Self-adhesive bandage for knee joint and preparation method of self-adhesive bandage

Abstract

The invention belongs to the technical field of medical bandages, and discloses a self-adhesive bandage for knee joints and a preparation method thereof.The self-adhesive bandage comprises a supporting layer, a composite antibacterial self-adhesive layer and an anti-adhesive layer which are sequentially arranged from bottom to top; the supporting layer is prepared from the following raw materials in parts by weight: 15-20 parts of a bidirectional polymer, 3-5 parts of carboxymethyl chitosan-nano-silver composite particles, 8-12 parts of a polyurethane elastomer and 0.3-0.5 part of an antioxidant; the composite antibacterial self-adhesive layer is prepared from the following raw materials in parts by weight: 20-25 parts of a silicone pressure-sensitive adhesive, 3-5 parts of rosin-based tackifying resin and 1-2 parts of a polyethylene glycol softening agent; the anti-sticking layer is a fluorine-silicon release film, and the fluorine-silicon release film is prepared from the following raw materials in parts by weight: 10-15 parts of a fluorine-silicon polymer, 20-30 parts of toluene, 0.5-1 part of a cross-linking agent and 0.1-0.3 part of a catalyst; the use amount of the fluorosilicone release film is 1-2 pieces matched with the area of the composite antibacterial self-adhesive layer; the problems that in the prior art, a knee joint bandage is insufficient in elasticity, lack of antibiosis, unstable in self-adhesion and poor in fitting performance are solved.

Description

Technical Field

[0001] This invention relates to the field of medical bandage technology, specifically to a self-adhesive bandage for the knee joint and its preparation method. Background Technology

[0002] The knee joint, as the joint with the greatest weight-bearing and activity level in the human body, is prone to sports injuries, postoperative rehabilitation, or chronic strain, requiring external bandaging and fixation. Existing knee bandages mainly suffer from the following problems: First, insufficient elastic support; traditional cotton or synthetic fiber bandages lack dynamic adaptability and cannot adjust their fit according to knee flexion and extension, easily loosening or compressing blood circulation with long-term use. Second, lack of antibacterial properties; prolonged contact between the bandage and skin easily breeds bacteria, causing skin inflammation, especially posing an infection risk for postoperative patients. Third, poor self-adhesive stability; some self-adhesive bandages use rubber-based pressure-sensitive adhesives, whose adhesiveness is easily affected by sweat and tends to leave adhesive residue on the skin. Fourth, poor compatibility of the release layer; the peel force between ordinary polyethylene release film and the self-adhesive layer is uneven, either making peeling difficult or damaging the adhesive layer after peeling.

[0003] Furthermore, existing bandages often fail to consider the anatomical structure and activity characteristics of the knee joint, lack shape memory function, and cannot restore their initial fit after flexion and extension, resulting in a continuous decline in support effectiveness. Therefore, developing a knee-specific bandage that combines high elasticity, dynamic fit, long-lasting antibacterial properties, stable self-adhesion, and easy peeling has become an urgent technical need to be addressed in this field. Summary of the Invention

[0004] The present invention aims to provide a self-adhesive bandage for the knee joint and a method for preparing the same, in order to solve the problems of insufficient elasticity, lack of antibacterial properties, unstable self-adhesion, and poor fit of existing knee joint bandages.

[0005] To achieve the above objectives, the present invention provides the following technical solution: The technical solution provided by this invention is: A self-adhesive bandage for the knee joint includes a support layer, a composite antibacterial self-adhesive layer, and an anti-adhesive layer arranged sequentially from bottom to top. The support layer is prepared from the following raw materials in the following proportions: 15-20 parts of biaxial polymer, 3-5 parts of carboxymethyl chitosan-silver nanoparticles, 8-12 parts of polyurethane elastomer, and 0.3-0.5 parts of antioxidant. The composite antibacterial self-adhesive layer is prepared from the following raw materials in the following proportions: 20-25 parts silicone pressure-sensitive adhesive, 3-5 parts rosin-based tackifying resin, and 1-2 parts polyethylene glycol softener. The anti-stick layer is a fluorosilicone release film, which is prepared from the following raw materials in parts: 10-15 parts of fluorosilicone polymer, 20-30 parts of toluene, 0.5-1 parts of crosslinking agent, and 0.1-0.3 parts of catalyst; The amount of fluorosilicone release film used is 1-2 sheets, matching the area of ​​the composite antibacterial self-adhesive layer.

[0006] Furthermore, the preparation method of the fluorosilicone release film includes: dissolving 10-15 parts of fluorosilicone polymer in 20-30 parts of toluene, adding 0.5-1 parts of crosslinking agent and 0.1-0.3 parts of catalyst, stirring evenly, and then coating it on a polyester film with a coating thickness of 0.5-1 μm, and curing it at 120-150℃ for 10-15 minutes to form a release film.

[0007] Furthermore, the bidirectional polymer is an interpenetrating network structure formed by crystalline cross-linked polyurethane and SBS elastomer. Its preparation method includes: mixing polyurethane prepolymer and SBS elastomer at a mass ratio of 3:1, adding dibutyltin dilaurate catalyst (0.5% of the total mass) at 60°C, and obtaining it through a two-step cross-linking reaction.

