A high resilience silicone rubber and a method for preparing the same

Abstract

The application provides a high-resilience silicone rubber and a preparation method thereof, which comprises the following components in parts by weight: 100 parts of methyl vinyl silicone rubber, 30-40 parts of fumed white carbon black, 3-7 parts of methoxysilicone oil, 0.5-1.5 parts of hydroxysilicone oil, 0.3-0.6 parts of vinyl hydroxysilicone oil, 0.1-0.2 parts of stearic acid, 0.5-2.0 parts of a vulcanizing agent, 0.2-1.0 parts of a resilience enhancer, and 0.1-1.0 parts of methyl trialkoxysilane; the resilience enhancer is obtained by hydrosilation reaction of triallyl isocyanurate and methyl hydrogen siloxane. The high-resilience silicone rubber prepared by the application can release the deformation energy more quickly and has strong resilience after being compressed, bent or deformed for a short time.

Description

Technical Field

[0001] This application relates to the field of vulcanized silicone rubber technology, specifically to a high-resilience silicone rubber and its preparation method. Background Technology

[0002] Silicone rubber is a synthetic elastomer with a main chain composed of alternating silicon and oxygen atoms and side chains linked to organic groups. Based on vulcanization temperature, it is classified into two categories: high-temperature vulcanized and room-temperature vulcanized. High-temperature vulcanized types include methyl silicone rubber, methyl vinyl silicone rubber (the most widely used), methyl vinyl phenyl silicone rubber, as well as special types such as fluorosilicone rubber and nitrile silicone rubber. Room-temperature vulcanized types are further divided into condensation reaction type and addition reaction type, mainly used in adhesives and potting materials. Silicone rubber can maintain its working performance at -55℃, and with the introduction of phenyl groups, its low-temperature resistance can reach -73℃, and its long-term heat resistance temperature reaches 180℃ (short-term resistance to 300℃). Its outstanding characteristics include excellent air permeability (the highest oxygen permeability among synthetic polymers), physiological inertness, and electrical properties, making it widely used in medical implants, new energy vehicle battery seals, and aerospace vibration damping materials.

[0003] Methyl vinyl silicone rubber has a low Si-O-Si bond rotation energy barrier in its main chain, making it prone to molecular chain slippage and rearrangement under stress, resulting in insufficient chain recovery motive force after stress removal. Fumed silica, as a reinforcing filler, is rich in silanol groups on its surface. After dispersion, it mainly bonds with the silicone rubber matrix through physical interactions such as hydrogen bonding. During dynamic compression, micro-slippage occurs at the filler-matrix interface, leading to irreversible accumulation of deformation under stress and significantly reducing resilience. To address this issue, existing technologies attempt to introduce coupling agents at the interface or enhance network rigidity by increasing crosslinking density. However, coupling agents can only anchor the filler and have limited ability to inhibit slippage of the matrix chain segments themselves; excessive crosslinking can make the network brittle, thus reducing resilience.

[0004] Therefore, how to improve the resilience of methyl vinyl silicone rubber remains a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] This application provides a high-resilience silicone rubber and its preparation method. The high-resilience silicone rubber prepared by adding a resilience enhancer and methyltrialkoxysilane can release the deformation energy more quickly after being subjected to pressure, bending or short-term deformation, and has strong resilience.

[0006] In a first aspect, this application provides a high-resilience silicone rubber comprising the following parts by weight of raw materials: 100 parts methyl vinyl silicone rubber, 30-40 parts fumed silica, 3-7 parts methoxy silicone oil, 0.5-1.5 parts hydroxy silicone oil, 0.3-0.6 parts vinyl hydroxy silicone oil, 0.1-0.2 parts stearic acid, 0.5-1.5 parts vulcanizing agent, 0.2-1.0 parts resilience enhancer, and 0.1-1.0 parts methyltrialkoxysilane; wherein the resilience enhancer is obtained by hydrosilylation reaction of triallyl isocyanurate and methylhydrosiloxane.

[0007] According to this application, methyl vinyl silicone rubber serves as the matrix material, providing the basic mechanical properties and elastic skeleton of silicone rubber; fumed silica serves as a reinforcing filler, which, through its high specific surface area and surface silanol groups, interacts with the silicone rubber matrix to improve the tensile strength, tear strength, and abrasion resistance of the material; methoxy silicone oil, hydroxyl silicone oil, and vinyl hydroxyl silicone oil serve as structure control agents, which, through their active groups, interact with the silanol groups on the surface of fumed silica, inhibit hydrogen bond aggregation between fumed silica particles and improve the uniformity of filler dispersion in the silicone rubber matrix. The vinyl groups in the vinyl hydroxyl silicone oil can also participate in cross-linking reactions during vulcanization, enhancing the filler-matrix interface bonding; stearic acid serves as a processing aid, reducing the adhesion of the rubber compound to metal equipment during mixing and improving processing fluidity and mold release properties; the vulcanizing agent decomposes under heating conditions to generate free radicals, initiating cross-linking reactions between silicone rubber molecular chains to form a three-dimensional network structure, endowing the material with stable elastomer properties.

