Low temperature thermoplastic panel composition, low temperature thermoplastic panel, low temperature thermoplastic composite panel and ankle orthosis

Abstract

The application relates to the technical field of high polymer materials, and provides a low-temperature thermoplastic plate composition, a low-temperature thermoplastic plate, a low-temperature thermoplastic composite plate and an ankle orthosis, wherein the low-temperature thermoplastic plate composition comprises, in percentage by mass, a base 70-99%, a filler 1-25%, a compatilizer 0-5% and a crosslinking agent 0-5%; the filler comprises one or more of talcum powder, modified nanoparticles and modified fibers. The low-temperature thermoplastic plate prepared by using the composition has high strength, low plastic temperature and good shape memory performance; the low-temperature thermoplastic composite plate also has good piezoelectric performance, can realize real-time sensing of the stress state of the ankle, realizes dynamic monitoring of the rehabilitation state, meets the performance requirements of the ankle orthosis in aspects of bearing, fixing and intelligent rehabilitation monitoring and the like, and can be applied to the field of active rehabilitation instruments.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to low-temperature thermoplastic board compositions, low-temperature thermoplastic boards, low-temperature thermoplastic composite boards, and foot and ankle orthotics. Background Technology

[0002] The foot and ankle are among the most weight-bearing joints in the human body and are also prone to sports injuries. Foot and ankle injuries often require the use of orthoses for immobilization, support, and rehabilitation. Ankle-foot orthoses (AFOs) are commonly used rehabilitation aids, widely applied in the correction and rehabilitation of foot and ankle fractures, ligament injuries, foot and ankle instability, flat feet, high arches, and foot drop after stroke.

[0003] Low-temperature thermoplastic sheets are a new type of orthotic material, primarily based on polycaprolactone. This biodegradable material softens at 60°C and can be repeatedly thermoplasticized. Compared to traditional plaster, low-temperature thermoplastic sheets offer advantages such as light weight, ease of handling, good adhesion, reshaping capability, and X-ray permeability. They are currently widely used in the personalized customization of foot and ankle orthoses.

[0004] However, existing low-temperature thermoplastic sheets have the following shortcomings:

[0005] (1) Insufficient strength: The foot and ankle need to bear the full weight of the human body in daily activities and generate complex mechanical responses; existing low-temperature thermoplastic plates are prone to deformation or even breakage when bearing large loads, and their firmness is insufficient, making it difficult to meet the strength requirements of foot and ankle orthotics.

[0006] (2) Interface bonding problem: It is a common strategy to reinforce materials with inorganic fillers such as inorganic fibers and particles. However, the interface bonding strength between inorganic fillers and polycaprolactone matrix is ​​low. After a period of use, the filler and matrix are prone to debonding, which affects the service life and safety of the orthotics.

[0007] (3) Biocompatibility issues: Some inorganic fillers have poor biocompatibility. Long-term contact with human skin may cause skin lesions such as contact dermatitis, affecting the patient's wearing comfort and compliance.

[0008] (4) Single function: The existing low-temperature thermoplastic board only has passive fixation and support functions, and cannot realize real-time monitoring and feedback of the patient's rehabilitation status, and cannot meet the needs of precise rehabilitation and intelligent rehabilitation.

[0009] Furthermore, compared to traditional passive rehabilitation devices (such as plaster casts and splints), the core advantage of active rehabilitation devices lies in their ability to achieve dynamic intervention and closed-loop feedback, representing an important direction for the development of rehabilitation medicine. In foot and ankle rehabilitation, real-time monitoring of parameters such as gait, pressure distribution, and range of motion is crucial for developing personalized rehabilitation plans and evaluating rehabilitation outcomes.

[0010] Piezoelectric materials can convert mechanical stress into electrical signals. Combining these materials with low-temperature thermoplastic plates enables orthoses to sense their own stress state, providing a technological foundation for closed-loop feedback in active rehabilitation devices. Furthermore, the integration of piezoelectric coating technology can significantly enhance the intelligence level of foot and ankle orthoses.

[0011] Therefore, providing a low-temperature thermoplastic composite board with high strength, low molding temperature, good shape memory function and piezoelectric properties is of great significance for its application in foot and ankle orthotics. Summary of the Invention

[0012] The technical problem solved by the present invention is to provide a low-temperature thermoplastic sheet and a low-temperature thermoplastic composite sheet. The low-temperature thermoplastic sheet has high strength, low molding temperature and good shape memory function. The low-temperature thermoplastic composite sheet provided in this application also has excellent piezoelectric properties.

