Preparation method of polyurethane condom with delay effect

Abstract

The invention discloses a preparation method of a polyurethane condom with a time-delay effect, the problems in the traditional time-delay condom technology are solved by adopting a supported time-delay additive microcapsule structure, and the time-delay additive is coated in a biodegradable high polymer material shell layer such as chitosan, gelatin, polylactic acid and the like, so that the time-delay effect of the polyurethane condom is improved. The microcapsule with the particle size of 0.5-5 microns is formed, the slow-release function is effectively achieved, the shell layer of the microcapsule protects the time-delay auxiliary agent from being influenced by the external environment, the stability of the auxiliary agent is remarkably improved, the duration time of the time-delay effect is prolonged, meanwhile, the microcapsule is evenly dispersed in the polyurethane film, gradual release of the time-delay auxiliary agent can be achieved, and the slow-release effect of the time-delay auxiliary agent is improved. In addition, the biodegradable shell layer of the microcapsule can be gradually decomposed after being used and cannot be left in the human body or on the surface of the skin, the safety is high, and the practicability and the user experience of the product are further improved.

Description

Technical Field

[0001] The invention relates to the technical field of condom preparation methods, and more specifically, to a method for preparing a polyurethane condom with a time-delay effect. Background Art

[0002] At present, most of the delayed ejaculation condoms widely used in the market achieve the delayed ejaculation effect by coating the inner surface with local anesthetics (such as lidocaine or benzocaine). These anesthetics can delay ejaculation by reducing the sensitivity of nerve endings, thereby achieving the purpose of delayed ejaculation. However, such traditional delayed ejaculation condoms have certain technical limitations.

[0003] The anesthetics in traditional delayed-release condoms are usually directly coated, which can easily lead to the following problems: the release rate of the anesthetic is difficult to control, which may cause excessive local numbness or discomfort due to rapid release, affecting the user experience; the anesthetic is directly exposed to the external environment and is easily degraded by air, humidity, etc., resulting in a weakened or unstable delay effect; the anesthetic is unevenly distributed on the surface of the condom, which may lead to an uneven delay effect. In addition, the directly coated anesthetic may cause local irritation due to excessively high concentrations, and even affect the mechanical properties of the condom.

[0004] Therefore, in view of the above technical problems, it is necessary to provide a method for preparing a polyurethane condom with a delayed effect. Summary of the invention

[0005] The object of the present invention is to provide a method for preparing a polyurethane condom with a delayed effect to solve the above-mentioned problem.

[0006] In order to achieve the above purpose, the technical solution provided by an embodiment of the present invention is as follows:

[0007] A method for preparing a polyurethane condom with a delayed effect comprises the following steps:

[0008] S1: preparing a polyurethane raw material solution containing a time-delay function, wherein a loaded time-delay auxiliary agent microcapsule is added to achieve a sustained release of the time-delay auxiliary agent;

[0009] S2: coating the polyurethane raw material solution on the surface of the condom mold to form a uniform polyurethane film;

[0010] S3: cross-linking and curing the film to evenly embed the time-delay additive microcapsules into the polyurethane matrix;

[0011] S4: peeling the solidified film from the mold to obtain a polyurethane condom with a delayed effect;

[0012] S5: Cleaning, drying, lubricating and packaging the obtained condoms.

[0013] As a further improvement of the present invention, the preparation method of the loaded delay aid microcapsules in S1 can use the delay aid as the core, and adopt emulsion polymerization or interfacial polymerization to coat the shell layer with chitosan, gelatin, polylactic acid or its copolymer to prepare loaded delay aid microcapsules with a particle size of 0.5-5 microns.

[0014] As a further improvement of the present invention, the time-delay adjuvant in S1 is selected from local anesthetics, including lidocaine or benzocaine, and is coated in microcapsules to achieve sustained release.

[0015] As a further improvement of the present invention, the addition amount of the time-delay auxiliary agent is 0.5%-5% of the total mass of the polyurethane raw material solution.

[0016] As a further improvement of the present invention, the polyurethane raw material solution in S1 comprises a polyurethane prepolymer, a chain extender, a time-delay aid microcapsule and a solvent, wherein the polyurethane prepolymer is prepared by reacting an isocyanate with a polyether polyol or a polyester polyol, and the isocyanate is preferably 2,4-toluene diisocyanate (TDI) or 4,4'-diphenylmethane diisocyanate (MDI).

[0017] As a further improvement of the present invention, the chain extender is a diamine compound or a diol compound, preferably ethylenediamine or 1,4-butanediol.

