Macromolecular multilayer grid structural body, preparation method thereof and application of macromolecular multilayer grid structural body in supporting protection

Abstract

The invention discloses a macromolecular multilayer grid structural body and a preparation method and application thereof in support and protection, and relates to the field of macromolecular materials, and the macromolecular multilayer grid structural body is a three-dimensional grid structure which is integrally formed by melting and extruding a thermoplastic macromolecular material and cooling and shaping in water. The thermoplastic polymer material is selected from at least one of polycaprolactone (PCL) and thermoplastic polyurethane (TPU); according to the molecular multilayer grid structural body, the preparation method thereof and the application of the molecular multilayer grid structural body in supporting and protection, through the integrally-formed three-dimensional grid structure, the molecular multilayer grid structural body has excellent air permeability, elasticity and light weight (low density), uniform supporting and buffering can be provided for the body, meanwhile, air circulation is kept, and stuffiness is avoided.

Description

Technical Field

[0001] This invention relates to polymer materials technology, specifically to a polymer multilayer mesh structure, its preparation method, and its application in support and protection. Background Technology

[0002] Porous or mesh-like polymer materials have attracted attention in various industrial and medical fields due to their lightweight, breathability, and elastic deformation properties. For example, multi-layer monolithic geogrids, with their unique porous structure, can provide enhanced vertical compression performance for stabilizing soils or granular materials. In the biomedical field, polycaprolactone (PCL), due to its good biocompatibility and biodegradability, is often used to prepare tissue engineering scaffolds; porous structures with controllable pore sizes can be fabricated using techniques such as supercritical carbon dioxide foaming.

[0003] Existing materials used for limb immobilization and protection, such as traditional plaster casts or ordinary polymer splints, have several shortcomings: poor breathability, leading to skin discomfort; heavy texture, resulting in a poor patient experience; lack of plasticity or good plasticity, making it difficult to achieve personalized fit to the limb; and limited functionality, lacking additional features such as antibacterial and heat dissipation. Although institutions such as the University of Tokyo have developed novel lightweight and tough three-dimensional mesh porous polymer materials, their main applications are concentrated in the field of separation membranes, and they have not yet systematically addressed the comprehensive needs for material plasticity, functional versatility, and ease of use in medical support and protection.

[0004] Meanwhile, introducing functional additives into polymer matrices to endow materials with additional properties is an important direction in materials science. For example, transition metals (such as silver, copper, and zinc) and their nanocomposites have been extensively studied. They exhibit significant antibacterial properties by releasing metal ions, generating reactive oxygen species, or photothermal effects, showing great potential in combating bacterial infections. However, how to stably and uniformly composite these functional components into supportive and protective materials with complex three-dimensional mesh structures suitable for long-term skin contact, while achieving a balance between material mechanical properties, molding processes, and functionality, remains an unsolved technical problem. Summary of the Invention

[0005] The primary objective of this invention is to overcome the shortcomings of existing support and protective materials in terms of breathability, plasticity, lightweight and functional versatility, and to provide a high-performance polymer multilayer mesh structure.

[0006] The second objective of this invention is to provide a method for preparing the above-mentioned mesh structure, which is stable, efficient, and capable of achieving precise control of the mesh structure and uniform compounding of functional components.

[0007] The third objective of this invention is to expand the application of the aforementioned mesh structure, particularly in the field of medical human body support and protection, such as the preparation of customizable orthopedic external fixation braces, surgical positioning pads, pressure ulcer prevention pads, and limb end protectors.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a polymer multilayer mesh structure, which is a three-dimensional mesh structure integrally formed by melt extrusion and water cooling of thermoplastic polymer material; wherein the thermoplastic polymer material is selected from at least one of polycaprolactone (PCL) and thermoplastic polyurethane (TPU).