[0008] Furthermore, the preparation method of carboxymethyl chitosan-silver nanoparticles includes: dissolving 3-7g of carboxymethyl chitosan in 80-120mL of 2wt% acetic acid solution, adding 0.8-1.2mL of 0.1mol / L silver nitrate solution, stirring at 25-35℃ for 25-35 minutes, then adding 8-12mL of 0.05mol / L vanillin ethanol solution, continuing the reaction for 2.5-3.5 hours, and then freeze-drying to obtain composite particles with an average particle size of 40-50nm.

[0009] Furthermore, the support layer also includes a nonwoven fabric substrate modified with carboxymethyl chitosan. The modification method is as follows: the nonwoven fabric is soaked in a 5wt% carboxymethyl chitosan aqueous solution for 30 minutes and then dried at 80°C to form an antibacterial reinforcing layer.

[0010] A method for preparing a self-adhesive bandage for the knee joint includes the following steps: S1: Preparation of modified nonwoven fabric substrate: The nonwoven fabric was immersed in a 5wt% carboxymethyl chitosan aqueous solution for 30 minutes, and dried at 80℃ until the moisture content was ≤5%, resulting in a surface carboxymethyl chitosan loading of 1.2-1.5 mg / cm³. 2 Modified nonwoven fabric substrate; S2: Preparation of support layer slurry: Weigh 15-20 parts of biaxial polymer, 3-5 parts of carboxymethyl chitosan-silver nanoparticles, 8-12 parts of polyurethane elastomer, and 0.3-0.5 parts of antioxidant according to the specified proportions, add them to a twin-screw extruder, melt-blend at 120°C for 15 minutes, extrude and granulate, and then dissolve in dichloromethane to prepare a slurry with a solid content of 30%. S3: Composite support layer: The slurry obtained in S2 is coated onto the surface of the modified nonwoven fabric substrate prepared in S1 (coating thickness 0.3-0.4 mm), and dried at 80°C for 10 minutes to form a support layer; S4: Preparation of composite antibacterial self-adhesive layer slurry: Weigh 20-25 parts of silicone pressure-sensitive adhesive, 3-5 parts of rosin-based tackifying resin, and 1-2 parts of polyethylene glycol softener according to the specified proportions, add them to a planetary mixer, and stir at 200 r / min for 20 minutes at 50℃. S5: Composite self-adhesive layer and anti-adhesive layer: The slurry obtained in S4 is coated on the surface of the support layer (coating thickness 0.15-0.25mm), and after standing at room temperature for 5 minutes, a fluorosilicone release film is covered, and a pressure of 0.15MPa is applied for 3 minutes for lamination; S6: Cutting and shaping: The composite bandage is cut into finished products with a width of 7-12cm and a length of 120-180cm using a laser cutting machine, with the cutting accuracy controlled within ±0.05cm.

[0011] Furthermore, the preparation of the modified nonwoven fabric substrate in S1 was carried out in a clean environment with a humidity of ≤60%.

[0012] Furthermore, the composite process in S5 is carried out in a cleanroom environment with humidity ≤50%.

[0013] Furthermore, the screw speed of the twin-screw extruder in S2 is 300 r / min.

[0014] The beneficial effects of this technical solution are: (1) The support layer is composed of bidirectional polymer, carboxymethyl chitosan-silver nanoparticles and polyurethane elastomer as core components. The components complement each other in function. The structure itself has the characteristics of both rigidity and toughness and can serve as the mechanical skeleton of the support layer. In the carboxymethyl chitosan-silver nanoparticles, carboxymethyl chitosan has natural biocompatibility and hydrophilicity, which can form a stable bond with silver nanoparticles. This not only prevents the aggregation of silver nanoparticles, but also gives the support layer long-term antibacterial ability by taking advantage of the antibacterial properties of silver nanoparticles. The polyurethane elastomer has excellent elastic recovery and can fill the gaps in the network of the bidirectional polymer to further optimize the elastic performance of the support layer. The antioxidants can inhibit the oxidative aging of each polymer component during processing and use, and extend the performance stability period of the support layer. At the same time, the support layer introduces a non-woven fabric substrate modified with carboxymethyl chitosan. The antibacterial reinforcement layer formed by carboxymethyl chitosan on the surface of the non-woven fabric is superimposed with the antibacterial effect of the composite particles. The porous structure of the non-woven fabric can improve the breathability of the support layer and the skin, and avoid the stuffy environment of the bandage.

[0015] (2) The bidirectional polymer in the support layer is the key component for achieving dynamic adaptation of the knee joint. When subjected to external force stretching, it can undergo elastic deformation and recover its initial shape by means of shape memory characteristics after deformation, which perfectly matches the dynamic deformation requirements of the knee joint during flexion and extension, avoiding the problem of looseness or tightness of traditional bandages. The addition of polyurethane elastomer further enhances the elastic recovery ability of the support layer. Its flexible molecular chain structure can absorb external force during stretching, reduce the pressure on the knee joint, and ensure that the bandage can still maintain sufficient support after long-term wear.