[0013] In view of this, this application provides a low-temperature thermoplastic sheet composition, comprising, by weight percentage: 70%~99% matrix, 1%~25% filler, 0~5% compatibilizer, and 0~5% crosslinking agent;

[0014] The filler includes one or more of talc, modified nanoparticles, and modified fibers.

[0015] In some specific embodiments, the talc powder has a mesh size of 800-10000 mesh; and / or, the modified nanoparticles are selected from one or more of silane coupling agent modified zinc oxide, silane coupling agent modified silica, silane coupling agent modified titanium dioxide, and silane coupling agent modified alumina; and / or, the modified fiber is selected from one or more of silane coupling agent modified basalt fiber, silane coupling agent modified glass fiber, and silane coupling agent modified carbon fiber.

[0016] In some specific embodiments, the compatibilizer includes one or more of epoxy functional group polymers, isocyanates, and acid anhydrides, and / or the amount of the compatibilizer is 0.1% to 3%; and / or the crosslinking agent includes one or more of triallyl isocyanurate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, benzoyl peroxide, and dicumyl peroxide, and / or the amount of the crosslinking agent is 0.1% to 3%.

[0017] This application also provides a low-temperature thermoplastic sheet, which is prepared from the low-temperature thermoplastic sheet composition described in the above-described scheme.

[0018] This application also provides a low-temperature thermoplastic composite board, including the low-temperature thermoplastic board described in the above-mentioned solution.

[0019] In some specific embodiments, the low-temperature thermoplastic composite board further includes a piezoelectric functional layer and an encapsulation layer. The piezoelectric functional layer is formed on the surface of the low-temperature thermoplastic board, and the encapsulation layer is formed on the surface of the piezoelectric functional layer.

[0020] In some specific embodiments, the raw materials for preparing the piezoelectric functional layer include lead-free piezoelectric materials, tackifying polymers, and dispersing solvents, and / or the raw materials for preparing the encapsulation layer include piezoelectric materials and polymers.

[0021] In some specific embodiments, in the piezoelectric functional layer, the lead-free piezoelectric material includes one or more of barium titanate, potassium sodium niobate, and sodium bismuth titanate; the tackifying polymer includes one or more of polycaprolactone, thermoplastic polyurethane, and polyvinyl butyral; and the dispersing solvent includes one or more of dichloromethane, acetone, tetrahydrofuran, and isopropanol; and / or, in the encapsulation layer, the piezoelectric material includes one or more of barium titanate, potassium sodium niobate, and sodium bismuth titanate; and the polymer includes one or more of polycaprolactone, thermoplastic polyurethane, ethylene-vinyl acetate copolymer, polyolefin elastomer, polyvinylidene fluoride, and polydimethylsiloxane.

[0022] In some specific embodiments, electrodes are disposed on the encapsulation layer, and the material of the electrodes is selected from conductive silver paste or copper foil.

[0023] This application also provides a foot and ankle orthosis, including the low-temperature thermoplastic composite plate described above.

[0024] This application provides a low-temperature thermoplastic board, which is prepared from a low-temperature thermoplastic board composition including filler, crosslinking agent, compatibilizer and matrix. Through the filler and crosslinking agent, the mechanical strength of the thermoplastic board is significantly improved, with an elastic modulus of over 900 MPa, an elongation at break of over 160%, and a flexural modulus of over 800 MPa. It can withstand the complex mechanical loads of the foot and ankle in daily activities and meet the strength requirements of foot and ankle orthoses. At the same time, it maintains a low molding temperature (60~65℃), which is convenient for medical staff to shape on-site and for patients to adjust themselves. It has good shape memory properties, with a fixation rate of 82%~85% and a recovery rate of 78%~85%, which can adapt to the needs of shape changes during foot and ankle rehabilitation. Furthermore, the filler is modified with a silane coupling agent, which effectively improves the interfacial adhesion strength between the filler and the matrix, avoids debonding during use, and extends the service life of the orthosis.

