PET-based diamond-like carbon film preservative film and preparation method and equipment of PET-based diamond-like carbon film preservative film

Abstract

The invention relates to the technical field of film processing, in particular to a PET-based diamond-like carbon film preservative film and a preparation method and equipment of the PET-based diamond-like carbon film preservative film. The PET-based diamond-like carbon film preservative film comprises a PET-based film and a diamond-like carbon film, the thickness of the PET base film is 20-50 nanometers, and the diamond-like carbon film covers the surface of the PET base film. The PET-based diamond-like carbon film preservative film and the preparation method and equipment of the PET-based diamond-like carbon film preservative film have remarkable advantages in the aspects of physical performance, chemical stability, production efficiency, operation convenience and the like, the performance of a PET film can be remarkably improved, and the PET-based diamond-like carbon film preservative film and the preparation method and equipment of the PET-based diamond-like carbon film preservative film are suitable for the field of high-end food packaging.

Description

Technical Field

[0001] The invention relates to the technical field of film processing, in particular to a PET-based diamond-like carbon film cling film, and a preparation method and equipment for the PET-based diamond-like carbon film cling film. Background Art

[0002] Traditional PET film is widely used in food packaging due to its good transparency and mechanical properties. However, PET film has limitations in barrier properties, abrasion resistance and protection, which restricts its further development in high-end applications. Summary of the invention

[0003] The purpose of the present invention includes providing a PET-based diamond-like carbon film cling film, a method and equipment for preparing a PET-based diamond-like carbon film cling film, which has significant advantages in physical properties, chemical stability, production efficiency and operational convenience, can significantly improve the performance of PET film, and is suitable for the field of high-end food packaging.

[0004] The embodiments of the present invention can be implemented as follows: In a first aspect, the present invention provides a PET-based diamond-like carbon film cling film, the PET-based diamond-like carbon film cling film comprising a PET base film and a diamond-like carbon film; The thickness of the PET base film is 20-50 nanometers, and the diamond-like carbon film is coated on the surface of the PET base film.

[0005] In an alternative embodiment, the thickness uniformity of the diamond-like carbon film is within ±5%.

[0006] In an optional embodiment, the oxygen permeability deviation of the PET base film is ±20%, and the carbon dioxide permeability deviation is ±20%.

[0007] In an optional embodiment, the moisture permeability deviation of the PET base film is ±20%.

[0008] In a second aspect, the present invention provides a method for preparing a PET-based diamond-like carbon film cling film, which is used to prepare the above-mentioned PET-based diamond-like carbon film cling film, comprising: Transporting the PET base film into the reaction chamber along a preset direction and controlling the temperature of the PET base film entering or in the reaction chamber; Hydrogen and methane are introduced into the reaction chamber as gas sources, and the volume fraction of methane is 0.1% to 5.0%; Start the microwave generator, the microwave power of the microwave generator is 15kW, and the frequency is 2450MHz; Optical emission spectroscopy (OES) was used to detect the relative intensity ratio of C2 groups and atomic hydrogen in the plasma (IC2 / IHa); The diamond-like carbon film SP on the surface of the PET base film was detected by Raman spectrometer. 3 and SP containing graphite 2 spectrum.

[0009] In an optional embodiment, after the microwave generator is started, the microwave power of the microwave generator is adjusted according to the temperature of the PET base film in the reaction chamber and the gas pressure in the reaction chamber to maintain the stability of the plasma.

[0010] In an optional embodiment, after hydrogen and methane are introduced into the reaction chamber as gas sources, the flow ratio of hydrogen and methane is adjusted according to the temperature of the PET base film in the reaction chamber and the gas pressure in the reaction chamber.

[0011] In a third aspect, the present invention provides a PET-based diamond-like carbon film cling film preparation device, which is used to implement the above-mentioned PET-based diamond-like carbon film cling film preparation method, and the PET-based diamond-like carbon film cling film preparation device includes a transmission unit, a reaction chamber, a microwave generator, a gas delivery unit, a pressure control unit, a temperature control unit, an optical emission spectrometer and a Raman spectrometer; The conveying unit is used to convey the PET base film along a preset direction to convey the PET base film to the reaction chamber, and to move the prepared PET-based diamond-like carbon film cling film out of the reaction chamber; The microwave generator is connected to the reaction chamber and is used to generate microwaves in the reaction chamber; The gas delivery unit is used to deliver hydrogen and methane into the reaction chamber; The pressure control unit is used to control the gas pressure in the reaction chamber; The temperature control unit is used to maintain the temperature of the PET base film in the reaction chamber; The optical emission spectrometer is used to detect the relative intensity ratio of C2 groups and atomic hydrogen in the plasma in the reaction chamber; Raman spectrometer is used to detect the diamond-like carbon film SP on the surface of PET base film. 3 and SP containing graphite 2 spectrum.