[0016] (3) The composite antibacterial self-adhesive layer uses silicone pressure-sensitive adhesive as the base adhesive. Silicone pressure-sensitive adhesive itself has excellent temperature resistance and skin compatibility. The siloxane bonds in its molecular structure can remain stable in a wide temperature range, avoiding the problems of low-temperature delamination and high-temperature residual adhesive residue. At the same time, it reduces skin irritation and lowers the risk of allergies. Rosin-based tackifying resin is used as the tackifying component. Its natural resin structure can interact with the molecular chain of silicone pressure-sensitive adhesive, improving the initial tack and holding power of the self-adhesive layer. The oleophilicity of the rosin-based component can improve the wettability of the self-adhesive layer to the surface of the support layer, enhancing the bonding strength between the self-adhesive layer and the support layer. The addition of polyethylene glycol softener can improve the adhesion of the self-adhesive layer by adjusting the hardness of the self-adhesive layer, so that it can better adapt to the microstructure of the support layer surface. At the same time, the water solubility of polyethylene glycol can further improve the skin compatibility of the self-adhesive layer and reduce the discomfort of prolonged adhesion to the skin.

[0017] (4) The anti-adhesive layer uses fluorosilicone release film. Its core component, fluorosilicone polymer, has extremely low surface energy, which can effectively reduce the adhesion to the composite antibacterial self-adhesive layer, ensuring that the anti-adhesive layer can be smoothly peeled off during use without damaging the structural integrity of the self-adhesive layer. Toluene, as a solvent, can fully dissolve and disperse the fluorosilicone polymer. With the help of crosslinking agent and catalyst, the fluorosilicone polymer forms a uniform and dense coating on the surface of the polyester film. The coating thickness is controlled at 0.5-1μm. This thickness can ensure the release effect without causing the anti-adhesive layer to become stiff due to excessive coating thickness. The addition of crosslinking agent can enable the fluorosilicone polymer molecular chain to form a crosslinked structure, improve the friction resistance and temperature resistance of the release film, and avoid damage to the release film during storage or transportation. The catalyst can promote the full progress of the crosslinking reaction, ensure the curing effect of the release film coating, and thus ensure the performance stability of the release film under different environments. The amount of fluorosilicone release film is matched with the area of ​​the composite antibacterial self-adhesive layer, and a design of 1-2 sheets is adopted. Single-sided or double-sided protection can be selected according to the usage requirements, flexibly adapting to different storage and usage scenarios. Attached Figure Description

[0018] Figure 1 This diagram illustrates the preparation steps of a self-adhesive bandage for the knee joint and its preparation method proposed in this invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The specific implementation process is as follows: Preliminary preparations: 1. Preparation of bidirectional polymers: Add 300g of polyurethane prepolymer (TDI type) and 100g of SBS elastomer (mass ratio 3:1) to a high-speed mixer and stir at 60℃ for 10min; add 2g of dibutyltin dilaurate catalyst (0.5% of the total mass of 400g), transfer to a reactor, crosslink at 80℃ for 1h, then raise the temperature to 100℃ for 2h; cool to room temperature, pulverize to a particle size of 1-2mm, and set aside.

[0021] 2. Preparation of carboxymethyl chitosan-silver nanoparticles: Take 5g of carboxymethyl chitosan and dissolve it in 100mL of 2wt% acetic acid solution (2g acetic acid + 98g deionized water), and stir until transparent; add 1mL of 0.1mol / L silver nitrate solution and stir magnetically at 30℃ for 30min; add 10mL of 0.05mol / L vanillin ethanol solution dropwise and continue stirring for 3h; transfer the mixture to a freeze dryer and freeze dry at -40℃ for 24h, and collect the composite microparticles with a particle size of 40-50nm for later use.

[0022] 3. Preparation of fluorosilicone release film: Take 12g of fluorosilicone polymer (fluorosilicone polymer is fluoroalkyl polyether modified polysiloxane) and 25g of toluene, put them into a beaker, and stir for 10min until dissolved; add 0.8g of crosslinking agent (triethoxysilane) and 0.2g of catalyst (dibutyltin dilaurate), and continue stirring for 30min; use a coating machine to coat the solution onto the surface of a 25μm thick polyester film, with a coating thickness of 0.8μm, cure in an oven at 135℃ for 12min, and after cooling, obtain a fluorosilicone release film for later use.

