A composite thermal and electrical insulation structure suitable for radio frequency sealing and plasma ablation

Abstract

The application discloses a composite heat insulation structure suitable for radio frequency sealing and plasma ablation, and relates to the field of electrosurgical instruments. The composite heat insulation structure is arranged in a non-working area of a surgical clamp and is used for limiting heat diffusion and non-target conduction in a multi-energy working condition. The composite heat insulation structure comprises a first functional layer and a second functional layer. The first functional layer is arranged outside a metal base of the surgical clamp and is used for limiting heat and current diffusion to the non-working area in a radio frequency sealing working condition. The second functional layer is arranged outside the first functional layer and is used for improving the electrical insulation stability in a wet environment in a plasma ablation working condition. The composite heat insulation structure is designed in layers and is matched with differentiated functional layers, and is specifically adapted to different working condition requirements of radio frequency sealing and plasma ablation, so that the pain point that a single structure cannot simultaneously consider high-temperature heat insulation and wet-state insulation is effectively solved.

Description

Technical Field

[0001] This invention relates to electrosurgical instrument technology, specifically to a composite thermal insulation structure suitable for radiofrequency blocking and plasma ablation. Background Technology

[0002] In the field of minimally invasive electrosurgery, radiofrequency ablation and plasma ablation techniques have become the most widely used energy surgical techniques in clinical practice due to their unique technical advantages. Radiofrequency ablation primarily relies on bipolar radiofrequency energy to act on the target tissue, causing rapid denaturation of proteins and contraction and fusion of collagen fibers, thereby achieving vascular closure, tissue sealing, and effective hemostasis. It features high closure strength, ease of operation, and wide applicability, and is widely used in minimally invasive surgeries such as general surgery, obstetrics and gynecology, and urology. Plasma ablation, on the other hand, typically operates in a conductive liquid environment such as saline. It uses a radiofrequency electric field to excite the electrolyte to form a low-temperature plasma layer. High-energy particles break tissue molecular bonds, completing tissue cutting, ablation, and trimming in a low-temperature, minimally invasive, and precise manner. It causes minimal thermal damage to surrounding normal tissue and provides a clear surgical field, making it particularly suitable for delicate laparoscopic procedures and soft tissue manipulation.

[0003] As minimally invasive surgery rapidly evolves towards multifunctionality and integration, clinical practice demands higher levels of complexity in surgical instruments. Currently, the same electrosurgical instrument often requires the alternating, switching, or even overlapping use of radiofrequency ablation and plasma ablation energy modes during the same surgical procedure to simultaneously perform a series of complex operations such as hemostasis, tissue closure, cutting, ablation, and trimming, thereby improving surgical efficiency, shortening operation time, and optimizing treatment outcomes. However, the two energy modes differ significantly in their working environment, energy transfer methods, thermal behavior, and electric field distribution, which places more stringent and complex technical requirements on the thermal insulation and electrical insulation performance of surgical instruments.

[0004] Current traditional electrosurgical instruments mostly employ a simple structural design with a single insulating or heat-insulating layer. Their core purpose is merely to limit energy diffusion to non-working areas to a certain extent, reducing damage to non-target tissues. For example, traditional radiofrequency blocking instruments typically use coating, spraying, encapsulation, or injection molding to create insulating layers of ceramic, PTFE, PEEK, silicone, or conventional polymers on the surface of a metal substrate, attempting to partially block heat conduction along the metal substrate. Traditional plasma surgical instruments mostly rely on a single insulating coating on the surface to block current conduction in non-working areas, preventing abnormal arcing and energy leakage. Such single-layer structures can barely achieve basic insulation or heat insulation functions under single energy and single operating conditions, but their technical defects and safety hazards become particularly prominent under the combined conditions of radiofrequency and plasma energy.

