Recovery Method and System of PVDF Slurry

Abstract

An embodiment of the present application provides a method and system for recycling PVDF slurry. The method for recycling PVDF slurry includes: if a target substrate is coated with a first PVDF slurry and N cleaning materials, collecting first waste outside the target substrate, where the cleaning materials are used to remove a part of the first PVDF slurry on the target substrate during the coating process, the first PVDF slurry includes M solvents, N≥1 and N is an integer, M≥1 and M is an integer; if the types of at least one of the N cleaning materials are all different from the types of the M solvents in the first PVDF slurry, removing the cleaning materials contained in the first waste to obtain second waste, and using the second waste for slurry preparation treatment to obtain recycled PVDF slurry. This solution can achieve the recycling of PVDF slurry.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of material recycling, and particularly to a method and a system for recycling PVDF slurry. Background Art

[0002] Polyvinylidene fluoride (PVDF) and its copolymers are polycrystalline polymer materials. After polarization treatment, they have good piezoelectric properties. PVDF materials have the advantages of light weight, flexibility, and can be prepared in large areas. Compared with traditional piezoelectric ceramic materials, they have a higher piezoelectric voltage coefficient, more easily matched acoustic impedance, and are compatible with semiconductor solution processes. Nowadays, PVDF materials have been widely used in various ultrasonic transducers. In particular, they can be used to fabricate ultrasonic biometric sensors.

[0003] In the manufacturing process of manufacturing ultrasonic sensors using PVDF materials, taking the 12-inch semiconductor silicon process as an example, generally through the spin coating process, the PVDF slurry with a certain viscosity and solid content is rotated by a rotating device. Under the action of centrifugal force, a uniform film layer is formed on the silicon-based substrate. To ensure the surface uniformity of the film layer, the spin coating nozzle usually spits out an excessive amount of PVDF slurry. For a 12-inch substrate, to form a dry film at the micron level, at least 20 - 40 ml of PVDF slurry needs to be spit out at one time, but in fact, only 5% - 10% of it is finally deposited on the silicon-based surface. Most of the PVDF slurry is thrown out during rotation: part of it adheres to the wall of the spin coating device, and the other part follows the cleaning solvent (i.e., the cleaning material) and is discharged together through the pipeline into the waste bucket.

[0004] However, the raw material cost of semiconductor-grade PVDF slurry is very high. Therefore, it is necessary to recycle the PVDF slurry, otherwise it will cause a large amount of waste. In addition, in the spin coating process, generally, the edge cleaning liquid and / or back cleaning liquid for cleaning the silicon-based substrate are used to clean part of the PVDF slurry, so that the thrown-out PVDF slurry is mixed with cleaning materials such as the edge cleaning liquid and back cleaning liquid. Therefore, how to recycle the PVDF slurry in the case where the PVDF slurry is mixed with cleaning materials such as the edge cleaning liquid and back cleaning liquid has also become a technical problem to be solved. Therefore, a new technical solution is needed to at least partially improve such problems. Summary of the Invention

[0005] To solve the above problems, the embodiments of the present application provide a method and a system for recycling PVDF slurry to at least partially solve the above problems.

[0006] According to one aspect of the present application, a method for recycling PVDF slurry is provided, including:

[0007] If the target substrate is coated with the first PVDF slurry and N cleaning materials, and the first waste outside the target substrate is collected, where the cleaning materials are used to remove part of the first PVDF slurry on the target substrate during the coating process, the first PVDF slurry includes M solvents, N≥1 and N is an integer, M≥1 and M is an integer;

[0008] If the types of at least one of the N cleaning materials are all different from the types of the M solvents in the first PVDF slurry, the cleaning materials contained in the first waste are removed to obtain a second waste, and the second waste is used for slurry preparation to obtain a regenerated PVDF slurry.

[0009] In some alternative embodiments, removing the cleaning materials contained in the first waste to obtain a second waste includes: performing a calcination treatment on the first waste to remove the cleaning materials contained in the first waste, and obtaining the second waste in the form of powder.

[0010] In some alternative embodiments, using the second waste for slurry preparation to obtain a regenerated PVDF slurry includes: measuring the powder parameters of the second waste in the form of powder, and using the second waste whose powder parameters meet the first predetermined condition for slurry preparation to obtain a regenerated PVDF slurry, where the powder parameters include at least one of the content of PVDF and its copolymers, Curie temperature, melting point, and melt flow rate of thermoplastics.

[0011] In some alternative embodiments, the first waste includes: solid waste formed by solidification of the first PVDF slurry and the cleaning materials, and / or slurry waste formed by mixing the first PVDF slurry and the cleaning materials.

[0012] In some alternative embodiments, the method further includes: if the types of the N cleaning materials are all the same as the types of at least one of the M solvents in the first PVDF slurry, using the first waste for slurry preparation to obtain a regenerated PVDF slurry.

[0013] In some alternative embodiments, for the solid waste in the first waste,

[0014] using the first waste for slurry preparation to obtain a regenerated PVDF slurry includes: dissolving the solid waste with the solvent of the first PVDF slurry to obtain a second PVDF slurry; adjusting the viscosity and PVDF solid content of the second PVDF slurry within a predetermined range to obtain a regenerated PVDF slurry; or,

[0015] Performing sizing treatment using the first waste material to obtain a recycled PVDF slurry includes: calcining the solid waste material to obtain a third waste material in powder form; and performing sizing treatment using the third waste material to obtain a recycled PVDF slurry.

[0016] In some alternative embodiments, for the slurry waste material in the first waste material,

[0017] Performing sizing treatment using the first waste material to obtain a recycled PVDF slurry includes: adjusting the viscosity and PVDF solid content of the slurry waste material to within a predetermined range to obtain a recycled PVDF slurry; or,

[0018] Performing sizing treatment using the first waste material to obtain a recycled PVDF slurry includes: calcining the slurry waste material to obtain a fourth waste material in powder form; and performing sizing treatment using the fourth waste material to obtain a recycled PVDF slurry.

[0019] In some alternative embodiments, the method further includes: filtering the recycled PVDF slurry to remove at least some impurities in the recycled PVDF slurry.

[0020] In some alternative embodiments, the method further includes: determining whether the viscosity and PVDF solid content of the recycled PVDF slurry after filtering treatment meet a second predetermined condition; if the second predetermined condition is met, taking a sample of the recycled PVDF slurry after filtering treatment and a substrate sample to perform a coating test on the substrate sample using the sample of the recycled PVDF slurry, and determining whether the film layer parameters of the film layer formed by the sample of the recycled PVDF slurry on the substrate sample after the coating test meet a third predetermined condition, where the film layer parameters include at least one of the thickness of the film layer, the thickness uniformity of the film layer, the piezoelectric properties of the film layer after polarization, and the optical properties of the film layer; if the third predetermined condition is met, using the recycled PVDF slurry after filtering treatment as the finished PVDF slurry.

[0021] In some alternative embodiments, the cleaning material includes at least one of an edge washing liquid and a back washing liquid.

[0022] According to another aspect in the embodiments of the present application, a recycling system for PVDF slurry is provided, including:

[0023] A collection unit for collecting the first waste material outside the target substrate if the target substrate is coated with a first PVDF slurry and N cleaning materials, where the cleaning materials are used to remove a part of the first PVDF slurry on the target substrate during the coating process, the first PVDF slurry includes M solvents, N≥1 and N is an integer, M≥1 and M is an integer;

[0024] A slurry preparation unit, which is configured to, if the types of at least one cleaning material among the N types of cleaning materials are all different from the types of the M solvents in the first PVDF slurry, remove the cleaning materials contained in the first waste to obtain a second waste, and use the second waste for slurry preparation to obtain a regenerated PVDF slurry.

[0025] In summary, for the PVDF slurry recovery solution in the embodiments of the present application, on the one hand, if the first PVDF slurry and N types of cleaning materials are used to coat a target substrate, and the first waste outside the target substrate is collected, and if the types of at least one cleaning material among the N types of cleaning materials are all different from the types of the M solvents in the first PVDF slurry, then the cleaning materials contained in the first waste are removed to obtain a second waste, and the second waste is used for slurry preparation to obtain a regenerated PVDF slurry. Therefore, through this PVDF slurry recovery solution, the PVDF slurry can be effectively recovered, reducing the waste of PVDF materials, improving the utilization rate of PVDF slurry in the coating process (including but not limited to spin coating process), and effectively reducing costs. On the other hand, in this recovery solution, if the types of at least one cleaning material among the N types of cleaning materials are all different from the types of the M solvents in the first PVDF slurry, the cleaning materials contained in the first waste are removed to obtain a second waste, and the second waste is used for slurry preparation to obtain a regenerated PVDF slurry. Therefore, through this PVDF slurry recovery solution, the PVDF slurry can be more reasonably recovered in the case of the mixture of PVDF slurry and cleaning materials, improving the effect of recovering the PVDF slurry. Description of the Drawings

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings.

