Method for producing black film and black film

Abstract

The application provides a preparation method of black film and the black film. The preparation method of the black film comprises the following steps: fully contacting carbon black particles after pretreatment with polyethylene glycol water mist to generate carbon black particles coated by polyethylene glycol; freeze-drying the carbon black particles coated by polyethylene glycol; adding the freeze-dried carbon black particles into a mixed solution formed by dissolving polyethylene glycol diacrylate, polyacrylate and methoxy polyethylene glycol acrylate in deionized water; adding a polyether defoaming agent without silicon into the mixed solution to form a raw solution; grinding the raw solution and covering the raw solution on the surface of a bearing film; and performing drying and ultraviolet irradiation to form the black film. The black film can be directly contacted with a plate, and the preparation method of the black film dissolved in water is simple, and the black film can be removed without organic solvents.

Description

Technical Field

[0001] This invention relates to the field of printing and copying technology, and more specifically, to a method for preparing a black film and the black film itself. Background Technology

[0002] Currently, the resin layer of photosensitive resin plates is easily affected by external conditions such as light and dust in the environment before plate making, causing defects and making it impossible to accurately reproduce text and patterns. Therefore, a black film is coated on the resin layer of the photosensitive resin plate for protection. During the plate making process, according to the text and pattern to be expressed, the black film is removed by laser ablation to expose the resin layer (the resin material used is soluble in water without photocuring, but insoluble in water after photocuring and cross-linking polymerization). The entire plate is then exposed to ultraviolet light, and the photosensitive resin without the black film is cured. The exposed plate is then washed with water to dissolve the remaining black film and uncured resin, forming a raised pattern. After auxiliary processing, a printable plate is obtained. However, the existing black film preparation methods have the following problems: organic solvents are required in the preparation of black film raw materials, or the prepared black film is not soluble in water and requires the use of organic solvents for dissolution and removal, or the film-forming properties are poor, or it cannot directly contact the plate.

[0003] Therefore, how to prepare a black film that can directly contact the substrate, is simple to prepare by dissolving in water, and does not require organic solvents has become an urgent problem to be solved. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0005] Therefore, a first aspect of the present invention provides a method for preparing a black film.

[0006] A second aspect of the present invention provides a black film.

[0007] In view of this, the first aspect of the present invention provides a method for preparing a black film, comprising: preparing a polyethylene glycol aqueous solution using polyethylene glycol and deionized water; atomizing the polyethylene glycol aqueous solution to form a polyethylene glycol water mist; allowing pretreated carbon black particles to fully contact the polyethylene glycol water mist to generate polyethylene glycol-coated carbon black particles; freeze-drying the polyethylene glycol-coated carbon black particles; dissolving polyethylene glycol diacrylate, polyacrylate, and methoxy polyethylene glycol acrylate in deionized water under yellow light to form a mixture; adding the freeze-dried carbon black particles to the mixture and stirring; adding a silicone-free polyether defoamer to the mixture and stirring to generate a stock solution; grinding the stock solution; covering the surface of a carrier film with the ground stock solution to form a coating; drying the coated carrier film; irradiating the dried coated carrier film with ultraviolet light; and detaching the coating from the carrier film after ultraviolet irradiation to obtain the prepared black film.