[0008] The core improvement of this application does not lie in simply adding a crosslinking aid or an interface treatment agent, but in simultaneously introducing methyltrialkoxysilane and a resilience enhancer to achieve control over the crosslinking network between the silica interface and silicone rubber. The resilience enhancer is a polyvinyl isocyanurate derivative prepared by platinum-catalyzed hydrosilylation of triallyl isocyanurate and methylhydrosiloxane. Its molecule has a rigid isocyanurate ring as its core, while also retaining some allyl groups. This structure endows the resilience enhancer with three characteristics: First, the isocyanurate rigid ring can form discrete rigid recovery nodes in the vulcanization network for stress transfer and elastic energy storage; second, it retains some allyl groups that can participate in free radical crosslinking during peroxide vulcanization, allowing the rigid nodes to be covalently embedded in the silicone rubber network; third, the resilience enhancer molecule does not contain functional groups such as silanol (-SiOH), alkoxysilane (-SiOR), and aminosilane (-SiNH2) that can undergo condensation reactions with silanol groups on the surface of silica, so it mainly participates in network construction and does not preferentially consume the active sites on the surface of silica.

[0009] The alkoxy group in the methyltrialkoxysilane molecule can hydrolyze to generate a silanol group in the presence of trace amounts of water, which further undergoes a condensation reaction with some silanol groups on the surface of silica, forming a methyl-containing organosilicon layer on the silica surface. This treatment reduces the excessively strong hydrogen bonding between silica particles and between silica and the silicone rubber matrix, as well as the degree of filler structuring, thus reducing interfacial friction. Furthermore, it selectively occupies and regulates the active sites on the silica surface, making it less likely for subsequently added resilience enhancers to couple with the filler interface, instead allowing them to be mainly distributed within the silicone rubber network.

[0010] During the research process, this application found that in existing high-resilience silicone rubber systems, methods such as increasing the degree of crosslinking, adding multifunctional crosslinking agents, or enhancing the effect of fillers are commonly used to improve resilience and deformation recovery. However, these methods often increase the local modulus of the rubber compound, strengthen the structure of the fillers, and exacerbate stress concentration while improving resilience. This leads to problems such as a harder feel, decreased elongation at break, whitening during bending, or uneven recovery of compression deformation in the finished product. Further analysis revealed that in silica-filled silicone rubber systems, the residual silanol groups on the silica surface are not only an important source of reinforcement but also a key factor leading to strong filler-filler interactions and increased interfacial friction. If reactive and rigid network reinforcement components are directly incorporated into the system, although the network recovery ability can be improved to some extent, its effect is easily constrained by the interfacial friction and local stress concentration of silica, preventing the reinforcement effect from being fully converted into macroscopic resilience performance and potentially amplifying side effects such as material hardening and decreased elongation. To address the aforementioned issues, this application proposes a technical approach of first adjusting the interface and then adjusting the network: First, the surface of silica is pretreated with methyltrialkoxysilane to preferentially reduce the excessive structuring effect and interfacial energy dissipation on the silica surface, thereby alleviating local stress concentration at the filler interface. Then, a resilience enhancer without functional groups capable of condensing with the silanol groups on the silica surface is introduced, allowing it to primarily participate in the formation of the silicone rubber network during the peroxide curing stage, constructing discrete, high-resilience rigid nodes within the network. Thus, methyltrialkoxysilane not only improves the filler interface but also provides a low-loss, low-stress-concentration structural environment for the effective functioning of the resilience enhancer within the network. The resilience enhancer not only simply enhances network recovery but also further transforms the low internal friction state brought about by methyltrialkoxysilane into higher resilience performance and better compression recovery. Through this synergistic cooperation between the target and the stage of action, disorderly competition for active sites on the silica surface by different modifying components is avoided, as is structural runaway caused by premature intervention of rigid reinforcing components in filler mixing.

[0011] Through the synergy of the aforementioned structural and process designs, this application does not simply achieve high resilience by increasing hardness or crosslinking density. Instead, it leverages the high-recovery rigidity nodes formed by the resilience enhancer in the network to improve the storage and release efficiency of the silicone rubber for deformation energy. This is achieved by using methyltrialkoxysilane to reduce energy dissipation at the filler interface and mitigate the localized hardening and stress concentration tendencies that occur when the resilience enhancer is used alone. Therefore, the resulting silicone rubber can further improve resilience, reduce compression set, and improve crease recovery speed while maintaining good feel, high elongation, and moderate hardness, thus achieving a synergistic improvement in resilience, recovery performance, and mechanical properties.

[0012] In some embodiments, the methyltrialkoxysilane includes at least one of methyltrimethoxysilane and methyltriethoxysilane.

[0013] In some of the aforementioned methods, methyltrimethoxysilane and methyltriethoxysilane both belong to the methyltrialkoxysilane family and share common chemical characteristics: the molecule contains one methyl hydrophobic group and three hydrolyzable alkoxy groups (methoxy or ethoxy). In the presence of trace amounts of water, the alkoxy groups hydrolyze to generate silanol groups (-SiOH), which undergo a condensation reaction with the silanol groups on the surface of silica to form stable Si-O-Si covalent bonds, thereby introducing a methyl hydrophobic layer onto the filler surface. This synergistic mechanism offers the following advantages: First, methyltrialkoxysilane preferentially reacts with the silica surface before the resilience enhancer, occupying active sites and effectively inhibiting the anchoring of the subsequently added resilience enhancer to the filler surface due to the presence of condensation groups. This forces the resilience enhancer to enter the silicone rubber network and act as a rigid node. Second, the methyl hydrophobic layer formed after grafting reduces the hydrogen bonding interactions between silica particles, decreasing internal friction and energy dissipation in the filler network, thus reducing the sliding resistance of the molecular chains during dynamic deformation. Finally, a moderately flexible interface layer is formed between the silica surface treated with methyltrialkoxysilane and the silicone rubber matrix, avoiding stress concentration caused by excessive interfacial bonding and preventing interfacial debonding caused by excessive hydrophobicity.

