Temperature-sensitive silicone rubber-based composite material and method for producing the same

Abstract

The present invention relates to a temperature-sensitive composite material comprising a silicone rubber matrix and a bio-based aliphatic unsaturated polyester phase, aimed at addressing the technical conflict between anatomical adaptability and structural stability in wearable devices. The present invention enables a dramatic mechanical transition triggered by human heat through precise design of molecular structure, particularly by adjusting the odd-even carbon ratio in the alkyl chain to disrupt crystalline packing. This molecular engineering ensures a significant reduction in hardness within the physiological temperature window, enabling the material to conform to unique anatomical contours when in contact with the skin. Furthermore, the introduction of unsaturated units promotes the formation of a post-crosslinked network, thereby building a biphasic synergistic structure that enables the material to maintain the necessary structural integrity and tactile texture even in a softened state. The present system provides a sustainable solution for injection-molded wearable devices, ensuring consistent compliance and mechanical durability under cyclic temperature changes.

Description

Cross-reference to related applications

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 790,762, filed April 18, 2025, and U.S. Patent Application No. 19 / 562,857, filed March 11, 2026, which are incorporated herein by reference in their entirety. Technical Field

[0002] This invention relates to the field of silicone rubber-based composite materials. Background Technology

[0003] Wearable devices such as earbuds, smartwatch straps, and medical wearables are increasingly adopting silicone materials due to their durability, non-allergenicity, and flexibility. In the manufacturing of wearable / skin-contact devices, especially injection-molded components, silicone elastomers dominate the market due to their combination of softness and structural integrity. However, traditional silicone technology faces a key challenge: achieving optimal comfort while maintaining a secure fit. Traditional silicone materials often fail to adapt to the unique contours of the user's body, resulting in excessive contact pressure, poor fit, and degraded device performance. For example, in earbud applications, the unique shape of the ear canal requires materials that precisely conform to individual contours without causing discomfort during prolonged wear. While traditional silicone earbud tips are biocompatible, they typically exhibit static rigidity and cannot adapt to changes in body temperature or pressure. This rigidity can lead to user fatigue, improper fit, or slippage, impairing comfort and audio performance. Similarly, watch straps made of standard silicone rubber may create localized pressure points or fail to maintain their shape over time, reducing wearability and comfort.

[0004] Current solutions to this problem include using thermoplastic elastomers (TPEs) or modified silicone components to enhance the softness of silicone rubber (e.g., Chinese patent application publication number CN107018664A). However, softer materials often come at the cost of mechanical stability, leading to shorter product lifespan or unstable wear. Furthermore, such materials lack temperature-adaptive properties, limiting biocompatibility at body temperature. Multi-material designs (e.g., layered structures combining rigid and flexible regions) have also been explored. However, these methods complicate manufacturing processes, increase costs, and often lack precision.

[0005] Furthermore, many traditional polymers rely on non-renewable resources, which contradicts industry's growing demand for sustainable manufacturing. For example, PCT international patent applications WO2024147395A1 and WO2023068853A1 utilize materials such as caprolactone and glycidyl methacrylate to introduce temperature-sensitive shape memory functionality into silicone rubber, both of which are typically derived from petrochemical resources. While these methods enable silicone rubber to adapt to temperature changes, they are limited by the inherent properties of the materials used. Specifically, polycaprolactone has an equilibrium melting point of 55°C, which limits the ability to fine-tune the melt and transition temperatures within a target range of 20°C to 40°C, a range crucial for wearable products that need to respond effectively to body temperature (typically between 28°C and 38°C).

[0006] Therefore, there is a need for a silicon-based material with improved temperature adaptability and mechanical stability to overcome the limitations of traditional silicon technology. This material should provide comfort, a secure fit, and durability for wearable devices, while remaining soft, flexible, and sustainably sourced. Summary of the Invention

[0007] This invention provides a novel composite material of silicone rubber and bio-based aliphatic unsaturated polyester, aiming to address the critical challenge of balancing dynamic comfort and structural stability in wearable devices. Specifically, the main objective of this invention is to overcome the long-standing technical conflict between anatomical adaptability and structural stability.

[0008] According to a first aspect, the present invention provides a temperature-sensitive silicone rubber-based composite material. The temperature-sensitive silicone rubber-based composite material comprises 20 to 90 parts by weight of a silicone rubber matrix; 10 to 80 parts by weight of a temperature-sensitive elastic polymer dispersed in the silicone rubber matrix; and 0.1 to 30 parts by weight of an additive, the additive comprising a crosslinking initiator. The temperature-sensitive elastic polymer comprises an aliphatic unsaturated polyester having a backbone configured to undergo a crystallization-amorphous phase transition within a physiological temperature window of 20°C to 40°C. The silicone rubber matrix and the post-crosslinked network of the aliphatic unsaturated polyester form a biphase synergistic structure, such that the temperature-sensitive silicone rubber-based composite material exhibits a decrease in Shore A hardness of at least 20 units upon reaching the phase transition, while maintaining structural elasticity.

[0009] According to one embodiment, the aliphatic unsaturated polyester comprises a polyester structure represented by formula (I): Formula (I), Among them, R x and R yEach group is independently selected from the following groups: C 1-15 straight-chain alkyl, C 1-15 Branched alkyl groups, and C groups containing at least one carbon-carbon double bond 2-15 Alkenyl group, where m is an integer greater than or equal to 1.

[0010] According to one embodiment, the R x It includes at least two alkyl components, one with an odd number of carbon atoms and the other with an even number of carbon atoms, configured to regulate the crystalline stacking of the polyester. The R... y It includes unsaturated aliphatic groups, which are configured to form a post-crosslinking network with the silicone rubber matrix.

[0011] According to one embodiment, the temperature-sensitive elastic polymer exhibits a melting enthalpy of at least 50 J / g, ensuring nonlinear mechanical transformation within the physiological temperature range.

[0012] According to one embodiment, the temperature-sensitive elastic polymer has a melting temperature between 30°C and 40°C. The crystallization temperature of the temperature-sensitive elastic polymer is between 10°C and 21°C.

[0013] According to one embodiment, the ratio of the elastic modulus of the temperature-sensitive silicone rubber-based composite material at 10°C to its elastic modulus at 40°C is at least 5.8.

[0014] According to one embodiment, the temperature-sensitive silicone rubber-based composite material exhibits a Shore A hardness variation of 0.1 to 70 units in the temperature range of 10°C to 45°C.