[0018] As a further improvement of the present invention, in S2, the polyurethane raw material solution is coated on the surface of the condom mold by dipping or spraying, and a surfactant is added during the coating process, and the film thickness is controlled to be 0.01-0.03 mm.

[0019] As a further improvement of the present invention, when the film is cross-linked and cured in S3, a heating curing or a moisture curing method is adopted, and the heating curing temperature is 50-80° C. and the time is 10-30 minutes.

[0020] As a further improvement of the present invention, in S4, a release agent coating is added to the mold surface.

[0021] As a further improvement of the present invention, the lubrication treatment in S5 is performed by uniformly coating the surface of the condom with a liquid containing a delayed-release lubricant, wherein the lubricant is selected from silicone oil or hydrophilic gel, and vacuum sealing or nitrogen filling protection is adopted during the packaging process.

[0022] Compared with the prior art, the advantages of the present invention are:

[0023] The present invention solves the above-mentioned problems in the traditional time-delay condom technology by adopting a loaded delay agent microcapsule structure. The time-delay agent is coated in a shell layer of biodegradable polymer materials such as chitosan, gelatin, and polylactic acid to form a microcapsule with a particle size of 0.5-5 microns, which effectively realizes the function of sustained release. The shell layer of the microcapsule protects the time-delay agent from the influence of the external environment, significantly improves the stability of the agent, and prolongs the duration of the delay effect. At the same time, the microcapsules are evenly dispersed in the polyurethane film, which can realize the gradual release of the time-delay agent and avoid the discomfort or excessive numbness caused by instantaneous release. In addition, the biodegradable shell layer of the microcapsule can be gradually decomposed after use and will not remain in the human body or on the skin surface, so it is highly safe. Through this structural design, the time-delay condom of the present invention not only significantly enhances the stability and uniformity of the delay effect, but also takes into account comfort and mechanical properties, further improving the practicality and user experience of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic structural diagram of the polyurethane condom preparation method of the present invention;

[0025] Figure 2 It is a data schematic diagram of multiple embodiments of the present invention. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments, and all other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making creative work are within the scope of protection of the present invention.

[0027] Embodiment 1:

[0028] See also Figure 1 , a method for preparing a polyurethane condom with a delayed effect, comprising the following steps:

[0029] S1: preparing a polyurethane raw material solution containing a time-delay function, wherein a loaded time-delay auxiliary agent microcapsule is added to achieve a sustained release of the time-delay auxiliary agent;

[0030] S2: coating the surface of the condom mold with a polyurethane raw material solution to form a uniform polyurethane film;

[0031] S3: cross-linking and curing the film to evenly embed the time-delay additive microcapsules into the polyurethane matrix;

[0032] S4: peeling the solidified film from the mold to obtain a polyurethane condom with a delayed effect;

[0033] S5: Cleaning, drying, lubricating and packaging the obtained condoms.

[0034] Among them, by adopting a loaded delay aid microcapsule structure, the above-mentioned problems in the traditional delay condom technology are solved. By coating the delay aid in a shell layer of biodegradable polymer materials such as chitosan, gelatin, and polylactic acid, a microcapsule with a particle size of 0.5-5 microns is formed, which effectively realizes the function of sustained release. The shell layer of the microcapsule protects the delay aid from the influence of the external environment, significantly improves the stability of the aid, and prolongs the duration of the delay effect. At the same time, the microcapsules are evenly dispersed in the polyurethane film, which can realize the gradual release of the delay aid and avoid discomfort or excessive numbness caused by instantaneous release. In addition, the biodegradable shell layer of the microcapsule can be gradually decomposed after use and will not remain in the human body or on the skin surface, so it is highly safe. Through this structural design, the delay condom of the present invention not only significantly enhances the stability and uniformity of the delay effect, but also takes into account comfort and mechanical properties, further improving the practicality and user experience of the product.

[0035] The preparation method of the loaded delay aid microcapsule in S1 can use the delay aid as the core, and adopt emulsion polymerization or interfacial polymerization to coat the shell layer with chitosan, gelatin, polylactic acid or its copolymer to prepare the loaded delay aid microcapsule with a particle size of 0.5-5 microns.

[0036] Among them, the preparation method of the loaded delay aid microcapsules in S1 is an innovative technology that uses microencapsulation technology to encapsulate the delay aid in a polymer shell to achieve sustained release of the delay aid. Specifically, this method uses the delay aid as the core material and utilizes emulsion polymerization or interfacial polymerization to construct a shell layer composed of biodegradable polymer materials such as chitosan, gelatin, polylactic acid or its copolymers.

