Continuous production system for biodegradable polyurethane

Abstract

The invention discloses a continuous production system for biodegradable polyurethane, and relates to the technical field of high polymer material production, and the continuous production system comprises a raw material pretreatment module for drying, filtering, crushing and homogenizing various raw materials and then storing in a sealed manner; the proportioning metering module dynamically adjusts the raw material proportioning and mixes and conveys the raw materials; the continuous reaction module regulates and controls temperature and pressure regionally to push the raw materials to fully react to form a prepolymer; the forming module is matched with a forming process regulation and control parameter guarantee effect; the waste recycling module is used for recycling waste after treating the waste; the quality detection module collects data in real time and feeds back the data; and the control system module adjusts the parameter recording data in a linkage manner to form a traceable file. The full-process continuous production of the biodegradable polyurethane is realized, the production efficiency and the product performance stability are improved, and the forming precision and the raw material purity are guaranteed; resource circulation is realized through closed-loop waste recovery, and the production process is intelligently regulated, controlled and optimized.

Description

Technical Field

[0001] This invention relates to the field of polymer material production technology, and in particular to a continuous production system for biodegradable polyurethane. Background Technology

[0002] With increasing global environmental awareness, the environmental pollution caused by traditional non-degradable plastics is becoming increasingly prominent. Biodegradable polyurethane, as an environmentally friendly material, is widely used in packaging, medical, and agricultural fields because it can gradually degrade into harmless substances in the natural environment, leading to continuous market demand growth. However, current production of biodegradable polyurethane is still mainly based on intermittent production. The various stages of the production process are independent, and the processes such as raw material pretreatment, reaction, and molding are not interconnected, resulting in low production efficiency and an inability to meet the needs of large-scale industrial production. Under the intermittent production mode, it is difficult to maintain consistent pretreatment conditions, proportions, and reaction parameters between batches of raw materials, resulting in large fluctuations in product quality and insufficient stability of key indicators such as mechanical properties and degradation rates, which limits its application in high-end fields.

[0003] While some attempts at continuous production have emerged in the existing technology, numerous technical shortcomings remain. In the raw material pretreatment stage, incomplete removal of moisture from bio-based polyols, insufficient filtration of mechanical impurities in isocyanates, and uneven mixing of degradation accelerators and functional additives directly affect the sufficiency and stability of subsequent reactions. Metering often relies on a single metering method, lacking precision and unable to be dynamically adjusted according to product performance targets, leading to unreasonable raw material ratios and difficulty in balancing the mechanical and degradation properties of biodegradable polyurethane. During continuous reactions, the control of parameters such as temperature and pressure is often crude, lacking real-time monitoring and dynamic control of the reaction process, easily resulting in incomplete or excessive reactions and poor quality prepolymers. Poor adaptability of molding processes makes it difficult to guarantee product dimensional uniformity and molding accuracy. Furthermore, waste materials such as scraps and defective products generated during production lack efficient recycling systems and are mostly discarded directly, causing resource waste and potentially secondary pollution. Furthermore, quality testing is mostly conducted offline, resulting in delayed feedback of test results and an inability to adjust production parameters in a timely manner. This further exacerbates the instability of product quality, and these problems severely restrict the large-scale and high-quality development of the biodegradable polyurethane industry.

[0004] The industry is currently placing higher demands on the production technology of biodegradable polyurethane, urgently requiring a continuous production system capable of coordinating the entire process from raw material pretreatment, proportioning and metering, continuous reaction, molding, waste recycling, and quality inspection. Existing technologies have shortcomings in areas such as the synergy of continuous production, the precision of parameter control, the efficiency of waste recycling, and the real-time nature of quality inspection, making it difficult to balance efficiency, quality, and environmental requirements in the production of biodegradable polyurethane. Therefore, developing a continuous production system with functions including deep raw material pretreatment, precise proportioning and metering, controllable continuous reaction, high-precision molding, closed-loop waste recycling, real-time quality inspection, and intelligent control is crucial for addressing current technological challenges and driving the upgrading of the biodegradable polyurethane industry. Summary of the Invention

[0005] The present invention proposes a continuous production system for biodegradable polyurethane to solve the problems mentioned in the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a continuous production system for biodegradable polyurethane, comprising the following modules: The raw material pretreatment module pretreats bio-based polyols, isocyanates, degradation accelerators, and functional additives respectively; the pretreated raw materials are stored in a sealed storage tank protected by inert gas. The proportioning and metering module uses a combination of a weighing metering pump and an electromagnetic flow meter to collect the flow and mass data of each raw material in real time. Based on the target performance parameters, the proportion of raw materials is adjusted. After the raw materials are initially mixed by a static mixer, they are transported to the continuous reaction module. The continuous reaction module consists of a twin-screw extruder and a series-connected reactor. The twin-screw extruder is equipped with multiple temperature control zones, and the series-connected reactor is equipped with a stirring device and temperature and pressure sensors. The degree of reaction is monitored by an online infrared spectrometer. The molding module receives the prepolymer output from the continuous reaction module and selects either extrusion molding or injection molding process according to product requirements; the extrusion molding unit is equipped with precision molds and pelletizing devices, and the injection molding unit controls the injection pressure and speed through a servo control system; The waste recycling module collects scraps, defective products and reaction residues from the production process. After being crushed by the crushing device, the waste is remelted by the melt extruder, purified and modified by adding chain extenders and degradation regulators, and after removing impurities, it is sent to the proportioning and metering module for recycling. The quality inspection module collects performance data of molded products and recycled raw materials in real time, and uses gel permeation chromatography, universal testing machine and degradation tester for testing. The test results are fed back to the control system module in real time. The control system module uses a PLC controller linked with an industrial computer to receive operating parameters and detection data from each module in real time. It adjusts the raw material ratio, reaction temperature, molding and recycling process parameters through preset algorithms and records production data to form a traceable archive.

