A PCM constant-temperature cold compress and gradient pressure integrated detumescence bandage and a preparation method thereof

Abstract

This invention provides an integrated PCM constant-temperature cooling and gradient pressure anti-swelling bandage and its preparation method. It comprises: a skin contact layer, a PCM constant-temperature hydrogel cooling layer, a gradient elastic pressure layer, and a breathable and waterproof backing layer. The invention verifies through DSC experiments that the C14 / C16 eutectic mixture exhibits a single endothermic peak within a ratio range of 5:95 to 32:68 (excluding approximately 8%-12% critical transition zone), with a measured phase transition enthalpy of 163.79-210.48 J / g and a phase transition peak temperature covering 10.03-18.48°C. The gradient elastic pressure layer decreases from 25-30 mmHg at the distal end to 15-20 mmHg at the proximal end, promoting the return of edema fluid; the TPU temperature-sensitive coating enhances elastic recoil force at low temperatures, achieving a synergistic effect of cooling and pressure.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to a PCM constant temperature cold compress and gradient pressure integrated swelling reduction bandage and its preparation method. Background Technology

[0002] Cold compress therapy is a common clinical method for physical cooling and reducing swelling after acute soft tissue injuries (such as fractures, sprains, contusions, etc.). Its basic principle is to reduce local tissue temperature, promote vasoconstriction, reduce the release of pain-inducing substances, and lower the tissue metabolic rate, thereby reducing swelling and relieving pain. Currently, products used clinically for cold compresses to reduce swelling after trauma mainly include the following categories: (1) Ice packs and traditional cold compresses; Ice packs or gel cooling patches achieve cooling by absorbing heat through the solid-liquid phase change of ice / gel, and are the most traditional method of cold compress in clinical practice. However, these products have significant drawbacks: the temperature of ice packs is uncontrollable, and the temperature is too low when taken directly from the refrigerator, which can easily cause frostbite if it comes into direct contact with the skin; the cooling effect is short-lived, usually lasting less than 1 hour; and the ice pack itself has no fixed structure, requiring the use of additional bandages or towels for fixation, which is cumbersome and results in poor patient compliance.

[0003] (2) Alcohol-containing cold compress bandages (such as "Bone Plus" type products); These products primarily contain menthol, ethanol, glycerin, and water, relying on the evaporation of the liquid to remove heat and achieve a cooling effect. However, their cooling effect typically lasts only 1-2 hours before becoming ineffective; the alcohol content (usually >20%) can easily cause adverse reactions such as itchy skin and allergies; and they lack elastic pressure-bearing properties, failing to promote the drainage of edema fluid.

[0004] (3) Phase change material (PCM) cold compress products; In recent years, phase change materials (PCMs) have attracted widespread attention in the fields of wearable thermal management and medical cooling due to their advantages such as high energy density, controllable phase change temperature, and strong cycle stability. Existing literature reports the application of PCMs in medical dressings and bandages, utilizing the property of PCMs to absorb a large amount of latent heat and maintain a nearly constant temperature during solid-liquid phase change to achieve continuous constant-temperature cooling.

[0005] Existing PCM cold compress products use flexible, cold-storing phase change materials that remain soft before and after cold storage, allowing them to conform to joint areas and are equipped with elastic bandages. However, these products still have the following shortcomings: ① They need to be frozen in a -18°C to -20°C freezer for 2 hours before use, limiting their application scenarios and preventing them from being used immediately after opening; ② They only provide a cold compress function and are not organically integrated with the elastic compression function, while the combined application of cold compress and compression has been proven to significantly accelerate swelling reduction; ③ Most existing PCM cold compress products use fatty acid ester PCM (such as CN114305852A), whose latent heat of phase change is 160-190 J / g, and their biocompatibility is not as good as that of alkane PCM (fatty acid esters have the risk of hydrolysis); ④ PCM is mostly stored in simple packaging or gel tanks, without microencapsulation technology, posing a risk of leakage.

[0006] (4) Elastic compression bandage; Ordinary elastic bandages or gradient pressure bandages promote the return of edema fluid along the lymphatic / venous system by applying physical pressure. However, they only provide pressure and do not provide cold compress, requiring the use of ice packs separately. Using ice packs and elastic bandages separately is not only cumbersome but also makes it difficult to ensure precise alignment of the cold compress and pressure surfaces, affecting clinical outcomes.

[0007] (5) Active circulating cold compress system; Products like Game Ready and Aircast Cryo / Cuff utilize a water pump to drive ice water circulation combined with intermittent air pressure boosting, demonstrating significant clinical efficacy. However, these products require an external power source, are not portable, are unsuitable for everyday home use, and cost several thousand yuan per unit, making them expensive and difficult to popularize.

[0008] (6) Passive cold compress bandages (such as IceBand Medical products); It uses a freezing water element in conjunction with an insulation layer to maintain a temperature of ≥10°C. The passive cooling time is about 45-60 minutes, and it needs to be repeatedly frozen in a household refrigerator to maintain the effect. It does not have the ability to maintain a constant temperature for ≥8 hours with PCM, and it does not have an elastic pressure function.

[0009] (7) The sealing and skin contact issues of existing PCM cold compress bandages; Existing PCM cold compress bandages also have shortcomings in their skin contact layer design: some products use the vaporization of water in the polymer gel to remove heat, resulting in a limited duration of cold compress; some products contain irritating ingredients such as alcohol; and the skin contact layer lacks antibacterial and sensitization-reducing functional designs. Furthermore, existing PCM bandages often use simple physical encapsulation for the PCM layer, lacking effective leakage prevention measures.

