Cooling hydrogel and preparation method thereof
By constructing a hydrogel with a dual chemical cross-linking network, the problems of insufficient mechanical strength, adhesion and stability of hydrogel cooling patches are solved, achieving a highly efficient and safe self-supporting cooling effect, suitable for clinical and home use.
Patent Information
- Application Number
- CN202511683950.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-17
- Publication Date
- 2026-02-27
AI Technical Summary
Existing hydrogel cooling patches suffer from low mechanical strength, poor adhesion, poor thermal conductivity, and insufficient stability, resulting in poor cooling effects and safety hazards, making it difficult to meet the long-lasting and comfortable cooling needs of clinical and home use scenarios.
By introducing components such as multi-hydroxy polymers, water-soluble vinyl monomers, and vinyl zwitterionic monomers, a dual chemical cross-linking network is constructed to form a multi-cross-linking structure with covalent cross-linking and functional groups working together, thereby improving mechanical strength and adhesion, and enhancing water retention capacity and stability through hydrophilic components.
It achieves structural integrity without external support, possesses excellent thermal conductivity and self-adhesion, significantly improves heat dissipation efficiency and long-term stability, and achieves rapid cooling effect of more than 3°C within half an hour.
Smart Images
Figure CN121574483A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the fields of functional polymer materials and biomedical engineering technology, and in particular to a cooling hydrogel and its preparation method. Background Technology
[0002] In current clinical management of fever symptoms, in addition to the routine use of oral antipyretics and analgesics, physical cooling is widely used as a safe and non-invasive adjunctive treatment in the nursing care of various febrile patients. Traditional physical cooling methods mainly include ice packs, cold compresses, and alcohol rubs. However, these methods generally suffer from problems such as cumbersome operation, short cooling duration, and the need for repeated changes or repetitions. Furthermore, some methods (such as alcohol rubs) pose risks of skin irritation, allergies, and even toxicity absorption, limiting their long-term and widespread application in home and clinical settings.
[0003] In recent years, hydrogels, as a semi-solid flexible material with high water content and good biocompatibility, have shown broad application prospects in the fields of thermal regulation and localized cooling. Their excellent thermal conductivity and soft, comfortable feel make them an ideal transdermal cooling medium. Currently, several hydrogel-based fever-reducing patches have been launched on the market, but most products still face significant technical bottlenecks.
[0004] Currently available hydrogel cooling patches generally use non-woven fabric as a support substrate. This is primarily because the hydrogel itself has low mechanical strength and lacks self-supporting ability, requiring an external substrate to maintain structural integrity. However, non-woven fabric itself has poor thermal conductivity, forming a thermal resistance layer that severely hinders effective heat exchange between the hydrogel and the skin, thus significantly weakening the actual cooling effect. Furthermore, to enhance the user's cooling sensation, some products add highly volatile ingredients (such as menthol derivatives). However, because these substances have poor water solubility, they often require organic solvents (such as ethanol and propylene glycol) for dissolution, which can easily cause adverse reactions such as skin irritation, redness, and allergies, posing a safety risk, especially to infants and people with sensitive skin.
[0005] More importantly, there is often a trade-off between the mechanical properties and adhesive properties of hydrogel materials. To improve mechanical strength and achieve a substrate-free self-supporting structure, it is usually necessary to increase the cross-linking density or introduce rigid components. However, this often leads to a decrease in material elasticity and a deterioration in interfacial wettability, thereby significantly reducing its adhesion to the skin. Good adhesion is a prerequisite for ensuring that the cooling patch does not fall off during human activity and maintains continuous contact, which directly affects the product's practicality and user experience.
[0006] Furthermore, the long-term stability of hydrogels is also a crucial factor affecting product quality. Moisture loss not only leads to product shrinkage and failure but can also cause packaging contamination or inconvenience due to liquid seepage. The water-locking capacity of hydrogels primarily depends on the hydrophilicity of the polymer network and the density of the three-dimensional cross-linked structure. Insufficient cross-linking or an improper hydrophilic-hydrophobic balance can easily lead to water seepage or excessively rapid water loss during storage, severely impacting shelf life and performance.
[0007] In summary, constructing a hydrogel cooling material that combines good mechanical strength, excellent skin adhesion, efficient heat dissipation, and long-term stability without relying on a nonwoven fabric substrate with poor thermal conductivity has become a key technological challenge in developing next-generation practical physical cooling products. Therefore, there is an urgent need to provide a novel hydrogel system that can synergistically optimize these multiple performance indicators, overcome the performance bottlenecks of existing products, and meet the pressing needs for safe, long-lasting, and comfortable cooling products in both clinical and home settings. Summary of the Invention
[0008] To address the aforementioned technical problems, embodiments of the present invention provide a cooling hydrogel and its preparation method. The technical solution is as follows:
[0009] This invention provides a cooling hydrogel. The raw material components for preparing the cooling hydrogel, by mass percentage, include: 2%-4% polyhydroxy polymer, 4%-7.1% water-soluble vinyl monomer, 0.55%-1.6% vinyl zwitterionic monomer, 0-7% glycerol, 3%-10% crosslinking agent, 0.2%-0.5% thickener, 0.6%-1.2% solidifying agent, 0-0.1% initiator, and the balance being deionized water.
