Silica gel heating plate and preparation method thereof

Abstract

The invention discloses a silica gel heating plate and a preparation method thereof.The heating plate sequentially comprises a silica gel clinker layer, a first primer layer, a first hot melt adhesive film layer, a heating core layer, a second hot melt adhesive film layer, a second primer layer and a silica gel clinker layer, the silica gel clinker layer is composed of silicone rubber, a filler and a vulcanizing agent, the primer layer is a silane coupling agent, and the hot melt adhesive film layer is a polyamide hot melt adhesive film; the preparation method comprises the steps of primer coating, hot melt adhesive film laminating, heating core laminating, hot press molding and the like, and the effects of good high-temperature resistance, high bonding strength, low cost and the like are achieved by optimizing the material proportion and process parameters.

Description

Technical Field

[0001] This invention provides a silicone heating plate and its preparation method, relating to the field of silicone plate technology. Background Technology

[0002] Silicone heating plates, as a common flexible heating element, have long played an important role in industrial heating, medical equipment, and household appliances. However, traditional silicone heating plates have many inherent defects in structural design, material selection, and manufacturing processes, which seriously restrict their performance and application range. Specifically, traditional silicone heating plates are usually manufactured by combining semi-raw and semi-cooked silicone material with a heating core through a molding and vulcanization process. This structural design can meet basic heating requirements in the initial stage, but with the extension of use time and changes in the usage environment, its inherent problems gradually become apparent: First, the interfacial bonding force between the raw silicone material and the heating core is weak, which easily leads to stress concentration under long-term thermal cycling, resulting in interfacial delamination. This not only affects heating efficiency but may also cause local overheating or even short circuit risks. Second, the temperature resistance of traditional silicone heating plates has a significant bottleneck. Since the heat resistance limit of raw silicone material itself is about 180℃, plus the temperature of the insulating layer... The upper temperature resistance limit of polyimide film is only 220℃, making the entire heating plate unsuitable for high-temperature applications, especially in industrial environments where long-term stable operation above 250℃ is required. Traditional products often exhibit accelerated material aging and significant performance degradation. Furthermore, traditional manufacturing processes are complex and costly, requiring multiple lamination and vulcanization steps, resulting in low production efficiency and unreliable yield. While the addition of reinforcing materials such as fiberglass cloth improves mechanical strength to some extent, it reduces product flexibility, limiting its application in specially shaped equipment. Although some improvements have been attempted in the market, such as adjusting the silicone formula or optimizing vulcanization conditions, none have fundamentally solved the core contradiction of high-temperature delamination and adhesion stability. This makes the development of a new type of silicone heating plate that combines excellent high-temperature performance, good adhesion strength, and reasonable cost an urgent need in the industry and a technical problem that those skilled in the art have long strived to solve without achieving a breakthrough. Summary of the Invention

[0003] To address the aforementioned problems, the present invention provides a silicone heating plate, comprising, in sequence, a silicone curing layer, a first primer layer, a first hot melt adhesive film layer, a heating core layer, a second hot melt adhesive film layer, a second primer layer, and a silicone curing layer, wherein the heating core layer comprises a metal heating wire and an insulating coating layer, the silicone curing layer is composed of silicone rubber, filler, and vulcanizing agent, the primer layer is a silane coupling agent, and the hot melt adhesive film layer is a polyamide hot melt adhesive film.

[0004] Preferably, the silicone rubber in the silicone curing layer is methyl vinyl silicone rubber, the filler is fumed silica, and the vulcanizing agent is dicumyl peroxide, wherein the weight percentage of silicone rubber is 70%-80%, the weight percentage of filler is 15%-25%, and the weight percentage of vulcanizing agent is 1%-5%.

[0005] Preferably, the primer layer is γ-aminopropyltriethoxysilane, and the coating thickness is 0.01 mm to 0.05 mm.

[0006] Preferably, the hot melt adhesive film layer is a polyamide hot melt adhesive film with a thickness of 0.05 mm to 0.2 mm and a melt index of 10 g / 10 min to 50 g / 10 min.

[0007] Preferably, the metal heating wire of the heating core layer is a nickel-chromium alloy wire with a diameter of 0.1 mm to 0.5 mm, and the insulating coating layer is a polyimide film with a thickness of 0.02 mm to 0.1 mm.