[0012] The beneficial effects of the PET-based diamond-like carbon film cling film, the preparation method and the device of the PET-based diamond-like carbon film cling film provided by the embodiments of the present invention include: The PET-based diamond-like carbon film cling film comprises a PET base film and a diamond-like carbon film; the PET base film has a thickness of 20-50 nanometers, and the diamond-like carbon film is coated on the surface of the PET base film. The PET-based diamond-like carbon film cling film, the preparation method and equipment of the PET-based diamond-like carbon film cling film have significant advantages in terms of physical properties, chemical stability, production efficiency and operational convenience, can significantly improve the performance of the PET film, and are suitable for the field of high-end food packaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0014] Figure 1 A schematic diagram of the structure of the PET-based diamond-like carbon film cling film provided in this embodiment; Figure 2 A schematic diagram of the structure of the equipment for preparing the PET-based diamond-like carbon film cling film provided in this embodiment.

[0015] Icons: 100-PET-based diamond-like carbon film cling film; 110-PET-based film; 120-diamond-like carbon film; 200-PET-based diamond-like carbon film cling film preparation equipment; 210-transmission unit; 220-reaction chamber; 230-microwave generator; 240-gas delivery unit; 250-pressure control unit; 260-temperature control unit; 270-optical emission spectrometer; 280-Raman spectrometer. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0017] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0019] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear to indicate an orientation or position relationship, they are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0020] In addition, the terms “first”, “second”, etc., if used, are merely used to distinguish between the descriptions and should not be understood as indicating or implying relative importance.

[0021] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention may be combined with each other.

[0022] Please refer to Figure 1 This embodiment provides a PET-based diamond-like carbon film cling film 100, and the PET-based diamond-like carbon film cling film 100 includes a PET base film 110 and a diamond-like carbon film 120; The PET base film 110 has a thickness of 20-50 nanometers, and the diamond-like carbon film 120 covers the surface of the PET base film 110 .

[0023] The principle of the PET-based diamond-like carbon film cling film 100 is: The PET-based diamond-like carbon film cling film 100 comprises a PET base film 110 and a diamond-like carbon film 120; The PET base film 110 has a thickness of 20-50 nanometers, and the diamond-like carbon film 120 is coated on the surface of the PET base film 110 .

[0024] Since the diamond-like carbon film 120 (DLC) has excellent physical and chemical properties, such as high hardness, high wear resistance, high chemical stability, etc., the PET-based diamond-like carbon film cling film 100 can significantly improve the performance of the PET film by coating it on the surface of the PET base film 110, so that it has significant advantages in physical properties, chemical stability, production efficiency and operational convenience, and is suitable for the field of high-end food packaging.

[0025] For further information, please refer to Figure 1In this embodiment, the thickness uniformity of the diamond-like carbon film 120 is within ±5%. The oxygen permeability deviation of the PET base film 110 is ±20%, and the carbon dioxide permeability deviation is ±20%. The moisture permeability deviation of the PET base film 110 is ±20%. The oxygen permeability deviation is set to ±20%, the carbon dioxide permeability deviation is set to ±20%, and the moisture permeability deviation is set to ±20%, because:

[0026] Cling film needs to have a certain gas permeability so that the gas inside the food can be released to prevent food from spoiling. Oxygen permeability, carbon dioxide permeability and moisture permeability are important performance indicators of cling film, which affect the shelf life and quality of food. Control of oxygen permeability and carbon dioxide permeability helps maintain the gas balance in the food packaging, prevent food spoilage due to gas accumulation, and slow down the oxidation process of food. Therefore, different foods have different requirements for oxygen and carbon dioxide permeation during storage. Setting a ±20% deviation range can adapt to the packaging needs of different foods, ensuring that the food remains fresh during storage and transportation to ensure the consistency and reliability of product quality.