[0014] In some embodiments, the method for preparing the resilience enhancer includes the following steps: 30 parts of triallyl isocyanurate were added to 300-600 parts of anhydrous toluene and stirred to dissolve under nitrogen protection. Then, 25-30 parts of methylhydrosiloxane were added. Under the action of a platinum catalyst and at 60-75°C, the Si-H bonds of the methylhydrosiloxane and some of the allyl double bonds in the triallyl isocyanurate underwent a platinum-catalyzed hydrosilylation addition reaction to obtain an isocyanurate derivative containing an isocyanurate ring, a heptamethyltrisiloxane propyl branch, and some allyl groups, which can be used as a resilience enhancer.

[0015] The amount of triallyl isocyanurate was limited to 30 parts, and the amount of methylhydrosiloxane was limited to 25-30 parts. This allowed the Si-H bonds in the methylhydrosiloxane to undergo a hydrosilylation addition reaction with some of the allyl double bonds in the triallyl isocyanurate, without consuming all the allyl groups in the triallyl isocyanurate. Thus, the resulting resilience enhancer, on the one hand, introduces heptamethyltrisiloxane propyl branches into the rigid ring structure of the isocyanurate, improving its structural compatibility and dispersion stability with the methyl vinyl silicone rubber matrix; on the other hand, it retains some of the allyl groups derived from the triallyl isocyanurate, enabling it to participate in free radical crosslinking during subsequent peroxide vulcanization and covalently embed into the silicone rubber crosslinking network.

[0016] By controlling the dosage as described above, the resilience enhancer is not only dispersed as a free small molecule in the silicone rubber system, but can also participate in network construction during the vulcanization stage; at the same time, the introduction of heptamethyltrisiloxane side chains avoids local agglomeration or stress concentration caused by insufficient compatibility of the rigid structure of isocyanurate.

[0017] In some implementations, the reaction time is 3 to 5 hours.

[0018] In some of the above methods, controlling the reaction time to 3-5 hours allows the Si-H bonds in methylhydrosiloxane to fully undergo hydrosilylation addition with some of the allyl double bonds in triallyl isocyanurate, effectively introducing the heptamethyltrisiloxane propyl branch into the isocyanurate structure. At the same time, this reaction time does not cause excessive consumption of allyl groups in triallyl isocyanurate, which is beneficial for retaining an appropriate amount of allyl groups in the resulting resilience enhancer as sites for subsequent vulcanization crosslinking.

[0019] In some embodiments, the vulcanizing agent is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane.

[0020] Among the methods mentioned above, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, as a vulcanizing agent, has a moderate decomposition temperature, and can stably generate free radicals at around 170℃. These free radicals initiate cross-linking reactions of the allyl groups in the silicone rubber matrix and the resilience enhancer, forming a stable three-dimensional network. The decomposition products of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane have low volatility, no odor, and are not prone to yellowing. They also exhibit good compatibility with methyltrialkoxysilane and the resilience enhancer.

[0021] In some embodiments, the specific surface area of ​​the fumed silica is 150~250 m². 2 / g.

[0022] In some of the methods mentioned above, the specific surface area is controlled between 150 and 250 m². 2Within the range of / g, it ensures that the silica fully reinforces the silicone rubber matrix while avoiding the structuralization of the filler network and the deterioration of resilience caused by excessively high specific surface area.

[0023] In some embodiments, the weight-average molecular weight of the methyl vinyl silicone rubber is 4.5 × 10⁻⁶. 5 ~6.5×10 5 The vinyl content is 0.05~0.15wt%.

[0024] In some of the above methods, within this molecular weight range, raw rubber has good processing fluidity and mixing dispersibility, and can be fully and uniformly mixed with components such as silica, resilience enhancer, and methyltrialkoxysilane. The crosslinked network formed after vulcanization is complete and has suitable strength, providing a stable network support for the rigid nodes provided by the resilience enhancer. Within this vinyl content range, raw rubber has an appropriate amount of crosslinking active sites, allowing the allyl groups of the resilience enhancer to fully participate in co-crosslinking, effectively embedding the rigid nodes into the network, while avoiding the decrease in elongation caused by excessive crosslinking density.

[0025] Secondly, this application provides a method for preparing high-resilience silicone rubber, comprising the following steps: S1. Provide a raw material for a high-resilience silicone rubber as described in any embodiment of the first aspect; S2. The methyltrialkoxysilane is mixed with a portion of fumed silica for pretreatment to obtain pretreated fumed silica; S3. The pretreated silica is mixed with the remaining fumed silica, methyl vinyl silicone rubber, methoxy silicone oil, hydroxy silicone oil, stearic acid and vinyl hydroxy silicone oil and then heat-treated to obtain the base compound; S4. Add a resilience enhancer and a vulcanizing agent to the base rubber compound and mix them together. After vulcanization molding, a high resilience silicone rubber product is obtained.

[0026] According to this application, a specific feeding sequence was used to achieve the separation and synergy of methyltrialkoxysilane and the resilience enhancer in terms of their target and action stage. First, methyltrialkoxysilane is pretreated with a portion of the fumed silica, allowing the methyltrialkoxysilane to preferentially act on the silica surface, forming a methyl-containing organosilicon layer on the filler surface. This reduces the strong hydrogen bonding between silica particles and the degree of filler structuring, thus reducing interfacial friction. The pretreated fumed silica is then added to the system along with the remaining fumed silica, which facilitates the uniform establishment of the interfacial regulation effect within the filler system. Second, the resilience enhancer is added after heat treatment to prevent it from prematurely participating in the filler interfacial interaction during the high-temperature mixing stage or being affected by the filler interface, thus avoiding uncontrolled dispersion and action positions. Because the resilience enhancer molecule does not contain functional groups that can undergo condensation reactions with the residual silanol groups on the surface of silica, and the silica surface has already been partially regulated by methyltrialkoxysilane, the resilience enhancer is mainly distributed in the silicone rubber matrix network. During the subsequent vulcanization stage, it participates in the crosslinking reaction through its terminal allyl groups, forming discrete high-recovery nodes with isocyanurate rigid rings as the core. Through a sequential process of interface regulation followed by network enhancement, methyltrialkoxysilane primarily reduces energy dissipation at the filler interface, while the resilience enhancer primarily improves the network recovery capability. This achieves a synergistic balance between low interface loss and high network recovery, ultimately resulting in silicone rubber that maintains good flexibility and moderate hardness while exhibiting higher resilience, lower compression set, and faster deformation recovery.

