solution under a nitrogen atmosphere, then add the weighed TiCl3(NMe)2 and stir to dissolve. Continue to purge under a N2 atmosphere for 30 min to remove air and moisture. Place the solution in a preheated environment at 80℃ for 16 h to remove the solvent, wash with methanol, and vacuum dry for 12 h to obtain titanium-doped modified polyhedral oligomeric silsesquioxane.

[0081] The steps for weighing raw materials include:

[0082] According to the mass ratio of 55:6:1.2:35:3:0.5:0.01:2, the following raw materials were weighed: vinyl-terminated polydimethylsiloxane (vinyl content 0.05%, molecular weight 600,000), vinyl-terminated polydimethyl-methylvinylsiloxane (vinyl content 0.8%, molecular weight 450,000), 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (bis-dipentane), QS-20 silica, hexamethyldisilazane, trimethylsilanol, zinc stearate, and titanium-doped modified polyhedral oligomeric silsesquioxane as raw materials for vulcanized silicone rubber.

[0083] The preparation steps of the compound rubber include:

[0084] Under stirring, the weighed hexamethyldisilazane was slowly added to a disperser containing QS-20 silica and dispersed for 30 minutes to mix evenly. The treated silica and the weighed titanium-doped modified polyhedral oligomeric silsesquioxane were added in batches to a kneader containing vinyl-terminated polydimethylsiloxane and vinyl-terminated polydimethyl-methylvinylsiloxane. Under N2 conditions, the mixture was kneaded and heated to 140°C. The mixture was kneaded for 5 hours and then cooled for 12 hours to obtain the first-component rubber compound.

[0085] The primary compound, trimethylsilyl alcohol, and zinc stearate are placed in a kneader and kneaded at below 80°C for 1 hour for a secondary compounding process to obtain the secondary compound.

[0086] The vulcanization process includes:

[0087] Weigh out 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (bis-2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane) and add it to the secondary compound for mixing. After mixing evenly, place it in a mold and vulcanize at 160°C for 10 min under a pressure of 13 MPa and then at 200°C for 4 h. Remove it and place it in a vacuum drying oven to cool to room temperature to obtain low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties.

[0088] Comparative Example 1

[0089] This comparative example provides a method for preparing vulcanized silicone rubber, including the steps of weighing raw materials, preparing the compound, and vulcanization.

[0090] The steps for weighing raw materials include:

[0091] According to the mass ratio of 50:5:1.2:40:4:1:0.01, the following raw materials were weighed as raw materials for vulcanized silicone rubber: vinyl-terminated polydimethylsiloxane (vinyl content 0.05%, molecular weight 600,000), vinyl-terminated polydimethyl-methylvinylsiloxane (vinyl content 0.8%, molecular weight 450,000), 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (bis-25), QS-20 silica, hydroxyl silicone oil, hydroxyl silicone oil (structural control agent, viscosity 50CS, hydroxyl content 8%), and zinc stearate.

[0092] The preparation steps of the compound rubber include:

[0093] Under stirring, the weighed hydroxyl silicone oil is slowly added to a disperser containing QS-20 silica and dispersed for 30 minutes to mix evenly. The treated silica is then added in batches to a kneader containing vinyl-terminated polydimethylsiloxane and vinyl-terminated polydimethyl-methylvinylsiloxane. Under N2 conditions, the mixture is kneaded while the temperature is raised to 140°C. The mixture is kneaded for 5 hours at a time and then cooled for 12 hours to obtain the first-component rubber compound.

[0094] The primary compound, hydroxyl silicone oil (structural control agent, viscosity 50CS, hydroxyl content 8%), and zinc stearate are placed in a kneader and kneaded at below 80°C for 1 hour for a secondary compounding to obtain the secondary compound.