[0010] This invention utilizes free radical polymerization to synergistically construct a hydrogel network with a dual chemical crosslinking structure. Under the action of an initiator, water-soluble vinyl monomers copolymerize with vinyl zwitterionic monomers to form a hydrophilic polymer backbone. During this process, a divinyl crosslinking agent, N,N'-methylenebisacrylamide, is introduced. Its two carbon-carbon double bonds can simultaneously participate in the free radical growth reactions of different polymer chains, forming covalent crosslinking nodes in three-dimensional space, constituting the first layer of crosslinking network, providing the hydrogel with basic mechanical strength and anti-swelling ability.
[0011] Simultaneously, glycidyl methacrylate in the system participates in free radical polymerization via its vinyl groups, grafting epoxy groups onto the polymer backbone; while the polyhydroxy polymer provides a large number of hydroxyl functional groups. During the polymerization reaction, especially under heating or suitable pH conditions, the epoxy groups undergo ring-opening addition reactions with adjacent hydroxyl groups to generate stable ether bonds, thereby forming a second chemical crosslinking between different polymer chains. Although this crosslinking mechanism belongs to a stepwise post-crosslinking mechanism, it occurs in parallel with the free radical polymerization process in the reaction system, interpenetrating and synergistically constructing with the bisacrylamide crosslinking network.
[0012] These two chemical cross-linking networks form synchronously in space and reinforce each other, which not only improves the overall cross-linking density and mechanical strength, but also optimizes its elasticity, fatigue resistance and long-term stability, achieving properties such as unsupported self-support, high adhesion and long-term use of the cooling hydrogel.
[0013] Optionally, the polyhydroxy polymer is one or more of polyvinyl alcohol, sodium alginate, or polyglycerol.
[0014] Polyvinyl alcohol, sodium alginate, and polyglycerol are all rich in hydroxyl groups, which can undergo ring-opening addition reactions with glycidyl methacrylate, a functional monomer containing epoxy groups, to form a stable ether-linked cross-linked structure. This reaction is a non-radical chemical cross-linking, which can further enhance the cross-linking density after the main chain covalent network is formed, constructing a "second cross-linking network" and significantly improving the structural compactness and long-term stability of the hydrogel.
[0015] Optionally, the water-soluble vinyl monomer is N,N'-dimethylacrylamide or acrylamide.
[0016] Both N,N-dimethylacrylamide and acrylamide contain highly polar amide groups (-CONH2 or -CON(CH3)2), which can form a hydrophilic backbone structure rich in hydrogen bond acceptors and donors after polymerization, giving the polymer network high hydrophilicity. High water-holding capacity not only helps maintain the product's morphological stability during storage but also supports its continuous heat absorption through slow water evaporation, achieving a long-lasting cooling effect while enhancing the cooling sensation and skin comfort during application. Both monomers contain carbon-carbon double bonds that can participate in free radical polymerization, enabling efficient initiation of polymerization reactions under the action of heat, light, or chemical initiators. They also exhibit good copolymerization activity and compatibility with the zwitterionic monomer [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide and glycidyl methacrylate containing epoxy groups, allowing for uniform embedding into the copolymer backbone. Meanwhile, the polymer backbone constructed from N,N-dimethylacrylamide or acrylamide has high segmental flexibility and can form physical crosslinking points through intermolecular hydrogen bonds, giving the hydrogel good extensibility and resilience. In the multi-crosslinking system of the present invention, the hydrophilic backbone acts as a "soft segment," while the covalent crosslinking network formed by the divinyl crosslinking agent and the chemical crosslinking between epoxy groups and polyhydroxy polymers act as "hard points" to provide structural strength. This rigid-flexible synergistic network structure achieves an optimized balance of mechanical properties, significantly improving the tensile strength, tear resistance, and fatigue resistance of the hydrogel, enabling it to maintain its complete structure even without external nonwoven fabric support.
[0017] Optionally, the vinyl zwitterionic monomer is [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide or 2-methacryloyloxyethyl phosphocholine.