[0027] Figure 1 Shows a flowchart of an exemplary PVDF slurry recovery method according to the present application.

[0028] Figure 2 Shows a schematic process diagram of an exemplary spin coating process using PVDF slurry according to the present application.

[0029] Figure 3 Shows another schematic process diagram of an exemplary spin coating process using PVDF slurry according to the present application.

[0030] Figure 4The flowchart of another exemplary PVDF slurry recovery method according to the present application is shown.

[0031] Figure 5 The sub - flowchart of an exemplary quality inspection step of the PVDF slurry recovery method according to the present application is shown.

[0032] Figure 6 The flowchart of yet another exemplary PVDF slurry recovery method according to the present application is shown.

[0033] Figure 7 The flowchart of still another exemplary PVDF slurry recovery method according to the present application is shown.

[0034] Figure 8 The block diagram of an exemplary PVDF slurry recovery system according to the present application is shown. Detailed implementation manners

[0035] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art shall fall within the scope protected by the embodiments of the present application.

[0036] In order to at least partially improve the problems existing in the prior art, according to one aspect of the present application, a PVDF slurry recovery method is provided. Figure 1 The flowchart of an exemplary PVDF slurry recovery method according to the present application is shown. Refer to Figure 1 As shown, the PVDF slurry recovery method includes the following steps S102 and S104. Specifically:

[0037] Step S102: If the target substrate is coated with the first PVDF slurry and N cleaning materials, collect the first waste outside the target substrate, where the cleaning materials are used to remove part of the first PVDF slurry on the target substrate during the coating process. The first PVDF slurry includes M solvents, N≥1 and N is an integer, M≥1 and M is an integer.

[0038] In the present application, the coating method of coating the target substrate with the first PVDF slurry and N cleaning materials includes, but is not limited to, the spin - coating process. In addition to the spin - coating process, it can also be other coating methods, which are not limited in the present application. For the convenience of description, the spin - coating process will be used for description hereinafter.

[0039] In this application, the first PVDF slurry includes M solvents, where M ≥ 1 and M is an integer. Specifically, the first PVDF slurry is a slurry prepared by mixing a certain proportion of PVDF material (such as PVDF powder) with M solvents under certain temperature conditions. Generally, the first PVDF slurry has a relatively high viscosity and volatility.

[0040] In this application, the types of the M solvents are not restricted and can be selected according to needs. For example, the types of solvents include, but are not limited to, polar ketones, esters, acetates, carbonate solvents, etc. Specifically, when M = 1, that is, the first PVDF slurry includes one solvent, a certain amount of PVDF powder material is dissolved in this solvent to obtain it; when M > 1, that is, the first PVDF slurry includes multiple solvents, the first PVDF slurry can be obtained by mixing a certain proportion of the M solvents and then dissolving a certain amount of PVDF material in the mixed M solvents, or the first PVDF slurry can also be obtained by sequentially pouring the M solvents into a certain amount of PVDF material and then dissolving the PVDF powder material in the mixed M solvents. Of course, these preparation processes are not restricted in this application, and only examples for easy understanding are given here.

[0041] For the first PVDF slurry, different combinations of PVDF powder type, solvent type, preparation conditions, solid content, viscosity, etc. will affect the PVDF coating effect, film formation quality, film layer thickness, microscopic morphology, PVDF crystal phase, etc., and will ultimately be reflected in the piezoelectric coefficient and product performance of the PVDF film formed by the first PVDF slurry.

[0042] In this application, the PVDF material contained in the first PVDF slurry can be PVDF (Polyvinylidene fluoride) and its copolymer materials. For example, it can include: poly(vinylidene fluoride - trifluoroethylene) copolymer (PVDF-TrFE, Poly(vinylidene fluoride-trifluoroethylene), common molar ratios 80 / 20, 75 / 25, 70 / 30, 55 / 45), poly(vinylidene fluoride - trifluoroethylene - chlorotrifluoroethylene) copolymer (PVDF-TrFE-CTFE, Poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene)), and poly(vinylidene fluoride - trifluoroethylene - chlorofluoroethylene) copolymer (PVDF-TrFE-CFE, Poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene)), etc.

[0043] In this application, the target substrate can be the target for coating the first PVDF material (e.g., spin coating). After the coating is completed, semiconductor devices can be produced using this target substrate. The material of the target substrate is not limited in this application. Optionally, for example, it can be a silicon-based substrate (e.g., the silicon-based substrate can be a silicon-based wafer), or a glass substrate (e.g., the glass substrate can be a glass wafer), etc. In addition, the size of the target substrate is not limited in this application. Taking the silicon-based substrate as an example, it can be a 6-inch, 8-inch, or 12-inch silicon-based substrate. For the sake of convenience of description, the target substrate is described as a silicon-based substrate in the following text.

[0044] In this application, the cleaning material is used to remove part of the first PVDF slurry on the target substrate during the coating process and can assist in coating the target substrate. The cleaning material in this application can be a liquid material of the same type as the solvent of the first PVDF slurry, or a liquid material of a different type from the solvent of the first PVDF slurry, subject to the actual coating requirements, which are not limited in this application. N cleaning materials can be used to remove different parts of the first PVDF slurry on the target substrate, where N≥1 and N is an integer.

[0045] Optionally, the cleaning material includes at least one of an edge bead removal (EBR) liquid and a back side clean (BSC) liquid. Among them, the edge bead removal liquid can remove part of the first PVDF slurry on the edge of the target substrate, and the back side clean liquid can remove part of the first PVDF slurry on the back of the target substrate. Of course, for the cleaning material being the edge bead removal liquid, it can be a liquid material of the same type as the solvent of the first PVDF slurry, or a liquid material of a different type from the solvent of the first PVDF slurry, subject to the actual coating requirements, which are not limited in this application; for the cleaning material being the back side clean liquid, it can be a liquid material of the same type as the solvent of the first PVDF slurry, or a liquid material of a different type from the solvent of the first PVDF slurry, subject to the actual coating requirements, which are not limited in this application.

[0046] In this application, the first waste can be generated due to the coating process. Optionally, the first waste includes: solid waste formed by the solidification of the first PVDF slurry and the cleaning material, and slurry waste formed by the mixing of the first PVDF slurry and the cleaning material.

[0047] Specifically, taking spin coating as an example, to ensure the surface uniformity of the PVDF film layer on the target substrate, the spin coating nozzle usually spits out an excessive amount of the first PVDF slurry. Generally, the first PVDF slurry has a relatively high viscosity and volatility. During the spin coating process, most of the first PVDF slurry that is thrown out of the target substrate adheres to the inner wall of the spin coating device, and a small part flows down along the inner wall and is discharged into the waste liquid bucket together with the cleaning materials (such as edge washing liquid and back washing liquid, etc.). For example, for a 12-inch target substrate, to form a micron-level PVDF dry film, at least 20 - 40 ml of the first PVDF slurry needs to be spit out at one time, but in fact, only 5% - 10% of it is finally deposited on the surface of the target substrate. Most of the first PVDF slurry is thrown out of the target substrate during rotation: a part of the first PVDF slurry adheres to the inner wall of the spin coating device following the cleaning materials (such as edge washing liquid and back washing liquid, etc.). After the solvent has basically volatilized, these first PVDF slurry and cleaning materials solidify on the inner wall of the spin coating device, thus forming the solid waste in the first waste (the solid waste can be, but is not limited to, dry film-like, block-like, etc. For example, the dry film-like can be close to the plastic film state, and the dry film-like solid waste can be residues / spread on the inner wall of the spin coating device); another part of the first PVDF slurry follows the cleaning materials (such as edge washing liquid and back washing liquid, etc.) and is discharged into the waste bucket together through the pipeline. These first PVDF slurry and cleaning materials are mixed, thus forming the slurry waste in the first waste.

