A 3d printed gel composition for sports protection pads and method of preparation thereof

Abstract

This invention provides a 3D-printed gel composition for sports protective pads and its preparation method, relating to the fields of gel materials and 3D printing technology. The 3D-printed gel composition for sports protective pads of this invention comprises the following materials in parts by weight: 10-25 parts of trimethylolpropane trimethacrylate, 25-35 parts of polyurethane acrylate, 5-15 parts of acrylated eutectic solvent, 1-5 parts of methacrylated-β-cyclodextrin inclusion complex loaded with antibacterial agent, 5-10 parts of amine-modified polyether acrylate, and 0.1-5 parts of additives. This invention aims to solve the problems of poor tear resistance and easy fatigue collapse in existing 3D-printed foam pads due to the physical disruption of the cross-linking network by micropores, while also addressing the issues of traditional pads softening upon absorbing sweat and failing to provide adaptive support and intelligent long-lasting antibacterial properties based on the athlete's sweating state.

Description

Technical Field

[0001] This invention relates to the fields of gel materials and 3D printing technology, specifically to a 3D printed gel composition for sports protective pads and its preparation method. Background Technology

[0002] In prolonged sedentary activities such as road cycling, the pressure resistance, breathability, and sweat-wicking properties of sports protective pads are crucial to the athlete's comfort. Traditional cycling shorts pads are mostly made of layers of sponge of different densities, but sponge materials have poor resistance to chemical corrosion, are prone to fatigue and collapse after prolonged use, and are extremely prone to accumulating sweat and breeding bacteria; while thermo-pressed air cushion modules are expensive, and the edge seams not only have an unpleasant feeling, but also cannot withstand subsequent thermoforming processes in garment manufacturing.

[0003] In recent years, the fabrication of flexible lattice materials or the addition of foaming agents to prepare microporous elastomer gaskets using 3D printing technologies such as DLP has become a research hotspot in the industry (e.g., Chinese patent application CN118206695A). However, existing 3D-printed foamed gaskets still have significant limitations in practical applications and production:

[0004] First, the microbubbles generated during foaming are randomly distributed within the material, disrupting the topological integrity of the polymer cross-linking network. When faced with the high-frequency alternating shear stress generated by cycling, stress concentration and microcrack propagation easily occur at the pores, resulting in poor tear resistance and irreversible fatigue collapse. At the same time, the foaming process is extremely difficult to control precisely in actual production, leading to a low product yield.

[0005] Secondly, when existing 3D printing resin materials come into contact with large amounts of human sweat, the cross-linked network is prone to excessive swelling and plasticization, leading to a sharp decline in the material's macroscopic mechanical properties (softening). During periods when athletes are sweating intensely and expending a lot of energy, urgently needing stronger support, the pads instead become weak and collapse, failing to provide adaptive response protection.

[0006] Finally, to address the issue of bacterial growth caused by sweat, current technologies typically involve directly mixing free antibacterial agents into the resin solution. However, in the post-processing stages of actual 3D printing production, such as using alcohol solvents like ethanol for ultrasonic deep cleaning, these free small-molecule antibacterial agents are easily extracted and eluted in large quantities, severely damaging the antibacterial function of the finished product. Even if some is retained, it will be rapidly lost due to daily evaporation and sweat rinsing during long-term use, resulting in a very short odor-resistant lifespan.

[0007] Therefore, there is an urgent need for a novel technical solution that combines extremely high tear resistance and fatigue resistance with adaptive hardening and reinforcement based on perspiration volume, and also features anti-washing properties during production and long-lasting, sustained-release antibacterial and deodorizing functions. Based on this, the present invention provides a 3D-printed gel composition for sports protective pads and its preparation method. Summary of the Invention

[0008] The purpose of this invention is to provide a 3D-printed gel composition for sports protective pads and its preparation method, aiming to solve the problems of poor tear resistance and easy fatigue collapse of existing 3D-printed foam pads due to the physical destruction of cross-linking networks by micropores. At the same time, it solves the problem that traditional pads soften when exposed to sweat and cannot provide adaptive support and intelligent long-lasting antibacterial properties according to the athlete's sweating state.

[0009] On one hand, the present invention provides a 3D printing gel composition for sports protective pads, comprising the following materials in parts by weight: 10-25 parts of trimethylolpropane trimethacrylate, 25-35 parts of polyurethane acrylate, 5-15 parts of acrylated eutectic solvent, 1-5 parts of methacrylated-β-cyclodextrin inclusion complex loaded with antibacterial agent, 5-10 parts of amine-modified polyether acrylate, and 0.1-5 parts of additives.