[0008] The method for preparing the black film provided by this invention includes: preparing a polyethylene glycol aqueous solution using polyethylene glycol and deionized water; atomizing the polyethylene glycol aqueous solution to form a polyethylene glycol water mist; ensuring sufficient contact between pretreated carbon black particles and the polyethylene glycol water mist to generate polyethylene glycol-coated carbon black particles; freeze-drying the polyethylene glycol-coated carbon black particles; dissolving polyethylene glycol diacrylate, polyacrylate, and methoxy polyethylene glycol acrylate in deionized water under yellow light to form a mixture; adding the freeze-dried carbon black particles to the mixture and stirring thoroughly; adding a silicone-free polyether defoamer to the mixture and stirring to generate a stock solution; grinding the stock solution; coating the surface of a carrier film with the ground stock solution; drying the carrier film with the coating; irradiating the dried carrier film with the coating with ultraviolet light; and detaching the coating from the carrier film after ultraviolet irradiation to obtain the prepared black film. The black film manufactured using the method described in this application is produced by placing polyethylene glycol-coated carbon black particles in a mixture of polyethylene glycol diacrylate, polyacrylate, and methoxy polyethylene glycol acrylate dissolved in deionized water, followed by stirring and grinding. This ensures that the carbon black is evenly distributed throughout the slurry, guaranteeing the uniformity of the slurry's blackness. Furthermore, polyethylene glycol, polyethylene glycol diacrylate, polyacrylate, and methoxy polyethylene glycol acrylate are all water-soluble materials; therefore, the formed black film can be directly removed by washing with water after curing, effectively preventing the corrosion of the photosensitive water-soluble resin by organic reagents and improving the ease of black film removal. Since ultraviolet light is essentially eliminated in a yellow light environment, and ultraviolet light can cause organic reagents to cure, the use of a yellow light environment effectively avoids the curing of organic reagents. Adding a silicone-free polyether defoamer to the mixture prevents air bubbles from forming in the film layer during coating, thus preventing quality issues. The stock solution is applied to the surface of a carrier membrane to form a coating. The coated carrier membrane is then dried and irradiated with ultraviolet light. This causes the water in the stock solution to evaporate, while the organic matter and carbon black particles in the stock solution solidify, forming a black film on the carrier membrane. The combination of heating and ultraviolet light accelerates the film formation process.

[0009] The method for preparing the black film described in this application is simple, allowing the black film to directly contact the printing plate. It only requires mixing organic reagents in a fixed ratio and finely grinding the carbon black particles. Furthermore, the organic reagents used all possess good water solubility, and water is used as the solvent throughout the entire process. Even after the black film has cured, it retains good water solubility and can be removed by washing it with water along with the unexposed water-soluble resin during subsequent cleaning.

[0010] The method for preparing the black film according to the present invention may also have the following additional technical features:

[0011] In some possible designs, polyacrylates include: polymethyl acrylate, polyethyl acrylate, and polypropyl acrylate. Polyacrylates with a carbon atomic weight of no more than 3 atoms have good solubility, reducing the incompatibility between materials.

[0012] In some possible designs, the mass ratio of polyethylene glycol diacrylate to methoxy polyethylene glycol acrylate is greater than or equal to 200:3 and less than or equal to 200:1; the mass ratio of polyethylene glycol diacrylate to polyacrylate is greater than or equal to 5:2 and less than or equal to 5:1; the relative molecular mass of polyethylene glycol diacrylate is greater than or equal to 4000 and less than or equal to 10000; the relative molecular mass of polyacrylate is greater than or equal to 500 and less than or equal to 2000; and the relative molecular mass of methoxy polyethylene glycol acrylate is greater than or equal to 300 and less than or equal to 3000.

[0013] In this design, polyethylene glycol diacrylate (PEG) is water-soluble and remains soluble after photopolymerization, acting as a film-forming and adhesive agent with high strength. Polyacrylate, while having lower strength, possesses good adhesion and elasticity, assisting in film formation and improving film quality. Methoxylated PEG is water-soluble and used for UV-initiated polymerization. The entire material system is based on acrylates, simplifying the system and reducing material incompatibility. Since PEG is the main film-forming component, its appropriate molecular weight determines the smoothness of the formed black film. Polyacrylate acts as an adhesive aiding film formation, requiring a suitable proportion and lower molecular weight to ensure reinforcement of adhesion and elasticity. Methoxylated PEG's role is to initiate polymerization; therefore, a suitable proportion and molecular weight are needed to ensure its complete effect throughout the film, resulting in a good forming effect. The proportion of polyacrylate is adjusted based on the viscosity of the black film, while the proportion of methoxylated PEG is adjusted according to the UV polymerization process. Specifically, take 100g of polyethylene glycol diacrylate 5000, 20g of polymethyl acrylate 1000 and 1.5g of methoxy polyethylene glycol acrylate 2000, stir and dissolve in 500ml of deionized water to form a mixture.

