Reutilization method of photosensitive polyimide waste
By inducing the polymerization reaction between photosensitive polyimide waste and crosslinking agent with ultraviolet light, combined with thermal imidization treatment, the problems of difficult degradation and recycling of photosensitive polyimide waste have been solved, and efficient and environmentally friendly recycled product preparation has been achieved.
Patent Information
- Application Number
- CN202410538537.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-30
- Publication Date
- 2025-10-31
AI Technical Summary
In existing technologies, the treatment of photosensitive polyimide waste involves high costs, energy consumption, and environmental pollution. Furthermore, chemical degradation and recycling can easily damage the molecular structure, making it difficult to achieve efficient recycling.
By mixing photosensitive polyimide waste with photoinitiators, crosslinking agents, and solvents, molding and processing it under ultraviolet light, and then performing thermal imidization treatment, a recycled product is formed, thus realizing the direct recycling of photosensitive polyimide waste.
It achieves 100% recycling of photosensitive polyimide waste, maintaining its physical and molecular structure, reducing recycling costs, and minimizing performance loss in recycled products.
Smart Images
Figure CN120865484A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of material recycling technology, specifically to a method for reusing photosensitive polyimide waste. Background Technology
[0002] Polyimide, due to its excellent mechanical properties, high heat resistance, and thermal stability, is widely used in the preparation of thin films, photoresists, foams, and other materials for numerous applications. Photosensitive polyimide is an essential key material for advanced packaging; however, it requires very high standards regarding its molecular weight, molecular weight distribution, quality stability, and storage stability after being formulated as a photoresist. If the quality does not meet the requirements or the storage period is exceeded, it can no longer be used as a photoresist. Therefore, the disposal of substandard resins or photoresists has become a problem in the industry.
[0003] The main treatment methods at present are (1) high-temperature combustion as solid waste, which is not only costly but also energy-consuming; (2) solid landfill, but polyimide is highly stable and difficult to degrade, which can easily cause environmental pollution; (3) chemical degradation and recycling, but the technology is not mature at present, and it will also cause new environmental pollution. Summary of the Invention
[0004] The purpose of this application is to provide a method for the direct recycling of photosensitive polyimide waste, which can effectively solve the problems existing in the current physical and chemical methods for polyimide recycling.
[0005] To achieve the above objectives, the technical solution of this application provides a method for recycling photosensitive polyimide waste, comprising: mixing photosensitive polyimide waste or photosensitive polyimide prepolymer obtained by processing the photosensitive polyimide waste, a photoinitiator, a crosslinking agent, and a solvent to form a mixture; molding the mixture under ultraviolet light irradiation to obtain a recycled product; and subjecting the recycled product to thermal imidization treatment.
[0006] In some embodiments of this application, the photosensitive polyimide waste is photosensitive polyimide that was not used after synthesis due to non-compliance with requirements or photoresist waste generated from the photolithography process; the method for processing the photosensitive polyimide waste to obtain photosensitive polyimide prepolymer includes: adding a mixed solvent of water and methanol to the photoresist waste to obtain a precipitate, washing and drying the precipitate to obtain the photosensitive polyimide prepolymer.
[0007] In some embodiments of this application, the mass ratio of the photosensitive polyimide prepolymer, photoinitiator, crosslinking agent and solvent is (5-12):(0.1-1):(0.1-1):(8-15).
[0008] In some embodiments of this application, the photoinitiator includes at least one of diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]acetone-1-(O-acetyloxime).
[0009] In some embodiments of this application, the crosslinking agent includes at least one of triethylene glycol diacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol diacrylate, polyethylene glycol diacrylate, and polyethylene glycol diacrylate.
[0010] In some embodiments of this application, the solvent includes at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, N-vinylpyrrolidone, tetrahydrofuran, N,N-dimethylacrylamide, and lauric acid.
[0011] In some embodiments of this application, the molding process is one of casting, layer-by-layer molding, and additive manufacturing; the wavelength of the ultraviolet light is 365nm or 405nm.
[0012] In some embodiments of this application, the thermal imidization treatment of the recycled product includes: programmatically heating the recycled product from 50°C to 280°C.