[0027] It should be noted that the PET-based diamond-like carbon film cling film 100 can be adjusted according to the needs and packaging requirements of different foods. However, the carbon dioxide permeability is between 100 and 2000 cm³ / (m²·24h·0.1MPa), and its range can also be adjusted according to the needs of specific foods to ensure the freshness of food and prevent spoilage. The moisture permeability deviation is also set to ±20%, the purpose of which is to meet the requirements of foods that need to maintain humidity, such as fruits, vegetables, etc., with lower moisture permeability requirements to slow down the rate of water loss in food.

[0028] Based on the above, please refer to Figure 1 and Figure 2 This embodiment also provides a method for preparing a PET-based diamond-like carbon film cling film 100, which is used to prepare the above-mentioned PET-based diamond-like carbon film cling film 100, comprising: Transferring the PET base film 110 into the reaction chamber 220 along a preset direction, and controlling the temperature of the PET base film 110 entering or located in the reaction chamber 220; Hydrogen and methane are introduced into the reaction chamber 220 as gas sources, and the volume fraction of methane is 0.1% to 5.0%; Start the microwave generator 230, the microwave power of the microwave generator 230 is 15kW, and the frequency is 2450MHz; Optical emission spectroscopy (OES) was used to detect the relative intensity ratio of C2 groups and atomic hydrogen in the plasma (IC2 / IHa); The diamond-like carbon film SP on the surface of the PET base film was detected by Raman spectrometer. 3 and SP containing graphite 2 spectrum.

[0029] It should be noted that, in this embodiment, in addition to microwave coating, other sources such as radio frequency plasma source, vacuum evaporation source, etc. can also be used; and in addition to diamond coating, SiN or SiOx coating can also be used.

[0030] In the above content, the method can be carried out under conditions close to atmospheric pressure, but whether it is strictly carried out under 1 atmosphere needs to be determined according to the actual process parameters and equipment design. The purpose is to avoid the limitation of its processing size by vacuum equipment. Therefore, the use of non-vacuum, i.e. atmospheric pressure film forming technology will change this limitation.

[0031] Furthermore, in the present embodiment, when implementing the above method, a thin film needs to be deposited on the PET base film 110, so during a chemical vapor deposition (CVD) process, the PET base film 110 is placed as a substrate in the reaction chamber 220, and the diamond-like carbon film 120 will be deposited on it. During the CVD process, the substrate is exposed to high temperature and an environment containing specific gases (such as hydrogen and methane), which decompose during the reaction and form a thin film on the surface of the substrate. Therefore, the PET base film 110 can withstand the conditions used in the process, including temperature, pressure and chemical properties.

[0032] It should be noted that in the above content, hydrogen and methane are introduced into the reaction chamber 220 as gas sources because hydrogen and methane are commonly used gas sources in microwave plasma chemical vapor deposition (MPCVD) technology. They are introduced into the reaction chamber 220 and participate in chemical reactions to promote the deposition of the diamond-like carbon film 120 on the PET base film 110. Hydrogen is usually used as a carrier gas and a reducing agent, while methane is used as a carbon source. Under the action of plasma, methane molecules are decomposed to release carbon atoms, which are deposited on the surface of the PET base film 110 to form the diamond-like carbon film 120. Hydrogen helps maintain the stability of the plasma and participates in the chemical reaction to help form a diamond structure.

[0033] Based on the above content, it should be pointed out that after starting the microwave generator 230, the microwave power of the microwave generator 230 is adjusted according to the temperature of the PET base film 110 in the reaction chamber 220 and the gas pressure in the reaction chamber 220 to maintain the stability of the plasma. Specifically, it includes:

[0034] The relationship between power and gas pressure: The radius of the plasma ball increases with the increase of microwave incident power and decreases with the increase of gas pressure. Therefore, if the gas pressure increases, in order to maintain the stability of the plasma, the microwave power needs to be reduced; conversely, if the gas pressure decreases, the microwave power needs to be increased.

[0035] Relationship between power and temperature: Increasing microwave power can generate higher electron density, excite more active hydrogen atoms and carbon-containing groups that are conducive to diamond growth. Therefore, if the temperature of the PET substrate 110 is too low, the microwave power needs to be increased to increase the substrate temperature and promote the growth of diamond; if the substrate temperature is too high, the microwave power needs to be reduced to avoid overheating and affect the quality of the diamond-like carbon film.