[0010] In summary, existing cold compress products have failed to simultaneously address the following key technical issues: ① The duration of constant temperature cold compress is short, failing to meet the clinical need for continuous cold compresses of ≥8 hours; ② The cold compress and pressure functions are separate, requiring the use of different products, which is cumbersome; ③ There is a lack of a synergistic enhancement mechanism between cold compress and pressure; ④ The selection of PCM phase change materials still has shortcomings in terms of the accuracy of phase change temperature, latent heat of phase change, and biosafety; ⑤ Pre-treatment by freezing is required before use, making it impossible to achieve room temperature storage and ready-to-use upon opening. Summary of the Invention

[0011] This invention designs an integrated PCM constant temperature cold compress and gradient pressure swelling reduction bandage and its preparation method. The technical problems it solves are: the short duration of constant temperature in existing cold compress products, uncontrollable temperature, separation of cold compress and pressure functions, leakage risk of PCM phase change material and the need for freezing pretreatment before use, and the extremely short cooling time of existing cold compress sprays.

[0012] To solve the aforementioned technical problems, the present invention adopts the following solution: A PCM constant temperature cooling and gradient pressure integrated anti-swelling bandage comprises, from the inside out: a skin contact layer, which is a non-woven fabric blended with bamboo fiber and cotton, treated with chitosan solution; a PCM constant temperature hydrogel cooling layer, which is a phase change material composed of a polyacrylate gel matrix with a composite tetradecane and hexadecane eutectic mixture as the phase change material, and the phase change temperature is 10-18.5°C; a gradient elastic pressure layer, which is an elastic webbing blended with spandex and polyester, with its inner surface coated with a TPU temperature-sensitive coating, the pressure at the distal end being 25-30 mmHg, decreasing to 15-20 mmHg towards the proximal end; and a breathable and waterproof backing layer.

[0013] Preferably, in the PCM constant temperature hydrogel cooling layer, the total PCM content is 8-12wt%, the water content is 72-78wt%, and the constant temperature time is ≥8 hours.

[0014] Preferably, the areal density of the skin contact layer is 50-80 g / m². 2 The chitosan solution concentration is 1.0-2.0 wt%, the ethanol content is ≤5 wt%, and the pH value is 5.5-6.5.

[0015] Preferably, in the tetradecane and hexadecane eutectic mixture, the mass percentage of tetradecane is 5-35% and the mass percentage of hexadecane is 65-95%.

[0016] Preferably, in the tetradecane and hexadecane eutectic mixture, the mass percentage of tetradecane is 5-32%, but excluding 8%-12%; the mass percentage of hexadecane is 68-95%; the DSC temperature rise curve of the tetradecane and hexadecane eutectic mixture shows a single endothermic peak with a peak temperature of 10°C-18.5°C.

[0017] Preferably, the coating amount of the TPU temperature-sensitive coating is 5-10 g / m². 2 The TPU temperature-sensitive coating enhances elasticity and resilience in environments below 25°C; the outer surface of the breathable and waterproof backing layer is provided with a natural latex self-adhesive layer, which contains no chemical tackifiers.

[0018] Preferably, the breathable and waterproof backing layer is composed of a polyurethane breathable film and a polyester nonwoven fabric, wherein the thickness of the polyurethane breathable film is 0.05-0.08 mm and the moisture permeability is ≥3000 g / m³. 2 / 24h.

[0019] Preferably, the PCM constant temperature hydrogel cooling layer further includes 1.5-2.5 wt% C20-C24 paraffin, and 0.3-0.5 wt% menthol and / or 0.2-0.3 wt% borneol.

[0020] Preferably, the tetradecane and hexadecane eutectic mixture in the PCM constant temperature hydrogel cooling layer is encapsulated using a microencapsulation process, with the wall material being melamine resin or silica, and the microcapsule particle size being 50-200μm.

[0021] A method for preparing the above-mentioned PCM constant temperature cold compress and gradient pressure integrated swelling reduction bandage includes the following steps: Step 1, Prepare the PCM hydrogel cooling layer: Mix deionized water, glycerin, and sodium polyacrylate until uniformly swollen; add a mixture of tetradecane and hexadecane eutectic and stir at low speed until uniform; add additives, stir, and then pour into a mold with a thickness of 3-4 mm, and let it solidify. Step 2, Preparation of the skin contact layer: Bamboo fiber and cotton blended nonwoven fabric is impregnated in chitosan finishing solution and dried; Step 3, prepare the gradient elastic pressure layer: coat the inner surface of the spandex and polyester blended elastic webbing with a TPU temperature-sensitive coating, and dry and cure it; Step 4, prepare the breathable and waterproof backing layer: heat-press the polyurethane breathable film with polyester nonwoven fabric. Step 5: Apply heat-pressed composite layers in the following order: skin contact layer, PCM constant temperature hydrogel cooling layer, gradient elastic pressure layer, and breathable waterproof backing layer. Step six: Cut the packaging.

[0022] Preferably, in step one, based on 1000 g of total mixture, deionized water is 720-780 g, glycerin is 50-80 g, sodium polyacrylate is 80-100 g, and a tetradecane and hexadecane eutectic mixture is 80-120 g, wherein the mass percentage of tetradecane is 5-32%, but excluding 8%-12%; the auxiliary agents include 15-25 g of C20-C24 paraffin, 3-5 g of menthol, 2-3 g of borneol, 1-2 g of methylparaben, and brilliant blue pigment.

