Wide-temperature-range shape memory high-resilience hot melt film preparation system

Abstract

The invention discloses a wide-temperature-range shape memory high-resilience hot melt film preparation system, and relates to the technical field of hot melt film preparation, the wide-temperature-range shape memory high-resilience hot melt film preparation system comprises a melting plasticizing unit and a winding unit, and further comprises an ultrasonic standing wave molecular chain dynamic interlocking extrusion module, a piezoelectric ceramic array stress coding calendering module and a photo-thermal response interlocking module which are sequentially connected in series; according to the invention, ultrasonic standing wave molecular chain dynamic interlocking, piezoelectric ceramic array gradient stress coding, photo-thermal response interlocking type and real-time feedback closed loop technologies are utilized to solve the problems that the existing system depends on a multi-component formula and later training, and temperature range and bidirectional memory splitting and resilience and fatigue resistance cannot be achieved at the same time; continuous precise response and bidirectional reversible memory circulation of the membrane material in the whole temperature range of-50 DEG C to 150 DEG C are achieved, the membrane material has excellent high resilience and fatigue resistance, batch consistency and stability are improved, the membrane material can flexibly adapt to multi-scene requirements, and production efficiency is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of hot melt film preparation technology, specifically a wide-temperature-range shape memory high-resilience hot melt film preparation system. Background Technology

[0002] Wide-temperature-range shape memory high-resilience hot melt films are in high demand in fields such as smart wearables and aerospace. Existing preparation systems consist of modules such as melt extrusion and calendering. The core is to optimize the material formulation and eliminate preparation defects. By copolymerization modification and nano-doping, the temperature range can be broadened, while the process can be optimized to eliminate stress residues and ensure shape memory and resilience performance.

[0003] However, existing systems cannot achieve wide-temperature-range shape memory, bidirectional memory response, and high resilience through their own process control and coordination. They can only rely on external means such as material formulation optimization and post-training to compensate, resulting in low efficiency, high cost, and insufficient stability. Specifically: the stress control module of the fabrication system can only achieve stress elimination, not stress empowerment; the temperature range adaptation of shape memory depends on a single triggering mechanism, and the wide temperature range characteristics can only be achieved through material formulation adjustments. At the same time, the bidirectional shape memory function can only be obtained through repeated thermal training in the later stages. The fabrication system itself cannot directly endow the film material with bidirectional memory response capabilities during the molding process, resulting in the temperature range adaptability and bidirectional memory of the film material being disconnected and unable to be optimized synergistically; technicians generally believe that molecular chain entanglement is a static structure that is fixed after fabrication and only affects mechanical strength, and is unrelated to the temperature response mode of shape memory. This means that the fabrication system does not consider achieving precise memory response in different temperature ranges by controlling the gradient distribution of the molecular chain entanglement state, thus limiting the wide temperature range to coverage of multiple temperature points and making it difficult to achieve bidirectional reversible temperature memory cycling.

[0004] Therefore, a wide-temperature-range shape memory high-resilience hot melt film preparation system is provided to overcome the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a wide-temperature-range shape memory high-resilience hot melt film preparation system to solve the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the present invention provides a wide temperature range shape memory high resilience hot melt film preparation system, including a melting and plasticizing unit and a winding unit, and further including an ultrasonic standing wave molecular chain dynamic interlocking extrusion module, a piezoelectric ceramic array stress coding calendering module, and a photothermal response interlocking module connected in series. The ultrasonic standing wave molecular chain dynamic interlocking extrusion module is used to construct a three-dimensional network structure with alternating rigid interlocking points and flexible entanglement regions, which is used for the precise binding of molecular chain entanglement and temperature response range. The piezoelectric ceramic array stress-encoded calendering module is used to store the recovery energy required for bidirectional memory in the form of gradient stress signals from the surface to the middle layer in a three-dimensional network structure, thus completing a one-to-one correspondence between stress and temperature range; The photothermal response interlocking module activates the synergistic response of gradient stress and molecular chain interlocking network through gradient photothermal field, and uses core-shell shape memory microspheres to construct multi-temperature response nodes for wide-temperature-range bidirectional reversible memory cycling.

[0007] Furthermore, the ultrasonic standing wave molecular chain dynamic interlocking extrusion module includes a cylindrical one-piece molded die head, with an annular ultrasonic transducer built into the middle of the die head. The ultrasonic transducer is fastened to the pre-reserved installation groove on the inner wall of the die head by M4 bolts, with a coaxiality error of ≤0.1mm with the flow channel axis. An elastic flow-limiting valve is installed at the die head outlet. The valve material is fluororubber and it is connected to the die head by three micro springs evenly distributed in the circumference.