[0013] In some embodiments of this application, the method of programmatically raising the temperature of the recycled product from 50°C to 280°C includes, in sequence: holding at 50°C for 1 hour, raising the temperature to 100°C and holding for 1 hour, raising the temperature to 150°C and holding for 2 hours, raising the temperature to 200°C and holding for 2 hours, and raising the temperature to 280°C and holding for 4 hours.
[0014] In some embodiments of this application, the photosensitive polyimide in the photosensitive polyimide waste is formed by the condensation of dianhydride and diamine substances linked by ester bonds to form photosensitive groups, wherein: the dianhydride / the combination of the dianhydride substances is selected from at least one of 4,4'-oxobisphthalic anhydride / 4,4'-diaminodiphenyl ether, hexafluorodianhydride-4,4' / diaminodiphenyl ether, hexafluorodianhydride / 1,3-bis(3-aminophenoxy)benzene, hexafluorodianhydride / 9,9-bis(4-aminophenyl)fluorene, 3,3',4,4'-biphenyltetracarboxylic dianhydride / 2,2-bis(trifluoromethyl)-4,4'-diaminophenyl ether; the compound providing the photosensitive group is selected from at least one of 2-hydroxyethyl methacrylate, hydroxyethyl acrylate, methacrylate (2-(dimethylamino)ethyl methacrylate).
[0015] Compared with existing technologies, the recycling method for photosensitive polyimide waste in this application has the following advantages:
[0016] By employing ultraviolet light to induce a polymerization reaction between photosensitive polyimide waste and a crosslinking agent, including additive manufacturing methods such as photopolymerization printing and digital light projection printing, recycled products can be obtained simultaneously. This achieves the direct recycling of photosensitive polyimide waste with a recycling rate of up to 100%. Furthermore, the entire recycling process does not damage the physical or molecular structure of the photosensitive polyimide. Therefore, the recycled products have lower performance loss compared to the virgin materials, effectively solving the problems of difficult degradation, difficult recycling, and high recycling costs associated with photosensitive polyimide waste. Attached Figure Description
[0017] The following accompanying drawings describe in detail the exemplary embodiments disclosed in this application. The same reference numerals denote similar structures in several views of the drawings. Those skilled in the art will understand that these embodiments are non-limiting and exemplary, and the drawings are for illustrative purposes only and are not intended to limit the scope of this application. Other embodiments may similarly fulfill the inventive intent of this application. It should be understood that the drawings are not drawn to scale. Wherein:
[0018] Figure 1 This is a schematic flowchart of a method for recycling photosensitive polyimide waste according to an embodiment of this application.
[0019] Figure 2 The image shows the ultraviolet spectrum of the mixture in Example 1 of this application;
[0020] Figure 3 The DSC curves are shown for the recycled product after heat imidization in Example 1 and Example 2 of this application.
[0021] Figure 4 This is a black and white photograph of the recycled product obtained after thermal imidization treatment in Example 2 of this application;
[0022] Figure 5 The infrared spectra of the directly recycled photosensitive polyimide waste and the recycled product after thermal imidization in Example 2 of this application are shown.
[0023] Figure 6 The infrared spectra of the un-thermally imidized recycled product and the thermally imidized recycled product in Example 4 of this application are shown.
[0024] Figure 7 This is a stress-strain curve diagram of the recycled product without thermal imidization and the recycled product after thermal imidization in Example 4 of this application;
[0025] Figure 8This is a graph showing the variation of the storage modulus and loss modulus of the regenerated product after thermal imidization in Example 4 of this application as a function of temperature.
[0026] Figure 9 This is a graph showing the trend of the loss tangent of the regenerated products after thermal imidization as a function of temperature in Examples 4, 5 and 6 of this application;
[0027] Figure 10 Thermogravimetric curves of the regenerated products after thermal imidization in Examples 4, 5 and 6 of this application are shown. Detailed Implementation
[0028] The following description provides specific application scenarios and requirements for this application, intended to enable those skilled in the art to make and use the content of this application. Various partial modifications to the disclosed embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments and applications without departing from the spirit and scope of this application. Therefore, this application is not limited to the embodiments shown, but rather to the widest scope consistent with the claims.