[0027] In some embodiments, a method for preparing a high-resilience silicone rubber includes the following steps: S1. Provide a raw material for a high-resilience silicone rubber as described in any embodiment of the first aspect; S2. Take 10~25wt% of fumed silica and add it to a high-speed mixer. Then add methyltrialkoxysilane and water, mix for 10~15min, then heat to 80~110℃ and keep warm for 20~45min to obtain pretreated silica. S3. Add methyl vinyl silicone rubber, methoxy silicone oil, hydroxy silicone oil, stearic acid and vinyl hydroxy silicone oil to a kneader and premix for 3-5 minutes. Then add the pretreated fumed silica and the remaining fumed silica to the kneader and mix for 30-60 minutes. Heat to 160-170°C and keep warm for 1.5-2.5 hours to obtain the base compound. S4. Add the rebound enhancer and the base rubber compound to the rubber mixing mill and mix for 3-8 minutes to disperse them evenly. Then add the vulcanizing agent and continue mixing for 2-5 minutes. Place the evenly mixed rubber compound in the vulcanizing mill and vulcanize at 165-175°C for 10-15 minutes to obtain the high-resilience silicone rubber product.

[0028] The above methods specifically illustrate the reaction conditions and dosage ratios of each step in the preparation of high-resilience silicone rubber. Under these conditions, high-resilience silicone rubber with good resilience properties can be obtained.

[0029] Thirdly, this application provides a high-resilience silicone rubber article, comprising high-resilience silicone rubber according to any embodiment of the first aspect or high-resilience silicone rubber prepared by the method according to any embodiment of the second aspect.

[0030] Compared with the prior art, the beneficial effects of this application are at least as follows: First, in this application, methyltrialkoxysilane is used to preferentially treat the surface of silica, forming a methyl-containing organosilicon layer on the filler surface. This reduces the strong hydrogen bonding between silica particles and the internal friction of the filler network, mitigating energy dissipation and local stress concentration in the interface region. This provides a more favorable structural environment for the subsequent rebound enhancer to function within the silicone rubber network. The subsequently added rebound enhancer participates in network formation during vulcanization, constructing high-recovery nodes centered on isocyanurate rigid rings. This allows the material to more effectively store and release elastic energy after deformation. Thus, the low-loss interface provided by methyltrialkoxysilane and the high-recovery network constructed by the rebound enhancer work synergistically, not only improving the material's rebound speed and rebound rate but also shortening crease recovery time and improving the feel of the product, thereby overcoming the problem of significant rebound hysteresis in conventional silicone rubber.

[0031] Secondly, the resilience enhancer described in this application mainly participates in vulcanization crosslinking through the partial allyl groups remaining from the reaction, forming discrete rigid recovery nodes within the silicone rubber network, rather than relying on chemical anchoring to the surface of silica. Methyltrialkoxysilane primarily moderately adjusts the silica surface, reducing the degree of filler structuring, but does not completely weaken the reinforcing contribution of the filler. Methyltrialkoxysilane reduces the localized hardening, stress concentration, and energy loss that may occur when the resilience enhancer is used alone, allowing the energy storage and recovery effect of the resilience enhancer to be more fully converted into macroscopic resilience performance. Simultaneously, the resilience enhancer further transforms the low internal friction interface brought about by methyltrialkoxysilane into a state of "softer and easier slippage," resulting in superior resilience and compression recovery. Therefore, this application does not simply achieve high resilience by increasing hardness or crosslinking density, but rather, while improving resilience and compression recovery, it helps maintain high elongation at break, good tear resistance, and moderate hardness, achieving a better balance between resilience and mechanical properties.

[0032] The third application employs a sequential process of "partial pretreatment of silica" and "addition of a resilience enhancer after heat treatment" to achieve the aforementioned synergistic effect stably and controllably. By pretreating only a portion of the silica with methyltrialkoxysilane, sufficient interfacial regulation can be established in the filler system, while retaining the reinforcing function of the untreated silica and avoiding a decrease in interfacial bonding due to excessive passivation of all filler surfaces. Simultaneously, the resilience enhancer is added after heat treatment of the base rubber compound, preventing it from prematurely participating in the filler interfacial interaction during the high-temperature mixing stage or being affected by the filler interface, thus avoiding uncontrolled dispersion and action. This allows it to be more primarily distributed within the silicone rubber network and form uniform high-recovery nodes during vulcanization. In other words, the process design of this application does not simply change the order of addition, but rather achieves complementarity between methyltrialkoxysilane and the resilience enhancer in terms of action stage and target through sequential control of "interfacial regulation first, network enhancement later," thereby ensuring the controllability and stability of the synergistic system. Attached Figure Description

[0033] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0034] Figure 1 Infrared spectrum of the resilience enhancer obtained in Example 1. Detailed Implementation

[0035] The various embodiments or implementation schemes in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments.

[0036] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0038] In this specification, unless otherwise specified, "parts" refers to "parts by weight".