[0014] In some possible designs, the relative molecular mass of polyethylene glycol is greater than or equal to 1000 and less than or equal to 3000, and the concentration of polyethylene glycol aqueous solution is greater than or equal to 40% and less than or equal to 60%.

[0015] In this design, the relative molecular mass of polyethylene glycol (PEG) is between 1000 and 3000, and the concentration of the PEG aqueous solution is between 40% and 60%. The molecular mass of PEG directly determines its molecular size. An excessively large relative molecular mass prevents PEG from completely coating the carbon black particles, while an excessively small relative molecular mass may result in PEG failing to coat the carbon black particles or forming a thin coating film that is not effective. Setting the PEG aqueous solution concentration between 40% and 60% ensures that PEG is evenly distributed in the water mist during subsequent mist formation, thus guaranteeing effective coating of the carbon black particles. Specifically, the relative molecular mass of PEG is chosen to be 1500, and the concentration of the PEG aqueous solution is 50%.

[0016] In some possible designs, when methoxy polyethylene glycol acrylate is dissolved in deionized water, the temperature of the deionized water is greater than or equal to 20°C and less than or equal to 40°C.

[0017] In this design, methoxylated polyethylene glycol acrylate is used to initiate polymerization, therefore, the appropriate temperature determines the polymerization effect. Temperatures that are too high or too low will result in poor polymerization and difficulty in forming the black film. Dissolving the methoxylated polyethylene glycol acrylate in deionized water at a temperature of 20°C to 40°C ensures optimal polymerization and results in more uniform black film imaging.

[0018] In some possible designs, the pretreated carbon black particles have a particle size greater than or equal to 30 nm and less than or equal to 100 nm, and the ground carbon black particles have a particle size greater than or equal to 30 nm and less than or equal to 70 nm.

[0019] In this design, the carbon black particles require fine grinding pretreatment to ensure uniform distribution throughout the raw slurry and the formed black film, thereby guaranteeing the uniformity and light-blocking properties of the black film. Specifically, the pretreated carbon black particles have a particle size of 60 nm, and the ground carbon black particles also have a particle size of 60 nm.

[0020] In some possible designs, the original solution is coated on the surface of the carrier film to form a coating with a thickness greater than or equal to 2 μm and less than or equal to 8 μm.

[0021] In this design, the thickness of the coating determines the thickness of the black film. The black film needs good light-blocking properties, so the coating thickness needs to be set between 2μm and 8μm. Too thick a coating would be wasteful, while too thin a coating would not provide a good light-blocking effect. Specifically, the coating thickness is 3μm.

[0022] In some possible designs, the carrier membrane includes a PEEK membrane, and more specifically, the carrier membrane is a PEEK membrane.

[0023] In this design, the carrier membrane is a PEEK membrane. PEEK membranes have excellent properties such as high temperature resistance and self-lubrication, and the prepared black film has low shrinkage after peeling.

[0024] In some possible designs, when drying the coated carrier film, the drying temperature is greater than or equal to 70°C and less than or equal to 90°C, and the drying time is greater than or equal to 0.5 hours and less than or equal to 1.5 hours.

[0025] In this design, by limiting the drying temperature and duration, the black film can be effectively dehydrated while ensuring that it does not shrink excessively, which would affect its compatibility. Specifically, the drying temperature is 80℃ for 1 hour.

[0026] In some possible designs, the shrinkage before and after the black film detaches is greater than or equal to 0.5% and less than or equal to 1%.

