Cooking bench oil separation film and preparation method thereof

Abstract

The invention relates to the technical field of high-temperature-resistant protective materials for kitchens, in particular to a cooking bench oil separation film and a preparation method thereof. The problem that an existing cooking bench oil separation film is prone to yellowing, embrittling and losing elasticity at the high temperature for a long time is solved. A four-layer gradient thermal management design is adopted, the first layer is a working surface layer, polyetherimide (PEI) is used as matrix resin, and modified nano boron nitride and nano cerium oxide filler are dispersed; the second layer is a main heat insulation layer, organic silicon resin is adopted as a matrix, and hollow glass beads and silicon dioxide powder are added to improve the heat insulation strength; the third layer is a flexible buffer layer and adopts an organic silicon elastomer containing a foaming agent to form a microporous structure; the fourth layer is an intelligent adhesion layer, an organic silicon pressure-sensitive adhesive is adopted, modified thermal expansion microspheres are doped, and the adhesiveness is automatically reduced at the high temperature; all the layers are firstly formed respectively and then prepared through low-temperature lamination and co-curing; the oil separation film provided by the invention has excellent aging resistance and stability at long-term high temperature.

Description

Technical Field

[0001] This invention relates to the field of high-temperature resistant protective materials for kitchens, specifically to a stovetop grease barrier and its preparation method. Background Technology

[0002] Household kitchen stovetops are frequently exposed to splattering oil and high temperatures during daily cooking. To protect the stovetop surface from grease buildup, grease-blocking films or protective mats are typically used. However, existing grease-blocking film materials are prone to aging after a period of use in high-temperature environments, manifesting as yellowing, brittleness, and decreased elasticity and adhesion. This is mainly due to the thermo-oxidative aging of commonly used polymer materials under prolonged high temperatures and oily fumes.

[0003] The most common types of oil-proof coatings for stovetops on the market are as follows: One type is Teflon-coated fiberglass cloth gaskets, which are characterized by being non-stick to oil and resistant to certain high temperatures. When these gaskets are near an open flame or exceed their temperature resistance range, the polytetrafluoroethylene (PTFE) coating will gradually degrade, resulting in problems such as discoloration, hardening, or even the release of harmful fumes. After long-term use, the fiberglass substrate may also become brittle or delaminate due to high temperatures.

[0004] Secondly, there are silicone pads or silicone rubber coatings as protective films. Silicone rubber materials have excellent heat resistance and elasticity, and can withstand higher temperatures for a short period of time. However, ordinary silicone pads may still show signs of aging after prolonged use in the high-temperature area of ​​the stove, such as yellowing, loss of elasticity, or even hardening and cracking. This is due to further cross-linking or oxidation of the silicone at high temperatures. In addition, silicone pads have low thermal conductivity but limited heat insulation effect. Increasing the thickness will affect their softness and conformability. After a period of use, their bottom adhesion will also decrease, making them prone to curling or shifting.

[0005] Thirdly, metal films such as aluminum foil gaskets, although resistant to high temperatures, have high thermal conductivity and cannot provide thermal insulation and cushioning. They are also mainly for single use and have poor environmental protection and aesthetics.

[0006] In summary, existing grease-separating film materials for cooktops are insufficient in terms of long-term stability under high temperatures and heat insulation performance, making it difficult to simultaneously achieve high heat resistance without aging, good heat insulation, and necessary flexible adhesion. Therefore, there is an urgent need for a new type of grease-separating protective film material that will not yellow or crack after long-term use in the high-temperature environment of the cooktop, and that also possesses excellent heat insulation and anti-scalding properties as well as continuous adhesion and flexibility. Summary of the Invention

[0007] This invention provides a stovetop grease barrier film and its preparation method, aiming to significantly improve the stability of the grease barrier film under long-term high-temperature environment, so that it does not turn yellow or become brittle after being subjected to high-temperature oil fume impact, and maintains good elasticity and adhesion performance; at the same time, it improves the heat insulation and protection effect, protecting the stovetop surface from high-temperature scorching.

[0008] The specific technical solution is as follows: A stovetop grease barrier and its preparation method are as follows: S1: Raw material preparation and pretreatment.

[0009] S11: Nano-boron nitride and nano-cerium oxide are dispersed in an ethanol aqueous solution and ultrasonically dispersed to obtain a suspension; silane coupling agent KH-550 is added to the suspension, mechanically stirred, cooled to room temperature, centrifuged, washed, vacuum dried, and ground to obtain a surface-modified nanocomposite filler; thermally expanded microspheres are added to an ethanol aqueous solution and stirred to obtain a suspension; silane coupling agent KH-901 is added to the suspension, then the temperature is raised to 55℃ and mechanically stirred, centrifuged, washed, and vacuum dried to obtain modified thermally expanded microspheres.

[0010] S12: Add PEI powder to N-methylpyrrolidone (NMP) and stir at 65°C until completely dissolved to obtain a PEI solution; premix the surface-modified nanocomposite filler prepared in S11, antioxidant 1010, dispersant BYK-163 with N-methylpyrrolidone to obtain a premixed slurry; add the premixed slurry to the PEI solution, stir, grind, and degas to obtain the working surface layer slurry.

[0011] S13: Mix the organosilicon resin and solvent N-methylpyrrolidone evenly, add rheology modifier BYK-410, stir and add hollow glass microspheres and silica powder, then perform vacuum degassing to obtain the main insulation layer slurry.

[0012] S14: Mix the two-component liquid silicone rubber with the foaming agent azodicarbonamide and stir to obtain a flexible buffer layer compound.

[0013] S15: Add the modified thermally expandable microspheres to the high-temperature resistant silicone pressure-sensitive adhesive and stir to obtain the smart adhesion layer colloid.

[0014] S2: Preliminary preparation and curing.

[0015] S21: The working surface layer slurry prepared in S12 is coated onto the PET release film and then dried to obtain a semi-dry working surface layer; the microstructure is imprinted onto the semi-dry working surface layer, and then cured by UV irradiation, cooled to room temperature, and wound up to obtain the working surface layer film.