[0010] Furthermore, the acrylate eutectic solvent is a transparent liquid monomer formed at room temperature by strong hydrogen bonding between a hydrogen bond acceptor and a hydrogen bond donor containing polymerizable double bonds.

[0011] Furthermore, the hydrogen bond acceptor is choline chloride, and the hydrogen bond donor containing polymerizable double bonds includes acrylic acid and / or hydroxyethyl methacrylate.

[0012] Furthermore, the preparation method of the acrylated eutectic solvent includes: mixing hydrogen bond acceptor and hydrogen bond donor in a molar ratio of 1:2-3, and magnetically stirring at 55-65°C until a transparent and homogeneous eutectic solvent liquid is formed.

[0013] Further, the preparation method of the methacrylated-β-cyclodextrin inclusion complex loaded with antibacterial agent includes: dissolving methacrylated-β-cyclodextrin in a mixed solvent of deionized water and anhydrous ethanol at a volume ratio of 9:1 to prepare a 10-15% (w / w) MA-β-CD solution; pre-dissolving thymol in anhydrous ethanol, wherein the molar ratio of methacrylated-β-cyclodextrin to thymol is 1:1, and then adding it to the MA-β-CD solution; continuously stirring and incorporating the mixture in a constant temperature water bath at 40-50℃ in the dark for 5-6 hours; after the reaction is completed, removing the ethanol from the mixture using a rotary evaporator, and then placing it in a freeze dryer for vacuum freeze drying at -50℃ for 40-50 hours to obtain the methacrylated-β-cyclodextrin inclusion complex loaded with antibacterial agent.

[0014] Furthermore, the preparation method of the methacrylated β-cyclodextrin includes:

[0015] (1) Dissolve 0.01 mol β-cyclodextrin in 100 mL N,N-dimethylformamide, add 0.1 mol triethylamine and 4-dimethylaminopyridine, and stir under nitrogen protection until completely dissolved;

[0016] (2) Place the reaction system in an ice-water bath at 0-5℃ and slowly add 0.15 mol of methacrylic anhydride over a period of 2-3 hours; then remove the ice bath and continue to stir the reaction magnetically at room temperature in the dark for 40-50 hours.

[0017] (3) After the reaction is complete, the reaction solution is slowly dripped into a large amount of ice-cold deionized water to precipitate the precipitate; the precipitate is filtered and washed repeatedly with deionized water and a small amount of ethanol three times to remove unreacted acid and solvent; finally, it is placed in a vacuum drying oven at 40°C and dried for 24 hours to obtain the product.

[0018] Further, the molar ratio of β-cyclodextrin, triethylamine, 4-dimethylaminopyridine to methacrylic anhydride is 1:(10-12):(0.5-1.0):(10-15).

[0019] Furthermore, 8-12 mL of N,N-dimethylformamide is added for every 1 g of the β-cyclodextrin.

[0020] Furthermore, the adjuvant includes an antioxidant and an initiator in a weight ratio of 1:4.

[0021] Furthermore, the antioxidants include antioxidant 1010 and antioxidant 168.

[0022] Furthermore, the initiator is a TPO initiator.

[0023] On the other hand, the present invention also provides a method for preparing a 3D-printed gel composition for sports protective pads, the steps of which include:

[0024] S1. The polyurethane acrylate is heated to a fluid state, and under light-protected conditions, trimethylolpropane trimethacrylate, amine-modified polyether acrylate, and methacrylated-β-cyclodextrin inclusion complex loaded with antibacterial agent are added sequentially and dispersed at high speed until completely dissolved. Then, acrylated eutectic solvent is added and homogeneous stirring is performed.

[0025] S2. Add antioxidants and initiator additives, stir and degas under negative pressure, and cool to room temperature to obtain the final product.

[0026] Furthermore, the degassing treatment is performed at a temperature of 55℃-65℃, a pressure of -0.08MPa to -0.1MPa, and a time of 30-60 minutes.

[0027] The beneficial effects of this invention are as follows:

[0028] This invention innovatively combines esterified eutectic solvent (DES) with a methacrylated β-cyclodextrin inclusion complex loaded with an antibacterial agent. After curing, MA-β-CD with multiple active double bonds serves as an organic rigid multifunctional crosslinking center, embedding its rigid, truncated conical macrocyclic skeleton into the network and anchoring the polar flexible chain segments formed by DES with high density. When athletes sweat profusely, the DES phase region absorbs water and tends to swell. However, due to the strong topological constraint of the rigid cyclodextrin core, the chain segments cannot freely extend and relax plasticize. Its internal expansion stress can only be directionally squeezed towards the direction of the 3D-printed micropores (restricted swelling). This not only makes the pores narrow rapidly to provide aerodynamic damping, but also stimulates the strain hardening effect of the molecular chains, solving the problem of existing materials softening upon water absorption and achieving a true adaptive response of "the more you sweat, the stronger the support."