[0025] This application also provides a low-temperature thermoplastic composite board, which endows the low-temperature thermoplastic board with piezoelectric properties by setting a piezoelectric functional layer and an encapsulation layer on the surface of the low-temperature thermoplastic board. It can sense the pressure and stress distribution of the foot and ankle orthosis in real time, providing data support for rehabilitation status monitoring and effect evaluation, and is expected to be applied in the field of active rehabilitation devices. Furthermore, it uses lead-free piezoelectric materials, which have good biocompatibility and no toxic side effects on the human body. The preparation method has a simplified process flow, is easy to operate, and has great feasibility for industrial promotion. Detailed Implementation

[0026] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0027] In view of the aforementioned problems of insufficient strength, interfacial adhesion, biocompatibility, and limited functionality in existing low-temperature thermoplastic sheets, this application provides a low-temperature thermoplastic sheet that, by introducing specific matrix materials and fillers, achieves high mechanical strength, elastic modulus, elongation at break, and low molding temperature. Furthermore, the introduction of a crosslinking agent into the system improves the shape memory performance of the low-temperature thermoplastic sheet. Simultaneously, this application also provides a low-temperature thermoplastic composite sheet, wherein the introduction of a piezoelectric functional layer and an encapsulation layer facilitates the monitoring and effect evaluation of the rehabilitation state, and exhibits good biocompatibility and no toxic side effects on the human body. Specifically, the embodiments of this invention first disclose a low-temperature thermoplastic sheet composition, comprising, by weight percentage: 70%~99% matrix, 1%~25% filler, 0~5% compatibilizer, and 0~5% crosslinking agent;

[0028] The filler includes one or more of talc, modified nanoparticles, and modified fibers.

[0029] In the low-temperature thermoplastic board composition, the mass content of the matrix is ​​70%~99%, in some specific embodiments the mass content of the matrix is ​​70%~95%, in some specific embodiments the mass content of the matrix is ​​75%~90%, in some specific embodiments the mass content of the matrix is ​​75%~85%, and in some specific embodiments the mass content of the matrix is ​​78%~80%.

[0030] In some specific embodiments, the matrix includes one or more of polycaprolactone, vinyl acetate, polyurethane, polyoxymethylene, acrylonitrile-butadiene-styrene copolymer (ABS), styrene-acrylonitrile copolymer (SAN), and polylactic acid. In some specific embodiments, the matrix is ​​selected from one or more of polycaprolactone, vinyl acetate, polyurethane, polyoxymethylene, acrylonitrile-butadiene-styrene copolymer (ABS), styrene-acrylonitrile copolymer (SAN), and polylactic acid. In some specific embodiments, the matrix is ​​polycaprolactone and ABS. Taking polycaprolactone (PCL) as an example, the matrix in the low-temperature thermoplastic sheet composition has a low melting point (approximately 60°C), flexible molecular chains, and an extremely low glass transition temperature (Tg) (approximately -60°C). This determines that it can soften in low-temperature hot water (60~70°C), giving the low-temperature thermoplastic sheet excellent low plasticity temperature. Simultaneously, PCL melts when heated above its melting point, becoming soft and malleable.

[0031] In this application, the mass content of the filler is 1% to 25%. In some specific embodiments, the mass content of the filler is 1% to 20%. In some specific embodiments, the mass content of the filler is 5% to 18%. In some specific embodiments, the mass content of the filler is 8% to 15%. In some specific embodiments, the mass content of the filler is 10% to 12%.

[0032] In some specific embodiments, the filler includes one or more of talc, modified nanoparticles, and modified fibers. In some specific embodiments, the filler is selected from one or more of talc, modified nanoparticles, and modified fibers. In some specific embodiments, the filler is selected from one or more of modified nanoparticles and modified fibers. The modified nanoparticles are selected from one or more of silane coupling agent-modified zinc oxide, silane coupling agent-modified silica, silane coupling agent-modified titanium dioxide, and silane coupling agent-modified alumina. The modified fibers are selected from one or more of silane coupling agent-modified basalt fiber, silane coupling agent-modified glass fiber, and silane coupling agent-modified carbon fiber. In some specific embodiments, the filler is selected from silane coupling agent-modified glass fiber. In some specific embodiments, the talc has a mesh size of 800-10000 mesh; in some specific embodiments, the talc has a mesh size of 1000-8000 mesh; and in some specific embodiments, the talc has a mesh size of 1500-4000 mesh.

[0033] In some specific embodiments, the preparation method of the silane coupling agent modified filler includes the following steps:

[0034] The silane coupling agent is dissolved in an ethanol-water solution to hydrolyze it into silanol groups, which are then mixed with nanoparticles or fibers for modification.

[0035] In the above preparation method, in some specific embodiments, the pH value of the ethanol-water solution is 6-7.