[0029] Currently, physical methods for recycling polyimide waste require the development of customized equipment for mixing, crushing, granulation, and melting-remolding, resulting in complex processes and a lack of universal applicability. Chemical methods, on the other hand, require disrupting the existing molecular backbone structure of polyimide, consuming large amounts of chemical reagents, lacking atom economy, and subjecting the hydrolysis process to harsh conditions, typically requiring high temperatures and strong acids or alkalis as auxiliaries, while making it difficult to obtain pure dianhydrides or diamines. Furthermore, both physical and chemical methods cause physical or molecular-level damage to polyimide, severely impacting the properties of the recycled material.
[0030] Based on this, the technical solution of this application recycles photosensitive polyimide by means of in-situ reuse, so it will not damage the physical or molecular structure of photosensitive polyimide. During molding and processing, ultraviolet light curing is used to induce the polymerization reaction between the waste photosensitive polyimide and the crosslinking agent, achieving high atom economy. At the same time, the molded device has both heat resistance and mechanical properties. Moreover, the entire recycling process does not involve expensive reagents, consumables and equipment, etc., reducing the cost of recycling and solving the recycling problem of photosensitive polyimide from a fundamental perspective.
[0031] refer to Figure 1 In some embodiments of this application, the method for recycling the photosensitive polyimide waste includes the following steps:
[0032] S1: Mix photosensitive polyimide waste or photosensitive polyimide prepolymer obtained by processing the photosensitive polyimide waste, photoinitiator, crosslinking agent and solvent to form a mixture;
[0033] S2: Under ultraviolet light irradiation, the mixture is molded to obtain a recycled product;
[0034] S3: Perform thermal imidization treatment on the recycled product.
[0035] In step S1, the photosensitive polyimide waste includes photosensitive polyimide. In some embodiments, the photosensitive polyimide is formed by the condensation polymer of a dianhydride and a diamine through ester bonds connecting photosensitive groups.
[0036] In some embodiments, the dianhydride substance / combination of the dianhydride substances is selected from at least one of 4,4'-oxophthalic anhydride / 4,4'-diaminodiphenyl ether (ODPA / ODA), hexafluorodianhydride-4,4' / diaminodiphenyl ether (6FDA / ODA), hexafluorodianhydride / 1,3-bis(3-aminophenoxy)benzene (6FDA / APB), hexafluorodianhydride / 9,9-bis(4-aminophenyl)fluorene (6FDA / FDA), and 3,3',4,4'-biphenyltetracarboxylic dianhydride / 2,2-bis(trifluoromethyl)-4,4'-diaminophenyl ether (BPDA / 6FODA). In some embodiments, the compound providing the photosensitive group is selected from at least one of 2-hydroxyethyl methacrylate (HEMA), hydroxyethyl acrylate, and methacrylate (2-(dimethylamino)ethyl methacrylate).
[0037] In this application, the combination of dianhydride, diamine, and a compound providing a photosensitive group used to synthesize photosensitive polyimide is referred to as the synthesis system of photosensitive polyimide. Preferably, the synthesis system of photosensitive polyimide is ODPA / ODA / HEMA or 6FDA / APB / HEMA.
[0038] Besides photosensitive polyimide, the photosensitive polyimide waste also contains other substances. For example, when the photosensitive polyimide waste is photoresist waste generated from the photolithography process, it will also contain solvents, photoinitiators, developers, and fixers, etc. The photosensitive polyimide waste can also be photosensitive polyimide that was synthesized but not used due to non-compliance. In some embodiments, to prevent large volume shrinkage of the recycled product due to the volatilization of volatile substances during subsequent thermal imidization, and to increase the solid content of the photosensitive polyimide, thereby improving the performance of the recycled product, the photosensitive polyimide waste is treated to obtain a photosensitive polyimide prepolymer. The treatment method may include: adding a mixed solvent of water and methanol to the photoresist waste to obtain a precipitate, washing and drying the precipitate to obtain the photosensitive polyimide prepolymer. In the mixed solvent, the volume ratio of water to methanol can be (1-5):1.
[0039] In some embodiments, in step S1, the photoinitiator includes at least one of diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (photoinitiator 819), ethyl 2,4,6-trimethylbenzoylphenylphosphonate (TPO-L), and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]acetone-1-(O-acetyl oxime) (OEX-2).
[0040] In some embodiments, in step S1, the crosslinking agent includes at least one of triethylene glycol diacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol diacrylate (number average molecular weight, for example, 400), polyethylene glycol diacrylate (number average molecular weight, for example, 1000), and polyethylene glycol diacrylate (number average molecular weight, for example, 1600).