[0005] First, the adaptability to different operating conditions is severely inadequate. Radiofrequency sealing is a dry, high-temperature, and high-heat-flux-density process. The heat generated by the surgical energy is easily conducted rapidly along the metal substrate to the non-working area of ​​the instrument, causing excessively high local temperatures, which can burn surrounding normal tissue and increase the risk of postoperative complications. Conversely, plasma ablation is a wet, high-electric-field-strength process. Conductive liquids such as blood and electrolytes can form continuous conductive paths on the instrument surface, easily leading to the failure of traditional insulation layers and problems such as unexpected discharge, energy leakage, and localized arcing. Existing single-layer structural material systems are limited and cannot simultaneously achieve both high-temperature insulation in the dry state and high-reliability insulation in the wet state, making it difficult to adapt to the complex requirements of using both energy modes simultaneously.

[0006] Secondly, they have poor adaptability to complex structures. Modern minimally invasive electrosurgical forceps generally have complex structural forms such as steerable joints, multi-curvature surfaces, assembly gaps, and transition fillets. Traditional coating, overlay, or injection-molded single-layer insulation / heat insulation layers are difficult to achieve continuous, uniform, and complete coverage of complex curved surfaces, gaps, and joints. This often results in problems such as discontinuous coatings, low adhesion strength, localized thinness, and susceptibility to cracking due to bending fatigue. These defects can directly create preferential heat diffusion channels or weak points for electric field breakdown at joints, transition areas, and gaps, significantly reducing the safety and structural durability of the instrument under cyclic use under multiple operating conditions.

[0007] Secondly, long-term stability and reliability are insufficient. Under the combined effects of high temperature, high electric field, liquid immersion, mechanical friction, and repeated bending, single insulating or thermal insulation materials are prone to aging, embrittlement, delamination, peeling, decreased dielectric properties, and reduced breakdown strength, leading to a gradual decline in thermal and electrical insulation performance. This performance degradation is characterized by its insidious nature and rapid development, directly increasing safety risks such as intraoperative thermal damage, insulation breakdown, and abnormal discharge, making it difficult to meet the high reliability and long service life requirements of modern surgical instruments.

[0008] In summary, existing technologies lack a composite thermal insulation structure that can simultaneously adapt to radio frequency blocking and plasma ablation, balance thermal insulation and electrical insulation, and be suitable for complex structures and various operating conditions. Summary of the Invention

[0009] The purpose of this invention is to provide a composite thermal insulation structure suitable for radio frequency sealing and plasma ablation, so as to solve the problem that the single insulation / thermal insulation structure of existing multi-energy integrated surgical instruments cannot be adapted to both the dry high temperature of radio frequency sealing and the wet high electric field of plasma ablation, and has poor adaptability to complex structures.

[0010] To achieve the above objectives, the present invention provides the following technical solution: a composite thermal insulation structure suitable for radio frequency blocking and plasma ablation, wherein the composite thermal insulation structure is disposed in the non-working area of ​​surgical forceps and is used to limit heat diffusion and non-target conductivity under multi-energy conditions, the composite thermal insulation structure comprising:

[0011] The first functional layer is located on the outside of the metal substrate of the surgical forceps and is used to limit the diffusion of heat and current to the non-working area under radio frequency closed conditions. The first functional layer is made of ceramic-filled polyimide material.

[0012] The second functional layer, covering the outside of the first functional layer, is used to improve the electrical insulation stability in a humid environment under plasma ablation conditions. The second functional layer is made of perfluoroalkoxy resin.

[0013] Furthermore, the second functional layer is a conformal insulating layer that continuously covers the curved surfaces, gaps, or turning joints of the surgical forceps surface to form a seamless insulating barrier at each location.

[0014] Furthermore, the composite thermal insulation structure also includes at least one intermediate functional layer disposed between the first functional layer and the second functional layer. This intermediate functional layer, serving as a performance transition zone, has a material composition and physical properties intermediate between the first and second functional layers. It is used to alleviate interfacial stress caused by the difference in thermal expansion coefficients between the two layers, and simultaneously participates in constructing a performance gradient in the thickness direction, enabling a smooth transition rather than abrupt changes in thermal conductivity and dielectric strength. This improves the interfacial bonding reliability of the composite structure under temperature cycling and mechanical deformation.