[0036] In the above preparation method, there is no special limitation on the type of silane coupling agent, which can be any suitable silane coupling agent known to those skilled in the art. In some specific embodiments, the silane coupling agent is KH-550.

[0037] In some specific embodiments, the compatibilizer includes one or more of epoxy functional group polymers, isocyanates, and acid anhydrides. In some specific embodiments, the compatibilizer is selected from acid anhydrides. In some specific embodiments, the compatibilizer is selected from maleic anhydride-grafted ABS. In some specific embodiments, the mass content of the compatibilizer is 0%~5%, in some specific embodiments, the mass content of the compatibilizer is 0.1%~3%, in some specific embodiments, the mass content of the compatibilizer is 0.3%~2.5%, and in some specific embodiments, the mass content of the compatibilizer is 0.5%~2%. The addition of the above compatibilizer can improve the interfacial adhesion of the matrix, stabilize the phase morphology, and improve the mechanical properties.

[0038] In some specific embodiments, the crosslinking agent includes one or more of triallyl isocyanurate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, benzoyl peroxide, and dicumyl peroxide. In some specific embodiments, the crosslinking agent is selected from one or more of triallyl isocyanurate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, benzoyl peroxide, and dicumyl peroxide. In some specific embodiments, the crosslinking agent is selected from trimethylolpropane triacrylate. In some specific embodiments, the mass content of the crosslinking agent is 0%~5%; in some specific embodiments, the mass content of the crosslinking agent is 0.1%~3%; in some specific embodiments, the mass content of the crosslinking agent is 0.5%~2%; and in some specific embodiments, the mass content of the crosslinking agent is 0.8%~1.6%. The cross-linking network formed by the aforementioned cross-linking agent restricts the disordered slippage of molecular chains. After cooling, the crystalline region reforms and locks in the temporary shape. Upon reheating, the resilience provided by the cross-linking network structure drives the molecular chains back to their initial state. The cross-linking network ensures that the low-temperature thermoplastic sheet can still return to its initial state after multiple heating-cooling cycles, giving the low-temperature thermoplastic sheet good shape memory.

[0039] This application also provides a low-temperature thermoplastic sheet, which is prepared from the low-temperature thermoplastic sheet composition described in the above-described scheme.

[0040] This application does not specifically limit the preparation method of the above-mentioned low-temperature thermoplastic sheet, and can be a method well known to those skilled in the art. In some specific embodiments, when the raw materials for preparing the low-temperature thermoplastic sheet do not include a crosslinking agent, the preparation method of the low-temperature thermoplastic sheet is: to blend the above-mentioned matrix material and filler, granulate, and prepare to obtain the low-temperature thermoplastic sheet; in some specific embodiments, when the preparation method of the low-temperature thermoplastic sheet includes a crosslinking agent, the preparation method of the low-temperature thermoplastic sheet is: to blend the above-mentioned matrix material, filler, and crosslinking agent, granulate, form a sheet, and crosslink to obtain the low-temperature thermoplastic sheet.

[0041] In the preparation process of the above-mentioned low-temperature thermoplastic sheet, this application does not have any special limitation on the blending method. It can be melt blending or twin-screw extruder blending, which are well known to those skilled in the art. In some specific embodiments, the blending temperature is 110~180℃, and in some specific embodiments, the blending temperature is 130~160℃.

[0042] This application does not impose any particular limitation on the granulation process; granulation can be performed using methods well known to those skilled in the art. This application also does not impose any particular limitation on the plate-making process; it can be performed using methods well known to those skilled in the art, including but not limited to extrusion or injection molding.

[0043] In some specific embodiments, the crosslinking includes thermal crosslinking and irradiation crosslinking. In some specific embodiments, the crosslinking is irradiation crosslinking. In some specific embodiments, the irradiation crosslinking uses a cobalt source for irradiation, and the irradiation dose is 4~7 kGy. In some specific embodiments, the irradiation dose is 5~6 kGy.

[0044] The test results show that the low-temperature thermoplastic sheet provided by the present invention has an elastic modulus of over 900 MPa, an elongation at break of over 160%, a flexural modulus of over 800 MPa, and a fixation rate of 82%~85%. With the addition of a crosslinking agent, the recovery rate of the low-temperature thermoplastic sheet is 78%~85%, and it has good mechanical strength and shape memory properties.