[0008] The present invention also provides a method for preparing the above-mentioned silicone heating plate, comprising the following steps: coating a primer on the surface of a silicone curing layer to form a primer layer; attaching a hot melt adhesive film to the surface of the primer layer to form a hot melt adhesive film layer; placing a heating core layer on the surface of the hot melt adhesive film layer; sequentially covering another hot melt adhesive film layer, a primer layer and a silicone curing layer; and performing hot pressing molding.

[0009] Preferably, in the step of applying the primer, the primer is γ-aminopropyltriethoxysilane, the coating method is spraying or brushing, the drying temperature after coating is 80°C to 120°C, and the drying time is 5 min to 10 min.

[0010] Preferably, in the step of bonding the hot melt adhesive film, the hot melt adhesive film is a polyamide hot melt adhesive film, the bonding pressure is 0.1 MPa to 0.5 MPa, and the bonding temperature is 100°C to 150°C.

[0011] Preferably, in the hot pressing step, the hot pressing temperature is 150°C to 200°C, the hot pressing pressure is 0.5MPa to 1.5MPa, and the hot pressing time is 10min to 30min.

[0012] Preferably, the preparation of the silicone curing layer includes mixing methyl vinyl silicone rubber, fumed silica and dicumyl peroxide in a weight ratio of 75:20:5, mixing them evenly on a two-roll mill, with a mixing temperature of 40°C to 60°C and a mixing time of 10 min to 20 min.

[0013] Preferably, the thickness of the silicone curing layer is 0.5mm to 2mm, the thickness of the heating core layer is 0.1mm to 0.5mm, and the total thickness of the overall silicone heating plate is 1.5mm to 4mm.

[0014] Preferably, the hot pressing process further includes a cooling step, wherein the cooling method is natural cooling or forced air cooling, cooling to below room temperature of 25°C.

[0015] Preferably, the melt viscosity of the hot melt adhesive film layer is between 5000 mPa·s and 15000 mPa·s at 150°C.

[0016] Preferably, before applying the primer, the surface of the silicone curd layer is subjected to plasma treatment, with a plasma treatment power of 100W to 300W and a treatment time of 1min to 5min.

[0017] Preferably, the filler further includes alumina, at a weight percentage of 5%-10%, to enhance heat resistance.

[0018] Preferably, the preparation of the heating core layer includes winding a nickel-chromium alloy wire into a serpentine pattern, and then covering it with a polyimide film by hot pressing at a temperature of 180°C to 220°C and a pressure of 0.5 MPa to 1 MPa.

[0019] Preferably, the first primer layer and the second primer layer have the same thickness, both being 0.02 mm to 0.04 mm.

[0020] Preferably, the hot pressing is performed in a vacuum environment with a vacuum degree of -0.1MPa to -0.05MPa.

[0021] Preferably, the Shore A hardness of the silicone curing layer is 50 to 70.

[0022] The beneficial effects of this invention are:

[0023] This invention achieves a comprehensive improvement in the performance of silicone heating plates through innovative material combinations and structural design, specifically manifested in the following significant advancements: First, by employing a novel adhesive system combining a primer and a hot-melt adhesive film, the technical problem of easy delamination in traditional silicone heating plates under high-temperature environments is completely solved. The active silane groups in the primer form a strong chemical bond with the surface of the silicone curing agent, while the hot-melt adhesive film becomes fluid under heating, fully filling the interfacial micropores and forming a three-dimensional network adhesive structure. This dual-protection mechanism significantly improves interlayer bonding strength, preventing delamination even during long-term operation at 280℃. Second, by simplifying the traditional multi-layer composite structure and adopting a symmetrical seven-layer design, this invention not only reduces process complexity and improves production efficiency but also significantly improves the product's flexibility and fit by eliminating rigid materials such as fiberglass cloth, enabling it to adapt to the heating needs of various irregular surfaces. Regarding cost control, due to the adoption of more efficient... With its advanced manufacturing process and optimized material formulation, the production cost of this invention is less than 80% of that of traditional silicone heating plates, while its service life is more than doubled. This improved cost-effectiveness creates favorable conditions for large-scale industrial applications. Furthermore, by precisely controlling the proportions of each component in the silicone curing compound and the hot-pressing process parameters, the consistency and stability of the product are significantly improved. The heat transfer efficiency between the heating core and the silicone layer is enhanced, resulting in a more uniform temperature distribution and preventing localized overheating. Particularly noteworthy is the significant synergistic effect among the primer, hot-melt adhesive film, and silicone curing compound. The primer improves interfacial wettability, the hot-melt adhesive film provides sustained cohesive strength, and the optimized silicone curing compound ensures overall thermal stability and mechanical properties. This multi-component, multi-layered synergistic effect enables the product to achieve breakthroughs in key indicators such as temperature resistance, adhesion strength, and service life, opening up new possibilities for the application of silicone heating plates in demanding industrial environments. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0026] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the experimental materials used in the following examples are all purchased from commercial channels.