[0018] Both [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide and 2-methacryloyloxyethylphosphocholine contain equal amounts of positively and negatively charged groups, forming a stable dipole system. This system can associate with water molecules through strong electrostatic interactions, forming a highly ordered "bound water layer." Its water-holding capacity far exceeds that of ordinary hydrophilic polymers, allowing the hydrogel to effectively inhibit the migration and precipitation of free water even in a high water content state, greatly improving the material's stability and long-term storage reliability. High water retention not only prevents hardening, cracking, or adhesion loss during use but also ensures continuous water evaporation and heat dissipation, thus achieving a stable and lasting physical cooling effect. Furthermore, these zwitterionic monomers can specifically bind to charged amino acid residues in the stratum corneum of the skin through ion-dipole or electrostatic interactions, and the polar functional groups can form a multiple hydrogen bond network with hydroxyl and amino groups on the skin surface, giving the hydrogel excellent self-adhesive properties, achieving a firm adhesion to the skin without relying on traditional pressure-sensitive adhesives. Meanwhile, the strong polar side groups of the zwitterionic monomer can induce the formation of dynamic physical crosslinking points between polymer chains. This, in conjunction with the covalent network constructed by the divinyl crosslinking agent and the chemical crosslinking formed by the epoxy-hydroxyl reaction, further enhances the overall mechanical strength of the hydrogel, enabling it to maintain its structural integrity even under nonwoven fabric support.
[0019] Optionally, the crosslinking agent is one or more of glycidyl methacrylate, N,N'-methylenebisacrylamide, or polyethylene glycol diglycidyl ether.
[0020] N,N'-Methylenebisacrylamide is a typical divinyl crosslinking agent, with acrylamide groups (-CH=CH2) at both ends of its molecule that can participate in free radical polymerization. Under the action of an initiator, N,N'-methylenebisacrylamide can bridge different polymer chains to form stable carbon-carbon bonds, thereby constructing a high-density covalent crosslinked network in three-dimensional space. This network provides initial structural support for the hydrogel, endowing the material with excellent swelling resistance, tensile strength, and dimensional stability.
[0021] Glycidyl methacrylate possesses polymerization activity and functional convertibility. Its methacryloyl group can readily participate in free radical copolymerization, stably attaching epoxy functional groups to the polymer backbone. Subsequently, under suitable conditions (such as heating or an alkaline environment), this epoxy group can undergo ring-opening addition reactions with hydroxyl-rich macromolecules in the system, generating ether-linked cross-linked structures. This process does not depend on free radical reactions and belongs to a "post-cross-linking" mechanism, which can further enhance the cross-linking density after the main network is formed.
[0022] Polyethylene glycol diglycidyl ether, with an epoxy group at each end of its molecule, is a typical bifunctional epoxy compound. It can undergo a nucleophilic ring-opening reaction with the -OH groups in polyhydroxy polymers under heating or weakly alkaline conditions to form stable covalent crosslinking bridges. Furthermore, the polyethylene glycol segments in polyethylene glycol diglycidyl ether have good flexibility and hydrophilicity, which not only helps to alleviate the embrittlement problem caused by excessive crosslinking, but also improves the elasticity, wettability, and skin comfort of the hydrogel. In addition, the polyethylene glycol segment structure has a certain water retention capacity, which can synergistically inhibit water migration and precipitation.
[0023] Optionally, the thickener is one or more of sodium carboxymethyl cellulose, polyvinylpyrrolidone, hydroxypropyl starch, gum arabic, or guar gum.
[0024] By introducing an appropriate amount of thickener, its long-chain polymers fully swell in water and form a three-dimensional network structure, significantly increasing the viscosity and shear resistance of the hydrogel precursor solution, effectively inhibiting particle sedimentation and component segregation. The thickener molecular chains can form segmental entanglements with the main polymer network, forming non-covalent physical cross-linking points, which can effectively improve the elastic modulus, tensile strength, and deformation capacity of the hydrogel. Furthermore, the abundant hydrophilic groups of the thickener can form strong hydrogen bonds with water molecules, effectively binding free water and restricting the migration of water molecules, thereby significantly inhibiting the "water separation" phenomenon caused by osmotic pressure difference.
[0025] Optionally, the solidifying agent is one or more of carrageenan, agar, or gelatin. Carrageenan, agar, and gelatin are all naturally derived high-molecular-weight polysaccharides or proteins with excellent gelling properties, biocompatibility, and environmental responsiveness. They can impart high elastic modulus and compressive strength to hydrogels, thereby enhancing their overall rigidity.
[0026] Optionally, the initiator is one or more of α-ketoglutaric acid, ammonium persulfate, or potassium persulfate. α-ketoglutaric acid, ammonium persulfate, or potassium persulfate can all effectively initiate free radical polymerization reactions, promoting the copolymerization and crosslinking of vinyl monomers such as N,N-dimethylacrylamide and zwitterionic monomers.
[0027] The present invention also provides a method for preparing the above-described cooling hydrogel, comprising the following steps:
[0028] S1: A hydrogel precursor solution is obtained by mixing a polyhydroxy polymer, a water-soluble vinyl monomer, a vinyl zwitterionic monomer, a thickener, a crosslinking agent, a solidifying agent, an initiator, and deionized water.