[0007] Furthermore, it also includes a raw material ratio optimization module. Based on the target degradation rate and mechanical properties of biodegradable polyurethane, the raw material ratio is determined through a multi-objective optimization algorithm. The specific formula is as follows: in For the first The mass ratio coefficient of the raw materials For the first The reactivity weight of the raw materials For the first The influence coefficient of the raw material on mechanical properties Quantification of target mechanical properties For the first The influence coefficient of the raw material on the degradation rate Quantification of the target degradation rate, This represents the total number of types of raw materials.

[0008] Furthermore, it also includes a dynamic temperature control module for the reaction, which dynamically adjusts the temperature of each section of the continuous reaction module based on the reaction progress and raw material characteristics. The specific formula is as follows: in For the first The target temperature of the reaction zone. Based on the reaction temperature, For the first The influence coefficient of the reaction process at any given time. For the first The reaction conversion rate at any given time. For the first Pressure influence coefficient of the segment area For the first The difference between the pressure of the section area and the standard pressure.

[0009] Furthermore, it also includes a waste recycling and purification module, in which adsorbents and catalysts are added during the waste melting process. The adsorbents selectively adsorb impurities and degradation byproducts in the waste, and the catalysts promote the secondary reaction of unreacted raw materials in the waste. The purification process uses vacuum distillation to remove low-molecular-weight volatiles. After purification, the purity of the recycled raw materials reaches the preset standard, and the mixing ratio of recycled raw materials and new raw materials is dynamically adjusted according to product performance requirements.

[0010] Furthermore, it also includes a molding precision control module, which sets up a laser diameter gauge and an infrared thermometer in the extrusion molding unit to monitor the diameter and temperature of the extruded strip in real time, and adjusts the traction speed and pelletizing knife speed through a servo motor; the injection molding unit is equipped with an in-mold pressure sensor to provide real-time feedback on changes in in-mold pressure and dynamically adjust the injection pressure and holding time.

[0011] Furthermore, it includes a refined quality testing module, which sets up soil burial degradation test units and seawater degradation test units for biodegradability performance, and monitors the degradation rate and degradation products in real time under different environments; a dynamic mechanical analyzer is added for mechanical properties to detect the storage modulus and loss modulus of the product at different temperatures and frequencies; and a gel permeation chromatography is used for online continuous detection of molecular weight distribution, and the detection data generates trend curves in real time. When the data exceeds the preset threshold, the control system module is automatically triggered to adjust the production parameters.

[0012] Furthermore, it also includes an intelligent control system module that integrates machine learning algorithms. Based on historical production data and quality inspection results, it establishes a mapping model between production parameters and product performance, predicts parameter drift trends in advance, and proactively adjusts key indicators. It also supports remote monitoring and operation, pushing production status and quality data and equipment operation status in real time through the industrial internet platform. Abnormal operating conditions automatically trigger alarms and push emergency handling plans.

[0013] Furthermore, it also includes a raw material pretreatment depth optimization module. Bio-based polyols adopt a multi-stage vacuum drying process. The first stage of drying removes free water, and the second stage of drying removes bound water. The drying time is dynamically adjusted according to the initial moisture content of the raw materials. Isocyanate filtration adopts a multi-stage filtration device, and the final filtration accuracy reaches the preset micron level. The mixing of degradation accelerators and functional additives adopts a high-speed mixer, and the mixing speed and time are optimized according to the material characteristics.

[0014] Furthermore, it also includes a continuous reaction multi-stage control module. The twin-screw extruder is set with a feeding section, a melting section, a reaction section, and a homogenization section, and the temperature and speed of each section are independently controlled. The series reactor is set with a front section, a middle section, and a rear section. The front section controls the reaction initiation, the middle section maintains the reaction process, and the rear section promotes the termination of the reaction. The stirring speed and reaction time of each section are dynamically adjusted according to the degree of reaction of the prepolymer.

[0015] Furthermore, it also includes a post-molding processing module. The granular products after molding are cooled to room temperature by a cooling conveyor belt. The cooling medium adopts a combination of air cooling and water cooling, and the cooling rate is dynamically adjusted according to the product particle size. After cooling, the products are screened by a screening device to remove particles of unqualified size. The screened products are then vacuum-packed, and inert gas is filled in during the packaging process to prevent moisture absorption and oxidation. For injection-molded products, stress-relieving annealing treatment is performed, and the annealing temperature and time are optimized according to the product structure and thickness.