[0009] The thermoplastic polymer material is selected from polycaprolactone (PCL), thermoplastic polyurethane (TPU), or a combination thereof. The structure is a one-piece, multi-layered, three-dimensional mesh structure formed by melt extrusion and water molding of the thermoplastic polymer material. The mesh structure exhibits a three-dimensional interconnected porous morphology with transparent pores and smooth pore walls.

[0010] Furthermore, the polymer material also includes an additive, which is an antibacterial additive, and the antibacterial additive is at least one of silver, silver ion compounds, and silver-loaded inorganic particles.

[0011] The antibacterial additive is selected from at least one of silver powder, silver-loaded inorganic particles, and silver ion compounds to provide a long-lasting antibacterial and bacteriostatic effect.

[0012] Furthermore, the polymer material also includes additives, which are temperature-regulating additives, and the temperature-regulating additives are at least one of iron, aluminum, copper, iron oxide, and thermochromic materials.

[0013] Temperature regulating / indicating additives: selected from at least one of iron powder, aluminum powder, copper powder, iron oxide, and thermochromic materials. Metal powders can enhance the thermal conductivity and heat dissipation properties of materials, while thermochromic materials can change color at specific temperatures, especially when molding in hot water, serving as an indication that the structure has reached the molding temperature.

[0014] Furthermore, it also includes calcium carbonate filler accounting for 0-30% of the total weight of the polymer material, and / or crosslinking agent accounting for 0.1-2% of the total weight of the polymer material.

[0015] To adjust the material density, cost, or whiteness, calcium carbonate powder accounting for 0-30% of the total weight of the substrate can be added to the substrate. To improve the crosslinking degree and dimensional stability of the material, a crosslinking agent accounting for 0.1-2% of the total weight of the polymer material, such as dicumyl peroxide (DCP), can also be added.

[0016] A method for preparing the above-described polymer multilayer mesh structure includes the following steps:

[0017] S1. Mix the raw materials evenly;

[0018] Add one or more selected polymer raw material particles (such as PCL or TPU) and other solid additives (such as calcium carbonate, metal powder, crosslinking agent, etc.) into the mixing tank and stir thoroughly until they are evenly mixed.

[0019] S2. Feed the mixture into the extruder and melt and plasticize it under a temperature gradient of 100-170℃.

[0020] The uniformly mixed raw materials are fed into the extruder via a feeder. The extruder is equipped with multiple temperature zones for gradient heating, allowing the raw materials to gradually melt and plasticize. An exemplary extruder heating temperature zone setting is as follows: Zone 1 100-110℃, Zone 2 115-125℃, Zone 3 125-135℃, Zone 4 135-140℃, Zone 5 140-145℃, Zone 6 145-150℃, Zone 7 150-160℃; Transition body 160-165℃, Die head connector 165-170℃.

[0021] S3. The molten material is extruded through a die with a porous structure to form a fine stream of melt.

[0022] After being filtered by a screen changer, the molten material is extruded through a die (head) with multiple rows of precision micropores, forming multiple streams of high-temperature melt. The die temperature is uniformly controlled at 155-165℃.

[0023] S4. The melt is cooled by flowing water, bonded together and stretched to form a three-dimensional mesh structure;

[0024] The extruded high-temperature melt stream immediately enters a constant-temperature water tank, where it is cooled, stretched, and bonded together to form a mesh, ultimately creating a three-dimensional mesh structure.

[0025] S5. The formed mesh structure is pulled, dehydrated and dried.

[0026] After being formed, the mesh is discharged from the water tank by multi-stage traction rollers, and surface moisture is removed by a dehydration device and a hot air drying system.

[0027] After drying, the continuous mesh material is measured and automatically cut to obtain padding material of the specified length. Secondary cutting and edge sealing can be performed using a cutting machine, heating and fusing machine, or high-frequency fusing machine according to customer needs. The mesh can also be heat-fused with breathable mesh fabric, brushed fabric, or other materials to create composite products.