[0016] S22: The main heat insulation layer slurry prepared in S13 is coated onto the polyimide film, then cured by step heating, cooled, and wound up to obtain the main heat insulation layer film.

[0017] S23: The flexible buffer layer adhesive prepared in S14 is coated onto the PET release film, then cured by step heating, cooled, and wound up to obtain the flexible buffer layer film.

[0018] S24: The smart adhesive layer colloid prepared in S15 is coated onto the corona-treated PET release film, and then cured, cooled, wound up, and aged to obtain the smart adhesive layer film.

[0019] S3: Processing and preparation.

[0020] S31: Remove the PET release film from the flexible buffer layer film prepared in S22, and perform plasma treatment on the surfaces that need to be bonded to the main heat insulation layer film prepared in S21.

[0021] S32: Remove the PET release film from the working layer film prepared in S21, and stack it with the main heat insulation layer film and flexible buffer layer film treated by plasma in S31 through the alignment and stacking rollers. Then, irradiate it with UV to obtain a pre-cured composite film. The pre-cured composite film is heated in stages through a hot press, and finally cooled and cured by cooling rollers to obtain a semi-finished composite film.

[0022] S33: The flexible buffer layer of the semi-finished composite film prepared in S32 is lightly pressed and laminated with the smart adhesive layer film at room temperature, then wound up and cured to obtain an oil-separating film.

[0023] Furthermore, in the ethanol-water solution described in S11, the volume ratio of ethanol to water is 4:1.

[0024] The mass ratio of the nano-boron nitride and nano-cerium oxide described in S11 to the volume ratio of the ethanol aqueous solution is 1:20 to 1:50.

[0025] The ultrasonic dispersion described in S11 has the following parameter settings: power 600-800W, on 2s / off 1s, duration 30-60min.

[0026] The KH-550 described in S11 has a mass of 1.5 to 3.0% of the total weight of the nanofiller.

[0027] The mechanical stirring described in S11 has the following parameters: 300-500 rpm, temperature 65-75℃, and duration 4-6 h.

[0028] The washing described in S11 involves alternating between anhydrous ethanol and deionized water, washing three times each.

[0029] The vacuum drying described in S11 has the following parameters: vacuum degree -0.085MPa, temperature 80℃, and duration 24h.

[0030] Furthermore, the premixing described in S12 has the following parameter settings: rotation speed 10000 rpm, duration 15 min.

[0031] The degassing process described in S12 has the following parameter settings: vacuum degree -0.095MPa, duration 25min.

[0032] The working surface slurry described in S12 is based on 100 parts of PEI resin, with the following material proportions: 350-450 parts of N-methylpyrrolidone, 15-25 parts of surface-modified nanocomposite filler, 0.5-3 parts of antioxidant 1010, and 1-3 parts of BYK-163.

[0033] Furthermore, the main insulation layer slurry described in S13 uses 100 parts of organosilicon resin as the matrix, and the proportions of each material are as follows: solvent N-methylpyrrolidone 150-250 parts, hollow glass microspheres 30-50 parts, silica powder 10-20 parts, and BYK-410 0.5-2 parts.

[0034] Furthermore, the flexible buffer layer material described in S14 uses 100 parts of two-component liquid silicone rubber as a base and 2 to 5 parts of azodicarbonamide as a foaming agent.

[0035] Furthermore, the smart adhesive layer colloid described in S15 is based on 100 parts of high-temperature resistant silicone pressure-sensitive adhesive, with 5 to 15 parts of modified thermal expansion microspheres.

[0036] Furthermore, the drying process described in S21 has the following parameters: temperature 80-90°C, duration 1-2 min.

[0037] The microstructure described in S21 is an antiphase micropapillary array structure.

[0038] The UV irradiation described in S21 has the following parameter settings: wavelength 365nm, intensity 1500mW / cm². 2 Exposure time: 1 second.

[0039] The thermosetting parameters described in S21 are: temperature 200~220℃, duration 10~20min.

[0040] Furthermore, the step heating described in S22 has the following parameter settings: first zone temperature 80-100℃, duration 5-10min; second zone temperature 130-150℃, duration 5-10min; third zone temperature 180-200℃, duration 15-30min.

[0041] Furthermore, the stepped heating described in S23 has the following parameter settings: the temperature of the first zone is 80-100℃, the duration is 5-10 min, the temperature of the second zone is 150-170℃, the duration is 3-5 min, and the temperature of the third zone is 180-200℃, the duration is 5-10 min.

[0042] Furthermore, the curing parameters described in S24 are set as follows: temperature 60-80°C, duration 5-10 min, and aging parameters are set as follows: temperature 25°C, duration 24 h.

[0043] Furthermore, the plasma treatment described in S31 has the following parameter settings: power 500-1500W, treatment gas is air, and treatment speed 1-5m / min.

[0044] Furthermore, the pressure setting for the lamination described in S32 is 1 N / cm. 2 .

[0045] The UV irradiation described in S32 has the following parameters: wavelength 395nm, intensity 500~1000mW / cm². 2 Exposure time is 3-10 seconds.

[0046] The hot press described in S32 has the following parameter settings: roller gap 1 temperature 80~100℃, linear pressure 10~20N / cm, residence time 10~20s; roller gap 2 temperature 120~140℃, linear pressure 30~50N / cm, residence time 20~40s; roller gap 3 temperature 160~180℃, linear pressure 20~30N / cm, residence time 10~20s.

[0047] Furthermore, the light pressure described in S33 has a pressure parameter of 3 N / cm.

[0048] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention uses PEI and modified nanofillers in the working surface layer to delay the thermo-oxidative aging process of the material under high temperature environment, and significantly improves its resistance to yellowing and embrittlement.

[0049] 2. This invention achieves a smooth thermal transition from the high-temperature working surface to the low-temperature adhesion surface through a four-layer functional design. The composite filler system of the main insulation layer works synergistically to ensure that the temperature of the adhesive layer is always below its tolerance limit.