[0008] Furthermore, the raw materials for the ultrasonic standing wave molecular chain dynamic interlocking extrusion module include polylactic acid-polyethylene oxide copolymer and ultrasonically responsive boron nitride nanosheets. The number average molecular weight of the copolymer is 50,000 to 80,000, and the amount of nanosheets added is 1 wt% to 3 wt%. The double bonds on the surface are modified by silane coupling agent KH570. The raw materials are premixed in a high-speed mixer at a mixing speed of 1500 r / min for 30 min.

[0009] Furthermore, the piezoelectric ceramic array stress-encoded calendering module includes a double-roll symmetrical calendering structure. Both the upper and lower rolls are hollow rolls made of No. 45 steel, with a diameter of 200 mm and a length of 500 mm. The surface roughness of the rolls is Ra≤0.8μm, and array-type mounting holes are reserved inside the rolls. Each roll is evenly divided into three independent coding zones along the axial direction, corresponding to the low-temperature response zone, the medium-temperature response zone, and the high-temperature response zone, respectively. The zones are separated by a 2 mm thick polytetrafluoroethylene plate for insulation. Each coding zone is arranged with 30 to 70 PZT-5H type piezoelectric ceramic units, which are fixed in the mounting holes of the rolls with epoxy resin. The top of the unit is 1 mm away from the elastic layer on the roll surface.

[0010] Furthermore, the piezoelectric ceramic array stress-encoded rolling module also includes a dynamic wedge stress depth adjustment component and a real-time stress feedback calibration unit; the dynamic wedge component includes miniature wedge-shaped springs that correspond one-to-one with the piezoelectric ceramic units; the elastic layer of the roll surface is made of silicone rubber, with a deformation space of 0.3mm to 0.5mm reserved at the contact point with the wedge-shaped springs; the real-time stress feedback calibration unit includes a BF120-3AA type miniature strain gauge embedded in the elastic layer of the roll surface, which is connected to an S7-200SMART type programmable controller through a data acquisition card for stress closed-loop adjustment.

[0011] Furthermore, the photothermal response interlocking module includes a three-dimensional photothermal grid channel, with three sets of infrared laser grids arranged inside along the thickness direction of the film material; each set of grids contains 10 laser emitters with wavelengths of 808nm, 1064nm, and 1550nm, forming a gradient photothermal field of the surface photothermal zone, the middle photothermal zone, and the core photothermal zone.

[0012] Furthermore, 5wt% to 8wt% of core-shell shape memory microspheres are added to the raw materials of the photothermal response interlocking module. The core material of the microspheres is polycaprolactone, and the shell material is polymethyl methacrylate. An EMP-100 low-frequency electromagnetic pulse generator is arranged at the end of the photothermal channel, with a distance of 10mm to 20mm between the generator and the membrane material.

[0013] Furthermore, the melt plasticizing unit is a twin-screw extruder with a barrel temperature of 170℃~200℃ and a screw speed of 100r / min~150r / min; the ultrasonic standing wave molecular chain dynamic interlocking extrusion module has an extrusion line speed of 0.5m / min~1m / min and a preform film thickness of 0.2mm~0.6mm; the piezoelectric ceramic array stress coding calendering module has a speed ratio of 1.2~1.5 and a calender film thickness of 0.08mm~0.2mm; the photothermal response interlocking molding module and the cooling roller group both have a line speed of 0.5m / min~1m / min, a cooling roller surface temperature of 25℃~35℃, and a winding tension of 5N~10N.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. Without relying on multi-component formulation layering and subsequent thermal training, the membrane material is directly endowed with a wide temperature range bidirectional memory response capability through the molding process, avoiding the problems of low efficiency and high cost of existing technologies, and significantly improving production efficiency.

[0015] 2. Achieve a precise one-to-one correspondence between stress and temperature range, achieving continuous and accurate response across the entire temperature range from -50℃ to 150℃. This solves the core pain point of existing technologies where temperature range adaptability and bidirectional memory are mutually exclusive, enabling wide-range bidirectional reversible memory cycling.

[0016] 3. The synergistic effect of gradient stress field, molecular chain interlocking network and asynchronous phase transition of core-shell microspheres enables the membrane material to have both excellent high resilience and fatigue resistance, breaking through the limitation of existing technologies where the two cannot be achieved simultaneously.