[0039] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0040] Methyl vinyl silicone rubber: weight average molecular weight 500,000, vinyl content 0.10 wt%; Fumed silica: specific surface area is 200m² 2 / g; Methoxylated silicone oil: viscosity at 25℃ is 25 mPa·s, alkoxy content is 28 wt%; Hydroxyl silicone oil: viscosity 100 mPa·s at 25℃, hydroxyl content 0.85 wt%; Vinyl hydroxyl silicone oil: viscosity at 25℃ is 35 mPa·s, vinyl content is 6.5 mol%, hydroxyl content is 6 mol%; Methylhydrosiloxane: CAS: 1873-88-7.

[0041] Preparation Example 1: Preparation of resilience enhancer: 30 parts of triallyl isocyanurate were added to 450 parts of anhydrous toluene and stirred to dissolve under nitrogen protection. Then, 27 parts of methylhydrosiloxane were added, and the mixture was reacted at 70°C for 4 hours under the action of a platinum catalyst to obtain a crude material. After the reaction was completed, the mixture was cooled to room temperature, and the solvent and unreacted small molecules were removed by vacuum evaporation. After filtering to remove impurities, low-boiling substances were further removed under vacuum conditions of 50-80°C to obtain an isocyanurate derivative containing an isocyanurate ring, a heptamethyltrisiloxane propyl branch, and some allyl groups, which was used as a resilience enhancer.

[0042] Figure 1 The infrared spectrum of the obtained product, the resilience enhancer, is shown below. Figure 1 As shown, at 1750cm -1 A very strong and sharp downward absorption peak appears nearby, corresponding to the unsaturated stretching vibration of the imide carbonyl group (C=O) on the isocyanurate ring, confirming the intact existence of the isocyanurate core framework; at 1100 cm⁻¹ -1 Up to 1000cm -1 The region exhibits a broad and strong double downward absorption valley, which is a typical characteristic peak of the asymmetric stretching vibration of the siloxane covalent bond (Si-O-Si), proving the successful introduction of the heptamethyltrisiloxane; at 1260 cm⁻¹... -1A sharp and distinct characteristic absorption peak is observed nearby, corresponding to the symmetric deformation vibration of Si-CH3, echoing the Si-O-Si peak, confirming the organosilicon side-chain structure; at 2960 cm⁻¹... -1 There is a set of downward-pointing multiple spikes nearby, corresponding to the CH stretching vibration of saturated alkyl groups; at 1640 cm⁻¹ -1 An absorption peak can be observed nearby, and also at 910 cm⁻¹. -1 The presence of weak absorption peaks nearby corresponds to the stretching vibration of the unreacted terminal C=C double bond and the out-of-plane bending vibration of the =CH2 group, indicating that the product retains some allyl groups; the absorption peaks in the 2100~2250 cm⁻¹ range are also present. -1 The region has a flat baseline with no obvious Si-H absorption peaks, indicating that the active hydrogen in the raw material methylhydrosiloxane has been completely consumed by the hydrosilylation reaction.

[0043] Example 1 Preparation of high-resilience silicone rubber: Take 7 parts of fumed silica and add them to a high-speed mixer. Then add 0.5 parts of methyltrimethoxysilane and 0.3 parts of deionized water, mix for 12 minutes, then heat to 100℃ and keep warm for 30 minutes to obtain pretreated fumed silica. 100 parts of methyl vinyl silicone rubber, 5 parts of methoxy silicone oil, 1 part of hydroxy silicone oil, 0.45 parts of vinyl hydroxy silicone oil, and 0.12 parts of stearic acid were added to a kneader and premixed for 4 minutes. Then, pretreated fumed silica and the remaining 28 parts of fumed silica were added to the kneader and mixed for 45 minutes. The mixture was then heated to 165°C and kept at that temperature for 2 hours to obtain the base compound. Add 0.6 parts of the rebound enhancer and the base rubber compound to the rubber mixing mill. The rebound enhancer is the rebound enhancer prepared in Preparation Example 1. Mix for 5 minutes to make it evenly dispersed. Then add 1 part of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and continue mixing for 3 minutes. Then put the evenly mixed rubber compound into the mold and place it in the vulcanizing machine. Vulcanize at 170°C for 12 minutes to obtain the high-resilience silicone rubber product.

[0044] Comparative Example 1 Preparation of high-resilience silicone rubber: The experiment was largely the same as in Example 1, except that the resilience enhancer was replaced with 0.32 parts triallyl isocyanurate and 0.28 parts methylhydrosiloxane.

[0045] Comparative Example 2 Preparation of high-resilience silicone rubber: The experiment was largely the same as in Example 1, except that the resilience enhancer was replaced with 0.32 parts of triallyl isocyanurate.

[0046] Comparative Example 3 Preparation of high-resilience silicone rubber: The experiment was largely the same as in Example 1, except that the resilience enhancer was replaced with 0.28 parts of vinyldimethylsilane.

[0047] Comparative Example 4 Preparation of high-resilience silicone rubber: Take 7 parts of fumed silica and add them to a high-speed mixer. Then add 0.5 parts of methyltrimethoxysilane and 0.3 parts of deionized water, mix for 12 minutes, then heat to 100℃ and keep warm for 30 minutes to obtain pretreated fumed silica. 100 parts of methyl vinyl silicone rubber, 5 parts of methoxy silicone oil, 1 part of hydroxy silicone oil, 0.45 parts of vinyl hydroxy silicone oil, 0.12 parts of stearic acid, and 0.6 parts of resilience enhancer were added to a kneader and premixed for 4 minutes. The resilience enhancer was the one prepared in Preparation Example 1. Then, the pretreated fumed silica and the remaining 28 parts of fumed silica were added to the kneader and mixed for 45 minutes. The mixture was then heated to 165°C and kept at that temperature for 2 hours to obtain the base compound. Add the base rubber compound to the rubber mixing mill and mix for 5 minutes to disperse it evenly. Then add 1 part of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and continue mixing for 3 minutes. Then put the evenly mixed rubber compound into the mold and place it in the vulcanizing machine. Vulcanize at 170°C for 12 minutes to obtain the high-resilience silicone rubber product.