[0050] 3. This invention effectively relieves stress through a flexible buffer layer, and the lamination and co-curing process ensures the interlayer bonding strength, so that the film as a whole does not crack or delaminate during thermal cycling.

[0051] 4. This invention achieves strong adhesion and easy removal without residue through an intelligent adhesive layer, thus improving the user experience. Attached Figure Description

[0052] Figure 1 This is a process flow diagram for the preparation of an oil-separating membrane for stovetops.

[0053] Figure 2 This is a schematic diagram of the oil-separating film in Example 1.

[0054] Figure 3 These are thermal images of the back equilibrium temperature of the oil-separating films finally prepared in Examples 1-4 and Comparative Examples 1-3 under a 250°C heat source.

[0055] Figure 4 This is a comparison chart of the elongation at break and tensile strength retention rates of the oil-separating films finally prepared in Examples 1-4 and Comparative Examples 1-3.

[0056] Figure 5 This is a comparison chart of the thermal conductivity and back-side equilibrium temperature data of the oil-separating films finally prepared in Examples 1-4 and Comparative Examples 1-3 under a 250°C heat source. Detailed Implementation

[0057] The following embodiments further explain and illustrate the technical solutions of the present invention. It should be specifically noted that each specific embodiment is a concretization and explanation of the technical solution and should not be considered as a limitation on the scope of protection of the present invention. Those skilled in the art still have the right to modify the technical solutions of these embodiments and make equivalent substitutions for some or all of the technical features, and these modifications or substitutions do not change the essence of the corresponding technical solutions, nor do they cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions described in the present invention.

[0058] This invention proposes a stovetop grease barrier and its preparation method, employing a four-layer gradient thermal management design: the first layer is the working surface layer, using PEI as the base resin, dispersing modified nano-boron nitride and nano-cerium oxide fillers, and adding antioxidants to enhance high-temperature resistance and anti-aging properties; the second layer is the main heat insulation layer, using silicone resin as the base, adding hollow glass microspheres and silica powder to improve heat insulation strength; the third layer is a flexible buffer layer, using silicone elastomer containing foaming agents to form a microporous structure; the fourth layer is an intelligent adhesion layer, using silicone pressure-sensitive adhesive and incorporating modified thermally expandable microspheres to automatically reduce adhesion at high temperatures; each layer is first molded separately, and then bonded together by low-temperature lamination and curing. (See attached image) Figure 1 The image shows a method for preparing an oil-separating film for a stovetop, and its detailed technical solution is as follows: 1. Raw material preparation and pretreatment Surface modification: Nano-boron nitride and nano-cerium oxide are modified because nanoparticles have a large specific surface area and high surface energy, making them prone to aggregation. Untreated nanofillers cannot be uniformly dispersed in organic polymer matrices, forming stress defects and impairing material properties. Silane coupling agents can build a strong bridge between inorganic fillers and organic resins through grafting, improving compatibility and interfacial bonding. Thermally expandable microspheres with an initial expansion temperature above 90℃ and an optimal expansion temperature of around 120℃ are selected. This is because the surface temperature around the stove is typically between 50℃ and 80℃, far below the microsphere's trigger temperature. Therefore, the heat from normal cooking is insufficient to activate the microspheres, maintaining stable adhesion and preventing the film from detaching on its own. The thermally expandable microspheres are modified with KH901 to improve their heat resistance and solvent resistance in silicone adhesives.

[0059] Working layer preparation: PEI is used as the base resin, with dispersed modified nano-boron nitride and nano-cerium oxide fillers, and antioxidants are added to enhance high-temperature resistance and anti-aging properties. PEI resin forms a high-temperature resistant continuous phase. N-methylpyrrolidone dissolves PEI, adjusting viscosity. The modified composite filler enhances thermal conductivity and anti-aging properties, while the antioxidant provides synergistic antioxidant effects. BYK-163 prevents nanoparticles from re-aggregating and settling through steric hindrance or electrostatic repulsion. The working layer preparation is performed simultaneously with imprinting and UV irradiation. During imprinting, a specific wavelength of UV light is used to rapidly and initially cure the surface resin, accurately replicating and fixing the micro / nano structure, forming a working layer with superoleophobic potential.

[0060] Preparation of the main insulation layer: Using silicone resin as the matrix, hollow glass microspheres, silica powder, and BYK-410 are added. The hollow glass microspheres and silica powder work synergistically to provide insulation. BYK-410 forms a three-dimensional network structure in the slurry, significantly increasing the viscosity at low shear rates, thus effectively preventing the sedimentation of denser fillers such as hollow glass microspheres and ensuring uniformity during coating. The main insulation layer preparation step aims to create an intermediate layer with excellent insulation performance and certain mechanical strength. The foaming agent decomposes at 130–150℃, forming a uniform and closed microporous structure. The silicone resin is then completely cross-linked and cured at 180–200℃ to form a final stable foam.

[0061] Flexible buffer layer preparation: A microporous structure is formed using an organosilicon elastomer containing a foaming agent. Its main function is to absorb the stress caused by thermal expansion and contraction between the stovetop and the membrane, preventing the membrane from lifting or peeling off, while also improving tactile comfort. At 150–170℃, azodicarbonamide rapidly decomposes to produce nitrogen gas. Since the silicone rubber has already undergone preliminary cross-linking, the gas is encapsulated, forming a uniform closed-cell foam structure. At 180–200℃, the silicone rubber completely completes the cross-linking reaction, and the foam structure is fully fixed.

[0062] Preparation of the smart adhesive layer: An organosilicon pressure-sensitive adhesive was used, incorporating modified thermally expandable microspheres. The temperature-resistant organosilicon pressure-sensitive adhesive maintained its adhesion and subsequent peelability at high temperatures, while the modified thermally expandable microspheres provided sufficient adhesion at room temperature.