[0016] Compared with existing technologies, the beneficial effects of this invention are: In terms of production efficiency and stability, the system seamlessly integrates raw material pretreatment, proportioning and metering, continuous reaction, molding, and waste recycling to form a closed-loop production process. This completely changes the inefficient traditional intermittent production model and significantly improves production efficiency. The raw material pretreatment module ensures the purity and uniformity of raw materials through graded processing and precise control, laying a solid foundation for subsequent reactions. The proportioning and metering module uses a combined metering method and dynamic adjustment strategy to ensure that the raw material proportions are accurately matched to the target performance of the product. The continuous reaction module promotes full reaction of raw materials and reduces side reactions through multi-stage temperature and pressure control and real-time reaction monitoring. Under the linkage of the control system, all modules achieve real-time parameter optimization, effectively reducing product quality fluctuations and improving product performance stability.

[0017] In terms of product quality and adaptability, the molding module significantly improves product dimensional uniformity and molding accuracy through process optimization and precision control, meeting the product requirements of different application scenarios. The quality inspection module covers multiple dimensions of indicators such as molecular weight distribution, mechanical properties, and degradation rate. Combining online real-time detection and offline in-depth detection, it comprehensively controls product quality. The test results are fed back to the control system in real time, enabling timely adjustment of production parameters and further ensuring product quality standards are met. The application of continuous reaction multi-stage control and post-molding processing technology effectively improves the internal structure of the product, enhances its mechanical properties and dimensional stability, and broadens the application range of biodegradable polyurethane.

[0018] In terms of environmental protection and cost control, the waste recycling module constructs a closed-loop recycling system, refining and modifying scraps and substandard products generated during the production process for reuse in production, achieving efficient resource recycling and reducing resource waste and environmental pollution. The intelligent control system integrates machine learning algorithms, which can predict parameter drift trends and proactively adjust them, reducing manual intervention costs and energy consumption. It also supports remote monitoring and emergency response, improving operation and maintenance efficiency. Attached Figure Description

[0019] Figure 1 This is a schematic block diagram of the continuous production system for biodegradable polyurethane proposed in this invention. Figure 2 A bar chart comparing the efficiency of traditional intermittent systems with that of the present invention at each production stage; Figure 3 This is a line graph showing the trend of reaction conversion rate over time during a continuous reaction process. Figure 4 A line graph showing the relationship between system uptime and product performance stability. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. The invention will now be described in further detail with reference to the accompanying drawings.

[0023] Reference Figures 1 to 4 A continuous production system for biodegradable polyurethane, comprising the following modules: The raw material pretreatment module is used to pretreat bio-based polyols, isocyanates, degradation accelerators and functional additives. Bio-based polyols are vacuum dried to remove moisture, and the drying temperature is dynamically adjusted according to the type of raw material. Isocyanates are filtered to remove mechanical impurities. Degradation accelerators and functional additives are pulverized to a preset particle size and then homogenized and mixed. The pretreated raw materials are stored in a sealed storage tank protected by inert gas. The proportioning and metering module uses a combination of a weighing metering pump and an electromagnetic flow meter to collect the flow and mass data of each raw material in real time. Based on the target performance parameters of biodegradable polyurethane, the proportion of each raw material is dynamically adjusted, and the metering accuracy is controlled within a preset range. After the raw materials are initially mixed by a static mixer, they are transported to the continuous reaction module. The continuous reaction module consists of a twin-screw extruder and a series reactor. The twin-screw extruder is equipped with multiple temperature control zones to achieve melt shearing and initial reaction of the raw materials. The series reactor is equipped with a stirring device and temperature and pressure sensors to control the reaction temperature, pressure and residence time, so as to promote the full reaction of the raw materials to form biodegradable polyurethane prepolymer. The degree of reaction is monitored by an online infrared spectrometer during the reaction process. The molding module receives the prepolymer output from the continuous reaction module and selects either extrusion molding or injection molding process according to product requirements. The extrusion molding unit is equipped with a precision mold and pelletizing device, and the uniformity of the pellet size meets the preset standard. The injection molding unit controls the injection pressure and speed through a servo control system to ensure the product molding accuracy. The waste recycling module collects scraps, defective products, and reaction residues generated during the production process. These are crushed to a preset particle size by a crushing device, remelted by a melt extruder, and purified and modified by adding appropriate chain extenders and degradation regulators. After removing impurities, the waste is transported to the proportioning and metering module for recycling, thus achieving closed-loop recycling of waste. The quality inspection module collects performance data of molded products and recycled raw materials in real time, including molecular weight distribution, tensile strength, elongation at break, degradation rate, etc., and uses equipment such as gel permeation chromatography, universal testing machine, degradation tester for testing. The test results are fed back to the control system module in real time. The control system module uses a PLC controller linked with an industrial computer to receive the operating parameters and detection data of each module in real time. It adjusts the raw material ratio, reaction temperature, molding parameters and recycling process parameters through preset algorithms to achieve coordinated linkage of each module, maintain continuous and stable production process, and record production data to form a traceable archive.