[0015] According to one embodiment, the weight-average molecular weight of the temperature-sensitive elastic polymer is in the range of 10 kDa to 100 kDa.

[0016] According to one embodiment, the silicone rubber matrix comprises a thermosetting silicone resin selected from the group consisting of polydimethylsiloxane (PDMS) and vinyl-functionalized silicone elastomers.

[0017] According to one embodiment, the additive includes peroxides, platinum-based catalysts, azo compounds, photoinitiators or thermal initiators, reinforcing fillers or silicon additives.

[0018] According to one embodiment, the post-crosslinking network is formed during the molding process by triggering free radical polymerization of unsaturated units within the polyester using the crosslinking initiator.

[0019] According to one embodiment, after undergoing at least 30 repeated heating-cooling cycles between 10°C and 70°C, the temperature-sensitive silicone rubber-based composite material retains its Shore A hardness at 45°C.

[0020] According to one embodiment, the temperature-sensitive silicone rubber-based composite material has an elastic modulus of not less than 2.7 MPa at 40°C, preventing the structure from collapsing in a softened state.

[0021] According to one embodiment, the temperature-sensitive silicone rubber-based composite material is configured as an injection-molded component for a wearable device, the temperature-sensitive silicone rubber-based composite material anatomically fitting the user's skin surface when in contact with the user's skin.

[0022] According to another aspect, the present invention provides a method for preparing a temperature-sensitive silicone rubber-based composite material, comprising (a) mixing silicone rubber with additives to form a first mixture; (b) incorporating a temperature-sensitive elastic polymer into the first mixture to form a second mixture; (c) homogenizing the second mixture by a kneading process under an inert gas atmosphere; and (d) molding the homogenized mixture into a predetermined shape at a temperature between 100°C and 190°C to simultaneously trigger molding and crosslinking of the temperature-sensitive elastic polymer.

[0023] According to one embodiment, the method further includes a post-curing step at a temperature between 100°C and 150°C for 4 to 20 hours.

[0024] According to one embodiment, the molding process is carried out under vacuum conditions to minimize air inclusions and defects within the dual-phase synergistic structure.

[0025] According to one embodiment, the temperature-sensitive elastic polymer is pre-synthesized from bio-based diols and dicarboxylic acids, and the melting temperature is customized to 20°C to 40°C by adjusting the odd-even carbon ratio in its molecular backbone.

[0026] The key technological breakthrough of this invention lies in the precise customization of the molecular structure of the thermoresponsive polymer phase, engineered to achieve a sensitive and controllable mechanical transformation within the critical physiological window of 20°C-40°C. Unlike existing materials (such as polycaprolactone) whose melting points far exceed the skin's tolerance limits (typically above 55°C), this invention utilizes the precise customization of the molecular structure of the polymer backbone (R... x and R y Strategic control of the alkyl chain length and the odd-even carbon ratio within the composite material enables high-precision destruction of crystal stacking. This molecular engineering design results in a non-linear, dramatic decrease in Shore A hardness (up to 70 units) and a decrease in elastic modulus (E'). 10°C / E'40°C The value is at least 5, which allows the material to accurately fit the unique anatomical contours when in contact with body temperature.

[0027] Furthermore, this invention addresses a significant technical bias in materials science: the inherent loss of mechanical integrity in polymers during thermal softening. By introducing unsaturated aliphatic units capable of post-crosslinking, this invention constructs a biphase synergistic structure. While the dispersed polymer phase undergoes a phase transition to provide adaptive softness, the silicone rubber matrix and crosslinked network maintain fundamental structural elasticity and durability, preventing the device from losing its functional shape or tactile feel. This soft yet resilient synergistic mechanism provides a degree of dynamic comfort and structural retention that cannot be achieved solely through the physical blending of ordinary elastomers.

[0028] Furthermore, this invention prioritizes environmental sustainability without sacrificing technical performance, giving it a significant advantage over existing technologies. By utilizing bio-based monomers derived from natural diols and dicarboxylic acids, the formulation maintains controlled crystallinity, thereby enhancing temperature responsiveness. This dual focus on high-performance mechanical adaptability and environmentally friendly material design represents a significant advancement over existing petroleum-based technologies, making it an ideal solution for advanced consumer electronics and medical wearable applications. Attached Figure Description

[0029] Embodiments of the invention are described in more detail below with reference to the accompanying drawings, in which:

[0030] Figure 1 The transition temperature (characterized by polyester UAP01 in Example 2) is shown by differential scanning calorimetry (DSC) test results.

[0031] Figure 2 Describe the results of the Dynamic Mechanics Analysis (DMA) test.

[0032] Figure 3 The results of the Shore A hardness test are displayed.

[0033] Figure 4 A graph depicting the cyclic heating and cooling temperature profiles applied to the temperature-sensitive silicon composite material (UAP03) during the durability test sequence.

[0034] Figure 5 The DMA results of the comparative silicon composite material (SC09) prepared in Comparative Example 2 are depicted. Detailed Implementation

[0035] definition

[0036] Throughout this specification, unless the context otherwise requires, the word “comprise” or variations such as “comprises” or “comprising” should be understood to imply inclusion of the stated whole or group of wholes, but not to exclude any other whole or group of wholes. It should also be noted that in this disclosure and particularly in the claims and / or paragraphs, terms such as “comprises,” “comprised,” and “comprising” may have the meaning attributed to them under U.S. patent law, for example, allowing for elements not expressly listed but excluding elements present in the prior art or affecting the essential or novel characteristics of the invention.

[0037] Furthermore, throughout this specification and claims, unless the context otherwise requires, the word "include" or variations thereof, such as "includes" or "including," shall be understood to imply inclusion of the stated whole or group of wholes, but not to exclude any other whole or group of wholes.

[0038] As used herein and unless otherwise defined, the terms “substantially,” “basically,” “approximately,” and “about” are used to describe and explain small variations. When used in conjunction with an event or situation, the terms may cover instances where the event or situation occurred precisely or instances where the event or situation was close to occurring. For example, when used in conjunction with a numerical value, the terms may cover a range of variation less than or equal to ±10% of the numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%.

[0039] References to "an embodiment," "an example embodiment," "exemplary embodiment," etc., in this specification indicate that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, it is assumed that the effect of such feature, structure, or characteristic in conjunction with other embodiments is within the knowledge of those skilled in the art, whether explicitly described or not.