[0063] Plasma treatment: The surfaces of the main heat insulation layer film and the flexible buffer layer film that need to be bonded are subjected to plasma treatment. This step is to ensure that the interfaces of each layer are clean and to prepare for high-quality lamination. The high-energy particles in the plasma bombard the material surface, which can etch away the weak boundary layer and introduce active groups such as hydroxyl and carboxyl groups on its surface, which greatly improves the wettability and reactivity of the surface and enhances the interlayer bonding force, eliminating the need for additional adhesives.

[0064] 2. Preparation of oil-separating film Multilayer lamination and curing: The working layer film prepared above, the main heat insulation layer film treated with plasma, and the flexible buffer layer film are laminated by alignment lamination rollers, first UV irradiated and then heat cured to finally obtain a semi-finished composite film. The purpose of this step is to integrate the three functional layers, so that the three functional layers achieve a firm interface bond and ensure that the functions of each layer are not damaged, so that the performance reaches the optimal state.

[0065] UV irradiation is used before thermosetting because the interfaces of each layer are rich in active free radicals and polar groups after plasma treatment. UV light irradiation can rapidly trigger the cross-linking reaction of the polymer at the interface, forming an extremely thin but strong cross-linked network at the interlayer interface within seconds. This network acts like countless tiny "anchor points," initially but firmly fixing the three functional layers together and preventing relative displacement during subsequent hot pressing. Radiation curing occurs at a very shallow surface layer of the interface, without significantly heating or softening the entire material bulk. The micro-nano structure of the working layer and the porous structure of the insulation layer are well preserved and will not be damaged by heat and pressure. Furthermore, residual air between layers can be left in a limited uncured area. When gradient hot pressing is performed subsequently, this air has a more sufficient path and time to be slowly expelled, reducing the risk of bubbles and delamination.

[0066] Preparation of oil-separating film: The flexible buffer layer of the semi-finished composite film prepared above is lightly pressed and laminated with the smart adhesive layer film at room temperature, then wound up and cured to obtain the oil-separating film. This step combines the smart adhesive layer with the above-prepared functional film body to complete the preparation of the oil-separating film.

[0067] Example 1 A method for preparing an oil-separating film for a stovetop is as follows: Table 1 Main Raw Materials: S1: Raw material preparation and pretreatment.

[0068] S11: Nano-boron nitride and nano-cerium oxide were dispersed in an ethanol-water solution and ultrasonically dispersed to obtain a suspension. Silane coupling agent KH-550 was added to the suspension, mechanically stirred, cooled to room temperature, centrifuged, washed, vacuum dried, and ground to obtain a surface-modified nanocomposite filler. Thermally expandable microspheres were added to an ethanol-water solution and stirred to obtain a suspension. Silane coupling agent KH-901 was added to the suspension, then the temperature was raised to 55℃ and mechanically stirred, centrifuged, washed, and vacuum dried to obtain modified thermally expandable microspheres. The volume ratio of ethanol to water was 4:1; the mass ratio of nano-boron nitride and nano-cerium oxide to the volume ratio of the ethanol-water solution was 1:35; the ultrasonic dispersion parameters were set as follows: power 700W, on 2s / off 1s, duration 45min; the mass of KH-550 was 2.3% of the total weight of the nanofiller; the mechanical stirring parameters were set as follows: 400rpm, temperature 70℃, duration 5h; washing was performed by alternating washing with anhydrous ethanol and deionized water; the vacuum drying parameters were set as follows: vacuum degree -0.085MPa, temperature 80℃, duration 24h.

[0069] S12: Add PEI powder to N-methylpyrrolidone and stir at 65℃ until completely dissolved to obtain a PEI solution; premix the surface-modified nanocomposite filler prepared in S11, antioxidant 1010, dispersant BYK-163 with N-methylpyrrolidone to obtain a premixed slurry; add the premixed slurry to the PEI solution, stir, grind, and degas to obtain the working surface layer slurry. The premixing parameters are set as follows: rotation speed 10000 rpm, time 15 min; degassing parameters are set as follows: vacuum degree -0.095 MPa, time 25 min; based on 100 parts of PEI resin, the component ratios are: N-methylpyrrolidone 400 parts, surface-modified nanocomposite filler 20 parts, antioxidant 1010 1.8 parts, and BYK-163 2 parts.

[0070] S13: Mix silicone resin and solvent N-methylpyrrolidone evenly, add rheology modifier BYK-410, stir at low speed, and add hollow glass microspheres and silica powder until homogeneous. Then, perform vacuum degassing to obtain the main insulation layer slurry. The composition consists of 100 parts silicone resin as the matrix, 200 parts N-methylpyrrolidone as the solvent, 40 parts hollow glass microspheres, 15 parts silica powder, and 1.3 parts BYK-410.

[0071] S14: Mix the two-component liquid silicone rubber with the foaming agent azodicarbonamide and stir until homogeneous to obtain a flexible buffer layer compound. The compound consists of 100 parts of two-component liquid silicone rubber as the base and 3.5 parts of the foaming agent azodicarbonamide.

[0072] S15: Add the modified thermally expandable microspheres to the high-temperature resistant silicone pressure-sensitive adhesive and stir evenly to obtain the smart adhesion layer colloid. The modified thermally expandable microspheres are 10 parts out of 100 parts of the high-temperature resistant silicone pressure-sensitive adhesive.

[0073] S2: Preliminary preparation and curing.

[0074] S21: The working surface layer slurry prepared in S12 is coated onto a PET release film and then dried to obtain a semi-dry working surface layer. The microstructure is imprinted onto the semi-dry working surface layer, and simultaneously irradiated with UV light, followed by heat curing, cooling to room temperature, and then wound up to obtain the working surface layer film. The drying parameters are: temperature 85℃, time 1.5 min; the microstructure is an inverted micropapillary array structure; the UV irradiation parameters are: wavelength 365 nm, intensity 1500 mW / cm². 2 Exposure time: 1 second; thermosetting parameters: temperature 210℃, duration 15 min.