[0029] This invention achieves a slow-release antibacterial function triggered by sweat. Before sweating during exercise, the natural antibacterial agent (thymol) is firmly encapsulated in the hydrophobic cavity of the cyclodextrin, preventing evaporation and loss. It also effectively prevents the violent extraction and elution of small-molecule antibacterial agents by polar solvents during post-3D printing processes, such as ultrasonic cleaning with large amounts of anhydrous ethanol. In practical use, it achieves long-lasting antibacterial action triggered by slightly acidic sweat, competitively releasing the antibacterial agent upon contact with sweat. This solves the problems of traditional pads where free antibacterial agents are easily volatile, have a short lifespan, and are easily washed away by large amounts of sweat, achieving a long-lasting deodorizing and antibacterial effect.

[0030] In this invention, the organic rigid macrocyclic (MA-β-CD) structure effectively disperses the high-frequency shear stress generated during cycling, and the strong hydrogen bond network formed with the eutectic solvent network produces a synergistic dissipation effect. Without the need for a foaming process, the tear strength of the molded part can exceed 52.8 kN / m, and the rebound retention rate after 50,000 high-frequency fatigue cycles reaches over 99%, significantly improving the service life of the sports protective pad. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of a sports protective pad prepared by 3D printing gel composition in Example 1 of the present invention;

[0033] Figure 2 This is a schematic diagram of a sports protective pad prepared by 3D printing gel composition in Example 1 of the present invention. Detailed Implementation

[0034] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0035] It should be noted that the trimethylolpropane trimethacrylate (CAS No.: 3290-92-4) and polyurethane acrylate (CAS No.: 68987-79-1) used in this invention were both purchased from Wuhan Kemike Biomedical Technology Co., Ltd.

[0036] Amine-modified polyether acrylate, CAS No.: 188012-57-9, purchased from Hubei Xinjiecheng Chemical Technology Co., Ltd.

[0037] β-Cyclodextrin, CAS No.: 7585-39-9, purchased from Wuhan Fuxin Chemical Co., Ltd.

[0038] Methacrylic anhydride, CAS No.: 760-93-0, purchased from Taian Jiangzhou Biotechnology Co., Ltd.

[0039] Thymol, CAS No.: 89-83-8, purchased from Jiangxi Xuesong Natural Medicinal Oil Co., Ltd.

[0040] Example 1

[0041] This embodiment provides a 3D printing gel composition for sports protective pads, comprising the following parts by weight of materials:

[0042] 18 parts of trimethylolpropane trimethacrylate, 30 parts of polyurethane acrylate, 10 parts of acrylated eutectic solvent, 3 parts of methacrylated-β-cyclodextrin inclusion complex loaded with antibacterial agent, 8 parts of amine-modified polyether acrylate, and 2.5 parts of additives.

[0043] The adjuvants include 0.5 parts antioxidant (a mixture of 0.25 parts antioxidant 1010 and 0.25 parts antioxidant 168) and 2.0 parts TPO initiator (i.e., 2,4,6-trimethylbenzoyl-diphenylphosphine oxide).

[0044] The method for preparing the acrylated eutectic solvent is as follows: choline chloride, which acts as a hydrogen bond acceptor, is mixed with hydroxyethyl methacrylate (HEMA), which acts as a hydrogen bond donor, at a molar ratio of 1:2.5. The mixture is then magnetically stirred at 60°C for 1 hour until a transparent and homogeneous eutectic solvent liquid is formed.

[0045] The preparation steps of the methacrylated-β-cyclodextrin inclusion complex loaded with the antibacterial agent include:

[0046] (1) Synthesis of MA-β-CD: 0.01 mol (about 11.35 g) of dried β-cyclodextrin was dissolved in 100 mL of N,N-dimethylformamide (DMF), and 0.11 mol of triethylamine and 0.008 mol of 4-dimethylaminopyridine were added. The mixture was stirred at 300 rpm under nitrogen protection until completely dissolved. The mixture was placed in an ice bath at 0 °C and 0.12 mol of methacrylic anhydride was slowly added dropwise over 2.5 hours. The ice bath was removed and the mixture was stirred at room temperature in the dark for 45 hours. After the reaction was completed, the reaction solution was slowly added dropwise to a large amount of ice-cold deionized water to precipitate the precipitate. The precipitate was filtered and washed three times with deionized water and a small amount of ethanol to remove unreacted acid and solvent. Finally, the mixture was dried in a vacuum drying oven at 40 °C to obtain MA-β-CD.