[0048] In this application, the collection of the first waste outside the target substrate can be carried out manually or automatically by a machine, and this application does not impose any restrictions. For example, for the solid waste in the first waste, the solid waste can be removed from the inner wall of the spin coating device and collected with a container to complete the collection. For the slurry waste in the first waste, it can be directly taken from the waste bucket. It should be understood that this is only an exemplary explanation of this application and does not serve as any limitation.

[0049] Refer to Figure 2 A simple description of the process of the spin coating process using PVDF slurry in this application is as follows. Figure 2 Fig. shows a schematic diagram of the process of an exemplary spin coating process using PVDF slurry according to this application. Refer to Figure 2As shown, it includes: a spin coater 1000, a PVDF slurry incoming material tank 1001, a PVDF slurry supply tank 1002, a waste liquid bucket 1003, a pipeline 1004, a filter 1005, and a target substrate 1015. The spin coater 1000 includes a spin coating nozzle 1006, the cup wall 1007 of the spin coater, a spin coating mask 1008, a side washing component 1009, a back washing component 1010, etc. Among them, the target substrate 1015 (such as a silicon-based substrate) is arranged on the spin coater 1000, and the spin coater 1000 can drive the target substrate 1015 to rotate; the PVDF slurry incoming material tank 1001 and the PVDF slurry supply tank 1002 are connected to the spin coating nozzle 1006 through the pipeline 1004 and the filter 1005. The spin coating nozzle 1006 is located above the target substrate 1015. The PVDF slurry incoming material tank 1001 is used for storing and replenishing the first PVDF slurry. The PVDF slurry supply tank 1002 is used for obtaining and storing the first PVDF slurry from the PVDF slurry incoming material tank 1001 and transporting the first PVDF slurry to the spin coating nozzle 1006. The spin coating nozzle 1006 sprays the first PVDF slurry onto the target substrate 1015 driven by the spin coater 1000 to rotate (for easy representation, Figure 2 the first PVDF slurry sprayed by the spin coating nozzle 1006 is represented by the reference numeral 1011); the side washing component 1009 is used for spraying a side washing liquid (i.e., a cleaning material, for easy representation, Figure 2 the side washing liquid is represented by the reference numeral 1012) during the spin coating process to remove a part of the first PVDF slurry on the edge of the target substrate 1015; the back washing component 1010 is used for spraying a back washing liquid (i.e., another cleaning material, for easy representation, Figure 2 the back washing liquid is represented by the reference numeral 1013) during the spin coating process to remove a part of the first PVDF slurry on the back of the target substrate 1015; during the spin coating process, a PVDF wet film 1016 is formed on the target substrate 1015, and the slurry 1014 (including part of the first PVDF slurry, the side washing liquid, and the back washing liquid) is thrown out of the target substrate 1015 during the spin coating process. A part of the slurry 1014 solidifies on the spin coating mask 1008 to form a dry film waste 1017 including PVDF; the spin coating mask 1008 covers above the cup wall 1007 of the spin coater, which can facilitate the separation of the dry film waste 1017 (i.e., the solid waste in the first waste) and at the same time avoid introducing impurities or possibly precipitated elements on the cup wall 1007 of the spin coater to contaminate the solid waste (of course, referring to Figure 3 the schematic diagram of another exemplary process of the spin coating process using PVDF slurry shown. In another alternative embodiment, if the material of the cup wall 1007 of the spin coater does not affect the recovery of the dry film 1017, the spin coating mask 1008 may not be required; therefore, for Figure 3For the embodiments, the wall of the aforementioned spin coating device may be the cup wall 1007 of the spin coater, while for Figure 2 For the embodiments, the wall of the aforementioned spin coating device may be the spin coating mask 1008.); Optionally, the surface of the spin coating mask 1008 may be made of a chemically inert material, which may be PTFE (polytetrafluoroethylene) or FPA resin (tetrafluoroethylene-perfluoroalkoxy ether copolymer resin) with acid and alkali resistance, anti-sticking property, and chemical resistance, etc.; Another part of the slurry 1014 is discharged through a pipeline into the waste liquid bucket 1003 and collected by the waste liquid bucket 1003 (this another part of the slurry 1014 is the slurry waste in the first waste); The PVDF wet film 1016 on the target substrate 1015 finally forms a PVDF dry film, and the spin coating process is completed. Figure 3 The process schematic diagram of the spin coating process in Figure 2 differs only in that the spin coating mask 1008 is not provided, so it can be understood with reference to Figure 2 the description, and will not be elaborated here. It should be understood that any description of the process of the spin coating process in Figure 2 and Figure 3 is only for facilitating the understanding of this embodiment and does not impose any limitation on the embodiments of this application.

[0050] Step S104: If the types of at least one cleaning material among the N types of cleaning materials are all different from the types of the M solvents in the first PVDF slurry, then the cleaning material contained in the first waste is removed to obtain a second waste, and the second waste is used for slurry preparation to obtain a regenerated PVDF slurry.

[0051] For ease of understanding, a simple example is given to illustrate step S104. For example, N = 2, M = 5, the two cleaning materials are edge washing liquid and back washing liquid, and the first PVDF slurry has a total of five solvents. If the types of the edge washing liquid are all different from the types of the five solvents and the type of the back washing liquid is the same as one of the types of the solvents, or the types of the back washing liquid are all different from the types of the five solvents and the type of the edge washing liquid is the same as one of the types of the solvents, or the types of the edge washing liquid are all different from the types of the five solvents and the types of the back washing liquid are all different from the types of the five solvents, then the cleaning materials contained in the first waste are removed to obtain the second waste, and the second waste is used for slurry preparation to obtain the recycled PVDF slurry. The rest of the similar situations can be deduced by analogy. The reason for such treatment is that if at least one of the N cleaning materials has a type that is different from the types of the M solvents in the first PVDF slurry, it is equivalent to that the cleaning materials contained in the first waste are impurities of the PVDF materials contained in the first waste. When recycling the PVDF slurry, the cleaning materials cannot be utilized. Therefore, in this case, in the present application, the cleaning materials contained in the first waste are removed to obtain the second waste, and the second waste is used for slurry preparation to obtain the recycled PVDF slurry, which can realize more reasonable recycling of the PVDF slurry in the case of mixing of the PVDF slurry and the cleaning materials and reduce the impurities of the recycled PVDF slurry obtained by recycling.

[0052] Based on this, in the PVDF slurry recycling method of the present application through steps S102 - S104, on the one hand, since if the first PVDF slurry and N cleaning materials are used to coat the target substrate, and the first waste outside the target substrate is collected, and if at least one of the N cleaning materials has a type that is different from the types of the M solvents in the first PVDF slurry, then the cleaning materials contained in the first waste are removed to obtain the second waste, and the second waste is used for slurry preparation to obtain the recycled PVDF slurry. Therefore, through this PVDF slurry recycling method, the PVDF slurry can be effectively recycled, the waste of PVDF materials is reduced, the utilization rate of the PVDF slurry in the coating process (including but not limited to the spin coating process) is improved, and the cost can be effectively reduced. On the other hand, since in this recycling method, if at least one of the N cleaning materials has a type that is different from the types of the M solvents in the first PVDF slurry, the cleaning materials contained in the first waste are removed to obtain the second waste, and the second waste is used for slurry preparation to obtain the recycled PVDF slurry. Therefore, through this PVDF slurry recycling method, the PVDF slurry can be more reasonably recycled in the case of mixing of the PVDF slurry and the cleaning materials, and the effect of recycling the PVDF slurry is improved.

[0053] In this application, the second waste is subjected to pulp preparation treatment, which may be using the second waste as a raw material to prepare pulp, so as to obtain a recycled PVDF pulp that meets the requirements. For example, it may include at least one operation such as dissolution, dilution, concentration, etc. For example, in an optional embodiment described below, it will be introduced that the second waste may be in powder form. An optional way to perform pulp preparation treatment on the second waste may be to perform pulp preparation treatment in the same way as the original first PVDF pulp (for example, perform pulp preparation according to the component ratio of the original first PVDF pulp). Of course, performing pulp preparation treatment in the same way as the original first PVDF pulp is only an optional implementation method of this application. It is also possible to perform pulp preparation treatment in other pulp preparation methods to obtain a recycled PVDF pulp, and this application does not limit this here.