[0045] The present invention also provides a low-temperature thermoplastic composite board, which includes the above-mentioned low-temperature thermoplastic board.

[0046] In some specific embodiments, the low-temperature thermoplastic composite board includes the aforementioned low-temperature thermoplastic board, a piezoelectric functional layer, and an encapsulation layer; further, the piezoelectric functional layer is formed on the surface of the low-temperature thermoplastic board, and the encapsulation layer is formed on the surface of the piezoelectric functional layer. In some specific embodiments, the piezoelectric functional layer and the encapsulation layer are simultaneously and sequentially formed on both surfaces of the low-temperature thermoplastic board.

[0047] In the low-temperature thermoplastic composite board, the raw materials for preparing the piezoelectric functional layer include lead-free piezoelectric material, tackifying polymer, and dispersing solvent. In the piezoelectric functional layer, the dispersing solvent evaporates after drying, and its content is almost zero. During the preparation of the piezoelectric functional layer, the mass content of the dispersing solvent is 40%~80%, in some specific embodiments it is 43%~72%, in some specific embodiments it is 46%~70%, in some specific embodiments it is 50%~68%, in some specific embodiments it is 53%~66%, in some specific embodiments it is 55%~62%, and in some specific embodiments it is 58%~60%. The mass content of the lead-free piezoelectric material is 5%~50%, in some specific embodiments it is 8%~40%, and in some specific embodiments it is... The lead piezoelectric material has a mass content of 10% to 32%. In some specific embodiments, the lead-free piezoelectric material has a mass content of 16% to 30%, and in some specific embodiments, the lead-free piezoelectric material has a mass content of 18% to 25%. In some specific embodiments, the tackifying polymer has a content of 1% to 30%, and in some specific embodiments, the tackifying polymer has a content of 3% to 26%, and in some specific embodiments, the tackifying polymer has a content of 5% to 24%, and in some specific embodiments, the tackifying polymer has a content of 7% to 21%, and in some specific embodiments, the tackifying polymer has a content of 8% to 18%, and in some specific embodiments, the tackifying polymer has a content of 10% to 16%, and in some specific embodiments, the tackifying polymer has a content of 13% to 15%.

[0048] The lead-free piezoelectric material exhibits good biocompatibility and contains no lead, posing no toxic side effects to the human body. In some specific embodiments, the piezoelectric material comprises one or more of barium titanate, potassium sodium niobate, and sodium bismuth titanate. In some specific embodiments, the lead-free piezoelectric material is selected from one or more of barium titanate, potassium sodium niobate, and sodium bismuth titanate. In some specific embodiments, the lead-free piezoelectric material is selected from one or more of barium titanate and potassium sodium niobate. In some specific embodiments, the lead-free piezoelectric material is selected from barium titanate.

[0049] In some specific embodiments, the tackifying polymer includes one or more of polycaprolactone, thermoplastic polyurethane, and polyvinyl butyral; in some specific embodiments, the tackifying polymer is selected from one or more of polycaprolactone, thermoplastic polyurethane, and polyvinyl butyral; in some specific embodiments, the tackifying polymer is selected from polycaprolactone or polyvinyl butyral.

[0050] In some specific embodiments, the dispersing solvent of the piezoelectric functional layer includes one or more of dichloromethane, acetone, tetrahydrofuran, and isopropanol. In some specific embodiments, the dispersing solvent is selected from one or more of dichloromethane, acetone, tetrahydrofuran, and isopropanol. In some specific embodiments, the dispersing solvent is selected from two of dichloromethane, acetone, tetrahydrofuran, and isopropanol. In some specific embodiments, the dispersing solvent is selected from dichloromethane or tetrahydrofuran.

[0051] In some specific embodiments, to improve the dispersibility of the lead-free piezoelectric material, the piezoelectric functional layer further includes a coupling agent, which includes a silane coupling agent or a carbonate coupling agent. Based on the total mass of all raw materials used in the preparation of the piezoelectric functional layer, the amount of coupling agent added is 0-5 wt%. In some specific embodiments, the amount of coupling agent added is 0.4-4.2 wt%, in some specific embodiments, the amount of coupling agent added is 1.0-3.8 wt%, in some specific embodiments, the amount of coupling agent added is 1.6-3.0 wt%, and in some specific embodiments, the amount of coupling agent added is 2.0-2.6 wt%.