[0023] Preferably, in step two, the chitosan concentration in the chitosan finishing solution is 1.0-2.0 wt%, the chitosan is dissolved in a 1% acetic acid aqueous solution, and 3.0-5.0 wt% glycerol is added as a softening agent; the padding residue is 80%, and the drying temperature is 80°C.

[0024] Preferably, in step three, the coating amount of the TPU temperature-sensitive coating (5) is 5-10 g / m². 2 In step four, a natural latex self-adhesive layer is coated on the outer surface of the breathable and waterproof backing layer, wherein no chemical tackifier is added to the natural latex self-adhesive layer.

[0025] Preferably, in step five, the temperature of hot pressing is 80-120°C, the pressure is 0.3-0.5 MPa, and the time is 10-30 seconds.

[0026] Preferably, in step one, the tetradecane and hexadecane eutectic mixture is pre-microencapsulated before being added.

[0027] A PCM constant-temperature cooling spray includes: an aerosol can; an atomizing nozzle disposed on the aerosol can; and a spray matrix filled within the aerosol can; the spray matrix contains PCM microcapsules, the core material of which is a eutectic mixture of tetradecane and hexadecane, wherein the mass percentage of tetradecane in the eutectic mixture is 5-32%, excluding 8%-12%; and the mass percentage of hexadecane is 68-95%. The DSC temperature rise curve of the core material shows a single endothermic peak with a peak temperature of 10-18.5°C; the PCM microcapsules are dispersed in the spray matrix; the spray matrix contains a thickening suspending agent, a film-forming agent, a moisturizer, and a propellant; the PCM microcapsules adhere to the skin surface after spraying, providing continuous constant-temperature cooling through phase change endothermic absorption.

[0028] Preferably, in the core material of the PCM microcapsules, the mass ratio of tetradecane to hexadecane is 5:95 to 32:68, and the phase transition temperature is 11-18°C; the wall material of the PCM microcapsules is melamine resin or silica, and the particle size is 10-50 μm; the content of PCM microcapsules in the spray matrix is ​​8-12 wt%.

[0029] Preferably, the film-forming agent is chitosan, and the content of chitosan in the spray matrix is ​​0.5-1.0 wt%; the thickening and suspending agent is carbomer 940, and the content of carbomer 940 in the spray matrix is ​​0.3-0.5 wt%; the propellant is pure nitrogen gas at a pressure of 0.3-0.5 MPa.

[0030] Preferably, the spray matrix further includes 0.3-0.5 wt% menthol and / or 0.2-0.3 wt% borneol; the pH value of the spray matrix is ​​5.5-6.5.

[0031] A PCM constant temperature cold compress combination kit is characterized by comprising the aforementioned PCM constant temperature cold compress and gradient pressure integrated anti-swelling bandage, as well as the aforementioned PCM constant temperature cold compress spray; in use, the spray is first sprayed onto the affected area for rapid cold compress, and then the bandage is wrapped around the affected area for continuous cold compress and pressure.

[0032] Application of a PCM constant temperature cold compress and gradient pressure integrated swelling reduction bandage in the preparation of medical devices for physical cooling and swelling reduction after acute soft tissue injury.

[0033] The PCM constant temperature cold compress and gradient pressure integrated swelling reduction bandage and its preparation method have the following beneficial effects: (1) Through systematic DSC experiments, this invention has determined the preferred ratio range of C14 / C16 eutectic mixtures with a C14 mass percentage of 5%-32% (excluding the critical transition region of approximately 8%-12%). Within this range (excluding the critical transition region of approximately 8%-12% C14), the DSC temperature rise curve of the eutectic mixture exhibits a single endothermic peak, and the phase transition peak temperature Tpm covers 10.03°C to 18.48°C. Different ratios can be selected to adjust the cold compress temperature according to clinical needs. The measured phase transition enthalpy ΔHm across the entire range was 163.79-210.48 J / g. Among these, formulations with C14 content ≤28% (such as PCM-F, PCM-H, PCM-I, PCM-A, PCM-B, and PCM-C) exhibited phase transition enthalpies ≥170 J / g, reaching a maximum of 210.48 J / g (PCM-F, 5:95), which is superior to the 160-190 J / g of existing fatty acid ester PCMs. However, the phase transition enthalpy of PCM-D (32:68) was 163.79 J / g, still higher than the lower limit for fatty acid esters. DSC data from the nine samples verified the monotonic correlation between formulation ratio and phase transition temperature, providing an experimental basis for precise control of the cold compress temperature.

[0034] The measured phase transition peak temperature Tpm ranges from 10.03°C to 18.48°C, which is consistent with the upper limit of 10-18.5°C for phase transition temperature in this invention.

[0035] (2) This invention integrates the PCM constant temperature hydrogel cooling layer with the gradient elastic pressure layer. The gradient pressure design of 25-30 mmHg at the distal end, 20-25 mmHg in the middle, and 15-20 mmHg at the proximal end can promote the return of edema fluid along the lymphatic / venous system to the proximal end. The integrated cooling and pressure functions avoid the cumbersome operation of using ice packs and elastic bandages separately in traditional solutions.

[0036] (3) The present invention coats the inner surface of the elastic pressure layer with a TPU temperature-sensitive coating. The TPU material has enhanced elastic recoil force in environments below 25°C. When the PCM hydrogel cooling layer releases cold energy, the TPU temperature-sensitive coating automatically tightens. The longer the cooling duration, the more obvious the shrinkage of the TPU temperature-sensitive coating, and the stronger the automatic pressure effect, thus realizing the automatic synergistic enhancement of cooling and pressure.