[0041] In some embodiments, in step S1, the solvent includes at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, N-vinylpyrrolidone, tetrahydrofuran, N,N-dimethylacrylamide, and lauric acid.
[0042] In some embodiments, in step S1, a spin coater is used to mix the photosensitive polyimide prepolymer, the photoinitiator, the crosslinking agent and the solvent evenly, and the spin coater can rotate at a speed of 1000 rpm to 1500 rpm.
[0043] In the mixture, the mass ratio of the photosensitive polyimide prepolymer, photoinitiator, crosslinking agent and solvent is (5-12):(0.1-1):(0.1-1):(8-15). The recycled product obtained within this mass ratio range has good optical, thermal and mechanical properties.
[0044] In step S2, the forming process is, for example, one of casting, layer-by-layer molding, or additive manufacturing. The casting method may include: pouring the mixture into a mold and irradiating it with ultraviolet light of 365nm or 405nm wavelength for 5 to 10 minutes to obtain the target device.
[0045] The layer-by-layer molding method may include: pouring an appropriate amount of the mixture into a customized mold, with a pouring thickness of, for example, 1 mm to 3 mm; irradiating the mixture with ultraviolet light of wavelength 365 nm or 405 nm for 5 to 10 seconds to rapidly transform the mixture into a solid state, forming the first layer structure; then continuing to pour an appropriate amount of the mixture and solidifying it under the same conditions to form the second layer structure; and so on, layer by layer molding to obtain the final structural device.
[0046] The additive manufacturing method may include: fabricating shaped devices from the mixture using 3D printing technologies based on ultraviolet-induced free radical photopolymerization, such as stereolithography (SLA), ultraviolet-direct ink writing (UV-DIW), and digital light processing (DLP), wherein the wavelength of the ultraviolet light is 365nm or 405nm. Preferably, using ultraviolet light with a wavelength of 405nm allows for better matching with oxime ester photoinitiators.
[0047] In step S3, the thermal imidization treatment of the recycled product includes: programmatically heating the recycled product from 50°C to 280°C. Specifically, the recycled product can be placed in a high-temperature oven for programmatic heating. In some preferred embodiments, the method of programmatically heating the recycled product from 50°C to 280°C sequentially includes: holding at 50°C for 1 hour (50°C / 1h), heating to 100°C and holding for 1 hour (100°C / 1h), heating to 150°C and holding for 2 hours (150°C / 2h), heating to 200°C and holding for 2 hours (200°C / 2h), and heating to 280°C and holding for 4 hours (280°C / 4h). This heating method can better promote imidization and convert photosensitive polyamide ester into polyimide.
[0048] Example
[0049] The technical solution of this application will be clearly and completely described below with reference to the embodiments of this application. Unless otherwise specified, the reagents and raw materials used can be purchased commercially. Experimental methods in the following embodiments that do not specify specific conditions are performed according to conventional methods and conditions, or according to the product instructions.
[0050] Example 1
[0051] The photosensitive polyimide waste in this embodiment is photoresist waste generated during the photolithography process, and this photoresist waste includes 40g of photosensitive polyimide with a synthesis system of ODPA / ODA / HEMA, 3g of cyclopentanone, and 2.5g of propylene glycol methyl ether acetate. The method for reusing the photosensitive polyimide waste in this embodiment includes the following steps:
[0052] (1) Photosensitive polyimide waste was treated with a mixed solvent of water and methanol with a volume ratio of 2:1 to obtain precipitates. The precipitates were washed and dried to obtain 30g of photosensitive polyimide prepolymer.
[0053] (2) Mix 30g of photosensitive polyimide prepolymer, 2.5g of phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, 5g of tetraethylene glycol dimethacrylate and 62.5g of N,N-dimethylformamide evenly to form a mixture.
[0054] (3) Pour the mixture into a mold and irradiate it with ultraviolet light of 405nm wavelength for 45s to obtain the recycled product;
[0055] (4) The recycled product is placed in a high-temperature oven for thermal imidization treatment, and the heating program is 50℃ / 1h, 100℃ / 1h, 150℃ / 2h, 200℃ / 2h and 280℃ / 4h.