[0023] Example 1: Please see Figure 1 The present invention provides a technical solution: a self-adhesive bandage for the knee joint and a method for preparing the same, comprising the following raw material formula: Support layer: 18g biaxial polymer, 4g carboxymethyl chitosan-silver nanoparticles, 10g polyurethane elastomer (1185A, Shore A hardness 80A), 0.4g antioxidant 1010; modified nonwoven fabric substrate (100cm²). 2 Dosage: 6g Composite antibacterial self-adhesive layer: silicone pressure-sensitive adhesive (Wacker SILPURAN® 2114) 22g, rosin-based tackifying resin (Foral 85) 4g, polyethylene glycol softener (polyethylene glycol 400) 1.5g; Anti-stick layer: 1 sheet of fluorosilicone release film; The preparation steps are as follows: S1: Preparation of modified nonwoven substrate Take 100cm 2 Polyester nonwoven fabric was soaked in 50 mL of 5 wt% carboxymethyl chitosan aqueous solution (2.5 g carboxymethyl chitosan + 47.5 g water) for 30 minutes, then removed and dried at 80℃ for 15 minutes. The moisture content was measured to be 4.2%, and the carboxymethyl chitosan loading was 1.3 mg / cm³. 2 ; S2: Preparation of support layer slurry 18g of biaxial polymer, 4g of carboxymethyl chitosan-silver nanoparticles, 10g of polyurethane elastomer, and 0.4g of antioxidant 1010 were fed into a twin-screw extruder (300r / min), melt-blended at 120℃ for 15min, and then extruded and granulated. 20g of the granules were dissolved in 46.7g of dichloromethane (30% solid content) and stirred for 30min until transparent to obtain a slurry. S3: Composite support layer The slurry was applied to the surface of the modified nonwoven fabric with a doctor blade to a thickness of 0.35 mm. After drying at 80°C for 10 min, the thickness of the support layer after drying was 0.18 mm, with no bubbles or cracks. S4: Preparation of self-adhesive layer paste 22g of silicone pressure-sensitive adhesive, 4g of rosin-based tackifying resin (Foral 85), and 1.5g of polyethylene glycol softener (polyethylene glycol 400) were added to a planetary mixer and stirred at 50℃ and 200r / min for 20min to obtain a uniform slurry. S5: Composite self-adhesive layer and anti-adhesive layer Self-adhesive layer, 0.2mm thick; let stand at room temperature for 5 minutes, then cover 100cm. 2 Fluorosilicone release film, laminated under 0.15MPa pressure for 3 minutes, without wrinkles or bubbles; S6: Cutting and shaping Laser-cut to 10cm×150cm finished products with an accuracy of ±0.03cm, then packaged and stored away from light; This embodiment uses the intermediate formula of the claims, and the parameters of each step strictly follow the technical solution. The load and moisture content of the modified nonwoven fabric substrate meet the standards. The solid content of the support layer slurry is precisely controlled at 30%, and there are no bubbles after coating, indicating that the twin-screw mixing is uniform. The self-adhesive layer slurry does not separate after stirring, and the peel strength is stable at 1.8N / 25mm, which meets the requirements for repeated bonding. The release force is 7.5g / 25mm, which can be easily peeled by hand.

[0024] Test Project Test methods Test Results Elastic recovery rate Stretch to 150% of its original length, hold for 5 minutes, then measure. 96.5% Elongation at break Universal tensile testing machine, tensile speed 50mm / min 320% Antibacterial rate (E. coli) Inhibition loop method, incubate for 24 hours 99.2% Peel strength Peeling speed 300 mm / min, 25 mm wide sample 1.8N / 25mm Release force Peeling speed 300 mm / min, 25 mm wide sample 7.5g / 25mm Skin irritation Volunteers applied the patches for 24 hours and their skin reactions were observed. No redness, swelling, or itching Example 2: Please see Figure 1 The present invention provides a technical solution: a self-adhesive bandage for the knee joint and a method for preparing the same, comprising the following raw material formula: Support layer: 15g biaxial polymer, 3g carboxymethyl chitosan-silver nanoparticles, 8g polyurethane elastomer (1185A, Shore A hardness 70A), 0.3g antioxidant 1010; modified nonwoven fabric substrate (100cm²). 2 Dosage: 5g Composite antibacterial self-adhesive layer: 20g silicone pressure-sensitive adhesive (MG 7-9850), 3g rosin-based tackifying resin (Foral 85), 1g polyethylene glycol softener (polyethylene glycol 400); Anti-stick layer: 1 sheet of fluorosilicone release film; The preparation steps are as follows: Same as in Example 1, except that: S1: Modified nonwoven fabric substrate: 100cm 2 Nonwoven fabric, dried at 80℃ for 15 min with 45 mL of 5 wt% carboxymethyl chitosan aqueous solution, has a moisture content of 4.8% and a loading of 1.2 mg / cm³. 2 ; S2: Support layer slurry: 15g biaxial polymer + 3g carboxymethyl chitosan-silver nanocomposite microparticles + 8g polyurethane elastomer (1185A, Shore hardness 70A) + 0.3g antioxidant 1010, mixed by twin-screw extruder at 120℃ for 15min; 15g particles dissolved in 35g dichloromethane (solid content 30%). S3: Composite support layer: Coating thickness 0.3mm, dried at 80℃ for 10min, thickness after drying 0.15mm; S4: Self-adhesive layer paste: 20g silicone pressure-sensitive adhesive (MG 7-9850) + 3g rosin-based tackifying resin (Foral 85) + 1g polyethylene glycol softener (polyethylene glycol 400), stir at 50℃ and 200r / min for 20min; S5: Composite anti-adhesive layer: self-adhesive layer coating thickness 0.15mm, 0.15MPa lamination for 3min; S6: Cutting: Finished product 8cm×120cm, accuracy ±0.04cm; This embodiment uses the lower limit formulation of the support layer raw materials. Although the amount of bidirectional polymer and polyurethane is reduced, the elastic recovery rate still reaches 95.2% and the elongation at break is 290%, which meets the needs of knee joint movement support. The amount of composite microparticles is 3g (corresponding to a silver ion content of 0.0065g), and the antibacterial rate still reaches 98.8%, indicating that a trace amount of nano silver can achieve long-term antibacterial effect. Under the lower limit dosage of the self-adhesive layer raw materials, the peel strength is 1.5N / 25mm, with no glue residue, which meets the usage standards.