[0036] The specific method of power adjustment can be achieved by adjusting the output power of the microwave generator 230. For example, when the microwave power increases from 4000W to 5000W, the quality of the diamond-like carbon film is significantly improved. This shows that by gradually increasing the microwave power, the growth conditions of the diamond-like carbon film can be optimized.

[0037] Power-pressure-temperature coupling method: In MPCVD technology, substrate temperature, power density and deposition pressure have a great influence on the preparation of diamond-like carbon film. The adjustment of a single variable in the preparation process will cause a large change in the sample quality. Therefore, it is necessary to comprehensively consider the coupling effect of these three parameters, and use software combined with specific formulas to couple and adjust the power, deposition pressure and substrate temperature parameters through experimental acquisition parameters.

[0038] Automatic adjustment method: An automatic adjustment method can also be used, by obtaining the standard power sampling value, power sampling value and power change value corresponding to the magnetron under the current power level, filtering multiple power sampling values ​​to determine the final adjustment power sampling value, and then calculating the power level change value to be adjusted based on these values, and adjusting the microwave oven.

[0039] In summary, the adjustment of microwave power needs to be comprehensively considered and finely adjusted according to the changes in substrate temperature and gas pressure, as well as experimental data and software analysis results, in order to maintain the stability of the plasma and optimize the growth conditions of diamond-like carbon films.

[0040] In addition, it should be pointed out that after hydrogen and methane are introduced into the reaction chamber 220 as gas sources, the flow ratio of hydrogen and methane is adjusted according to the temperature of the PET base film 110 in the reaction chamber 220 and the gas pressure in the reaction chamber 220. The flow ratio of hydrogen and methane is adjusted according to the changes in the temperature of the PET base film 110 and the gas pressure in the reaction chamber 220 to maintain the stability of the plasma and optimize the deposition quality of the diamond-like carbon film, specifically, including:

[0041] Coupling effect between substrate temperature and methane concentration: Experimental results show that the coupling effect between substrate temperature and carbon source concentration has a significant impact on the surface morphology, orientation, quality, etc. of diamond-like carbon films. Therefore, when adjusting the flow ratio, the interaction between substrate temperature and methane concentration needs to be considered.

[0042] Effect of gas pressure on the concentration of radicals in plasma: As the gas pressure increases, the relative intensity ratio of C2 radicals and atomic hydrogen in the plasma (IC2 / IHa) increases, and the deposition rate of diamond-like carbon film increases. When the gas pressure is 14 kPa, the deposited diamond-like carbon film has good crystal quality while ensuring the deposition rate. Therefore, when the substrate temperature is high or the gas pressure is low, it is necessary to increase the flow rate of methane to increase the concentration of C2 radicals, thereby improving the deposition rate and quality of diamond-like carbon film.

[0043] Effect of methane volume fraction on the quality of diamond-like carbon film: When the CH4 volume fraction increases, the deposition rate of diamond-like carbon film increases significantly, but after exceeding a certain proportion, the purity of diamond-like carbon film begins to decrease. Therefore, when the substrate temperature is high or the gas pressure is high, the flow rate of methane needs to be appropriately reduced to maintain the purity and quality of the diamond-like carbon film.

[0044] Optimization of flow ratio: Under the condition of constant power and methane volume ratio of 1%, the growth rate of diamond-like carbon film increases with the increase of deposition pressure. When the pressure reaches 14 kPa, the growth rate of diamond-like carbon film slows down if the pressure is further increased. This shows that under the condition of fixed microwave output power, the gas has been fully dissociated in limited energy. By further increasing the pressure in the cavity, the C2 group in the plasma has been saturated and will not grow significantly.

[0045] In summary, the flow ratio of hydrogen and methane needs to be adjusted according to the specific conditions of substrate temperature and gas pressure to maintain the stability of the plasma and optimize the deposition quality of the diamond-like carbon film. The specific adjustment strategy needs to be determined through experiments to determine the optimal flow ratio to achieve the best diamond-like carbon film deposition effect.