[0075] S22: The main heat insulation layer slurry prepared in S13 is coated onto the polyimide film, then cured by step temperature increase, cooled, and wound up to obtain the main heat insulation layer film. The temperature of the first zone is 90℃ for 8 minutes, the temperature of the second zone is 140℃ for 8 minutes, and the temperature of the third zone is 190℃ for 23 minutes.

[0076] S23: The flexible buffer layer adhesive prepared in S14 is coated onto the PET release film, then cured by stepped heating, cooled, and wound up to obtain the flexible buffer layer film. The stepped heating parameters are set as follows: first zone temperature 90℃, duration 8min; second zone temperature 160℃, duration 4min; third zone temperature 190℃, duration 8min.

[0077] S24: The smart adhesive layer colloid prepared in S15 is coated onto a corona-treated PET release film, followed by low-temperature curing, cooling, winding, and aging to obtain the smart adhesive layer film. The low-temperature curing parameters are set as follows: temperature 70℃, duration 8 min; aging parameters are set as follows: temperature 25℃, duration 24 h.

[0078] S3: Processing and preparation.

[0079] S31: Remove the PET release film from the flexible buffer layer film prepared in S22, and perform plasma treatment on the surfaces that need to be bonded to the main heat insulation layer film prepared in S21. The plasma treatment parameters are set as follows: power 1000W, treatment gas is air, and treatment speed is 3m / min.

[0080] S32: The PET release film is removed from the working layer film prepared in S21, and it is then laminated with the main heat insulation layer film and flexible buffer layer film treated by plasma in S31 using alignment lamination rollers. After lamination, the film is irradiated with UV light to obtain a pre-cured composite film. The pre-cured composite film is then subjected to stepped heating in a hot press, and finally cooled and cured using cooling rollers to obtain a semi-finished composite film. The lamination pressure is set to 1 N / cm. 2 UV irradiation parameter settings: wavelength 395nm, intensity 750mW / cm² 2 Exposure time: 7s; Hot press parameters: Roller gap 1 temperature: 90℃, linear pressure: 15N / cm, residence time: 15s; Roller gap 2 temperature: 130℃, linear pressure: 40N / cm, residence time: 30s; Roller gap 3 temperature: 170℃, linear pressure: 25N / cm, residence time: 15s.

[0081] S33: The flexible buffer layer of the semi-finished composite film prepared in S32 is lightly pressed and laminated with the smart adhesion layer film at room temperature, then wound up and cured to obtain an oil-separating film. Light pressure parameter: 3 N / cm. Figure 2 This is a schematic diagram of Example 1.

[0082] Example 2 The composition and preparation process are the same as in Example 1, except that: In the preparation process, the mass ratio of nano-boron nitride and nano-cerium oxide to the volume ratio of ethanol aqueous solution in S11 is 1:20, the mass of KH-550 is 1.5% of the total weight of nanofillers, and other components are the same.

[0083] In step S11 of the preparation process, the ultrasonic dispersion parameters were set as follows: power 600W, on for 2s / off for 1s, duration 30min. The mechanical stirring parameters were set as follows: 300rpm, temperature 65℃, duration 4h. Other steps were the same.

[0084] In the preparation process, S12 contains 350-450 parts of N-methylpyrrolidone, 15 parts of surface-modified nanocomposite filler, 0.5 parts of antioxidant 1010, 1 part of BYK-163, and other components are the same.

[0085] In the preparation process S13, there are 150 parts of solvent N-methylpyrrolidone, 30 parts of hollow glass microspheres, 10 parts of silica powder, 0.5 parts of BYK-410, and other components are the same.

[0086] In the preparation process S14, the foaming agent azodicarbonamide is 2 parts, and the other components are the same.

[0087] In the preparation process S15, 5 parts of modified thermal expansion microspheres were used, and the other components were the same.

[0088] In the preparation process S21, the drying parameters are: temperature 80℃, duration 1min; the thermosetting parameters are: temperature 200℃, duration 10min, and other steps are the same.

[0089] The stepwise heating parameters in the S22 preparation process are set as follows: first zone temperature 80℃, duration 5min; second zone temperature 130℃, duration 5min; third zone temperature 180℃, duration 15min; other steps are the same.

[0090] The step temperature rise parameters in S23 of the preparation process are set as follows: temperature of the first zone is 80℃ for 5 min, temperature of the second zone is 150℃ for 3 min, temperature of the third zone is 180℃ for 5 min, and other steps are the same.

[0091] The low-temperature curing parameters for process S24 are set as follows: temperature 60℃, duration 5min.

[0092] In step S31 of the preparation process, the plasma processing power is 500W and the processing speed is 1m / min, while the other steps are the same.

[0093] The UV irradiation intensity in the S32 preparation process is 500 mW / cm. 2 Exposure time: 3s; Hot press parameters: Roller gap 1 temperature: 80℃, linear pressure: 10N / cm, residence time: 10s; Roller gap 2 temperature: 120℃, linear pressure: 30N / cm, residence time: 20s; Roller gap 3 temperature: 160℃, linear pressure: 20N / cm, residence time: 10s; Other steps are the same.

[0094] Example 3 The composition and preparation process are the same as in Example 1, except that: In the preparation process, the mass ratio of nano-boron nitride and nano-cerium oxide to the volume ratio of ethanol aqueous solution in S11 is 1:50, the mass of KH-550 is 3.0% of the total weight of nanofillers, and other components are the same.

[0095] In step S11 of the preparation process, the ultrasonic dispersion parameters were set as follows: power 800W, on for 2s / off for 1s, duration 60min. The mechanical stirring parameters were set as follows: 500rpm, temperature 75℃, duration 6h. Other steps were the same.

[0096] The S12 preparation process consists of 450 parts of N-methylpyrrolidone, 25 parts of surface-modified nanocomposite filler, 3 parts of antioxidant 1010, 3 parts of BYK-163, and other components are the same.

[0097] In the preparation process S13, there are 250 parts of solvent N-methylpyrrolidone, 30-50 parts of hollow glass microspheres, 20 parts of silica powder, 2 parts of BYK-410, and other components are the same.