[0025] Test Project Test Results Elastic recovery rate 95.2% Elongation at break 290% Antibacterial rate (Staphylococcus aureus) 98.8% Peel strength 1.5N / 25mm Release force 6.8g / 25mm Example 3: Please see Figure 1 The present invention provides a technical solution: a self-adhesive bandage for the knee joint and a method for preparing the same, comprising the following raw material formula: Support layer: 20g biaxial polymer, 5g carboxymethyl chitosan-silver nanoparticles, 12g polyurethane elastomer (1185A, Shore A hardness 90A), 0.5g antioxidant 1010; modified nonwoven fabric substrate (100cm²). 2 Dosage: 8g Composite antibacterial self-adhesive layer: silicone pressure-sensitive adhesive (Wacker SILPURAN® 2114) 25g, rosin-based tackifying resin (Foral 85) 5g, polyethylene glycol softener (polyethylene glycol 400) 2g; Anti-stick layer: 1 sheet of fluorosilicone release film; The preparation steps are as follows: Same as in Example 1, except that: S1: Modified nonwoven fabric substrate: 100cm 2 Nonwoven fabric, dried at 80℃ for 15 min with 60 mL of 5 wt% carboxymethyl chitosan aqueous solution, moisture content 3.9%, loading 1.5 mg / cm³. 2 ; S2: Support layer slurry: 20g biaxial polymer + 5g carboxymethyl chitosan-silver nanocomposite microparticles + 12g polyurethane elastomer (1185A, Shore hardness 90A) + 0.5g antioxidant 1010. After twin-screw mixing, 25g of particles are dissolved in 58.3g dichloromethane (solid content 30%). S3: Composite support layer: Coating thickness 0.4mm, dried at 80℃ for 10min, thickness after drying 0.2mm; S4: Self-adhesive layer paste: 25g silicone pressure-sensitive adhesive (Wacker SILPURAN® 2114) + 5g rosin-based tackifying resin (Foral 85) + 2g polyethylene glycol softener (polyethylene glycol 400), stir at 50℃ for 20min (add stirring once during the process to avoid sedimentation); S5: Composite anti-stick layer: self-adhesive coating thickness 0.25mm, 0.15MPa lamination for 3min; S6: Cutting: Finished product 12cm×180cm, accuracy ±0.05cm; This embodiment uses the upper limit formulation of self-adhesive layer raw materials, increases the amount of silicone pressure-sensitive adhesive and tackifying resin, improves peel strength to 2.0N / 25mm, and due to the increase in polyethylene glycol (2g), the self-adhesive layer has better flexibility and no tightness when fitting the knee joint; the upper limit of the support layer raw material (20g biaxial polymer + 12g polyurethane) makes the elastic recovery rate reach 97.1% and the elongation at break 350%, resulting in better dynamic support effect.

[0026] Test Project Test Results Elastic recovery rate 97.1% Elongation at break 350% Antibacterial rate (E. coli) 99.5% Peel strength 2.0N / 25mm Release force 8.2g / 25mm Example 4: Please see Figure 1 The present invention provides a technical solution: a self-adhesive bandage for the knee joint and a method for preparing the same, comprising the following raw material formula: Support layer: 18g biaxial polymer, 4g carboxymethyl chitosan-silver nanoparticles, 10g polyurethane elastomer (1185A, Shore A hardness 80A), 0.4g antioxidant 1010; modified nonwoven fabric substrate (100cm²). 2 Dosage: 6g Composite antibacterial self-adhesive layer: silicone pressure-sensitive adhesive (Dow Corning MG 7-9850) 22g, rosin-based tackifying resin 4g (Foral85), polyethylene glycol softener (polyethylene glycol 400) 1.5g; Anti-stick layer: One sheet (100cm) of fluorosilicone release film (15g fluorosilicone polymer, 30g toluene, 1g crosslinking agent, 0.3g catalyst). 2 ); The preparation steps are as follows: S1-S4: Same as in Example 1; Preparation of the anti-stick layer: 15g fluorosilicone polymer + 30g toluene + 1g crosslinking agent (triethoxysilane) + 0.3g catalyst (dibutyltin dilaurate), stir for 30min; coating thickness 1μm, cure at 150℃ for 10min; S5: Composite anti-adhesive layer: self-adhesive layer coating thickness 0.2mm, after covering with anti-adhesive layer, composite at 0.15MPa for 3min; S6: Cut to a finished product of 10cm x 150cm; This embodiment focuses on the upper limit formulation of the release layer raw materials. The increased amount of fluorosilicone polymer and crosslinking agent improves the temperature resistance of the release film (no deformation after curing at 150℃). After 6 months of storage, the release force changes by only 3.1%, which is far lower than the industry standard of 5%, making it suitable for long-term storage.

[0027] Test Project Test Results Elastic recovery rate 96.8% Antibacterial rate 99.3% Peel strength 1.7N / 25mm Release force 9.8g / 25mm Storage stability (6 months) Stored in a 60℃ oven, release force changes were measured. Comparative Example 1: Please see Figure 1 The present invention provides a comparative scheme, including a raw material formula: Support layer: 18g biaxial polymer, 10g polyurethane elastomer, 0.4g antioxidant 1010 (removing 4g carboxymethyl chitosan-silver nanoparticles); the rest is the same as in Example 1; The preparation steps are as follows: same as in Example 1; The comparative example lacked the core antibacterial component (carboxymethyl chitosan-silver nanoparticles), and the antibacterial rate decreased from 99.2% to 12.5%, only slightly higher than the blank control group. This proves that the composite particles are the key to achieving long-lasting antibacterial effect, highlighting the necessity of the antibacterial component in the technical solution of this invention.

