High-efficiency thermal stripping method for waste nickel mesh surface photosensitive adhesive

Abstract

The application discloses a high-efficiency thermal stripping method for waste nickel mesh surface photosensitive glue, places the nickel mesh in an atmosphere furnace after gas condensation transformation, controls the gas atmosphere in the furnace to be nitrogen and air in sequence, and controls the temperature to be 200-600 o Under the constant temperature condition, the photosensitive glue is condensed into photosensitive glue recycling material after thermal stripping for 0.5-5h and 0.5-1h, and the nickel mesh can be directly used as a nickel resource after degumming. No waste water and harmful waste gas are generated in the treatment process, and the method is a high-efficiency treatment method.

Description

Technical Field

[0001] This invention relates to an efficient thermal stripping method for photosensitive adhesive on the surface of waste nickel mesh, belonging to the field of metallurgy and waste resource recycling technology. Background Technology

[0002] The reuse of waste nickel mesh (as a metallurgical raw material or for reuse in the textile printing and dyeing industry) requires the removal of the photosensitive adhesive and the dye curing film layer adhering to its surface, that is, the curing film layer needs to be removed (which can be simply referred to as film removal).

[0003] Existing methods for removing the film from waste nickel mesh involve immersing and dissolving it in a film-removing agent solution of a certain temperature and concentration, or immersing and dissolving it in the film-removing agent solution and enhancing the removal effect with the ultrasonic cavitation effect (CN109626448B). A domestically invented technology is the physicochemical swelling removal method. This method involves immersing the nickel mesh in a film-removing solution at a specific temperature. The functional compound rapidly wets the surface of the nickel mesh through molecular thermal motion and diffuses and penetrates the surface of the cured film. A regular, oriented adsorption layer is formed at corresponding micropores or defects on the inner and outer surfaces of the cured film. Various intermolecular forces exert a traction and stretching effect on the surface of the cured film, opposite to the adhesion force. The photosensitive cured film rapidly swells and quickly peels off its bonded surface. Another existing method for pre-treating non-ferrous metal metallurgical raw materials uses combustion to remove combustible volatile impurities from the raw material surface. However, this method is performed in the atmosphere and cannot be used to treat waste nickel mesh because it would cause the surface of the waste nickel mesh to become brittle and fragile due to the absorption of gases or chemical reactions with air components, making complete removal difficult. Existing stripping methods have drawbacks, including the need for chemical solvents, resulting in environmental pollution from residual liquids or released gases. They are also costly, have poor stripping efficiency at lower temperatures, and cause the scrap nickel mesh to become brittle and break. Therefore, there is still considerable room for improvement in scrap nickel mesh surface stripping technology. Summary of the Invention

[0004] The purpose of this invention is to provide an efficient method for thermally stripping photosensitive adhesive from the surface of waste nickel mesh, so as to ensure the efficient separation and recycling of nickel resources and surface photosensitive adhesive, reduce pollution emissions and save water resources.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A highly efficient thermal stripping method for photosensitive adhesive on the surface of waste nickel mesh includes the following steps: 1) Inspect the nickel mesh to remove large particles adhering to the surface; 2) Place the inspected nickel mesh into the atmosphere furnace. Evacuate the atmosphere furnace and introduce nitrogen gas. Control the nitrogen gas introduction rate at 10~20mL / min. After introducing nitrogen, maintain the pressure inside the atmosphere furnace below 0.05 MPa. 3) Under nitrogen protection, heat to 300~600℃ and hold at that temperature for 0.5~5h to melt and recover the photosensitive adhesive on the nickel mesh surface; 4) After the constant temperature is completed, stop the nitrogen gas supply and switch to air supply into the atmosphere furnace. The air supply rate is controlled at 50~70mL / min. Keep the pressure inside the atmosphere furnace below 0.05 MPa and continue to maintain the constant temperature for 0.5-1h. After heating is completed, slowly cool to room temperature, remove the nickel mesh and collect the photosensitive adhesive recycled material.

[0006] The recycling principle of this invention is as follows: Based on the boiling points of the components of the photosensitive emulsion, this invention performs non-decompositional evaporation under a nitrogen atmosphere, which then condenses to form a recycled photosensitive emulsion. The non-volatile substances remaining on the nickel surface are decomposed into CO2 gas components by oxygen in the air and the catalytic action of Ni, thus achieving physical separation of the photosensitive emulsion from the nickel mesh. The recycled photosensitive emulsion can be quantitatively analyzed and then re-formulated to prepare new photosensitive emulsion coatings.

[0007] In summary, this invention, based on physical evaporation and chemical oxidation, develops a highly efficient thermal stripping technology for the photosensitive adhesive on waste nickel mesh, simultaneously achieving the recovery of both the photosensitive adhesive and the nickel mesh. This method differs from traditional incineration methods, avoiding the generation of toxic and harmful gases such as CO, SO2, NO, and NO2; it also differs from adhesive stripping agent-assisted stripping, simplifying the nickel mesh stripping operation, reducing water resource input and wastewater discharge, and generating no new waste. Attached Figure Description

[0008] Figure 1 This is a liquid chromatography-mass spectra of the photosensitive adhesive recycled material obtained in this invention.