[0095] The vulcanization process includes:

[0096] Weigh out 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (bis25) and add it to the secondary compound for mixing. After mixing evenly, place it in a mold and vulcanize at 160°C for 10 min under a pressure of 13 MPa, then vulcanize at 200°C for 4 h. Remove it and place it in a vacuum drying oven to cool to room temperature to obtain vulcanized silicone rubber.

[0097] Comparative Example 2

[0098] This comparative example provides a method for preparing vulcanized silicone rubber, including the steps of weighing raw materials, preparing the compound, and vulcanization.

[0099] The steps for weighing raw materials include:

[0100] According to the mass ratio of 55:6:35:4:0.8:0.01, vinyl-terminated polydimethylsiloxane (vinyl content 0.05%, molecular weight 600,000), vinyl-terminated polydimethyl-methylvinylsiloxane (vinyl content 0.8%, molecular weight 450,000), QS-20 silica, hydroxyl silicone oil, hydroxyl silicone oil (structural control agent, viscosity 50CS, hydroxyl content 8%), and zinc stearate were weighed as raw materials for vulcanized silicone rubber, and 85 ppm of platinum(0)-1,3-diethylene-1,1,3,3-tetramethyldisiloxane was weighed as vulcanizing agent.

[0101] The preparation steps of the compound rubber include:

[0102] Under stirring, the weighed hydroxyl silicone oil is slowly added to a disperser containing QS-20 silica and dispersed for 30 minutes to mix evenly. The treated silica is then added in batches to a kneader containing vinyl-terminated polydimethylsiloxane and vinyl-terminated polydimethyl-methylvinylsiloxane. Under N2 conditions, the mixture is kneaded while the temperature is raised to 140°C. The mixture is kneaded for 5 hours at a time and then cooled for 12 hours to obtain the first-component rubber compound.

[0103] The primary compound, hydroxyl silicone oil (structural control agent, viscosity 50CS, hydroxyl content 8%), and zinc stearate are placed in a kneader and kneaded at below 80°C for 1 hour for a secondary compounding to obtain the secondary compound.

[0104] The vulcanization process includes:

[0105] The weighed platinum(O)-1,3-diethylene-1,1,3,3-tetramethyldisiloxane was added to the secondary compound and mixed evenly. The mixture was then placed in a mold and vulcanized at 160°C for 10 minutes under a pressure of 13 MPa, followed by vulcanization at 200°C for 4 hours. The mixture was then removed and placed in a vacuum drying oven to cool to room temperature to obtain vulcanized silicone rubber.

[0106] Comparative Example 3

[0107] This comparative example provides a method for preparing electromagnetically shielded vulcanized silicone rubber, including steps of weighing raw materials, preparing the compound, and vulcanization.

[0108] The steps for weighing raw materials include:

[0109] Weigh the following ingredients according to a mass ratio of 50:5:1.2:40:4:1:0.01:2: vinyl-terminated polydimethylsiloxane (vinyl content 0.05%, molecular weight 600,000), vinyl-terminated polydimethyl-methylvinylsiloxane (vinyl content 0.8%, molecular weight 450,000), 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (bis(di-pentane)), QS-20 silica, hydroxyl silicone oil, hydroxyl silicone oil (structure control agent, viscosity 50 CS, hydroxyl content 8%), zinc stearate, and nano titanium dioxide (99%, particle size 20 nm, specific surface area 120 m²). 2 / g) is used as a raw material for vulcanized silicone rubber.

[0110] The preparation steps of the compound rubber include:

[0111] Under stirring, the weighed hydroxyl silicone oil is slowly added to a disperser containing QS-20 silica and dispersed for 30 minutes to mix evenly. The treated silica and the weighed nano titanium dioxide are added in batches to a kneader containing vinyl-terminated polydimethylsiloxane and vinyl-terminated polydimethyl-methylvinylsiloxane. Under N2 conditions, the mixture is kneaded and heated to 140°C. The mixture is kneaded for 5 hours at a time and then cooled for 12 hours to obtain the first-component rubber compound.