[0048] Comparative Example 5 Preparation of high-resilience silicone rubber: 100 parts of methyl vinyl silicone rubber, 5 parts of methoxy silicone oil, 1 part of hydroxy silicone oil, 0.45 parts of vinyl hydroxy silicone oil, and 0.12 parts of stearic acid were added to a kneader and premixed for 4 minutes. Then, 35 parts of fumed silica and 0.5 parts of methyltrimethoxysilane were added to the kneader and mixed for 45 minutes. The mixture was then heated to 165°C and kept at that temperature for 2 hours to obtain the base compound. Add 0.6 parts of the rebound enhancer and the base rubber compound to the rubber mixing mill. The rebound enhancer is the rebound enhancer prepared in Preparation Example 1. Mix for 5 minutes to make it evenly dispersed. Then add 1 part of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and continue mixing for 3 minutes. Then put the evenly mixed rubber compound into the mold and place it in the vulcanizing machine. Vulcanize at 170°C for 12 minutes to obtain the high-resilience silicone rubber product.

[0049] Comparative Example 6 Preparation of high-resilience silicone rubber: 100 parts of methyl vinyl silicone rubber, 5 parts of methoxy silicone oil, 1 part of hydroxy silicone oil, 0.45 parts of vinyl hydroxy silicone oil, and 0.12 parts of stearic acid were added to a kneader and premixed for 4 minutes. Then, 35 parts of fumed silica were added to the kneader and mixed for 45 minutes. The mixture was then heated to 165°C and kept at that temperature for 2 hours to obtain the base compound. Add 0.6 parts of the rebound enhancer and the base rubber compound to the rubber mixing mill. The rebound enhancer is the rebound enhancer prepared in Preparation Example 1. Mix for 5 minutes to make it evenly dispersed. Then add 1 part of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and continue mixing for 3 minutes. Then put the evenly mixed rubber compound into the mold and place it in the vulcanizing machine. Vulcanize at 170°C for 12 minutes to obtain the high-resilience silicone rubber product.

[0050] Comparative Example 7 Preparation of high-resilience silicone rubber: Take 7 parts of fumed silica and add them to a high-speed mixer. Then add 0.5 parts of methyltrimethoxysilane and 0.3 parts of deionized water, mix for 12 minutes, then heat to 100℃ and keep warm for 30 minutes to obtain pretreated fumed silica. 100 parts of methyl vinyl silicone rubber, 5 parts of methoxy silicone oil, 1 part of hydroxy silicone oil, 0.45 parts of vinyl hydroxy silicone oil, and 0.12 parts of stearic acid were added to a kneader and premixed for 4 minutes. Then, pretreated fumed silica and the remaining 28 parts of fumed silica were added to the kneader and mixed for 45 minutes. The mixture was then heated to 165°C and kept at that temperature for 2 hours to obtain the base compound. Add the base rubber compound to the rubber mixing mill and mix for 5 minutes to disperse it evenly. Then add 1 part of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and continue mixing for 3 minutes. Then put the evenly mixed rubber compound into the mold and place it in the vulcanizing machine. Vulcanize at 170°C for 12 minutes to obtain the high-resilience silicone rubber product.

[0051] Comparative Example 8 Preparation of high-resilience silicone rubber: 100 parts of methyl vinyl silicone rubber, 5 parts of methoxy silicone oil, 1 part of hydroxy silicone oil, 0.45 parts of vinyl hydroxy silicone oil, and 0.12 parts of stearic acid were added to a kneader and premixed for 4 minutes. Then, 35 parts of fumed silica were added to the kneader and mixed for 45 minutes. The mixture was then heated to 165°C and kept at that temperature for 2 hours to obtain the base compound. Add the base rubber compound to the rubber mixing mill and mix for 5 minutes to disperse it evenly. Then add 1 part of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and continue mixing for 3 minutes. Then put the evenly mixed rubber compound into the mold and place it in the vulcanizing machine. Vulcanize at 170°C for 12 minutes to obtain the high-resilience silicone rubber product.

[0052] Test section Resilience: According to the national standard GB / T1681-2009 Determination of resilience of vulcanized rubber, high-resilience silicone rubber products of each example and comparative example were made into samples. The resilience of the samples was tested under the conditions of room temperature 25℃ and humidity 50%. The test results are shown in Table 1.

[0053] Compression set: According to the national standard GB / T7759.1-2015 Determination of compression set of vulcanized rubber or thermoplastic rubber, high-resilience silicone rubber products of each example and comparative example were made into samples. The samples were subjected to compression set test under the conditions of room temperature 25℃ and humidity 50%. The test results are shown in Table 1.

[0054] Hardness: According to the national standard GB / T39693.4-2025 Determination of hardness of vulcanized rubber or thermoplastic rubber - Part 4: Determination of indentation hardness by Shore hardness tester (Shore hardness), high-resilience silicone rubber products of each example and comparative example were made into samples. The hardness of the samples was tested under the conditions of room temperature 25℃ and humidity 50%. The test results are shown in Table 1.

