Acrylic plate environment-friendly manufacturing process with low waste gas emission

Abstract

The invention belongs to the technical field of high-molecular compounds, and particularly relates to an environment-friendly manufacturing process of an acrylic plate with low exhaust emission. The process comprises the following steps: recycling waste acrylic plates, cleaning and cutting into cracking raw materials; raw material gas is filled into the base material polymerization cavity, and sealed stirring and positive and negative pressure fluctuation circulation are carried out; heating and controlling pressure to primarily polymerize and form the raw materials into a cracking polymerization plate, and stacking the formed plates in multiple layers; feeding the material into a cracking cavity through a gas extraction device for replacing the raw material for cracking, and setting periodic circulation; after exhausting and degumming are completed in the polymerization cavity, filling polymerization gas to perform lamination forming, finally obtaining an acrylic plate plain plate, and performing hot cutting and trimming to form a finished product acrylic plate; meanwhile, a waste gas recovery system is arranged to condense and filter waste gas and recover methacrylic acid and methanol. The process effectively reduces waste gas emission, improves the utilization rate of raw materials and the quality of finished products, and is suitable for continuous large-scale production of environment-friendly acrylic plates.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer compounds, and in particular relates to an environmentally friendly manufacturing process for acrylic panels with low waste gas emissions. Background Art

[0002] Acrylic sheets, typically polymethyl methacrylate (PMMA), offer excellent transparency, weather resistance, and workability, making them widely used in architectural decoration, advertising signage, transportation, medical equipment, and other fields. Existing acrylic sheet manufacturing processes primarily include casting and extrusion, with casting being the more widely used method due to its high-quality products.

[0003] Traditional acrylic sheet manufacturing processes typically involve the polymerization of the monomer methyl methacrylate (MMA), requiring the use of large quantities of initiators, solvents, and other additives. These materials are prone to generating volatile organic compounds (VOCs) and other harmful gases, such as benzene, formaldehyde, and small amounts of unreacted monomers, during polymerization, molding, and post-processing. These waste gases not only pollute the production environment but also pose a threat to the health of operators, increasing the cost of emission control and compliance.

[0004] To reduce waste gas emissions, some existing technical solutions have been developed by optimizing raw material formulations, improving polymerization reaction conditions, adopting closed reaction systems, and adding waste gas treatment devices to reduce harmful gas emissions. However, existing technologies still have the following shortcomings:

[0005] Although some processes have controlled waste gas emissions, the polymerization reaction itself still uses a large amount of traditional monomers and additives, making it difficult to effectively reduce emissions at the source; while some environmentally friendly acrylic board manufacturing processes reduce waste gas emissions, they often sacrifice the transparency, impact resistance or mechanical properties of the products, making it difficult to balance environmental protection requirements with product quality requirements.

[0006] Therefore, how to provide an environmentally friendly manufacturing process that can effectively control waste gas emissions at the source, take into account the performance indicators of acrylic boards, and at the same time have the characteristics of simple process and suitability for large-scale production has become a technical problem that needs to be solved urgently in this field. Summary of the Invention

[0007] In view of the above problems existing in the prior art, the present invention aims to provide an environmentally friendly manufacturing process for acrylic panels with low waste gas emissions, comprising the following steps:

[0008] S1. Recycling of waste boards: Recycling of discarded acrylic boards;

[0009] S2, cracking polymerization: filling, sealing and stirring the substrate polymerization chamber with raw material gas, and performing positive and negative pressure fluctuation circulation;

[0010] S3, forming substrate: after the raw material gas treatment is completed, the raw material is initially polymerized and formed in the polymerization chamber by heating and controlling the pressure to obtain a cracked polymerized plate with a certain thickness and strength;

[0011] S4, stacking the formed cracking and polymerizing plates in multiple layers: After the formed cracking and polymerizing plates are taken out, they are stacked in multiple layers in a predetermined order to prepare for subsequent raw material replacement cracking and lamination polymerization operations;

[0012] S5. Replacement of raw materials for cracking: The material is taken from the material pool of the gas extraction device and fed into the cracking chamber. The material is sunk into the slurry by negative pressure to perform pre-cracking. Positive and negative pressure fluctuations are simultaneously performed to promote the reaction.