[0029] S2: The precursor solution is cross-linked to form a three-dimensional network structure by energy initiation, thereby obtaining the cooling hydrogel.
[0030] Optionally, the energy triggering method includes:
[0031] Photoinitiation, wherein the light intensity of the photoinitiation is 1500-2500 μW / cm². 2 The illumination time is 30-50 minutes; or,
[0032] Thermal initiation, wherein the heating temperature for thermal initiation is 50-70℃ and the heating time is 30-90mm; or,
[0033] Radiation-induced, wherein the radiation dose is 30-40 kGy and the radiation time is 10-30 min.
[0034] The beneficial effects of the technical solutions provided by the embodiments of the present invention include at least the following:
[0035] The cooling hydrogel and its preparation method provided in this invention introduce polymer monomers and macromolecules containing functional groups, endowing the hydrogel with abundant interfacial interaction sites, significantly improving its adhesion to the skin, and achieving a firm fit without pressure-sensitive adhesive. Simultaneously, the polymer chains synergistically construct a multi-network structure through covalent cross-linking and reactive cross-linking of functional groups, giving the material excellent mechanical properties. Mechanical strength reaches 122 kPa, elongation at break exceeds 270%, peel strength exceeds 29.68 N / m, and initial tack reaches the level of a No. 10 small ball in the national standard GB / T 4852-2002. It can achieve self-supporting molding without a substrate, avoiding the obstruction of heat conduction by non-woven fabric and other backing materials in traditional cooling patches, significantly improving heat dissipation efficiency, and achieving a rapid cooling effect of more than 3°C within half an hour. Furthermore, the multi-crosslinked network structure and the excellent hydrophilicity of each component give the hydrogel excellent water retention capacity, with no water seepage under normal temperature, refrigerated (4°C), and frozen (-20°C) storage conditions, demonstrating good long-term stability. The precursor liquid can be initially cured and shaped at room temperature after injection molding, which facilitates the final polymerization by subsequent light exposure or heating. The operation is simple and conducive to continuous and large-scale industrial production. Attached Figure Description
[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0037] Figure 1 This is the infrared spectrum of the cooling hydrogel prepared in Example 1. Detailed Implementation
[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0039] Example 1
[0040] The present invention provides a cooling hydrogel, the raw material components of which include: 0.4g polyvinyl alcohol, 1g glycerol, 0.8g N,N-dimethylacrylamide, 0.2g [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide, 0.04g sodium carboxymethyl cellulose, 0.01g glycidyl methacrylate, 0.01g N,N'-methylenebisacrylamide, 0.08g polyethylene glycol diglycidyl ether, 0.1g carrageenan, 0.01g α-ketoglutaric acid; the balance being water.
[0041] The preparation method of this cooling hydrogel includes the following steps:
[0042] S1: A hydrogel precursor solution is obtained by mixing a polyhydroxy polymer, a water-soluble vinyl monomer, a vinyl zwitterionic monomer, a thickener, a crosslinking agent, a solidifying agent, an initiator, and deionized water.
[0043] Step S1 specifically includes the following steps:
[0044] S11: Matrix preparation: Weigh 0.4 g polyvinyl alcohol 124 and 1 g glycerol and dissolve them in deionized water at 70°C. Then add 0.1 g carrageenan and 0.04 g sodium carboxymethyl cellulose to the flask and stir until homogeneous.
[0045] S12: Addition of monomers: Add 0.8g N,N-dimethylacrylamide and 0.2g [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide to the flask in step S11 and stir at 70°C for 15 minutes, then add 0.01g glycidyl methacrylate;
[0046] S13: Addition of crosslinking agent: Add 0.01g N,N'-methylenebisacrylamide and 0.08g polyethylene glycol diglycidyl ether to the flask in step S12 and stir evenly at 70°C;
[0047] S14: Addition of initiator: Add 0.01g of α-ketoglutaric acid to the flask in step S13 and stir at 70℃ for 5min to obtain hydrogel precursor solution;
[0048] S2: The precursor solution is cross-linked to form a three-dimensional network structure by energy initiation, thereby obtaining the cooling hydrogel.
[0049] Step S2 specifically includes the following steps:
[0050] S21: Injection Molding: The prepared hydrogel precursor solution is injected into a transparent mold while still hot and at a uniform speed. The mold is then heated using an ultraviolet lamp (wavelength: 365nm, light intensity: 2000μW / cm²). 2 Irradiate for 40 minutes to form the shape.
[0051] Performance testing: At room temperature, the initial tack test with a No. 10 ball (GB / T-4852-2002) showed a peel strength of 29.68 N / m, a mechanical strength of 122 kPa, and a tensile strength at break of 270%.