[0055] Elongation at break: According to the national standard GB / T528-2009 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber, high-resilience silicone rubber products of each example and comparative example were made into samples. The elongation at break of the samples was tested under the conditions of room temperature 25℃ and humidity 50%. The test results are shown in Table 2.

[0056] Tear strength: According to the national standard GB / T528-2008 Determination of tear strength of vulcanized rubber or thermoplastic rubber, high-resilience silicone rubber products of each example and comparative example were made into samples. The tear strength of the samples was tested under the conditions of room temperature 25℃ and humidity 50%. The test results are shown in Table 2.

[0057] Table 1

[0058] Table 2

[0059] As demonstrated by Examples 1 and 1 Comparatively, the technical effect of the rebound enhancer of the present invention stems from its pre-constructed specific molecular structure, rather than a simple superposition of raw material components. Although Comparatively, triallyl isocyanurate and vinyl dimethylsilane, corresponding to those in Example 1, were added, they were not pre-reacted, making it difficult to form the same structural units as in Example 1 during silicone rubber compounding and vulcanization. Therefore, the same network regulation effect as in Example 1 could not be achieved. In contrast, Example 1, by pre-preparing the rebound enhancer and introducing it into the system in a stable and uniform structural form, resulted in silicone rubber exhibiting superior overall performance in terms of resilience, compression set, elongation at break, and tear strength. This result fully demonstrates that the structural design of the rebound enhancer of the present invention plays a crucial role in improving the overall performance of high-resilience silicone rubber.

[0060] A comparison of Example 1 and Comparative Example 2 shows that, with other raw material compositions, interface adjustment methods, mixing processes, and vulcanization conditions remaining basically the same, the overall performance of the silicone rubber significantly decreased after replacing the rebound reinforcing agent described in this invention with triallyl isocyanurate alone. The results indicate that while triallyl isocyanurate can participate in vulcanization network formation to some extent, it is difficult to achieve the same overall adjustment effect as the rebound reinforcing agent of this invention. Because the rebound reinforcing agent of this invention is pre-structured, it can better balance the material's flexibility and tear resistance while improving network recovery ability; therefore, its function cannot be replaced by triallyl isocyanurate alone.

[0061] A comparison of Example 1 and Comparative Example 3 shows that, under essentially the same conditions, simply replacing the resilience enhancer described in this invention with vinyldimethylsilane does not yield performance similar to that of Example 1. Although Comparative Example 3 achieved an elongation at break of 752%, indicating that its system maintained a certain degree of flexibility, its resilience and compression recovery were significantly insufficient. This suggests that vinyldimethylsilane itself cannot form an effective high-recovery network structure, nor can it impart excellent tear resistance to the material. Therefore, the resilience enhancer described in this invention does not originate from a single small molecule component, but rather from a pre-constructed specific molecular structure that can simultaneously improve the resilience, compression recovery, and overall mechanical properties of silicone rubber.

[0062] A comparison between Example 1 and Comparative Example 4 shows that, under the conditions of using the same resilience enhancer and the same methyltrialkoxysilane, the timing of the addition of the resilience enhancer has a significant impact on the final performance. In Comparative Example 4, the resilience enhancer was added to the kneader and mixed with the basic formulation in advance, while in Example 1, the resilience enhancer was added to the mixing mill after the basic rubber compound was formed. The test results show that if the resilience enhancer is added to the system in advance during the mixing of silica and high-temperature heat treatment, it is easy to weaken its directional regulation effect on the subsequent vulcanization network, and may lead to excessive local effects in the system, resulting in increased hardness, decreased elongation, and deterioration of overall performance. However, the method of "adding the resilience enhancer after the basic rubber compound is formed" as described in Example 1 is more conducive to its network reinforcement and resilience regulation effects during the vulcanization stage.

[0063] A comparison between Example 1 and Comparative Example 5 shows that the pretreatment method of methyltrimethoxysilane for silica also has a significant impact on the properties of high-resilience silicone rubber. Although methyltrimethoxysilane was added to Comparative Example 5, the silica was not pretreated; instead, it was directly added to the kneader along with all the silica for mixing. In Example 1, a portion of the silica was treated with methyltrimethoxysilane before being added to the system along with the remaining silica. The test results indicate that methyltrimethoxysilane does not simply exist in the system to exert its optimal effect. Only by pre-treating the silica interface can the structural interactions and interfacial energy dissipation between silica particles be effectively reduced, thereby better cooperating with the resilience enhancer and ultimately achieving superior resilience and overall mechanical properties.

[0064] A comparison of Example 1 and Comparative Example 6 shows that, under the same conditions of adding the same resilience enhancer and in the same manner, the introduction of methyltrimethoxysilane has a significant impact on the overall performance of silica-filled silicone rubber. Comparative Example 6 did not add methyltrimethoxysilane, relying solely on the resilience enhancer to adjust the system; Example 1, however, introduced methyltrimethoxysilane to pretreat the silica interface. Test results indicate that while relying solely on the resilience enhancer can improve the resilience and compression recovery of silicone rubber to some extent, it also easily leads to material hardening and a decrease in elongation. The introduction of methyltrimethoxysilane optimizes the silica interface, mitigating the side effects of filler structuring, thereby better balancing resilience with flexibility and tear resistance.

[0065] A comparison of Example 1 and Comparative Example 7 shows that while methyltrialkoxysilane alone can improve the flexibility and interfacial state of silica-filled silicone rubber to some extent, it is difficult to achieve the same high resilience as the present invention. Comparative Example 7 added methyltrimethoxysilane and pretreated the silica, but did not add a resilience enhancer; Example 1, on the other hand, further added a resilience enhancer. Test results show that adding methyltrialkoxysilane alone helps maintain the material's softness and ductility, but its resilience and compression recovery are significantly insufficient, making it difficult to meet the requirements of high resilience products. This indicates that methyltrialkoxysilane mainly addresses the filler interface problem, while achieving high resilience still requires effective control of the vulcanization network by a resilience enhancer.