[0024] This invention also includes a raw material ratio optimization module. Based on the target degradation rate and mechanical properties of biodegradable polyurethane, the optimal raw material ratio is determined through a multi-objective optimization algorithm. The specific formula is as follows: in For the first The mass ratio coefficient of the raw materials For the first The reactivity weight of the raw materials For the first The influence coefficient of the raw material on mechanical properties Quantification of target mechanical properties For the first The influence coefficient of the raw material on the degradation rate Quantification of the target degradation rate, This represents the total number of raw material types. Through multi-objective optimization logic, the mechanical and degradation properties of biodegradable polyurethane are balanced, avoiding the problem of insufficient product practicality caused by single-performance optimization. This makes the raw material ratio more in line with actual application needs and provides a precise ratio basis for product customization in different application scenarios.

[0025] This invention also includes a dynamic reaction temperature control module, which dynamically adjusts the temperature of each segment of the continuous reaction module based on the reaction progress and raw material characteristics. The specific formula is as follows: in For the first The target temperature of the reaction zone. Based on the reaction temperature, For the first The influence coefficient of the reaction process at any given time. For the first The reaction conversion rate at any given time. For the first Pressure influence coefficient of the segment area For the first The difference between the pressure of the reaction zone and the standard pressure. By dynamically adjusting the reaction temperature based on the real-time reaction conversion rate and the regional pressure, the reaction in each zone is ensured to proceed at the preset rate, avoiding raw material decomposition or incomplete reaction caused by excessively high local temperatures, reducing the probability of side reactions, and improving the reaction uniformity and product performance stability of the biodegradable polyurethane prepolymer.

[0026] This invention also includes a waste recycling and purification module. During the waste melting process, an adsorbent and a catalyst are added. The adsorbent selectively adsorbs impurities and degradation byproducts in the waste, while the catalyst promotes the secondary reaction of unreacted raw materials in the waste. The purification process uses vacuum distillation to remove low-molecular-weight volatiles. After purification, the purity of the recycled raw materials reaches a preset standard. The mixing ratio of recycled raw materials and new raw materials is dynamically adjusted according to product performance requirements to ensure that the recycling of recycled raw materials does not affect the core performance of biodegradable polyurethane.

[0027] This invention also includes a molding precision control module. A laser diameter gauge and an infrared thermometer are installed in the extrusion molding unit to monitor the diameter and temperature of the extruded strip in real time. The traction speed and pelletizing blade speed are adjusted by a servo motor to control the pellet size deviation within a preset range. The injection molding unit is equipped with an in-mold pressure sensor to provide real-time feedback on changes in in-mold pressure and dynamically adjust the injection pressure and holding time to reduce defects such as shrinkage marks and flash, thereby improving the dimensional accuracy and appearance quality of the molded products.

[0028] This invention also includes a quality testing refinement module, which sets up soil burial degradation test units and seawater degradation test units for biodegradability to monitor degradation rates and degradation products in real time under different environments; a dynamic mechanical analyzer is added for mechanical properties to detect the storage modulus and loss modulus of the product at different temperatures and frequencies; and a gel permeation chromatography instrument is used for online continuous detection of molecular weight distribution, with the detection data generating trend curves in real time, and the control system module automatically triggering the adjustment of production parameters when the data exceeds a preset threshold.

[0029] This invention also includes an intelligent control system module that integrates machine learning algorithms. Based on historical production data and quality inspection results, it establishes a mapping model between production parameters and product performance, predicts parameter drift trends during the production process in advance, and proactively adjusts key indicators such as raw material ratio, reaction temperature, and molding parameters. Simultaneously, it supports remote monitoring and operation, pushing production status, quality data, and equipment operation status in real time through an industrial internet platform. Abnormal operating conditions automatically trigger alarms and push emergency response plans, improving the system's intelligence level and operational efficiency.

[0030] This invention also includes a raw material pretreatment depth optimization module. The bio-based polyol adopts a multi-stage vacuum drying process. The first stage of drying removes free water, and the second stage of drying removes bound water. The drying time is dynamically adjusted according to the initial moisture content of the raw material. The isocyanate filtration adopts a multi-stage filtration device, with the filtration accuracy gradually increasing from coarse to fine, and the final filtration accuracy reaching the preset micron level. The mixing of degradation accelerator and functional additives adopts a high-speed mixer. The mixing speed and time are optimized according to the material characteristics to ensure that the mixing uniformity reaches the preset standard, laying the foundation for subsequent reactions and product performance stability.

[0031] This invention also includes a continuous reaction multi-stage control module. The twin-screw extruder is equipped with a feeding section, a melting section, a reaction section, and a homogenization section. The temperature and speed of each section are independently controlled. The feeding section controls the raw material delivery rate, the melting section ensures that the raw material is fully melted, the reaction section promotes the initial polymerization reaction, and the homogenization section ensures that the materials are mixed evenly. The series-connected reactor is equipped with a front section, a middle section, and a rear section. The front section controls the reaction initiation, the middle section maintains the reaction process, and the rear section promotes the termination of the reaction. The stirring speed and reaction time of each section are dynamically adjusted according to the degree of reaction of the prepolymer to ensure that the reaction is sufficient and controllable.

[0032] This invention also includes a post-molding processing module. The granular product after molding is cooled to room temperature by a cooling conveyor belt. The cooling medium adopts a combination of air cooling and water cooling, and the cooling rate is dynamically adjusted according to the product particle size. After cooling, the product is screened by a screening device to remove particles of unqualified size. The screened product is vacuum packaged, and inert gas is filled in during the packaging process to prevent moisture absorption and oxidation. For injection-molded products, stress-relieving annealing treatment is performed. The annealing temperature and time are optimized according to the product structure and thickness to reduce the internal stress of the product and improve the dimensional stability and mechanical properties of the product.