[0047] (2) Inclusion reaction: The above MA-β-CD was dissolved in a mixed solvent of deionized water and anhydrous ethanol in a volume ratio of 9:1 to prepare a 12% mass fraction solution; thymol (molar ratio of MA-β-CD of 1:1) was pre-dissolved in 10 mL of anhydrous ethanol and then added to the MA-β-CD solution; the mixture was stirred at 500 rpm for 5.5 hours in a constant temperature water bath at 45℃ in the dark; after the reaction was completed, the ethanol in the mixture was removed by a rotary evaporator and then placed in a freeze dryer and vacuum freeze-dried at -50℃ for 45 hours to obtain the methacrylated-β-cyclodextrin inclusion complex loaded with antibacterial agent.

[0048] The method for preparing the 3D-printed gel composition for sports protective pads in this embodiment includes the following steps:

[0049] S1. Heat the polyurethane acrylate to 60°C to make it exhibit good flow dynamics, and under light-protected conditions, add trimethylolpropane trimethacrylate, amine-modified polyether acrylate and methacrylated-β-cyclodextrin inclusion complex loaded with antibacterial agent in sequence, disperse at high speed until completely dissolved, then add acrylated eutectic solvent and stir homogeneously for 20 minutes.

[0050] S2. Then add the antioxidant and TPO initiator in the above proportions, put them into a vacuum degassing machine, and stir and degas for 45 minutes at a temperature of 60℃, a pressure of -0.09MPa and 300rpm. After cooling to room temperature, the 3D printing gel composition resin liquid is obtained.

[0051] like Figure 1 and Figure 2As shown, the sports protective pad prepared using the resin liquid composition of Example 1 was pre-built into a digital 3D model in 3D modeling software based on ergonomic data. Figure 1 As shown, in order to balance lightweight, breathability and isotropic cushioning and shock absorption performance, the model is shaped like a riding seat that is narrower at the front and wider at the rear. Its internal structure is designed as a connected multi-hole hollow lattice structure, while the outer edge of the model retains a continuous solid outline to provide edge support and wear resistance.

[0052] The 3D printing gel composition resin liquid prepared in Example 1 was poured into the feed tank of a DLP (Digital Light Processing) 3D printer with a wavelength of 405 nm. The above-mentioned 3D model slice file was imported, and photopolymerization printing was performed at room temperature. The printing layer thickness was set to 50 μm, the bottom layer exposure time was set to 25-30 seconds to ensure the adhesion of the model on the molding platform, and the exposure time of the regular layers was set to 5-8 seconds. As the molding platform was raised layer by layer, the resin liquid crosslinked and cured under ultraviolet light, gradually constructing a gasket green body with a complex internal lattice structure.

[0053] because Figure 1 The gasket shown has densely packed micro-perforated holes. After printing, the gasket preform with residual liquid resin is removed and completely immersed in anhydrous ethanol cleaning solution. An ultrasonic cleaner is then used for 10 minutes to thoroughly remove uncured resin deep within the lattice holes using ultrasonic cavitation, preventing clogging. After removal, high-pressure compressed air is used to quickly dry any residual solvent inside the lattice network. Finally, the cleaned and dried gasket is placed in a UV secondary curing chamber (irradiation power 200W) and cured at room temperature for a total of 20 minutes with double-sided irradiation. This process ensures complete cross-linking of the unreacted acrylate double bonds within the material, ultimately yielding the gasket shown. Figure 1 The image shows a sports protective pad that combines high elasticity, high tear resistance, and fully unobstructed channels.

[0054] like Figure 1 The complex lattice structure shown not only endows the pad with excellent physical breathability and lightweight characteristics, but more importantly, when athletes sweat profusely, sweat can quickly enter these open macroscopic channels. At this time, the unique eutectic solvent network and cyclodextrin-restricted swelling mechanism of the material in Example 1 are activated. After the material surface absorbs water, it undergoes micro-expansion into the pores, causing the lattice porosity to adaptively narrow, thereby providing stronger aerodynamic damping and structural support. The more sweat, the stronger the support. At the same time, the sweat washes over the lattice channels, triggering the competitive release of thymol in the cyclodextrin cavities, achieving encapsulated, all-round long-lasting antibacterial and deodorizing effects.