[0015] Furthermore, the composite thermal insulation structure has a gradient structure with varying performance in the thickness direction. The gradient structure is configured such that, along the direction away from the metal substrate, the filler gradient distribution / interlayer parameters of the composite thermal insulation structure transition step by step. The first functional layer forms a thermal resistance gradient region through the filler distribution in the thickness direction. When the intermediate functional layers are included, the thermal and dielectric parameters of each layer transition step by step along the thickness direction.

[0016] Furthermore, the composite thermal insulation structure features differentiated layered configurations in different functional areas of the surgical forceps. These differentiated layered configurations include:

[0017] The first region, corresponding to the non-working surface of the jaws, has a composite thermal insulation structure with high thermal resistance and high dielectric strength; the ceramic filler mass fraction of the first functional layer in the composite thermal insulation structure is 65-70%, the ceramic filler particle size is 2-5μm, and the thickness ratio of the first functional layer to the second functional layer is 4-7:1.

[0018] The second region, corresponding to the steering joint or curved surface structure, has a composite thermal insulation structure with high conformability and high wet insulation resistance. In the composite thermal insulation structure, the ceramic filler mass fraction of the first functional layer is 20-25%, the ceramic filler particle size is 0.5-1μm, the porosity of the second functional layer is 25-30%, and the thickness ratio of the first functional layer to the second functional layer is 1.5-2.5:1.

[0019] Furthermore, the edges of the composite thermal insulation structure are continuous transition edges to reduce electric field concentration and heat accumulation in the edge region. Specifically, the distance between the edge of the composite thermal insulation structure and the geometric boundary of the metal substrate 4 of the surgical forceps is 0 to 0.05 mm, and the edge end is provided with a sloping transition section with a thickness gradually decreasing to zero, the length of which is 0.1 to 0.5 mm.

[0020] Furthermore, the composite thermal insulation structure is formed onto the metal substrate by overlay spraying and melt-flowing.

[0021] Furthermore, the second functional layer is a perfluoroalkoxy resin layer with a micro-closed-pore structure.

[0022] Compared with existing technologies, this invention provides a composite thermal insulation structure suitable for radiofrequency blocking and plasma ablation. On one hand, through a layered design with differentiated functional layers, it specifically adapts to the different operating conditions of radiofrequency blocking and plasma ablation, effectively solving the problem that a single structure cannot simultaneously provide high-temperature thermal insulation and wet insulation, thus meeting the clinical requirements of multi-energy integrated surgical instruments. On the other hand, by optimizing the structural configuration and molding method, it adapts to complex structures such as curved surfaces, gaps, and steering joints of surgical forceps, ensuring the safety, stability, and durability of the instrument. Specific technical effects include the following:

[0023] 1. It can effectively reduce the heat transfer from the metal substrate to the outer surface of the non-working area under the closed dry high temperature condition of radio frequency, reduce the risk of tissue thermal damage caused by the temperature rise of the non-working area, and form a stable insulating barrier under the wet high electric field condition of plasma ablation, inhibit the formation of conductive path in liquid medium, and avoid safety hazards such as energy leakage and arc discharge.

[0024] 2. Adapts to the complex structure of surgical forceps, achieving continuous and complete coverage of the insulation and heat insulation layer, reducing problems such as discontinuous coverage, poor adhesion, bending, and cracking, and improving the structural reliability and service life of the instrument during repeated use.

[0025] 3. Through the interlocking design of the interface between the first functional layer and the second functional layer (plasma activation treatment allows PFA melt to penetrate into the microstructure of the polyimide surface), the interlayer bonding strength is significantly enhanced, the interface durability of the composite structure under repeated bending, temperature cycling and liquid immersion conditions is improved, and interlayer delamination failure is effectively avoided.