[0052] Example 2
[0053] The present invention provides a cooling hydrogel, the raw material components of which include: 0.3g polyvinyl alcohol 1799, 0.64g N,N-dimethylacrylamide, 0.16g [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide, 0.04g sodium carboxymethyl cellulose, 0.01g glycidyl methacrylate, 0.08g N,N'-methylenebisacrylamide, 0.06g polyethylene glycol diglycidyl ether, 0.1g carrageenan, 0.08g α-ketoglutaric acid; the balance being water.
[0054] The preparation method of this cooling hydrogel includes the following steps:
[0055] S1: A hydrogel precursor solution is obtained by mixing a polyhydroxy polymer, a water-soluble vinyl monomer, a vinyl zwitterionic monomer, a thickener, a crosslinking agent, a solidifying agent, an initiator, and deionized water.
[0056] Step S1 specifically includes the following steps:
[0057] S11: Matrix preparation: Weigh 0.3g of polyvinyl alcohol 1799 and dissolve it in deionized water at 70℃. Then add 0.1g of carrageenan and 0.04g of sodium carboxymethyl cellulose to the flask and stir until homogeneous.
[0058] S12: Addition of monomers: Add 0.64g N,N-dimethylacrylamide and 0.16g [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide to the flask in step S11 and stir at 70°C for 15 minutes, then add 0.01g glycidyl methacrylate;
[0059] S13: Addition of crosslinking agent: Add 0.08g N,N'-methylenebisacrylamide and 0.06g polyethylene glycol diglycidyl ether to the flask in step S12 and stir evenly at 70°C;
[0060] S14: Addition of initiator: Add 0.008 g of α-ketoglutaric acid to the flask in step S13 and stir at 70 °C for 5 min to obtain hydrogel precursor solution;
[0061] S2: The precursor solution is cross-linked to form a three-dimensional network structure by energy initiation, thereby obtaining the cooling hydrogel.
[0062] Step S2 specifically includes the following steps:
[0063] S21: Injection Molding: The prepared hydrogel precursor solution is injected into a transparent mold while still hot and at a uniform speed. The mold is then heated using an ultraviolet lamp (wavelength: 365nm, light intensity: 2000μW / cm²). 2 Irradiate for 40 minutes to form the shape.
[0064] Performance testing: At room temperature, the initial tack test with a No. 9 ball (GB / T-4852-2002) showed a peel strength of 25.49 N / m, a mechanical strength of 102 kPa, and a tensile strength at break of 252%.
[0065] Example 3
[0066] The present invention provides a cooling hydrogel, the raw material components of which include: 0.4g polyvinyl alcohol 1788, 1g glycerol, 1.0g N,N-dimethylacrylamide, 0.2g [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonic acid propyl)ammonium hydroxide, 0.03g sodium carboxymethyl cellulose, 0.01g glycidyl methacrylate, 0.01g N,N'-methylenebisacrylamide, 0.08g polyethylene glycol diglycidyl ether, 0.1g carrageenan, 0.15g α-ketoglutaric acid; the balance being water.
[0067] The preparation method of this cooling hydrogel includes the following steps:
[0068] S1: A hydrogel precursor solution is obtained by mixing a polyhydroxy polymer, a water-soluble vinyl monomer, a vinyl zwitterionic monomer, a thickener, a crosslinking agent, a solidifying agent, an initiator, and deionized water.
[0069] Step S1 specifically includes the following steps:
[0070] S11: Matrix preparation: Weigh 0.4g of polyvinyl alcohol 1799 and 1g of glycerol and dissolve them in deionized water at 70℃. Then add 0.1g of carrageenan and 0.03g of sodium carboxymethyl cellulose to the flask and stir until homogeneous.
[0071] S12: Addition of monomers: Add 1.0g N,N-dimethylacrylamide and 0.2g [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide to the flask in step S11 and stir at 70°C for 15 minutes, then add 0.01g glycidyl methacrylate;
[0072] S13: Addition of crosslinking agent: Add 0.01g N,N'-methylenebisacrylamide and 0.08g polyethylene glycol diglycidyl ether to the flask in step S12 and stir evenly at 70°C;
[0073] S14: Addition of initiator: Add 0.015g of α-ketoglutaric acid to the flask in step S13 and stir at 70℃ for 5 min to obtain hydrogel precursor solution;
[0074] S2: The precursor solution is cross-linked to form a three-dimensional network structure by energy initiation, thereby obtaining the cooling hydrogel.
[0075] Step S2 specifically includes the following steps:
[0076] S21: Injection Molding: The prepared hydrogel precursor solution is injected into a transparent mold while still hot and at a uniform speed. The mold is then heated under a UV lamp (wavelength: 365 nm, light intensity: 2500 μW / cm²). 2 Irradiate for 30 minutes to form the shape.