[0055] Example 2

[0056] This embodiment provides a 3D printing gel composition for sports protective pads, comprising the following parts by weight of materials:

[0057] 10 parts of trimethylolpropane trimethacrylate, 25 parts of polyurethane acrylate, 5 parts of acrylated eutectic solvent, 1 part of methacrylated-β-cyclodextrin inclusion complex loaded with antibacterial agent, 5 parts of amine-modified polyether acrylate, and 0.5 parts of additives.

[0058] The additives include 0.1 parts antioxidant (antioxidant 1010 and 168 are mixed in equal mass ratios) and 0.4 parts TPO initiator.

[0059] The method for preparing the acrylated eutectic solvent is as follows: choline chloride and acrylic acid are mixed in a molar ratio of 1:2 and magnetically stirred at 55°C until a transparent and homogeneous eutectic solvent liquid is formed.

[0060] The inclusion complex was prepared in the same way as in Example 1, except that in the MA-β-CD synthesis reaction, the molar ratio of β-cyclodextrin, triethylamine, 4-dimethylaminopyridine and methacrylic anhydride was controlled at 1:10:0.5:10, and the reaction time was 40 hours; the inclusion process was carried out at a water bath temperature of 40°C for 5 hours, followed by freeze drying for 40 hours.

[0061] The preparation method steps in this embodiment include:

[0062] S1. Heat the polyurethane acrylate to 60°C to make it exhibit good flow dynamics, and under light-protected conditions, add trimethylolpropane trimethacrylate, amine-modified polyether acrylate and methacrylated-β-cyclodextrin inclusion complex loaded with antibacterial agent in sequence, disperse at high speed until completely dissolved, then add acrylated eutectic solvent and stir homogeneously for 20 minutes.

[0063] S2. Add the additives, degas at 55℃ and -0.08MPa for 30 minutes, and cool to room temperature to obtain the final product.

[0064] Example 3

[0065] This embodiment provides a 3D printing gel composition for sports protective pads, comprising the following parts by weight of materials:

[0066] 25 parts of trimethylolpropane trimethacrylate, 35 parts of polyurethane acrylate, 15 parts of acrylated eutectic solvent, 5 parts of methacrylated-β-cyclodextrin inclusion complex loaded with antibacterial agent, 10 parts of amine-modified polyether acrylate, and 5 parts of additives.

[0067] The additives include 1 part antioxidant (antioxidant 1010 and 168 are mixed in equal mass ratio) and 4 parts TPO initiator.

[0068] The method for preparing the acrylated eutectic solvent is as follows: choline chloride and a hydrogen bond donor (composed of acrylic acid and hydroxyethyl methacrylate in a mass ratio of 1:1) are mixed in a molar ratio of 1:3 and magnetically stirred at 65°C until a transparent and homogeneous eutectic solvent liquid is formed.

[0069] The inclusion complex was prepared in the same way as in Example 1, except that in the MA-β-CD synthesis reaction, the molar ratio of β-cyclodextrin, triethylamine, 4-dimethylaminopyridine and methacrylic anhydride was controlled at 1:12:1.0:15, and the reaction time was 50 hours; the inclusion process was carried out at a water bath temperature of 50°C for 6 hours, followed by freeze drying for 50 hours.

[0070] The preparation method steps in this embodiment include:

[0071] S1. Heat the polyurethane acrylate to 60°C to make it exhibit good flow dynamics, and under light-protected conditions, add trimethylolpropane trimethacrylate, amine-modified polyether acrylate and methacrylated-β-cyclodextrin inclusion complex loaded with antibacterial agent in sequence, disperse at high speed until completely dissolved, then add acrylated eutectic solvent and stir homogeneously for 20 minutes.

[0072] S2. Add the additives, degas at 65℃ and -0.1MPa for 60 minutes, and cool to room temperature to obtain the final product.

[0073] The content of Examples 2 and 3 is based on Example 1, and the parts not described are the same as in Example 1.

[0074] Comparative Example 1

[0075] The only difference from Example 1 is that the eutectic solvent for acrylate esterification is not added to the formulation; instead, an equal weight (10 parts) of trimethylolpropane trimethacrylate is used, i.e., 28 parts of trimethylolpropane trimethacrylate. The remaining components and preparation methods are exactly the same as in Example 1.

[0076] Comparative Example 2

[0077] The only difference from Example 1 is that in the preparation of the eutectic solvent for acrylate esterification, the heating and hydrogen bonding process was not used. Instead, choline chloride powder and hydroxyethyl methacrylate were directly mixed physically, forcibly dispersed by ultrasonication, and then added directly to the resin solution. The remaining components and preparation methods are exactly the same.