[0027] Example 1: Preparation of a silicone curing layer: Methyl vinyl silicone rubber (75 parts by weight), fumed silica (20 parts by weight), and dicumyl peroxide (5 parts by weight) were mixed on a two-roll mill at 50°C for 15 min to form a sheet with a thickness of 1 mm; the surface of the silicone curing layer was subjected to plasma treatment at 200 W for 3 min; γ-aminopropyltriethoxysilane was coated as a primer with a thickness of 0.03 mm and dried at 100°C for 8 min; a polyamide hot melt adhesive film (0.1 mm thick, melt index 3) was then laminated onto the film. 0g / 10min), bonding pressure 0.3MPa, temperature 120℃; a nickel-chromium alloy wire (diameter 0.2mm) is wound into a serpentine pattern, covered with a polyimide film (thickness 0.05mm) to form a heating core layer, placed on a hot melt adhesive film, covered with another hot melt adhesive film layer and a primer layer, and covered with another silicone curing layer; the whole thing is hot-pressed in a hot press at 180℃ and 1.0MPa pressure for 20min, vacuum degree -0.08MPa, and then naturally cooled to room temperature after hot pressing to obtain a silicone heating plate with a total thickness of 2.5mm.

[0028] Example 2: Preparation of a silicone curing layer: Methyl vinyl silicone rubber (70 parts by weight), fumed silica (25 parts by weight), and dicumyl peroxide (5 parts by weight) were mixed on a two-roll mill at 60°C for 10 min to form a sheet with a thickness of 1.5 mm. The surface of the silicone curing layer was subjected to plasma treatment at 200 W for 3 min. γ-aminopropyltriethoxysilane was then coated as a primer to a thickness of 0.01 mm and dried at 120°C for 5 min. A polyamide hot melt adhesive film (0.0 mm thick) was then laminated onto the film. The bonding pressure is 0.1 MPa and the temperature is 150℃. A nickel-chromium alloy wire (diameter 0.1 mm) is wound into a serpentine pattern, covered with a polyimide film (thickness 0.02 mm) to form a heating core layer, placed on a hot melt adhesive film, covered with another hot melt adhesive film layer and a primer layer, and covered with another silicone curing layer. The whole thing is hot-pressed in a hot press at 200℃ and 0.5 MPa pressure for 30 min. After hot pressing, it is air-cooled to room temperature to obtain a silicone heating plate with a total thickness of 3.0 mm.

[0029] Example 3: Preparation of a silicone curing layer: Methyl vinyl silicone rubber (80 parts by weight), fumed silica (15 parts by weight), alumina (5 parts by weight), and dicumyl peroxide (3 parts by weight) were mixed on a two-roll mill at 40°C for 20 min to form a sheet with a thickness of 0.5 mm. The surface of the silicone curing layer was subjected to plasma treatment at 200 W for 3 min. γ-aminopropyltriethoxysilane was then coated as a primer to a thickness of 0.05 mm and dried at 80°C for 10 min. A polyamide hot melt adhesive film (0.2 mm thick) was then laminated onto the film. The heating element is formed by winding a 0.5mm diameter nickel-chromium alloy wire into a serpentine pattern, covering it with a 0.1mm thick polyimide film to form the heating core layer, placing it on a hot melt adhesive film, covering it with another hot melt adhesive film layer and a primer layer, and finally covering it with another silicone curing layer. The entire assembly is then hot-pressed in a hot press at 150℃ and 1.5MPa pressure for 10 minutes, with a vacuum degree of -0.1MPa. After hot pressing, it is naturally cooled to room temperature to obtain a silicone heating plate with a total thickness of 1.5mm.

