Continuous forming process for wet multi-layer composites

Abstract

The application discloses a continuous forming process of a wet multi-layer composite material. Nano-level interface treatment technology is adopted to introduce nano-particles or nano-fibers between adjacent layers. Through steps such as nano-sol preparation and spraying, electrostatic spinning to introduce nano-fibers, and functional layer and interface layer compounding, the interlayer bonding force is significantly improved. A roll-to-roll continuous production line is designed, which includes automatic feeding and tension control of the roll material, precise alignment and deviation correction, online quality detection and feedback control, and realizes full-process automation. The drying and curing process is optimized, microwave drying and plasma curing technology are used, and a winding system is integrated, combined with a waste heat recovery and cascade utilization system, to reduce energy consumption. The process effectively solves the problems of poor interlayer bonding force, low production efficiency and high energy consumption of existing multi-layer composite materials, has a wide application prospect in many fields such as aerospace and automobile manufacturing, provides strong support for the progress of composite material forming technology, and greatly promotes the development of related industries.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite material forming process, and particularly relates to a continuous forming process of wet multi-layer composite material. BACKGROUND

[0002] With the rapid development of modern industry, multi-layer composite materials have been increasingly widely used in many fields such as aerospace, automobile manufacturing, electronic equipment and building, because they can integrate the excellent properties of multiple materials. However, in the process of its wide application, the existing multi-layer composite material preparation technology is facing many severe challenges, which seriously restricts the further development and popularization of the technology.

[0003] In terms of interlayer bonding force, traditional multi-layer composite materials generally have serious defects. Due to the lack of effective interlayer reinforcement means, the layers only rely on simple physical contact or weak chemical bonding, resulting in extremely weak interlayer bonding force. In actual use, this weak bonding force is difficult to withstand complex external forces, thus easily causing delamination and peeling. For example, in the aircraft structure parts in the field of aerospace, if the multi-layer composite material delaminates between layers, the overall strength and stability of the structure will be greatly reduced, which poses a serious threat to flight safety; in the field of automobile manufacturing, if the multi-layer composite material used in the automobile body parts peels off between layers, it will not only affect the appearance quality of the automobile, but also reduce its mechanical properties, shorten its service life and increase its maintenance cost.

[0004] Production efficiency and continuity are also the bottleneck of the existing multi-layer composite material preparation technology. Traditional preparation processes often rely on intermittent operation, and seamless connection between various production links is difficult to achieve, requiring a large amount of manual intervention and transfer procedures. This not only leads to a long and complicated production process, but also seriously limits the improvement of production speed. For example, on some traditional multi-layer composite material production lines, after the completion of the compounding of each layer of material, it is necessary to stop the machine for material adjustment, equipment parameter resetting and other operations, so that the whole production process is time-consuming and laborious, and cannot meet the urgent needs of large-scale industrial production for efficient and rapid production. This inefficient production method not only increases the production cost, but also reduces the market competitiveness of enterprises, hindering the widespread popularity of multi-layer composite materials in the market.

[0005] In addition, high energy consumption is another prominent problem of the existing multilayer composite material preparation technology. In the key links of drying and curing, the conventional heating methods such as hot air heating and oven heating are usually used, which have low thermal efficiency. A large amount of heat is lost to the surrounding environment during the transmission process and cannot be effectively utilized. In order to achieve the expected drying and curing effect, a large amount of energy is consumed, which undoubtedly further increases the production cost burden of enterprises. Under the current global background of advocating energy saving and emission reduction and sustainable development, this kind of high energy consumption production mode is obviously contrary to the requirements of the development of the times, and a new low energy consumption preparation process is urgently needed to replace it.

[0006] In summary, the existing multilayer composite material preparation technology has many problems in interlayer bonding force, production efficiency and energy consumption, which seriously limits its wide application in various fields and further development of the industry. Therefore, it has extremely important practical significance and broad market prospects to develop a new continuous forming process of wet multilayer composite material which can effectively solve these problems. SUMMARY

[0007] The present application aims to overcome the defects of the prior art and provide a new continuous forming process of wet multilayer composite material. Through innovative technical means, the interlayer bonding force of multilayer composite material is effectively improved, continuous and efficient production is realized, and energy consumption and production cost are reduced, thereby promoting the wide application of multilayer composite material in many fields and the development of the industry.

[0008] (I) Nano-scale interface treatment

[0009] Preparation and spraying of nanosol

[0010] Selection and pretreatment of inorganic nanoparticles: high-purity silica and alumina nanoparticles prepared by gas phase method are carefully selected, and the particle size is accurately distributed in the range of 20-50 nm. These nanoparticles are placed in a vacuum oven and dried at 120°C for 4 hours to completely remove the surface adsorbed water and significantly improve the compatibility with polymers.

[0011] Selection and preparation of organic high molecular polymer: polyvinyl alcohol (PVA, degree of polymerization 1700, alcoholysis degree 88%) with high acetal (99%) is selected and prepared into a 5wt% aqueous solution. Crosslinking agent glutaraldehyde is added to the PVA solution to promote the curing of the interface layer and enhance the bonding strength and water resistance.

[0012] Preparation and homogenization of nanosol: the pretreated SiO2 and Al2O3 nanoparticles are uniformly mixed in a mass ratio of 1:1, then slowly added to the PVA solution, and the solid content is strictly controlled at 10wt%. Then a high-speed disperser is used to shear at a speed of 10000 rpm for 30 minutes to obtain a uniform and stable nanosol dispersion liquid.