[0013] S6, cycle: a portion of the material in the molten pool is precipitated into a precipitation tank. After the material is extracted to a preset height, the process returns to step S5 and performs at least five cycles of replacing the raw material cracking and precipitated gas extraction;

[0014] S7, exhaust and glue removal: exhaust the last pre-cracking gas in the polymerization chamber through the external gas outlet valve;

[0015] S8, polymerization molding and lamination: filling the polymerization cavity of the substrate with polymerization gas, and undergoing polymerization, molding and degassing and degumming operations to obtain an acrylic sheet;

[0016] S9, trimming: hot cutting the acrylic sheet to obtain the target finished acrylic sheet;

[0017] S10, waste gas recovery and cracking recovery of methacrylic acid and methanol: the gas in the polymerization chamber is pumped into the waste gas recovery device for treatment.

[0018] Furthermore, the step S1 of recycling the discarded acrylic sheet specifically includes: recycling the discarded acrylic sheet after use, performing cleaning and decontamination operations to remove stains and adhesions on the surface of the polymethyl methacrylate, and using cutting equipment to cut the entire piece of discarded acrylic sheet into strips and blocks of cracked raw materials of preset sizes.

[0019] Furthermore, the step S5 specifically includes the following steps:

[0020] S51, cutting and taking materials from the material pool of the gas extraction device and sending them into the cracking chamber in the gas extraction device;

[0021] S52, sinking the slurry: while performing the substrate forming operation, opening the second valve of the valve group to sink the material in the molten pool into the cracking chamber in the gas extraction device under negative pressure;

[0022] S53, pre-cracking: pre-cracking the gaseous material in the polymerization chamber, so that the pre-cracking gas enters the polymerization chamber through the gas inlet valve;

[0023] S54, positive and negative pressure stirring: while performing pre-cracking, controlling the air pump to perform positive and negative pressure fluctuation stirring on the polymerization chamber.

[0024] Furthermore, the positive and negative pressure fluctuation stirring in step S54 specifically includes:

[0025] S541: Maintaining the internal pressure of the polymerization chamber at 1 / 3 of the external pressure, injecting the pre-cracking gas in the cracking chamber into the polymerization chamber at a preset flow rate;

[0026] S542: When the pressure in the polymerization chamber reaches three times the external air pressure, the gas outlet is opened to output excess pre-cracking gas into the cracking chamber at a first preset flow rate;

[0027] S543: When the air pressure in the polymerization chamber drops to 1 / 3 of the external air pressure, close the air outlet and repeat steps S541 and S542.

[0028] Furthermore, in step S6, part of the material in the molten pool is precipitated into a sedimentation tank, and a positive and negative pressure stirring method is adopted, and the positive and negative pressure ratio is controlled to be 1:3.

[0029] Furthermore, in step S10, the gas in the polymerization chamber is pumped into a waste gas recovery device for treatment, specifically including: after the waste gas is filtered and condensed in the waste gas recovery device, methacrylic acid and methanol are cracked and recovered to produce polymethyl methacrylate.

[0030] Furthermore, the polymer molding lamination in step S8 specifically includes: gluing the surfaces of two or more polymer plates, placing the polymer plates in a mutually bonded state into a heating and pressing tank, heating the temperature to 120°C at a heating rate of 4°C / min, and performing venting and pressing operations while heating.

[0031] Furthermore, the exhaust and pressing operations during heating specifically include: exhausting excess gas in the substrate polymerization cavity at a preset speed, and slowly pressurizing at 0.2 MPa. When the pressure in the polymerization cavity reaches 1 / 4 of the external air pressure, pressurizing and exhausting are stopped to keep the internal pressure of the polymerization cavity constant.