[0027] In this design, the shrinkage before and after the black film detaches is between 0.5% and 1%. This ensures that the black film and the coating are essentially the same size, thus eliminating the need to calculate the coating size during the black film's fabrication. This reduces production costs.

[0028] In some possible designs, the mass ratio of silicone-free polyether defoamer to polyethylene glycol diacrylate is greater than or equal to 1 / 200 and less than or equal to 1 / 300; silicone-free polyether defoamers include: fatty alcohol defoamers.

[0029] In this design, the silicone-free polyether defoamer includes a fatty alcohol defoamer. During the process of coating the raw slurry onto the carrier membrane, air bubbles may form in the membrane layer, affecting quality. Adding a fatty alcohol defoamer can prevent air bubbles from forming in the membrane layer, thereby improving the uniformity of the black film.

[0030] In some possible designs, when the dried coated carrier film is irradiated with ultraviolet light, the irradiation time is greater than or equal to 3 minutes and less than or equal to 15 minutes.

[0031] In this design, by limiting the ultraviolet irradiation time to at least 3 minutes, the molding effect of the black film is ensured, allowing the structure within the black film to be fixed. Conversely, limiting it to at least 15 minutes prevents excessive shrinkage of the black film, thus guaranteeing its compatibility.

[0032] The second aspect of the present invention provides a black film, which is made by the preparation method of the black film provided by any of the technical solutions of the first aspect of this application. Therefore, the black film provided by the present invention has all the beneficial effects of the preparation method of the black film provided by any of the technical solutions of the first aspect of the present invention, which will not be repeated here.

[0033] The black film provided by this invention has a black-white density value D greater than or equal to 0 and less than or equal to 0.06. The black-white density of the black film determines the light-blocking rate. In this application, the black-white density value D of the black film is between 0 and 0.06, ensuring that the generated black film has a good light-blocking effect.

[0034] Additional aspects and advantages of the invention will become apparent in the following description or may be learned by practice of the invention. Attached Figure Description

[0035] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0036] Figure 1 A schematic diagram of a method for preparing a black film according to an embodiment of the present invention is shown;

[0037] Figure 2 A schematic diagram of a method for preparing a black film according to another embodiment of the present invention is shown. Detailed Implementation

[0038] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0039] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0040] The following reference Figure 1 A method for preparing a black film according to some embodiments of the present invention is described.

[0041] Example 1

[0042] According to one embodiment of the present invention, a method for preparing a black film is provided, comprising:

[0043] like Figure 1 As shown, the method for preparing the black film provided by the present invention includes:

[0044] S101: Prepare an aqueous solution of polyethylene glycol using polyethylene glycol and deionized water.

[0045] S102: Atomizes the polyethylene glycol aqueous solution to form a polyethylene glycol water mist.

[0046] S103: Contact the pretreated carbon black particles with polyethylene glycol water mist to generate carbon black particles coated with polyethylene glycol.

[0047] S104: Freeze-dried carbon black particles coated with polyethylene glycol.

[0048] S105: Under yellow light, polyethylene glycol diacrylate, polyacrylate and methoxy polyethylene glycol acrylate are dissolved in deionized water to form a mixture.

[0049] S106: Add freeze-dried carbon black granules to the mixture and stir.

[0050] S107: Add a silicone-free polyether defoamer to the mixture and stir to generate the stock solution.

[0051] S108: Grinding treatment of the original solution.

[0052] S109: The raw liquid after grinding is applied to the surface of the carrier film to form a coating.

[0053] S110: The coated carrier film is dried, and the dried coated carrier film is irradiated with ultraviolet light. After ultraviolet light irradiation, the coating is separated from the carrier film to obtain the prepared black film.