[0040] In the preparation methods described herein, steps may be performed in any order without departing from the principles of the invention, except where the time or order of operations is explicitly stated. A statement in a claim that implies performing a step first, followed by several other steps, should be interpreted as meaning that the first step is performed before any other steps, but the other steps may be performed in any suitable order unless the order is further stated in the other steps. For example, a claim element stating "steps A, B, C, D, and E" should be interpreted as meaning that step A is performed first, and step E is performed last, and steps B, C, and D may be performed in any order between steps A and E, and such order still falls within the literal scope of the claimed process. A given step or subset of steps may also be repeated. Furthermore, unless the explicit claim language states that the specified steps are performed separately, the specified steps may be performed simultaneously.

[0041] As used herein, the term "temperature-sensitive elastic polymer" refers to a polymer material that exhibits a reversible change in at least one mechanical property in response to temperature changes within a predetermined temperature range.

[0042] As used herein, the term "transition temperature" refers to the temperature at which a polymer undergoes a thermal or mechanical phase transition that can be detected by differential scanning calorimetry, dynamic thermomechanical analysis, or hardness measurement.

[0043] As used in this article, the term "physiological temperature range" refers to the temperature range that corresponds to the temperature encountered during contact with the human body.

[0044] As used in this article, the term "elastic modulus ratio" refers to the ratio of the storage modulus values ​​measured at two different temperatures under the same dynamic thermomechanical analysis conditions.

[0045] As used herein, the term “odd-even carbon number regulation” refers to the controlled selection and incorporation of polymer building units with alkyl chains having odd and even carbon atoms within the polymer structure.

[0046] As used herein, the term "post-crosslinking" refers to the crosslinking reaction that occurs after the formation of the polymer backbone by activating reactive groups within the polymer.

[0047] As used herein, the term "biphase synergistic structure" refers to a composite structure that includes a silicone rubber phase and a temperature-sensitive elastic polymer phase coexisting within the material.

[0048] As used herein, the term "temperature-sensitive silicone rubber-based composite material" refers to a composite material comprising a silicone rubber matrix and a temperature-sensitive elastic polymer dispersed therein.

[0049] Other definitions of the selected terms used herein can be found in the specific description of the invention and apply throughout. Unless otherwise defined, all other technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0050] In the following description, the temperature-sensitive silicone rubber polyester composite material, its preparation method, and its uses are described as preferred embodiments. It will be apparent to those skilled in the art that modifications, including additions and / or substitutions, can be made without departing from the scope and spirit of the invention. To avoid obscuring the core of the invention, some specific details may be omitted; however, this specification is intended to enable those skilled in the art to practice the disclosed technical solutions without excessive experimentation.

[0051] While traditional silicone elastomers are durable, their inherent static rigidity makes them difficult to conform to the unique and complex contours of the human body (such as the ear canal or wrist), leading to localized pressure concentration, discomfort, and reduced device performance. By precisely designing the molecular structure of a bio-based unsaturated polymer phase, this invention provides a material system capable of triggering a dramatic and predictable mechanical response by body heat. This allows the composite material to precisely soften and conform to the user's skin within a critical physiological temperature window, while maintaining necessary structural integrity, elasticity, and tactile texture through its elastic silicone matrix.

[0052] In particular, the present invention provides a temperature-sensitive silicone rubber-based composite material, its preparation method, and its applications. This temperature-sensitive composite material is specifically designed for injection-molded wearable applications, such as earbud heads, smartwatch straps, and medical wearable devices, where precise fit, comfort, and durability are crucial.

[0053] The temperature-sensitive silicone rubber-based composite material comprises the following components: 20 to 90 parts by weight of silicone rubber, 10 to 80 parts by weight of temperature-sensitive elastic polymer, and 0.1 to 30 parts by weight of additives.

[0054] The silicone rubber used as a base material is selected from A / B two-component or one-component silicone rubber formulations, providing essential skin-friendly properties, including softness, biocompatibility, and flexibility. The hardness of silicone rubber can be customized according to specific applications, ranging from 0.1A to 100A on the Shore A hardness scale.

[0055] In one embodiment, the silicone rubber may include thermosetting silicone rubber materials and composite silicone rubber materials including grafted polymers.

[0056] In one embodiment, the temperature-sensitive elastic polymer comprises a structure represented by formula (I):

[0057] Formula (I): , Among them, R x and R y Represented independently by one or more aliphatic hydrocarbons, wherein R x R can be represented x1 R x2 R x3 ...and R y R can be represented y1 R y2 R y3 ...etc. R x and R y Choose independently the group consisting of the following items: C 1-15 straight-chain alkyl, C 1-15 Branched alkyl groups, C containing one or two carbon-carbon double bonds 2-15 Straight-chain alkenyl and C 2-15 Branched alkenyl group. m is an integer greater than or equal to 1.

[0058] In one embodiment, R x and R y The reactant monomers are derived from natural biological sources. x Preferred selection from C 3-6 A straight-chain alkyl group, comprising at least two alkyl components, one having an odd number of carbon atoms and the other having an even number of carbon atoms. R y Preferably, it is selected from straight-chain alkyl groups with an even number of carbon atoms, and the number of carbon atoms is preferably not less than 8. y It is also preferably selected from unsaturated alkyl groups containing at least one carbon-carbon double bond.

[0059] In another embodiment, R y Preferably according to the aforementioned R x The adjustment method can be selected. And R x Preferably according to the aforementioned R y The adjustment method can be selected, provided that R... x With R y Do not select the same adjustment method.

[0060] In one embodiment, the temperature-sensitive elastic polymer comprises a polyester. The polyester includes chain-like alkyl units that affect the transition temperature, which can be adjusted based on the length of the alkyl chains. The polyester also contains unsaturated alkyl units that promote crosslinking, thereby improving mechanical strength.

[0061] Polyesters belong to a family of polymers characterized by ester functional groups (–O–CO–) in their main chain and are typically synthesized via polycondensation reactions of diols with dicarboxylic acids (e.g., terephthalic acid, adipic acid, sebacic acid, isophthalic acid, itaconic acid, etc.). The diols and dicarboxylic acids used to synthesize polyesters or polyols can be selected from monomers derived from natural biological resources. The manufacturing process is eco-friendly and environmentally sustainable. The transformation temperature of the polyester main chain is precisely controlled by the number of alkyl units and the number of carbon atoms within these units. Using dicarboxylic acids or diols with even and odd carbon chains as raw materials can result in different crystallization abilities. For example, polyesters synthesized from dicarboxylic acids and diols with an even number of carbon atoms typically have higher crystallization temperatures and crystallinity. The larger the number of carbon atoms, the higher the crystallization temperature and crystallinity. Conversely, polyesters synthesized from dicarboxylic acids and diols with an odd number of carbon atoms are typically amorphous. By selecting R as shown in formula (I), x or R y Different numbers and proportions of odd and even carbon atoms in the components can be used to synthesize polyesters with controllable crystallization temperature and crystallinity.