[0017] 4. The real-time stress feedback closed-loop control mechanism significantly improves the batch performance consistency of membrane materials; it also has a stress self-compensation function, which can restore the memory performance without additional processing after stress loss caused by external force, and its stability is significantly better than the existing system.

[0018] 5. The memory resilience can be precisely controlled through a proprietary formula, which can flexibly adapt to the different application needs of flexible smart wearables and rigid aerospace applications, making it more widely applicable. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the wide-temperature-range shape memory high-resilience hot melt film preparation system of the present invention. 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] Please see Figure 1 The present invention provides a technical solution: See Figure 1 An example of a wide-temperature-range shape memory high-resilience hot melt film preparation system is shown below: This system, through dynamic interlocking, energy storage, and multi-field activation, is composed of an ultrasonic standing wave molecular chain dynamic interlocking extrusion module, a piezoelectric ceramic array stress-encoded calendering module, and a photothermal response interlocking molding module connected in series, with each module working in concert.

[0022] I. Ultrasonic Standing Wave Molecular Chain Dynamic Interlocking Extrusion Module: A three-dimensional network structure alternating between rigid interlocking points and flexible entanglement regions is constructed to provide a stable microscopic anchoring basis for subsequent stress coding, thereby achieving precise binding between molecular chain entanglement and temperature response range.

[0023] 1. Mold head structure: The mold head is a cylindrical one-piece mold head made of 304 stainless steel, with a length of 80mm and a flow channel diameter of 12mm. The mold head has a built-in annular ultrasonic transducer, model USR-2040, with a working frequency of 20kHz~40kHz and a rated power of 500W~1500W. The transducer is fastened to the reserved mounting groove on the inner wall of the mold head by M4 bolts. The coaxiality error with the flow channel axis is ≤0.1mm, ensuring the formation of an alternating energy field of nodes and antinodes along the length of the flow channel. 2. Raw material formulation: Shape memory copolymer, selected from polylactic acid-polyethylene oxide copolymer, with a number average molecular weight of 50,000-80,000, with 1wt%-3wt% of ultrasonically responsive boron nitride nanosheets, particle size of 50nm-100nm, and surface modified with silane coupling agent KH570 for double bonds. The nanosheets and copolymer are premixed in a high-speed mixer and then fed into an extruder; speed 1500r / min, mixing time 30min; 3. Extrusion control: When the molten material (extruder barrel temperature 170℃~200℃, screw speed 100r / min~150r / min) flows through the die head channel, the high-energy region at the antinodes induces dynamic cross-linking between the double bonds and molecular chains on the surface of boron nitride nanosheets, forming rigid interlocking points with a diameter of 100nm~200nm; the low-energy region at the nodes retains the flexible entanglement of molecular chains, with an entanglement density of 1 / 3 to 1 / 2 that at the antinodes; To precisely control the spatial distribution density of rigid interlocking points (a core microscopic parameter for subsequent stress coding anchoring), it is necessary to establish a quantitative relationship between ultrasonic standing wave parameters, nanosheet addition amount, and rigid interlocking point density. This ensures accurate matching between the rigid interlocking points and the flexible entanglement network with subsequent zoned stress coding, leading to the derivation of the formula for calculating rigid interlocking point density. Formula (1): ; In the formula: The density of rigid interlocking points at antinodes is the core microscopic anchoring parameter for subsequent stress coding; The reactivity coefficient of ultrasonically responsive nanosheets is related to the degree of double bond modification on the nanosheet surface; : Mass fraction of ultrasonically responsive boron nitride nanosheets; : Rated power of ultrasonic transducer; : Operating frequency of the ultrasonic transducer; The ultrasonic standing wave energy threshold, i.e., the minimum energy required to induce cross-linking between nanosheets and molecular chains, is determined by the type of copolymer; for example, the energy required for polylactic acid-polyethylene oxide copolymers is... =10 4 W·kHz; : Melting temperature of the copolymer, polylactic acid-polyethylene copolymer =170℃; Extruder barrel temperature; Temperature influence coefficient: Characterizes the degree to which temperature deviates from the melting temperature on the crosslinking reaction.

[0024] 4. Homogenization treatment: An elastic flow-limiting valve (made of fluororubber, 3mm thick) is installed at the die outlet. The valve is connected to the die through three micro springs evenly distributed in the circumference. The spring elasticity coefficient is 5N / mm. This ensures that the valve vibrates synchronously at the working frequency of the ultrasonic transducer, eliminates the radial velocity difference of the extruded melt, and ensures that the rigid interlocking points and flexible entanglement area network are evenly distributed. 5. Pre-forming parameters: The thickness of the extruded film is controlled at 0.2mm~0.6mm, and the extrusion line speed is 0.5m / min~1m / min.