[0046] Moreover, based on the above, in the process of preparing the PET-based diamond-like carbon film cling film 100, it is also necessary to control the temperature in the reaction chamber 220 not to exceed 150°C, and after the PET base film 110 is transported to the reaction chamber 220, the temperature of the PET base film 110 entering or located in the reaction chamber 220 does not exceed 150°C. The reason for such a setting is that the temperature resistance range of the PET film is generally between minus 20 degrees and 65 degrees. PET material can be used for a long time within the temperature range of 120°C, and can withstand a high temperature of 150°C for short-term use. The melting point of PET film is usually around 250°C, the long-term use temperature is 120°C, and it can be used for a short time at 150°C. Therefore, the correct operating temperature should be within the temperature resistance range of the PET film, that is, the long-term use temperature does not exceed 120°C, and the short-term use does not exceed 150°C.

[0047] Based on the above, please refer to Figure 1 and Figure 2 The present embodiment further provides a PET-based diamond-like carbon film cling film preparation device 200, which is used to implement the above-mentioned PET-based diamond-like carbon film cling film preparation method 100. The PET-based diamond-like carbon film cling film preparation device 200 includes a transmission unit 210, a reaction chamber 220, a microwave generator 230, a gas delivery unit 240, a pressure control unit 250, a temperature control unit 260, an optical emission spectrometer 270 and a Raman spectrometer 280; The conveying unit 210 is used to convey the PET base film 110 along a preset direction to convey the PET base film 110 to the reaction chamber 220 and to move the prepared PET-based diamond-like carbon film cling film 100 out of the reaction chamber 220; The microwave generator 230 is connected to the reaction chamber 220 and is used to generate microwaves in the reaction chamber 220; The gas delivery unit 240 is used to deliver hydrogen and methane into the reaction chamber 220; The pressure control unit 250 is used to control the gas pressure in the reaction chamber 220; The temperature control unit 260 is used to maintain the temperature of the PET base film 110 in the reaction chamber 220; The optical emission spectrometer 270 is used to detect the relative intensity ratio of C2 groups and atomic hydrogen in the plasma in the reaction chamber 220; The Raman spectrometer 280 is used to detect the diamond-like carbon film 120SP covering the surface of the PET base film 110. 3 and SP containing graphite 2 spectrum.

[0048] It should be noted that the optical emission spectrometer 270 (OES) is used to detect the relative intensity ratio of the C2 group and atomic hydrogen in the plasma in the reaction chamber 220. This detection is crucial for monitoring and optimizing the deposition process of the diamond-like carbon film. The optical emission spectrometer 270 can provide detailed information about the chemically active groups in the plasma, including their concentration and excitation state, by analyzing the emission spectrum of specific groups in the plasma. This information helps to understand the degree of dissociation of methane and the chemical reaction mechanism during diamond growth. By monitoring the relative intensity ratio of the C2 group and atomic hydrogen (IC2 / IHa), the deposition quality of the diamond-like carbon film can be evaluated because this ratio is closely related to the purity and crystal quality of the diamond-like carbon film.

[0049] It can be seen from the above that the thickness uniformity of the diamond-like carbon film 120 is within ±5%. Based on this, the present embodiment uses a Raman spectrometer for detection, that is, the surface morphology, uniformity and quality of the diamond-like carbon film are characterized by the Raman spectrometer. The changes in the Raman spectrum and its half-maximum width can indicate that the crystallinity, quality and uniformity of the diamond-like carbon film are improved. In order to control its uniformity within ±5%, the following contents are also included: Optimization of gas flow mode: By changing the gas flow mode, the crystallinity, quality and uniformity of diamond-like carbon film can be improved. For example, by adding a gas outlet to change the gas outlet mode, the number of gas molecules increases, the strength of H atoms and CH active groups in the plasma is enhanced, and the number of atomic H and carbon-containing active groups diffused to the substrate surface increases, thereby improving the growth rate and uniformity of diamond-like carbon film; and by providing a more suitable environment through an improved gas flow pattern, the distribution of reaction gas on the substrate surface is improved, thereby improving the uniformity of high-quality diamond-like carbon film deposition. Using an infrared thermometer to monitor the substrate temperature in real time through the observation window, and controlling the flow of CH4 and CO2 through a mass flow meter, the deposition conditions can be adjusted in real time to ensure the uniformity of the diamond-like carbon film.