[0112] The primary compound, hydroxyl silicone oil (structural control agent, viscosity 50CS, hydroxyl content 8%), and zinc stearate are placed in a kneader and kneaded at below 80°C for 1 hour for a secondary compounding to obtain the secondary compound.

[0113] The vulcanization process includes:

[0114] Weigh out 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (bis-2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane) and add it to the secondary compound for mixing. After mixing evenly, place it in a mold and vulcanize at 160°C for 10 min under a pressure of 13 MPa and at 200°C for 4 h. Remove it and place it in a vacuum drying oven to cool to room temperature to obtain electromagnetic shielding vulcanized silicone rubber.

[0115] Comparative Example 4

[0116] This comparative example provides a method for preparing electromagnetically shielded vulcanized silicone rubber, including steps of weighing raw materials, preparing the compound, and vulcanization.

[0117] The steps for weighing raw materials include:

[0118] Weigh the following components according to a mass ratio of 50:5:1.2:40:4:1:0.01:2: vinyl-terminated polydimethylsiloxane (vinyl content 0.05%, molecular weight 600,000), vinyl-terminated polydimethyl-methylvinylsiloxane (vinyl content 0.8%, molecular weight 450,000), 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (bis(dimethyl)hexane), QS-20 silica, hydroxyl silicone oil, hydroxyl silicone oil (structure control agent, viscosity 50 CS, hydroxyl content 8%), zinc stearate, and conductive carbon black (98%, particle size 40~48 nm, specific surface area 125 m²). 2 / g) is used as a raw material for vulcanized silicone rubber.

[0119] The preparation steps of the compound rubber include:

[0120] Under stirring, the weighed hydroxyl silicone oil is slowly added to a disperser containing QS-20 silica and dispersed for 30 minutes to mix evenly. The treated silica and the weighed conductive carbon black are added in batches to a kneader containing vinyl-terminated polydimethylsiloxane and vinyl-terminated polydimethyl-methylvinylsiloxane. Under N2 conditions, the mixture is kneaded and heated to 140°C. The mixture is kneaded for 5 hours at a time and then cooled for 12 hours to obtain the first-component rubber compound.

[0121] The primary compound, hydroxyl silicone oil (structural control agent, viscosity 50CS, hydroxyl content 8%), and zinc stearate are placed in a kneader and kneaded at below 80°C for 1 hour for a secondary compounding to obtain the secondary compound.

[0122] The vulcanization process includes:

[0123] Weigh out 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (bis-2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane) and add it to the secondary compound for mixing. After mixing evenly, place it in a mold and vulcanize at 160°C for 10 min under a pressure of 13 MPa and at 200°C for 4 h. Remove it and place it in a vacuum drying oven to cool to room temperature to obtain electromagnetic shielding vulcanized silicone rubber.

[0124] Experimental Example 1

[0125] This experimental example tests the performance of the vulcanized silicone rubbers provided in Examples 1-5 and Comparative Examples 1-4. The performance tests include mechanical properties, electromagnetic shielding properties, and volatility tests, specifically including the following steps:

[0126] The vulcanized silicone rubbers provided in Examples 1-5 and Comparative Examples 1-4 were tested for tensile strength and elongation at break according to GB / T 528-2008 "Determination of Tensile Stress-Strain Properties of Vulcanized Rubber or Thermoplastic Rubber"; for tear strength according to GB / T 529-2008 "Test of Tear Strength of Vulcanized Rubber or Thermoplastic Rubber"; and for electromagnetic shielding effectiveness according to GJB 6190-2008 "Method for Measuring Shielding Effectiveness of Electromagnetic Shielding Materials" (sample thickness was 1 mm). Volatility was tested according to Appendix B of GB4806.16-2025 "National Food Safety Standard - Determination of Volatile Substances in Silicone Rubber Materials and Products for Food Contact". The test results are shown in Table 1.