[0098] In the preparation process S14, the foaming agent azodicarbonamide is 5 parts, and the other components are the same.

[0099] In the preparation process S15, 15 parts of modified thermally expandable microspheres were used, and the other components were the same.

[0100] In the preparation process S21, the drying parameters are: temperature 90℃, duration 2min; the thermosetting parameters are: temperature 220℃, duration 20min, and other steps are the same.

[0101] The stepwise heating parameters in the S22 preparation process are set as follows: first zone temperature 100℃, duration 10min; second zone temperature 150℃, duration 10min; third zone temperature 200℃, duration 30min; other steps are the same.

[0102] The step temperature rise parameters in S23 of the preparation process are set as follows: temperature of the first zone is 100℃ for 10 min, temperature of the second zone is 170℃ for 5 min, temperature of the third zone is 200℃ for 10 min, and other steps are the same.

[0103] The low-temperature curing parameters for process S24 are set as follows: temperature 80℃, duration 10min.

[0104] In step S31 of the preparation process, the plasma processing power is 1500W and the processing speed is 5m / min, while the other steps are the same.

[0105] The UV irradiation intensity in the S32 preparation process is 1000 mW / cm. 2 Exposure time: 10s; Hot press parameters: Roller gap 1 temperature: 100℃, linear pressure: 20N / cm, residence time: 20s; Roller gap 2 temperature: 140℃, linear pressure: 50N / cm, residence time: 40s; Roller gap 3 temperature: 180℃, linear pressure: 30N / cm, residence time: 20s; Other steps are the same.

[0106] Example 4 The composition and preparation process are the same as in Example 1, except that: In the preparation process, the mass ratio of nano-boron nitride and nano-cerium oxide to the volume ratio of ethanol aqueous solution in S11 is 1:40, the mass of KH-550 is 1.9% of the total weight of nanofillers, and other components are the same.

[0107] In step S11 of the preparation process, the ultrasonic dispersion parameters were set as follows: power 650W, on for 2s / off for 1s, duration 50min. The mechanical stirring parameters were set as follows: 450rpm, temperature 68℃, duration 5.5h. Other steps were the same.

[0108] In the preparation process, S12 contains 420 parts of N-methylpyrrolidone, 23 parts of surface-modified nanocomposite filler, 2.5 parts of antioxidant 1010, 1.2 parts of BYK-163, and other components are the same.

[0109] In the preparation process S13, there are 170 parts of solvent N-methylpyrrolidone, 35 parts of hollow glass microspheres, 18 parts of silica powder, 0.9 parts of BYK-410, and other components are the same.

[0110] In the preparation process S14, the foaming agent azodicarbonamide is 4 parts, and the other components are the same.

[0111] In the preparation process S15, 13 parts of modified thermal expansion microspheres were used, and the other components were the same.

[0112] In the preparation process S21, the drying parameters are: temperature 88℃, duration 1.8min; the thermosetting parameters are: temperature 215℃, duration 13min, and other steps are the same.

[0113] The stepwise heating parameters in the S22 preparation process are set as follows: first zone temperature 82℃, duration 6min; second zone temperature 133℃, duration 9min; third zone temperature 197℃, duration 25min; other steps are the same.

[0114] The stepwise heating parameters in step S23 of the preparation process are set as follows: temperature of zone 1 is 87℃ for 9 min, temperature of zone 2 is 152℃ for 4.5 min, temperature of zone 3 is 196℃ for 6 min, and other steps are the same.

[0115] The low-temperature curing parameters for process S24 are set as follows: temperature 62℃, duration 9min.

[0116] In step S31 of the preparation process, the plasma processing power is 1300W and the processing speed is 1.5m / min, while the other steps are the same.

[0117] The UV irradiation intensity in the S32 preparation process is 600 mW / cm². 2 Exposure time: 4s; Hot press parameters: Roller gap 1 temperature: 85℃, linear pressure: 12N / cm, residence time: 13s; Roller gap 2 temperature: 122℃, linear pressure: 33N / cm, residence time: 24s; Roller gap 3 temperature: 165℃, linear pressure: 28N / cm, residence time: 18s; Other steps are the same.

[0118] Comparative Example 1 The composition and preparation process are the same as in Example 1, except that: In step S3 of the preparation process, a single-layer structure is used: 100 parts of polyimide film, coated on one side with conventional silicone pressure-sensitive adhesive, and the other steps are the same.

[0119] Comparative Example 2 The composition and preparation process are the same as in Example 1, except that: In step S2 of the preparation process, PTFE is used for coating the working surface, and the other steps are the same.

[0120] Comparative Example 3 The composition and preparation process are the same as in Example 1, except that: In step S2 of the preparation process, the separate preparation of the four types of membranes is removed. The slurry of the working surface layer, the main heat insulation layer, the flexible buffer layer and the smart adhesion layer are applied in sequence and then all processes are completed at once in a high-temperature oven. The temperature is increased in stages: the temperature of the first zone is 90℃ for 8 minutes; the temperature of the second zone is 180℃ for 20 minutes; and the temperature of the third zone is 210℃ for 5 minutes. The other steps are the same.

[0121] Based on Examples 1-4 and Comparative Examples 1-3, samples of the finally prepared oil-separating film were taken, and the initial state and high-temperature yellowing index of the samples after aging were tested. The aging conditions were 168 hours in a 230°C hot air aging chamber, referring to the standard ASTM E313 "Standard Implementation Procedure for Calculating Yellow and White Indices Based on Instrument-Measured Color Coordinates".

[0122] Based on Examples 1-4 and Comparative Examples 1-3, samples of the finally prepared oil-separating film were taken, and the tensile strength and elongation at break of the samples were tested before and after aging, referring to the standard GB / T 1040.3-2022 "Determination of tensile properties of plastics - Part 3: Test conditions for films and sheets".

[0123] Based on Examples 1-4 and Comparative Examples 1-3, samples of the finally prepared oil-separating film were taken and thermal conductivity was tested, referring to the standard ASTM D5470 "Test method for heat transfer properties of thin thermal insulation materials".