[0030] Comparative Example 1 uses a traditional silicone heating plate process. The structure consists of a silicone curing layer, a fiberglass cloth layer, a silicone raw material layer, a heating core layer, a silicone raw material layer, a fiberglass cloth layer, and a silicone curing layer. The silicone curing layer is made by mixing methyl vinyl silicone rubber (70 parts by weight), fumed silica (25 parts by weight), and dicumyl peroxide (5 parts by weight) on a two-roll mill at 50°C for 15 minutes to form a sheet with a thickness of 1 mm. The silicone raw material layer is semi-cured silicone (with the same composition as the curing layer but not fully vulcanized). The fiberglass cloth is 0.1 mm thick. The heating core layer is made by winding nickel-chromium alloy wire (0.2 mm in diameter) into a serpentine pattern and covering it with a polyimide film (0.05 mm thick). After stacking, the heating plate is vulcanized in a molding press at 170°C and 1.0 MPa pressure for 20 minutes without a vacuum environment and naturally cooled to room temperature, resulting in a silicone heating plate with a total thickness of 2.5 mm.

[0031] Comparative Example 2 omits the primer layer. The structure consists of a silicone curing layer, a hot melt adhesive film layer, a heating core layer, a hot melt adhesive film layer, and a silicone curing layer. The silicone curing layer is prepared in the same way as in Example 1. 75 parts by weight of methyl vinyl silicone rubber, 20 parts by weight of fumed silica, and 5 parts by weight of dicumyl peroxide are mixed at 50°C for 15 minutes to form a 1mm thick sheet. The surface of the silicone curing layer is subjected to plasma treatment at 200W for 3 minutes. A polyamide hot melt adhesive film with a thickness of 0.1mm and a melt index of 30g / 10min is directly bonded to it at a bonding pressure of 0.3MPa and a temperature of 120°C. The heating core layer consists of a nickel-chromium alloy wire (0.2mm in diameter) wrapped with a polyimide film (0.05mm in thickness). After lamination, the layers are hot-pressed at 180°C and 1.0MPa pressure for 20 minutes, with a vacuum degree of -0.08MPa. The layers are then naturally cooled to room temperature, resulting in a silicone heating plate with a total thickness of 2.5mm.

[0032] Comparative Example 3 uses traditional raw silicone material instead of hot melt adhesive film. The structure consists of a silicone curing layer, a primer layer, a silicone raw material layer, a heating core layer, a silicone raw material layer, a primer layer, and a silicone curing layer. The silicone curing layer is the same as in Example 1, consisting of 75 parts by weight of methyl vinyl silicone rubber, 20 parts by weight of fumed silica, and 5 parts by weight of dicumyl peroxide. These are mixed at 50°C for 15 minutes to form a 1mm thick sheet. The primer is γ-aminopropyltriethoxysilane with a coating thickness of 0.03mm. The sheet is dried at 100°C for 8 minutes. The silicone raw material layer is semi-cured silicone (with the same composition as the curing layer, but not fully vulcanized). The heating core layer consists of a nickel-chromium alloy wire (0.2mm in diameter) wrapped with a polyimide film (0.05mm thick). After lamination, the layers are hot-pressed at 180°C and 1.0MPa pressure for 20 minutes, with a vacuum degree of -0.08MPa. The layers are then naturally cooled to room temperature, resulting in a silicone heating plate with a total thickness of 2.5mm.

[0033] Comparative Example 4 omits the hot melt adhesive film layer and uses only a primer as the adhesive layer. The structure consists of a silicone curing layer, a primer layer, a heating core layer, a primer layer, and a silicone curing layer. The silicone curing layer is the same as in Example 1, consisting of 75 parts by weight of methyl vinyl silicone rubber, 20 parts by weight of fumed silica, and 5 parts by weight of dicumyl peroxide. These are mixed at 50°C for 15 minutes to form a sheet with a thickness of 1 mm. The primer is γ-aminopropyltriethoxysilane with a coating thickness of 0.03 mm. The sheet is dried at 100°C for 8 minutes. The heating core layer consists of a nickel-chromium alloy wire (0.2 mm in diameter) wrapped with a polyimide film (0.05 mm in thickness). After lamination, the layers are hot-pressed at 180°C and 1.0 MPa for 20 minutes under a vacuum of -0.08 MPa. The layers are then naturally cooled to room temperature to obtain a silicone heating plate with a total thickness of 2.5 mm.