[0037] The prepared loaded time-delay agent microcapsules have a particle size range of 0.5-5 microns and have excellent particle size uniformity and shell stability. The realization of this microcapsule technology can effectively prolong the release time of the time-delay agent, reduce its degradation rate when directly exposed to the external environment, and avoid numbness or discomfort caused by high concentrations of the time-delay agent in contact with the human body.

[0038] The time-delay additive is used as the core and is coated with a polymer shell by emulsion polymerization or interfacial polymerization. For example, in the emulsion polymerization method, the time-delay additive is dispersed in the oil phase or the water phase to form an emulsion, and the polymerization reaction is initiated at the interface to polymerize chitosan, gelatin, polylactic acid and other materials to form a dense shell layer; the interfacial polymerization method forms microcapsules by cross-linking or polymerization of the shell precursor at the interface of two immiscible phases.

[0039] The particle size of microcapsules (0.5-5 microns) is mainly achieved by adjusting the shear force, dispersant concentration, and reaction conditions (such as temperature and time) in the emulsion system. Precise control of particle size can not only ensure the uniform dispersion of the time-delay additive, but also optimize its sustained release performance and biocompatibility.

[0040] The prepared microcapsules have a stable shell structure, and the time-delay additive in the core is released through diffusion of the shell or gradual degradation of the shell. The sustained-release mechanism can achieve the continuous release of the time-delay additive over a long period of time, and gradually exert the time-delay effect during use, rather than instantaneous release that causes the effect to be too strong or disappear too quickly.

[0041] The shell material has good biodegradability and can be gradually decomposed into substances that are harmless to the human body after use. It will not remain in the body or on the skin surface and is highly safe.

[0042] Through microencapsulation technology, the delay additive can be slowly released during use, avoiding the problem of excessive delay or too short a delay due to instantaneous release in traditional technology, thereby significantly extending the duration of the delay effect and improving user experience and satisfaction.

[0043] The time-delaying auxiliary agent in S1 is selected from local anesthetics, including lidocaine or benzocaine, and is coated in microcapsules to achieve sustained release.

[0044] Among them, the delay aid in S1 is selected from local anesthetics, including lidocaine or benzocaine, and the sustained release is achieved through microencapsulation technology. The local anesthetics lidocaine and benzocaine are used as delay aids, which can delay ejaculation by temporarily reducing the sensitivity of nerve endings to achieve a delay effect. The microencapsulation technology is used to encapsulate them in biocompatible polymer materials (such as chitosan, gelatin or polylactic acid) to form a shell layer, which can effectively control the release rate of the delay aid and achieve slow release.

[0045] The sustained-release mechanism of microcapsule coating can avoid the rapid release effect of local anesthetics due to direct contact with the skin, thereby reducing the excessive numbness or discomfort that may be caused by high-concentration exposure to anesthetics. At the same time, the sustained-release extends the duration of the delayed effect and ensures that the effect is uniform and gentle without causing adverse stimulation to the user. In addition, the biodegradable properties of the coating shell material ensure safety during and after use, and no harmful residues will be produced on the skin surface or in the body.

[0046] Delay aids can not only significantly improve the delay function of condoms, but also improve the comfort and safety of use, avoiding the discomfort or uneven effects that may occur when traditional delay aids are used directly.

[0047] The added amount of the time-delay additive is 0.5%-5% of the total mass of the polyurethane raw material solution.

[0048] Among them, the addition amount of the delay agent is 0.5%-5% of the total mass of the polyurethane raw material solution. The design of this range can achieve the best balance between the delay effect, safety and product performance. When the addition amount of the delay agent is less than 0.5%, the effective dose of its sustained release may be insufficient, and it is difficult to significantly prolong the ejaculation time, resulting in an unclear delay effect; and when the addition amount exceeds 5%, it may cause excessive local anesthetic concentration, resulting in excessive numbness or discomfort of the user's skin, and even affecting the mechanical properties and uniformity of the product.

[0049] By controlling the amount of delay additive added within the range of 0.5%-5%, the significance and durability of the delay function can be ensured. At the same time, through the sustained release mechanism of the microcapsules, a mild and uniform delay effect can be achieved, avoiding the discomfort that may be caused by instantaneous release. In addition, the addition amount range has been optimized and will not have a negative impact on the mechanical properties of the polyurethane film (such as tensile strength and ductility), ensuring that the condom has excellent comfort and durability in addition to the delay function.

[0050] The polyurethane raw material solution in S1 comprises a polyurethane prepolymer, a chain extender, a time-delay agent microcapsule and a solvent, wherein the polyurethane prepolymer is prepared by reacting an isocyanate with a polyether polyol or a polyester polyol, and the isocyanate is preferably 2,4-toluene diisocyanate (TDI) or 4,4'-diphenylmethane diisocyanate (MDI).