[0009] Figure 2 These are the XRD diffraction peaks before and after nickel mesh treatment according to the present invention.

[0010] Figure 3 These are morphological images of the nickel mesh before and after processing according to the present invention. Detailed Implementation

[0011] The photosensitive adhesive peeling process of the present invention will be explained below with reference to specific embodiments. Example

[0012] The waste nickel mesh mainly comes from discarded printing nickel mesh from a printing factory in Jiangsu.

[0013] 1) Inspect 200g of nickel mesh to remove large particles such as sawdust, cloth scraps, and adobe adhering to the surface; 2) Place the inspected nickel mesh into the atmosphere furnace. Evacuate the atmosphere furnace and introduce nitrogen gas. The nitrogen gas introduction rate is controlled at 15 mL / min. After introducing nitrogen, the pressure inside the atmosphere furnace is maintained at 0.05 MPa. 3) Under nitrogen protection, heat to 300~600℃ and hold at that temperature for 0.5~5h to melt and recover the photosensitive adhesive on the nickel mesh surface; 4) After the constant temperature is completed, stop the nitrogen gas supply and switch to air supply into the atmosphere furnace. The air supply rate is controlled at 60 mL / min. Maintain the pressure inside the atmosphere furnace at 0.05 MPa and continue to maintain the constant temperature for 0.5-1 h. After heating is completed, slowly cool to room temperature, remove the nickel mesh and collect the photosensitive adhesive recycled material.

[0014] Process evaluation: For the composition of the photosensitive adhesive before treatment, please refer to the following literature: Wang Chao, Li Li, Huang Yudong. Medium-temperature curing, high-strength, high-peel solvent-free polyurethane modified epoxy resin structural adhesive [J]. Journal of Natural Science of Heilongjiang University, 2003, (03): 109-111. Figure 1 This is the mass spectrum of the photosensitive adhesive recovery solution obtained in this invention. In the spectrum, peaks at m / z=141 and 163 represent the hydrogenation and sodium addition peaks of tetrabutylene diisocyanate; m / z=321 represents the monomer hydrogenation peak of poly(butadiene-acrylonitrile); and m / z=393, 449, and 493 represent the monomer hydrogenation peaks of ethylene oxide-polysulfone and propylene oxide-polysulfone. This indicates that the recovered material is mainly a mixture of isocyanate, poly(butadiene-acrylonitrile), alkyl epoxides, and polysulfone, proving that this process can effectively recover the photosensitive adhesive from the surface of waste nickel mesh.

[0015] Figure 2 The figures show the XRD diffraction peaks of the nickel mesh before and after treatment according to the present invention. Before treatment, the nickel mesh is mainly oriented at (200); after treatment, the nickel mesh is mainly oriented at (111), and also contains diffraction peaks of NiO. The main reason for the change in the orientation of the diffraction peaks before and after treatment is that the non-volatile C produced by inert decomposition interacts with the Ni surface to form NiC active material. Under the presence of oxygen, NiC is transformed into metallic Ni and CO2, thus changing the peak shape; some of the metallic Ni on the surface is oxidized by oxygen in the air to form NiO.

[0016] Figure 3 These are morphological images of the nickel mesh before (top) and after (bottom) treatment according to the present invention. Compared to before treatment, the nickel mesh exhibits good uniformity in aperture size and no residual adhesive adheres, proving that the adhesive removal process of the present invention is reliable.

Claims

1. A highly efficient thermal stripping method for photosensitive adhesive on the surface of waste nickel mesh, characterized in that, Includes the following steps: 1) Inspect the nickel mesh to remove large particles adhering to the surface; 2) Place the inspected nickel mesh into the atmosphere furnace. Evacuate the atmosphere furnace and introduce nitrogen. After introducing nitrogen, maintain the pressure inside the atmosphere furnace below 0.05 MPa. 3) Under nitrogen protection, heat to 300~600℃ and hold at that temperature for 0.5~5h to perform non-decomposition evaporation and recovery of the photosensitive adhesive on the nickel mesh surface; 4) After the treatment in step 3) is completed, stop the nitrogen gas supply and change the air supply into the atmosphere furnace. Keep the pressure inside the atmosphere furnace below 0.05 MPa and continue to keep the temperature constant for 0.5-1h. After heating is completed, slowly cool to room temperature, remove the nickel mesh and collect the photosensitive adhesive recycled material.

2. The efficient thermal stripping method for photosensitive adhesive on the surface of waste nickel mesh as described in claim 1, characterized in that, In step 2), the nitrogen flow rate is controlled at 10~20 mL / min.

3. The efficient thermal stripping method for photosensitive adhesive on the surface of waste nickel mesh as described in claim 1, characterized in that, In step 4), the air flow rate is controlled at 50~70 mL / min.

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