[0033] The following two examples further illustrate specific embodiments of the present invention: Example 1: Continuous Production of Biodegradable Polyurethane for Packaging Materials This embodiment is applied to the production of biodegradable polyurethane films in the food packaging field. The core requirements are that the product has good mechanical strength, controllable degradation rate and dimensional uniformity, and is suitable for large-scale continuous production scenarios. Relying on the whole process collaborative linkage system, it realizes the closed-loop operation of raw material pretreatment, reaction, molding and recycling, ensuring the environmental protection and practicality of packaging materials.

[0034] I. Core Implementation Details Raw material pretreatment module: Plant-based polyols, aliphatic isocyanates, polylactic acid degradation accelerators, and functional additives such as antioxidants and plasticizers are selected. Bio-based polyols undergo a two-stage vacuum drying process. The first-stage drying temperature is adjusted according to the raw material's moisture content to remove free water. The second-stage drying temperature is slightly higher than the first stage to remove bound water, reducing the moisture content to a preset standard after drying. Isocyanates are filtered through a three-stage filtration system, with filtration precision gradually increasing until a preset micron-level precision is achieved, thoroughly removing mechanical impurities. Degradation accelerators and functional additives are pulverized to a preset particle size and fed into a high-speed mixer. The mixing speed and time are set according to the material characteristics to ensure uniform mixing meets the preset standard. After pretreatment, the raw materials are stored in a nitrogen-filled sealed storage tank to prevent moisture absorption and oxidation.

[0035] Metering and Optimization Module: This module uses a combination of a weighing metering pump and an electromagnetic flowmeter to collect real-time flow and mass data for each raw material. Based on the target mechanical properties and degradation rate of the packaging materials, the optimal ratio is determined through the raw material metering optimization module, dynamically adjusting the delivery rate of each raw material. The metered raw materials are then fed into a static mixer equipped with multiple layers of guide vanes to achieve initial uniform mixing before being conveyed to the continuous reaction module, where metering accuracy is maintained within a preset range.

[0036] Continuous Reaction and Temperature Control Module: The continuous reaction module consists of a twin-screw extruder and three series-connected reactors. The twin-screw extruder is divided into a feeding section, a melting section, a reaction section, and a homogenization section. The temperature of each section is independently controlled. The feeding section controls the raw material delivery rate, the melting section ensures the raw material is fully melted, the reaction section promotes the initial polymerization reaction, and the homogenization section ensures uniform mixing of the materials. The series-connected reactors control reaction initiation in the first section, maintain the reaction process in the middle section, and promote reaction termination in the last section. Each section is equipped with a stirring device and temperature and pressure sensors. The temperature and pressure are adjusted through a dynamic reaction temperature control module. During the reaction, an online infrared spectrometer monitors the reaction degree in real time to ensure the formation of high-quality prepolymer.

[0037] Molding and Precision Control Module: Employing extrusion molding technology, the molding unit is equipped with a precision film mold and a trimming device. The extruder die temperature is adjusted according to the prepolymer characteristics. The traction device controls the traction speed via a servo motor. A laser diameter gauge and an infrared thermometer monitor the film thickness and temperature in real time, dynamically adjusting the traction speed and die gap. The trimming device removes irregular edges, ensuring uniform film width and dimensional deviations within a preset range.

[0038] Waste recycling and purification module: Collects film scraps and defective products generated during the production process, crushes them to a preset particle size using a crushing device, and sends them to a melt extruder for remelting. Appropriate amounts of chain extender and degradation regulator are added, along with adsorbent and catalyst. The adsorbent adsorbs impurities and degradation byproducts, while the catalyst promotes secondary reactions of unreacted raw materials. The purification process uses vacuum distillation to remove low-molecular-weight volatiles. After purification, the recovered raw materials are sent to the proportioning and metering module, where they are mixed with new raw materials in a preset ratio and then reintroduced into the production process.

[0039] Quality Inspection and Control System Module: This module collects real-time performance data of the molded film. A gel permeation chromatograph detects molecular weight distribution, a universal testing machine tests tensile strength and elongation at break, a soil burial degradation testing unit monitors degradation rate, and a dynamic mechanical analyzer detects storage modulus and loss modulus. The detection data is fed back to the PLC controller and industrial computer in real time. The control system adjusts the raw material ratio, reaction temperature, molding parameters, and recycling mixing ratio in a coordinated manner. Production data is recorded to create a traceable archive. Remote monitoring is also supported, and alarms are automatically triggered and emergency response plans are pushed out in case of abnormal operating conditions.