[0062] In one embodiment, the transition temperature and the sharpness of the mechanical phase transition are nonlinearly controlled by multivariate synergistic optimization of the following factors: (i) the precise number of carbon atoms in the straight-chain alkyl component within the monomer; (ii) the critical molar ratio between different diol monomers; (iii) the stoichiometric ratio between different dicarboxylic acid monomers; and (iv) the controlled degree of polymerization.

[0063] A key finding of this invention is that the transformation behavior within the critical temperature range cannot be achieved simply by selecting arbitrary monomers. Instead, it requires a specific odd-even carbon effect disruption, where the interactions between odd and even carbon chains are strategically balanced to suppress over-crystallization while maintaining sufficient latent heat for rapid hardness reduction. This precise mechanical response achieves an elastic modulus ratio (E') of at least 5 within a narrow range of 20°C. 10°C / E' 40°C This represents an unexpected technical effect that surpasses the predictable results of conventional experiments in traditional polymer blending.

[0064] In one embodiment, the temperature-sensitive elastic polymer enables the material to undergo a hardness transition in a temperature range of 10°C to 45°C, preferably in the range of 20°C to 40°C.

[0065] The hardness of the temperature-sensitive silicone rubber depends on the ratio between the elastic silicone rubber and the elastic polyester. The hardness can be adjusted within a range of 0.1 to 70 Shore A.

[0066] Materials with low melting points often suffer from insufficient mechanical properties, limiting their practical applications. To address this challenge, introducing double bonds for post-crosslinking in diacids such as maleic acid, methyl fumaric acid, and itaconic acid offers a solution. During their polymerization, these diacids integrate their reactive C=C double bonds into the polyester backbone. During post-processing, these double bonds can be activated via free radical polymerization or UV / electron beam / gamma-ray curing to form a crosslinked network. This network enhances mechanical strength by restricting the mobility of molecular chains, thereby increasing tensile strength and modulus without significantly altering the material's low melting point. By carefully controlling the degree of crosslinking and the number of double bonds, a balance can be achieved between mechanical strengthening and the various thermal properties required to maintain functionality.

[0067] To determine the transition temperature, the composite material was subjected to a heating-cooling-heating scan from -50°C to 150°C using DSC. (Refer to...) Figure 1 The endothermic peak observed during the second heating cycle was identified as a marker of the phase transition temperature. The figure illustrates the second heating cycle and highlights the endothermic peak indicating the material's phase transition temperature. The observed peak confirms that the composite material exhibits a sharp transition temperature, which can be adjusted from 20°C to 40°C by varying the polyester composition. The enthalpy change (ΔH) associated with this transition reflects the material's crystallinity, ensuring its responsiveness to temperature changes. This property is crucial for applications requiring body temperature adaptability, such as wearable devices.

[0068] Another way to characterize the composite material is through DMA (Viscoelasticity Measurement). It measures the viscoelasticity of the material by applying oscillating stress and monitoring the strain response at a controlled temperature or frequency. (See reference...) Figure 2 This figure shows the storage modulus (elastic modulus) and loss modulus as a function of temperature. A significant decrease in storage modulus is observed between 10°C and 40°C, indicating a substantial reduction in stiffness with increasing temperature. The ratio of the elastic modulus at 10°C to that at 40°C is not less than 5, demonstrating the material's ability to dynamically soften at body temperature. This property ensures improved fit and comfort in skin-contact applications while maintaining structural stability at lower temperatures.

[0069] In addition, the composite material was subjected to Shore A hardness testing (ASTM D2240). Figure 3 The Shore A hardness test results of this temperature-sensitive silicone rubber composite material are presented. The data show that the hardness decreases significantly with increasing temperature, with a hardness difference exceeding 20 Shore A units between 10°C and 40°C. This transformation confirms the temperature-dependent mechanical properties of the composite material, allowing it to achieve a balance between softness and strength. These properties make this material particularly suitable for wearable devices that require both durability and adaptability to human body contours.

[0070] To ensure good mechanical properties and structural integrity, the molecular weight of the polyester component is a key factor. The number-average molecular weight of this polymer is in the range of 10 kDa to 100 kDa, and preferably between 20 kDa and 50 kDa.

[0071] The polyester typically exhibits a number-average molecular weight greater than 10 kDa, preferably greater than 20 kDa. This specific molecular weight range ensures an optimal balance between mechanical strength and elasticity. In this invention, the molecular weight of the polyester is measured using gel permeation chromatography (GPC).

[0072] Additives play a crucial and cyclical role in material properties, including initiators such as peroxides (e.g., dicumyl peroxide, benzoyl peroxide, ketal peroxides, and other peroxide derivatives) or platinum-based catalysts. These initiators are essential for starting and controlling the curing or crosslinking reactions of silicone rubber and polyester components. Alternative initiators, such as azo compounds, photoinitiators, or thermal initiators, may also be used depending on the desired curing mechanism and process conditions.

[0073] In addition, the additives may include reinforcing fillers such as silica, carbon black, and calcium carbonate, which are added to improve mechanical strength, durability, and thermal stability. Other silicone rubber additives, such as plasticizers, tackifiers, flame retardants, UV stabilizers, and pigments, may also be included to tailor material properties for specific applications. These additives can influence the material's texture, elasticity, weather resistance, and overall performance, thereby ensuring that it meets the specifications required for its intended use.

[0074] In another aspect, the present invention provides a method for preparing the temperature-adaptive elastic silicone rubber composite material. First, a silicone rubber raw material in liquid or gel form is mixed with additives. Then, a temperature-sensitive elastic polymer is incorporated into the silicone rubber mixture in a predetermined proportion by kneading, thereby ensuring that the polymer is uniformly distributed within the silicone rubber matrix. Finally, the homogenized mixture is molded into the desired shape using injection molding or hot pressing, the process being carried out in a temperature range of 50°C to 190°C, preferably between 100°C and 150°C. Depending on the selected silicone rubber and polymer crosslinking agent, a post-curing step is typically required at approximately 100°C to 150°C for 4 to 20 hours.

[0075] The composite material exhibits a crystallization-melting transition temperature that can be precisely controlled within the range of 10°C to 45°C, preferably 20°C to 40°C.