[0078] Preparation method:

[0079] S1. Choline chloride powder and hydroxyethyl methacrylate were mixed at room temperature according to the ratio of Example 1, and then forcibly ultrasonically dispersed for 20 minutes, resulting in a turbid suspension without forming a transparent eutectic.

[0080] S2. Heat the polyurethane acrylate to 60°C, and add trimethylolpropane trimethacrylate, amine-modified polyether acrylate, and methacrylated-β-cyclodextrin inclusion complex containing antibacterial agent under the protection of light. After high-speed dispersion, add the above turbid suspension and stir for 20 minutes.

[0081] S3. Add the additives and degas at 60℃ and -0.09MPa for 45 minutes. Cool to room temperature to obtain the final product.

[0082] Comparative Example 3

[0083] The only difference from Example 1 is that the acrylate eutectic solvent of the present invention is not used; instead, 3 parts of commercially available azodicarbonamide are added to simulate the 3D printed cushioning material that uses foaming to create pores in the prior art.

[0084] The specific weight parts of the materials are as follows: 18 parts of trimethylolpropane trimethacrylate, 30 parts of polyurethane acrylate, 3 parts of methacrylated-β-cyclodextrin inclusion complex loaded with antibacterial agent, 8 parts of amine-modified polyether acrylate, 3 parts of azodicarbonamide, and 2.5 parts of additives.

[0085] Preparation method:

[0086] S1. Heat the polyurethane acrylate to 60°C, and add trimethylolpropane trimethacrylate, amine-modified polyether acrylate, methacrylated-β-cyclodextrin inclusion complex loaded with antibacterial agent and AC foaming agent in sequence under the protection of light, and disperse at high speed for 20 minutes.

[0087] S2. After adding additives and degassing, a resin solution is obtained. After 3D printing, a heat treatment process at 150°C is added to activate the foaming agent to generate pores.

[0088] Comparative Example 4

[0089] The only difference from Example 1 is that the formulation does not contain the methacrylated-β-cyclodextrin inclusion complex carrying the antibacterial agent, but instead uses an equal weight of trimethylolpropane trimethacrylate.

[0090] The specific weight parts of the materials are: 21 parts of trimethylolpropane trimethacrylate (original 18 parts + 3 parts of replacement), 30 parts of polyurethane acrylate, 10 parts of acrylated eutectic solvent, 8 parts of amine-modified polyether acrylate, and 2.5 parts of additives.

[0091] Preparation method: S1. Prepare the acrylated eutectic solvent in advance according to the method of Example 1; S2. Heat the polyurethane acrylate to 60°C, add trimethylolpropane trimethacrylate and amine-modified polyether acrylate sequentially under the protection of light, then add the pre-prepared acrylated eutectic solvent and stir for 20 minutes; S3. Add the additives, and perform degassing treatment at 60°C and -0.09MPa for 45 minutes. After cooling to room temperature, the product is obtained.

[0092] Comparative Example 5

[0093] The only difference from Example 1 is that the synthesized "methacrylated-β-cyclodextrin inclusion complex loaded with antibacterial agent" is not used, but instead, equimolar amounts of ordinary unmodified β-cyclodextrin and thymol are added directly.

[0094] Experiment 1: Performance Testing

[0095] The resin liquids prepared in Examples 1-3 and Comparative Examples 1-5 were printed using a DLP 3D printer (wavelength 405nm).

[0096] To ensure the reproducibility of test results, the following uniform printing and post-processing parameters were used for all groups in this experiment:

[0097] (1) Printing parameter settings: At room temperature of 25±2℃, the printing layer thickness is set to 50μm; in order to ensure the adhesion of the model on the construction stage, the bottom layer exposure time is set to 25 seconds and the number of bottom layers is 3; the exposure time of the regular layer (subsequent layer) is set to 5 seconds and the lifting speed is 120 mm / min.

[0098] (2) Setting the size of the printed model: During the above printing process, the following two standard models are printed at once:

[0099] Model A (for tear resistance test): Right-angled uncut test strip conforming to GB / T 529-2008 standard, with a thickness set at 2.0±0.2 mm.