[0054] The black film manufactured using the method described in this application is produced by placing polyethylene glycol-coated carbon black particles in a mixture of polyethylene glycol diacrylate, polyacrylate, and methoxy polyethylene glycol acrylate dissolved in deionized water, followed by stirring and grinding. This ensures that the carbon black is evenly distributed throughout the slurry, guaranteeing the uniformity of the slurry's blackness. Furthermore, polyethylene glycol, polyethylene glycol diacrylate, polyacrylate, and methoxy polyethylene glycol acrylate are all water-soluble materials; therefore, the formed black film can be directly removed by washing with water after curing, effectively preventing the corrosion of the photosensitive water-soluble resin by organic reagents and improving the ease of black film removal. Since ultraviolet light is essentially eliminated in a yellow light environment, and ultraviolet light can cause organic reagents to cure, the use of a yellow light environment effectively avoids the curing of organic reagents. Adding a silicone-free polyether defoamer to the mixture prevents air bubbles from forming in the film layer during coating, thus preventing quality issues. The stock solution is applied to the surface of a carrier membrane to form a coating. The coated carrier membrane is then dried and irradiated with ultraviolet light. This causes the water in the stock solution to evaporate, while the organic matter and carbon black particles in the stock solution solidify, forming a black film on the carrier membrane. The combination of heating and ultraviolet light accelerates the film formation process.

[0055] Example 2

[0056] This invention proposes a method for preparing a black film, such as... Figure 2 As shown, it includes:

[0057] S201: A polyethylene glycol aqueous solution is prepared by mixing polyethylene glycol and deionized water, wherein the relative molecular mass of polyethylene glycol is between 1000 and 3000, and the concentration of the polyethylene glycol aqueous solution is between 40% and 60%.

[0058] S202: Atomizes the polyethylene glycol aqueous solution to form a polyethylene glycol water mist;

[0059] S203: Ensures that the pretreated carbon black particles come into full contact with the polyethylene glycol water mist to generate carbon black particles coated with polyethylene glycol.

[0060] S204: Freeze-dried carbon black particles coated with polyethylene glycol;

[0061] S205: Under yellow light, polyethylene glycol diacrylate, polyacrylate, and methoxy polyethylene glycol acrylate are dissolved in deionized water to form a mixture, wherein the mass ratio of polyethylene glycol diacrylate to methoxy polyethylene glycol acrylate is between 200:3 and 200:1, the mass ratio of polyethylene glycol diacrylate to polyacrylate is between 5:2 and 5:1, the relative molecular mass of polyethylene glycol diacrylate is between 4000 and 10000, the relative molecular mass of polyacrylate is between 500 and 2000, and the relative molecular mass of methoxy polyethylene glycol acrylate is between 300 and 3000.

[0062] S206: Add freeze-dried carbon black granules to the mixture and stir thoroughly;

[0063] S207: Add a silicone-free polyether defoamer to the mixture and stir to generate the stock solution, wherein the mass ratio of the silicone-free polyether defoamer to polyethylene glycol diacrylate is between 1 / 200 and 1 / 300.

[0064] S208: Grind the original solution for 2 hours. The particle size of the carbon black particles after grinding is between 30nm and 70nm.

[0065] S209: The ground solution is applied to the surface of the carrier film to form a coating.

[0066] S210: Dry the coated carrier film at a temperature ranging from 70°C to 90°C for 0.5 to 1.5 hours; irradiate the dried coated carrier film with ultraviolet light for 3 to 15 minutes; after ultraviolet irradiation, detach the coating from the carrier film to obtain the prepared black film.

[0067] The method for preparing the black film described in this application is simple, allowing the black film to directly contact the printing plate. It only requires mixing organic reagents in a fixed ratio and finely grinding the carbon black particles. Furthermore, the organic reagents used all possess good water solubility, and water is used as the solvent throughout the entire process. Even after the black film has cured, it retains good water solubility and can be removed by washing it with water along with the unexposed water-soluble resin during subsequent cleaning.

[0068] In some possible designs, the relative molecular mass of polyethylene glycol is between 1,000 and 3,000, and the concentration of polyethylene glycol aqueous solution is between 40% and 60%.