[0037] (4) The skin contact layer of the present invention is treated with chitosan solution. The cationic properties of chitosan endow it with antibacterial properties. Chitosan has good biocompatibility and can promote wound healing. The chitosan-treated layer serves as a buffer interface between the skin and the PCM hydrogel layer. Combined with a low-alcohol formula (ethanol content ≤ 5 wt%), it can reduce the risk of skin sensitization.

[0038] (5) The present invention also provides a PCM constant temperature cooling spray containing C14 / C16 eutectic PCM microcapsules. After spraying, the microcapsules adhere to the skin surface and provide continuous constant temperature cooling through phase change heat absorption. The spray can be used alone on areas where it is inconvenient to wrap bandages, or it can be used in combination with bandages to achieve both immediate and continuous cooling effects.

[0039] (6) The product of the present invention utilizes the property that the PCM eutectic mixture undergoes a solid-liquid phase change at 10-18.5°C, requiring no refrigeration or freezing pretreatment, and is ready to use upon opening, making it convenient to use. Attached Figure Description

[0040] Figure 1 : A schematic diagram of the four-layer structure of the PCM constant temperature cold compress and gradient pressure integrated swelling reduction bandage described in this invention; Figure 2 : A schematic diagram of the phase transition temperature-time curve of the C14 / C16 eutectic PCM mixture described in this invention; Figure 3 : A schematic diagram of the gradient pressure distribution of the bandage described in this invention; Figure 4 : A schematic diagram illustrating the usage state of the PCM constant temperature cold compress spray described in this invention; Figure 5 : Overlay of DSC heating curves of the C14 / C16 eutectic PCM mixture under different ratios as described in this invention; Figure 6: DSC temperature rise curve of the PCM-F (C14:C16=5:95) sample described in this invention; Figure 7 : DSC temperature rise curve of the PCM-A (C14:C16=20:80) sample described in this invention; Figure 8 The DSC temperature rise curve of the PCM-E (C14:C16=38:62) sample described in this invention (showing a double peak).

[0041] Explanation of reference numerals in the attached figures: 1—Skin contact layer; 2—PCM constant temperature hydrogel cooling layer; 3—Gradient elastic pressure layer; 4—Breathable and waterproof backing layer; 5—TPU temperature-sensitive coating; 6—Natural latex self-adhesive layer; 7—Aerosol can; 8—Atomizing nozzle; 9—PCM microcapsule attachment layer; 10—Chitosan film-forming protective layer. Detailed Implementation

[0042] The following is combined with Figures 1 to 8 The present invention will be further described as follows: like Figure 1 As shown, the PCM constant temperature cold compress and gradient pressure integrated swelling reduction bandage of the present invention includes, from the inside (skin contact surface) to the outside: Skin contact layer 1 is a non-woven fabric blended with bamboo fiber and cotton, with a surface density of 50-80 g / m². 2 The material is treated with a 1.0-2.0 wt% chitosan solution, with an ethanol content ≤5 wt% and a pH value ≈6.0. The chitosan-treated layer has antibacterial properties, promotes wound healing, and reduces the risk of skin sensitization.

[0043] PCM constant temperature hydrogel cooling layer 2 is a composite tetradecane C14 and hexadecane C16 eutectic mixture as PCM in a sodium polyacrylate gel matrix, with a phase transition temperature of 10-18.5°C, a total PCM content of 8-12 wt%, a water content of 72-78 wt%, and a continuous constant temperature time of ≥8 hours. This layer is the core function of the product, providing a constant low-temperature cooling effect.

[0044] The gradient elastic pressure layer 3 is made of spandex and polyester blended elastic webbing, and its inner surface is coated with TPU temperature-sensitive coating 5, with a coating amount of 5-10 g / m. 2 The TPU temperature-sensitive coating 5 is connected to the PCM constant-temperature hydrogel cooling layer 2. The TPU temperature-sensitive coating 5 exhibits enhanced elastic recoil force at low temperatures (<25°C), achieving a synergistic enhancement effect between cooling and pressure application. The gradient elastic pressure layer 3 has a distal end pressure of 25-30 mmHg, decreasing to 15-20 mmHg proximally. A natural latex self-adhesive layer 6 is provided on the outer surface of the breathable and waterproof backing layer 4. No chemical tackifiers are added to the natural latex self-adhesive layer 6.

[0045] The breathable and waterproof backing layer 4 is a polyurethane breathable film with a thickness of 0.05-0.08mm bonded to polyester nonwoven fabric via hot pressing, with a moisture permeability ≥3000g / m². 2 It functions 24 / 7, providing waterproof and breathable protection, blocking external moisture, and securing the entire bandage structure. The breathable and waterproof backing layer 4 is connected to the natural latex self-adhesive layer 6.

[0046] The preparation method of the PCM constant temperature cold compress and gradient pressure integrated swelling reduction bandage of the present invention is as follows: (1) Preparation of PCM hydrogel cold compress layer 2: Based on 1000 g of total mixture, add 720-780 g of deionized water and 50-80 g of glycerin to the reaction vessel and stir to mix; while stirring, slowly add 80-100 g of sodium polyacrylate and continue stirring until uniform swelling is formed to form a transparent gel matrix; premix 80-120 g of tetradecane and hexadecane eutectic mixture and heat to 40-50°C to melt to obtain C14 / C16 eutectic mixture, wherein the mass percentage of tetradecane is 5-35%, preferably 5-32% and excluding 8%-12%, and add to the gel matrix and stir at low speed until uniform; add 15-25 g of C20-C24 paraffin, 3-5 g of menthol, 2-3 g of borneol, 1-2 g of methylparaben and an appropriate amount of bright blue pigment, and continue stirring until uniform; pour into the mold, control the thickness to 3-4 mm, and cure at room temperature.