[0028] Test Project Test Results Difference analysis with Example 1 Antibacterial rate (E. coli) 12.5% Without nano-silver antibacterial properties, the antibacterial rate drops sharply. Skin irritation No redness or swelling Indifference Elastic recovery rate 97.0% The absence of composite microparticles does not affect elasticity. Comparative Example 2: Please see Figure 1 The present invention provides a comparative scheme, including a raw material formula: Self-adhesive layer: 22g of ordinary acrylic pressure-sensitive adhesive (replacing silicone pressure-sensitive adhesive (Wacker SILPURAN® 2114)), 4g of rosin-based tackifying resin (Foral 85), 1.5g of polyethylene glycol softener (polyethylene glycol 400); the rest is the same as in Example 1; The preparation steps are as follows: same as in Example 1; This comparative example uses ordinary acrylic pressure-sensitive adhesive instead of silicone pressure-sensitive adhesive. Although the peel strength is increased, there are three major problems: first, the adhesion is too strong, resulting in adhesive residue on the skin; second, the sensitization is high, which does not meet medical standards; and third, the sweat resistance is poor, which cannot be adapted to the scenario of sweating knee joints. This proves that the low sensitization and sweat resistance of silicone pressure-sensitive adhesive are the core of the self-adhesive layer of this invention and cannot be replaced.

[0029] Test Project Test Results Difference analysis with Example 1 Peel strength 2.5N / 25mm If the adhesive is too strong, it will easily leave glue residue. Skin irritation 30% of volunteers experienced mild redness and swelling. Acrylic pressure-sensitive adhesives have high sensitizing properties. Sweat resistance (immersion in sweat for 2 hours) The peel strength decreased to 0.8 N / 25 mm. Viscosity decreased by 61%, rendering it unusable. Comparative Example 3: Please see Figure 1 The present invention provides a comparative scheme, including a raw material formula: Anti-stick layer: 1 sheet of ordinary polyethylene release film (25μm thick) (replacing fluorosilicone release film); the rest is the same as in Example 1; The preparation steps are as follows: same as in Example 1; In this comparative example, ordinary polyethylene release film was used instead of fluorosilicone release film. The release force was too high (35g / 25mm), requiring the use of tools such as scissors to peel it off. After one month of storage, the release force increased sharply due to adhesive migration, and the self-adhesive layer's adhesiveness decreased, rendering it unusable. This demonstrates that the low release force and high stability of the fluorosilicone release film are key to protecting the self-adhesive layer's function, which meets the design requirements of the anti-adhesive layer in this invention.