[0077] Performance testing: At room temperature, the initial tack test with a No. 9 ball (GB / T-4852-2002) showed a peel strength of 25.17 N / m, a mechanical strength of 116 kPa, and a tensile strength at break of 256%.
[0078] Example 4
[0079] The present invention provides a cooling hydrogel, the raw material components of which include: 0.5g sodium alginate, 1g glycerol, 0.85g N,N-dimethylacrylamide, 0.15g [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonic acid propyl)ammonium hydroxide, 0.04g polyvinylpyrrolidone K30, 0.01g glycidyl methacrylate, 0.012g N,N'-methylenebisacrylamide, 0.1g carrageenan, 0.01g α-ketoglutaric acid; the balance being water.
[0080] The preparation method of this cooling hydrogel includes the following steps:
[0081] S1: A hydrogel precursor solution is obtained by mixing a polyhydroxy polymer, a water-soluble vinyl monomer, a vinyl zwitterionic monomer, a thickener, a crosslinking agent, a solidifying agent, an initiator, and deionized water.
[0082] Step S1 specifically includes the following steps:
[0083] S11: Matrix preparation: Weigh 0.5g of sodium alginate and dissolve it in deionized water at 70℃. Then add 0.1g of carrageenan and 0.04g of polyvinylpyrrolidone K30 to the flask and stir until homogeneous.
[0084] S12: Addition of monomers: Add 0.85g N,N-dimethylacrylamide and 0.15g [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide to the flask in step S11 and stir at 70°C for 15 minutes, then add 0.01g glycidyl methacrylate;
[0085] S13: Addition of crosslinking agent: Add 0.012 g of N,N'-methylenebisacrylamide to the flask in step S12 and stir evenly at 70 °C;
[0086] S14: Addition of initiator: Add 0.01g of α-ketoglutaric acid to the flask in step S13 and stir at 70℃ for 5min to obtain hydrogel precursor solution;
[0087] S2: The precursor solution is cross-linked to form a three-dimensional network structure by energy initiation, thereby obtaining the cooling hydrogel.
[0088] Step S2 specifically includes the following steps:
[0089] S21: Injection Molding: The prepared hydrogel precursor solution is injected into a transparent mold while still hot and at a uniform speed. The mold is then heated under a UV lamp (wavelength: 365 nm, light intensity: 2500 μW / cm²). 2 Irradiate for 30 minutes to form the shape.
[0090] Performance testing: At room temperature, the initial tack test with a No. 10 ball (GB / T-4852-2002) showed a peel strength of 29.68 N / m, a mechanical strength of 122 kPa, and a tensile strength at break of 270%.
[0091] Example 5
[0092] The present invention provides a cooling hydrogel, the raw material components of which include: 0.4g polyvinyl alcohol 124, 1g glycerol, 0.8g N,N-dimethylacrylamide, 0.2g [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonic acid propyl)ammonium hydroxide, 0.03g sodium carboxymethyl cellulose, 0.01g glycidyl methacrylate, 0.01g N,N'-methylenebisacrylamide, 0.06g polyethylene glycol diglycidyl ether, 0.15g carrageenan, 0.01g Irgacure 2959; the balance being water.
[0093] The preparation method of this cooling hydrogel includes the following steps:
[0094] S1: A hydrogel precursor solution is obtained by mixing a polyhydroxy polymer, a water-soluble vinyl monomer, a vinyl zwitterionic monomer, a thickener, a crosslinking agent, a solidifying agent, an initiator, and deionized water.
[0095] Step S1 specifically includes the following steps:
[0096] S11: Matrix preparation: Weigh 0.4g of polyvinyl alcohol 124 and dissolve it in deionized water at 70℃. Then add 0.15g of carrageenan and 0.03g of sodium carboxymethyl cellulose to the flask and stir until homogeneous.
[0097] S12: Addition of monomers: Add 0.8g N,N-dimethylacrylamide and 0.2g [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide to the flask in step S11 and stir at 70°C for 15 minutes, then add 0.01g glycidyl methacrylate;
[0098] S13: Addition of crosslinking agent: Add 0.01g N,N'-methylenebisacrylamide and 0.06g polyethylene glycol diglycidyl ether to the flask in step S12 and stir evenly at 70°C;
[0099] S14: Addition of initiator: Add 0.01g Irgacure 2959 to the flask in step S13 and stir at 70℃ for 5 min to obtain hydrogel precursor solution;
[0100] S2: The precursor solution is cross-linked to form a three-dimensional network structure by energy initiation, thereby obtaining the cooling hydrogel.