[0054] In this application, the specific manner of "removing the cleaning material contained in the first waste to obtain the second waste" in step S104 is not limited, and any suitable manner can be adopted to achieve it. In some optional embodiments, "removing the cleaning material contained in the first waste to obtain the second waste" includes: calcining the first waste to remove the cleaning material contained in the first waste to obtain the second waste in powder form.

[0055] Based on this, by calcining the first waste in this application, the cleaning material contained in the first waste can be effectively removed, and the second waste in powder form can be obtained, which is convenient for subsequent use of the second waste for pulp preparation treatment to obtain a recycled PVDF pulp.

[0056] It should be noted that in such an optional embodiment, for the solid waste and / or slurry waste in the first waste, the calcination treatment method can be used to remove the cleaning material contained in the first waste to obtain the second waste in powder form.

[0057] Optionally, taking the calcination treatment of the solid waste in the first waste as an example, the process and principle can be as follows: heating and calcining the solid waste (such as in the form of a dry film), and during the calcination process, enabling the residual cleaning materials (such as edge washing liquid, back washing liquid) in the solid waste (such as in the form of a dry film) to completely volatilize and degrade, so as to obtain the second waste in the form of powder. Optionally, taking the calcination treatment of the slurry waste in the first waste as an example, the process and principle can be as follows: heating and calcining the slurry waste, and during the calcination process, enabling the residual cleaning materials (such as edge washing liquid, back washing liquid) in the slurry waste to completely volatilize and degrade, so as to obtain the second waste in the form of powder. After that, at least part of the second waste in the form of powder obtained can be used for slurry preparation treatment according to the original slurry preparation method of the first PVDF slurry (such as slurry preparation with the component ratio of the original first PVDF slurry), to obtain the regenerated PVDF slurry. Of course, slurry preparation treatment according to the original slurry preparation method of the first PVDF slurry is only an optional implementation manner of this application, and slurry preparation treatment can also be carried out in other slurry preparation methods to obtain the regenerated PVDF slurry, which is not limited herein.

[0058] In some alternative embodiments, "using the second waste for slurry preparation treatment to obtain the regenerated PVDF slurry" in step S104 includes: measuring the powder parameters of the second waste in the form of powder, and using the second waste whose powder parameters meet the first predetermined condition for slurry preparation treatment to obtain the regenerated PVDF slurry, where the powder parameters include at least one of the content of PVDF and its copolymers, Curie temperature, melting point, and melt flow rate of thermoplastics.

[0059] Since the second waste in the form of powder is obtained by calcining the first waste to remove the cleaning materials contained in the first waste, most of the second waste in the form of powder is PVDF powder. In this application, when the powder parameters of the second waste in the form of powder are measured and it is determined that the powder parameters meet the first predetermined condition, it can be considered that the PVDF powder in the second waste can meet the required standards and can be used for slurry preparation to obtain the required regenerated PVDF slurry.

[0060] Optionally, the first preset condition can be set according to needs, and different value ranges can be set according to needs for different powder parameters. For example, when the measured powder parameters of the second waste are within the corresponding value ranges (such as the value ranges can be set as the value ranges that the PVDF powder in the first PVDF slurry should meet), it can be considered that the first predetermined condition is met.

[0061] Optionally, for the content of PVDF and its copolymers in the powder parameters, it can be measured by a copolymer content measurement method based on nuclear magnetic resonance hydrogen spectrum (H1NMR, Nuclear magnetic resonance); optionally, for the Curie temperature and melting point in the powder parameters, a Curie temperature and melting point measurement method based on differential scanning calorimetry (DSC, Differential scanning calorimeter) can be used for measurement; optionally, for the melt flow rate of thermoplastics in the powder parameters, a melt flow rate (MFI, Meltflow index) measurement method of thermoplastics under the ASTM-D1238 standard can be used for measurement. Through these measurement methods, various powder parameters of the second waste in powder form can be effectively measured to determine whether the powder parameters of the second waste in powder form meet the first predetermined conditions. It should be understood that the specific implementation of these measurement methods can refer to the relevant technologies and will not be elaborated here. Of course, these measurement methods are only optional examples, and other feasible methods can also be used in this application, which is not limited here.

[0062] Figure 4 FIG. shows a flowchart of another exemplary PVDF slurry recovery method according to the present application. Referring to Figure 4 As shown, in some alternative embodiments, the PVDF slurry recovery method further includes step S106.

[0063] Step S106: If the types of the N cleaning materials are all the same as at least one of the types of the M solvents in the first PVDF slurry, then use the first waste for slurry preparation to obtain a regenerated PVDF slurry.

[0064] For ease of understanding, step S106 will be described in combination with the aforementioned simple example. For example, N = 2, M = 5, the two cleaning materials are edge washing liquid and back washing liquid, and the first PVDF slurry has a total of five solvents. If the type of the edge washing liquid is the same as one of the types of the five solvents and the type of the back washing liquid is the same as one of the types of the solvents, the first waste is directly used for slurry preparation to obtain a regenerated PVDF slurry. Other similar situations can be deduced by analogy. The reason for such treatment is that if the types of the N cleaning materials are all the same as at least one of the types of the M solvents in the first PVDF slurry, it is equivalent to that the N cleaning materials contained in the first waste can be regarded not as impurities of the PVDF material contained in the first waste, but can all be used as solvents when recycling the PVDF slurry. Therefore, in this case, the present application directly uses the first waste for slurry preparation to obtain a regenerated PVDF slurry, which can improve the utilization rate of the cleaning materials in some embodiments, can more reasonably recycle the PVDF slurry in the case of mixing of the PVDF slurry and the cleaning materials, and reduce the impurities of the recycled regenerated PVDF slurry.

[0065] In the present application, using the first waste for slurry preparation may be using the first waste as a raw material to prepare a slurry, so as to obtain a regenerated PVDF slurry that meets the requirements. For example, it may include at least one operation such as dissolution, dilution, concentration, etc.

[0066] In the present application, the specific manner of "using the first waste for slurry preparation to obtain a regenerated PVDF slurry" in step S106 is not limited. In some alternative embodiments, for the solid waste in the first waste, "using the first waste for slurry preparation to obtain a regenerated PVDF slurry" in step S106 can be implemented by any one of the following methods A1 and A2. Specifically, in some alternative embodiments, method A1 includes the following two steps SA11 and SA12:

[0067] Step SA11: Using the solvent of the first PVDF slurry to dissolve the solid waste to obtain a second PVDF slurry.

[0068] Specifically, for the solid waste in the first waste, since the types of each cleaning material (such as edge washing liquid, back washing liquid) are the same as the types of the solvents of the first PVDF slurry, the present application uses the solvent of the first PVDF slurry to dissolve the solid waste. Then, the cleaning materials included in the solid waste can be used as solvents after dissolution, and the PVDF materials included in the solid waste are used as solutes, so as to obtain a second PVDF slurry.

[0069] Step SA12: Adjust the viscosity and PVDF solid content of the second PVDF slurry to within a predetermined range to obtain a regenerated PVDF slurry.

[0070] Since the viscosity and PVDF solid content of the second PVDF slurry obtained in step SA11 may not necessarily meet the requirements, in this step SA12, the viscosity and PVDF solid content of the second PVDF slurry need to be adjusted within a predetermined range, and after the adjustment is completed, a regenerated PVDF slurry is obtained.

[0071] In this application, the predetermined range can be set according to needs. For example, it can be set as the value range of the viscosity and PVDF solid content of the first PVDF slurry. That is, when the viscosity and PVDF solid content of the second PVDF slurry are respectively adjusted to the value range of the viscosity of the first PVDF slurry and the value range of the PVDF solid content of the first PVDF slurry, a regenerated PVDF slurry is obtained.

[0072] Optionally, in this application, step SA12 can adjust the viscosity and PVDF solid content of the second PVDF slurry within a predetermined range by diluting or concentrating the second PVDF slurry. For example, if the PVDF solid content and viscosity of the second PVDF slurry are too high, dilution treatment is performed; if the PVDF solid content and viscosity of the second PVDF slurry are too low, concentration treatment is performed until the solid content and viscosity of the second PVDF slurry meet the predetermined range (for example, the value range of the viscosity and PVDF solid content of the original first PVDF slurry).