[0028] Further, in step S2, the temperature zones of the extruder are set as follows: Zone 1 100-110℃, Zone 2 115-125℃, Zone 3 125-135℃, Zone 4 135-140℃, Zone 5 140-145℃, Zone 6 145-150℃, and Zone 7 150-160℃; the temperature of the die head is 155-165℃; in step S4, the traction speed is 0.5-1.0 m / s.

[0029] The application of the above-described polymer multilayer mesh structure or the polymer multilayer mesh structure prepared by the above-described method in the preparation of human body support and protection devices.

[0030] Taking advantage of the material's ability to soften at 60-80℃, it can be molded on-site into neck braces, arm braces, and lower leg fixation braces that conform to the contours of the patient's limbs. After molding, the edges are rounded, there are no burrs, and it is comfortable to wear.

[0031] Furthermore, the human body support and protection device is a medical brace that can be thermoformed at low temperatures, a pressure ulcer prevention positioning pad, a limb end protector, or a sports protection pad.

[0032] Taking advantage of its breathability and elasticity, it is used as a surgical positioning pad, a pressure ulcer prevention pad for long-term bedridden patients, and a wheelchair cushion. With the addition of antibacterial components, it is especially suitable for scenarios requiring high hygiene standards.

[0033] Furthermore, the medical brace is softened by heating at 60-80℃ and then shaped into a neck brace, arm brace, or leg brace that fits the shape of the human body.

[0034] The mesh structure is provided with local reinforcement points or functional expansion holes formed by hot melting.

[0035] This mesh structure supports localized thermal fusion reinforcement, allowing for targeted strengthening of areas requiring additional support. Furthermore, thermal fusion can be used to randomly or as needed create targeted holes in the mesh, which can be used for dressing changes, observation, or drainage during medical procedures, greatly enhancing functionality and convenience.

[0036] Provides soft, breathable end protection and pressure regulation for amputees or patients who have undergone finger / toe surgery.

[0037] Furthermore, the medium is a hot air gun, a constant temperature oven, or a hot water bath device used to heat and soften the polymer multilayer mesh structure.

[0038] Compared with the prior art, the polymer multilayer mesh structure, its preparation method, and its application in support and protection provided by the present invention have the following beneficial effects:

[0039] The one-piece molded three-dimensional mesh structure combines excellent breathability, elasticity, and lightweight (low density), providing uniform support and cushioning for the body while maintaining air circulation and preventing stuffiness.

[0040] The material can soften and be shaped at relatively low temperatures (60-80℃), and solidify after cooling, achieving a personalized and perfect fit to human body parts, thus solving the problem of poor adaptability of traditional materials.

[0041] Through formula design, materials can be flexibly endowed with additional functions such as antibacterial properties, thermal conductivity, and temperature-sensitive color change to meet specific needs in different scenarios.

[0042] The supported product allows for localized heat fusion reinforcement and targeted pore enlargement, which expands its application in clinical care, such as facilitating wound management and combining support with therapeutic assistance. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0044] Figure 1 The process flow of the preparation method provided in the embodiments of the present invention;

[0045] Figure 2 A macroscopic schematic diagram of a medical brace made of a polymer multilayer mesh structure provided in an embodiment of the present invention;

[0046] Figure 3 This is a schematic diagram illustrating the application of a medical brace made of a polymer multilayer mesh structure provided in an embodiment of the present invention to a human limb. Detailed Implementation

[0047] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0048] As attached Figure 1 To be continued Figure 3 As shown:

[0049] Example 1: Preparation of 100% PCL-based plastic mesh material

[0050] This embodiment demonstrates a complete process for preparing high-performance mesh materials using pure bio-based polyester, with the product characterized by excellent biocompatibility, low-temperature plasticity, and complete biodegradability.

[0051] 1. Raw materials and formula:

[0052] Main material: 100% polycaprolactone (PCL) resin. The selected type is CAPA 6800 (Perstorp), with a number-average molecular weight (Mn) of approximately 80,000 and a melt index (190℃ / 2.16 kg) of 3 g / 10min. The raw material particles must have a smooth surface and be free of impurities to ensure melt uniformity and the transparent texture of the final product.