[0030] Test Project Test Results Difference analysis with Example 1 Release force 35g / 25mm Excessive release force necessitates tool peeling. Storage stability (1 month) Release force increased to 50g / 25mm Viscous migration, release force increases sharply Self-adhesive layer adhesive The peel strength decreased to 1.2 N / 25 mm. Release film residue, adhesion reduced by 33%. Examples 1-4, based on the technical solutions in the claims, comprehensively demonstrate the feasibility and superiority of the technical solutions by covering the range of raw material usage, verifying the synergistic effect of components and process adaptability. Comparative Examples 1-3, by omitting key components or replacing core materials, reversely confirm the inventiveness and irreplaceability of the key technical features of the solutions, forming a significant breakthrough over the prior art as a whole. Example 1 serves as the baseline scheme, employing the intermediate raw material ratios of the claims (support layer: 18 parts biaxial polymer, 4 parts carboxymethyl chitosan-silver nanoparticles, 10 parts polyurethane elastomer, 0.4 parts antioxidant; composite antibacterial self-adhesive layer: 22 parts silicone pressure-sensitive adhesive, 4 parts rosin-based tackifying resin, 1.5 parts polyethylene glycol softener; anti-adhesive layer: 12 parts fluorosilicone polymer, 25 parts toluene, 0.8 parts crosslinking agent, 0.2 parts catalyst), combined with standard processes (preparation of modified nonwoven fabric substrate in an environment with humidity ≤60%, melt blending in a twin-screw extruder at 300 r / min, and composite of the self-adhesive layer and anti-adhesive layer in an environment with humidity ≤50%), achieving the synergistic effect of each layer's components—the biaxial polymer (crystalline crosslinked polyurethane and SBS elastomer interpenetrating network structure) in the support layer imparts dynamic properties to the bandage. The bandage exhibits excellent adaptability, autonomously adjusting its shape to maintain support as the knee flexes and extends. Carboxymethyl chitosan-silver nanoparticles, leveraging the antibacterial properties of silver nanoparticles and the biocompatibility of carboxymethyl chitosan, construct a long-lasting antibacterial barrier. Polyurethane elastomers further enhance the elastic recovery of the support layer. The composite antibacterial self-adhesive layer features silicone pressure-sensitive adhesive with both low allergenicity and stable adhesion, while rosin-based tackifying resin optimizes adhesion durability. Polyethylene glycol softener improves the flexibility of the adhesive layer, preventing skin discomfort during wear. The fluorosilicone release film in the anti-adhesive layer, through the reaction of fluorosilicone polymers with crosslinking agents and catalysts, forms a release effect compatible with the self-adhesive layer, ensuring easy peeling without adhesive residue. These layers work synergistically to give the bandage high elasticity, stable self-adhesion, antibacterial safety, and comfortable fit, perfectly meeting the dynamic care needs of the knee joint.Example 2 focuses on verifying the highly elastic boundary of the support layer, using 20 parts of bidirectional polymer (upper limit) and 12 parts of polyurethane elastomer. This ratio allows the interpenetrating network structure of the bidirectional polymer and the polyurethane elastomer to form a stronger elastic synergy, enabling the bandage to maintain stable support and elastic recovery during repeated knee flexion and extension, avoiding the problems of looseness or tightness in traditional bandages. Simultaneously, 3 parts of carboxymethyl chitosan-silver nanoparticles (lower limit) still maintain the basic antibacterial effect, demonstrating the flexibility of adjusting the amount of support layer raw materials. Example 3 focuses on optimizing antibacterial performance, increasing the carboxymethyl chitosan-silver nanoparticles to 5 parts (upper limit). The synergistic effect of nano-silver and carboxymethyl chitosan in the composite particles is significantly enhanced, forming denser antibacterial sites on the bandage surface. Furthermore, the presence of carboxymethyl chitosan prevents nano-silver agglomeration, ensuring a uniform and long-lasting antibacterial effect. Combined with 15 parts of bidirectional polymer (lower limit) and 8 parts of polyurethane elastomer, good performance is still maintained. The elasticity and support meet the high antibacterial requirements of scenarios such as postoperative recovery. Example 4 verifies the compatibility between the self-adhesive layer and the release layer. A self-adhesive layer formulation of 25 parts (upper limit) of silicone pressure-sensitive adhesive, 5 parts of rosin-based tackifying resin, and 2 parts of polyethylene glycol softener is used, along with a release layer formulation of 15 parts (upper limit) of fluorosilicone polymer. The high adhesion of the silicone pressure-sensitive adhesive is further enhanced by the rosin-based tackifying resin, and the polyethylene glycol softener prevents the adhesive layer from becoming too hard. The fluorosilicone release film ensures compatibility and peeling with the high-adhesion self-adhesive layer through a higher content of fluorosilicone polymer. This verifies the process compatibility of the upper limit of the raw material dosage for the self-adhesive layer and the release layer. In addition, all examples strictly follow the process parameters in the example (such as drying the modified non-woven fabric substrate to a moisture content of ≤5%, coating thickness of the support layer slurry of 0.3-0.4 mm, coating thickness of the self-adhesive layer of 0.15-0.25 mm, and composite pressure of 0.15 MPa, etc.) to ensure stable product performance and prevent quality problems caused by process fluctuations. Comparative Example 1, lacking the bidirectional polymer and replaced with 18 parts of ordinary polyurethane resin, suffers from the inability of ordinary polyurethane to adjust its shape with knee flexion and extension due to its lack of shape memory and interpenetrating network structure. This results in displacement or localized pressure after wearing, significantly reduced elastic recovery, and an inability to provide continuous and stable support, highlighting the decisive role of the bidirectional polymer in the dynamic adaptability of the bandage. Comparative Example 2, by removing carboxymethyl chitosan-silver nanoparticles, retains only the bidirectional polymer, polyurethane elastomer, and antioxidants in the support layer. This results in the bandage losing its antibacterial barrier, leading to a failure in simulated knee... Bacteria easily grow in the closed and humid environment of joints, posing a risk of infection. This proves that carboxymethyl chitosan-silver nanoparticles are the core of achieving antibacterial function. In Comparative Example 3, 22 parts of natural rubber pressure-sensitive adhesive were used to replace silicone pressure-sensitive adhesive. Natural rubber pressure-sensitive adhesive not only showed large fluctuations in adhesion with temperature (easy to delaminate at low temperatures and easy to leave residues at high temperatures), but also caused skin allergic reactions in some samples. At the same time, it had poor compatibility with rosin-based tackifying resin and polyethylene glycol softener, and the adhesive layer was prone to cracking. This verified the irreplaceable nature of silicone pressure-sensitive adhesive in terms of low allergenicity, adhesion stability and component compatibility.Comparative Examples 1-3 demonstrate the value of key components by highlighting their performance shortcomings. This solution relies on the synergistic design of bidirectional polymers, carboxymethyl chitosan-silver nanoparticles, silicone pressure-sensitive adhesive, and fluorosilicone release film to solve problems such as the imbalance between elasticity and stability, defects in self-adhesive properties, insufficient antibacterial protection, and poor skin compatibility of traditional knee bandages. It achieves a synergistic effect of high elastic support, stable self-adhesion, long-lasting antibacterial effect, and comfortable and low-allergenic properties, which better meets the dual requirements of functionality and safety for medical care products compared to existing technologies.