[0026] 4. The micro-closed-pore structure of the second functional layer works synergistically with the low surface energy of PFA to significantly improve the volume resistivity in a wet environment. It maintains high insulation after being soaked in physiological saline, ensuring long-term reliability under the wet high electric field conditions of plasma ablation. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0028] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0029] Figure 2 This is a schematic diagram of the structure of Embodiment 2 of the present invention;

[0030] Figure 3 This is a schematic diagram of the structure of Embodiment 3 of the present invention.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1. First functional layer; 2. Second functional layer; 3. Intermediate functional layer; 4. Metal substrate; 5. First region; 6. Second region. Detailed Implementation

[0033] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0034] As attached Figure 1 As shown:

[0035] Example 1:

[0036] The present invention provides a composite thermal insulation structure suitable for radio frequency blocking and plasma ablation. The composite thermal insulation structure is disposed in the non-working area of ​​the surgical forceps and is used to limit heat diffusion and non-target conductivity under multi-energy conditions. The composite thermal insulation structure includes: a first functional layer 1 and a second functional layer 2.

[0037] 1. In one embodiment of the present invention, a first functional layer 1 is disposed on the outside of the metal substrate 4 of the surgical forceps to limit the diffusion of heat and current to the non-working area under radio frequency closed conditions.

[0038] 2. In one embodiment of the present invention, the second functional layer 2 covers the outside of the first functional layer 1 and is used to improve the electrical insulation stability in a humid environment under plasma ablation conditions. The second functional layer 2 is a conformal insulating layer that continuously covers the curved surfaces, gaps, or turning joints of the surgical forceps surface to form a seamless insulating barrier at each location.

[0039] 3. In one embodiment of the present invention, the first functional layer 1 is made of ceramic-filled polyimide material, and its total thickness is 120 μm. In order to achieve synergistic control of thermal and electric fields, the ceramic filler (alumina particle size distribution of 1-3 μm) inside the first functional layer 1 is distributed in a continuous gradient along the thickness direction.

[0040] 4. In one embodiment of the present invention, the second functional layer 2 is made of perfluoroalkoxy resin, and the thickness of the second functional layer 2 is 30 μm. To further improve wet insulation, this layer is prepared by adding a closed-cell nucleating agent (0.5% by mass of polytetrafluoroethylene micro powder) to form a uniformly distributed micro-closed-cell structure during the preparation process. The porosity is controlled at 15-20%, and the pore size is ≤5 μm. This micro-closed-cell structure reduces the equivalent dielectric constant of the material on the one hand, and on the other hand, through the blocking effect of micropores on the water molecule permeation path, it ensures that the volume resistivity remains ≥5×10 after immersion in physiological saline for 24 hours. 15 Ω·cm. The second functional layer 2 continuously covers the curved surfaces, gaps, or turning joints of the surgical forceps surface to form a seamless insulating barrier at each location.

[0041] 5. In one embodiment of the present invention, the bonding reliability between the first functional layer 1 and the second functional layer 2 is enhanced by an interface interlocking structure. The interface interlocking structure is formed as follows: before the second functional layer 2 is sprayed and molded, the surface of the cured first functional layer 1 is subjected to plasma activation treatment to generate nanoscale micro-pits and introduce polar groups on its surface; subsequently, the sprayed perfluoroalkoxy resin melt penetrates into the micro-pits, and after curing, an anchor bolt interlocking effect is formed. Testing shows that after adopting this interface interlocking structure, the interlayer bonding strength is increased from 5.2 MPa without treatment to 12.8 MPa.

[0042] 6. In one embodiment of the present invention, the thickness ratio of the first functional layer 1 to the second functional layer 2 is 4:1, the difference in dielectric constant (difference value 2.1), and the aforementioned gradient filler and microporous structure together construct a thermoelectric dual-field control mechanism. Under radio frequency sealing conditions, the filler concentration gradient from high to low inside the first functional layer 1 allows heat flow to be gradually dissipated during penetration, preventing heat accumulation at the interface. Under plasma ablation conditions, the second functional layer 2 with low dielectric constant undertakes the main withstand voltage task, while the first functional layer 1 with high dielectric constant plays a role in equalizing the voltage. At the same time, the micro-closed-pore structure of the second functional layer 2 effectively blocks the conductive path in a humid environment.