[0053] 2. Main equipment and processes:

[0054] Mixing: Add PCL particles to a high-speed mixing tank (500L capacity) and mix at 200 rpm for 15 minutes at room temperature to ensure uniform material distribution.

[0055] Extrusion and plasticizing: A single-screw extruder (screw diameter 65mm, L / D=32:1) is used. Material is fed into the hopper via a hollow feeder. A precise temperature control program is set to achieve gradient melting and stable conveying of PCL.

[0056] Equipment Section Temperature setting (°C) Function Description Extruder Zone 1 100 Solid conveying, preheating Extruder Zone 2 115 Start to melt Extruder Zone 3 125 Fully melt Extruder Zone 4 135 Homogenize Extruder Zone 5 140 Homogenization, turbocharging Extruder Zone 6 145 Stable delivery Extruder Zone 7 155 Final homogenization transition body 160 Connection and insulation Network switch 160 Filtering impurities Connector 165 Connecting mold head Mold head (eight zones in total) 160 (Districts) Precision melt distribution and wire extrusion

[0057] Molding and Cooling: The melt is extruded into filaments through a multi-hole die (200 holes, 0.5mm diameter) and immediately immersed vertically into a constant-temperature molding water tank at 25±1℃. Upon contact with water, the melt cools and solidifies, and according to the principles of fluid dynamics, the filaments bond together to form a stable three-dimensional mesh structure. This process is a purely physical change and does not use any chemical adhesives.

[0058] Traction and Drying: The formed wet mesh mat is conveyed backward through a conveyor within a water tank and a subsequent multi-stage traction system. The traction speed is controlled as follows: forming roller speed in the water tank 0.60 m / s, first-stage traction speed 0.61 m / s, second-stage traction speed 0.61 m / s, and final belt traction speed 0.62 m / s. The slightly increasing traction speed provides moderate longitudinal stretching to the mesh, which helps with molecular orientation and improves product strength. Afterward, the mesh mat is dehydrated by rollers and then enters a 55°C hot air drying tunnel to thoroughly remove surface and pore moisture.

[0059] Cutting and post-processing: After drying, the continuous mesh mat is monitored by an online density meter, and its density is stabilized at 0.13 g / cm³. It is then cut to a fixed length (2.0 meters) on an automatic cutting bed. According to customer drawings, precise cutting and edge sealing are performed using a CNC cutting machine or an 80℃ heating and melting machine to ensure smooth, burr-free edges.

[0060] 3. Product performance and applications:

[0061] Appearance and structure: The finished product is a milky white, semi-transparent, multi-layered three-dimensional mesh. It appears crystal clear in hot water, with smooth pore walls and a soft and elastic feel.

[0062] Core features:

[0063] Low-temperature plasticity: Soften in 65-70℃ hot air or hot water for about 2-3 minutes, then it can be used for personalized shaping. It can easily conform to complex curves such as the neck and arms, and set after cooling (about 1 minute at room temperature), providing stable support.

[0064] Biocompatibility and biodegradability: Meets ISO 10993 biocompatibility requirements. Under composting conditions (58°C), it can be completely biodegraded within 12-24 months.

[0065] Lightweight and breathable: Extremely lightweight, the fully breathable structure effectively prevents sweat buildup.

[0066] Application Examples: Directly used in the manufacture of medical low-temperature thermoplastic plates. Medical staff can cut them according to the patient's limb size, and after heating and softening, they can be molded into highly conforming fracture fixation braces, scoliosis orthotic liners, or burn pressure masks. They can be directly removed after use, are comfortable for the patient's skin, and the material is recyclable and biodegradable.

[0067] Example 2: Preparation of 80% PCL + 20% CaCO3 filled reinforced mesh material

[0068] This embodiment achieves material cost optimization and enhanced mechanical properties by introducing calcium carbonate filler, expanding its application in non-medical fields and scenarios with higher requirements for support.