[0052] In some specific embodiments, the piezoelectric functional layer is formed on the surface of the low-temperature thermoplastic sheet by coating. In some specific embodiments, the coating method includes spraying, scraping, dipping or spin coating. In some specific embodiments, the coating method is spraying, dipping or scraping.

[0053] The raw materials for preparing the encapsulation layer include piezoelectric materials and polymers; the finished encapsulation layer is a blend of piezoelectric materials and polymers. In some specific embodiments, the piezoelectric material includes one or more of barium titanate, potassium sodium niobate, and sodium bismuth titanate; in some specific embodiments, the piezoelectric material is selected from one or more of barium titanate, potassium sodium niobate, and sodium bismuth titanate; in some specific embodiments, the piezoelectric material is selected from one or more of barium titanate and potassium sodium niobate; and in some specific embodiments, the piezoelectric material is barium titanate. In some specific embodiments, the polymer includes one or more of polycaprolactone, thermoplastic polyurethane, ethylene-vinyl acetate copolymer, polyolefin elastomer, polyvinylidene fluoride, and polydimethylsiloxane. In some specific embodiments, the polymer is selected from one or more of polycaprolactone, thermoplastic polyurethane, ethylene-vinyl acetate copolymer, polyolefin elastomer, polyvinylidene fluoride, and polydimethylsiloxane. In some specific embodiments, the polymer is selected from two of polycaprolactone, thermoplastic polyurethane, ethylene-vinyl acetate copolymer, polyolefin elastomer, polyvinylidene fluoride, and polydimethylsiloxane. In some specific embodiments, the polymer is selected from thermoplastic polyurethane and polycaprolactone.

[0054] In some specific embodiments, the piezoelectric material has a mass content of 5% to 50%, in some specific embodiments, the piezoelectric material has a mass content of 8% to 43%, in some specific embodiments, the piezoelectric material has a mass content of 10% to 40%, in some specific embodiments, the piezoelectric material has a mass content of 12% to 37%, in some specific embodiments, the piezoelectric material has a mass content of 16% to 33%, and in some specific embodiments, the piezoelectric material has a mass content of 20% to 30%.

[0055] In some specific embodiments, the polymer has a mass content of 50% to 95%, in some specific embodiments, the polymer has a mass content of 58% to 82%, in some specific embodiments, the polymer has a mass content of 60% to 80%, in some specific embodiments, the polymer has a mass content of 64% to 78%, and in some specific embodiments, the polymer has a mass content of 65% to 70%.

[0056] Furthermore, an electrode is disposed on the encapsulation layer, and the material of the electrode is selected from conductive silver paste or copper foil; the electrode is prepared on the encapsulation layer in accordance with methods well known to those skilled in the art, and this application does not impose any special limitations on it.

[0057] This application also provides a foot and ankle orthosis, which includes the low-temperature thermoplastic composite plate described above.

[0058] The low-temperature thermoplastic composite plate provided in this application is used in foot and ankle orthoses, which need to play a major role in weight-bearing and support for the human body. Especially during the patient's walking rehabilitation process, the low-temperature thermoplastic composite plate needs to withstand high-frequency dynamic cyclic loads. This working condition determines that the low-temperature thermoplastic composite plate of this application must have high mechanical properties. The selection of matrix, filler and crosslinking agent in the low-temperature thermoplastic plate gives it high tensile strength, elastic modulus and elongation at break. At the same time, by introducing a piezoelectric functional layer and an encapsulation layer into the low-temperature thermoplastic composite plate, a unique multi-layer composite structure is constructed, so that the orthosis provides piezoelectric function while providing physical support. The low-temperature thermoplastic composite plate provided by this invention not only has good mechanical strength and shape memory properties, but also has low manufacturing cost, high cost performance and is easy to promote.

[0059] To further understand the present invention, the low-temperature thermoplastic sheet and its application provided by the present invention will be described in detail below with reference to the embodiments. The scope of protection of the present invention is not limited by the following embodiments.

[0060] There are no particular restrictions on the source of any raw materials used in this invention; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.

[0061] Example 1

[0062] Polycaprolactone and modified glass fiber were weighed at a mass ratio of 75:25, mixed, and the resulting composition was blended in a twin-screw extruder. The mixture was fed at 120°C, blended at 160°C, granulated, and then made into sheets to obtain low-temperature thermoplastic sheets.