[0050] Through the comprehensive application of the above methods, the thickness uniformity of the diamond-like carbon film 120 can be effectively controlled to within ±5%. These methods involve optimization of the deposition process, real-time monitoring, advanced deposition technology, and improvement of equipment design, which work together to achieve high-quality diamond-like carbon film 120 deposition.

[0051] Based on the above-mentioned PET-based diamond-like carbon film cling film 100 preparation method and equipment, its working process is as follows: Prepare the PET base film 110: select a suitable PET base film 110 with a thickness between 20-50 nanometers; Gas transportation: hydrogen and methane are introduced, with the volume fraction of methane ranging from 0.1% to 5.0% as carbon source and reducing agent; Microwave plasma excitation: The diamond-like carbon film 120 is deposited on the PET base film 110 at atmospheric pressure by microwave plasma chemical vapor deposition (MPCVD) technology, with a microwave power of 15 kW and a frequency of 2450 MHz; Parameter control: Control the gas pressure within the range of 1.3×10^3 to 10.7×10^3 Pa, and maintain the substrate temperature within the range of 500 to 900°C; Film quality detection: Optical emission spectroscopy (OES) is used to detect the relative intensity ratio (IC2 / IHa) of C2 groups and atomic hydrogen in the plasma, and Raman spectrometer 280 is used to detect the diamond-like carbon film 120SP covered on the surface of the PET base film 110. 3 and SP containing graphite 2 Spectrum of Here’s how it works: Microwave plasma excitation: Microwaves excite glow discharge in the reaction area to generate high-density plasma. Electrodeless discharge avoids the problem of electrode contamination during material deposition, making the equipment run stably and the deposited film quality high; The role of hydrogen and methane: hydrogen decomposes at high temperature to form a large number of free hydrogen radicals, while methane, as a carbon source, decomposes under the action of plasma to release carbon atoms, which are deposited on the surface of the PET film to form a diamond-like carbon film 120; Film growth control: The deposition growth of diamond-like carbon film is controlled by kinetics, and a small amount of carbon source and excess hydrogen are used to achieve the preparation of polycrystalline diamond-like carbon film.

[0052] Specifically, the function of the conveying unit 210 is to convey the PET base film 110 along a preset direction to convey the PET base film 110 to the reaction chamber 220, and to move the prepared PET-based diamond-like carbon film cling film 100 out of the reaction chamber 220, thereby completing the input and output of materials, and controlling the conveying speed according to relevant detection data; The function of the microwave generator 230 is to generate microwave signals. It converts direct current power into microwave energy through internal circuits and components to output high-power microwave signals. In the chemical vapor deposition (CVD) process, the microwaves generated by the microwave generator 230 are transmitted to the reactor by waveguides, and a mixed gas composed of different gases is introduced. The high-intensity microwaves can excite and decompose the carbon-containing gas above the substrate to form active carbon-containing groups and atomic hydrogen, and form plasma, thereby depositing a diamond-like carbon film on the substrate; and the microwaves generated by the microwave generator 230 can control the characteristics of the plasma, such as density and temperature, which is crucial to the quality and characteristics of the film during the deposition process; and the microwave generator 230 can provide stable continuous wave microwave power, which is very important for maintaining stability and repeatability in the CVD process; in addition, the microwave generator 230 usually includes parts such as oscillators, amplifiers and modulators, which work together to generate stable microwave signals and can adjust parameters such as the amplitude, frequency and phase of the signal. Therefore, the microwave generator 230 plays a core role in the MPCVD process, generating microwaves to excite the reaction gas to form plasma, thereby promoting the deposition of the diamond-like carbon film 120 on the PET base film 110. The performance of the microwave generator 230 directly affects the growth rate, quality and uniformity of the film.

[0053] The function of the gas delivery unit 240 is to introduce hydrogen and methane into the reaction chamber 220, and to accurately control the volume fraction of methane between 0.1% and 5.0%. This helps to maintain the stability of the plasma and optimize the deposition process of the diamond-like carbon film 120; maintain a specific oxygen content and pressure in the reaction chamber 220, these parameters have a significant effect on the growth of the diamond-like carbon film, for example, the introduction of an appropriate amount of oxygen can reduce the impurities of the diamond-like carbon film and promote its growth; provide the necessary reaction gas, methane as a carbon source is the main raw material for diamond growth, and hydrogen is used as a carrier gas and reducing agent to help the carbon atoms in methane form a diamond structure on the PET base film 110; in addition, the introduction of different auxiliary gases, such as oxygen, carbon dioxide, etc., has a significant effect on the morphology, quality and growth rate of the diamond-like carbon film, for example, the addition of carbon dioxide can improve the film quality and promote its growth.