[0069] 1. Raw materials and formula:

[0070] PCL resin (same as in Example 1): 80%

[0071] Heavy calcium carbonate (CaCO3): 20%. A type with a particle size D50 of 2μm and a stearic acid surface coating was selected to improve its dispersibility and compatibility in the PCL matrix.

[0072] 2. Key points for process adjustment:

[0073] The basic process flow is the same as in Example 1.

[0074] Key adjustments: Since the addition of CaCO3 increases melt viscosity and heat capacity, and may affect crystallization behavior, the process needs to be adjusted accordingly.

[0075] Temperature fine-tuning: Increase the temperature of zones four to seven of the extruder by 5-8°C based on Example 1, and increase the die temperature to 165°C to ensure that the filler and melt are fully mixed and maintain good fluidity.

[0076] Traction speed adjustment: Reduce the traction speed of each level by about 8% (e.g., reduce the belt traction to 0.57 m / s) to extend the cooling and shaping time of the mesh in the water tank and prevent shrinkage stress concentration and deformation caused by the packing.

[0077] Screw selection: Use a barrier-type screw with stronger mixing and shearing capabilities to break up packing agglomerates and achieve uniform dispersion.

[0078] 3. Product performance and applications:

[0079] Appearance and structure: The finished product is a pure white opaque mesh, and its texture is more rigid than that of the product in Example 1.

[0080] Core features:

[0081] Enhanced support and dimensional stability: flexural modulus increased by approximately 40%, improved resistance to compressive permanent deformation, and better shape retention under long-term loads.

[0082] Economic efficiency: Material costs are significantly reduced.

[0083] Retained plasticity: It retains good low-temperature (70-75℃) plasticity and can be processed again.

[0084] Application examples: Suitable for industrial and consumer goods sectors, such as cushioning pads for transporting precision instruments, pet mattress cores, yoga mat inner cores, or packaging liners requiring a certain level of rigidity. Its enhanced support and lower cost offer significant advantages in these applications.

[0085] Example 3: Preparation of a 99% TPU + 1% DCP cross-linked high-elasticity mesh material

[0086] This embodiment introduces a chemical crosslinking agent to dynamically crosslink and modify thermoplastic polyurethane (TPU), aiming to obtain a high-end mesh material with excellent resilience, heat resistance and fatigue resistance.

[0087] 1. Raw materials and formula:

[0088] Thermoplastic polyurethane (TPU): 99%. Polyether type is selected, with a hardness of approximately 85A to ensure high elasticity and hydrolysis resistance.

[0089] Crosslinking agent: dicumyl peroxide (DCP): 1%. (Safety warning: DCP is a flammable solid. Mixing should be carried out in an explosion-proof environment, and operators should wear professional protective equipment.)

[0090] 2. Key points for process adjustment:

[0091] The basic process flow is the same as in Example 1.

[0092] Key adjustment: The core of the process lies in precisely controlling the decomposition and cross-linking reactions of DCP.

[0093] Temperature strategy: Significantly increase the temperature in the later stages to activate crosslinking. Set the extruder zone 6 to 150℃ and zone 7 to 165℃; increase the die temperature to 170℃. This temperature window ensures TPU melting while shortening the DCP half-life, effectively initiating crosslinking during melt residence.

[0094] Main unit monitoring: Crosslinking reaction will cause the melt viscosity to increase, so the main unit current needs to be closely monitored. Its value will usually increase by 10-15%, which is normal.

[0095] Residence time: By adjusting the screw speed, the residence time of the material in the high-temperature zone (>160℃) is controlled to be 1.5-2 minutes to ensure a moderate degree of crosslinking.

[0096] 3. Product performance and applications:

[0097] Appearance and structure: The finished product is a slightly yellow transparent mesh with a very noticeable elastic feel.

[0098] Core features:

[0099] Ultra-high resilience and resistance to permanent deformation: The recovery rate after 50% compression is >95%, far superior to uncrosslinked TPU (approximately 85%). After 100,000 repeated compressions, the thickness loss rate is <5%.