[0056] The optical properties of the mixture were tested: the mixture was diluted 1000 times and tested using a UV spectrophotometer (Shimadzu UV-2600, Japan), with a wavelength range of 200 nm to 800 nm. The obtained UV spectrum is shown below. Figure 2 As shown.
[0057] Differential scanning calorimetry (DSC) was performed on the regenerated product after heat imidization: using a TA Instruments Discovery DSC 250, the temperature was increased to 300°C at a flow rate of 10°C / min in atmospheric air at a flow rate of 40 mL / min, and the test was conducted using an RCS mechanical refrigeration system. The obtained DSC curves are shown below. Figure 3The a-curve is shown in the figure. Since the solvent N,N-dimethylformamide did not participate in the crosslinking reaction during the UV curing process, it evaporated and overflowed during the subsequent thermal imidization treatment, leaving only polyimide in the system. Therefore, a high Tg peak (256℃) appears in the a-curve.
[0058] Example 2
[0059] The photosensitive polyimide waste in this embodiment is photoresist waste generated during the photolithography process, and this photoresist waste includes 30g of photosensitive polyimide with a synthesis system of ODPA / ODA / HEMA, 3g of cyclopentanone, and 2.5g of propylene glycol methyl ether acetate. The method for reusing the photosensitive polyimide waste in this embodiment includes the following steps:
[0060] (1) The directly recycled photosensitive polyimide waste, 2.5g of diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxychloride, 2.5g of polyethylene glycol diacrylate (Mn=400) and 59.5g of N,N-dimethylacrylamide are mixed evenly to form a mixture.
[0061] (2) The mixture was 3D printed using a digital light processing method based on ultraviolet light-induced free radical photopolymerization at a wavelength of 405nm to obtain recycled products;
[0062] (3) The recycled product was placed in a high-temperature oven for thermal imidization treatment, and the heating program was 50℃ / 1h, 100℃ / 1h, 150℃ / 2h, 200℃ / 2h and 280℃ / 4h to obtain the recycled product 6FDA-ODA-30.
[0063] Figure 4 This is a photograph of the recycled product obtained after the thermal imidization treatment in this embodiment.
[0064] Fourier transform infrared spectroscopy (NIRS) was used to detect the direct recycling of photosensitive polyimide waste and 6FDA-ODA-30 using a Niclait 6700 micrometer (Platinum Elmer, USA) to monitor the C=C bond transition over time. The wavenumber range was 4000. -1 ~650cm -1 The test results are as follows Figure 5 As shown. Reference Figure 5 Curve a is the infrared spectrum of 6FDA-ODA-30, and curve b is the infrared spectrum of directly recycled photosensitive polyimide waste. The absorption peak of the C=C bond in curve a (1620 cm⁻¹) can be observed. -1 The absorption peak of the C=O bond (1725 cm⁻¹) has disappeared. -1 The radical-induced double bond polymerization reaction still exists, and a significant increase in the conversion rate of C=C bonds was observed in a short period of time, indicating the rapid nature of the free radical-initiated double bond polymerization reaction.
[0065] The DSC curve of 6FDA-ODA-30 in this embodiment is as follows: Figure 3 As shown in curve b, because the solvent N,N-dimethylacrylamide participates in the crosslinking reaction during the photocuring process and in a very high proportion, the system will be dominated by the properties of poly N,N-dimethylacrylamide, and will show a Tg peak of 140℃ in the DSC curve.
[0066] Example 3
[0067] The photosensitive polyimide waste in this embodiment is a waste product synthesized through photolithography but whose performance does not meet the requirements of the photolithography process; therefore, it is directly recycled and reused. Its chemical structure is ODPA / ODA / HEMA photosensitive polyimide. The reuse method of the photosensitive polyimide waste in this embodiment includes the following steps:
[0068] (1) Mix 30g of directly recycled photosensitive polyimide waste, 2.5g of propylene glycol methyl ether acetate, 2.5g of diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxychloride, 2.5g of polyethylene glycol diacrylate (Mn=400) and 59.5g of N-vinylpyrrolidone evenly to form a mixture.
[0069] (2) The mixture is molded layer by layer to obtain the recycled product. Each layer is irradiated with ultraviolet light at a wavelength of 405nm for 10s.