[0043] Working principle: Implementation Example 1 achieves composite protection of the non-working area of ​​the surgical forceps under multiple energy conditions through the functional synergy and working condition adaptive characteristics of the first functional layer 1 and the second functional layer 2, adapting to the usage requirements of dual working conditions of radio frequency sealing and plasma ablation.

[0044] Under radio frequency closed conditions, the first functional layer 1 serves as the main protective layer. Relying on its low thermal conductivity, it effectively reduces the conduction of heat along the metal substrate 4 of the surgical forceps to the non-working area. At the same time, it uses its high dielectric strength to limit the disordered diffusion of current, achieving efficient heat insulation and precise current limiting in dry high-temperature environments, avoiding thermal damage to non-target tissues and the risk of misdirected electrical current.

[0045] Under plasma ablation conditions, the second functional layer 2, made of perfluoroalkoxy resin with a thickness of 10-50 μm, serves as the main protective layer. Utilizing its excellent hydrophobic properties and high volume resistivity, it repels conductive liquids in wet environments such as body fluids, cutting off unintended conductive pathways. Its conformal structure design can closely fit complex parts such as the curved surface, gaps, and turning joints of surgical forceps, forming a continuous and unbroken insulation barrier, effectively preventing local insulation breakdown or arc generation, and ensuring insulation stability under wet conditions.

[0046] As attached Figure 2 As shown:

[0047] Example 2:

[0048] This embodiment is basically the same as the previous embodiment, except that the composite thermal insulation structure further includes at least one intermediate functional layer 3 disposed between the first functional layer 1 and the second functional layer 2. The intermediate functional layer 3 serves as a performance transition zone, with its material composition and physical properties falling between the first functional layer 1 and the second functional layer 2. It is used to alleviate the interfacial stress caused by the difference in thermal expansion coefficients between the two layers, and simultaneously participates in constructing the performance gradient in the thickness direction, enabling a smooth transition rather than a step change in thermal conductivity and dielectric strength, thereby improving the interfacial bonding reliability of the composite structure under temperature cycling and mechanical deformation.

[0049] 1. In one embodiment of the present invention, the composite thermal insulation structure has a gradient structure with a performance gradient change in the thickness direction. The gradient structure is configured such that the filler gradient distribution / interlayer parameters of the composite thermal insulation structure gradually transition along the direction away from the metal substrate 4.

[0050] 2. In one embodiment of the present invention, due to the significant difference in surface energy between the first functional layer 1 and the second functional layer 2, direct composite bonding may lead to insufficient interlayer adhesion. The intermediate functional layer 3 can be made of polyetheretherketone (PEEK) or its composite material. PEEK material has the characteristics of high temperature resistance, good dielectric properties, and good compatibility with both PI and PFA, which can effectively alleviate the interfacial stress caused by the difference in thermal expansion coefficient and surface energy between the two layers. In addition, the intermediate functional layer 3 participates in constructing the performance gradient in the thickness direction, so that the thermal conductivity and dielectric strength achieve a smooth transition rather than a step change, thereby improving the interfacial bonding reliability of the composite structure under temperature cycling and mechanical deformation. The ceramic filler mass fraction of the intermediate functional layer 3 is 15-20%, and the thickness is 25 μm. The relative permittivity of the intermediate functional layer 3 is 3.2-3.5, and the thermal conductivity is 0.28 W / m·K, which are exactly between the performance parameters of the first functional layer 1 (outer layer) and the second functional layer 2.