[0032] The present invention also provides an environmentally friendly manufacturing device for acrylic panels with low waste gas emissions, which is used to implement the environmentally friendly manufacturing process for acrylic panels with low waste gas emissions. The device includes:

[0033] Exhaust gas recovery device: the exhaust gas recovery device is used to collect the generated exhaust gas;

[0034] Substrate polymerization chamber: The substrate polymerization chamber is used for polymerization of raw material gas, degassing and degumming, and polymerization molding of multi-layer board materials. A stirring paddle is provided in the substrate polymerization chamber to stir the internal gas with positive and negative pressure fluctuations. The substrate polymerization chamber is also provided with an air inlet valve and an air outlet valve;

[0035] Gas extraction device: The gas extraction device includes a cracking chamber and a polymerization chamber;

[0036] The cracking chamber is provided with a valve group, which includes a first valve and a second valve connected to the gas inlet valve, and is used to introduce the pre-cracking gas generated in the cracking chamber into the substrate polymerization chamber;

[0037] The polymerization chamber is used for polymerization extraction and separation of impurities, and is provided with an air outlet; the air outlet is connected to the air inlet valve of the substrate polymerization chamber through a pipeline, and an air pump is provided at the air outlet.

[0038] Cutting chamber: The cutting chamber includes an opening and closing cover and an inlet and an outlet arranged on the opening and closing cover. The inlet and the outlet are both provided with air lock valves, and a cutting tool is provided in the cutting chamber.

[0039] Furthermore, the waste gas recovery device is provided with a return pipeline, which is connected to the substrate polymerization chamber. The waste gas recovery device extracts polymethyl methacrylate from the waste gas according to a preset ratio and inputs the extracted polymethyl methacrylate into the substrate polymerization chamber.

[0040] Beneficial effects

[0041] The present invention provides an environmentally friendly manufacturing process for acrylic sheets with low waste gas emissions and its supporting equipment. This process addresses the problems of large waste gas emissions, high environmental pressure, and high energy consumption in the existing acrylic sheet production process. It proposes a comprehensive solution combining source control and process optimization, and has the following beneficial effects:

[0042] 1. Significantly reduce waste gas emissions: By adopting steps such as waste plate recycling, cracking polymerization, pre-cracking gas treatment, and positive and negative pressure fluctuation stirring, efficient cracking and reuse of raw materials are achieved, significantly reducing the emission of volatile organic compounds (VOCs) such as methyl methacrylate, meeting the requirements of green and environmentally friendly production.

[0043] 2. Improve the utilization rate of raw materials: The present invention maximizes the recovery of methacrylic acid and methanol components by cracking the original waste acrylic sheet and recycling it, reducing the demand for new raw materials, reducing raw material costs, and improving resource utilization efficiency.

[0044] 3. Improve the quality of finished products: During the substrate molding and multi-layer stacking stages, the optimized heating rate and positive and negative pressure control process are used to effectively avoid common defects such as bubbles and cracks, ensuring the excellent transparency, mechanical properties and dimensional stability of the acrylic sheet.

[0045] 4. Continuous and efficient process flow: By setting up periodic replacement of raw material cracking and precipitation extraction steps, and synchronously performing exhaust and pressing during the polymerization molding process, continuous and automated production can be achieved, which improves production efficiency and shortens the board making cycle.

[0046] In summary, the present invention has achieved remarkable technical effects in reducing waste gas emissions, improving resource utilization, ensuring the performance of acrylic sheet products, and optimizing production costs and efficiency, and has good prospects for promotion and application and market competitiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 Schematic diagram of the method of the present invention. DETAILED DESCRIPTION

[0048] In order to deepen the understanding of the present invention, the present invention will be further described in detail below with reference to the examples. The examples are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0049] Example 1

[0050] according to Figure 1 As shown, this embodiment provides an environmentally friendly manufacturing process for acrylic panels with low waste gas emissions, comprising the following steps:

[0051] S1. Recycling of waste boards: Recycling of used waste acrylic boards, cleaning and decontamination operations to remove stains and adhesions on the surface of polymethyl methacrylate, and using cutting equipment to cut the entire waste acrylic board into strips and blocks of pre-set sizes for cracking raw materials;

[0052] S2, cracking polymerization: filling, sealing and stirring the substrate polymerization chamber with raw material gas, and performing positive and negative pressure fluctuation circulation;

[0053] S3, forming substrate: after the raw material gas treatment is completed, the raw material is initially polymerized and formed in the polymerization chamber by heating and controlling the pressure to obtain a cracked polymerized plate with a certain thickness and strength;

[0054] S4, stacking the formed cracking and polymerizing plates in multiple layers: After the formed cracking and polymerizing plates are taken out, they are stacked in multiple layers in a predetermined order to prepare for subsequent raw material replacement cracking and lamination polymerization operations;

[0055] S5. Replacement of raw materials for cracking: The material is taken from the material pool of the gas extraction device and fed into the cracking chamber. The material is sunk into the slurry by negative pressure to perform pre-cracking. Positive and negative pressure fluctuations are simultaneously performed to promote the reaction.