[0076] The composite material leverages the unique properties of silicone rubber and polyester to achieve an optimal balance between adaptive softness and structural integrity. Upon contact with skin or body surfaces, the polyester component softens at body temperature, allowing the material to precisely conform to the user's unique contours, thereby reducing contact pressure, slippage, or user fatigue. Simultaneously, the composite material maintains its overall rigidity in areas not in direct contact with the body, providing structural stability and durability.

[0077] The composite material exhibits variable hardness characteristics within a specific temperature range while retaining the skin-friendly properties of silicone rubber. This material is specifically designed to adjust its mechanical properties (such as hardness and elasticity) in response to temperature changes, making it suitable for applications with high requirements for temperature sensitivity and comfort, such as wearable technology, medical devices, or consumer products.

[0078] This invention addresses the limitations of traditional silicone rubber materials, which typically exhibit static stiffness and cannot adapt to changes in body temperature or pressure. By combining the adaptive softness of polyester with the structural integrity and tactile texture of silicone rubber, this composite material achieves a balance between comfort and lifespan.

[0079] Furthermore, this material supports environmentally friendly manufacturing practices by incorporating sustainable components, aligning with the growing demand for environmentally conscious solutions in the consumer electronics, medical device, and wearable technology sectors. This makes the invention ideal for high-performance, adaptive, and sustainable wearable applications.

[0080] In the following description, specific details are provided to provide a comprehensive description of various embodiments of the invention for illustrative purposes and are not intended to be limiting.

[0081] Example

[0082] Example 1

[0083] Synthesis and characterization of temperature-sensitive polyesters and their integration in silicone rubber composites

[0084] A temperature-sensitive polyester, UAP03, was synthesized through a multi-step process. First, 72 g of sebacic acid (SbA), 4 g of itaconic acid (IA), 12.8 g of 1,3-propanediol (PDO), 21.6 g of 1,4-butanediol (BDO), and 0.2 g of butylated hydroxytoluene (BHT) were added to a 250 mL three-necked round-bottom flask. Argon gas was then introduced into the flask, and the temperature was gradually increased while mixing. The flask was then placed in an oil bath at 180°C and continuously stirred with a magnetic stirrer to evaporate the water produced by the polycondensation reaction over 2.5 hours. Argon gas was continuously bubbled into the mixture through a syringe needle to maintain an inert atmosphere. After the polycondensation step, the temperature was raised to 220°C, and the catalyst, tetrabutyl titanate (TBT), was added before further heating. Argon gas introduction was stopped, and a vacuum was applied to remove the alcohols and water produced during the transesterification polymerization reaction. The flask was covered with aluminum foil for insulation and a vacuum was maintained for approximately 2 hours. In this final step, the viscosity of the polyester inside the flask increased significantly, indicating successful synthesis and achievement of the expected molecular weight. After the reaction was complete, the heating and vacuum were turned off, and the flask was removed from the oil bath to cool. The polyester mixture was then poured out of the flask, cooled, and weighed. Subsequently, the polyester was blended with a two-component silicone rubber (hardness 20A) at a 1:1 weight ratio using a kneader to ensure thorough mixing. Peroxide was added to the UAP03-silicone rubber mixture to initiate crosslinking between the polyester chains. After thorough mixing, the mixture was molded into 30 x 10 x 3 mm samples using a micro-injection molding machine, with a mold temperature of 150°C and a barrel temperature of 50°C. The samples were cured in the mold for 4 hours, followed by post-curing in an oven at 100°C for 16 hours.

[0085] DSC testing showed that the transition peak temperature of UAP03 was 40°C. DMA measurements at a test frequency of 1Hz showed that the ratio of the elastic modulus at 10°C to that at 40°C was 6.02, indicating that the mechanical modulus is temperature-sensitive. The elastic modulus of UAP03-silicone rubber was 40.1 MPa at 10°C and 6.6 MPa at 40°C. Its Shore A hardness was 58 A at 21°C and 34 A at 40°C, indicating a decrease in hardness of 24 A.

[0086] Example 2

[0087] Synthesis and characterization of temperature-sensitive polyesters and their integration in silicone rubber composites

[0088] A temperature-sensitive polyester, UAP01, was synthesized through a multi-step process. First, 71.8 g of sebacic acid (SbA), 3.6 g of itaconic acid (IA), 16.7 g of 1,3-propanediol (PDO), 19.7 g of 1,4-butanediol (BDO), and 0.294 g of butylated hydroxytoluene (BHT) were added to a 250 mL three-necked round-bottom flask. Argon gas was then introduced into the flask, and the temperature was gradually increased. The flask was then heated in an oil bath at 180°C while stirring with a magnetic stirrer to evaporate the water produced by the polycondensation reaction over 2.5 hours. Argon gas was continuously bubbled into the mixture through a syringe needle to maintain an inert atmosphere. After the polycondensation step, the temperature was raised to 220°C, and the catalyst, tetrabutyl titanate (TBT), was added before further heating. The argon gas flow was stopped, and a vacuum was applied to remove the alcohols and water produced during the transesterification polymerization reaction. The flask was then covered with aluminum foil for insulation and kept under vacuum for approximately 2 hours. In the final step, the viscosity of the polyester inside the flask increased significantly, indicating successful synthesis and achievement of the expected molecular weight.

[0089] After the reaction was complete, heating and vacuum were turned off, and the flask was removed from the oil bath to cool. The polyester mixture was then poured out of the flask, cooled, and weighed. The polyester was then mixed with a two-component silicone rubber (hardness 20A) at a 1:1 weight ratio using a kneader to ensure thorough blending. A small amount of peroxide initiator was added to induce low-degree crosslinking. After thorough mixing, the resulting mixture was molded into 30 x 10 x 3 mm samples using a micro-injection molding machine, with a mold temperature of 150°C and a barrel temperature of 50°C. The samples were then cured in the mold for 4 hours and further post-cured in an oven at 100°C for 16 hours.

[0090] DSC testing showed that the peak transition temperature of UAP01 was 30.2°C, confirming its responsiveness within the physiological temperature range. For the UAP01-silicone rubber composite, DMA measurements at a test frequency of 1Hz showed a modulus ratio of 5.82 between the elastic modulus at 10°C and 40°C, indicating a significant temperature-triggered mechanical transition. The elastic modulus was 15.8 MPa at 10°C and 2.7 MPa at 40°C.