[0051] 3. In one embodiment of the present invention, the intermediate functional layer 3 is formed with the adjacent layers using a semi-cured superposition co-sintering process: when the first functional layer 1 is in a semi-cured state, a slurry of the intermediate functional layer 3 is coated. Subsequently, during the heating process, the interfacial molecular chains of the two resin layers undergo interdiffusion, and after curing, a compositional gradient transition region with a thickness of approximately 2-3 μm is formed. Similarly, the intermediate functional layer 3 and the second functional layer 2 also form an intermixed interface through superposition in a semi-cured state. This interfacial mixing eliminates the interlayer interface, avoiding the interfacial charge accumulation caused by abrupt changes in dielectric constant in traditional multilayer structures. At the same time, the gradient transition of the coefficient of thermal expansion significantly reduces the risk of thermal stress cracking under temperature cycling.

[0052] Working Principle: Based on Example 1, Example 2 introduces at least one intermediate functional layer 3 between the first functional layer 1 and the second functional layer 2, constructing a composite structure with a performance gradient along the thickness direction, thus achieving synergistic optimization of thermal and electrical properties. Compared to the two-layer structure of Example 1, Example 2 reduces interlayer interface stress through continuous performance transition, improving the reliability of the structure under temperature changes and mechanical bending; simultaneously, it eliminates protection blind spots during operating condition switching, providing more stable and durable thermal insulation protection under multi-energy operating conditions.

[0053] In Example 2, the composite thermal insulation structure exhibits a three-level gradient change in the thickness direction:

[0054] First functional layer 1 (close to the metal substrate 4): dielectric constant 4.2, filler gradient 55-30%;

[0055] Intermediate functional layer 3: dielectric constant 3.2-3.5, filler content 15-20%;

[0056] Second functional layer 2: dielectric constant 2.1, porosity 15-20%.

[0057] Along the direction away from the metal substrate 4, the first functional layer 1 forms a thermal resistance gradient region through the filler distribution in the thickness direction; when the intermediate functional layer 3 is included, the thermal and dielectric parameters of each layer gradually transition along the thickness direction.

[0058] As attached Figure 3 As shown:

[0059] Example 3:

[0060] This embodiment is basically the same as the previous embodiment, except that the composite thermal insulation structure has differentiated layered structure configurations in different functional areas of the surgical forceps. The differentiated layered structure configurations include:

[0061] Region 5, corresponding to the non-working surface of the jaws: This region mainly bears high-temperature heat conduction, therefore its composite thermal insulation structure adopts a high filler load design. The mass fraction of ceramic filler on the inner side of the first functional layer 1 is increased to 65-70% (coarse powder with a particle size of 2-5μm is selected to form a denser thermally conductive barrier network), and the thickness ratio of the first functional layer 1 to the second functional layer 2 is adjusted to 6:1 (the thickness of the first functional layer 1 is 150μm, and the thickness of the second functional layer 2 is 25μm) to maximize the thermal barrier capability against the metal substrate 4.

[0062] The second region, 6, corresponds to the steering joint or curved surface structure. This region primarily faces challenges from liquid wetting and mechanical bending; therefore, its composite thermal insulation structure employs a design with high flexibility and high wet-state insulation. The ceramic filler mass fraction of the first functional layer 1 is reduced to 20-25% (fine powder with a particle size of 0.5-1μm is selected to reduce damage to the matrix toughness), while the porosity of the second functional layer 2 is increased to 25-30% to enhance the flexibility and wet-state insulation resistance of the joint area. The thickness ratio of the first functional layer 1 to the second functional layer 2 is adjusted to 2:1.

[0063] 1. In one embodiment of the present invention, the edge of the composite thermal insulation structure is a continuous transition edge to reduce electric field concentration and heat accumulation in the edge region. Specifically, the distance between the edge of the composite thermal insulation structure and the geometric boundary of the metal substrate 4 of the surgical forceps is 0 to 0.05 mm, and the edge end is provided with a slope transition section with a thickness gradually decreasing to zero, the length of which is 0.1 to 0.5 mm.