[0056] S6, cycle: a portion of the material in the molten pool is precipitated into a precipitation tank. After the material is extracted to a preset height, the process returns to step S5 and performs at least five cycles of replacing the raw material cracking and precipitated gas extraction;

[0057] S7, exhaust and glue removal: exhaust the last pre-cracking gas in the polymerization chamber through the external gas outlet valve;

[0058] S8, polymerization, molding and lamination: A polymerization gas is filled into the polymerization chamber of the substrate, and after polymerization, molding and degassing and degumming operations, an acrylic sheet is obtained; the surfaces of two or more polymer sheets are glued together, and the polymer sheets are placed in a heated and pressed filling tank in a state of being bonded to each other, and the temperature is increased to 120°C at a heating rate of 4°C / min, and degassing and pressing operations are performed while heating;

[0059] S9, trimming: hot cutting the acrylic sheet to obtain the target finished acrylic sheet;

[0060] S10, waste gas recovery and cracking recovery of methacrylic acid and methanol: the gas in the polymerization chamber is pumped into the waste gas recovery device for treatment.

[0061] Example 2

[0062] This embodiment is further limited based on the embodiment 1:

[0063] Step S5 specifically includes the following steps:

[0064] S51, cutting and taking materials from the material pool of the gas extraction device and sending them into the cracking chamber in the gas extraction device;

[0065] S52, sinking the slurry: while performing the substrate forming operation, opening the second valve of the valve group to sink the material in the molten pool into the cracking chamber in the gas extraction device under negative pressure;

[0066] S53, pre-cracking: pre-cracking the gaseous material in the polymerization chamber, so that the pre-cracking gas enters the polymerization chamber through the gas inlet valve;

[0067] S54, positive and negative pressure stirring: while pre-cracking, controlling the air pump to perform positive and negative pressure fluctuation stirring on the polymerization chamber; the positive and negative pressure fluctuation stirring in step S54 specifically includes:

[0068] S541: Maintaining the internal pressure of the polymerization chamber at 1 / 3 of the external pressure, injecting the pre-cracking gas in the cracking chamber into the polymerization chamber at a preset flow rate;

[0069] S542: When the pressure in the polymerization chamber reaches three times the external air pressure, the gas outlet is opened to output excess pre-cracking gas into the cracking chamber at a first preset flow rate;

[0070] S543: When the air pressure in the polymerization chamber drops to 1 / 3 of the external air pressure, close the air outlet and repeat steps S541 and S542.

[0071] Example 3

[0072] This embodiment provides an environmentally friendly manufacturing process for acrylic panels with low waste gas emissions. The process mainly relies on the recycling and utilization of waste acrylic panels. Through an optimized cracking polymerization and lamination molding process, the regeneration preparation of polymethyl methacrylate materials is achieved. The positive and negative pressure control and waste gas recovery mechanism of the entire process system greatly reduces the emission of organic waste gas, thereby improving overall production efficiency and environmental friendliness.

[0073] Specifically, the process includes the following steps:

[0074] S1. Recycling of waste boards

[0075] First, discarded acrylic sheets generated during use are sorted and recycled. Scrap sheets with impurities such as oil, dust, and coatings are sequentially passed through a cleaning device and scrubbed with a weak alkaline solution and a soft-bristled brush. The cleaned sheets are then dried with hot air in a drying device to remove any residual surface moisture, ensuring no moisture can interfere with subsequent operations.

[0076] Subsequently, the dried waste board is resized using intelligent cutting equipment, and the entire acrylic board is cut into strips and blocks of cracking raw materials of about 100mm×100mm according to process requirements, so that they can subsequently enter the gas cracking system for pyrolysis and polymerization.