[0047] (2) Preparation of skin contact layer 1: A nonwoven fabric made of bamboo fiber and cotton was impregnated in a chitosan finishing solution and padded with a pick-up rate of 80%. The fabric was then dried at 80°C to obtain a chitosan-finished skin contact layer 1, wherein the chitosan solid content was approximately 1.5-2.0 g / m³. 2 In the chitosan finishing solution, 1.0-2.0 wt% of chitosan is dissolved in a 1% acetic acid aqueous solution, and 3.0-5.0 wt% of glycerol is added for softening finishing.

[0048] (3) Preparation of gradient elastic pressure layer 3: TPU temperature-sensitive coating 5 is formed by coating the inner surface of the spandex and polyester blended elastic webbing with TPU temperature-sensitive hot melt adhesive, with a coating amount of 5-10 g / m 2 Dry and cure.

[0049] (4) Preparation of breathable and waterproof backing layer 4: The PU breathable film is hot-pressed and laminated with polyester non-woven fabric. The thickness of the PU breathable film is 0.05-0.08 mm. The outer surface of the breathable and waterproof backing layer 4 is coated with natural latex self-adhesive layer 6 without adding chemical tackifiers and then dried.

[0050] (5) Four-layer composite: The skin contact layer 1, PCM constant temperature hydrogel cold compress layer 2, gradient elastic pressure layer 3 and breathable waterproof backing layer 4 are stacked from bottom to top. The four layers are bonded together by hot pressing at a temperature of 80-120°C, a pressure of 0.3-0.5 MPa and a time of 10-30 seconds.

[0051] (6) Cutting and packaging: Laser cut to the required specifications (width 5 cm / 7.5 cm / 10 cm, length 450 cm / roll), sealed packaging, radiation sterilization, 25 kGy γ-ray or EO sterilization.

[0052] like Figure 2 The figure shows a schematic diagram of the phase transition temperature-time curve of the C14 / C16 eutectic PCM mixture described in this invention. The horizontal axis represents time (h), and the vertical axis represents temperature (°C). The curve shows that the bandage can maintain a constant temperature plateau for ≥8 hours within the temperature range of 10-18.5°C.

[0053] This performance is ensured by the high phase transition enthalpy of the PCM eutectic mixture (ΔHm≥170 J / g, with the preferred formulation measured at 180-210 J / g) and the optimized hydrogel encapsulation structure. Taking the standard specification product (C14:C16=20:80) as an example, under room temperature (25°C) testing, the temperature of the cold compress surface rapidly drops to 13-14°C and remains constant within this temperature range for ≥8 hours, before slowly rising back to room temperature. This confirms the excellent performance of the product of this invention, which requires no refrigeration, is ready to use upon opening, and provides long-term constant-temperature cold compress.

[0054] like Figure 3 The diagram shown illustrates the gradient pressure distribution of the bandage of this invention, taking the ankle joint as an example: Apply 25-30 mmHg pressure at the distal end (ankle) to strongly promote the movement of edema fluid towards the proximal end; apply 20-25 mmHg pressure in the middle section to maintain stable compression and consolidate the swelling reduction effect; apply 15-20 mmHg pressure at the proximal end (below the knee) to avoid blocking arterial blood flow and ensure safe use.

[0055] The arrows indicate the path of edema fluid returning proximally along the lymphatic / venous system. This gradient pressure is achieved through the gradually varying weave density design of the gradient elastic pressure layer 3 and the tension control during winding. In use, the layer is spirally wound from the distal end to the proximal end, with greater tension applied at the distal end and gradually decreasing tension at the proximal end, thus obtaining the aforementioned gradient pressure distribution.

[0056] Meanwhile, the TPU temperature-sensitive coating 5 on the inner surface of the gradient elastic pressure layer 3 has enhanced elastic recoil force in low temperature (<25°C) environment. When the PCM hydrogel cold compress layer 2 releases cold energy, the TPU temperature-sensitive coating 5 automatically tightens, so that the pressure gradually increases with the extension of the cold compress time, realizing the automatic synergistic enhancement of cold compress and pressure. This mechanism has not been reported in traditional bandages.

[0057] like Figure 4 The diagram shown illustrates the usage state of the PCM constant-temperature cooling spray described in this invention. The spray contains C14 / C16 eutectic PCM microcapsules dispersed in the spray matrix. During use, the aerosol can 7 sprays the contents evenly onto the affected skin through the atomizing nozzle 8. After spraying, the PCM microcapsules adhere to the skin surface, forming a PCM microcapsule adhesion layer 9, which continuously provides a constant-temperature cooling compress of 11°C-18°C through phase change heat absorption; simultaneously, chitosan forms a chitosan film-forming protective layer 10, which has breathable, antibacterial, and moisturizing functions.

[0058] Spray formulation (based on 1000 mL): 650-720 mL deionized water; 80-120 g PCM microcapsules (melamine resin wall material, core material C14:C16=20:80, particle size 10-50 μm); 50-80 mL glycerin; 3-5 g menthol; 2-3 g borneol; 30-50 mL propylene glycol; 5-10 g chitosan (degree of deacetylation ≥90%, molecular weight ≤50 kDa); 3-5 g carbomer 940; appropriate amount of triethanolamine to adjust pH to 5.5-6.5; 1-2 g methylparaben; pure nitrogen (pressure 0.3-0.5 MPa) as propellant.