[0070] (3) The recycled product was placed in a high-temperature oven for thermal imidization treatment, and the heating program was 50℃ / 1h, 100℃ / 1h, 150℃ / 2h, 200℃ / 2h and 280℃ / 4h to obtain the recycled product ODPA-ODA-30-NVP.
[0071] Example 4
[0072] The photosensitive polyimide waste in this embodiment is photoresist waste generated during the photolithography process, and this photoresist waste includes 40g of photosensitive polyimide with a synthesis system of 6FDA / APB / HEMA, 2.5g of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 5g of cyclopentanone, and 2.5g of propylene glycol methyl ether acetate. The method for reusing the photosensitive polyimide waste in this embodiment includes the following steps:
[0073] (1) Photosensitive polyimide waste was treated with a mixed solvent of water and methanol in a volume ratio of 1:1 to obtain precipitates. The precipitates were washed and dried to obtain 30g of photosensitive polyimide prepolymer.
[0074] (2) Mix 30g of photosensitive polyimide prepolymer, 2.5g of phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, 2.5g of tetraethylene glycol dimethacrylate, 2.5g of polyethylene glycol diacrylate (Mn=1000) and 62.5g of N-dimethylacrylamide evenly to form a mixture.
[0075] (3) The mixture is 3D printed using digital light processing based on ultraviolet light-induced free radical photopolymerization at a wavelength of 405nm to obtain recycled products;
[0076] (4) The recycled product was placed in a high-temperature oven for thermal imidization treatment, and the heating program was 50℃ / 1h, 100℃ / 1h, 150℃ / 2h, 200℃ / 2h and 280℃ / 4h to obtain the recycled product 6FDA-APB-30.
[0077] The unheat-imide-treated recycled product and the heat-imide-treated 6FDA-APB-30 were detected by Fourier transform infrared spectroscopy (NIKKLE 6700, Platinum Elmer, USA), with a scan wavenumber range of 4000. -1 ~650cm -1 The test results are as follows Figure 6 As shown. In Figure 6 In the diagram, curve a represents the infrared spectrum of the recycled product before thermal imidization, and curve b represents the infrared spectrum of 6FDA-APB-30. Both the recycled products before and after thermal imidization exhibit symmetric and asymmetric C=O stretching vibrations of imide (1717 cm⁻¹). -1 Without thermal imidization, the recycled product contains a CO-NH structure, which is present at 1640 cm⁻¹. -1 NH vibrations occur nearby, at 1610 cm⁻¹ -1 CN vibrations are generated nearby. After thermal imidization, a stable five-membered ring structure is formed, 1610 cm⁻¹. -1 1640cm -1 The nearby absorption peak disappears, and the stretching vibration peak of the CNC bond (1375 cm⁻¹) appears. -1 Significantly enhanced.
[0078] Mechanical properties of unheat-imidized recycled products and 6FDA-APB-30 were tested using a universal tensile testing machine (SUST, Zhuhai). The tensile specimens were 75 mm in diameter, dumbbell-shaped, and the tensile rate was 5 mm / min. Test results are shown in Table 1 and... Figure 7 As shown.
[0079] Table 1. Mechanical property test results of Example 4
[0080]
[0081]
[0082] 6FDA-APB-30 was tested using a dynamic thermomechanical analyzer (TA Instruments, Q800 series, USA), heated to 320°C at a rate of 5°C / min, at a frequency of 1Hz. The test results are as follows: Figure 8 and Figure 9 As shown, Figure 8 The α curve shows the trend of energy storage modulus with temperature change. Figure 8 The b-curve shows the trend of loss modulus changing with temperature. Figure 9 The curve a shows the trend of the loss tangent Tanδ as a function of temperature.
[0083] Example 5
[0084] The photosensitive polyimide waste in this embodiment is photoresist waste generated during the photolithography process, and this photoresist waste includes 50g of photosensitive polyimide with a synthesis system of 6FDA / APB / HEMA, 3g of cyclopentanone, and 2.5g of propylene glycol methyl ether acetate. The method for reusing the photosensitive polyimide waste in this embodiment includes the following steps:
[0085] (1) Photosensitive polyimide waste was treated with a mixed solvent of water and methanol in a volume ratio of 1:1 to obtain 40g of photosensitive polyimide prepolymer;
[0086] (2) Mix 40g of photosensitive polyimide prepolymer, 2.5g of phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, 2.5g of tetraethylene glycol dimethacrylate, 2.5g of polyethylene glycol diacrylate (Mn=1000), and 52.5g of N-dimethylacrylamide evenly to form a mixture.