[0077] S2, cracking polymerization

[0078] The cut cracking raw materials are fed into the substrate polymerization chamber in sequence and filled through the feeding valve. The air sealing system is connected to seal the cavity. Subsequently, the stirring mechanism is started to stir the raw materials inside the cavity at a low speed and uniformly. At the same time, the air pump is controlled to implement a positive and negative pressure fluctuation cycle, that is, the pressure inside the polymerization chamber is gradually increased from 1 / 3 of the external air pressure to 3 times the atmospheric pressure, and then quickly released to the initial state, forming a complete pressure difference fluctuation process. This cycle is performed 3 to 5 times in a row, which helps to decompose impurities and residual gases in the polymerization chain segments in advance and promote the uniformity of subsequent polymerization reactions.

[0079] S3, molding substrate

[0080] After the pyrolysis polymerization is complete, constant heating is applied to the interior of the polymerization chamber, with the temperature being steadily raised to 85°C-95°C by a temperature control device and maintained for 20-30 minutes. This allows the raw materials to complete initial polymerization under the dual effects of pressure and temperature. During the polymerization process, the raw materials gradually deposit at the bottom of the chamber to form a polymer of a certain thickness, which becomes a pyrolysis polymer plate with basic strength. The thickness of this plate can be adjusted according to the desired specifications of the finished plate, typically ranging from 3mm to 6mm.

[0081] S4, multi-layer stacking

[0082] The pre-cured pyrolysis polymer sheets in the polymerization chamber are removed by a robotic arm and stacked according to the set stacking sequence. During the stacking process, a suitable amount of high-temperature adhesive is sprayed between the sheets to ensure adhesion and polymerization between the multiple layers. After the multi-layer stacking is completed, the entire slab enters the processing area, ready for the next round of raw material replacement and pyrolysis.

[0083] S5. Replacement of raw material cracking

[0084] This step consists of the following sub-steps:

[0085] S51: By controlling the cutting device, new cracking raw material blocks are cut from the material pool of the gas extraction device and are sent into the cracking chamber of the gas extraction device through a closed conveyor belt.

[0086] S52: while the substrate is being formed, the second valve is opened, and the slurry reactants in the molten pool are extracted by a negative pressure pump and sucked into the cracking chamber for mixing;

[0087] S53: preheating the cracking chamber using a built-in heating element, so that the original gas material in the polymerization chamber begins to crack when the temperature reaches 120° C., releasing pre-cracking gas;

[0088] S54: Control the air pump to start positive and negative pressure fluctuation stirring to fully mix the pre-cracking gas. During the fluctuation stirring operation, the pressure inside the polymerization chamber changes cyclically between 1 / 3 of the external pressure and 3 times the pressure.

[0089] S6, Cycle

[0090] After a single replacement cracking cycle, the pyrolysis residue is piped into a sedimentation tank, where heavy materials are separated by sedimentation. Alternating positive and negative pressure stirring technology is used to ensure sufficient sedimentation. A height sensor is installed. When the slurry level in the sedimentation tank reaches a set height, it is automatically pumped out and returned to the cracking chamber, repeating step S5. This entire process is repeated continuously for at least five cycles to ensure a complete reaction and a pure product.

[0091] S7, exhaust and glue removal

[0092] After the cyclic cracking cycle is complete, the external gas outlet valve is controlled to open, quickly extracting the remaining pre-cracking gas from the polymerization chamber and vacuum-evacuating the chamber. This step prevents defects such as blistering and glue residue on the board caused by residual gas.

[0093] S8, polymer molding lamination

[0094] The stacked polymer sheets are fed into a heated pressure-filling tank to initiate polymerization. Polymerization gas is introduced into the polymerization chamber through an inlet valve, and the reaction is completed as the internal temperature rises from room temperature to 120°C at a rate of 4°C / min. Simultaneous vacuum exhaust and slow pressurization at 0.2 MPa ensure uniform diffusion of the adhesive between the sheets and complete the compact lamination and curing. The control system determines the reaction progress based on the air pressure. Once the pressure inside the polymerization chamber is maintained at a constant level of 1 / 4 of the external pressure, it remains unchanged to ensure molding stability.

[0095] S9, trimming

[0096] After forming, the unfinished acrylic sheets are transported to the hot-cutting area, where they are cut to the desired dimensions using precision cutting equipment. Depending on the intended use, they can be cut into rectangular sheets, circular sheets, or other custom sizes. The trimmed sheets then proceed to the finished product inspection area, where they are tested for parameters such as thickness, gloss, impact resistance, and transparency.