[0124] Based on Examples 1-4 and Comparative Examples 1-3, samples of the finally prepared oil-separating film were taken and subjected to a back-side equilibrium temperature test under a 250°C heat source. The sample was covered on a 250°C heating plate, and the surface temperature of the other side of the sample when equilibrium was reached was measured using a thermal imager.

[0125] Based on Examples 1-4 and Comparative Examples 1-3, samples of the finally prepared oil-separating film were taken and subjected to adhesion tests, referring to the standard ASTM D3654 "Pressure-sensitive tape holding power test".

[0126] Based on Examples 1-4 and Comparative Examples 1-3, samples of the finally prepared oil-separating film were taken and subjected to peel strength tests, referring to the standard ASTM D903 "Test method for adhesives' resistance to peeling or detachment".

[0127] The specific test results are shown in Tables 2, 3, and 4. Figure 3 , Figure 4 , Figure 5 As shown: Table 2 Comparison of mechanical properties and anti-yellowing properties after high-temperature aging of Examples 1-4 and Comparative Examples 1-3: Table 3. Comparison of thermal insulation and adhesion performance between Examples 1-4 and Comparative Examples 1-3: Table 4. Process and structural integrity assessment table for Examples 1-4 and Comparative Examples 1-3: The comparison results above show that Example 1 has the best overall performance. Through the selection of high-performance materials, four-layer functional gradient design, KH-550 modification, plasma treatment, and precise process control, the best performance balance was achieved. This indicates that Example 1 successfully solved the problems of the stability and heat insulation performance of the stove oil-separating film material in long-term use at high temperatures. The overall performance of Examples 2 to 4 is slightly lower than that of Example 1, but still maintains a high level. This shows that excellent extraction effect was still achieved under a large range of parameter variations. Although the single polyimide film of Comparative Example 1 is heat-resistant, it has poor heat insulation, high hardness, and poor flexibility, making it unable to adhere to the countertop. The durability and anti-aging properties of conventional silicone pressure-sensitive adhesive under long-term high temperatures are far inferior to the "intelligent adhesion layer" designed in this invention. The flexible buffer layer of Comparative Example 2 is directly pasted to the stove. Its surface is not designed for adhesion, so the initial adhesion and durability are very poor, and it is very easy to soften and fail at high temperatures. Comparative Example 3 combines four layers with different materials, functions, and curing conditions and is formed at high temperature in one go, resulting in extremely poor mechanical properties, heat insulation properties, and adhesion properties.

[0128] In summary, it can be clearly seen from the above embodiments and comparative examples that the oil-separating film for stovetops provided by the present invention is significantly superior to traditional solutions in terms of anti-yellowing performance, heat insulation performance, and adhesion performance. This is attributed to the four-layer gradient thermal management design, which solves the problem that the oil-separating film may cause the polymer material to yellow, become brittle, or lose elasticity in a high-temperature environment.

Claims

1. A stovetop grease barrier, characterized in that: The grease barrier film for the stovetop has a multi-layered composite structure, comprising, from top to bottom: a working surface layer for contact with oil stains, a main heat insulation layer for heat insulation, a flexible buffer layer for stress absorption, and a smart adhesion layer for adhesion to the stovetop; the working surface layer uses polyetherimide as the base resin, with dispersed modified nano-boron nitride and nano-cerium oxide fillers; the main heat insulation layer uses silicone resin as the base, with added hollow glass microspheres and silica powder; the flexible buffer layer uses silicone elastomer containing a foaming agent to form a microporous structure; the smart adhesion layer uses silicone pressure-sensitive adhesive and incorporates modified thermally expandable microspheres; each layer is first molded separately, and then bonded together by low-temperature lamination and curing.

2. The stovetop grease barrier according to claim 1, characterized in that: The working surface layer is prepared by coating a working surface layer slurry onto a PET release film. The composition of the working surface layer slurry is as follows: based on 100 parts of PEI resin, the proportions of other materials are: 350-450 parts of N-methylpyrrolidone, 15-25 parts of surface-modified nanocomposite filler, 0.5-3 parts of antioxidant 1010, and 1-3 parts of BYK-163. The surface-modified nanocomposite filler is composed of modified nano boron nitride and modified nano cerium oxide in a mass ratio of 1:

1.

3. The stovetop grease barrier according to claim 1, characterized in that: The main heat insulation layer is prepared by coating a main heat insulation layer slurry onto a polyimide film. The composition of the main heat insulation layer slurry is as follows: 100 parts of silicone resin as the matrix, and the proportions of other materials are: 150-250 parts of solvent N-methylpyrrolidone, 30-50 parts of hollow glass microspheres, 10-20 parts of silica powder, and 0.5-2 parts of BYK-410.

4. The grease-separating membrane for a stovetop according to claim 1, characterized in that: The flexible buffer layer is prepared by coating a flexible buffer layer adhesive onto a PET release film. The flexible buffer layer adhesive has the following composition: 100 parts of a two-component liquid silicone rubber as the base and 2-5 parts of azodicarbonamide as the foaming agent. The two-component liquid silicone rubber includes component A and component B, which are mixed in a 1:1 mass ratio. Component A includes a base rubber, a platinum catalyst, and a filler, while component B includes a base rubber, a crosslinking agent, an inhibitor, and a filler.

5. The stovetop grease barrier according to claim 1, characterized in that: The smart adhesion layer is prepared by coating the smart adhesion layer colloid onto a corona-treated PET release film; the smart adhesion layer colloid has the following composition: based on 100 parts of high-temperature resistant silicone pressure-sensitive adhesive, 5-15 parts of modified thermal expansion microspheres are prepared.