[0040] Table 1: Comparison of Production Performance of Packaging Materials Table 1 clearly demonstrates the significant advantages of the system of this invention in packaging material production. Traditional intermittent production suffers from poor coordination between stages, resulting in low production efficiency of only 80 kg / h. Furthermore, batch-to-batch variations in raw materials lead to poor stability in product mechanical properties and degradation rates. Effective waste recycling methods are lacking, with a recovery rate of only 35%. Insufficient product dimensional uniformity also affects packaging performance. The system of this invention, through continuous and collaborative operation throughout the entire process, increases production efficiency to 320 kg / h. Deep optimization of raw material pretreatment and precise control of proportioning ensure stable product performance. The closed-loop waste recycling system achieves a recovery rate of 92%, and the molding precision control module ensures dimensional uniformity, fully meeting the needs of large-scale, high-quality packaging material production.

[0041] Example 2: Continuous Production of Biodegradable Polyurethane for Medical Consumables This embodiment is applied to the production of biodegradable polyurethane for absorbable sutures. The core requirements are that the product has excellent mechanical strength, a precise and controllable degradation rate, and extremely high purity and molding precision, which can meet the strict requirements of the medical field for product stability and safety. Through the fine control of each module of the system, the continuous production of high-value-added biodegradable polyurethane can be achieved.

[0042] I. Core Implementation Details Raw material pretreatment and deep optimization module: Medical-grade bio-based polyols, aromatic isocyanates, hydroxyapatite degradation accelerators, and medical-grade antibacterial agents, toughening agents, and other functional additives are selected. Bio-based polyols undergo multi-stage vacuum drying, with drying time dynamically adjusted based on initial moisture content to ensure the moisture content is reduced to medical-grade standards. Isocyanates are filtered through a four-stage filtration system, achieving a final filtration precision at the preset micron level to remove minute mechanical impurities. Degradation accelerators and functional additives are pulverized to a finer preset particle size and fed into a high-speed mixer. A stepped mixing speed is used, first dispersing at low speed and then homogenizing at high speed to ensure the mixing uniformity meets medical requirements. After pretreatment, the raw materials are stored in a sealed storage tank protected by inert gas, and the purity of the gas in the tank is checked periodically.

[0043] The proportioning, metering, and intelligent control module employs a combination of a high-precision weighing metering pump and an electromagnetic flowmeter, achieving a higher metering frequency than in conventional scenarios. It collects and feeds back raw material flow and quality data in real time. Based on the target mechanical properties and in vivo degradation cycle of the suture, the optimal raw material proportioning module determines the proportions and dynamically adjusts the delivery rate. After initial mixing in a static mixer, the raw materials undergo secondary homogenization in a dynamic mixer to ensure uniform mixing before being delivered to the continuous reaction module, where metering accuracy is controlled within a more stringent preset range.

[0044] Continuous reaction and multi-stage control module: The twin-screw extruder is equipped with a feeding section, a melting section, a reaction section, and a homogenization section. The temperature and speed of each section are independently controlled, and the temperature of the reaction section is precisely controlled according to the requirements of medical-grade prepolymer. The stirring speed and reaction time of the front, middle, and rear sections of the series-connected reactor are dynamically adjusted according to the degree of reaction of the prepolymer. The stirring speed in the front section is lower to promote the initiation of the reaction, the speed in the middle section is moderate to maintain the reaction process, and the speed in the rear section is slightly higher to promote the termination of the reaction. The temperature and pressure of each section are adjusted in real time through the dynamic control module of the reaction temperature, and the degree of reaction is continuously monitored by an online infrared spectrometer to ensure the purity of the prepolymer and the sufficiency of the reaction.

[0045] Molding and Post-processing Module: Employing extrusion molding technology, equipped with medical-grade precision molds and a laser pelletizing device. The extruder die temperature is precisely controlled, the traction device's traction speed is adjusted via a servo control system, and a laser diameter gauge monitors the wire diameter in real time, dynamically adjusting the traction speed and die gap. The pelletizing device cuts to a preset length, ensuring uniform suture diameter and consistent length. After molding, the product is cooled by a cooling conveyor belt using a combination of air and water cooling media, with the cooling rate dynamically adjusted according to the wire diameter. After cooling, it is screened by a sieving device to remove defective products, followed by stress-relief annealing. The annealing temperature and time are optimized based on the suture diameter to reduce internal stress. Finally, it undergoes vacuum packaging, with inert gas filling the packaging process to prevent moisture absorption and oxidation.

[0046] Waste recycling and purification module: Collects suture scraps and defective products generated during the production process, crushes them to a preset particle size using a dedicated crushing device, and sends them to a medical-grade melt extruder for remelting. Medical-grade chain extenders and degradation regulators are added, along with highly selective adsorbents and catalysts. The adsorbents adsorb impurities and degradation byproducts, while the catalysts promote secondary reactions of unreacted raw materials. The purification process uses high-vacuum distillation to remove low-molecular-weight volatiles. After purification, the recycled raw materials reach medical-grade purity standards and are then mixed with new raw materials in a preset ratio before being used in production.

[0047] Quality Inspection and Intelligent Control Module: The quality inspection module collects performance data of molded products and recycled raw materials. Gel permeation chromatography is used for online detection of molecular weight distribution. A universal testing machine tests tensile strength and elongation at break. Seawater degradation and soil burial degradation testing units monitor degradation rates and degradation products under different environments. A dynamic mechanical analyzer detects storage modulus and loss modulus. The detection data is fed back to the intelligent control system in real time. The system integrates machine learning algorithms to establish a mapping model between production parameters and product performance based on historical data, predicting parameter drift trends and proactively adjusting accordingly. It also supports remote monitoring and operation, automatically alarms for abnormal operating conditions and pushes emergency response plans, and records production data to form a complete and traceable archive.