[0034] Comparative Example 5 omits the plasma treatment step, directly coating a primer and bonding a hot melt adhesive film. The silicone curing layer is the same as in Example 1. 75 parts by weight of methyl vinyl silicone rubber, 20 parts by weight of fumed silica, and 5 parts by weight of dicumyl peroxide are mixed at 50°C for 15 minutes to form a 1mm thick sheet. Without plasma treatment, γ-aminopropyltriethoxysilane is directly coated as a primer with a thickness of 0.03mm. It is dried at 100°C for 8 minutes and then bonded with a polyamide hot melt adhesive film with a thickness of 0.1mm and a melt index of 30g / 10min. The bonding pressure is 0.3MPa and the temperature is 120°C. The heating core layer is a nickel-chromium alloy wire (0.2mm in diameter) wrapped with a polyimide film (0.05mm thick). After lamination, it is hot-pressed at 180°C and 1.0MPa pressure for 20 minutes with a vacuum degree of -0.08MPa and naturally cooled to room temperature to obtain a silicone heating plate with a total thickness of 2.5mm.

[0035] Comparative Example 6 used unoptimized hot-pressing parameters: hot-pressing temperature 120℃, pressure 0.2MPa, time 5 minutes, without a vacuum environment. The silicone curing layer was the same as in Example 1. 75 parts by weight of methyl vinyl silicone rubber, 20 parts by weight of fumed silica, and 5 parts by weight of dicumyl peroxide were mixed at 50℃ for 15 minutes to form a 1mm thick sheet. The surface of the silicone curing layer was subjected to plasma treatment at 200W for 3 minutes. γ-aminopropyltriethoxysilane was then coated as a primer. The coating thickness is 0.03 mm, and it is dried at 100℃ for 8 minutes. Then, a polyamide hot melt adhesive film with a thickness of 0.1 mm and a melt index of 30 g / 10 min is laminated. The lamination pressure is 0.3 MPa and the temperature is 120℃. The heating core layer is a nickel-chromium alloy wire (diameter 0.2 mm) wrapped with a polyimide film (thickness 0.05 mm). After lamination, it is hot-pressed at 120℃ and 0.2 MPa pressure for 5 minutes without vacuum. It is then naturally cooled to room temperature to obtain a silicone heating plate with a total thickness of 2.5 mm.

[0036] Comparative Example 7 used a different material combination. The primer was a common silane coupling agent, methyltrimethoxysilane, and the hot melt adhesive film was an EVA-based hot melt adhesive film with a melt index of 40 g / 10 min. The silicone curing layer was the same as in Example 1. 75 parts by weight of methyl vinyl silicone rubber, 20 parts by weight of fumed silica, and 5 parts by weight of dicumyl peroxide were mixed at 50°C for 15 minutes to form a 1 mm thick sheet. The surface of the silicone curing layer was subjected to plasma treatment at 200 W for 3 minutes, followed by coating with a common silane coupling agent. The bonding agent was used as a primer, with a coating thickness of 0.03 mm. It was dried at 100°C for 8 minutes, followed by the lamination of an EVA hot melt adhesive film with a thickness of 0.1 mm at a lamination pressure of 0.3 MPa and a temperature of 120°C. The heating core layer consisted of a nickel-chromium alloy wire (0.2 mm in diameter) and a polyimide film (0.05 mm in thickness). After lamination, the film was hot-pressed at 180°C and 1.0 MPa pressure for 20 minutes with a vacuum degree of -0.08 MPa. It was then allowed to cool naturally to room temperature, resulting in a silicone heating plate with a total thickness of 2.5 mm.

[0037] Comparative Example 8 omits the vacuum environment and performs hot pressing under normal pressure. The silicone curing layer is the same as in Example 1. 75 parts by weight of methyl vinyl silicone rubber, 20 parts by weight of fumed silica, and 5 parts by weight of dicumyl peroxide are mixed at 50°C for 15 minutes to form a 1mm thick sheet. The surface of the silicone curing layer is subjected to plasma treatment at 200W for 3 minutes. γ-aminopropyltriethoxysilane is coated as a primer with a thickness of 0.03mm and dried at 100°C for 8 minutes. Subsequently, a polyamide hot melt adhesive film with a thickness of 0.1mm and a melt index of 30g / 10min is laminated at a bonding pressure of 0.3MPa and a temperature of 120°C. The heating core layer consists of a nickel-chromium alloy wire (0.2mm in diameter) and a polyimide film (0.05mm in thickness). After lamination, the heating plate is hot-pressed at 180°C and 1.0MPa for 20 minutes, then cooled naturally to room temperature to obtain a silicone heating plate with a total thickness of 2.5mm.