6. The method for preparing the oil-separating film for the stovetop according to any one of claims 1-5, characterized in that, Includes the following steps: S1: Raw material preparation and pretreatment; S11: Disperse nano-boron nitride and nano-cerium oxide in an aqueous ethanol solution, and then ultrasonically disperse to obtain a suspension; Silane coupling agent KH-550 was added to the suspension, mechanically stirred, cooled to room temperature, centrifuged, washed, vacuum dried, and ground to obtain surface-modified nanocomposite fillers; thermally expanded microspheres were added to an ethanol aqueous solution, stirred, and a suspension was obtained; silane coupling agent KH-901 was added to the suspension, then the temperature was raised to 55℃ and mechanically stirred, centrifuged, washed, and vacuum dried to obtain modified thermally expanded microspheres; S12: Add PEI powder to N-methylpyrrolidone and stir at 65°C until completely dissolved to obtain a PEI solution; premix the surface-modified nanocomposite filler prepared in S11, antioxidant 1010, dispersant BYK-163 with N-methylpyrrolidone to obtain a premixed slurry; add the premixed slurry to the PEI solution, stir, grind, and degas to obtain the working surface layer slurry; S13: Mix the organosilicon resin and solvent N-methylpyrrolidone evenly, add rheology modifier BYK-410, stir and add hollow glass microspheres and silica powder, then perform vacuum degassing to obtain the main insulation layer slurry. S14: Mix the two-component liquid silicone rubber with the foaming agent azodicarbonamide and stir to obtain a flexible buffer layer material; S15: Add the modified thermally expandable microspheres to the high-temperature resistant silicone pressure-sensitive adhesive and stir to obtain the smart adhesion layer colloid; S2: Preliminary preparation and curing; S21: The working surface layer slurry prepared in S12 is coated onto the PET release film and then dried to obtain a semi-dry working surface layer; the microstructure is imprinted onto the semi-dry working surface layer, and then irradiated with UV light, followed by heat curing, cooling to room temperature, and then rolled up to obtain the working surface layer film. S22: The main heat insulation layer slurry prepared in S13 is coated onto the polyimide film, then cured by step heating, cooled, and wound up to obtain the main heat insulation layer film. S23: The flexible buffer layer adhesive prepared in S14 is coated onto the PET release film, then cured by step heating, cooled, and wound up to obtain the flexible buffer layer film. S24: The smart adhesive layer colloid prepared in S15 is coated onto the corona-treated PET release film, and then cured, cooled, wound up, and aged to obtain the smart adhesive layer film. S3: Processing and preparation; S31: Remove the PET release film from the flexible buffer layer film prepared in S22, and perform plasma treatment on the surfaces that need to be bonded to the main heat insulation layer film prepared in S21. S32: Remove the PET release film from the working layer film prepared in S21, and stack it with the main heat insulation layer film and flexible buffer layer film treated by plasma in S31 through the alignment and stacking rollers, and then irradiate it with UV to obtain a pre-cured composite film; the pre-cured composite film is heated in stages through a hot press, and finally cooled and cured by cooling rollers to obtain a semi-finished composite film. S33: The flexible buffer layer of the semi-finished composite film prepared in S32 is lightly pressed and laminated with the smart adhesive layer film at room temperature, then wound up and cured to obtain an oil-separating film.

7. The method for preparing an oil-separating film for a stovetop according to claim 6, characterized in that: The ethanol-water solution described in S11, wherein the volume ratio of ethanol to water is 4:1; The mass ratio of the nano-boron nitride and nano-cerium oxide described in S11 to the volume ratio of the ethanol aqueous solution is 1:20 to 1:

50. The ultrasonic dispersion described in S11 has the following parameter settings: power 600-800W, on 2s / off 1s, duration 30-60min; The KH-550 described in S11 has a mass of 1.5 to 3.0% of the total weight of the nanofillers; The mechanical stirring described in S11 has the following parameters: 300-500 rpm, temperature 65-75℃, and duration 4-6 h. The washing described in S11 involves alternating between anhydrous ethanol and deionized water, washing three times each. The vacuum drying described in S11 has the following parameters: vacuum degree -0.085MPa, temperature 80℃, and duration 24h.

8. The method for preparing an oil-separating film for a stovetop according to claim 6, characterized in that: The premixing described in S12 has the following parameter settings: rotation speed 10000 rpm, duration 15 min; The degassing process described in S12 has the following parameter settings: vacuum degree -0.095MPa, duration 25min.

9. The method for preparing an oil-separating film for a stovetop according to claim 6, characterized in that: The drying described in S21 has the following parameter settings: temperature 80-90℃, duration 1-2 min; The microstructure described in S21 is an antiphase micropapillary array structure. The UV irradiation described in S21 has the following parameter settings: wavelength 365nm, intensity 1500mW / cm². 2 Exposure time: 1 second; The thermosetting parameters described in S21 are: temperature 200-220℃, duration 10-20min; The stepped heating described in S22 has the following parameter settings: first zone temperature 80-100℃, duration 5-10min; second zone temperature 130-150℃, duration 5-10min; third zone temperature 180-200℃, duration 15-30min. The stepped heating described in S23 has the following parameter settings: first zone temperature 80-100℃, duration 5-10min; second zone temperature 150-170℃, duration 3-5min; third zone temperature 180-200℃, duration 5-10min. The curing parameters described in S24 are: temperature 60-80℃, duration 5-10 min, and aging parameters: temperature 25℃, duration 24 h.

10. The method for preparing an oil-separating film for a stovetop according to claim 6, characterized in that: The plasma treatment described in S31 has the following parameter settings: power 500-1500W, treatment gas is air, and treatment speed 1-5m / min; The pressure setting for the lamination described in S32 is 1 N / cm. 2 ; The UV irradiation described in S32 has the following parameters: wavelength 395nm, intensity 500~1000mW / cm². 2 Exposure time: 3-10 seconds; The hot press described in S32 has the following parameter settings: roller gap 1 temperature 80~100℃, linear pressure 10~20N / cm, residence time 10~20s; roller gap 2 temperature 120~140℃, linear pressure 30~50N / cm, residence time 20~40s; roller gap 3 temperature 160~180℃, linear pressure 20~30N / cm, residence time 10~20s.

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