[0087] (3) The mixture is 3D printed using digital light processing based on ultraviolet light-induced free radical photopolymerization at a wavelength of 405nm to obtain recycled products;
[0088] (4) The recycled product was placed in a high-temperature oven for thermal imidization treatment, and the heating program was 50℃ / 1h, 100℃ / 1h, 150℃ / 2h, 200℃ / 2h and 280℃ / 4h to obtain the recycled product 6FDA-APB-40.
[0089] 6FDA-APB-40 was tested using a dynamic thermomechanical analyzer (TA Instruments, Q800 series, USA), heated to 320°C at a rate of 5°C / min, at a frequency of 1Hz. Test results... Figure 9 As shown by curve b.
[0090] Example 6
[0091] The photosensitive polyimide waste in this embodiment is photoresist waste generated during the photolithography process, and this photoresist waste includes 75g of photosensitive polyimide with a synthesis system of 6FDA / APB / HEMA, 3g of cyclopentanone, and 2.5g of propylene glycol methyl ether acetate. The method for reusing the photosensitive polyimide waste in this embodiment includes the following steps:
[0092] (1) Photosensitive polyimide waste was treated with a mixed solvent of water and methanol in a volume ratio of 1:1 to obtain 50g of photosensitive polyimide prepolymer;
[0093] (2) Mix 50g of photosensitive polyimide prepolymer, 2.5g of phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, 2.5g of tetraethylene glycol dimethacrylate, 2.5g of polyethylene glycol diacrylate (Mn=1000) and 42.5g of N-dimethylformamide evenly to form a mixture.
[0094] (3) The mixture is 3D printed using digital light processing based on ultraviolet light-induced free radical photopolymerization at a wavelength of 405nm to obtain recycled products;
[0095] (4) The recycled product was placed in a high-temperature oven for thermal imidization treatment, and the heating program was 50℃ / 1h, 100℃ / 1h, 150℃ / 2h, 200℃ / 2h and 280℃ / 4h to obtain the recycled product 6FDA-APB-50.
[0096] 6FDA-APB-50 was tested using a dynamic thermomechanical analyzer (TA Instruments, Q800 series, USA), heated to 320°C at a rate of 5°C / min, at a frequency of 1Hz. Test results... Figure 9 The c-curve is shown.
[0097] The regenerated products from Examples 2–6 after thermal imidization were tested using a thermogravimetric analyzer (TA Instruments, Discovery 550, USA). The temperature was increased to 800°C at a rate of 20°C / min in a nitrogen atmosphere. The test results are shown in Table 2 and [Table data would be inserted here]. Figure 10 As shown.
[0098] Table 2. Thermogravimetric test results of Examples 2-6
[0099]
[0100] Comparative Example
[0101] Preparation of primary materials
[0102] 25.9009 g (4.6532 mol) of DMAc and 3.9823 g (0.0306 mol) of HEMA were added to a three-necked flask. Stirring was started, and 4.6532 g (0.015 mol) of ODPA was added in batches during heating. The mixture was stirred for 1 hour under a nitrogen atmosphere. After the nitrogen atmosphere was closed, the reaction continued for 12 hours under a nitrogen atmosphere to obtain ODPA-HEMA. The mixture was then cooled to room temperature. 4.4614 g (0.0375 mol) of thionyl chloride was added dropwise to a three-necked flask wrapped in an ice-water bath using a constant-pressure funnel. The reaction continued for 4 hours at room temperature to prepare ODPA-HEMA-Cl. 3.0357 g (0.03 mol) of triethylamine and 3.0786 g (0.0154 mol) of ODA were added to a washed and dried 2 L three-necked flask. Under ice-water bath conditions, ODPA-HEMA-Cl was added dropwise to a three-necked flask, and the reaction was continued for 6 hours under nitrogen protection to obtain ODPA-ODA-HEMA polyamide ester (PSPAE).
[0103] Dynamic thermomechanical analysis and thermogravimetric analysis were performed on the ODPA-ODA-HEMA polyamide ester prepared in the comparative example, and the test methods were the same as in Example 6. The results showed that the Tg of the newly prepared virgin material was 213℃, Td5 was 365℃, and Td10 was 389℃.