[0069] In this embodiment, the relative molecular mass of polyethylene glycol (PEG) is between 1000 and 3000, and the concentration of the PEG aqueous solution is between 40% and 60%. The molecular mass of PEG directly determines its molecular size. An excessively large relative molecular mass prevents PEG from completely coating the carbon black particles, while an excessively small relative molecular mass may result in PEG failing to coat the carbon black particles or forming a thin coating film that is too thin, failing to achieve effective coating. Setting the PEG aqueous solution concentration between 40% and 60% ensures that PEG is evenly distributed in the water mist during subsequent mist formation, thereby guaranteeing effective coating of the carbon black particles. Specifically, the relative molecular mass of PEG is chosen to be 1500, and the concentration of the PEG aqueous solution is 50%.

[0070] In some possible designs, the mass ratio of polyethylene glycol diacrylate to methoxy polyethylene glycol acrylate is between 200:3 and 200:1, the mass ratio of polyethylene glycol diacrylate to polyacrylate is between 5:2 and 5:1, the relative molecular mass of polyethylene glycol diacrylate is between 4000 and 10000, the relative molecular mass of polyacrylate is between 500 and 2000, and the relative molecular mass of methoxy polyethylene glycol acrylate is between 300 and 3000.

[0071] In this embodiment, polyethylene glycol diacrylate (PEG) is water-soluble and remains soluble after photopolymerization, acting as a film-forming and adhesive agent with high strength. Polyacrylate, while having lower strength, possesses good adhesion and elasticity, assisting in film formation and improving film quality. Methoxylated PEG is water-soluble and used for UV-initiated polymerization. The entire material system is based on acrylates, simplifying the system and reducing material incompatibility. Since PEG is the main film-forming component, its appropriate molecular weight determines the smoothness of the formed black film. Polyacrylate acts as an adhesive aiding film formation, requiring a suitable proportion and lower molecular weight to ensure reinforcement of adhesion and elasticity. Methoxylated PEG's role is to initiate polymerization; therefore, a suitable proportion and molecular weight are needed to ensure its complete effect throughout the film, resulting in a good forming effect. The proportion of polyacrylate is adjusted based on the viscosity of the black film, while the proportion of methoxylated PEG is adjusted according to the UV polymerization process. Specifically, take 100g of polyethylene glycol diacrylate 5000, 20g of polymethyl acrylate 1000 and 1.5g of methoxy polyethylene glycol acrylate 2000, stir and dissolve in 500ml of deionized water to form a mixture.

[0072] In some possible designs, the raw solution is milled for 2 hours, and the particle size of the milled carbon black particles is between 30nm and 70nm.

[0073] In this embodiment, the raw slurry needs to be ground for 2 hours to ensure that the particle size of the ground carbon black particles is between 30 nm and 70 nm, thereby ensuring good distribution of carbon black particles in the black film and guaranteeing the uniformity of the black film. Specifically, the particle size of the ground carbon black particles is 60 nm.

[0074] In some possible designs, the coated carrier film is dried at a temperature ranging from 70°C to 90°C for a time between 0.5 and 1.5 hours; the dried coated carrier film is then irradiated with ultraviolet light for a time between 3 and 15 minutes.

[0075] In this technology, the coated carrier film needs to be dried. To ensure drying effectiveness, the drying temperature range for moisture evaporation is 70℃ to 90℃, and the drying time is between 0.5 hours and 1.5 hours. After dehydration, the coating needs to be irradiated with ultraviolet light to polymerize the organic reagents and form a black film.

[0076] The irradiation time is between 3 and 15 minutes. The irradiation time depends on the efficiency of ultraviolet light. Excessive irradiation time will lead to a greater shrinkage rate of the black film, affecting production efficiency.

[0077] In some possible designs, the polyacrylate includes alkyl groups, wherein the number of carbon atoms in the alkyl group does not exceed 3.