[0066] A comparison of Example 1 and Comparative Example 8 shows that, without the addition of a resilience enhancer and methyltrialkoxysilane, the overall performance of the basic silicone rubber system is significantly lower than that of the present invention. The test results indicate that the present invention, by simultaneously introducing a resilience enhancer and methyltrialkoxysilane, significantly improves the resilience and tear resistance of the material while maintaining a high elongation of the silicone rubber, and substantially reduces compression set. In particular, Example 1 shows a significant improvement in both resilience and compression recovery even with only a slight increase in hardness, indicating that the present invention does not simply achieve high resilience by increasing material hardness, but rather achieves performance optimization through the synergistic regulation of the silica interface and the vulcanization network.

[0067] Finally, it should be noted that 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 method for preparing high-resilience silicone rubber, characterized in that, Includes the following steps: S1. Provides 100 parts of methyl vinyl silicone rubber, 30-40 parts of fumed silica, 3-7 parts of methoxy silicone oil, 0.5-1.5 parts of hydroxy silicone oil, 0.3-0.6 parts of vinyl hydroxy silicone oil, 0.1-0.2 parts of stearic acid, 0.5-1.5 parts of vulcanizing agent, 0.2-1.0 parts of resilience enhancer, and 0.1-1.0 parts of methyltrialkoxysilane; wherein the resilience enhancer is obtained by hydrosilylation reaction of triallyl isocyanurate and methylhydrosiloxane; S2. The methyltrialkoxysilane is mixed with a portion of fumed silica for pretreatment to obtain pretreated fumed silica; S3. The pretreated fumed silica is mixed with the remaining fumed silica, methyl vinyl silicone rubber, methoxy silicone oil, hydroxy silicone oil, stearic acid and vinyl hydroxy silicone oil and then heat-treated to obtain the base compound; S4. Add a resilience enhancer and a vulcanizing agent to the base rubber compound and mix them together. After vulcanization molding, a high resilience silicone rubber product is obtained.

2. The method for preparing high-resilience silicone rubber according to claim 1, characterized in that, The methyltrialkoxysilane includes at least one of methyltrimethoxysilane and methyltriethoxysilane.

3. The method for preparing high-resilience silicone rubber according to claim 1, characterized in that, The preparation method of the resilience enhancer includes the following steps: 30 parts of triallyl isocyanurate were added to 300-600 parts of anhydrous toluene and stirred to dissolve under nitrogen protection. Then, 25-30 parts of methylhydrosiloxane were added, and the mixture was reacted at 60-75°C under the action of a platinum catalyst. The Si-H bonds of the methylhydrosiloxane underwent a platinum-catalyzed hydrosilylation addition reaction with some of the allyl double bonds in the triallyl isocyanurate to obtain an isocyanurate derivative containing an isocyanurate ring, a heptamethyltrisiloxane propyl branch, and some allyl groups, which can be used as a resilience enhancer.

4. The method for preparing high-resilience silicone rubber according to claim 3, characterized in that, The reaction time is 3-5 hours.

5. The method for preparing a high-resilience silicone rubber according to claim 1, characterized in that, The vulcanizing agent is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane.

6. The method for preparing a high-resilience silicone rubber according to claim 1, characterized in that, The specific surface area of ​​the fumed silica is 150~250m². 2 / g.

7. The method for preparing high-resilience silicone rubber according to claim 1, characterized in that, The weight-average molecular weight of the methyl vinyl silicone rubber is 4.5 × 10⁻⁶. 5 ~6.5×10 5 The vinyl content is 0.05~0.15wt%.

8. The method for preparing high-resilience silicone rubber according to claim 1, characterized in that, Includes the following steps: S1. Provides 100 parts of methyl vinyl silicone rubber, 30-40 parts of fumed silica, 3-7 parts of methoxy silicone oil, 0.5-1.5 parts of hydroxy silicone oil, 0.3-0.6 parts of vinyl hydroxy silicone oil, 0.1-0.2 parts of stearic acid, 0.5-1.5 parts of vulcanizing agent, 0.2-1.0 parts of resilience enhancer, and 0.1-1.0 parts of methyltrialkoxysilane; wherein the resilience enhancer is obtained by hydrosilylation reaction of triallyl isocyanurate and methylhydrosiloxane; S2. Take 10~25wt% of fumed silica and add it to a high-speed mixer. Then add methyltrialkoxysilane and water, mix for 10~15min, then heat to 80~110℃ and keep warm for 20~45min to obtain pretreated silica. S3. Add methyl vinyl silicone rubber, methoxy silicone oil, hydroxy silicone oil, stearic acid and vinyl hydroxy silicone oil to a kneader and premix for 3-5 minutes. Then add the pretreated fumed silica and the remaining fumed silica to the kneader and mix for 30-60 minutes. Heat to 160-170°C and keep warm for 1.5-2.5 hours to obtain the base compound. S4. Add the rebound enhancer and the base rubber compound to the rubber mixing mill and mix for 3-8 minutes to disperse them evenly. Then add the vulcanizing agent and continue mixing for 2-5 minutes. Place the evenly mixed rubber compound in the vulcanizing mill and vulcanize at 165-175°C for 10-15 minutes to obtain the high-resilience silicone rubber product.

9. A high-resilience silicone rubber product, characterized in that, The preparation method according to any one of claims 1 to 8 is obtained.

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