[0073] Or, step SA12 can also use other methods to adjust the viscosity and PVDF solid content of the second PVDF slurry within a predetermined range, and this application does not limit this here.

[0074] Based on this, through the above method A1, this application can reasonably recycle the solid waste in the first waste to obtain a regenerated PVDF slurry.

[0075] Or, in some other alternative embodiments, method A2 includes the following two steps SA21 and SA22:

[0076] Step SA21: Calcine the solid waste to obtain a third waste in powder form.

[0077] Specifically, for the solid waste in the first waste, in addition to using the cleaning materials (such as edge washing liquid and back washing liquid) contained in the solid waste as solvents in method A1 of this application, the solid waste can also be directly calcined to remove the cleaning materials contained in the solid waste to obtain a third waste in powder form.

[0078] For this step SA21, its process and principle are basically similar to those in the aforementioned step S104, "calcining the first waste to remove the cleaning materials contained in the first waste and obtaining the second waste in powder form", that is, its process and principle can be: heating and calcining the solid waste (such as in the form of a dry film), and during the calcining process, making the residual cleaning materials (such as edge washing liquid and back washing liquid) in the solid waste (such as in the form of a dry film) completely volatilize and degrade, so as to obtain the third waste in powder form.

[0079] Step SA22: Perform pulp preparation treatment using the third waste to obtain a regenerated PVDF slurry.

[0080] Since the third waste in powder form is obtained by calcining the solid waste in the first waste to remove the cleaning materials contained in the solid waste, most of the third waste in powder form is PVDF powder.

[0081] After that, at least part of the third waste in powder form obtained can be used to perform pulp preparation treatment according to the pulp preparation method of the original first PVDF slurry (for example, performing pulp preparation according to the component ratio of the original first PVDF slurry) to obtain a regenerated PVDF slurry. Of course, performing pulp preparation treatment according to the pulp preparation method of the original first PVDF slurry is only an optional implementation manner of this application, and pulp preparation treatment can also be performed in other pulp preparation methods to obtain a regenerated PVDF slurry, which is not limited herein.

[0082] Based on this, through the above method A2, this application can reasonably recycle the solid waste in the first waste to obtain a regenerated PVDF slurry.

[0083] Further optionally, step SA22 may include: measuring the powder parameters of the third waste in powder form, and using the third waste whose powder parameters meet the predetermined conditions to perform pulp preparation treatment to obtain a regenerated PVDF slurry, where the powder parameters include at least one of the content of PVDF and its copolymer, Curie temperature, melting point, and melt flow rate of thermoplastic plastics. In this application, when the powder parameters of the third waste in powder form are measured and it is determined that the powder parameters meet the predetermined conditions, it can be considered that the PVDF powder in the third waste can meet the required standards and can be used for pulp preparation to obtain a regenerated PVDF slurry that meets the requirements. The predetermined conditions can be set according to needs, and different value ranges can be set according to needs for different powder parameters. For example, when the measured powder parameters of the third waste are within the corresponding value ranges (for example, this value range can be set to the value range that the PVDF powder in the first PVDF slurry should meet), it is considered to meet the predetermined conditions. For the measurement method of the powder parameters, reference can also be made to the relevant content in the aforementioned step S104 for understanding, and details will not be elaborated here.

[0084] In some alternative embodiments, for the slurry waste in the first waste, in the step S106 of "using the first waste for pulp preparation to obtain recycled PVDF slurry", any one of the following methods B1 and B2 can be adopted to implement it. Specifically, in some alternative embodiments, method B1 includes: adjusting the viscosity and PVDF solid content of the slurry waste within a predetermined range to obtain recycled PVDF slurry.

[0085] Specifically, for the slurry waste in the first waste, since the types of each cleaning material (such as edge washing liquid and back washing liquid) are the same as the type of the solvent of the first PVDF slurry, the cleaning materials included in the slurry waste can be used as solvents. Therefore, the viscosity and PVDF solid content of the slurry waste can be directly adjusted within a predetermined range to obtain recycled PVDF slurry whose viscosity and PVDF solid content can meet the requirements.

[0086] In this application, the predetermined range can be set according to needs. For example, it can be set as the value range of the viscosity and PVDF solid content of the first PVDF slurry. That is, when the viscosity and PVDF solid content of the slurry waste are respectively adjusted to the value range of the viscosity of the first PVDF slurry and the value range of the PVDF solid content of the first PVDF slurry, recycled PVDF slurry is obtained.

[0087] Optionally, in this application, method B1 can adjust the viscosity and PVDF solid content of the slurry waste within a predetermined range by diluting or concentrating the slurry waste. For example, if the PVDF solid content and viscosity of the slurry waste are too high, dilution treatment is carried out. If the PVDF solid content and viscosity of the slurry waste are too low, concentration treatment is carried out until the solid content and viscosity of the slurry waste meet the predetermined range (such as the value range of the viscosity and PVDF solid content of the original first PVDF slurry).

[0088] Alternatively, method B1 can also adopt other methods to adjust the viscosity and PVDF solid content of the slurry waste within a predetermined range, and this application does not limit it here.

[0089] Based on this, through the above method B1, this application can reasonably recycle the slurry waste in the first waste to obtain recycled PVDF slurry.

[0090] Alternatively, in some other alternative embodiments, method B2 includes the following two steps SB21 and SB22:

[0091] Step SB21: Calcinate the slurry waste to obtain the fourth waste in powder form.

[0092] Specifically, for the slurry waste in the first waste, in addition to using the cleaning materials (such as edge washing liquid and back washing liquid) contained in the slurry waste as solvents in Method B1 of the present application, the slurry waste can also be directly calcined to remove the cleaning materials contained in the slurry waste, obtaining the fourth waste in powder form.

[0093] For step SB21, its process and principle are basically similar to those of "calcining the first waste to remove the cleaning materials contained in the first waste and obtaining the second waste in powder form" in the aforementioned step S104. That is, its process and principle can be: heating and calcining the slurry waste, and during the calcination process, enabling the remaining cleaning materials (such as edge washing liquid and back washing liquid) in the slurry waste to completely volatilize and degrade, thereby obtaining the fourth waste in powder form.

[0094] Step SB22: Using the fourth waste for slurry preparation to obtain a regenerated PVDF slurry.

[0095] Since the fourth waste in powder form is obtained after calcining the slurry waste in the first waste to remove the cleaning materials contained in the slurry waste, most of the fourth waste in powder form is PVDF powder.

[0096] After that, at least part of the fourth waste in powder form obtained can be used for slurry preparation according to the slurry preparation method of the original first PVDF slurry (such as preparing the slurry according to the component ratio of the original first PVDF slurry) to obtain a regenerated PVDF slurry. Of course, preparing the slurry according to the slurry preparation method of the original first PVDF slurry is only an optional implementation method of the present application, and the regenerated PVDF slurry can also be obtained by using other slurry preparation methods. The present application does not limit this here.

[0097] Based on this, through the above Method B2, the present application can reasonably recycle the slurry waste in the first waste to obtain a regenerated PVDF slurry.

[0098] Further optionally, step SB22 may include: measuring powder parameters of the fourth waste in powder form, and performing pulp preparation treatment on the fourth waste whose powder parameters meet a predetermined condition to obtain a regenerated PVDF slurry, where the powder parameters include at least one of the content of PVDF and its copolymer, Curie temperature, melting point, and melt flow rate of thermoplastics. In the present application, when the powder parameters of the fourth waste in powder form are measured and it is determined that the powder parameters meet the predetermined condition, it can be considered that the PVDF powder in the fourth waste can meet the required standard and can be used for pulp preparation to obtain a regenerated PVDF slurry that meets the requirements. The predetermined condition can be set as needed, and different value ranges can be set as needed for different powder parameters. For example, when the powder parameters of the measured fourth waste are within the corresponding value range (for example, the value range can be set as the value range that the PVDF powder in the first PVDF slurry should meet), it can be considered that the predetermined condition is met. For the measurement method of the powder parameters, reference can be made to the relevant content in the foregoing step S104 for understanding, and details will not be elaborated here.

[0099] In some alternative embodiments, for the slurry waste in the first waste, before performing the step of "performing pulp preparation treatment on the first waste to obtain a regenerated PVDF slurry", the slurry waste can also be filtered first, so that the filtered slurry waste can be used for pulp preparation treatment to obtain a regenerated PVDF slurry. Based on this, at least some impurities (such as particulate matter, flocs, colloidal particles, etc.) in the slurry waste can be removed, so that the finally recovered regenerated PVDF slurry has fewer impurities and can better meet the requirements.