[0048] Table 2: Comparison of Production Performance of Medical Consumables Table 2 data highlights the core value of the system of this invention in the production of medical consumables. Medical consumables have extremely high requirements for product purity, performance stability, and molding precision, which are difficult to meet with traditional intermittent production methods. This results in low product purity, large fluctuations in mechanical properties, inaccurate control of degradation rates, insufficient molding precision, and a waste recycling rate of only 28%, leading to resource waste. The system of this invention, through in-depth optimization of raw material pretreatment, precise control of proportioning and metering, multi-stage control of continuous reaction, and post-molding treatment, enables product purity and molding precision to reach medical-grade standards. Mechanical property stability and controllability of degradation rates are significantly improved, and the closed-loop waste recycling system achieves a high recycling rate of 88%. This ensures the safety and reliability of medical consumables while reducing production costs, meeting the high-quality and environmentally friendly production needs of the medical field.

[0049] refer to Figure 2 This bar chart visually demonstrates the efficiency advantages of the system of this invention throughout the entire production process, with efficiency at each stage far exceeding that of traditional intermittent production. Traditional intermittent production operates independently at each stage, lacking seamless coordination. Raw material pretreatment relies on manual operation, the reaction process needs to be carried out in batches, and waste recycling lacks a systematic process, resulting in low efficiency at each stage. This invention achieves automated graded processing through a deep optimization module for raw material pretreatment; employs combined metering and dynamic adjustment in the proportioning and metering module; ensures efficient reaction progress through multi-stage control and real-time monitoring in the continuous reaction module; precisely controls the molding module to improve processing efficiency; and constructs a closed-loop system for efficient recycling in the waste recycling module. The synergistic interaction of these modules increases efficiency by 2-12 times at each stage from raw material pretreatment to waste recycling, fully meeting the needs of large-scale industrial production and significantly reducing the time cost per unit product.

[0050] refer to Figure 3 The line graph clearly demonstrates the high efficiency and stability of the continuous reaction module of this invention, with the reaction conversion rate steadily increasing over time and rapidly approaching saturation. The rapid increase in conversion rate in the initial stage stems from thorough raw material pretreatment and precise proportioning, laying a solid foundation for the reaction. As the reaction progresses, the temperature and pressure of each stage are adjusted in real time through a dynamic temperature control module, and the reaction process is continuously monitored by an online infrared spectrometer to prevent incomplete or excessive reactions, thus ensuring a steady increase in conversion rate. At 25 minutes, the conversion rate reaches 97% and stabilizes, indicating that the reaction has proceeded sufficiently. Compared to the large fluctuations in conversion rate and incomplete reactions in traditional intermittent reactions, this invention, through multi-stage regulation and real-time monitoring, ensures a controllable and efficient reaction process, resulting in a uniform prepolymer quality, providing a core guarantee for subsequent molding and processing and product performance stability.

[0051] refer to Figure 4The line graph clearly demonstrates the self-optimization capability of the intelligent control system of this invention, showing that product performance remains highly stable even after long-term operation. Traditional production systems are prone to parameter drift and equipment wear and tear with extended operating times, leading to increased fluctuations in product performance. The intelligent control system of this invention integrates machine learning algorithms, establishing a mapping model between production parameters and product performance based on historical production data and quality inspection results. It predicts parameter drift trends and proactively adjusts key indicators such as raw material ratios, reaction temperatures, and molding parameters. Even after 120 hours of operation, product performance fluctuations remain within a low range, without a significant upward trend. This high stability ensures consistent product quality in large-scale continuous production, avoids an increase in defective products due to performance fluctuations, and further improves production efficiency and economic benefits.

[0052] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A continuous production system for biodegradable polyurethane, characterized in that, Includes the following modules: The raw material pretreatment module pretreats bio-based polyols, isocyanates, degradation accelerators, and functional additives respectively; the pretreated raw materials are stored in a sealed storage tank protected by inert gas. The proportioning and metering module uses a combination of a weighing metering pump and an electromagnetic flow meter to collect the flow and mass data of each raw material in real time. Based on the target performance parameters, the proportion of raw materials is adjusted. After the raw materials are initially mixed by a static mixer, they are transported to the continuous reaction module. The continuous reaction module consists of a twin-screw extruder and a series-connected reactor. The twin-screw extruder is equipped with multiple temperature control zones, and the series-connected reactor is equipped with a stirring device and temperature and pressure sensors. The degree of reaction is monitored by an online infrared spectrometer. The molding module receives the prepolymer output from the continuous reaction module and selects either extrusion molding or injection molding process according to product requirements. The extrusion molding unit is equipped with a precision mold and pelletizing device, while the injection molding unit controls the injection pressure and speed through a servo control system. The waste recycling module collects scraps, defective products and reaction residues from the production process. After being crushed by the crushing device, the waste is remelted by the melt extruder, purified and modified by adding chain extenders and degradation regulators, and after removing impurities, it is sent to the proportioning and metering module for recycling. The quality inspection module collects performance data of molded products and recycled raw materials in real time, and uses gel permeation chromatography, universal testing machine and degradation tester for testing. The test results are fed back to the control system module in real time. The control system module uses a PLC controller linked with an industrial computer to receive operating parameters and detection data from each module in real time. It adjusts the raw material ratio, reaction temperature, molding and recycling process parameters through preset algorithms and records production data to form a traceable archive.