[0013] Automated spray device design and parameter optimization: A six-axis robot arm guided by machine vision and a multi-axis linkage spray gun are used to accurately spray the substrate surface. The optimized spray process parameters are: nozzle diameter 0.3 mm, atomizing gas pressure 0.4 MPa, liquid flow rate 30 mL / min, and gun-to-substrate distance 100 mm. Through this step, a loose and porous nanostructure is formed on the surface of the substrate layer, laying the foundation for the subsequent enhancement of interlayer adhesion.

[0014] Introduction of nanofibers by electrospinning

[0015] Selection and preparation of spinning polymer materials: Nylon 6 chips with a melting point of 225°C are used to prepare a 15wt% solution in hexafluoroisopropanol, and 1wt% cetyltrimethylammonium bromide (CTAB) is added as a conductive additive to effectively improve the spinning performance of the solution.

[0016] Design and improvement of electrospinning equipment: A coaxial electrospinning device is designed, which has a unique structure with an inner layer of spinning solution and an outer layer of high-pressure air. The two work together to form a stable composite jet. A double-ring cylinder collector is also used, with the inner cylinder guiding fiber deposition and the outer cylinder sucking excess fibers, significantly improving the deposition efficiency.

[0017] Optimization and control of electrospinning process parameters: The spinning voltage (15-30 kV), receiving distance (10-20 cm), and solution flow rate (0.5-2 mL / h) are optimized through orthogonal experiments. A high-speed camera is used to monitor the jet carving and fiber morphology in real time, ensuring that the nanofiber layer is uniformly and continuously introduced into the nanostructure, allowing the substrate layer and functional layer to be tightly bonded at the nano-interface, significantly improving the adhesion strength.

[0018] Composite of functional layer and interface layer

[0019] Design and preparation of functional coating: Depending on different application scenarios and requirements, UV-curable acrylate, epoxy resin organic coating systems, or ITO, ZnO inorganic coating systems are selected flexibly. A functional coating with a thickness of 1-10 μm is prepared on a PET base film using a doctor blade method, and after drying and curing, it is used for subsequent composite process with the interface layer.

[0020] Optimization of process parameters for hot pressing composite: A hot roller press composite machine is used for composite operation. By precisely controlling the key parameters of roller pressure (1-5 MPa), temperature (80-130°C), and speed (1-5 m / min), and ensuring the contact time is 5-20 s, the continuous hot pressing composite of the functional layer and the interface layer is realized, further strengthening the interlayer adhesion and overall performance.

[0021] Composite interface performance characterization and evaluation: The microstructure and roughness of the composite interface are observed and analyzed in detail using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Meanwhile, 180° peeling test and tensile shear test are carried out to accurately quantify the interlaminar bonding strength, ensuring that it can reach a high standard of more than 20 N / cm, thereby ensuring the quality and performance stability of the composite material.

[0022] (ii) Roll-to-roll continuous production line design

[0023] Automatic feeding and tension control system of the roll material

[0024] Design and optimization of unwinding device: Electromagnetic powder brake and servo motor work together to realize precise control of unwinding tension, with tension fluctuation strictly limited within ±2%. At the same time, advanced correction device and air inflation shaft are equipped to effectively ensure the coaxiality and axial position stability of the roll material during unwinding, ensuring the continuity and stability of the whole production process.

[0025] Design of guide roller system: The guide roller group is arranged in a unique Archimedes spiral pattern, which cleverly realizes the 90° turning and S-shaped tensioning of the roll material. The surface of the guide roller is coated with polyurethane elastomer with a hardness of Shore A 50-80, which can effectively prevent the roll material from slipping during transmission and avoid damage to the roll material, ensuring the surface quality and integrity of the roll material.

[0026] Synchronous transmission and control scheme: Electronic gear synchronous control system is used to realize the speed synchronization and phase synchronization of the base material roll and the functional layer roll. The speed synchronization error is less than 0.1%, and the phase synchronization error is less than 0.5mm. This high-precision synchronous control can meet the strict requirements of accurate alignment of each layer material in the continuous composite process of multi-layer composite material, effectively improving the quality and production efficiency of the product.

[0027] Design of precise alignment and correction device

[0028] Visual positioning and error compensation algorithm: High-resolution CCD camera with resolution of 50μm / pixel and 75mm telecentric lens are used, and the field of view can fully cover the width of the roll material. A feature matching-based roll edge detection algorithm is developed, with a camera sampling frequency of 100Hz, which can quickly and accurately detect the edge position of the roll material, with a positioning error controlled within ±0.05mm, providing reliable data support for subsequent precise alignment.

[0029] Servo alignment roller design and control: Linear motor is used to drive the alignment roller, which has excellent characteristics such as high response frequency (100 Hz), high displacement resolution (0.1 μm), and large maximum stroke (± 10 mm). Combined with adaptive control algorithm, it can adjust the angle of the alignment roller in real time and accurately according to the edge position information of the coil fed back by vision, effectively compensate the lateral position deviation of the coil, and ensure the accurate alignment between layers of multi-layer composite materials during the compounding process, avoiding product defects caused by inaccurate alignment.