[0100] In some alternative embodiments, the method for recovering the PVDF slurry further includes: filtering the regenerated PVDF slurry to remove at least some impurities in the regenerated PVDF slurry.

[0101] Since the regenerated PVDF slurry may contain impurities such as particulate matter, flocs, and colloidal particles, the present application filters the obtained regenerated PVDF slurry to remove at least some impurities in the regenerated PVDF slurry, so that the regenerated PVDF slurry has fewer impurities and can better meet the requirements.

[0102] The present application does not limit the specific manner of the filtering treatment. In some exemplary embodiments, the filtering treatment can be performed using a cartridge filter. For example, the cartridge filter can use a cartridge filter with a cartridge porosity of 1 μm or 0.5 μm, and the filtering treatment can be performed under appropriate pressure. For example, the filtering treatment operation is performed under 2 atmospheric pressures to filter into a uniform slurry. Of course, the present application does not particularly limit the cartridge porosity and pressure of the filtering here, and can be selected as needed based on operability and filtering effect.

[0103] In some alternative embodiments, after the recycled PVDF slurry is subjected to a filtration process, the method for recycling the PVDF slurry further includes a quality inspection step. Figure 5 A sub - flow chart showing an exemplary quality inspection step of the method for recycling the PVDF slurry according to the present application is shown. Refer to Figure 5 As shown, the quality inspection step may include sub - steps S202, S204, and S206. Specifically:

[0104] Sub - step S202: Determine whether the viscosity and the PVDF solid content of the recycled PVDF slurry after the filtration process meet the second predetermined condition.

[0105] Specifically, in the present application, when the viscosity and the PVDF solid content of the recycled PVDF slurry after the filtration process meet the second predetermined condition, it can be considered that the viscosity and the PVDF solid content of the recycled PVDF slurry after the filtration process can meet the usage standard. If not, it is considered that they cannot meet the usage standard. In the present application, the method for measuring the viscosity and the PVDF solid content of the recycled PVDF slurry after the filtration process can be implemented with reference to the related art and will not be elaborated herein.

[0106] Optionally, the second predetermined condition can be set according to needs. For example, different value ranges can be set for the viscosity and the PVDF solid content (i.e., the solid content of PVDF and its copolymers in the slurry). For example, in one implementation, it can also be set to the value ranges of the viscosity and the PVDF solid content of the first PVDF slurry. For example, when the measured viscosity and PVDF solid content of the recycled PVDF slurry are both within the corresponding value ranges, it can be considered that the second predetermined condition is met.

[0107] Of course, the present application does not limit the value ranges of the viscosity and the PVDF solid content. Optionally, the value range of the viscosity can be specified as 500 mPaS to 3000 mPaS, and the value range of the PVDF solid content can be specified as 10 wt% to 30 wt%. In some of the alternative examples, the value range of the viscosity can be specified as 2000 ± 5% mPaS, that is, 1900 mPaS to 2100 mPaS. Optionally, the value range of the PVDF solid content can be specified as 15 ± 1 wt%, that is, 14 wt% to 16 wt%. Of course, these are only examples and are subject to actual needs, and the present application does not limit this here.

[0108] Sub-step S204: If the second predetermined condition is satisfied, samples of the regenerated PVDF slurry after filtration treatment and matrix samples are taken to perform a coating test on the matrix samples using the samples of the regenerated PVDF slurry, and it is determined whether the film layer parameters of the film layer formed by the samples of the regenerated PVDF slurry on the matrix samples after the coating test meet the third predetermined condition, where the film layer parameters include at least one of the thickness of the film layer, the thickness uniformity of the film layer, the piezoelectric properties of the film layer after polarization, and the optical properties of the film layer.

[0109] Specifically, when the second predetermined condition is satisfied, the present application performs a coating test (for example, it may include but is not limited to a spin coating test, which can be carried out according to needs). For example, the piezoelectric properties of the film layer after polarization may include but are not limited to the piezoelectric constant D33, and the optical properties of the film layer may include but are not limited to at least one of the film transmittance and haze. The matrix samples may be silicon-based matrix samples and / or glass matrix samples. Optionally, in order to comprehensively conduct quality inspection on the regenerated PVDF slurry, various types of matrix samples can be taken for separate tests. For different types of matrix samples, different film layer parameters can also be measured respectively. For example, the thickness of the film layer, the thickness uniformity of the film layer, and the piezoelectric properties of the film layer after polarization (such as the piezoelectric constant D33, etc.) are measured using silicon-based matrix samples and / or glass matrix samples, and the optical properties of the film layer (such as the film transmittance and haze, etc.) are measured using glass matrix samples.

[0110] Specifically, in the present application, when the film layer parameters of the film layer formed by the regenerated PVDF slurry samples meet the third predetermined condition, it can be considered that the film layer formed by the regenerated PVDF slurry after filtration treatment can meet the use standard. If not, it is considered that it cannot meet the use standard. In the present application, the methods for measuring each film layer parameter can be implemented with reference to related technologies and will not be elaborated here.

[0111] Optionally, the third predetermined condition can be set according to needs, and different value ranges can be set for different film layer parameters as required. For example, when the measured film layer parameters of the film layer formed by the regenerated PVDF slurry samples are within the corresponding value ranges, it can be considered that the third predetermined condition is satisfied.

[0112] Optionally, a silicon-based substrate (i.e., a silicon-based matrix sample, one of the matrix samples) is taken for spin coating test. A sample of the recycled PVDF slurry can be spin coated on the silicon-based substrate. After baking and crystallization, a film layer (dry film layer) is formed, and then the thickness of the film layer, the thickness uniformity of the film layer, and the piezoelectric properties (such as piezoelectric constant D33) of the film layer after polarization can be measured. For example, optionally, the value range of the thickness of the film layer can be set to 5um to 50um; optionally, the value range of the thickness uniformity of the film layer can be set to less than 10%; optionally, the value range of the piezoelectric constant D33 is set to be greater than 20 pC / N. Of course, these are only examples. Glass substrates can also be used for testing to meet actual needs, and this application does not limit it here.

[0113] Optionally, a glass substrate (i.e., a glass matrix sample, one of the matrix samples) is taken for spin coating test. A sample of the recycled PVDF slurry can be spin coated on the silicon-based substrate. After baking and crystallization, a film layer (dry film layer) is formed, and then the optical properties (such as film transmittance and haze) of the film layer can be measured. For example, optionally, the value range of the film transmittance of the film layer can be set to be greater than 95%; optionally, the value range of the haze of the film layer is set to be less than 5%. Of course, these are only examples to meet actual needs, and this application does not limit it here.

[0114] Sub-step S206: If the third predetermined condition is satisfied, the recycled PVDF slurry after filtration treatment is used as the finished PVDF slurry.

[0115] When the third predetermined condition is satisfied, it can be considered that the recycled PVDF slurry after filtration treatment can meet the quality control standard for productization. Therefore, the recycled PVDF slurry after filtration treatment can be used as the finished PVDF slurry. For example, after obtaining the finished PVDF slurry, the finished PVDF slurry can be released and put into use in batches as a product.

[0116] Based on this, through the above quality inspection steps (i.e., sub-steps S202, S204, and S206) in this application, the recycled PVDF slurry can be quality inspected to accurately determine whether the recycled PVDF slurry can be put into use as a finished product, so as to improve the utilization of the recycled PVDF slurry to better meet the needs of recycling.

[0117] Figure 6 The flowchart of another exemplary PVDF slurry recycling method according to the present application is shown. The following refers to Figure 6 For a further exemplary description of the PVDF slurry recycling method in the present application. Figure 6 The shown exemplary PVDF slurry recycling method mainly aims at the solid waste in the first waste. Refer to Figure 6As shown, the PVDF slurry recovery method comprises:

[0118] Step S601: If the target substrate is coated with the first PVDF slurry and N cleaning materials, the first waste outside the target substrate is collected, wherein the cleaning material is used to remove part of the first PVDF slurry on the target substrate during the coating process, the first PVDF slurry includes M solvents, N≥1 and N is an integer, M≥1 and M is an integer, and the first waste is solid waste formed by the solidification of the first PVDF slurry and the cleaning material.