[0091] Furthermore, Shore A hardness testing showed a decrease in hardness from 42A (at 21°C) to 8A (at 40°C), a change of up to 34 units. This more significant decrease in hardness is attributed to the low degree of crosslinking in the polyester matrix. Compared to variants with higher crosslinking, this lower absolute hardness value at temperatures above the transition point is a direct result of the low degree of crosslinking within the UAP01 polyester matrix. While this material achieves excellent anatomical compliance, the low crosslinking density allows for greater mobility of the polymer chains in the softened state. This demonstrates that the hardness gradient and the resulting mechanical response can be precisely tuned by controlling the degree of crosslinking within the composite material.

[0092] Example 3

[0093] Synthesis and characterization of temperature-sensitive polyesters and their integration in silicone rubber composites

[0094] A temperature-sensitive polyester, UAP06, was synthesized through a multi-step process. First, 72 g of sebacic acid (SbA), 1.92 g of itaconic acid (IA), 18.1 g of 1,3-propanediol (PDO), 13.8 g of 1,4-butanediol (BDO), and 0.2 g of butylated hydroxytoluene (BHT) were added to a 250 mL three-necked round-bottom flask. Argon gas was then introduced into the flask, and the temperature was gradually increased. The flask was then heated in an oil bath at 180°C while stirring with a magnetic stirrer to evaporate the water produced by the polycondensation reaction over 2.5 hours. Argon gas was continuously bubbled into the mixture through a syringe needle to maintain an inert atmosphere. After the polycondensation step, the temperature was raised to 220°C, and the catalyst, tetrabutyl titanate (TBT), was added before further heating. The argon gas flow was stopped, and a vacuum was applied to remove the alcohols and water produced during the transesterification polymerization reaction. The flask was then covered with aluminum foil for insulation and kept under vacuum for approximately 2 hours. In the final step, the viscosity of the polyester inside the flask increased significantly, indicating successful synthesis and achievement of the expected molecular weight.

[0095] After the reaction was complete, heating and vacuum were turned off, and the flask was removed from the oil bath to cool. The polyester mixture was then poured out of the flask, cooled, and weighed. Next, the polyester was mixed with a two-component silicone rubber (hardness 20A) at a 1:1 weight ratio using a kneader to ensure thorough blending. No peroxide initiator was added. After thorough mixing, the resulting mixture was molded into 30 x 10 x 3 mm samples using a micro-injection molding machine, with a mold temperature of 150°C and a barrel temperature of 50°C. The samples were then cured in the mold for 4 hours and further post-cured in an oven at 100°C for 16 hours.

[0096] DSC testing revealed that the peak transition temperature of UAP06-silicone rubber was 30.4°C. For the UAP06-silicone rubber composite, DMA measurements at a test frequency of 1 Hz showed a modulus ratio of 64 between 20°C and 50°C. The modulus of elasticity was 37.4 MPa at 20°C and 0.6 MPa at 50°C, confirming the extremely high temperature sensitivity of the mechanical modulus. Further Shore A hardness testing showed a significant decrease in hardness from 65A (at 21°C) to 7A (at 45°C), exhibiting a dramatic drop of 58 units. This anomalous and significant decrease in both modulus of elasticity and hardness is attributed to the lack of a cross-linked network within the UAP06 polyester matrix, resulting in maximum chain mobility at the transition temperature.

[0097] Examples 1, 2, and 3 demonstrate that a wide range of hardness gradients and mechanical transformation characteristics can be designed by precisely controlling the molecular structure of the polyester and the degree of crosslinking within the composite matrix.

[0098] Example 4

[0099] Evaluation of mechanical integrity and durability under cyclic temperature changes

[0100] To verify the durability and long-term performance of the temperature-sensitive composite material, particularly its ability to maintain mechanical integrity under repeated thermal stress, a cyclic heating-cooling study was conducted. The test specimens used were silicone rubber composite materials containing cross-linked polyester (UAP03) and KEG2000-20A / B silicone rubber in a weight ratio of 50 wt%.

[0101] See Figure 4 The sample underwent 30 cycles of repeated heating and cooling over 18 hours. As shown in the “UAP-03 Heating and Cooling Repeated Test Sequence,” the temperature was precisely cycled between approximately 10°C and 70°C. This harsh thermal oscillation represents a demanding environment designed to simulate long-term wear-and-wear scenarios, where materials must repeatedly soften upon contact with the skin and return to their initial state after removal.

[0102] E' was monitored at various frequencies during the first cycle and after the 30th cycle. As summarized in Tables 1 and 2, the elastic modulus values ​​at 25°C and 45°C remained remarkably stable. For example, at a frequency of 1 Hz, the E'(25°C) / E'(45°C) ratio was 2.55 in the first cycle, while it was 2.66 after 30 cycles. These data indicate that the thermally responsive phase transition remained reversible and consistent, and that the crosslinked polymer network did not degrade or lose its temperature sensitivity.

[0103] Table 1

[0104] Table 2

[0105] Further verification was performed using Shore A hardness testing before and after 30 thermal cycles. As shown in Table 3, the composite material maintained a consistent hardness of 58 A at 25°C and a consistent hardness of 32 A at 45°C throughout the testing period.

[0106] Table 3

[0107] Figure 4 The stability results in Tables 1-3 confirm that this dual-phase synergistic structure prevents irreversible deformation or mechanical fatigue. Unlike traditional linear elastomers that may undergo permanent softening, the composite material of this invention maintains its "soft yet firm" (or "soft yet rigid") properties and structural integrity even under cyclic temperature changes.

[0108] Example 5

[0109] Thermal characterization of synthetic polyesters

[0110] To further evaluate the thermodynamic properties of the temperature-sensitive components, the polyesters synthesized in Examples 1, 2, and 3 (UAP03, UAP01, and UAP06, respectively) were analyzed using DSC. This analysis determined the phase transition behavior, which is crucial for ensuring anatomical adaptability at human body temperatures. Measurements, including melting point (T0), were taken during controlled heating-cooling cycles. m ), crystallization temperature (T) c The results include thermal parameters, including the enthalpy change (ΔH) and its corresponding enthalpy change. The results are summarized in Table 4.