[0054] The function of the pressure control unit 250 is to monitor and automatically adjust the pressure in the reaction chamber 220 to ensure that a constant pressure environment is maintained during the deposition of the diamond-like carbon film 120; it can collect the pressure value through the pressure transmitter, and after comparing it with the preset value, adjust the actuator (such as a regulating valve) through the controller to stabilize the pressure value within the set range, which is crucial for maintaining the stability of the plasma and optimizing the deposition process of the diamond-like carbon film; The function of the temperature control unit 260 is: the temperature control system is used to maintain the temperature of the PET base film 110 in the reaction chamber 220 within a preset safe and effective range (not exceeding 150°C); the structure of the temperature control unit 260 can be composed of sensors, controllers and actuators, and through temperature feedback control, the difference between the actual temperature and the set value is continuously measured and adjusted to maintain temperature stability, which is critical for controlling the growth rate and quality of the film.

[0055] The function of the optical emission spectrometer 270 is as follows: The optical emission spectrometer 270 is used to detect the relative intensity ratio (IC2 / IHa) of the C2 group and atomic hydrogen in the plasma in the reaction chamber 220. The instrument can analyze the characteristic spectral lines of the elements in the plasma to determine the type and content of the elements in the sample. In this process, OES helps monitor and optimize the deposition conditions of the diamond-like carbon film 120 to ensure the quality and uniformity of the film.

[0056] The function of the Raman spectrometer 280 is as follows: The Raman spectrometer 280 is used to detect the diamond-like carbon film 120SP on the surface of the PET base film 110. 3 and SP containing graphite 2 It measures the frequency change of Raman scattered light to obtain the molecular vibration information of the sample, thereby determining and confirming the composition of the sample. This technology is crucial to ensure the high quality and high performance of diamond-like carbon film 120.

[0057] In summary, the PET-based diamond-like carbon film cling film 100, the method and equipment for preparing the PET-based diamond-like carbon film cling film 100 have the following advantages: Coating under atmospheric pressure does not require vacuum equipment, which will greatly save coating costs. Coating under atmospheric pressure can process any large object without being restricted by the vacuum chamber. Diamond-like carbon film (DLC) film has anti-oxygen, water, and ultraviolet properties. It is a high oxygen blocking film and a high water vapor blocking film. The microwave plasma processing area is large, it is a non-polar power source, and there is no pollution source. Excellent physical and chemical properties: Diamond-like carbon film 120 (DLC) has extremely high hardness, low friction coefficient, high elastic modulus, high thermal conductivity, good chemical stability and large bandgap width, which make PET-based diamond-like carbon film cling film 100 have better protection performance and durability; High purity and crystal quality: Raman spectrometer 280 can detect the diamond-like carbon film 120SP on the surface of the PET base film 110. 3 and SP containing graphite 2 The spectrum ensures that the prepared diamond-like carbon film 120 has high purity and good crystallinity; Thickness uniformity control: By precisely controlling deposition parameters, the thickness uniformity of the diamond-like carbon film 120 can be controlled within ±5%, ensuring product consistency and reliability; Precise control of air permeability: By adjusting the preparation parameters, the oxygen permeability and carbon dioxide permeability of the PET base film 110 can be precisely controlled within ±20%, and the moisture permeability can be precisely controlled within ±20%, thus meeting the preservation requirements of different foods; High-efficiency deposition rate and quality: Microwave plasma chemical vapor deposition (MPCVD) technology can achieve high-efficiency diamond-like carbon film 120 deposition, improve production efficiency and reduce costs; No internal electrode pollution: MPCVD method has no internal electrodes, which avoids electrode discharge pollution and electrode corrosion, and improves the purity and quality of the film; Wide operating pressure range: MPCVD technology can operate in a wide range of pressures, providing greater operational flexibility; High plasma density: MPCVD technology can generate large-volume uniform plasma, which is conducive to the deposition of diamond-like carbon films on curved or complex surfaces; Non-contact, non-destructive technology: Raman spectroscopy and optical emission spectroscopy (OES) are both non-contact, non-destructive technologies that can be analyzed without damaging the sample and are suitable for in-situ analysis; Fast and easy to operate: OES technology is fast and easy to operate. It can measure a variety of elements over a wide range, including important elements such as carbon, sulfur, phosphorus, boron, nitrogen, etc., with high accuracy; Suitable for a variety of analyses: Raman spectroscopy is suitable for in situ, in vitro and in vivo analysis, and its tolerance to water allows it to be used in a variety of environments; In summary, the PET-based diamond-like carbon film cling film preparation equipment 200 based on the above content and the PET-based diamond-like carbon film cling film 100 prepared by the preparation method of the PET-based diamond-like carbon film cling film 100 have significant advantages in physical properties, chemical stability, production efficiency, and operational convenience, and are suitable for the field of high-end food packaging.