[0119] Optionally, the solid waste is a dry film solid waste, or a block solid waste, which is not limited here. Optionally, the coating can be a spin coating, and the target substrate can be a silicon-based substrate or a glass substrate. The cleaning material can include at least one of an edge washing liquid and a back washing liquid.

[0120] After step S601, the step of preparing the regenerated PVDF slurry is performed, referring to Figure 6 As shown, the preparation steps include three implementation methods: steps S602A to S604A, steps S602B to S604B, and steps S602C to S604C.

[0121] Implementation method 1: Steps S602A to S604A specifically include:

[0122] Step S602A: If the type of at least one of the N cleaning materials is different from the types of the M solvents in the first PVDF slurry, the solid waste is calcined to remove the cleaning material contained in the solid waste to obtain a second waste in powder form.

[0123] Step S603A: Determine the powder parameters of the second waste material in powder form, wherein the powder parameters include at least one of the content of PVDF and its copolymers, Curie temperature, melting point, and melt flow rate of thermoplastics.

[0124] Step S604A: Utilize the second waste material whose powder parameters satisfy the first predetermined condition to perform slurry preparation to obtain regenerated PVDF slurry.

[0125] Implementation method 2: Steps S602B to S604B specifically include:

[0126] Step S602B: If the types of the N cleaning materials are the same as the type of at least one of the M solvents in the first PVDF slurry, the solid waste is dissolved by the solvent of the first PVDF slurry to obtain a second PVDF slurry.

[0127] Step S603B: Determine the viscosity and PVDF solid content of the second PVDF slurry.

[0128] Step S604B: Adjust the viscosity and PVDF solid content of the second PVDF slurry to within a predetermined range to obtain a regenerated PVDF slurry.

[0129] Embodiment 3: Steps S602C to S604C specifically include:

[0130] Step S602C: If the types of all N cleaning materials are the same as at least one of the M solvents in the first PVDF slurry, then perform a calcination treatment on the solid waste to obtain a third waste in powder form.

[0131] Step S603C: Measure the powder parameters of the third waste in powder form, where the powder parameters include at least one of the content of PVDF and its copolymers, Curie temperature, melting point, and melt flow rate of thermoplastics.

[0132] Step S604C: Use the third waste whose powder parameters meet the predetermined conditions for slurry preparation to obtain a regenerated PVDF slurry.

[0133] After the steps for preparing the regenerated PVDF slurry are completed, as shown in Figure 6 perform steps S605 to S607, where:

[0134] Step S605: Filter the regenerated PVDF slurry to remove at least some impurities in the regenerated PVDF slurry.

[0135] Step S606: Perform a quality inspection step on the regenerated PVDF slurry after filtration treatment. The quality inspection step includes: determining whether the viscosity and PVDF solid content of the regenerated PVDF slurry after filtration treatment meet the second predetermined conditions; if they meet the second predetermined conditions, then take samples of the regenerated PVDF slurry after filtration treatment and a substrate sample to perform a coating test on the substrate sample using the sample of the regenerated PVDF slurry, and determine whether the film layer parameters of the film layer formed by the sample of the regenerated PVDF slurry on the substrate sample after the coating test meet the third predetermined conditions, where the film layer parameters include at least one of the thickness of the film layer, thickness uniformity of the film layer, piezoelectric properties of the film layer after polarization, and optical properties of the film layer; if they meet the third predetermined conditions, then use the regenerated PVDF slurry after filtration treatment as the finished PVDF slurry.

[0136] Step S607: Release the finished PVDF slurry as a product in batches for on-line use.

[0137] The above Figure 6Details of each step of the exemplary PVDF slurry recovery method can also be understood by referring to the relevant content in the foregoing. Based on this, the PVDF slurry can be effectively recovered by the above exemplary PVDF slurry recovery method, reducing the waste of PVDF materials, improving the utilization rate of PVDF slurry in the coating process (including but not limited to spin coating process), effectively reducing costs, and being able to more reasonably recover PVDF slurry in the case of mixing PVDF slurry and cleaning materials, improving the effect of recovering PVDF slurry.

[0138] Figure 7 The flowchart of still another exemplary PVDF slurry recovery method according to the present application is shown. The PVDF slurry recovery method in the present application will be further described by way of example with reference to Figure 7 The PVDF slurry recovery method in the present application will be further described by way of example. Figure 7 The exemplary PVDF slurry recovery method shown is mainly directed to the solid waste in the first waste. Referring to Figure 7 As shown, the PVDF slurry recovery method includes:

[0139] Step S701: If the target substrate is coated with the first PVDF slurry and N cleaning materials, collect the first waste outside the target substrate, where the cleaning materials are used to remove part of the first PVDF slurry on the target substrate during the coating process, the first PVDF slurry includes M solvents, N≥1 and N is an integer, M≥1 and M is an integer, and the first waste is a slurry waste formed by mixing the first PVDF slurry and the cleaning materials.

[0140] Optionally, the coating can be spin coating, and the target substrate can be a silicon-based substrate or a glass substrate. The cleaning materials can include at least one of edge washing liquid and back washing liquid.

[0141] Step S702: Filter the slurry waste to remove at least part of the impurities in the slurry waste.

[0142] After step S702, a step of preparing regenerated PVDF slurry is carried out. Referring to Figure 7 As shown, the preparation step includes three implementation manners of steps S703A to S705A, steps S703B to S704B, and steps S703C to S705C. Among them:

[0143] Implementation manner 1: Steps S703A to S705A specifically include:

[0144] Step S703A: If the types of at least one of the N cleaning materials are all different from the types of the M solvents in the first PVDF slurry, calcine the slurry waste to remove the cleaning materials contained in the slurry waste, and obtain a second waste in powder form.

[0145] Step S704A: Measure the powder parameters of the second waste in powder form, where the powder parameters include at least one of the content of PVDF and its copolymers, the Curie temperature, the melting point, and the melt flow rate of the thermoplastic.

[0146] Step S705A: Perform slurry preparation treatment on the second waste whose powder parameters meet the first predetermined condition to obtain a regenerated PVDF slurry.

[0147] Embodiment 2: Steps S703B to S704B specifically include:

[0148] Step S703B: If the types of all N cleaning materials are the same as at least one of the types of M solvents in the first PVDF slurry, measure the viscosity and PVDF solid content of the slurry waste.

[0149] Step S704B: Adjust the viscosity and PVDF solid content of the slurry waste within a predetermined range to obtain a regenerated PVDF slurry.

[0150] Embodiment 3: Steps S703C to S705C specifically include:

[0151] Step S703C: If the types of all N cleaning materials are the same as at least one of the types of M solvents in the first PVDF slurry, perform calcination treatment on the slurry waste to obtain a fourth waste in powder form.

[0152] Step S704C: Measure the powder parameters of the fourth waste in powder form, where the powder parameters include at least one of the content of PVDF and its copolymers, the Curie temperature, the melting point, and the melt flow rate of the thermoplastic.

[0153] Step S705C: Perform slurry preparation treatment on the fourth waste whose powder parameters meet the predetermined condition to obtain a regenerated PVDF slurry.

[0154] After the steps for preparing the regenerated PVDF slurry are completed, refer to Figure 7 as shown, and then perform steps S706 to S708, where:

[0155] Step S706: Filter the regenerated PVDF slurry to remove at least some impurities in the regenerated PVDF slurry.

[0156] Step S707: Conduct a quality inspection step on the regenerated PVDF slurry after filtration treatment. The quality inspection step includes: determining whether the viscosity and PVDF solid content of the regenerated PVDF slurry after filtration treatment meet the second predetermined condition; if they meet the second predetermined condition, take samples of the regenerated PVDF slurry after filtration treatment and matrix samples to perform a coating test on the matrix samples using the samples of the regenerated PVDF slurry, and determine whether the film layer parameters of the film layer formed by the samples of the regenerated PVDF slurry on the matrix samples after the coating test meet the third predetermined condition, where the film layer parameters include at least one of the thickness of the film layer, the thickness uniformity of the film layer, the piezoelectric properties of the film layer after polarization, and the optical properties of the film layer; if they meet the third predetermined condition, use the regenerated PVDF slurry after filtration treatment as the finished PVDF slurry.

[0157] Step S708: Release the finished PVDF slurry as a product in batches for online use.