[0030] Infrared correction sensor design: 940 nm infrared LED is selected as the light source, and reflective correction sensor is designed by cleverly pairing silicon photocell and installing on both sides of the coil. The sensor output voltage shows a precise linear relationship with the edge position of the coil, with a sensitivity of up to 0.1 mm and a sampling frequency of 1 kHz, which can monitor the lateral position change of the coil in real time and feedback the signal to the control system in time to take corresponding correction measures, further improving the stability and accuracy of the coil transmission process.

[0031] Online quality detection and feedback control

[0032] Online thickness measurement system design: Advanced laser triangulation thickness measurement principle is adopted, with laser beam spot diameter of only 50 μm, Z-direction repeatability of up to 0.5 μm, and measurement range of 0.05-2 mm, which can accurately measure the thickness change of multi-layer composite materials during production. The measuring head is installed on a linear slide, which can realize efficient reciprocating scanning in the width direction of the coil, with a scanning speed of 1 m / s and a sampling interval of 1 mm, which can comprehensively and quickly obtain the thickness information of the coil, provide basis for timely adjusting the production process parameters, and ensure the consistency and stability of the product thickness.

[0033] Online adhesive strength testing device design: According to ASTM D3359 standard, an automatic scribe is designed to cross-scribe the cured coating, ensuring that the scribe depth can accurately reach the substrate. The 180° peeling method is used to test the adhesive strength, with a 10 N pulling force peeling off the tape from one end, and the critical peeling length is recorded in detail, so as to realize the online detection of the interlayer adhesive strength of multi-layer composite materials. By obtaining the adhesive strength data in time, the possible interlayer bonding problems in the production process can be found in time, and corresponding improvement measures can be taken to ensure the quality and performance reliability of the product.

[0034] Quality data acquisition and statistical analysis: An industrial Ethernet architecture is built to realize real-time acquisition, filtering processing and visual display of data from various quality detection equipment such as thickness gauges and tensile meters, so that the quality data in the production process can be seen at a glance. At the same time, a statistical process control (SPC) module is developed to conduct strict control chart analysis on key quality indicators, which can timely alert and diagnose abnormal working conditions in the production process, so as to take corrective measures in time and ensure that the entire production process is always in a stable and controllable state, effectively improving the product qualification rate and quality stability.

[0035] (III) Optimization of drying and curing process

[0036] Microwave drying technology

[0037] Microwave drying cavity design: A rectangular cavity with WR340 waveguide standard is adopted, with a working frequency of 2.45 GHz and a maximum power of 1.5 kW, and equipped with 3 feed-in ports. The cavity material is 1 mm thick aluminum plate, and the inner wall is plated with a silver layer to significantly improve the Q value, with a plating thickness of not less than 5 μm. This cavity design can provide a stable and efficient microwave field environment, which is conducive to the drying and curing of composite materials.

[0038] Microwave field uniformity optimization: The position and phase of the feed-in port are optimized through professional simulation technology, so that the microwave field along the movement direction of the roll material presents a sinusoidal distribution, with a strict non-uniformity of less than 5%. At the same time, a Teflon mechanical mode stirrer is installed on the inner wall of the cavity, with a rotation speed of 30 rpm, further homogenizing the microwave field distribution, ensuring uniform heating of the composite material during drying and curing, avoiding local overheating or overcooling that may cause product quality problems, and improving the overall quality and performance stability of the product.

[0039] Online moisture monitoring and power control: A near-infrared online moisture meter is used, which has a fast response time (less than 100 ms), excellent repeatability (better than 0.1%) and a wide measurement range (5%-25%), and can accurately monitor the moisture content in the composite material in real time. Based on the fuzzy PID algorithm, a microwave power closed-loop control system is designed to accurately adjust the output power of the magnetron according to the real-time changes in moisture content, realizing intelligent control of the microwave drying process, while ensuring the drying effect, maximizing energy saving and reducing production costs.

[0040] Low-temperature plasma curing

[0041] Plasma generator design: Capacitively coupled plasma source is adopted, the upper electrode adopts a porous and uniformly distributed ring-shaped radio frequency electrode, and the lower electrode adopts a roller type conveying electrode. High-purity graphite is selected as the electrode material, and circulating cooling water is introduced inside to ensure that the temperature does not exceed 80°C during continuous operation. This electrode structure and cooling method can ensure the stable operation of the plasma generator and provide a reliable plasma environment for the curing of composite materials.

[0042] Optimization of working gas and chamber pressure: A mixture of helium and hexafluoroethane is selected as the working gas, with a volume ratio of He:C2F6 being 95:5, and the gas purity being not less than 99.999%. A capillary array flowmeter is used to accurately control the gas inlet amount, and the vacuum pump speed is adjusted to maintain the chamber pressure at 100-500 Pa. By optimizing the composition of the working gas and the chamber pressure, the activity and stability of the plasma can be effectively improved, the curing reaction of the composite material can be promoted, and the curing effect and product quality can be improved.

[0043] RF power supply design and impedance matching: The RF power supply adopts a 13.56 MHz, 5 kW solid-state power amplifier, and is equipped with an automatic impedance matching network. During operation, the plasma voltage and current waveforms in the chamber are monitored in real time, and the LC circuit is adjusted to compensate for impedance changes, so that the reflected power is less than 50 W. This ensures that the RF power supply can efficiently and stably provide energy for the plasma generator, ensuring the smooth progress of the curing process, while reducing energy loss and improving energy utilization.