[0063] Example 2

[0064] Weigh out polycaprolactone, ABS, maleic anhydride-grafted ABS, and modified glass fiber according to a mass ratio of 75:5:0.3:20, mix them, and then blend the resulting composition in a twin-screw extruder. Feed at 120°C, blend at 160°C, granulate, and form into sheets to obtain a low-temperature thermoplastic sheet.

[0065] Example 3

[0066] Polycaprolactone, ABS, maleic anhydride-grafted ABS, modified glass fiber, and trimethylolpropane triacrylate were weighed according to a mass ratio of 75:5:0.3:20:2, mixed, and the resulting composition was blended in a twin-screw extruder. The mixture was fed at 120°C, blended at 160°C, granulated, and then made into sheets. The sheets were then subjected to cobalt source irradiation treatment with a dose of 5 kGy to induce crosslinking, resulting in a low-temperature thermoplastic sheet.

[0067] Example 4

[0068] Weigh out polycaprolactone, ABS, maleic anhydride-grafted ABS, modified glass fiber, and trimethylolpropane triacrylate in a mass ratio of 75:5:0.3:20:2, mix them, and then blend the resulting composition in a twin-screw extruder. Feed at 120°C, blend at 160°C, granulate, and form into sheets. Treat the resulting sheets with cobalt source irradiation at a dose of 5 kGy to induce crosslinking and obtain a low-temperature thermoplastic sheet.

[0069] Dissolve 10g of PCL particles in 90mL of THF and stir until completely dissolved to obtain a 10wt% PCL solution. Add 30g of BaTiO3 powder to the PCL solution along with 0.5g of titanate coupling agent. Then, use an ultrasonic disperser with a power of 300W and a frequency of 20kHz to ultrasonically treat the mixture for 30 minutes. Pour the dispersed slurry onto the surface of a low-temperature thermoplastic board and then use a scraper to evenly coat it to form a wet film. Dry it naturally in a fume hood for 24 hours or place it in an oven (40℃, 6 hours) to dry it slowly, obtaining a piezoelectric functional layer with a thickness of about 50~100μm.

[0070] Example 5

[0071] Weigh out polycaprolactone, ABS, maleic anhydride-grafted ABS, modified glass fiber, and trimethylolpropane triacrylate according to a mass ratio of 75:5:0.3:20:2, mix them, and blend the resulting composition in a twin-screw extruder. Feed at 120°C, blend at 160°C, granulate, and form into sheets. Irradiate the obtained sheets with a cobalt source at a dose of 5 kGy to cause crosslinking, and obtain a low-temperature thermoplastic sheet.

[0072] Dissolve 10g of PCL particles in 90mL of THF and stir until completely dissolved to obtain a 10wt% PCL solution. Add 30g of BaTiO3 powder to the PCL solution along with 0.5g of titanate coupling agent. Then, use an ultrasonic disperser with a power of 300W and a frequency of 20kHz to ultrasonically treat the mixture for 30 minutes. Pour the above-dispersed slurry onto the surface of a low-temperature thermoplastic board and then use a scraper to evenly coat it to form a wet film. Dry it naturally in a fume hood for 24 hours or place it in an oven (40℃, 6 hours) to dry it slowly to obtain a piezoelectric functional layer with a thickness of about 50~100μm.

[0073] Weigh out polycaprolactone, polyurethane and barium titanate in a mass ratio of 65:5:30, and then melt-blend them in a mixer at 150°C for 5 minutes to obtain an encapsulation film. Place the following layers from bottom to top: lower encapsulation film, thermoplastic plate with a piezoelectric functional layer formed on the surface, and upper encapsulation film.

[0074] The laminated composite board obtained above is placed in a vacuum bag, the air between the layers is removed, and then heated and pressurized under a vacuum of 80°C and 0.1MPa. Finally, the pressure is maintained and cooled to room temperature, and the upper and lower sealing films are combined with the thermoplastic board to form a dense whole, thus obtaining a low-temperature thermoplastic composite board.

[0075] Example 6

[0076] Polycaprolactone and talc were weighed at a mass ratio of 75:25, mixed, and the resulting composition was blended in a twin-screw extruder. The mixture was fed at 120°C, blended at 160°C, granulated, and then made into sheets to obtain low-temperature thermoplastic sheets.

[0077] Mechanical properties of the test specimen: tensile strength 20 MPa, elastic modulus 607 MPa, flexural modulus 621 MPa.