[0078] In this embodiment, the polyacrylate includes: polymethyl acrylate, polyethyl acrylate, and polypropyl acrylate. Specifically, the number of carbon atoms in the alkyl group of the polyacrylate is limited to no more than 3. Because polyacrylates need to have good adhesion and elasticity, but relatively poor strength, an excessive number of carbon atoms would reduce adhesion and elasticity. Therefore, the number of carbon atoms in the alkyl group is limited to no more than 3 to ensure adhesion and elasticity.

[0079] In some possible designs, when methoxy polyethylene glycol acrylate is dissolved in deionized water, the temperature of the deionized water is between 20°C and 40°C.

[0080] In this embodiment, methoxy polyethylene glycol acrylate is used to initiate polymerization; therefore, the appropriate temperature will determine the polymerization effect. Temperatures that are too high or too low will result in poor polymerization and difficulty in forming the black film. When methoxy polyethylene glycol acrylate is dissolved in deionized water at a temperature of 20°C to 40°C, the polymerization effect is ensured, resulting in more uniform black film imaging.

[0081] In some possible designs, the particle size of the pretreated carbon black particles is between 30 nm and 100 nm.

[0082] In this embodiment, the carbon black particles require fine grinding pretreatment to ensure that the pretreated carbon black particles are evenly distributed throughout the raw slurry and the formed black film, thereby guaranteeing the uniformity and light-blocking properties of the black film. Specifically, the pretreated carbon black particles have a particle size of 60 nm.

[0083] In some possible designs, the raw material is coated onto the surface of the carrier film, forming a coating with a thickness between 2 μm and 8 μm.

[0084] In this embodiment, the thickness of the coating determines the thickness of the black film. The black film needs good light-blocking properties, so the coating thickness needs to be set between 2μm and 8μm. Too thick a coating would be wasteful, while too thin a coating would not provide a good light-blocking effect. Specifically, the coating thickness is 3μm.

[0085] In some possible designs, the carrier membrane is a PEEK membrane.

[0086] In this embodiment, the carrier film is a PEEK film. PEEK film has excellent properties such as high temperature resistance and self-lubrication, and the prepared black film has low shrinkage after peeling.

[0087] In some possible designs, the shrinkage before and after the black film detaches is between 0.5% and 1%.

[0088] In this embodiment, the shrinkage before and after the black film detaches is between 0.5% and 1%. This ensures that the black film and the coating are essentially the same size, thus eliminating the need to calculate the coating size during the black film's fabrication. This reduces production costs.

[0089] In some possible designs, silicone-free polyether defoamers include: fatty alcohol defoamers.

[0090] In this embodiment, the silicone-free polyether defoamer includes a fatty alcohol defoamer. During the process of coating the raw slurry onto the carrier membrane, air bubbles may form in the membrane layer, affecting quality. Adding a fatty alcohol defoamer can prevent air bubbles from forming in the membrane layer, thereby improving the uniformity of the black film.

[0091] The second aspect of the present invention provides a black film, which is made by the preparation method of the black film provided in any embodiment of the first aspect of this application. Therefore, the black film provided by the present invention has all the beneficial effects of the preparation method of the black film provided in any embodiment of the first aspect of the present invention, which will not be repeated here.

[0092] The black-and-white density value D of the black film provided by this invention is between 0 and 0.06. The black-and-white density of the black film determines the light-blocking rate. The black-and-white density value D of the black film formed in this application is between 0 and 0.06, which ensures that the generated black film has a good light-blocking effect.