[0044] Integrated control of drying and curing and winding

[0045] Synchronous transmission control system design: The microwave drying, plasma curing and winding devices are coaxially linked through servo motors to achieve synchronous speed control, ensuring the continuity and stability of the composite material during drying, curing and winding. The drying and curing section is designed with a gantry structure and equipped with a linear motor module, which can flexibly adjust the relative positions of the devices online according to production needs, adapting to the production of multi-layer composite materials of different specifications and different process requirements, and improving the versatility and flexibility of the production line.

[0046] Winding tension closed-loop control: The winding roller is equipped with a magnetic powder brake, which controls the winding tension by precisely adjusting the excitation current, so that the tension fluctuation is less than ±2%. The dancer roll structure is adopted, and the height displacement sensor is used to monitor the winding accumulation amount in real time and feedback to the brake system in time. According to the change of the winding accumulation amount, the winding tension is automatically adjusted to ensure the tightness and flatness of the winding material during winding, avoiding problems such as loose and wrinkled winding material, and improving the winding quality of the product.

[0047] Finished product winding quality detection: CCD camera is used for 360 degree imaging detection of the winding roller, and common defects such as creep, wrinkle and ear-shaped defects of the winding material are focused on, so that quality problems occurring in the winding process can be found in time, and corresponding adjustment and processing can be carried out. At the same time, the first and last sample sections of each finished product are automatically sampled and sent to a mechanical property tester for key mechanical property testing of tensile strength and elongation at break, so as to ensure that the quality of the finished product meets the relevant standards and requirements, and to provide comprehensive and reliable protection for the quality control of the product.

[0048] Waste heat recovery and cascade utilization system

[0049] Microwave power source cooling water waste heat recovery: a plate heat exchanger is connected in series at the end of the magnetron anode cooling water pipeline to form a secondary side circulation system with the fresh water pipeline. By reasonably adjusting the frequency of the circulating pump and the opening degree of the bypass valve, the cooling water temperature can be accurately controlled at 45±2℃, and it can be used for preheating the surface of the base material roll, fully utilizing the waste heat of the microwave power source cooling water, realizing energy recovery and reuse, reducing energy consumption in the production process, improving energy utilization rate, and also helping to improve the initial temperature of the composite material and promote the drying and curing reaction, further improving the production efficiency.

[0050] Energy cascade utilization of plasma electrode cooling system: the plasma electrode cooling circuit is ingeniously divided into high temperature side (60-80℃) and low temperature side (30-40℃), adopting split-range control strategy. The high temperature side is connected with the infrared preheater on the surface of the functional layer roll, which preheats the functional layer roll by using high temperature waste heat, reducing the energy consumption in the subsequent drying and curing process; the low temperature side is used for conditioning cooling and water supply of the circulating water system, realizing the cascade utilization of the energy of the plasma electrode cooling system, maximizing the utilization value of energy, reducing the production cost, and also being beneficial to environmental protection.

[0051] Optimized scheduling of waste heat recovery system: an energy flow network model is built, and complex influencing factors such as process parameters, equipment operating conditions and environmental temperature and humidity are considered. Advanced real-time optimization algorithm is used for intelligent scheduling of the waste heat recovery system, realizing the optimal operation of the waste heat recovery system under the premise of fully meeting the requirements of the multilayer composite material production process, maximizing the energy utilization rate, further reducing the energy consumption and cost in the production process, and making the whole production process more energy-saving, environment-friendly, efficient and economical.

[0052] The beneficial effects of the present application are:

[0053] The continuous forming process of the wet multi-layer composite material of the application effectively solves the problems of poor interlayer bonding force, low production efficiency and high energy consumption in the existing multi-layer composite material technology through innovative nanoscale interface treatment technology, efficient roll-to-roll continuous production line design and optimized drying and curing process, significantly improves the performance and production efficiency of the composite material, reduces the production cost and energy consumption, and has wide application prospect and important industrial value. BRIEF DESCRIPTION OF DRAWINGS

[0054] In order to more clearly illustrate the technical solutions in the application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only the application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0055] Figure 1 It is a schematic diagram of the wet multi-layer composite material production line of the application.

[0056] Figure 2 It is a schematic diagram of the nanoscale interface treatment and quality control system of the application.

[0057] Figure 3 It is a schematic diagram of the microwave drying and plasma curing system of the application.

[0058] Figure 4 It is a schematic diagram of the cross section of the multi-layer composite material structure of the application.

[0059] Figure 5 It is a schematic diagram of the heat recovery and cascade utilization system of the application.

[0060] Figure 6 It is a schematic diagram of the production process of the application. DETAILED DESCRIPTION

[0061] The application will be described in detail below in combination with the drawings and specific embodiments. It should be noted here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments, and other alternative ways can also be used by those skilled in the art to implement them; and the drawings are only used to more specifically describe the embodiments, and are not intended to specifically limit the application.

[0062] It should be noted that the use of terms such as "an embodiment," "an embodiment," "an exemplary embodiment," and "some embodiments" in the specification indicates that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments (whether explicitly described or not) should be within the knowledge of those skilled in the art.

[0063] Generally, terms can be understood at least partly from their use in context. For example, depending at least partly on the context, the term "one or more" as used herein can be used to describe any feature, structure, or characteristic in a singular sense, or a combination of features, structures, or characteristics in a plural sense. Additionally, the term "based on" can be understood not necessarily to convey an exclusive set of factors, but rather, alternatively, depending at least partly on the context, to allow for the presence of other factors that are not necessarily explicitly described.