[0111] Table 4 - DSC test results of UAP series polyesters

[0112] The DSC data provided in Table 4 lays a quantitative foundation for the excellent thermal response properties of the synthetic polyesters. T values ​​for UAP01, UAP03, and UAP06 were observed. mThe values ​​are 30°C, 40°C, and 30°C, respectively. These values ​​fall precisely within the critical physiological window of 20°C to 40°C, which is crucial for wearable applications that must respond to body temperature. This contrasts sharply with conventional materials such as polycaprolactone (PCL), whose melting points typically exceed 55°C, far beyond the tolerance of the skin. The large enthalpy of fusion (ΔHm) values ​​(ranging from 52 J / g to 60 J / g) indicate a high degree of crystallinity regularity, which is strategically broken only upon reaching the transition temperature. The significant latent heat associated with these transitions ensures a dramatic phase transition process. This high energy density promotes a rapid, nonlinear decrease in hardness and modulus rather than a gradual, slow softening when the material absorbs heat from the body, thus enabling immediate anatomical compliance.

[0113] A comparison of UAP01 and UAP03 further confirms the effectiveness of the molecular engineering described in this invention. By strategically adjusting the alkyl chain length and the ratio of odd to even carbon atoms within the polymer backbone, T can be precisely migrated while maintaining high crystallinity. m (For example, moving from 30°C to 40°C). This level of adjustability allows materials to be customized to specific device needs, such as ear tips that need to soften quickly, or watch straps that require a higher stability threshold.

[0114] T c The temperature range is between 10.5°C and 21°C, ensuring the material remains soft and comfortable upon contact with skin, but recovers its structural stiffness after removal from the body and cooling. Consistent enthalpy of crystallization (ΔH) Tc The values ​​confirm the reversibility and durability of the thermally responsive phase transition. This prevents permanent deformation even after repeated use, validating the dual-phase synergistic structure that maintains mechanical integrity under cyclic temperature variations.

[0115] Comparative Example 1

[0116] Silicone rubber composites based on polycaprolactone

[0117] Commercially available polycaprolactone (PCL) CAPA® 6250, which does not contain unsaturated double bonds for post-crosslinking, was mixed with two-component silicone rubber (hardness 20A) at a 1:1 weight ratio using a kneader. After thorough mixing, the resulting mixture was molded into 30 x 10 x 3 mm specimens using a micro-injection molding machine at a mold temperature of 150°C and a barrel temperature of 50°C. The specimens were then cured in the mold for 4 hours and post-cured in an oven at 100°C for 16 hours.

[0118] The mechanical modulus of the hybrid sample (PCL-silicone rubber) was tested using DMA at test frequencies of 0.1 Hz, 1 Hz, and 10 Hz, revealing a transition temperature of 60-65°C. This transition temperature is outside the human body temperature range. Shore A hardness was measured: 48 A at 25°C, 34 A at 45°C, and 8 A at 60°C. This PCL-silicone rubber composite did not exhibit a hardness transition at human body temperature. Furthermore, at 60°C, the hardness dropped sharply to 8 A, indicating a lack of crosslinking and structural strength.

[0119] This sharp decline, occurring before reaching a stable plateau, directly indicates a lack of cross-linking and insufficient structural strength, leading to structural collapse once the melting point of the linear polyester is reached. Therefore, this traditional PCL-based composite material cannot achieve the synergistic balance between "drastic softening at body temperature" and "structural retention at high temperatures" provided by this invention.

[0120] Comparative Example 2

[0121] In this embodiment, a comparative silicone rubber composite material designated SC09 was prepared using commercially available polycaprolactone (PCL) Ingevity CAPA® 5980 to evaluate its thermal and mechanical properties relative to the synthetic polyester of the present invention.

[0122] Specifically, CAPA® 5980 and two-component silicone rubber (hardness 20A) were mixed in a 1:1 weight ratio using a kneader. The resulting mixture was molded into test specimens and cured under conditions consistent with those described in the foregoing examples.

[0123] The Shore A hardness of SC09 was measured at 25°C, 40°C, and 65°C. As shown in Table 5, the hardness of SC09 was 48 at 25°C, while it only decreased slightly to 47 at 40°C. This indicates that the silicone rubber composite containing commercially available polycaprolactone (PCL) does not exhibit significant softening within the critical physiological window of 20°C to 40°C. Furthermore, when the temperature increased to 65°C, the hardness of SC09 dropped sharply to 8, indicating that the material becomes excessively brittle after reaching its softening point and lacks the structural integrity required for wearable applications. In contrast, the sample containing the synthetic crosslinked polyester of this invention (UAP03) exhibited a controlled transition, with the hardness decreasing from 58 (at 25°C) to 34 (at 40°C), while maintaining a stable hardness of 32 even at 65°C due to its crosslinked network.

[0124] Table 5

[0125] DMA testing further confirmed the insufficient thermal responsiveness of commercially available polyester blends. As summarized in Table 6, SC09 exhibits an E' of 87.0 MPa at 25°C, but this only decreases to 74.4 MPa at 45°C, resulting in a low E'(25) / E'(45°C) ratio of only 1.16. This ratio is significantly lower than that achieved by the present invention (such as UAP03), highlighting the lack of necessary temperature-triggered adaptability in SC09.

[0126] Reference Figure 5 DMA stretching mode scanning of SC09 at multiple frequencies (0.1 Hz, 1 Hz, and 10 Hz) showed that its E' remains relatively high and stable in the range of 20°C to 50°C. The characteristic sharp drop in modulus, representing the phase transition, only occurs between 58°C and 65°C. This transition temperature is far above the tolerance of human skin and the typical body temperature range, rendering it ineffective for adaptive wearable applications.

[0127] Table 6

[0128] Comparative Example 3

[0129] Comparative evaluation of the structural integrity of cross-linked and non-cross-linked polyester-silicone rubber composites

[0130] To further confirm the technical effectiveness of the post-crosslinking network in maintaining structural integrity, a comparative study was conducted on silicone rubber composites containing crosslinked polyester (UAP03) and non-crosslinked polyester (UAP06). Both samples were prepared using KEG2000-20A / B silicone rubber and their respective polyesters at a loading ratio of 50 wt%, with all other process conditions kept completely consistent.

[0131] Shore A hardness was measured at 25°C (room temperature) and 45°C (above the transition point). As summarized in Table 7, although both materials exhibited significant softening, the non-crosslinked composite (UAP06-silicone rubber) showed a dramatic decrease in hardness to only 7 at 45°C. In contrast, the crosslinked composite (UAP03-silicone rubber) maintained a stable hardness of 32 at the same temperature.

[0132] This result indicates that without a cross-linked network, the temperature-sensitive phase becomes excessively soft and fails to provide the necessary mechanical support. The presence of the cross-linked structure in UAP03 ensures that the composite material maintains a state of "soft yet rigid," providing anatomical comfort without sacrificing its functional shape.