[0100] Improved heat resistance: The heat distortion temperature is increased, making it less prone to softening and collapsing in high-temperature environments in summer or under continuous pressure.

[0101] Excellent fatigue resistance: suitable for dynamic repeated load scenarios.

[0102] Application examples: Designed specifically for high-performance sports protection and durable consumer products. Examples include: midsole cushioning layers in high-end running shoes, protective gear for athletic sports (such as motorcycle riding armor linings), high-quality office chair cushions, and industrial shock-absorbing pads that need to withstand dynamic loads over long periods.

[0103] Comparative Example: A Comprehensive Comparison with Traditional Plaster Cast Fixation Systems

[0104] To objectively evaluate the comparative advantages of the materials of this invention, the most commonly used traditional plaster bandages in clinical practice were selected as the comparative example, and a systematic comparison was conducted from multiple dimensions.

[0105] Comparative products: A plaster bandage system for fixing forearm fractures (taking ordinary plaster bandage as an example) is compared with a malleable brace made of the material of Embodiment 1 of the present invention.

[0106] Table 1. Comparison results of the present invention with traditional plaster bandages:

[0107] Comparison Dimensions Traditional plaster bandage PCL mesh support of the present invention Comparative analysis and advantages of the present invention 1. Molding principle <![CDATA[Chemical curing: Gypsum (CaSO4·½H2O) rehydrates and crystallizes into gypsum dihydrate (CaSO4·2H2O) upon contact with water, forming a hard shell.]]> Physical shaping: After the material is heated and softened, it is shaped by external force, and after cooling, the shape is fixed based on the freezing of polymer chain segments. Advantages of the principle: The process is reversible and controllable, with no toxic side chemical reactions and no risk of exothermic burns. 2. Operation and Time This procedure requires professional medical personnel. The entire process of wrapping, shaping, and curing takes approximately 15-30 minutes, and complete drying requires 24-48 hours. Easy to operate. Soften (3 min) + shape (2 min) + cool and set (1 min), totaling about 5-10 minutes, ready to use immediately. Efficiency advantages: Significantly shortens operation time, reduces the burden on medical staff, and improves patient experience. 3. Weight It is very heavy; a forearm cast weighs approximately 400-600 grams. Extremely lightweight, with braces of the same specifications weighing only 60-100 grams, about 1 / 6 the weight of plaster. Comfort advantages: It greatly reduces the load on the patient's limbs and reduces fatigue and discomfort caused by weight. 4. Breathability It is completely airtight. The dense plaster layer hinders the exchange of air and moisture. Completely transparent. The three-dimensional mesh structure allows for free airflow. Health and hygiene advantages: It fundamentally eliminates problems such as stuffy, damp, itchy, eczema and even infection of the skin. 5. Plasticity / Adaptability There is a plastic period of about 5-10 minutes before it hardens, after which it becomes completely rigid and cannot be adjusted. The precision of the shaping depends on the physician's experience. It can be repeatedly reshaped. If the alignment is not ideal or the swelling subsides, it can be reheated and adjusted to achieve a precise and personalized fit. Clinical advantages: It supports dynamic adjustments to adapt to changes in the limbs during the treatment cycle and improves fixation effectiveness. 6. Disassembly and Re-inspection A plaster saw must be used for forceful removal, which carries a risk of damage and cannot be reused. Follow-up examinations (such as X-rays) may require removal or penetration of the plaster cast. It can be easily removed and worn at any time, facilitating skin cleaning, dressing changes, and physical therapy. It offers excellent X-ray visibility, allowing for follow-up examinations without removal. Advantages in ease of use: greatly facilitates clinical follow-up and patients' daily lives, and supports intermittent fixed treatment. 7. Reuse and Environmental Protection After demolition, the waste will become solid medical waste, which is non-recyclable and non-degradable, increasing the environmental burden. The material (PCL-based) is recyclable or can be completely biodegraded under certain conditions. Scrap materials can be melt-re-granulated. Environmental advantages: It aligns with the concepts of green healthcare and circular economy, reducing the environmental footprint throughout the entire life cycle. 8. Functional Expansion None. It is only a passive support structure. It can be flexibly integrated with antibacterial, thermal conductivity, and magnetic therapy functions through formulation. It supports localized thermal pore enlargement for dressing changes or observation. Functional advantages: Upgraded from "passive fixation" to "active nursing and treatment support platform".