[0059] The preparation process is as follows: Carbomer 940 is dispersed in deionized water and swelled for 2 hours, and triethanolamine is added to adjust the pH; glycerol, propylene glycol, menthol, and borneol are mixed and heated to 50°C to dissolve, and after cooling, the gel matrix is ​​added; PCM microcapsules are added and stirred at low speed (200 rpm) for 5 minutes; chitosan acetate solution and methylparaben are added and stirred evenly; the mixture is filled into an aluminum aerosol can (marked 7), filled with nitrogen, and the atomizing nozzle 8 is installed.

[0060] Instructions for use: Spray evenly from a distance of 10-15 cm from the affected area for 2-3 seconds, 3-4 times daily. Each application should last 30-60 minutes and can be repeated. This spray can be used alone or in combination with a bandage: first spray for a quick cold compress, then wrap the bandage for a continuous cold compress, achieving both immediate and continuous cold compress effects.

[0061] Figure 5 This is a superimposed diagram of the DSC heating curves of the C14 / C16 eutectic PCM mixture described in this invention under 9 different ratios. Figure 5The horizontal axis represents temperature (°C), and the vertical axis represents heat flux (mW). The nine sample groups are PCM-F (C14:C16=5:95), PCM-G (10:90), PCM-H (15:85), PCM-I (17.5:82.5), PCM-A (20:80), PCM-B (25:75), PCM-C (28:72), PCM-D (32:68), and PCM-E (38:62). The overlay plot shows that as the C14 mass percentage increases from 5% to 38%, the melting peak temperature (Tpm) of the samples monotonically decreases from 18.48°C to 8.67°C, exhibiting a good monotonic correspondence. Among them, the DSC curves of the seven samples (PCM-F, PCM-H, PCM-I, PCM-A, PCM-B, PCM-C, and PCM-D) with C14 proportions ranging from 5% to 32% all showed a single endothermic peak, indicating that C14 and C16 can form a stable eutectic system within these proportions, and the latent heat of phase transformation is concentrated and released at a single temperature point. PCM-G (10:90) showed peak splitting in the overlay diagram, indicating that there is a critical transition region in the C14-C16 phase diagram near 10% C14. In view of this, the present invention defines the region with a C14 proportion of approximately 8%-12% as the critical transition region. The PCM eutectic mixture in this region does not show a single endothermic peak and is not within the preferred proportion range of the present invention. PCM-E (38:62) showed a bimodal characteristic in the overlay diagram, indicating that when the C14 proportion reaches 38%, the rotational phase transformation and melting process separate. This overlay plot comprehensively demonstrates the complete data chain of DSC curves showing a single endothermic peak within the preferred ratio range of this invention (C14:C16 = 5:95 to 32:68, excluding approximately 8%-12% of the critical transition region). The measured peak temperature range of the samples with a single endothermic peak is 10.03-18.48°C, with the lowest temperature sample being PCM-D (Tpm = 10.03°C, ΔHm = 163.79 J / g) and the highest temperature sample being PCM-F (Tpm = 18.48°C, ΔHm = 210.48 J / g), a difference of approximately 8.5°C. This covers the main temperature range required for clinical cold compresses, and the phase transition temperature can be continuously adjusted within this range by adjusting the C14 ratio.

[0062] It should be noted that, Figures 6 to 8 The horizontal axis of the raw DSC spectrum represents the instrument sampling time (min). Under programmed temperature conditions, the time axis and the temperature axis have a linear relationship. Figure 5 The temperature-heat flux curve was redrawn based on the data results table in the test report. All peak temperature values ​​in the graph have been temperature corrected and are consistent with the data results table in the test report.

[0063] Figure 6 This is a DSC temperature rise curve of the PCM-F sample (C14:C16=5:95) described in this invention. Figure 6 The horizontal axis represents sampling time (min), and the vertical axis represents heat flow (mW). This is the original curve of heat flow versus time recorded by the DSC instrument during programmed temperature rise. According to the results table in the test report, this sample exhibits a single, sharp endothermic peak at 18.48°C (melting peak temperature Tpm = 18.48°C), extrapolating the melting onset temperature Teim = 12.81°C, and the enthalpy of fusion ΔHm = 210.48 J / g, which is the highest among the nine samples. The curve's symmetrical and sharp peak shape indicates that the eutectic mixture with a low C14 ratio (5%) has the highest energy storage density and optimal concentration of phase transition temperatures, making it suitable for cooling applications in the 16-19°C temperature range. It should be noted that the horizontal axis of the original DSC spectrum represents the instrument sampling time. Under programmed temperature rise conditions, the time axis and temperature axis have a linear relationship, and the accurate phase transition peak temperature value after temperature correction is given in the data results table of the test report.

[0064] Figure 7 This is a DSC temperature rise curve of the PCM-A sample (C14:C16=20:80) described in this invention. Figure 7 The horizontal axis represents sampling time (min), and the vertical axis represents heat flow (mW). This is the original curve of heat flow versus time recorded by the DSC instrument during the programmed temperature rise process. According to the results table in the test report, the sample exhibits a single endothermic peak at 13.57°C (melting peak temperature Tpm = 13.57°C), extrapolating the melting onset temperature Teim = 4.18°C, and the enthalpy of fusion ΔHm = 180.47 J / g. The curve has a symmetrical and clean peak shape, without shoulder peaks or splitting, indicating that the eutectic system with a C14:C16 = 20:80 ratio is highly homogeneous, and the phase transition process is simple and stable. This ratio is one of the best-performing ratios in the example, suitable for standard cold compress scenarios in the 10°C -14°C temperature range. The horizontal axis of the original DSC spectrum represents sampling time, and the accurate phase transition peak temperature value after temperature correction is given in the data results table of the test report.