[0025] II. Piezoelectric ceramic array stress-encoded rolling module: By using partitioned independent encoding, dynamic wedge components, and real-time stress feedback units, the recovery energy required for bidirectional memory is precisely stored in the network of rigid interlocking points and flexible entanglement zones in the form of gradient stress signals from the surface to the middle layer. This completely replaces the later thermal training and achieves a one-to-one correspondence between stress and temperature range.

[0026] 1. Calendering Roll Structure: The calendering roll adopts a double-roll symmetrical calendering structure. Both the upper and lower rolls are hollow rolls made of No. 45 steel, with a diameter of 200mm and a length of 500mm. The surface roughness of the rolls is Ra≤0.8μm. The roll body has pre-reserved array-type mounting holes with a diameter of 8mm, a depth of 20mm, and a spacing of 10mm×10mm, for mounting piezoelectric ceramic units. 2. Independently encoded piezoelectric array in different zones: Zoning: Each roller is evenly divided into 3 independent coding zones along the axial direction. Each zone is 150mm long and the zones are separated by 2mm thick polytetrafluoroethylene (PTFE) sheets to prevent voltage crosstalk. These zones correspond to the low temperature response zone (-50℃~0℃), medium temperature response zone (0℃~100℃), and high temperature response zone (100℃~150℃) of the film material, respectively. Piezoelectric ceramic unit: 30 to 70 piezoelectric ceramic units (model: PZT-5H) are arranged in each coding area. The unit is fixed in the roller mounting hole by epoxy resin, and the top of the unit is 1mm away from the elastic layer of the roller surface. Since the core of zoned stress coding is to achieve a one-to-one correspondence between temperature ranges, stress signals, and molecular chain structures, it is necessary to determine the molecular chain entanglement density (derived from the ultrasonic standing wave module) for different temperature ranges. (Derived), calculate the pulse voltage of the corresponding encoding region to ensure that the stress signal can be accurately stored in the interlocking network, and derive the formula for calculating the partition pulse voltage: Formula (2): ; In the formula: : No. Pulse voltage of the piezoelectric ceramic unit in each coding area =1, 2, 3 correspond to the low temperature, medium temperature, and high temperature response regions, respectively, with values ​​of 500~800V (forward) and -300~-500V (reverse). The stress-voltage conversion coefficient is determined by the material of the elastic layer on the roller surface; the corresponding elastic layer is silicone rubber. =0.02V·mm / N; : No. The target stress corresponding to each coding zone is 5-8 MPa in the low temperature zone, 8-12 MPa in the medium temperature zone, and 12-15 MPa in the high temperature zone. The piezoelectric constant of a piezoelectric ceramic element; The relative permittivity of the piezoelectric ceramic unit, corresponding to PZT-5H. =3000; Thickness of the piezoelectric ceramic unit; : No. The density of rigid interlocking points corresponding to each coding zone is calculated by formula (1): 0.01-0.015 points / μm³ in the low temperature zone, 0.015-0.025 points / μm³ in the medium temperature zone, and 0.025-0.03 points / μm³ in the high temperature zone. : Referencing the density of rigid interlocking points, the average density in the medium temperature region is taken as 0.02 points / μm³.

[0027] Voltage control: Each encoding area is equipped with an independent pulse signal generator (model SG3525), which outputs a dedicated bidirectional pulse voltage signal calculated by formula (2): Low temperature response range: forward voltage 500V, reverse voltage -300V, pulse frequency 10Hz, duty cycle 50%; Medium temperature response range: forward voltage 650V, reverse voltage -400V, pulse frequency 15Hz, duty cycle 50%; High-temperature response range: forward voltage 800V, reverse voltage -500V, pulse frequency 20Hz, duty cycle 50%; Matching relationship: The voltage signal is precisely matched with the ultrasonic interlocking network; the low temperature response region corresponds to the low entanglement flexible region, and the high temperature response region corresponds to the high entanglement rigid region, realizing a one-to-one correspondence between temperature range, stress signal, and molecular chain structure.