[0078] The performance of the low-temperature thermoplastic sheets prepared in Examples 1-3 and the low-temperature thermoplastic composite sheets prepared in Examples 4 and 5 was tested: the low-temperature thermoplastic sheets were prepared into standard specimens for performance index testing. Tensile properties were tested according to Chinese National Standard GB / 1040.2-2006 to evaluate their tensile strength, tensile modulus and other mechanical properties; shape memory properties such as fixation rate and recovery rate of the materials were tested by thermomechanical methods; the piezoelectric effect of the periodic stress impact sample was tested by a stress piezoelectric instrument. The results are shown in Table 1.

[0079] Table 1 Performance data of the low-temperature thermoplastic board and low-temperature thermoplastic composite board prepared in the examples

[0080]

[0081] As shown in Table 1, the fillers for the low-temperature thermoplastic sheets in Examples 1 and 2 both used modified glass fiber. Comparing the matrix materials selected as PCL and PCL / ABS combinations, the results show that the PCL / ABS matrix material combination has a higher elastic modulus. Meanwhile, the low-temperature thermoplastic sheet prepared by the low-temperature thermoplastic sheet composition provided in the embodiments of the present invention has good mechanical properties, a low molding temperature, and good shape memory properties. The low-temperature thermoplastic composite sheet provided in the embodiments of the present invention also has a significant piezoelectric effect.

[0082] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0083] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A low-temperature thermoplastic sheet composition, comprising, by weight percentage: Matrix 70%~99%, filler 1%~25%, compatibilizer 0~5%, crosslinking agent 0~5%; The filler includes one or more of talc, modified nanoparticles, and modified fibers.

2. The low-temperature thermoplastic sheet composition according to claim 1, characterized in that, The talc powder has a mesh size of 800-10000 mesh; and / or, the modified nanoparticles are selected from one or more of silane coupling agent modified zinc oxide, silane coupling agent modified silicon dioxide, silane coupling agent modified titanium dioxide, and silane coupling agent modified alumina; and / or, the modified fiber is selected from one or more of silane coupling agent modified basalt fiber, silane coupling agent modified glass fiber, and silane coupling agent modified carbon fiber.

3. The low-temperature thermoplastic sheet composition according to claim 1, characterized in that, The compatibilizer includes one or more of epoxy functional group polymers, isocyanates, and acid anhydrides, and / or the amount of the compatibilizer is 0.1% to 3%; and / or the crosslinking agent includes one or more of triallyl isocyanurate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, benzoyl peroxide, and dicumyl peroxide, and / or the amount of the crosslinking agent is 0.1% to 3%.

4. A low-temperature thermoplastic sheet, prepared from the low-temperature thermoplastic sheet composition according to any one of claims 1 to 3.

5. A low-temperature thermoplastic composite board, characterized in that, Includes the low-temperature thermoplastic sheet as described in claim 4.

6. The low-temperature thermoplastic composite board according to claim 5, characterized in that, The low-temperature thermoplastic composite board further includes a piezoelectric functional layer and an encapsulation layer. The piezoelectric functional layer is formed on the surface of the low-temperature thermoplastic board, and the encapsulation layer is formed on the surface of the piezoelectric functional layer.

7. The low-temperature thermoplastic composite board according to claim 6, characterized in that, The raw materials for preparing the piezoelectric functional layer include lead-free piezoelectric materials, tackifying polymers, and dispersing solvents, and / or the raw materials for preparing the encapsulation layer include piezoelectric materials and polymers.

8. The low-temperature thermoplastic composite board according to claim 7, characterized in that, In the piezoelectric functional layer, the lead-free piezoelectric material includes one or more of barium titanate, potassium sodium niobate, and sodium bismuth titanate; the tackifying polymer includes one or more of polycaprolactone, thermoplastic polyurethane, and polyvinyl butyral; and the dispersing solvent includes one or more of dichloromethane, acetone, tetrahydrofuran, and isopropanol. And / or, in the encapsulation layer, the piezoelectric material includes one or more of barium titanate, potassium sodium niobate, and sodium bismuth titanate; and the polymer includes one or more of polycaprolactone, thermoplastic polyurethane, ethylene-vinyl acetate copolymer, polyolefin elastomer, polyvinylidene fluoride, and polydimethylsiloxane.

9. The low-temperature thermoplastic composite board according to claim 7, characterized in that, Electrodes are disposed on the encapsulation layer, and the material of the electrodes is selected from conductive silver paste or copper foil.

10. An ankle orthosis comprising the low-temperature thermoplastic composite plate as described in any one of claims 6 to 9.

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