2. The continuous production system for biodegradable polyurethane according to claim 1, characterized in that, It also includes a raw material ratio optimization module, which determines the raw material ratio based on the target degradation rate and mechanical properties of biodegradable polyurethane through a multi-objective optimization algorithm. The specific formula is as follows: in For the first The mass ratio coefficient of the raw materials For the first The reactivity weight of the raw materials For the first The influence coefficient of the raw material on mechanical properties Quantification of target mechanical properties For the first The influence coefficient of the raw material on the degradation rate Quantification of the target degradation rate, This represents the total number of types of raw materials.

3. The continuous production system for biodegradable polyurethane according to claim 1, characterized in that, It also includes a dynamic reaction temperature control module, which dynamically adjusts the temperature of each section of the continuous reaction module based on the reaction progress and raw material characteristics. The specific formula is as follows: in For the first The target temperature of the reaction zone. Based on the reaction temperature, For the first The influence coefficient of the reaction process at any given time. For the first The reaction conversion rate at any given time. For the first Pressure influence coefficient of the segment area For the first The difference between the pressure of the section area and the standard pressure.

4. The continuous production system for biodegradable polyurethane according to claim 1, characterized in that, It also includes a waste recycling and purification module, in which adsorbents and catalysts are added during the waste melting process. The adsorbents selectively adsorb impurities and degradation byproducts in the waste, and the catalysts promote the secondary reaction of unreacted raw materials in the waste. The purification process uses vacuum distillation to remove low-molecular-weight volatiles. After purification, the purity of the recycled raw materials reaches the preset standard. The mixing ratio of recycled raw materials and new raw materials is dynamically adjusted according to product performance requirements.

5. The continuous production system for biodegradable polyurethane according to claim 1, characterized in that, It also includes a molding precision control module, which sets up a laser diameter gauge and an infrared thermometer in the extrusion molding unit to monitor the diameter and temperature of the extruded strip in real time, and adjusts the traction speed and pelletizing knife speed through a servo motor; the injection molding unit is equipped with an in-mold pressure sensor to provide real-time feedback on changes in in-mold pressure and dynamically adjust the injection pressure and holding time.

6. The continuous production system for biodegradable polyurethane according to claim 1, characterized in that, It also includes a quality testing module, which sets up soil burial degradation test units and seawater degradation test units for biodegradability to monitor degradation rate and degradation products in real time under different environments; a dynamic mechanical analyzer is added for mechanical properties to test the storage modulus and loss modulus of the product at different temperatures and frequencies; and a gel permeation chromatography is used for online continuous detection of molecular weight distribution, and the detection data generates trend curves in real time. When the data exceeds the preset threshold, the control system module is automatically triggered to adjust the production parameters.

7. The continuous production system for biodegradable polyurethane according to claim 1, characterized in that, It also includes an intelligent control system module that integrates machine learning algorithms. Based on historical production data and quality inspection results, it establishes a mapping model between production parameters and product performance, predicts parameter drift trends in advance, and proactively adjusts key indicators. It also supports remote monitoring and operation, and pushes production status and quality data and equipment operation status in real time through the industrial internet platform. Abnormal operating conditions automatically trigger alarms and push emergency handling plans.

8. The continuous production system for biodegradable polyurethane according to claim 1, characterized in that, It also includes a raw material pretreatment depth optimization module. Bio-based polyols adopt a multi-stage vacuum drying process. The first stage of drying removes free water, and the second stage of drying removes bound water. The drying time is dynamically adjusted according to the initial moisture content of the raw materials. Isocyanate filtration adopts a multi-stage filtration device, and the final filtration accuracy reaches the preset micron level. The mixing of degradation accelerators and functional additives adopts a high-speed mixer, and the mixing speed and time are optimized according to the material characteristics.

9. The continuous production system for biodegradable polyurethane according to claim 1, characterized in that, It also includes a continuous reaction multi-stage control module. The twin-screw extruder is set with a feeding section, a melting section, a reaction section, and a homogenization section, and the temperature and speed of each section are independently controlled. The series reactor is set with a front section, a middle section, and a rear section. The front section controls the reaction initiation, the middle section maintains the reaction process, and the rear section promotes the termination of the reaction. The stirring speed and reaction time of each section are dynamically adjusted according to the degree of reaction of the prepolymer.

10. The continuous production system for biodegradable polyurethane according to claim 1, characterized in that, It also includes a post-molding processing module. The granular products after molding are cooled to room temperature by a cooling conveyor belt. The cooling medium adopts a combination of air cooling and water cooling, and the cooling rate is dynamically adjusted according to the product particle size. After cooling, the products are screened by a screening device to remove particles of unqualified size. The screened products are vacuum packaged, and inert gas is filled in during the packaging process to prevent moisture absorption and oxidation. For injection molded products, stress-relieving annealing treatment is performed. The annealing temperature and time are optimized according to the product structure and thickness.

Images