[0064] I. Nanoscale Interface Treatment

[0065] (I) Preparation and Spraying of Nanosol

[0066] Selection and pretreatment of inorganic nanoparticles

[0067] like Figure 2 As shown, high-purity silica (SiO2) and alumina (Al2O3) nanoparticles prepared by vapor phase method were selected, with a precise particle size distribution between 20-50 nm. To improve compatibility with polymers, these nanoparticles were placed in a vacuum oven and dried continuously at 120°C for 4 hours to effectively remove surface adsorbed water.

[0068] Selection and formulation of organic polymers

[0069] A high-acetal (99%) polyvinyl alcohol (PVA, degree of polymerization 1700, degree of alcoholysis 88%) was carefully selected and prepared into a 5 wt% aqueous solution. Furthermore, an appropriate amount of glutaraldehyde, a crosslinking agent, was added to the PVA solution to promote the curing process of the interfacial layer, significantly improving the bonding strength and water resistance.

[0070] Preparation and homogenization of nanosols

[0071] Pretreated SiO2 and Al2O3 nanoparticles were uniformly mixed at a 1:1 mass ratio and then slowly added to a PVA solution, with the solid content strictly controlled at 10 wt%. A uniform and stable nanosol dispersion was successfully obtained by performing a shearing operation at 10,000 rpm for 30 minutes using a high-speed disperser.

[0072] Design and parameter optimization of automatic spraying device

[0073] As shown in Figure 1 , the six-axis robot guided by machine vision and multi-axis linkage spray gun are used to realize accurate control of the substrate surface spraying process. The optimized spraying process parameters are: nozzle diameter is set to 0.3mm, atomizing gas pressure is stabilized at 0.4MPa, liquid flow is controlled at 30mL / min, and the distance between the spray gun and the substrate is kept at 100mm.

[0074] (II) Introduction of nanofibers by electrospinning

[0075] Selection and preparation of spinning polymer materials

[0076] Nylon 6 chips with a melting point of 225℃ are used to prepare a 15wt% solution of hexafluoroisopropanol. At the same time, 1wt% of cetyltrimethylammonium bromide (CTAB) is added as a conductive additive to effectively improve the spinning performance of the solution.

[0077] Design and improvement of electrospinning equipment

[0078] A unique coaxial electrospinning device is designed, with the inner layer being the spinning solution and the outer layer being high-pressure air, which form a stable composite jet through synergistic action. In addition, a double-ring cylinder collector is used, in which the inner cylinder is responsible for guiding fiber deposition, and the outer cylinder is responsible for sucking excess fibers, thereby greatly improving the deposition efficiency.

[0079] Optimization and control of electrospinning process parameters

[0080] The spinning voltage (15-30kV), receiving distance (10-20cm) and solution flow rate (0.5-2mL / h) are optimized through rigorous orthogonal experiments. High-speed cameras are used to monitor the jet carving and fiber morphology in real time, ensuring that the nanofiber layer has good uniformity and continuity.

[0081] (III) Functional layer and interface layer composite

[0082] Functional coating formula design and preparation

[0083] According to different application requirements, flexible selection of UV-curable acrylate, epoxy resin organic coating system, or ITO, ZnO inorganic coating system. With the help of doctor blade method, the functional coating with a thickness of 1-10μm is carefully prepared on the PET base film, and after drying and curing, it is used for subsequent composite process.

[0084] Optimization of hot pressing composite process parameters

[0085] The advanced thermal roll compounding machine is adopted to realize continuous thermal compounding operation by precisely controlling the key parameters of roll compounding, temperature and speed. The determined optimal compounding conditions are: pressure range between 1-5 MPa, temperature control between 80-130℃, speed maintained between 1-5 m / min, and contact time kept between 5-20 s.

[0086] Performance characterization and evaluation of the compounding interface

[0087] As shown in Figure 2 , the high-resolution scanning electron microscope (SEM) and atomic force microscope (AFM) are used to observe the micro-morphology and roughness of the compounding interface in detail. The 180° peeling test and tensile shear test are carried out to accurately quantify the interlayer bonding strength, ensuring that it can reach a high standard of more than 20 N / cm.

[0088] II. Design of roll-to-roll continuous production line

[0089] (1) Automatic feeding and tension control system of the roll

[0090] Design and optimization of the unwinding device

[0091] As shown in Figure 1 , the combination of electromagnetic powder brake and servo motor is used to precisely control the tension, with the tension fluctuation strictly controlled within ±2%. At the same time, advanced correction devices and inflatable shafts are equipped to effectively ensure the coaxiality and axial position stability of the roll during unwinding.

[0092] Design of the guide roller system

[0093] The guide roller group with unique arrangement of Archimedes spiral is used to cleverly realize the 90° turning of the roll and S-shaped tensioning function. The surface of the guide roller is coated with polyurethane elastomer, with its hardness controlled between Shore A 50-80, effectively preventing the roll from slipping and damage.

[0094] Synchronous transmission and control scheme

[0095] The electronic gear synchronous control system is used to achieve speed synchronization and phase synchronization of the base material roll and functional layer roll. The speed synchronization error is less than 0.1%, and the phase synchronization error is less than 0.5 mm, fully meeting the stringent requirements of high-precision continuous compounding.

[0096] (2) Design of precise alignment and correction device

[0097] Visual positioning and error compensation algorithm

[0098] CCD camera has a resolution of up to 50 μm / pixel, and is equipped with a 75 mm telecentric lens, which can fully cover the width of the web. A feature matching-based web edge detection algorithm is developed, with a camera sampling frequency of up to 100 Hz, and a positioning error controlled within ±0.05 mm.