[0028] 3. Dynamic wedge stress depth adjustment component: Wedge structure: A micro wedge-shaped spring (made of 65Mn spring steel, thickness 0.5mm~1mm, wedge angle 3°~5°, surface galvanized for rust prevention) is embedded between each piezoelectric ceramic unit and the elastic layer of the roller surface. The spring corresponds one-to-one with the piezoelectric ceramic unit, and the wedge tip faces the direction of film material travel. Elastic layer design: The elastic layer on the roller surface is made of silicone rubber (2mm to 4mm thick), which is fixed to the roller surface through a vulcanization process. A deformation space of 0.3mm to 0.5mm is reserved at the contact point between the elastic layer and the wedge-shaped spring sheet. The core function of the dynamic wedge is to convert the expansion and contraction of the piezoelectric ceramic into a gradient stress depth within the film material. It is necessary to establish a quantitative relationship between the wedge angle, the thickness of the spring sheet, the piezoelectric elongation, and the stress depth to ensure that the stress can extend from the surface layer to the middle layer. The formula for calculating the stress depth is then derived. Formula (3): ; In the formula: The stress transmission depth inside the membrane material is 0–15 μm; 0–5 μm for the surface layer and 5–15 μm for the middle layer. The expansion and contraction (mm) of the piezoelectric ceramic unit is controlled by voltage and ranges from 0.1 to 0.3 mm. The wedge angle of the miniature wedge-shaped shrapnel is 3 to 5 degrees. The thickness of the miniature wedge-shaped spring is 0.5–1 mm. Reference spring thickness, taken as 0.75mm; The elastic modulus of a wedge-shaped spring sheet, corresponding to 65Mn spring steel. =206 GPa; : The elastic modulus of the roller surface elastic layer, corresponding to silicone rubber =5MPa.

[0029] Stress depth control: When the piezoelectric ceramic unit is stretched by a positive voltage, it pushes the wedge tip of the wedge-shaped spring out, and the elastic layer bulges locally. According to formula (3), the stress depth extends from the surface layer (0μm~5μm) of the film to the middle layer (5μm~15μm). When it is contracted by a reverse voltage, the wedge tail of the wedge-shaped spring retracts, the elastic layer returns to flatness, and the stress is concentrated on the surface layer (0μm~5μm). By combining the wedge angle and the thickness of the spring, a gradient stress field from the compressive stress of the surface layer to the tensile stress of the middle layer is formed, ensuring that the bidirectional memory recovery force is transmitted from the inside of the film to the outside.

[0030] 4. Real-time stress feedback calibration unit: Strain gauge installation: Inside the elastic layer of the roller surface, corresponding to the position of each piezoelectric ceramic unit, a mounting groove with a depth of 0.3mm to 0.5mm is reserved, and a micro strain gauge (model BF120-3AA) is embedded. The strain gauge is fixed with silicone glue, and the lead wire is connected to the signal acquisition device through the reserved wire hole inside the roller body. Closed-loop control: Strain gauges detect the stress transfer effect when the membrane material is in contact with the elastic layer in real time. The voltage of the piezoelectric ceramic unit needs to be corrected based on the deviation between the detected stress and the target stress. The stress feedback voltage correction formula is then derived. Formula (4): ; In the formula: The revised version of the first... Pulse voltage of each piezoelectric ceramic unit in the coding area; The initial pulse voltage before correction is calculated using formula (2); : Feedback adjustment coefficient, characterizing the sensitivity of stress deviation to voltage correction; The strain gauge detected the first Actual stress in each coding area; : No. The target stress of each coding region is consistent with that in formula (2).

[0031] The strain gauge detection signal is transmitted to the programmable controller (S7-200SMART) via a data acquisition card (model NI-DAQmx) and closed-loop regulation is performed according to formula (4): When the detected stress is lower than the set threshold (5MPa~10MPa), the controller automatically increases the voltage of the corresponding piezoelectric ceramic unit by 10V~20V; When the detected stress exceeds the set threshold (15MPa~20MPa), the controller automatically reduces the voltage of the corresponding piezoelectric ceramic unit by 5V~10V; Synchronization control: The closed-loop adjustment frequency is kept consistent with the pulse voltage frequency (10Hz~20Hz) to ensure the real-time accuracy of stress coding; 5. Calendering parameters: The calendering roller speed is matched with the extrusion line speed (0.5m / min~1m / min), the speed ratio is 1.2~1.5, the calendering pressure is indirectly controlled by the elongation of the piezoelectric ceramic unit (elongation 0.1mm~0.3mm), and finally the film material is calendered to the target thickness of 0.08mm~0.2mm.