[0038] Comparative Example 9: The material ratio of the silicone curing layer was changed. 85 parts by weight of methyl vinyl silicone rubber, 10 parts by weight of fumed silica, and 5 parts by weight of dicumyl peroxide were mixed on a two-roll mill at 50°C for 15 minutes to produce a 1mm thick sheet with a Shore A hardness of approximately 75. The surface of the silicone curing layer was then subjected to plasma treatment at 200W for 3 minutes. γ-aminopropyltriethoxysilane was then coated as a primer to a thickness of 0.03mm and dried at 100°C. After drying for 8 minutes, a polyamide hot melt adhesive film with a thickness of 0.1 mm and a melt index of 30 g / 10 min is laminated. The lamination pressure is 0.3 MPa and the temperature is 120 °C. The heating core layer consists of a nickel-chromium alloy wire (0.2 mm in diameter) and a polyimide film (0.05 mm in thickness). After lamination, the film is hot-pressed at 180 °C and 1.0 MPa pressure for 20 minutes with a vacuum degree of -0.08 MPa. The film is then allowed to cool naturally to room temperature, resulting in a silicone heating plate with a total thickness of 2.5 mm.

[0039] Comparative Example 10 uses a conventional heating element with an insulation layer of ordinary polyethylene film, resistant to 120°C and 0.05mm thick, replacing the polyimide film. The silicone curing layer is the same as in Example 1, consisting of 75 parts by weight of methyl vinyl silicone rubber, 20 parts by weight of fumed silica, and 5 parts by weight of dicumyl peroxide, mixed at 50°C for 15 minutes to form a 1mm thick sheet. The surface of the silicone curing layer is then subjected to plasma treatment at 200W for 3 minutes, followed by coating with γ-aminopropyltriethoxysilane as a primer. The coating thickness is 0.03mm, and it is dried at 100℃ for 8 minutes. Then, a polyamide hot melt adhesive film with a thickness of 0.1mm and a melt index of 30g / 10min is laminated. The lamination pressure is 0.3MPa and the temperature is 120℃. The heating core layer is a nickel-chromium alloy wire (diameter 0.2mm) covered with ordinary polyethylene film. After lamination, it is hot-pressed at 180℃ and 1.0MPa pressure for 20 minutes with a vacuum degree of -0.08MPa. It is then naturally cooled to room temperature to obtain a silicone heating plate with a total thickness of 2.5mm.

[0040] The products obtained in the above embodiments and comparative examples were tested using the following methods, and the results are shown in Table 1.

[0041] Temperature resistance test: The sample was cut into 100mm×100mm pieces, fixed on the high-temperature test chamber bracket, and connected to a K-type thermocouple to monitor the temperature. The temperature was increased from room temperature to 300℃ at a rate of 5℃ / min, and held for 10min for every 10℃ increase. The appearance of the sample was checked for delamination, and the heating core was checked for short circuit or failure. The failure temperature was recorded. Adhesion strength test: Using a universal tensile testing machine, the sample was cut into 25mm wide strips and a 180° peel test was performed at a rate of 100mm / min. The maximum peel force was recorded and divided by the width to calculate the strength (N / mm). Each sample was tested 3 times and the average value was taken. Life test: The sample was placed in a 250℃ environmental chamber with a rated voltage of 220V and operated continuously. It was checked every 500 hours and the time until the heating core burned out, the silicone layer delaminated, or the performance decreased to 80% of the initial value was recorded. Cost ratio calculation: The material and production cost of the traditional silicone heating plate (Comparative Example 1) was used as a benchmark of 100%. The cost of this invention was calculated based on the amount of material used, process time, and equipment loss. All materials were commercially available industrial grade.