[0133] Table 7

[0134] The DMA test results at 1 Hz further confirmed this technical difference. As shown in Table 8, the elastic modulus of the non-crosslinked UAP06-silicone rubber composite material dropped sharply from 36 MPa at 25°C to 0.58 MPa at 45°C, resulting in an E'(25) / E'(45°C) ratio as high as 61.5.

[0135] While such a high ratio indicates extreme sensitivity, an absolute modulus of 0.58 MPa is insufficient for practical wearable applications. Such low stiffness would lead to excessive structural deflection and result in an inability to maintain the tactile texture or firm fit of the device under pressure. In contrast, cross-linked UAP03-silicone rubber maintains a modulus of 10.9 MPa at 45°C, representing a balanced mechanical state that retains elasticity and load-bearing capacity even in a softened state.

[0136] Table 8

[0137] The foregoing description of the invention has been provided for purposes of illustration and description. The foregoing description is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations will be apparent to those skilled in the art.

[0138] The embodiments have been selected and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention with respect to the various embodiments and with various modifications suitable for the intended particular application.

Claims

1. A temperature-sensitive silicone rubber-based composite material, characterized in that, The temperature-sensitive silicone rubber-based composite material includes: 20 to 90 parts by weight of silicone rubber matrix; 10 to 80 parts by weight of a temperature-sensitive elastic polymer, said temperature-sensitive elastic polymer being dispersed in the silicone rubber matrix; and Additives comprising a crosslinking initiator, in amounts of 0.1 to 30 parts by weight. The temperature-sensitive elastic polymer includes an aliphatic unsaturated polyester having a backbone configured to undergo a crystallization-amorphous phase transition within a physiological temperature window of 20°C to 40°C. The silicone rubber matrix and the post-crosslinking network of the aliphatic unsaturated polyester form a biphase synergistic structure, which enables the temperature-sensitive silicone rubber matrix composite material to reduce its Shore A hardness by at least 20 units when it reaches phase transition, while maintaining structural elasticity.

2. The temperature-sensitive silicone rubber-based composite material according to claim 1, wherein the aliphatic unsaturated polyester comprises a polyester structure represented by formula (I): Equation (I), in, R x and R y Each group is independently selected from the following groups: C 1-15 straight-chain alkyl, C 1-15 Branched alkyl groups, and C groups containing at least one carbon-carbon double bond 2-15 Alkenyl group, where m is an integer greater than or equal to 1.

3. The temperature-sensitive silicone rubber-based composite material according to claim 2, wherein R x It includes at least two alkyl components, one having an odd number of carbon atoms and the other having an even number of carbon atoms, configured to regulate the crystalline stacking of the polyester.

4. The temperature-sensitive silicone rubber-based composite material according to claim 2, wherein R y It includes unsaturated aliphatic groups, which are configured to form a post-crosslinking network with the silicone rubber matrix.

5. The temperature-sensitive silicone rubber-based composite material according to claim 1, wherein the temperature-sensitive elastic polymer exhibits a melting enthalpy of at least 50 J / g.

6. The temperature-sensitive silicone rubber-based composite material according to claim 1, wherein the melting temperature of the temperature-sensitive elastic polymer is between 30°C and 40°C.

7. The temperature-sensitive silicone rubber-based composite material according to claim 1, wherein the crystallization temperature of the temperature-sensitive elastic polymer is between 10°C and 21°C.

8. The temperature-sensitive silicone rubber-based composite material according to claim 1, wherein the ratio of the elastic modulus of the temperature-sensitive silicone rubber-based composite material at 10°C to the elastic modulus at 40°C is at least 5.

8.

9. The temperature-sensitive silicone rubber-based composite material according to claim 1, wherein the temperature-sensitive silicone rubber-based composite material exhibits a Shore A hardness variation of 0.1 to 70 units in the temperature range of 10°C to 45°C.

10. The temperature-sensitive silicone rubber-based composite material according to claim 1, wherein the weight-average molecular weight of the temperature-sensitive elastic polymer is in the range of 10 kDa to 100 kDa.

11. The temperature-sensitive silicone rubber-based composite material according to claim 1, wherein the silicone rubber matrix comprises a thermosetting silicone resin selected from the group consisting of polydimethylsiloxane (PDMS) and vinyl-functionalized silicone elastomers.

12. The temperature-sensitive silicone rubber-based composite material according to claim 1, wherein the additives include peroxides, platinum-based catalysts, azo compounds, photoinitiators or thermal initiators, reinforcing fillers or silicone additives.

13. The temperature-sensitive silicone rubber-based composite material according to claim 1, wherein the post-crosslinking network is formed during the molding process by triggering free radical polymerization of unsaturated units within the polyester by the crosslinking initiator.

14. The temperature-sensitive silicone rubber-based composite material according to claim 1, wherein after undergoing at least 30 repeated heating-cooling cycles between 10°C and 70°C, the temperature-sensitive silicone rubber-based composite material retains its Shore A hardness at 45°C.

15. The temperature-sensitive silicone rubber-based composite material according to claim 1, wherein the elastic modulus of the temperature-sensitive silicone rubber-based composite material at 40°C is not less than 2.7 MPa.

16. The temperature-sensitive silicone rubber-based composite material of claim 1, wherein the temperature-sensitive silicone rubber-based composite material is configured as an injection-molded component for a wearable device, the temperature-sensitive silicone rubber-based composite material anatomically conforming to the user's skin surface upon contact with the user's skin.

17. A method for preparing a temperature-sensitive silicone rubber-based composite material, characterized in that, The method includes: Silicone rubber is mixed with additives to form a first mixture; A temperature-sensitive elastic polymer is incorporated into the first mixture to form a second mixture; The second mixture is homogenized by a kneading process under an inert gas atmosphere; and The homogenized mixture is molded into a predetermined shape at a temperature between 100°C and 190°C to simultaneously trigger molding and crosslinking of the temperature-sensitive elastic polymer.

18. The method of claim 17, wherein the method further comprises a post-curing step at a temperature between 100°C and 150°C for 4 to 20 hours.

19. The method of claim 17, wherein the molding process is performed under vacuum conditions to minimize air inclusions and defects within the dual-phase synergistic structure.

20. The method of claim 17, wherein the temperature-sensitive elastic polymer is pre-synthesized from bio-based diols and dicarboxylic acids, and the melting temperature is customized to 20°C to 40°C by adjusting the odd-even carbon ratio in its molecular backbone.

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