[0158] The above Figure 7 For the details of each step of the exemplary PVDF slurry recovery method described above, reference can also be made to the relevant content in the previous text. Based on this, the above exemplary PVDF slurry recovery method can effectively recover the PVDF slurry, reduce the waste of PVDF materials, improve the utilization rate of PVDF slurry in the coating process (including but not limited to spin coating process), effectively reduce costs, and can more reasonably recover the PVDF slurry in the case of mixing of PVDF slurry and cleaning materials, improving the effect of recovering the PVDF slurry.

[0159] It can be understood that the above embodiments are only some exemplary embodiments in the embodiments of the present application, and do not impose any limitations on the PVDF slurry recovery solution in the embodiments of the present application.

[0160] As can be seen from the above, in the PVDF slurry recovery solution in the embodiments of the present application, on the one hand, if the target substrate is coated with the first PVDF slurry and N cleaning materials, and the first waste outside the target substrate is collected, and if the types of at least one of the N cleaning materials are all different from the types of M solvents in the first PVDF slurry, the cleaning materials contained in the first waste are removed to obtain the second waste, and the second waste is used for slurry preparation to obtain the recycled PVDF slurry. Therefore, through this PVDF slurry recovery solution, the PVDF slurry can be effectively recovered, reducing the waste of PVDF materials, improving the utilization rate of PVDF slurry in the coating process (including but not limited to spin coating process), and effectively reducing costs; on the other hand, in this recovery solution, if the types of at least one of the N cleaning materials are all different from the types of M solvents in the first PVDF slurry, the cleaning materials contained in the first waste are removed to obtain the second waste, and the second waste is used for slurry preparation to obtain the recycled PVDF slurry. Therefore, through this PVDF slurry recovery solution, the PVDF slurry can be more reasonably recovered when the PVDF slurry and the cleaning materials are mixed, improving the effect of recovering the PVDF slurry.

[0161] Based on the same inventive concept as the foregoing PVDF slurry recovery method, with reference to Figure 8 the block diagram, according to another aspect in the embodiments of the present application, a PVDF slurry recovery system 100 is provided, which includes:

[0162] A collection unit 101, configured to collect the first waste outside the target substrate if the target substrate is coated with the first PVDF slurry and N cleaning materials, where the cleaning materials are used to remove part of the first PVDF slurry on the target substrate during the coating process, the first PVDF slurry includes M solvents, N≥1 and N is an integer, M≥1 and M is an integer;

[0163] A slurry preparation unit 102, configured to, if the types of at least one of the N cleaning materials are all different from the types of M solvents in the first PVDF slurry, remove the cleaning materials contained in the first waste to obtain the second waste, and use the second waste for slurry preparation to obtain the recycled PVDF slurry.

[0164] The PVDF slurry recovery system 100 in the embodiments of the present application corresponds to the respective embodiments of the PVDF slurry recovery method in the foregoing embodiments. The relevant content and beneficial effects of the PVDF slurry recovery system 100 can be understood with reference to the respective embodiments of the above PVDF slurry recovery method, and will not be elaborated herein.

[0165] It should be noted that the term "including" and its variants used in this text are open-ended, that is, "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts such as "first", "second", etc. mentioned in this application are only used to distinguish different devices, modules or units, and are not used to limit the order or mutual dependence of the functions performed by these devices, modules or units.

[0166] It should be noted that the modifications of "one" and "a plurality of" mentioned in this application are illustrative rather than restrictive. Those skilled in the art should understand that unless otherwise clearly specified in the context, it should be understood as "one or more".

[0167] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of this application, and are not intended to limit them; although this application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for recycling PVDF slurry, characterized in that, Including: If the target substrate is coated with the first PVDF slurry and N cleaning materials, the first waste outside the target substrate is collected. Wherein, the cleaning materials are used to remove part of the first PVDF slurry on the target substrate during the coating process. The first PVDF slurry includes M solvents, N≥1 and N is an integer, M≥1 and M is an integer. The first waste includes solid waste formed by solidification of the first PVDF slurry and the cleaning materials, and slurry waste formed by mixing the first PVDF slurry and the cleaning materials. If the types of at least one of the N cleaning materials are all different from the types of the M solvents in the first PVDF slurry, the cleaning materials contained in the first waste are removed to obtain second waste, and the second waste is used for slurry preparation to obtain recycled PVDF slurry. Among them, removing the cleaning materials contained in the first waste to obtain second waste, and using the second waste for slurry preparation to obtain recycled PVDF slurry includes: calcining the first waste to remove the cleaning materials contained in the first waste to obtain second waste in powder form; measuring the powder parameters of the second waste in powder form, and using the second waste whose powder parameters meet the first predetermined conditions for slurry preparation to obtain recycled PVDF slurry.

2. The method according to claim 1, characterized in that, The powder parameters include at least one of the content of PVDF and its copolymers, Curie temperature, melting point, and melt flow rate of thermoplastics.

3. The method according to claim 1, wherein The method further includes: If the types of the N cleaning materials are all the same as the types of at least one of the M solvents in the first PVDF slurry, the first waste is used for slurry preparation to obtain recycled PVDF slurry.

4. The method according to claim 3, characterized in that, For the solid waste in the first waste, Using the first waste for slurry preparation to obtain recycled PVDF slurry includes: Dissolving the solid waste with the solvent of the first PVDF slurry to obtain a second PVDF slurry; Adjusting the viscosity and PVDF solid content of the second PVDF slurry to within a predetermined range to obtain recycled PVDF slurry; Or, Using the first waste for slurry preparation to obtain recycled PVDF slurry includes: Calcining the solid waste to obtain third waste in powder form; Using the third waste for slurry preparation to obtain recycled PVDF slurry.

5. The method according to claim 3, wherein For the slurry waste in the first waste, Using the first waste for slurry preparation to obtain recycled PVDF slurry includes: Adjusting the viscosity and PVDF solid content of the slurry waste to within a predetermined range to obtain recycled PVDF slurry; Or, Using the first waste for slurry preparation to obtain recycled PVDF slurry includes: Calcining the slurry waste to obtain fourth waste in powder form; Using the fourth waste for slurry preparation to obtain recycled PVDF slurry.

6. The method according to claim 1, characterized in that The method further includes: filtering the recycled PVDF slurry to remove at least part of the impurities in the recycled PVDF slurry.

7. The method according to claim 6, characterized in that, The method further includes: determining whether the viscosity and PVDF solid content of the recycled PVDF slurry after the filtering treatment meet a second predetermined condition; if the second predetermined condition is met, taking a sample of the recycled PVDF slurry after the filtering treatment and a substrate sample, and performing a coating test on the substrate sample using the sample of the recycled PVDF slurry to determine whether the film layer parameters of the film layer formed by the sample of the recycled PVDF slurry on the substrate sample after the coating test meet a third predetermined condition, where the film layer parameters include at least one of the thickness of the film layer, the thickness uniformity of the film layer, the piezoelectric properties of the film layer after polarization, and the optical properties of the film layer; if the third predetermined condition is met, using the recycled PVDF slurry after the filtering treatment as the finished PVDF slurry.

8. The method according to claim 1, wherein The cleaning material includes at least one of an edge washing liquid and a back washing liquid.

9. A recovery system for PVDF slurry, characterized in that, It includes: a collecting unit, configured to collect a first waste outside the target substrate if the target substrate is coated with a first PVDF slurry and N types of cleaning materials, where the cleaning materials are used to remove part of the first PVDF slurry on the target substrate during the coating process, the first PVDF slurry includes M solvents, N≥1 and N is an integer, M≥1 and M is an integer, the first waste includes a solid waste formed by solidification of the first PVDF slurry and the cleaning materials, and a slurry waste formed by mixing the first PVDF slurry and the cleaning materials; a slurry preparation unit, configured to, if the types of at least one of the N types of cleaning materials are all different from the types of the M solvents in the first PVDF slurry, remove the cleaning materials included in the first waste to obtain a second waste, and perform a slurry preparation process on the second waste to obtain a recycled PVDF slurry; wherein, the slurry preparation unit is specifically configured to perform a calcination treatment on the first waste to remove the cleaning materials included in the first waste to obtain a second waste in powder form; determine the powder parameters of the second waste in powder form, and perform a slurry preparation process on the second waste whose powder parameters meet a first predetermined condition to obtain a recycled PVDF slurry.

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