[0065] Figure 8 This is a DSC temperature rise curve of the PCM-E sample (C14:C16=38:62) described in this invention. Figure 8The horizontal axis represents sampling time (min), and the vertical axis represents heat flow (mW). This is the original curve of heat flow versus time recorded by the DSC instrument during programmed temperature rise. According to the results data table in the test report, the DSC temperature rise curve of this sample shows two separate endothermic peaks: the low-temperature peak appears at -9.67°C, with a melting enthalpy ΔHm = 9.51 J / g, and the high-temperature main peak appears at 8.67°C (melting enthalpy ΔHm = 144.14 J / g, extrapolated melting onset temperature Teim = 0.21°C). This double-peak phenomenon originates from the rotational phase transition of the C14-C16 isocrystalline system at high C14 content: during the transition from the ordered crystalline phase to the liquid phase, n-alkane molecules first undergo an intermediate state—the rotational phase (molecules gain rotational freedom but still maintain positional order). This process is accompanied by an independent endothermic effect, which separates from the high-temperature melting peak to form a double peak. The figure shows that when the C14 mass percentage reaches 38%, the eutectic system no longer exhibits a single endothermic peak. Therefore, the preferred upper limit of the C14 ratio in this invention is 32% to eliminate bimodal proportions and ensure the isothermal cooling performance of the PCM eutectic mixture. The horizontal axis of the original DSC spectrum represents the sampling time, and the accurate phase transition peak temperature value after temperature correction is given in the data results table of the test report.

[0066] The product of this invention can be industrially produced using conventional medical device manufacturing equipment and processes. All raw materials are pharmaceutical-grade or cosmetic-grade conventional raw materials, widely available and reasonably priced. The formulation, multi-layer lamination, cutting and packaging of the PCM hydrogel cooling layer can all be carried out on a continuous production line, making it suitable for large-scale industrial production.

[0067] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the implementation of the present invention is not limited to the above-described manner. Any improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A PCM constant temperature cold compress and gradient pressure integrated anti-swelling bandage, characterized in that, From the inside out, the following are included: Skin contact layer (1), wherein the skin contact layer is a non-woven fabric made of bamboo fiber and cotton blend, and is treated with chitosan solution; PCM constant temperature hydrogel cooling layer (2), wherein the PCM constant temperature hydrogel cooling layer is a mixture of tetradecane and hexadecane eutectic in sodium polyacrylate gel matrix as phase change material, and the phase change temperature is 10-18.5°C. Gradient elastic pressure layer (3), wherein the gradient elastic pressure layer is a spandex and polyester blended elastic webbing, and its inner surface is coated with a TPU temperature-sensitive coating (5), the pressure at the distal end is 25-30 mmHg, and decreases to 15-20 mmHg towards the proximal end; And a breathable and waterproof backing layer (4).

2. The PCM constant temperature cold compress and gradient pressure integrated swelling reduction bandage according to claim 1, characterized in that: In the PCM constant temperature hydrogel cold compress layer (2), the total PCM content is 8-12wt%, the water content is 72-78wt%, and the continuous constant temperature time is ≥8 hours.

3. The PCM constant temperature cold compress and gradient pressure integrated swelling reduction bandage according to claim 1, characterized in that: The areal density of the skin contact layer (1) is 50-80 g / m³. 2 The chitosan solution concentration is 1.0-2.0 wt%, the ethanol content is ≤5 wt%, and the pH value is 5.5-6.

5.

4. The PCM constant temperature cold compress and gradient pressure integrated swelling reduction bandage according to claim 1, characterized in that: In the tetradecane and hexadecane eutectic mixture, the mass percentage of tetradecane is 5-35% and the mass percentage of hexadecane is 65-95%.

5. The PCM constant temperature cold compress and gradient pressure integrated swelling reduction bandage according to claim 4, characterized in that: In the tetradecane and hexadecane eutectic mixture, the mass percentage of tetradecane is 5-32%, excluding 8%-12%; the mass percentage of hexadecane is 68-95%; the DSC heating curve of the tetradecane and hexadecane eutectic mixture shows a single endothermic peak with a peak temperature of 10°C-18.5°C.

6. The PCM constant temperature cold compress and gradient pressure integrated swelling reduction bandage according to claim 1, characterized in that: The coating amount of the TPU temperature-sensitive coating (5) is 5-10 g / m². 2 The TPU temperature-sensitive coating has enhanced elasticity and shrinkage force in environments below 25°C; the outer surface of the breathable and waterproof backing layer (4) is provided with a natural latex self-adhesive layer (6), and no chemical tackifiers are added to the natural latex self-adhesive layer.

7. The PCM constant temperature cold compress and gradient pressure integrated swelling reduction bandage according to claim 1, characterized in that: The breathable and waterproof backing layer (4) is composed of a polyurethane breathable film and a polyester nonwoven fabric. The thickness of the polyurethane breathable film is 0.05-0.08 mm, and the moisture permeability is ≥3000 g / m². 2 / 24h.

8. The PCM constant temperature cold compress and gradient pressure integrated swelling reduction bandage according to claim 1, characterized in that: The PCM constant temperature hydrogel cooling layer (2) also includes 1.5-2.5 wt% of C20-C24 paraffin, and 0.3-0.5 wt% of menthol and / or 0.2-0.3 wt% of borneol.