[0101] Step S2 specifically includes the following steps:
[0102] S21: Injection Molding: The prepared hydrogel precursor solution is injected into a transparent mold while still hot and at a uniform speed. The mold is then heated using an ultraviolet lamp (wavelength: 365 nm, light intensity: 2000 μW / cm²).2 Irradiate for 40 minutes to form the shape.
[0103] Performance testing: At room temperature, the initial tack test with a No. 10 ball (GB / T-4852-2002) showed a peel strength of 29.12 N / m, a mechanical strength of 115 kPa, and a tensile strength at break of 261%.
[0104] Example 6
[0105] The present invention provides a cooling hydrogel, the raw material components of which include: 0.4g polyvinyl alcohol 124, 1g glycerol, 0.8g N,N-dimethylacrylamide, 0.2g [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonic acid propyl)ammonium hydroxide, 0.04g sodium carboxymethyl cellulose, 0.01g glycidyl methacrylate, 0.012g N,N'-methylenebisacrylamide, 0.06g polyethylene glycol diglycidyl ether, 0.1g carrageenan; the balance being water.
[0106] The preparation method of this cooling hydrogel includes the following steps:
[0107] S1: A hydrogel precursor solution is obtained by mixing a polyhydroxy polymer, a water-soluble vinyl monomer, a vinyl zwitterionic monomer, a thickener, a crosslinking agent, a solidifying agent, an initiator, and deionized water.
[0108] Step S1 specifically includes the following steps:
[0109] S11: Matrix preparation: Weigh 0.4g of polyvinyl alcohol 124 and dissolve it in deionized water at 70℃. Then add 0.15g of carrageenan and 0.04g of sodium carboxymethyl cellulose to the flask and stir until homogeneous.
[0110] S12: Addition of monomers: Add 0.8g N,N-dimethylacrylamide and 0.2g [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide to the flask in step S11 and stir at 70°C for 15 minutes, then add 0.01g glycidyl methacrylate;
[0111] S13: Addition of crosslinking agent: Add 0.012g N,N'-methylenebisacrylamide and 0.06g polyethylene glycol diglycidyl ether to the flask in step S12 and stir evenly at 70°C to obtain a hydrogel precursor solution;
[0112] S2: The precursor solution is cross-linked to form a three-dimensional network structure by energy initiation, thereby obtaining the cooling hydrogel.
[0113] Step S2 specifically includes the following steps:
[0114] S21: Injection molding: The prepared hydrogel precursor solution is injected into a transparent mold while hot and at a uniform speed, and then irradiated with an electron accelerator (intensity: 40 kGy) for 30 minutes to form the mold.
[0115] Performance testing: At room temperature, the initial tack test with a No. 10 ball (GB / T-4852-2002) showed a peel strength of 28.64 N / m, a mechanical strength of 120 kPa, and a tensile strength at break of 248%.
[0116] Comparative Example 1:
[0117] (1) Matrix preparation
[0118] Weigh 0.4 g of polyvinyl alcohol 124 and 1 g of glycerol and dissolve them in deionized water at 70°C. Then add 0.1 g of carrageenan and 40 mg of sodium carboxymethyl cellulose to the flask and stir until homogeneous.
[0119] (2) Addition of polymer monomers
[0120] Continue adding 0.2 g of [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide to the flask and stirring at 70°C for 15 minutes, then add 10 mg of glycidyl methacrylate.
[0121] (3) Addition of crosslinking agent
[0122] Add 10 mg N,N'-methylenebisacrylamide and 80 mg polyethylene glycol diglycidyl ether to the flask and stir until homogeneous at 70°C.
[0123] (4) Addition of initiator
[0124] Add 10 mg of α-ketoglutarate to the flask and stir at 70 °C for 5 min to obtain the hydrogel precursor solution.
[0125] (5) Injection molding
[0126] While still hot, inject the mixture into a transparent mold at a uniform speed and irradiate it with an ultraviolet lamp (wavelength: 365 nm, light intensity 2000 μW / cm2) for 40 minutes.
[0127] Performance testing: At room temperature, the initial tack test with a No. 9 ball (GB / T-4852-2002) showed a peel strength of 26.60 N / m, a mechanical strength of 31 kPa, and a tensile strength at break of 330%.
[0128] Comparative Example 2:
[0129] (1) Matrix preparation
[0130] Weigh 0.4 g of polyvinyl alcohol 124 and 1 g of glycerol and dissolve them in deionized water at 70°C. Then add 0.1 g of carrageenan and 40 mg of sodium carboxymethyl cellulose to the flask and stir until homogeneous.
[0131] (2) Addition of polymer monomers
[0132] Continue adding 0.8 g of N,N-dimethylacrylamide to the flask and stirring at 70°C for 15 minutes, then add 10 mg of glycidyl methacrylate.
[0133] (3) Addition of crosslinking agent
[0134] Add 10 mg N,N'-methylenebisacrylamide and 80 mg polyethylene glycol diglycidyl ether to the flask and stir until homogeneous at 70°C.