[0042]

[0043] The temperature resistance, adhesion strength, lifespan, and cost-effectiveness of Examples 1-3 of this invention are significantly better than all comparative examples, while the performance parameters of Comparative Examples 1-10 are generally lower, especially Comparative Examples 1 and 10, which are the worst, indicating that traditional methods cannot solve the problems of high-temperature delamination and adhesion. The temperature resistance and adhesion strength of Comparative Examples 2 and 4 are significantly reduced, proving that the primer and hot melt adhesive film are indispensable in enhancing interfacial adhesion and high-temperature stability, and that the synergistic effect of the two is necessary to achieve the best results. Although the performance of Comparative Examples 5 and 8 is partially close to that of the examples, it is still insufficient, indicating that plasma treatment and vacuum environment can further improve adhesion uniformity and product consistency. The performance of Comparative Examples 6 and 7 is also poor, indicating the necessity of optimizing parameters and specific material combinations. Comparative Example 9 shows that material ratio deviation will lead to increased hardness and shortened lifespan, further verifying the importance of the ratio range in the scheme of this invention. Overall, this invention achieves a comprehensive improvement in the performance of silicone heating plates through the synergy of primer, hot melt adhesive film, plasma treatment, vacuum hot pressing, and optimized material ratio, combined with material combination and structural design.

[0044] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0045] The present invention and its embodiments have been described above. This description is not restrictive, but merely one embodiment of the present invention, and the actual application is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar methods and embodiments without departing from the spirit of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A silicon heating plate characterized by, The silicone rubber layer, the first primer layer, the first hot melt adhesive film layer, the heating core layer, the second hot melt adhesive film layer, the second primer layer and the silicone rubber layer are sequentially arranged, wherein the heating core layer comprises a metal heating wire and an insulating coating layer, the silicone rubber layer is composed of silicone rubber, filler and vulcanizing agent, the primer layer is a silane coupling agent, and the hot melt adhesive film layer is a polyamide hot melt adhesive film.

2. The silicone heating pad of claim 1, wherein, The silicone rubber in the silicone rubber layer is methyl vinyl silicone rubber, the filler is fumed silica, and the vulcanizing agent is dicumyl peroxide, wherein the weight percentage of the silicone rubber is 70%-80%, the weight percentage of the filler is 15%-25%, and the weight percentage of the vulcanizing agent is 1%-5%.

3. The silicone heating pad of claim 1, wherein, The primer layer is γ-aminopropyl triethoxysilane, and the coating thickness is 0.01mm to 0.05mm.

4. The silicone heating pad of claim 1, wherein, The hot melt adhesive film layer is a polyamide hot melt adhesive film, the thickness is 0.05mm to 0.2mm, and the melt index is 10g / 10min to 50g / 10min.

5. The silicone heating pad of claim 1, wherein, The metal heating wire of the heating core layer is a nickel-chromium alloy wire with a diameter of 0.1mm to 0.5mm, and the insulating coating layer is a polyimide film with a thickness of 0.02mm to 0.1mm.

6. A method of producing the silicon heating plate according to any one of claims 1 to 5, characterized by, The method comprises the following steps: The primer layer is formed by coating the primer on the surface of the silicone rubber layer, and the hot melt adhesive film layer is formed by laminating the hot melt adhesive film on the surface of the primer layer, the heating core layer is placed on the surface of the hot melt adhesive film layer, and another hot melt adhesive film layer, a primer layer and a silicone rubber layer are sequentially covered and hot-pressed.

7. The production method according to claim 6, characterized by, In the step of coating the primer, the primer is γ-aminopropyl triethoxysilane, the coating method is spraying or brushing, the drying temperature after coating is 80℃ to 120℃, and the drying time is 5min to 10min.

8. The preparation method according to claim 6, characterized in that, In the step of laminating the hot melt adhesive film, the hot melt adhesive film is a polyamide hot melt adhesive film, the lamination pressure is 0.1MPa to 0.5MPa, and the lamination temperature is 100℃ to 150℃.

9. The preparation method according to claim 6, characterized in that, In the step of hot pressing, the hot pressing temperature is 150℃ to 200℃, the hot pressing pressure is 0.5MPa to 1.5MPa, and the hot pressing time is 10min to 30min.

10. The method of claim 6, wherein, The preparation of the silicone rubber layer comprises mixing methyl vinyl silicone rubber, fumed silica and dicumyl peroxide in a weight ratio of 75:20:5, uniformly mixing on an open mill, and mixing at a temperature of 40℃ to 60℃ for 10min to 20min.

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