[0058] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A PET-based diamond-like carbon film cling film, characterized in that: The PET-based diamond-like carbon film cling film comprises a PET base film and a diamond-like carbon film; The thickness of the PET base film is 20-50 nanometers, and the diamond-like carbon film is coated on the surface of the PET base film.

2. The PET-based diamond-like carbon film cling film according to claim 1, characterized in that: The thickness uniformity of the diamond-like carbon film is within ±5%.

3. The PET-based diamond-like carbon film cling film according to claim 1, characterized in that: The oxygen permeability deviation of the PET base film is ±20%, and the carbon dioxide permeability deviation is ±20%.

4. The PET-based diamond-like carbon film cling film according to claim 1, characterized in that: The moisture permeability deviation of the PET base film is ±20%.

5. A method for preparing a PET-based diamond-like carbon film cling film, used for preparing the PET-based diamond-like carbon film cling film as claimed in any one of claims 1 to 4, characterized in that: include: Transporting the PET base film into a reaction chamber along a preset direction, and controlling the temperature of the PET base film entering or in the reaction chamber; Introducing hydrogen and methane as gas sources into the reaction chamber, wherein the volume fraction of methane is 0.1% to 5.0%; Start a microwave generator with a microwave power of 15 kW and a frequency of 2450 MHz; Optical emission spectroscopy (OES) was used to detect the relative intensity ratio of C2 groups and atomic hydrogen in the plasma (IC2 / IHa); The diamond-like carbon film SP on the surface of the PET base film was detected by Raman spectrometer. 3 and SP containing graphite 2 spectrum.

6. The method for preparing the PET-based diamond-like carbon film cling film according to claim 5, characterized in that: After the microwave generator is started, the microwave power of the microwave generator is adjusted according to the temperature of the PET base film in the reaction chamber and the gas pressure in the reaction chamber to maintain the stability of the plasma.

7. The method for preparing the PET-based diamond-like carbon film cling film according to claim 5, characterized in that: After hydrogen and methane are introduced into the reaction chamber as gas sources, the flow ratio of hydrogen and methane is adjusted according to the temperature of the PET base film in the reaction chamber and the gas pressure in the reaction chamber.

8. A preparation device for a PET-based diamond-like carbon film cling film, used for implementing the preparation method for a PET-based diamond-like carbon film cling film as claimed in any one of claims 5 to 7, characterized in that: The preparation equipment of the PET-based diamond-like carbon film cling film comprises a transmission unit, a reaction chamber, a microwave generator, a gas delivery unit, a pressure control unit, a temperature control unit, an optical emission spectrometer and a Raman spectrometer; The conveying unit is used to convey the PET base film along a preset direction to convey the PET base film to the reaction chamber, and to move the prepared PET-based diamond-like carbon film cling film out of the reaction chamber; The microwave generator is connected to the reaction chamber and is used to generate microwaves in the reaction chamber; The gas delivery unit is used to deliver hydrogen and methane into the reaction chamber; The pressure control unit is used to control the gas pressure in the reaction chamber; The temperature control unit is used to maintain the temperature of the PET base film in the reaction chamber; The optical emission spectrometer is used to detect the relative intensity ratio of C2 groups and atomic hydrogen in the plasma in the reaction chamber; The Raman spectrometer is used to detect the diamond-like carbon film SP on the surface of the PET base film. 3 and SP containing graphite 2 spectrum.

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