[0099] Servo alignment roller design and control

[0100] The linear motor drives the alignment roller, with a response frequency of up to 100 Hz, a displacement resolution of 0.1 μm, and a maximum stroke of ±10 mm. An adaptive control algorithm is designed to adjust the angle of the alignment roller in real time based on visual feedback information, and to accurately compensate for the lateral position deviation of the web.

[0101] Infrared correction sensor design

[0102] A 940 nm infrared LED is selected as the light source, and a reflective correction sensor is designed by cleverly pairing a silicon photocell and installing it on both sides of the web. The sensor output voltage shows a precise linear relationship with the edge position of the web, with a sensitivity of up to 0.1 mm and a sampling frequency of 1 kHz.

[0103] (Three) Online quality detection and feedback control

[0104] Online thickness measurement system design

[0105] The laser triangulation method is used to measure the thickness, with a laser beam spot diameter of only 50 μm, a Z-direction repeatability of 0.5 μm, and a measurement range of 0.05-2 mm. The measuring head is installed on a linear slide, which can achieve efficient reciprocating scanning in the width direction of the web, with a scanning speed of 1 m / s and a sampling interval of 1 mm.

[0106] Online adhesive strength testing device design

[0107] Referring to the ASTM D3359 standard, an automatic scribe is carefully designed to make cross-scratches on the cured coating, ensuring that the scribe depth can accurately reach the substrate. The 180° peeling method is used to test the adhesive strength, with a 10 N pulling force to peel off the tape from one end, and the critical peeling length is recorded in detail.

[0108] Quality data acquisition and statistical analysis

[0109] An industrial Ethernet architecture is built to realize real-time acquisition, filtering processing, and visual display of thickness gauge and tensile tester data. A statistical process control (SPC) module is developed to analyze the key quality indicators through rigorous control chart analysis, and to timely warn and diagnose abnormal working conditions.

[0110] Three, drying and curing process optimization

[0111] (One) Microwave drying technology

[0112] Microwave drying cavity design

[0113] like Figure 3 As shown, the rectangular cavity adopts the WR340 waveguide standard, operates at a frequency of 2.45 GHz, has a maximum power of 1.5 kW, and is equipped with three feed inlets. The cavity material is 1 mm thick aluminum plate, with an inner wall electroplated with a silver layer to significantly improve the Q value, and the plating thickness is not less than 5 μm.

[0114] Microwave field uniformity optimization

[0115] By optimizing the feed inlet position and phase through professional simulation, the microwave field exhibits a sinusoidal distribution along the direction of roll material movement, with a non-uniformity strictly less than 5%. A Teflon mechanical stirrer with a rotation speed of 30 rpm is installed on the inner wall of the cavity to further homogenize the microwave field distribution.

[0116] Online moisture monitoring and power control

[0117] A near-infrared online moisture meter is used, with a response time of less than 100ms, a repeatability better than 0.1%, and a measurement range of 5%-25%. A microwave power closed-loop control system is designed based on a fuzzy PID algorithm to adjust the magnetron output power in real time according to the moisture content.

[0118] (II) Low-temperature plasma curing

[0119] Plasma generator design

[0120] A capacitively coupled plasma source is used, with a porous, evenly distributed ring-shaped radio frequency electrode as the upper electrode and a roller-type transport electrode as the lower electrode. High-purity graphite is selected as the electrode material, and circulating cooling water is circulated inside to ensure that the temperature does not exceed 80°C during continuous operation.

[0121] Working gas and chamber pressure optimization

[0122] A mixture of helium and hexafluoroethane is selected as the working medium, with a He:C₂F₆ volume ratio of 95:5 and a gas purity of not less than 99.999%. A capillary array flow meter is used to precisely control the gas intake, and the vacuum pump speed is adjusted to maintain the chamber pressure at 100-500 Pa.

[0123] RF power supply design and impedance matching

[0124] The RF power supply uses a 13.56MHz, 5kW solid-state power amplifier equipped with an automatic impedance matching network. It monitors the plasma voltage and current waveforms within the chamber in real time, adjusting the LC circuit to compensate for impedance changes, resulting in a reflected power of less than 50W.

[0125] (III) Integrated Control of Drying, Curing and Winding

[0126] Synchronous transmission control system design

[0127] The microwave drying, plasma curing and winding device are coaxially linked by servo motors to realize synchronous speed control. The gantry structure is arranged in the drying and curing section, and a linear motor module is arranged to adjust the relative position of each device.

[0128] Winding tension closed-loop control

[0129] The winding roller is equipped with a magnetic powder brake, and the winding tension is controlled by adjusting the excitation current, and the tension fluctuation is less than ±2%. The wobble roller structure is adopted, and the height displacement sensor is used to monitor the winding material accumulation in real time and feedback to the brake system.

[0130] Finished product winding quality detection

[0131] The winding roller is detected by a 360° imaging detection of a CCD camera, focusing on defects such as creep, wrinkling and ear-shaped defects. The first and last sample sections of each finished product are automatically sampled and sent to a mechanical property tester for tensile strength and elongation at break tests.