[0100] Model B (sports pad model with micro-vents, used for fatigue testing, sweat response and antibacterial testing): The overall three-dimensional dimensions are a cylindrical block with a diameter of 50 mm and a thickness of 25 mm; its cross-section has an array of micropores evenly distributed along the thickness direction (Z-axis);

[0101] (3) Post-processing: After printing, the molded part attached to the construction stage is removed and completely immersed in anhydrous ethanol. It is then cleaned with an ultrasonic cleaner for 5 minutes to thoroughly remove the uncured resin liquid remaining on the surface and in the micro air vents. Subsequently, compressed air is used to dry the residual solvent on the surface and in the vents. Finally, the molded part is placed in a UV secondary curing chamber (light source wavelength 405nm, irradiation power 200W) and subjected to a secondary UV post-curing treatment at room temperature for 15 minutes (7.5 minutes on each side) to ensure that the polymer cross-linking network reaches a fully cured state.

[0102] The molded parts (model A and model B) after the above processing were subjected to the following tests:

[0103] Tear resistance: In accordance with GB / T 529-2008 standard, right-angled uncut test strips were used for testing. Model A was tested using an electronic universal testing machine at a tensile speed of 500 mm / min.

[0104] High-frequency fatigue test (springback retention rate): Model B is placed on a fatigue testing machine and subjected to 30% compression deformation at a frequency of 5Hz. After continuous compression for 50,000 cycles, it is allowed to rest for 30 minutes, and its thickness retention rate is measured.

[0105] Sweat Adaptive Response Test (Support Force Increase Rate): The initial compression modulus (M1) of model B in a dry state was measured using a compression testing machine; then it was completely immersed in simulated sweat (0.5wt% NaCl aqueous solution) for 30 minutes, removed, and the surface moisture was wiped off before measuring the compression modulus (M2) again. The support force increase rate was calculated as (M2 - M1) / M1 × 100%.

[0106] Sweat antibacterial rate test: Referring to GB / T 20944.3-2008 (vibration method), model B was cut into 5mm×5mm fragments totaling 0.75g and placed in an inoculation with Staphylococcus aureus (representing the main odor-producing bacteria in sweat, with a concentration of approximately 3×10⁻⁶). 5 The antibacterial rate was calculated after 50 mL of simulated sweat (CFU / mL) was subjected to shaking at 37°C for 24 hours.

[0107] Five samples were tested in each group, and the average value was taken. The results are shown in Table 1 below:

[0108] Based on the above data, it can be seen that the molded parts printed in Examples 1-3 possess both extremely high tear strength (all above 48 kN / m) and fatigue resilience retention. Especially in the sweat response test, the support strength of Examples 1-3 increased significantly by more than 24% after water absorption, and the antibacterial rate under the sweat-triggered slow-release mechanism reached over 96%. This fully verifies the synergistic effect of the acrylated eutectic solvent (DES) and the methacrylated-β-cyclodextrin inclusion complex carrying the antibacterial agent in this invention.

[0109] Comparative Example 1 lacked a eutectic solvent. Although it exhibited excellent mechanical properties due to the action of the MA-β-CD macrocycle, the cross-linked network could not absorb water and swell slightly after encountering sweat, resulting in a slight decrease in support (-1.5%), completely losing the adaptive function of the present invention.

[0110] Comparative Example 2 used physical mixing, which failed to form a deep eutectic hydrogen bond network. This caused choline chloride to agglomerate and precipitate in the photocured network, severely damaging the uniformity of the crosslinked network and resulting in a sharp drop in tear strength and resilience.

[0111] Comparative Example 3 simulates the existing foamed 3D resin in the background technology. Due to the destruction of the internal cross-linking network by pores, its tear strength (only 18.5 kN / m) and fatigue resistance are extremely poor (severe collapse), and it is completely unable to withstand the high-frequency shear force during cycling.

[0112] Comparing Example 1 and Comparative Example 4, it can be seen that when the formulation contains only a eutectic solvent and lacks cyclodextrin carrying antibacterial agents, the material undergoes macroscopic swelling and plasticization due to the loss of the topological anchoring constraint of the organic rigid macrocyclic core and the release mechanism of the targeted antibacterial substance. This results in the overall softening of the pad (a 12.6% decrease in support) and the absence of sweat antibacterial and deodorizing functions (antibacterial rate of only 15.2%). This proves that simply adding a water-absorbing solvent cannot solve the needs of sports protective pads; MA-β-CD is necessary to stimulate a dual response of water absorption hardening and intelligent antibacterial properties.

[0113] Comparing Example 1 and Comparative Example 5, it can be seen that when ordinary non-polymerized β-cyclodextrin is added directly, it cannot covalently crosslink with the resin matrix. This not only acts as a stress concentration point that disrupts the network, leading to a significant decrease in mechanical and fatigue properties (only 85.4% retention rate), but also fails to generate crosslinked network topological constraints, causing the pad to macroscopically swell upon contact with sweat (a 10.8% decrease in support force). Simultaneously, free thymol, without encapsulation protection, is largely lost during printing and post-processing cleaning, causing the antibacterial rate to plummet to 72.5%.