[0108] As can be seen from the detailed descriptions of the above embodiments and comparative examples, the polymer multilayer mesh structure and its preparation method provided by the present invention not only achieve core breakthroughs in material properties such as lightweight, breathability, and plasticity, but also, through flexible design of formulations and processes, derive a product portfolio covering basic, filled and reinforced, and chemically cross-linked functional types. Compared with existing technologies such as traditional plaster, the materials of the present invention have achieved comprehensive and substantial progress in terms of patient comfort, clinical operation efficiency, functional diversity, and environmental friendliness, and are particularly suitable for the urgent needs of modern medicine for personalized, humanized, and intelligent fixation and protection solutions.

[0109] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A polymer multilayer mesh structure, characterized in that, A three-dimensional mesh structure integrally formed from thermoplastic polymer material through melt extrusion and water cooling and shaping; the thermoplastic polymer material is selected from at least one of polycaprolactone (PCL) and thermoplastic polyurethane (TPU).

2. The polymer multilayer mesh structure according to claim 1, characterized in that, The polymer material also includes additives, which are antibacterial additives, and the antibacterial additives are at least one of silver, silver ion compounds, and silver-loaded inorganic particles.

3. The polymer multilayer mesh structure according to claim 1, characterized in that, The polymer material also includes additives, which are temperature-regulating additives, and the temperature-regulating additives are at least one of iron, aluminum, copper, iron oxide, and thermochromic materials.

4. A polymer multilayer mesh structure according to claim 3, characterized in that, It also includes calcium carbonate filler accounting for 0-30% of the total weight of the polymer material, and / or crosslinking agent accounting for 0.1-2% of the total weight of the polymer material.

5. A method for preparing a polymer multilayer mesh structure as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Mix the raw materials evenly; S2. Feed the mixture into the extruder and melt and plasticize it under a temperature gradient of 100-170℃. S3. The molten material is extruded through a die with a porous structure to form a fine stream of melt. S4. The melt is cooled by flowing water, bonded together and stretched to form a three-dimensional mesh structure; S5. The formed mesh structure is pulled, dehydrated and dried.

6. The method for preparing a polymer multilayer mesh structure according to claim 5, characterized in that, In step S2, the temperature zones of the extruder are set as follows: Zone 1 100-110℃, Zone 2 115-125℃, Zone 3 125-135℃, Zone 4 135-140℃, Zone 5 140-145℃, Zone 6 145-150℃, and Zone 7 150-160℃; the temperature of the die head is 155-165℃; in step S4, the traction speed is 0.5-1.0 m / s.

7. The application of a polymer multilayer mesh structure as described in any one of claims 1-4 or a polymer multilayer mesh structure prepared by the method described in claim 5 or 6 in the preparation of human body support and protection devices.

8. The application according to claim 7, characterized in that, The human body support and protection equipment refers to medical braces that can be thermoformed at low temperatures, pressure ulcer prevention pads, limb end protectors, or sports protective pads.

9. The application according to claim 7, characterized in that, The medical brace is shaped into a neck brace, arm brace, or leg brace that fits the body part after being heated and softened at 60-80℃. The mesh structure is provided with local reinforcement points or functional expansion holes formed by hot melting.

10. A medium for implementing the application of claim 9, characterized in that, The medium is a hot air gun, a constant temperature oven, or a hot water bath used to heat and soften the polymer multilayer mesh structure.

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