[0097] S10, waste gas recovery and cracking reuse

[0098] Exhaust gases from each process stage are collected through pipelines and fed into an exhaust gas recovery unit. This unit comprises a condensing unit, a filtration module, and a return line. The condensation system condenses and recovers methacrylic acid and methanol from the exhaust gas, which are then resynthesized into polymethyl methacrylate monomer through a catalytic reaction unit for subsequent production. Uncondensed exhaust gas is treated by adsorption in the filtration module before meeting emission standards. Some recyclable materials are then re-introduced into the polymerization chamber via a return line, further enhancing the system's closed-loop efficiency and environmental performance.

[0099] In summary, this embodiment integrates raw material cracking, polymerization, lamination, and waste gas recovery technologies to provide an efficient, environmentally friendly, closed-loop acrylic sheet manufacturing method. This method offers numerous advantages, including low emissions, low cost, and high quality, making it suitable for widespread application in the modern materials processing industry. This process not only improves waste recycling efficiency but also significantly reduces volatile organic compound emissions, meeting the requirements of green manufacturing and sustainable development.

[0100] Example 4

[0101] In this embodiment, the equipment includes an exhaust gas recovery device, a substrate polymerization chamber, a gas extraction device and a cutting chamber. The components are organically connected through pipes, gas valves and a control system to form a continuous, closed-loop operation process.

[0102] 1. Waste gas recovery device

[0103] The exhaust gas recovery unit collects and treats exhaust gas generated during the manufacturing process, preventing the direct release of volatile organic compounds into the environment. It comprises a condensing unit, a filtration unit, and a reflux piping system. The exhaust gas first passes through the condensation module, where components such as methacrylic acid and methanol are liquefied and recovered at low temperatures. Uncondensed exhaust gas then enters a multi-layer filtration module for further purification through processes such as activated carbon adsorption or catalytic decomposition. The purified gas emissions meet national environmental standards.

[0104] The waste gas recovery unit is equipped with a return line connected to the substrate polymerization chamber. The recovered methyl methacrylate monomer is re-transferred to the substrate polymerization chamber in a certain proportion for subsequent cracking and polymerization operations, thus achieving raw material recycling and reducing production costs and raw material consumption.

[0105] 2. Substrate polymerization chamber

[0106] The substrate polymerization chamber is the core component for the primary polymerization reaction and sheet forming. Its enclosed interior is resistant to high temperatures and corrosion, and can withstand high positive and negative pressure fluctuations. A stirring paddle is installed within the chamber, connected to an external motor via a central drive shaft. This paddle provides a timed, constant, and adjustable stirring action, ensuring uniform mixing of the gas and preliminary polymer within the chamber and preventing partial polymerization or the formation of bubbles.

[0107] The top of the polymerization chamber is equipped with an inlet valve and an outlet valve. The inlet valve is connected to a gas extraction device to receive pre-cracking gas, while the outlet valve is connected to an exhaust gas recovery device to promptly remove gaseous impurities generated during the reaction and maintain a stable atmosphere within the chamber. Furthermore, pressure and temperature sensors are installed within the chamber to monitor internal conditions in real time and, in conjunction with the central control system, precisely control polymerization reaction parameters.

[0108] The substrate polymerization cavity is also equipped with a glue discharge port. At the end of the polymerization molding, the residual gas and glue residue in the cavity are discharged through the external air outlet valve to further ensure the purity and surface smoothness of the board.

[0109] 3. Gas extraction device

[0110] The gas extraction device comprises two parts, a cracking chamber and a polymerization chamber, which are connected to each other through a built-in channel.

[0111] Cracking Chamber: This chamber performs preliminary thermal cracking on the cut scrap board material. A heating module is installed within the cracking chamber, raising the chamber temperature to 120°C to 150°C through electrical or external steam heating. This promotes the breakage of polymer chains in the feedstock, releasing methyl methacrylate monomer and a small amount of auxiliary components. The cracking chamber is equipped with a valve assembly, including a first valve and a second valve. The first valve controls the discharge of cracked gas, while the second valve is directly connected to the inlet valve of the substrate polymerization chamber, introducing the generated pre-cracking gas into the polymerization chamber for further polymerization.