[0104] In summary, the recycled devices manufactured using the recycling method of photosensitive polyimide waste according to the embodiments of this application still possess better heat resistance and mechanical properties compared to virgin materials.
[0105] The above description of the embodiments is intended to enable those skilled in the art to understand and apply this application. It will be apparent to those skilled in the art that various modifications can be easily made to these embodiments, and the general principles described herein can be applied to other embodiments without creative effort. Therefore, this application is not limited to the embodiments described herein, and any improvements and modifications made by those skilled in the art based on the disclosure of this application without departing from the scope and spirit of this application are within the scope of this application.
Claims
1. A method for recycling photosensitive polyimide waste, characterized in that, include: A mixture is formed by mixing photosensitive polyimide waste or photosensitive polyimide prepolymer obtained by processing the photosensitive polyimide waste, a photoinitiator, a crosslinking agent, and a solvent. The mixture is shaped and processed under ultraviolet light to obtain a recycled product; The recycled product is subjected to thermal imidization treatment.
2. The method for recycling photosensitive polyimide waste according to claim 1, characterized in that, The photosensitive polyimide waste refers to photosensitive polyimide that was not used after synthesis due to non-compliance with requirements or photoresist waste generated from the photolithography process. The method for processing the photosensitive polyimide waste to obtain photosensitive polyimide prepolymer includes: adding a mixed solvent of water and methanol to the photoresist waste to obtain a precipitate, washing and drying the precipitate to obtain the photosensitive polyimide prepolymer.
3. The method for recycling photosensitive polyimide waste according to claim 1 or 2, characterized in that, The mass ratio of the photosensitive polyimide prepolymer, photoinitiator, crosslinking agent and solvent is (5-12):(0.1-1):(0.1-1):(8-15).
4. The method for recycling photosensitive polyimide waste according to claim 1 or 2, characterized in that, The photoinitiator includes at least one of diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]acetone-1-(O-acetyloxime).
5. The method for recycling photosensitive polyimide waste according to claim 1 or 2, characterized in that, The crosslinking agent includes at least one of triethylene glycol diacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol diacrylate, polyethylene glycol diacrylate, and polyethylene glycol diacrylate.
6. The method for recycling photosensitive polyimide waste according to claim 1 or 2, characterized in that, The solvent includes at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, N-vinylpyrrolidone, tetrahydrofuran, N,N-dimethylacrylamide, and lauric acid.
7. The method for recycling photosensitive polyimide waste according to claim 1 or 2, characterized in that, The forming process is one of casting, layer-by-layer molding, and additive manufacturing; the wavelength of the ultraviolet light is 365nm or 405nm.
8. The method for recycling photosensitive polyimide waste according to claim 1 or 2, characterized in that, The thermal imidization treatment of the recycled product includes: gradually increasing the temperature of the recycled product from 50°C to 280°C.
9. The method for recycling photosensitive polyimide waste according to claim 8, characterized in that, The method for programmatically heating the recycled product from 50°C to 280°C includes the following steps: holding at 50°C for 1 hour, heating to 100°C and holding for 1 hour, heating to 150°C and holding for 2 hours, heating to 200°C and holding for 2 hours, and heating to 280°C and holding for 4 hours.
10. The method for recycling photosensitive polyimide waste according to claim 1 or 2, characterized in that, The photosensitive polyimide in the waste material is a condensation polymer of dianhydride and diamine, formed by photosensitive groups linked by ester bonds, wherein: The combination of the dianhydride / diamine is selected from at least one of 4,4'-oxobisphthalic anhydride / 4,4'-diaminodiphenyl ether, hexafluorodianhydride-4,4' / diaminodiphenyl ether, hexafluorodianhydride / 1,3-bis(3-aminophenoxy)benzene, hexafluorodianhydride / 9,9-bis(4-aminophenyl)fluorene, and 3,3',4,4'-biphenyltetracarboxylic dianhydride / 2,2-bis(trifluoromethyl)-4,4'-diaminophenyl ether; the compound providing the photosensitive group is selected from at least one of 2-hydroxyethyl methacrylate, hydroxyethyl acrylate, and 2-(dimethylamino)ethyl methacrylate.