[0032] It should be noted here that: The independent coding of partitions breaks through the industry convention of uniform stress across the entire domain. Through formula (2), the stress signal is accurately bound to the temperature response range and the molecular chain entanglement density, thus solving the positioning problem of molecular chain entanglement and temperature range adaptation. The dynamic wedge assembly is a simple mechanical structure that can be processed by conventional stamping process. The stress depth can be quantitatively controlled by formula (3) without the need for complicated instruments. The real-time stress feedback closed loop transforms passively applied stress into active calibration stress through formula (4), and the correction amount is correlated with the initial encoded voltage and stress deviation, forming a synergistic control logic that is adapted to the interlocked structure of the molecular chain, thus solving the problem of uneven stress distribution in the existing technology.

[0033] III. Photothermal Response Interlocking Module: By activating the synergistic response of gradient stress and molecular chain interlocking network through gradient photothermal field activation, multi-temperature response nodes are constructed using core-shell shape memory microspheres to achieve wide-temperature-range bidirectional reversible memory cycling, while optimizing rebound performance.

[0034] 1. Three-dimensional photothermal grid channel: The main body of the channel is made of stainless steel (1000mm in length, 500mm in width, and 50mm in height). Three sets of infrared laser grids are arranged inside along the thickness direction of the film material. Each set of grids contains 10 laser emitters (power 100W–500W, wavelengths 808nm, 1064nm, and 1550nm respectively). The laser emitter spacing is 20mm–30mm, and the spot diameter is 5mm–10mm, forming a gradient photothermal field. Surface photothermal zone (corresponding to the surface of the film material): 808nm laser, temperature 60℃~80℃; Middle layer photothermal zone (corresponding to the middle layer of the film material): 1064nm laser, temperature 100℃~120℃; Core layer photothermal zone (corresponding to the core layer of the film material): 1550nm laser, temperature 80℃~100℃; 2. Addition of core-shell shape memory microspheres: 5wt% to 8wt% of core-shell shape memory microspheres (core material is polycaprolactone, melting point 55℃ to 60℃; shell material is polymethyl methacrylate, glass transition temperature 105℃ to 110℃; particle size 500nm to 800nm) are added to the raw materials. The microspheres and copolymers are uniformly dispersed in the extruder with a dispersion of ≥95%. To ensure that core-shell microspheres achieve asynchronous phase transition (shell softening, core crystallization) in a gradient photothermal field, it is necessary to quantify the relationship between laser parameters, temperature, and microsphere activation efficiency, and derive the formula for the asynchronous phase transition activation efficiency of core-shell microspheres: Formula (5): ; In the formula: The asynchronous phase transition activation efficiency of the core-shell microspheres is ≥90% to ensure that the microspheres are effectively embedded in the gradient stress field. Laser wavelength adaptation coefficient, which is related to the core-shell material of the microspheres; The emission power of the laser at the corresponding wavelength, ranging from 100 to 500W; Laser wavelength, with values ​​of 808, 1064, and 1550 nm; Laser spot area, spot diameter 5-10mm corresponds to =19.6~78.5mm²; The particle size of the core-shell microspheres is 0.5–0.8 μm. : No. The temperature of each solar thermal zone, =1, 2, 3 correspond to the surface layer, middle layer, and core layer, respectively, with values ​​ranging from 60 to 120℃; Microsphere Phase transition temperature (°C). =1 represents the glass transition temperature of the shell material (105~110℃). =2 represents the melting point of the core material (55-60℃); Reference transformation temperature: The average value of the transformation temperatures of the shell material and the core material is taken as 82.5℃. The volume fraction of core-shell microspheres is calculated from the mass fraction; 5–8 wt% corresponds to… =4~7%.

[0035] 3. Asynchronous phase change activation: When the membrane material passes through the photothermal channel at a speed of 0.5m / min to 1m / min, the activation efficiency of the core-shell microspheres in the gradient photothermal field, calculated by formula (5), undergoes an asynchronous phase change: the shell material softens in the high-temperature zone of the middle layer, and the core material crystallizes in the low-temperature zone of the surface / core layer, embedding the molecular chain interlocking network corresponding to the gradient stress field to form multiple temperature response nodes; 4. Electromagnetic optimization: At the end of the photothermal channel, a set of low-frequency electromagnetic pulse generators (model EMP-100) is arranged. The distance between the generator and the membrane material is 10mm to 20mm. The electromagnetic pulse induces the redistribution of surface charge of microspheres, enhances the interaction between microspheres and molecular chains, and optimizes the resilience performance and temperature range adaptation accuracy. 5. Cooling and shaping: The film material after photothermal and electromagnetic treatment enters the cooling roller group (roller surface temperature 25℃~35℃, linear speed consistent with photothermal channel) for cooling and shaping, and finally is wound up by the winding machine (winding tension 5N~10N).