[0132] (4) Waste heat recovery and cascade utilization system

[0133] Microwave power source cooling water waste heat recovery

[0134] As shown in Figure 5 , the magnetron anode cooling water pipeline is connected in series with a plate heat exchanger at the end, and a secondary side circulation system is formed with the fresh water pipeline. By adjusting the circulating pump frequency and bypass valve opening, the cooling water temperature is accurately controlled at 45±2℃, which is used for preheating the surface of the base material roll.

[0135] Energy cascade utilization of plasma electrode cooling system

[0136] The plasma electrode cooling circuit is divided into high temperature side (60-80℃) and low temperature side (30-40℃), and a split range control strategy is adopted. The high temperature side is connected to the infrared preheater on the surface of the functional layer roll, and the low temperature side is used for conditioning cooling and water supply of the circulating water system.

[0137] Optimized scheduling of waste heat recovery system

[0138] An energy flow network model is built, and various influencing factors such as process parameters, equipment operating conditions and environmental temperature and humidity are considered. Real-time optimization algorithm is used to schedule the waste heat recovery system to maximize energy utilization while fully meeting process requirements.

[0139] Example 1:

[0140] Preparation and application of wet multi-layer composite material

[0141] Objective: To prepare a wet multi-layer composite material with excellent interfacial bonding strength and water resistance, and test its application performance in electronic product shells.

[0142] Implementation steps:

[0143] Nanosol preparation:

[0144] As Figure 2 shown, SiO2 and Al2O3 nanoparticles with a particle size of 20-50 nm prepared by the gas phase method were selected and placed in a vacuum oven with a temperature setting of 120°C for continuous drying for 4 hours to remove surface-adsorbed water.

[0145] A 5wt% PVA aqueous solution was mixed with a crosslinking agent, glutaraldehyde, at a mass ratio of 1:1 to prepare a PVA solution.

[0146] A uniform SiO2 / Al2O3 / PVA nanosol was obtained by shearing at a speed of 10000 rpm for 30 minutes using a high-speed disperser.

[0147] Electrospinning process:

[0148] Nylon 6 chips were dissolved in a hexafluoroisopropanol solution with a concentration of 15wt%, and 1wt% CTAB was added.

[0149] Spinning was performed using a self-designed coaxial electrospinning device with a spinning voltage of 25kV, a receiving distance of 15cm, and a solution flow rate of 1mL / h. A high-speed camera was used to monitor the fiber morphology in real time to ensure uniform and continuous fiber layers.

[0150] Functional layer composite:

[0151] UV-curable acrylate was selected as the functional coating material, and a doctor blade method was used to coat it on the PET base film with a thickness control of 5μm.

[0152] The composite operation was performed using a hot press composite machine with a temperature setting of 100°C, a pressure setting of 3MPa, a composite speed of 3m / min, and a contact time of 10s.

[0153] Performance testing:

[0154] As Figure 2 shown, scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to observe the micro-morphology of the composite interface and analyze its roughness and interfacial bonding strength.

[0155] A 180° peeling test was performed, and the interlayer bonding strength was measured to be 25N / cm, meeting the high strength requirement.

[0156] Application effect:

[0157] The wet multi-layer composite material is successfully applied to the outer shell of electronic products, with excellent water resistance and mechanical strength, effectively improving the durability and impact resistance of the shell.

[0158] Example 2:

[0159] Design and application of roll-to-roll continuous production line

[0160] Objective: To design and optimize a roll-to-roll continuous production line for mass production of nanocomposites, ensuring efficient and stable production.

[0161] Implementation steps:

[0162] Automatic feeding and tension control:

[0163] As shown in Figure 1 , the electromagnetic powder brake and servo motor combination is used to control the tension of the roll material, ensuring that the tension fluctuation is strictly controlled within ±2%.

[0164] The gas expansion shaft and deviation correction device are used to maintain the coaxiality of the roll material, ensuring the uniformity of the substrate surface.

[0165] Guiding roller system design:

[0166] The Archimedes spiral type guiding roller group is used to prevent the roll material from slipping or being damaged during turning and tensioning. The roller group surface is coated with polyurethane elastomer, with a hardness control of Shore A60, increasing the wear resistance and contact performance of the roller group with the roll material.

[0167] Precise alignment and deviation correction:

[0168] Equipped with a CCD camera, the edge position of the roll material is detected in real time through a feature matching algorithm, with a positioning error controlled within ±0.05mm, ensuring the accurate alignment of the roll material.

[0169] The servo alignment roller driven by a linear motor adjusts the alignment roller angle in real time combined with visual feedback information, ensuring that the lateral deviation of the roll material is within a reasonable range.

[0170] Online quality detection:

[0171] A thickness gauge using laser triangulation method is used, with a measurement range of 0.05-2mm and an accuracy of 0.5μm, ensuring the uniformity of the thickness of each layer of coating.

[0172] An online adhesive strength testing device is set up to perform peeling tests according to ASTM D3359 standard, ensuring that the interlayer bonding strength of each batch of products reaches more than 20N / cm.

[0173] Application effect:

[0174] Through the optimized roll-to-roll production line, high-precision continuous production is realized, the product shows excellent performance in quality control, the production efficiency is improved by 30%, and the coating performance meets the requirements of high strength, water resistance, etc., suitable for large-scale production of nanocomposites.

[0175] Example 3:

[0176] Optimization and application of microwave drying process

[0177] Objective: To optimize the microwave drying process and improve the drying efficiency and uniformity of wet multi-layer composite materials.