[0127] Table 1: Performance Test Results of Vulcanized Silicone Rubber

[0128]

[0129] As shown in Table 1, compared with the vulcanized silicone rubber provided in Comparative Examples 1-2, the vulcanized silicone rubber provided in Examples 1-5 exhibits significantly improved electromagnetic shielding performance to 68-82 dB, increased tensile strength to 8.2-9.3 MPa, improved tear strength to 26.23-32.7 KN / m, and elongation at break reaching 730-895%. Furthermore, the volatile components of cyclosiloxanes such as D4, D4, and D6 after the second stage are significantly reduced. This indicates that the introduction of metal-doped modified polyhedral oligomeric silsesquioxanes into the vulcanized silicone rubber, with the general formula T8R7R′, where R groups are hydroxyl, methyl, phenyl, vinyl, carboxyl, isobutyl, allyl, or alkoxy groups, demonstrates the effectiveness of this method. The R′ group is doped with at least one metal selected from Al, Ti, Fe, and Ni. On the one hand, the metal doping in the R′ group imparts excellent electromagnetic shielding performance to the vulcanized silicone rubber. On the other hand, as an organic group, the R group has good compatibility with the vulcanized silicone rubber and few interface defects. At the same time, the active sites of some R groups can increase the degree of crosslinking of the silicone rubber vulcanization crosslinking system, play a mechanical reinforcing role, and reduce the residue of cyclosiloxanes such as D4, D4, and D6, thereby reducing volatility. Thus, Examples 1-5 of this application provide vulcanized silicone rubber with excellent electromagnetic shielding performance, mechanical properties, and low volatility, overcoming the defects of poor comprehensive performance of traditional vulcanized silicone rubber.

[0130] Meanwhile, as can be seen from Table 1, the overall performance of the silicone rubber provided in Comparative Examples 3-4 is also lower than that of the silicone rubber provided in Examples 1-5. This is because, although nano-titanium dioxide or conductive carbon black was introduced into the silicone rubber provided in Comparative Examples 3-4 to improve the electromagnetic shielding performance of the silicone rubber, the nano-titanium dioxide or conductive carbon black, as inorganic fillers, is difficult to be compatible with the silicone rubber, has poor uniform dispersion and stability, and is prone to agglomeration and interface defects, resulting in poor mechanical properties. The cyclosiloxane is also prone to volatilization, thus resulting in an overall performance lower than that of the silicone rubber provided in Examples 1-5.

[0131] In addition, as can be seen from Table 1, the vulcanized silicone rubber provided in Examples 1-5 can further optimize its mechanical properties, electromagnetic shielding properties, and volatility by adjusting the amount and type of components such as metal-doped modified polyhedral oligomeric silsesquioxanes.

[0132] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties, characterized in that, include: Organosilicon raw rubber, vulcanizing agent, inorganic reinforcing filler, surface treatment agent, structure control agent, release agent, and metal-doped modified polyhedral oligomeric silsesquioxane; The organosilicon raw rubber includes: a first organosilicon raw rubber and a second organosilicon raw rubber, wherein the vinyl content of the first organosilicon raw rubber is less than that of the second organosilicon raw rubber, and the molecular weight is greater than that of the second organosilicon raw rubber.

2. The low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties according to claim 1, characterized in that, The metal-doped modified polyhedral oligomeric silsesquioxane is selected from at least one metal-doped modified polyhedral oligomeric silsesquioxane from Al, Ti, Ni, and Fe.

3. The low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties according to claim 1, characterized in that, The organosilicon raw rubber is selected from at least two of the following: vinyl-terminated polydimethylsiloxane, vinyl-terminated polydimethyl-methylvinylsiloxane, polydimethyl-methylvinylsiloxane, vinyl-terminated polymethylphenylsiloxane, dimethylvinyl-terminated polydimethylsiloxane, dimethylvinyl-terminated polydimethyl-methylvinylsiloxane, methyl-terminated polymethylvinylsiloxane, polydimethylsiloxane, and hydroxyl-terminated polymethylvinylsiloxane. The vulcanizing agent is selected from at least one of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (bis-2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane), 2,4-dichlorobenzoyl peroxide, platinum catalyst combined with hydrogen-containing silicone oil, bis-(2,4-dichlorobenzoyl peroxide), benzoyl peroxide, and dicumyl peroxide.