[0036] III. System Workflow: 1. Raw material pretreatment: Polylactic acid-polyethylene oxide copolymer, ultrasonically responsive boron nitride nanosheets, and core-shell shape memory microspheres are mixed at a mass ratio of 90:2:8 and put into a high-speed mixer (1500r / min, 30min) for premixing to obtain a uniform mixed raw material; 2. Melting and plasticizing: The mixed raw materials are fed into a twin-screw extruder, and the barrel temperature is set to 170℃~200℃ and the screw speed is set to 100r / min~150r / min. After melting and plasticizing, a uniform melt is formed. 3. Dynamic interlocking extrusion: The melt enters the ultrasonic standing wave molecular chain dynamic interlocking extrusion module, the ultrasonic transducer is turned on (20kHz~40kHz, 500W~1500W), the density of rigid interlocking points is calculated according to formula (1), and a network of rigid interlocking points and flexible entanglement areas is formed under the action of the energy field of nodes and antinodes. The extrusion is carried out at a linear speed of 0.5m / min~1m / min to obtain a preformed film with a thickness of 0.2mm~0.6mm. 4. Gradient stress coding calendering: The preformed film enters the piezoelectric ceramic array stress coding calendering module, calculates the initial pulse voltage of the three coding areas according to formula (2), and turns on the pulse signal generator to output the corresponding voltage; The dynamic wedge assembly expands and contracts with the piezoelectric ceramic unit, and the stress depth is adjusted according to formula (3) to form a gradient stress field from the surface to the middle layer; The real-time stress feedback unit is activated, and the actual stress is detected by the strain gauge. The voltage is corrected according to formula (4) to ensure accurate stress transmission. Calendering at a speed ratio of 1.2 to 1.5 yields a calendered film with a thickness of 0.08 mm to 0.2 mm. 5. Photothermal and electromagnetic shaping: The calendered film enters the photothermal response interlocking module, and the laser power and temperature are set according to formula (5). Three sets of infrared laser grids and low-frequency electromagnetic pulse generators are turned on, and the response nodes are activated under the gradient photothermal field and electromagnetic action. 6. Cooling and winding: After being shaped by the cooling roller group at 25℃~35℃, it is wound up by the winding machine (5N~10N tension) to obtain the finished product of wide temperature range shape memory high elasticity hot melt film.

[0037] Summarize: The finished membrane material completely solves the core pain points of existing technologies. It can achieve a wide temperature range response without relying on the superposition of multi-component formulations. It achieves continuous and accurate response across the entire temperature range by virtue of the temperature adaptability of the microstructure itself. At the same time, it has excellent bidirectional memory performance and does not require post-thermal training, significantly improving production efficiency. Its high resilience stability far exceeds that of existing technologies. Meanwhile, the memory recovery force in different temperature ranges can be precisely controlled by a dedicated formula, which can adapt to the differentiated needs of flexible smart wearables and rigid aerospace fixation. Through real-time stress feedback closed-loop control, the batch performance consistency is greatly improved. It has a stress self-compensation function, and the memory performance can be restored without additional processing after stress loss caused by external force. Moreover, through the synergistic effect of gradient stress and molecular chain interlocking network, it breaks through the limitation of existing technologies that fatigue resistance and resilience performance cannot be achieved simultaneously.

Claims

1. A wide-temperature-range shape memory high-resilience hot melt film preparation system, comprising a melt plasticizing unit and a winding unit, characterized in that, It also includes an ultrasonic standing wave molecular chain dynamic interlocking extrusion module, a piezoelectric ceramic array stress-encoded calendering module, and a photothermal response interlocking module connected in series. The ultrasonic standing wave molecular chain dynamic interlocking extrusion module is used to construct a three-dimensional network structure with alternating rigid interlocking points and flexible entanglement regions, which is used for the precise binding of molecular chain entanglement and temperature response range. The piezoelectric ceramic array stress-encoded calendering module is used to store the recovery energy required for bidirectional memory in the form of gradient stress signals from the surface to the middle layer in a three-dimensional network structure, thus completing a one-to-one correspondence between stress and temperature range; The photothermal response interlocking module activates the synergistic response of gradient stress and molecular chain interlocking network through gradient photothermal field, and uses core-shell shape memory microspheres to construct multi-temperature response nodes for wide-temperature-range bidirectional reversible memory cycling.