[0112] Polymerization Chamber: The polymerization chamber within the gas extraction unit assists in gas polymerization and impurity extraction and separation. Pre-cracked gas is further heated and stirred within the polymerization chamber, separating unreacted monomers from light impurities. Light gases are discharged through the outlet to the exhaust gas recovery unit, while the active monomers enter the substrate polymerization chamber for polymerization and formation.

[0113] The gas extraction device is also provided with an air pump, which is installed at the gas outlet to provide the necessary gas flow power during the positive and negative pressure switching process to ensure the continuity and stability of the extraction and transmission process.

[0114] 4. Cutting cavity

[0115] The cutting chamber is used to perform preliminary sizing on recycled acrylic sheets, ensuring the efficiency of subsequent cracking operations and the quality of the finished product. The compact and well-sealed cutting chamber houses high-precision cutting tools that can be programmed to produce strips, blocks, or sheets.

[0116] The cutting chamber includes an opening and closing cover with an inlet and outlet for easy access of raw materials. To prevent gas leakage and the ingress of impurities, both the inlet and outlet are equipped with air lock valves. These air lock valves are linked to the central control system to ensure stable pressure during switching, preventing gas contamination or energy loss during operation.

[0117] The cut raw materials can be directly fed into the gas extraction device through a closed conveying system, forming a continuous operation chain and improving overall production efficiency.

[0118] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. An environmentally friendly manufacturing process for acrylic sheets with low waste gas emissions, characterized in that: The following steps are involved: S1. Recycling of waste boards: Recycling of discarded acrylic boards; S2, cracking polymerization: filling, sealing and stirring the substrate polymerization chamber with raw material gas, and performing positive and negative pressure fluctuation circulation; S3, forming substrate: after the raw material gas treatment is completed, the raw material is initially polymerized and formed in the polymerization chamber by heating and controlling the pressure to obtain a cracked polymerized plate with a certain thickness and strength; S4, stacking the formed cracking and polymerizing plates in multiple layers: After the formed cracking and polymerizing plates are taken out, they are stacked in multiple layers in a predetermined order to prepare for subsequent raw material replacement cracking and lamination polymerization operations; S5. Replacement of raw materials for cracking: The material is taken from the material pool of the gas extraction device and fed into the cracking chamber. The material is sunk into the slurry by negative pressure to perform pre-cracking. Positive and negative pressure fluctuations are simultaneously performed to promote the reaction. S6, cycle: a portion of the material in the molten pool is precipitated into a precipitation tank. After the material is extracted to a preset height, the process returns to step S5 and performs at least five cycles of replacing the raw material cracking and precipitated gas extraction; S7, exhaust and glue removal: exhaust the last pre-cracking gas in the polymerization chamber through the external gas outlet valve; S8, polymerization molding and lamination: filling the polymerization cavity of the substrate with polymerization gas, and undergoing polymerization, molding and degassing and degumming operations to obtain an acrylic sheet; S9, trimming: hot cutting the acrylic sheet to obtain the target finished acrylic sheet; S10, waste gas recovery and cracking recovery of methacrylic acid and methanol: the gas in the polymerization chamber is pumped into the waste gas recovery device for treatment.

2. The environmentally friendly manufacturing process for acrylic sheets with low waste gas emissions according to claim 1, characterized in that: The recycling of the discarded acrylic sheet in step S1 specifically includes: recycling the used discarded acrylic sheet, performing a cleaning and decontamination operation to remove stains and adhesions on the surface of the polymethyl methacrylate, and using a cutting device to cut the entire discarded acrylic sheet into strips and blocks of cracked raw materials of a preset size.

3. The environmentally friendly manufacturing process for acrylic sheets with low waste gas emissions according to claim 1, characterized in that: The step S5 specifically includes the following steps: S51, cutting and taking materials from the material pool of the gas extraction device and sending them into the cracking chamber in the gas extraction device; S52, sinking the slurry: while performing the substrate forming operation, opening the second valve of the valve group to sink the material in the molten pool into the cracking chamber in the gas extraction device under negative pressure; S53, pre-cracking: pre-cracking the gaseous material in the polymerization chamber, so that the pre-cracking gas enters the polymerization chamber through the gas inlet valve; S54, positive and negative pressure stirring: while performing pre-cracking, controlling the air pump to perform positive and negative pressure fluctuation stirring on the polymerization chamber.