[0135] (4) Addition of initiator
[0136] Add 10 mg of α-ketoglutarate to the flask and stir at 70 °C for 5 min to obtain the hydrogel precursor solution.
[0137] (5) Injection molding
[0138] While still hot, inject the mixture into a transparent mold at a uniform speed and irradiate it with an ultraviolet lamp (wavelength: 365 nm, light intensity 2000 μW / cm2) for 40 minutes.
[0139] Performance testing: At room temperature, the initial tack test with No. 8 small balls (GB / T-4852-2002) showed a peel strength of 21.24 N / m, a mechanical strength of 114 kPa, and a tensile strength at break of 258%.
[0140] like Figure 1As shown, the infrared spectral analysis of the cooling hydrogel prepared in Example 1 indicates that during the material synthesis process, not only did the free radical polymerization of the carbon-carbon double bonds in the water-soluble vinyl monomers (such as N,N-dimethylacrylamide) occur, but a ring-opening polymerization reaction between the epoxy groups and hydroxyl groups was also observed. These two types of chemical reactions together construct a cross-linked system with a multi-network structure, thereby endowing the hydrogel with excellent comprehensive properties. A systematic study of Examples 1 to 6 revealed that the prepared hydrogel exhibits good mechanical properties, with a mechanical strength as high as 122 kPa, an elongation at break as high as 270%, and a peel strength as high as 29.68 N / m or more. Furthermore, the initial tack meets the test requirements for a No. 10 steel ball in the national standard GB / T 4852-2002, demonstrating strong surface adhesion. In addition, this material can achieve self-supporting molding without relying on an external support substrate, exhibiting excellent structural stability and practicality. The results of comparison between Comparative Example 1 and Comparative Example 2 further demonstrate that the introduction of water-soluble vinyl monomers and vinyl zwitterionic monomers ([2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide) into the formulation plays a key role in regulating the crosslinking density, hydrophilicity, and intermolecular interactions of the hydrogel, significantly affecting its final mechanical properties, adhesion properties, and network structure integrity, thus confirming the critical role of these two functional monomers in constructing high-performance cooling hydrogels.
[0141] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.
Claims
1. A cooling hydrogel, characterized in that, The raw material components for preparing the cooling hydrogel, by mass percentage, include: 2%-4% polyhydroxy polymer, 4%-7.1% water-soluble vinyl monomer, 0.55%-1.6% vinyl zwitterionic monomer, 0-7% glycerol, 3%-10% crosslinking agent, 0.2%-0.5% thickener, 0.6%-1.2% solidifying agent, 0-0.1% initiator, and the balance being deionized water.
2. The cooling hydrogel according to claim 1, characterized in that, The polyhydroxy polymer is one or more of polyvinyl alcohol, sodium alginate, or polyglycerol.
3. The cooling hydrogel according to claim 1, characterized in that, The water-soluble vinyl monomer is N,N'-dimethylacrylamide or acrylamide.
4. The cooling hydrogel according to claim 1, characterized in that, The vinyl zwitterionic monomer is [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide or 2-methacryloyloxyethyl choline phosphate.
5. The cooling hydrogel according to claim 1, characterized in that, The crosslinking agent is glycidyl methacrylate, N,N'-methylenebisacrylamide, or polyethylene glycol diglycidyl ether.
6. The cooling hydrogel according to claim 1, characterized in that, The thickener is one or more of sodium carboxymethyl cellulose, polyvinylpyrrolidone, hydroxypropyl starch, gum arabic, or guar gum.
7. The cooling hydrogel according to claim 1, characterized in that, The solidifying agent is one or more of carrageenan, agar, or gelatin.
8. The cooling hydrogel according to claim 1, characterized in that, The initiator is one or more of α-ketoglutaric acid, ammonium persulfate, or potassium persulfate.
9. A method for preparing a cooling hydrogel according to any one of claims 1-8, characterized in that, Includes the following steps: S1: Mix the polyhydroxy polymer, water-soluble vinyl monomer, vinyl zwitterionic monomer, glycidyl methacrylate, divinyl crosslinking agent, thickener, solidifying agent, initiator and deionized water to obtain a hydrogel precursor solution. S2: The precursor solution is cross-linked to form a three-dimensional network structure by energy initiation, thereby obtaining the cooling hydrogel.
10. The preparation method according to claim 9, characterized in that, The energy triggering methods include: Photoinitiation, wherein the light intensity of the photoinitiation is 1500-2500 μW / cm². 2 The illumination time is 30-50 minutes; or, Thermal initiation, wherein the heating temperature for thermal initiation is 50-70℃ and the heating time is 30-90mm; or, Radiation-induced, wherein the radiation dose is 30-40 kGy and the radiation time is 10-30 min.