[0114] Finally, it should be noted that the above embodiments and comparative examples are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention; those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention; and all technical solutions and improvements that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A 3D printed gel state composition for use in a sports protective pad, characterized in that, The product comprises the following materials in parts by weight: 10-25 parts of trimethylolpropane trimethacrylate, 25-35 parts of polyurethane acrylate, 5-15 parts of acrylated eutectic solvent, 1-5 parts of methacrylated-β-cyclodextrin inclusion complex loaded with antibacterial agent, 5-10 parts of amine-modified polyether acrylate, and 0.1-5 parts of additives.

2. The 3D-printed gel composition for sports protective pads according to claim 1, characterized in that, The acrylate eutectic solvent is a transparent liquid monomer formed at room temperature by strong hydrogen bonding between a hydrogen bond acceptor and a hydrogen bond donor containing polymerizable double bonds.

3. The 3D-printed gel composition for sports protective pads according to claim 2, characterized in that, The hydrogen bond acceptor is choline chloride, and the hydrogen bond donor containing polymerizable double bonds includes acrylic acid and / or hydroxyethyl methacrylate.

4. The 3D-printed gel composition for sports protective pads according to claim 3, characterized in that, The method for preparing the acrylated eutectic solvent includes: mixing hydrogen bond acceptors and hydrogen bond donors in a molar ratio of 1:2-3, and magnetically stirring at 55-65°C until a transparent and homogeneous eutectic solvent liquid is formed.

5. The 3D-printed gel composition for sports protective pads according to claim 1, characterized in that, The method for preparing the methacrylated-β-cyclodextrin inclusion complex loaded with antibacterial agent includes: dissolving methacrylated-β-cyclodextrin in a mixed solvent of deionized water and anhydrous ethanol to prepare an MA-β-CD solution; pre-dissolving thymol in anhydrous ethanol and then adding it to the MA-β-CD solution; continuously stirring and incorporating the antibacterial agent in a constant temperature water bath at 40-50℃ in the dark for 5-6 hours; after the reaction is completed, removing the ethanol from the mixture using a rotary evaporator, and then freeze-drying to obtain the methacrylated-β-cyclodextrin inclusion complex loaded with antibacterial agent.

6. The 3D-printed gel composition for sports protective pads according to claim 5, characterized in that, The preparation method of the methacrylated β-cyclodextrin includes: (1) Dissolve β-cyclodextrin in N,N-dimethylformamide, add triethylamine and 4-dimethylaminopyridine, and stir under nitrogen protection until completely dissolved; (2) Place the reaction system in an ice-water bath at 0-5℃ and slowly add methacrylic anhydride dropwise over a period of 2-3 hours; then remove the ice bath and continue to stir the reaction magnetically at room temperature in the dark for 40-50 hours. (3) After the reaction is complete, the reaction solution is slowly dripped into a large amount of ice-cold deionized water to precipitate the precipitate; the precipitate is filtered, washed and dried to obtain the final product.

7. The 3D-printed gel composition for sports protective pads according to claim 6, characterized in that, The molar ratio of β-cyclodextrin, triethylamine, 4-dimethylaminopyridine to methacrylic anhydride is 1:(10-12):(0.5-1.0):(10-15).

8. The 3D-printed gel composition for sports protective pads according to claim 1, characterized in that, The adjuvant comprises an antioxidant and an initiator in a weight ratio of 1:4; wherein the antioxidant comprises antioxidant 1010 and antioxidant 168; and the initiator is a TPO initiator.

9. The method for preparing a 3D-printed gel composition for sports protective pads as described in any one of claims 1-8, characterized in that step... include: S1. The polyurethane acrylate is heated to a fluid state, and under light-protected conditions, trimethylolpropane trimethacrylate, amine-modified polyether acrylate, and methacrylated-β-cyclodextrin inclusion complex loaded with antibacterial agent are added sequentially and dispersed at high speed until completely dissolved. Then, acrylated eutectic solvent is added and homogeneous stirring is performed. S2. Add antioxidants and initiator additives, stir and degas under negative pressure, and cool to room temperature to obtain the final product.

10. The method for preparing the 3D-printed gel composition for sports protective pads according to claim 9, characterized in that, The degassing treatment is performed at a temperature of 55℃-65℃, a pressure of -0.08MPa to -0.1MPa, and a time of 30-60 minutes.

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