4. The low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties according to claim 1, characterized in that, The organosilicon raw rubber comprises: a first organosilicon raw rubber with a vinyl content of 0.01% to 0.05% and a molecular weight of 500,000 to 700,000, and a second organosilicon raw rubber with a vinyl content of 1% to 5% and a molecular weight of 400,000 to 550,000.

5. The low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties according to claim 1, characterized in that, The inorganic reinforcing filler is selected from at least one of fumed silica, nano-calcium carbonate, and silica powder. The surface treatment agent is selected from at least one of the following: hydroxyl-terminated polydimethylsiloxane, hexamethyldisilazane, vinylsilazane, vinyl hydroxyl-terminated polydimethylsiloxane, dimethyldimethoxysilane, dimethyldiethoxysilane, methyltrimethoxysilane, vinyltriethoxysilane, glycidylpropyltrimethoxysilane, methacrylate-propyltrimethoxysilane, and octamethylcyclotetrasiloxane. The structuring control agent is selected from at least one of the following: oligosiloxanes containing hydroxyl or alkoxy groups, alkylsilanols, phenylsilanols, diol compounds, silanes containing hydroxyl or alkoxy groups, and hydroxyl-terminated polymethylvinylsiloxanes. The release agent is selected from at least one of stearic acid, zinc stearate, calcium stearate, barium stearate, magnesium stearate, zinc laurate, magnesium laurate, palmitic acid, and lauric acid.

6. The low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties according to claim 1, characterized in that, Based on parts by weight, the low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties comprises: 40-60 parts by weight of a first organosilicon raw rubber, 4-10 parts by weight of a second organosilicon raw rubber, 0.5-1.5 parts by weight of a vulcanizing agent, 35-45 parts by weight of an inorganic reinforcing filler, 2-5 parts by weight of a surface treatment agent, 0.5-1.5 parts by weight of a structuring control agent, 0.005-0.02 parts by weight of a release agent, and 1-10 parts by weight of a metal-doped modified polyhedral oligomeric silsesquioxane.

7. A method for preparing low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties, characterized in that, The preparation of a low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties as described in any one of claims 1-6 includes the following steps: By reacting POSS containing reactive groups with a metal source, metal-doped modified polyhedral oligomeric silsesquioxanes are obtained. Inorganic reinforcing filler, surface treatment agent, and metal-doped modified polyhedral oligomeric silsesquioxane are added to the first organosilicon raw rubber and the second organosilicon raw rubber for a first compounding process to obtain a first compound. The structure control agent and the release agent are added to the primary compound and then mixed again to obtain the secondary compound. The vulcanizing agent is added to the secondary compound and subjected to open milling and vulcanization to obtain low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties.

8. The method for preparing a low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties according to claim 7, characterized in that, The reaction of POSS containing reactive groups and a metal source includes: dispersing trisilyl isobutyl ester POSS or trisilyl phenyl POSS and a metal source in an organic solvent under nitrogen and anhydrous conditions to obtain metal-doped modified polyhedral oligomeric silsesquioxane.

9. The method for preparing a low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties according to claim 7, characterized in that, The temperature of the first mixing is 130~150℃ and the time is 1~5h; the temperature of the second mixing is 70~90℃ and the time is 0.5~2h. The vulcanization process includes: vulcanization at 150-180℃ for 5-20 minutes under a pressure of 10-15 MPa. Vulcanize at 180~220℃ for 1~4 hours.

10. The application of a low-volatility electromagnetic shielding vulcanized silicone rubber with excellent mechanical properties as described in any one of claims 1-6 in the fields of 5G communication, new energy or artificial intelligence.

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