2. The wide-temperature-range shape memory high-resilience hot melt film preparation system as described in claim 1, characterized in that: The ultrasonic standing wave molecular chain dynamic interlocking extrusion module includes a cylindrical one-piece die head with an annular ultrasonic transducer built into the middle of the die head. The ultrasonic transducer is fastened to the pre-reserved installation groove on the inner wall of the die head by M4 bolts, with a coaxiality error of ≤0.1mm with the flow channel axis. An elastic flow-limiting valve is installed at the die head outlet. The valve material is fluororubber and it is connected to the die head by three micro springs evenly distributed in the circumference.

3. The wide-temperature-range shape memory high-resilience hot melt film preparation system as described in claim 2, characterized in that: The raw materials for the ultrasonic standing wave molecular chain dynamic interlocking extrusion module include polylactic acid-polyethylene oxide copolymer and ultrasonically responsive boron nitride nanosheets. The number average molecular weight of the copolymer is 50,000 to 80,000, and the amount of nanosheets added is 1 wt% to 3 wt%. The double bonds on the surface are modified by silane coupling agent KH570. The raw materials are premixed in a high-speed mixer at a mixing speed of 1500 r / min for 30 min.

4. The wide-temperature-range shape memory high-resilience hot melt film preparation system as described in claim 1, characterized in that: The piezoelectric ceramic array stress-encoded calendering module includes a double-roll symmetrical calendering structure. Both the upper and lower rolls are hollow rolls made of No. 45 steel, with a diameter of 200 mm and a length of 500 mm. The surface roughness of the rolls is Ra≤0.8μm, and array-type mounting holes are reserved inside the rolls. Each roll is evenly divided into three independent coding zones along the axial direction, corresponding to the low-temperature response zone, the medium-temperature response zone, and the high-temperature response zone, respectively. The zones are separated by a 2 mm thick polytetrafluoroethylene (PTFE) plate for insulation. Each coding zone is arranged with 30 to 70 PZT-5H type piezoelectric ceramic units, which are fixed in the mounting holes of the rolls with epoxy resin. The top of the unit is 1 mm away from the elastic layer on the roll surface.

5. The wide-temperature-range shape memory high-resilience hot melt film preparation system as described in claim 4, characterized in that: The piezoelectric ceramic array stress-encoded calendering module also includes a dynamic wedge stress depth adjustment component and a real-time stress feedback calibration unit; the dynamic wedge component includes micro wedge-shaped springs that correspond one-to-one with the piezoelectric ceramic units; the elastic layer of the roller surface is made of silicone rubber, with a deformation space of 0.3mm to 0.5mm reserved at the contact point with the wedge-shaped springs; The real-time stress feedback calibration unit includes a BF120-3AA type micro strain gauge embedded in the elastic layer of the roller surface, which is connected to an S7-200SMART type programmable controller via a data acquisition card for stress closed-loop adjustment.

6. The wide-temperature-range shape memory high-resilience hot melt film preparation system as described in claim 1, characterized in that: The photothermal response interlocking module includes a three-dimensional photothermal grid channel, with three sets of infrared laser grids arranged along the thickness direction of the film material inside; each set of grids contains 10 laser emitters with wavelengths of 808nm, 1064nm and 1550nm, forming a gradient photothermal field of surface photothermal zone, middle photothermal zone and core photothermal zone.

7. The wide-temperature-range shape memory high-resilience hot melt film preparation system as described in claim 6, characterized in that: The raw material of the photothermal response interlocking module contains 5wt% to 8wt% of core-shell shape memory microspheres. The core material of the microspheres is polycaprolactone, and the shell material is polymethyl methacrylate. An EMP-100 low-frequency electromagnetic pulse generator is arranged at the end of the photothermal channel, with a distance of 10mm to 20mm between the generator and the membrane material.

8. The wide-temperature-range shape memory high-resilience hot melt film preparation system as described in claim 1, characterized in that: The melt plasticizing unit is a twin-screw extruder with a barrel temperature of 170℃~200℃ and a screw speed of 100r / min~150r / min; the ultrasonic standing wave molecular chain dynamic interlocking extrusion module has an extrusion line speed of 0.5m / min~1m / min and a preform film thickness of 0.2mm~0.6mm; the piezoelectric ceramic array stress coding calendering module has a speed ratio of 1.2~1.5 and a calender film thickness of 0.08mm~0.2mm; the photothermal response interlocking molding module and the cooling roller group both have a line speed of 0.5m / min~1m / min, a cooling roller surface temperature of 25℃~35℃, and a winding tension of 5N~10N.

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