[0178] Implementation steps:

[0179] Microwave drying cavity design:

[0180] As shown in Figure 3 , the design adopts a rectangular cavity with WR340 waveguide standard, the working frequency is 2.45GHz, and the maximum power is 1.5kW. The cavity material is 1mm thick aluminum plate, and the inner wall is plated with silver layer to improve the Q value.

[0181] Equipped with 3 feed-inlets to ensure uniform distribution of microwave energy and improve drying efficiency.

[0182] Microwave drying process control:

[0183] The coated substrate is passed through the microwave drying cavity, the temperature in the cavity is set to 80℃, and the stable working environment is maintained through the automatic temperature control system.

[0184] The microwave power is set to 1kW, and the drying time is controlled within 3 minutes to ensure uniform drying of the coating without overheating.

[0185] The mechanical strength of the dried composite material is tested, and the interlayer bonding strength is measured to be 22N / cm, meeting the requirements.

[0186] Use an infrared thermal imager to monitor the drying process to ensure that the material surface temperature is uniform and has no fluctuations.

[0187] Application effect:

[0188] The optimization of microwave drying process significantly improves the drying efficiency, reduces the drying time, and reduces the energy consumption, ensuring the quality stability of wet multi-layer composite materials after drying.

[0189] The present application encompasses any alternatives, modifications, equivalent methods and solutions made within the spirit and scope of the present application. In order to make the public thoroughly understand the present application, specific details are explained in the following preferred embodiments of the present application, and the present application can be completely understood without the description of these details by those skilled in the art. In addition, in order to avoid unnecessary confusion to the essence of the present application, well-known methods, processes, procedures, elements and circuits, etc. are not described in detail.

[0190] The above description is only the preferred embodiments of the present application, and it should be pointed out that for ordinary skilled in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should be considered as the protection scope of the present application.

[0191] The present application encompasses any alternatives, modifications, equivalent methods and solutions made within the spirit and scope of the present application. In order to make the public thoroughly understand the present application, specific details are explained in the following preferred embodiments of the present application, and the present application can be completely understood without the description of these details by those skilled in the art. In addition, in order to avoid unnecessary confusion to the essence of the present application, well-known methods, processes, procedures, elements and circuits, etc. are not described in detail.

[0192] The above description is only the preferred embodiments of the present application, and it should be pointed out that for ordinary skilled in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should be considered as the protection scope of the present application.

Claims

1. A continuous molding process for wet-process multilayer composite materials, characterized in that, The process includes the following steps: A layer of nano-sol is sprayed onto the surface of a substrate. The nano-sol includes high-purity silica and alumina nanoparticles with a particle size range of 20-50 nm. It is mixed with a polyvinyl alcohol solution and then homogenized. Nanofibers are introduced into the nanosol using electrospinning technology to form a nanofiber layer, wherein the nanofibers are composed of nylon 6 and a hexadecyltrimethylammonium bromide solution; In the nanostructure, a functional layer is composited with a substrate layer by a hot-pressing process. The functional layer is a coating that is either UV-cured or epoxy-cured. After drying and curing, a multi-layered composite material is formed for continuous production.

2. The process according to claim 1, wherein the nanosol is a mixture of SiO2 and Al2O3 nanoparticles in a 1:1 mass ratio, and the solid content of the nanosol is controlled at 10 wt%.

3. The process according to claim 1, wherein the concentration of the PVA solution is 5 wt%, and the crosslinking agent glutaraldehyde is added to the solution to promote the curing of the interface layer.

4. The process according to claim 1, wherein the electrospinning step uses a 15 wt% hexafluoroisopropanol solution, and 1 wt% CTAB is added to the solution as a conductive additive.

5. The process according to claim 1, wherein the spraying process employs a six-axis robotic arm guided by machine vision and a multi-axis linkage spray gun, the nozzle diameter is 0.3 mm, the atomizing air pressure is 0.4 MPa, the liquid flow rate is 30 mL / min, and the distance between the spray gun and the substrate is 100 mm.

6. The process according to claim 1, wherein the hot-pressing composite process is carried out at a temperature range of 80-130℃, a pressure range of 1-5MPa, a vehicle speed of 1-5m / min, and a contact time of 5-20s.

7. The process according to claim 1, wherein the interface layer of the composite material is analyzed for morphology using high-resolution scanning electron microscopy and atomic force microscopy, and the interlayer bonding strength in the peel test reaches 20 N / cm or higher.

8. The continuous molding process for wet-process multilayer composite materials according to claim 1, characterized in that, This process is achieved through a roll-to-roll continuous forming production line, which includes: The automatic feed and tension control system uses an electromagnetic powder brake and a servo motor to control the tension fluctuation within ±2%, and is equipped with a correction device and an air shaft. The guide roller system uses Archimedes spiral rollers and is coated with polyurethane elastomer to prevent damage to the roll material; The visual positioning and error compensation system uses a CCD camera and feature matching algorithm to control the positioning error within ±0.05mm. The online quality inspection system, including a laser thickness gauge and an automated adhesive strength testing device, collects data in real time and performs statistical analysis via an industrial Ethernet architecture.

9. The process according to claim 8, wherein the online thickness measurement system adopts laser triangulation, has a measurement range of 0.05-2mm, a repeatability of 0.5μm, a scanning speed of 1m / s, and a sampling interval of 1mm.

10. The process according to claim 8, wherein the online adhesive strength testing device adopts the 180° peel method and applies a tensile force of 10N during the test.

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