9. The PCM constant temperature cold compress and gradient pressure integrated swelling reduction bandage according to claim 1, characterized in that: The tetradecane and hexadecane eutectic mixture in the PCM constant temperature hydrogel cooling layer (2) is encapsulated using a microencapsulation process, with melamine resin or silica as the wall material and microcapsule particle size of 50-200μm.

10. A method for preparing a PCM constant temperature cold compress and gradient pressure integrated swelling-reducing bandage as described in any one of claims 1 to 9, characterized in that: Includes the following steps: Step 1, Prepare PCM hydrogel cold compress layer (2): Mix deionized water, glycerin and sodium polyacrylate until uniform swelling; add tetradecane and hexadecane eutectic mixture, stir at low speed until uniform; add additives, stir and pour into mold with a thickness of 3-4mm, and solidify. Step 2, preparation of skin contact layer (1): bamboo fiber and cotton blended nonwoven fabric is impregnated in chitosan finishing solution and dried; Step 3, prepare gradient elastic pressure layer (3): coat the inner surface of the spandex and polyester blended elastic webbing with TPU temperature-sensitive coating (5), and dry and cure; Step 4, prepare the breathable and waterproof backing layer (4): heat-press the polyurethane breathable film with the polyester nonwoven fabric. Step 5: Heat-press composite the skin contact layer (1), PCM constant temperature hydrogel cold compress layer (2), gradient elastic pressure layer (3), and breathable waterproof backing layer (4) in that order; Step six: Cut the packaging.

11. The preparation method according to claim 10, characterized in that: In step one, based on 1000 g of total mixture, deionized water is 720-780 g, glycerin is 50-80 g, sodium polyacrylate is 80-100 g, and a tetradecane and hexadecane eutectic mixture is 80-120 g, wherein the mass percentage of tetradecane is 5-32%, but 8%-12% is excluded; the auxiliary agents include 15-25 g of C20-C24 paraffin, 3-5 g of menthol, 2-3 g of borneol, 1-2 g of methylparaben, and brilliant blue pigment.

12. The preparation method according to claim 10, characterized in that: In step two, the chitosan concentration in the chitosan finishing solution is 1.0-2.0 wt%, the chitosan is dissolved in 1% acetic acid aqueous solution, and 3.0-5.0 wt% glycerol is added as a softening agent; the padding residue is 80%, and the drying temperature is 80°C.

13. The preparation method according to claim 10, characterized in that: In step three, the coating amount of the TPU temperature-sensitive coating (5) is 5-10 g / m². 2 In step four, a natural latex self-adhesive layer (6) is coated on the outer surface of the breathable and waterproof backing layer (4), wherein no chemical tackifier is added to the natural latex self-adhesive layer.

14. The preparation method according to claim 10, characterized in that: In step five, the temperature for hot pressing is 80-120°C, the pressure is 0.3-0.5 MPa, and the time is 10-30 seconds.

15. The preparation method according to claim 10, characterized in that: In step one, the tetradecane and hexadecane eutectic mixture is pre-microencapsulated before being added.

16. A PCM constant temperature cooling spray, characterized in that: include: Aerosol can (7); Atomizing nozzle (8) is provided on the aerosol can (7); and the spray matrix filled in the aerosol can (7); The spray matrix contains PCM microcapsules, the core material of which is a eutectic mixture of tetradecane and hexadecane. The mass percentage of tetradecane in the eutectic mixture is 5-32%, excluding 8%-12%; the mass percentage of hexadecane is 68-95%. The DSC temperature rise curve of the core material shows a single endothermic peak with a peak temperature of 10-18.5°C. The PCM microcapsules are dispersed in the spray matrix. The spray matrix contains thickening and suspending agents, film-forming agents, moisturizers, and propellants. After spraying, the PCM microcapsules adhere to the skin surface and provide continuous constant-temperature cooling through phase change endothermic heat absorption.

17. The PCM constant temperature cooling spray according to claim 16, characterized in that: The core material of the PCM microcapsules has a mass ratio of tetradecane to hexadecane of 5:95 to 32:68 and a phase transition temperature of 11-18°C; the wall material of the PCM microcapsules is melamine resin or silica with a particle size of 10-50 μm; and the content of PCM microcapsules in the spray matrix is ​​8-12 wt%.

18. The PCM constant temperature cooling spray according to claim 16, characterized in that: The film-forming agent is chitosan, and the content of chitosan in the spray matrix is ​​0.5-1.0 wt%; the thickening and suspending agent is carbomer 940, and the content of carbomer 940 in the spray matrix is ​​0.3-0.5 wt%; the propellant is pure nitrogen gas at a pressure of 0.3-0.5 MPa.

19. The PCM constant temperature cooling spray according to claim 16, characterized in that: The spray matrix further includes 0.3-0.5 wt% menthol and / or 0.2-0.3 wt% borneol; the pH value of the spray matrix is ​​5.5-6.

5.

20. A PCM constant temperature cooling compress kit, characterized in that: The product includes the PCM constant temperature cold compress and gradient pressure integrated swelling reduction bandage as described in any one of claims 1 to 9, and the PCM constant temperature cold compress spray as described in any one of claims 16 to 19; when using it, the spray is first sprayed onto the affected area for rapid cold compress, and then the bandage is wrapped around the affected area for continuous cold compress and pressure.

21. The use of the PCM constant temperature cold compress and gradient pressure integrated swelling-reducing bandage according to any one of claims 1 to 9 in the preparation of a medical device for physical cooling and swelling reduction after acute soft tissue injury.

Images