4. The environmentally friendly manufacturing process for acrylic panels with low waste gas emissions according to claim 3, characterized in that: The positive and negative pressure fluctuation stirring in step S54 specifically includes: S541: Maintaining the internal pressure of the polymerization chamber at 1 / 3 of the external pressure, injecting the pre-cracking gas in the cracking chamber into the polymerization chamber at a preset flow rate; S542: When the pressure in the polymerization chamber reaches three times the external air pressure, the gas outlet is opened to output excess pre-cracking gas into the cracking chamber at a first preset flow rate; S543: When the air pressure in the polymerization chamber drops to 1 / 3 of the external air pressure, close the air outlet and repeat steps S541 and S542.

5. The environmentally friendly manufacturing process for acrylic panels with low waste gas emissions according to claim 1, characterized in that: In step S6, part of the material in the molten pool is precipitated into a sedimentation tank, and a positive and negative pressure stirring method is adopted, and the positive and negative pressure ratio is controlled to be 1:

3.

6. The environmentally friendly manufacturing process for acrylic panels with low waste gas emissions according to claim 1, characterized in that: In step S10, the gas in the polymerization chamber is pumped into a waste gas recovery device for treatment, which specifically includes: after the waste gas is filtered and condensed in the waste gas recovery device, methacrylic acid and methanol are cracked and recovered to produce polymethyl methacrylate.

7. The environmentally friendly manufacturing process for acrylic panels with low waste gas emissions according to claim 1, characterized in that: The polymer molding lamination in step S8 specifically includes: gluing the surfaces of two or more polymer plates, placing the polymer plates in a mutually bonded state into a heating and pressing tank, heating the tank to 120°C at a heating rate of 4°C / min, and performing venting and pressing operations while heating.

8. The environmentally friendly manufacturing process for acrylic panels with low waste gas emissions according to claim 7, characterized in that: The exhaust and pressing operations during heating specifically include: exhausting excess gas in the substrate polymerization cavity at a preset speed, and slowly pressurizing at 0.2 MPa. When the pressure in the polymerization cavity reaches 1 / 4 of the external air pressure, pressurizing and exhausting are stopped to maintain the internal pressure of the polymerization cavity constant.

9. An environmentally friendly manufacturing equipment for acrylic panels with low waste gas emissions, used to implement an environmentally friendly manufacturing process for acrylic panels with low waste gas emissions as claimed in any one of claims 1 to 8, characterized in that: The equipment includes: an exhaust gas recovery device: the exhaust gas recovery device is used to collect the generated exhaust gas; Substrate polymerization chamber: The substrate polymerization chamber is used for polymerization of raw material gas, degassing and degumming, and polymerization molding of multi-layer board materials. A stirring paddle is provided in the substrate polymerization chamber to stir the internal gas with positive and negative pressure fluctuations. The substrate polymerization chamber is also provided with an air inlet valve and an air outlet valve; Gas extraction device: The gas extraction device includes a cracking chamber and a polymerization chamber; The cracking chamber is provided with a valve group, which includes a first valve and a second valve connected to the gas inlet valve, and is used to introduce the pre-cracking gas generated in the cracking chamber into the substrate polymerization chamber; The polymerization chamber is used for polymerization extraction and separation of impurities, and is provided with an air outlet; the air outlet is connected to the air inlet valve of the substrate polymerization chamber through a pipeline, and an air pump is provided at the air outlet. Cutting chamber: The cutting chamber includes an opening and closing cover and an inlet and an outlet arranged on the opening and closing cover. The inlet and the outlet are both provided with air lock valves, and a cutting tool is provided in the cutting chamber.

10. According to the low waste gas emission environmentally friendly acrylic plate manufacturing equipment of claim 9, the waste gas recovery device is provided with a return pipeline, the return pipeline is connected to the substrate polymerization chamber, and the waste gas recovery device extracts polymethyl methacrylate in the waste gas according to a preset ratio and inputs it into the substrate polymerization chamber.

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