[0093] In this invention, the term "multiple" refers to two or more unless otherwise explicitly defined. The terms "installed," "connected," "linked," and "fixed," etc., should be interpreted broadly. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "linked" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0094] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0095] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a black film, characterized in that, include: A polyethylene glycol aqueous solution is prepared by mixing polyethylene glycol and deionized water, and the polyethylene glycol aqueous solution is atomized to form a polyethylene glycol water mist. The pretreated carbon black particles are brought into full contact with the polyethylene glycol water mist to generate carbon black particles coated with the polyethylene glycol. The carbon black particles coated with the polyethylene glycol were freeze-dried. Under yellow light, polyethylene glycol diacrylate, polyacrylate and methoxy polyethylene glycol acrylate are dissolved in deionized water to form a mixture. Freeze-dried carbon black particles are added to the mixture and stirred. A silicone-free polyether defoamer is added to the mixture and stirred to generate a stock solution. The stock solution is then ground and coated onto the surface of a carrier film to form a coating. The carrier film with the coating is then dried. The dried carrier film with the coating is irradiated with ultraviolet light; After irradiation with ultraviolet light, the coating is detached from the carrier film to obtain the prepared black film.

2. The method for preparing the black film according to claim 1, characterized in that, The polyacrylate includes at least one of polymethyl acrylate, polyethyl acrylate, and polypropyl acrylate.

3. The method for preparing the black film according to claim 1, characterized in that, The mass ratio of polyethylene glycol diacrylate to methoxy polyethylene glycol acrylate is greater than or equal to 200:3 and less than or equal to 200:1; the mass ratio of polyethylene glycol diacrylate to polyacrylate is greater than or equal to 5:2 and less than or equal to 5:1; the relative molecular mass of polyethylene glycol diacrylate is greater than or equal to 4000 and less than or equal to 10000; the relative molecular mass of polyacrylate is greater than or equal to 500 and less than or equal to 2000; and the relative molecular mass of methoxy polyethylene glycol acrylate is greater than or equal to 300 and less than or equal to 3000.

4. The method for preparing the black film according to claim 1, characterized in that, The polyethylene glycol has a relative molecular mass greater than or equal to 1000 and less than or equal to 3000, and the concentration of the polyethylene glycol aqueous solution is greater than or equal to 40% and less than or equal to 60%.

5. The method for preparing the black film according to claim 1, characterized in that, When the methoxy polyethylene glycol acrylate is dissolved in deionized water, the temperature of the deionized water is greater than or equal to 20°C and less than or equal to 40°C.

6. The method for preparing the black film according to claim 1, characterized in that, The pretreated carbon black particles have a particle size greater than or equal to 30 nm and less than or equal to 100 nm; and / or The carbon black particles after grinding have a particle size greater than or equal to 30 nm and less than or equal to 70 nm.

7. The method for preparing the black film according to any one of claims 1 to 6, characterized in that, The stock solution is coated on the surface of the carrier film to form a coating with a thickness greater than or equal to 2 μm and less than or equal to 8 μm; and / or The carrier membrane is a PEEK membrane.

8. The method for preparing the black film according to any one of claims 1 to 6, characterized in that, When drying the carrier film with the coating, the drying temperature is greater than or equal to 70°C and less than or equal to 90°C, and the drying time is greater than or equal to 0.5 hours and less than or equal to 1.5 hours.

9. The method for preparing the black film according to any one of claims 1 to 6, characterized in that, The shrinkage of the black film before and after detachment is greater than or equal to 0.5% and less than or equal to 1%.

10. The method for preparing the black film according to any one of claims 1 to 6, characterized in that, The mass ratio of the silicone-free polyether defoamer to the polyethylene glycol diacrylate is greater than or equal to 1 / 300 and less than or equal to 1 / 200. and / or The silicone-free polyether defoamers include: fatty alcohol defoamers.

11. The method for preparing the black film according to any one of claims 1 to 6, characterized in that, When the dried carrier film with the coating is irradiated with ultraviolet light, the irradiation time of the ultraviolet light is greater than or equal to 3 minutes and less than or equal to 15 minutes.

12. A black film, characterized in that, The black film is prepared using the method for preparing a black film as described in any one of claims 1 to 11.

13. The black film according to claim 12, characterized in that, The black-white density value D of the black film is greater than or equal to 0 and less than or equal to 0.06.

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