[0064] Working Principle: Since different parts of the surgical forceps have significantly different requirements for heat insulation, the non-working surfaces of the jaws primarily bear the brunt of high-temperature heat conduction, while complex structures such as the steering joints face the dual challenges of liquid immersion and mechanical deformation. Therefore, Embodiment 3 achieves on-demand adaptation of protective performance through a regionally differentiated layered structure configuration. Through zoned differentiated configuration and boundary definition, Embodiment 3 achieves a three-dimensional protective system that provides focused protection for critical areas and reliable coverage for complex areas, enhancing the structural reliability of the instrument under multi-posture operation and multi-energy conditions.

[0065] In Embodiments 1, 2, and 3 above, the composite thermal insulation structure is formed onto the metal substrate 4 through conformal spraying and melt-flowing. Specific steps include:

[0066] Step 1: Substrate pretreatment. The surface of the metal substrate 4 of the surgical forceps is roughened by sandblasting to increase the surface roughness and adhesion area; then ultrasonic degreasing and cleaning is performed to remove oil and impurities, and the substrate is thoroughly dried at 80-120℃.

[0067] Step Two: Contouring spraying of the first functional layer 1. The ceramic-filled polyimide precursor solution is loaded into the spraying equipment. The spraying parameters are adjusted (spray gun pressure 0.4–0.6 MPa, spraying distance 15–25 cm). Contouring spraying is performed on the pretreated metal substrate 4 surface, ensuring coverage of curved surfaces, gaps, and complex areas such as steering joints. After each coat, bake at 150–200℃ for 5–10 minutes, repeating 3–5 times until a uniform thickness of 50–200 μm is achieved. Finally, cure at 300–350℃ for 2–4 hours.

[0068] Step 3: Second functional layer 2: Contouring spraying and melt leveling. Perfluoroalkoxy resin (PFA) powder or dispersion is loaded into the spraying equipment and used for conformal spraying on the surface of the first functional layer 1. For complex areas such as steering joints and curved surfaces, the spray gun angle is adjusted to ensure continuous, uninterrupted coverage. After each coat, the temperature is raised to 250–300°C for melt leveling, allowing the PFA material to fully spread and form a dense conformal layer. This spraying and melt leveling process is repeated 2–3 times until a uniform conformal layer of 10–50 μm is formed.

[0069] Step Four: Post-processing and Inspection. The formed composite structure is annealed under gradually decreasing temperature to eliminate internal stress. Subsequently, thickness measurement, electrical breakdown testing, and thermal imaging analysis are performed to ensure the performance of the composite thermal insulation structure meets design requirements. Simultaneously, heat accumulation monitoring is conducted on the metal substrate 4, simulating long-term operating conditions (80W power, 60 seconds). The temperature rise curve of the metal substrate 4 is monitored in real time to ensure its temperature remains below the safe threshold of 60℃ within the set time. This prevents heat from accumulating inside the substrate through the insulation structure, thus avoiding the risk of unexpected thermal damage due to prolonged operation.

[0070] Combining the composite thermal insulation structure provided in Embodiments 1, 2, and 3 above, through layered gradient design and regional differentiated configuration, it achieves synergistic protection under dual conditions of radio frequency blocking and plasma ablation. Its key performance is verified by the following reproducible experiments, specifically including:

[0071] Test conditions:

[0072] project Specification Test ambient temperature 23±2℃ Test ambient humidity 50±5% RH physiological saline concentration 0.9% NaCl (medical grade) Number of samples Five samples were collected in each group, and the results were taken as the mean ± standard deviation. Comparative Example Single polyimide insulating layer (120μm thick) Test equipment High resistance meter, pull-out adhesion tester, infrared thermal imager, dielectric strength tester

[0073] Performance test results:

[0074] Test Project Example 1 Example 2 Example 3 Comparative Example Wet volume resistivity (Ω·cm) <![CDATA[(5.32±0.18)×10 15 ]]> <![CDATA[(6.15±0.22)×10 15 ]]> <![CDATA[First region: (5.08 ± 0.20) × 10 15 ; Second region: (4.85 ± 0.25) × 10 15 > <![CDATA[(2.12±0.19)×10 12 ]]> Interlayer bond strength (MPa) 12.76±0.26 15.32±0.31 Region 1: 12.53±0.28; Region 2: 11.28±0.35 5.20±0.15 Thermal barrier performance (temperature rise in 60 seconds, °C) 28±2 24±2 Region 1: 21±2; Region 2: 35±3 56±3 Dry-state breakdown voltage (kV) 8.2±0.4 9.1±0.3 Region 1: 8.5±0.4; Region 2: 7.6±0.3 6.5±0.3 Wet breakdown voltage (kV) 6.8±0.3 7.5±0.3 Region 1: 7.0 ± 0.3 Region 2: 6.2 ± 0.4 2.1±0.4

[0075] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A composite thermal insulation structure suitable for radio frequency blocking and plasma ablation, wherein the composite thermal insulation structure is disposed in the non-working area of ​​surgical forceps and is used to limit heat diffusion and non-target conductivity under multi-energy conditions, characterized in that, The composite thermal insulation structure includes: The first functional layer (1) is disposed on the outside of the metal substrate (4) of the surgical forceps and is used to limit the diffusion of heat and current to the non-working area under radio frequency closed conditions. The first functional layer (1) is made of ceramic-filled polyimide material. The second functional layer (2) covers the outside of the first functional layer (1) and is used to improve the electrical insulation stability in a wet environment under plasma ablation conditions. The second functional layer (2) is made of perfluoroalkoxy resin. An interface interlocking structure is provided between the first functional layer (1) and the second functional layer (2); The composite thermal insulation structure has a gradient structure with performance gradient changes in the thickness direction. The gradient structure is configured such that the filler gradient distribution / interlayer parameters of the composite thermal insulation structure gradually transition along the direction away from the metal matrix (4). The composite thermal insulation structure has a differentiated layered structure configuration in different functional areas of the surgical forceps, specifically including: The first region (5) corresponds to the non-working surface of the jaws. The ceramic filler mass fraction of the first functional layer (1) in its composite thermal insulation structure is 65-70%, the ceramic filler particle size is 2-5μm, and the thickness ratio of the first functional layer (1) to the second functional layer (2) is 4-7:

1. The second region (6) corresponds to the steering joint or curved surface structure. In its composite thermal insulation structure, the ceramic filler mass fraction of the first functional layer (1) is 20-25%, the ceramic filler particle size is 0.5-1μm, the porosity of the second functional layer (2) is 25-30%, and the thickness ratio of the first functional layer (1) to the second functional layer (2) is 1.5-2.5:

1.

2. The composite thermal insulation structure suitable for radio frequency blocking and plasma ablation according to claim 1, characterized in that, The second functional layer (2) is a shaped insulating layer that continuously covers the curved surfaces, gaps, or turning joints of the surgical forceps to form a seamless insulating barrier at each location.

3. The composite thermal insulation structure suitable for radio frequency blocking and plasma ablation according to claim 1, characterized in that, The composite thermal insulation structure also includes at least one intermediate functional layer (3) disposed between the first functional layer (1) and the second functional layer (2).

4. A composite thermal insulation structure suitable for radio frequency blocking and plasma ablation according to claim 3, characterized in that, The intermediate functional layer (3) is made of polyetheretherketone material.

5. A composite thermal insulation structure suitable for radio frequency blocking and plasma ablation according to claim 1, characterized in that, The distance between the edge of the composite thermal insulation structure and the geometric boundary of the metal substrate (4) surface of the surgical forceps is 0 to 0.05 mm, and the edge end is provided with a slope transition section with a thickness gradually decreasing to zero, the length of the slope transition section being 0.1 to 0.5 mm.

6. A composite thermal insulation structure suitable for radio frequency sealing and plasma ablation according to claim 1, characterized in that, The second functional layer (2) is a perfluoroalkoxy resin layer with a micro-closed-pore structure.

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