[0031] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific technical solutions or characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A knee joint self-adhesive bandage characterized by comprising: The support layer, the composite antibacterial self-adhesive layer and the anti-adhesive layer are sequentially arranged from bottom to top. The support layer is prepared from the following raw materials in parts by weight: bidirectional polymer 15-20 parts, carboxymethyl chitosan-nano silver composite particles 3-5 parts, polyurethane elastomer 8-12 parts, antioxidant 0.3-0.5 parts. The composite antibacterial self-adhesive layer is prepared from the following raw materials in parts by weight: silicone pressure-sensitive adhesive 20-25 parts, rosin-based tackifying resin 3-5 parts, polyethylene glycol softener 1-2 parts. The anti-adhesive layer is a fluorosilicon release film prepared from the following raw materials in parts by weight: fluorosilicon polymer 10-15 parts, toluene 20-30 parts, 0.5-1 part crosslinking agent, 0.1-0.3 part catalyst. The amount of fluorosilicon release film is 1-2 pieces matching the area of the composite antibacterial self-adhesive layer.

2. The self-adhering high elasticity bandage for knee according to claim 1, wherein The preparation method of the fluorosilicon release film comprises: dissolving fluorosilicon polymer 10-15 parts in toluene 20-30 parts, adding 0.5-1 part crosslinking agent and 0.1-0.3 part catalyst, uniformly stirring, coating on a polyester film, coating thickness 0.5-1 μm, curing at 120-150 ℃ for 10-15 minutes to form a release film.

3. The self-adhering high elasticity bandage for knee according to claim 1, wherein The bidirectional polymer is an interpenetrating network structure formed by crystalline crosslinked polyurethane and SBS elastomer, and its preparation method comprises: mixing polyurethane prepolymer and SBS elastomer at a mass ratio of 3:1, adding dibutyltin dilaurate catalyst (amount is 0.5% of the total mass) at 60 ℃, and preparing by two-step crosslinking reaction; the polyurethane prepolymer is toluene diisocyanate (TDI) type polyurethane prepolymer or diphenylmethane diisocyanate (MDI) type polyurethane prepolymer.

4. The self-adhering high elasticity bandage for knee according to claim 1, wherein The preparation method of the carboxymethyl chitosan-nano silver composite particles comprises: dissolving 3-7 g of carboxymethyl chitosan in 80-120 mL of 2 wt% acetic acid solution, adding 0.8-1.2 mL of 0.1 mol / L silver nitrate solution, stirring at 25-35 ℃ for 25-35 minutes, then adding 8-12 mL of 0.05 mol / L vanillin ethanol solution dropwise, continuing to react for 2.5-3.5 hours, and freeze-drying to obtain composite particles with an average particle size of 40-50 nm.

5. The self-adhering high elasticity bandage for knee according to claim 1, wherein The support layer further comprises a non-woven fabric substrate modified by carboxymethyl chitosan, and the modification method is: soaking the non-woven fabric in a 5 wt% carboxymethyl chitosan aqueous solution for 30 minutes, and then drying at 80 ℃ to form an antibacterial enhancement layer; the polyurethane elastomer is a polyether type thermoplastic polyurethane elastomer (TPU).

6. A method of producing the self-adhesive high-elasticity bandage for the knee joint as claimed in any one of claims 1 to 5, characterized by, The method comprises the following steps: S1: Preparation of modified non-woven fabric substrate: non-woven fabric was soaked in 5wt% carboxymethyl chitosan aqueous solution for 30 minutes, and dried at 80°C to a water content of ≤5%, to obtain a modified non-woven fabric substrate with a carboxymethyl chitosan loading of 1.2-1.5mg / cm 2 ; S2: preparing a support layer slurry: taking 15-20 parts of bidirectional polymer, 3-5 parts of carboxymethyl chitosan-nano silver composite particles, 8-12 parts of polyurethane elastomer, and 0.3-0.5 parts of antioxidant in parts, adding them into a twin-screw extruder, melt blending at 120 ℃ for 15 minutes, extruding and granulating, and then dissolving in dichloromethane to prepare a slurry with a solid content of 30%; S3: composite support layer: coating the slurry obtained in S2 on the surface of the modified non-woven fabric substrate prepared in S1 (coating thickness 0.3-0.4 mm), drying at 80 ℃ for 10 minutes to form a support layer; S4: Preparation of composite antibacterial self-adhesive layer paste: 20-25 parts of silicone pressure-sensitive adhesive, 3-5 parts of rosin-based tackifying resin, and 1-2 parts of polyethylene glycol softener were weighed out and added to a planetary mixer, which was stirred at 200 r / min for 20 minutes at 50°C; S5: Composite self-adhesive layer and release layer: the paste obtained in S4 was coated on the surface of the support layer (coating thickness 0.15-0.25 mm), and after standing at room temperature for 5 minutes, a fluorosilicon release film was overlaid, and a pressure of 0.15 MPa was applied for 3 minutes; S6: Cutting and forming: the composite bandage was cut into finished products with a width of 7-12 cm and a length of 120-180 cm using a laser cutting machine, and the cutting accuracy was controlled to be ±0.05 cm.

7. The method for preparing a self-adhesive high-elasticity bandage for the knee joint according to claim 6, characterized in that, The preparation of the modified non-woven fabric substrate in S1 was carried out in a clean environment with a humidity of ≤60%.

8. The method for preparing a self-adhesive high-elasticity bandage for the knee joint according to claim 6, characterized in that, The composite process in S5 was carried out in a clean room environment with a humidity of ≤50%.

9. The method for preparing a self-adhesive high-elasticity bandage for the knee joint according to claim 6, characterized in that, The screw rotation speed of the twin-screw extruder in S2 was 300 r / min.

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