[0051] Among them, the polyurethane raw material solution in S1 contains polyurethane prepolymer, chain extender, delay agent microcapsule and solvent, wherein the polyurethane prepolymer is prepared by the reaction of isocyanate and polyether polyol or polyester polyol, and the isocyanate is preferably 2,4-toluene diisocyanate (TDI) or 4,4'-diphenylmethane diisocyanate (MDI). The polyurethane prepolymer, as the basic material of the film, has excellent film-forming properties and mechanical properties, and can provide good flexibility, elasticity and tear resistance through the reaction of isocyanate and polyether or polyester polyol.

[0052] The addition of chain extender can further adjust the segment structure and cross-linking density of polyurethane molecules, thereby improving the strength, ductility and durability of the film; the time-delay additive microcapsules are evenly dispersed in the raw material solution, and its sustained release mechanism can gradually release the time-delay additive during use to achieve a long-lasting and mild time-delay function without affecting the uniformity and mechanical properties of the film. The role of the solvent is to adjust the viscosity of the raw material solution, ensure a smooth coating process, and help the time-delay additive microcapsules to be evenly dispersed.

[0053] By choosing 2,4-toluene diisocyanate (TDI) or 4,4'-diphenylmethane diisocyanate (MDI) as the isocyanate component, the polyurethane film can be given excellent physical properties and chemical stability, ensuring that the film has high strength while maintaining softness during use, further improving the comfort and durability of the condom. This formula design not only meets the requirements of the delay function, but also maintains the basic performance of the condom, taking into account both functionality and reliability.

[0054] The chain extender is a diamine compound or a diol compound, preferably ethylenediamine or 1,4-butanediol.

[0055] Among them, the chain extender is a diamine compound or a diol compound, preferably ethylenediamine or 1,4-butanediol, and its function is to undergo a chain extension reaction with the isocyanate group (-NCO) in the polyurethane prepolymer, adjust the segment structure and cross-linking density of the polyurethane molecule, thereby significantly improving the mechanical properties and elasticity of the polyurethane film.

[0056] As a diamine chain extender, ethylenediamine has high reactivity and can react quickly with isocyanate groups to form polyurethane segments with a higher proportion of hard segments, thereby enhancing the tensile strength and tear strength of the film; while 1,4-butanediol, as a diol chain extender, has a moderate reaction speed and can form a soft soft segment structure, giving the film excellent flexibility and ductility.

[0057] The combined use of diamine and diol compounds or their use alone can achieve a balance between the hard segment and the soft segment, making the polyurethane film both high-strength and soft and comfortable to the touch. The selection and optimization of the above chain extenders can ensure that the film has good mechanical properties while not affecting the distribution and sustained release performance of the delay agent microcapsules, thereby achieving an organic combination of the delay function and comfort of the condom.

[0058] In S2, the surface of the condom mold is coated with a polyurethane raw material solution by dipping or spraying. During the coating process, a surfactant is added and the film thickness is controlled to be 0.01-0.03 mm.

[0059] Among them, in S2, the polyurethane raw material solution is coated on the surface of the condom mold by dipping or spraying, wherein the wettability of the polyurethane raw material solution is improved by adding a surfactant, and the dispersion uniformity of the delay agent microcapsules in the solution is enhanced, thereby ensuring the uniform distribution of the delay agent during the film formation process. The dipping method immerses the mold in the polyurethane raw material solution and then slowly pulls it up to make the solution evenly adhere to the mold surface; the spraying method uses a nozzle to evenly spray the raw material solution on the mold surface. Both methods can ensure the continuity and uniformity of the film.

[0060] During the coating process, the concentration, viscosity and process parameters of the solution are strictly controlled to stably control the film thickness at 0.01-0.03 mm. This thickness range can take into account the high sensitivity and good mechanical strength of the condom, while ensuring the uniform distribution and full play of the delay-promoting function. If the film is too thin, it may lead to decreased mechanical properties and easy tearing, while if it is too thick, it may affect the comfort and touch of use. After optimized coating process and thickness control, the prepared condoms have both excellent delay effects in actual use and can meet high-performance mechanical and practical needs.

[0061] When the film is cross-linked and cured in S3, a heating curing or a moisture curing method is adopted, and the heating curing temperature is 50-80° C. and the time is 10-30 minutes.

[0062] Among them, when the film is cross-linked and cured in S3, heat curing or wet curing is used to ensure the stability and mechanical properties of the film structure. Heat curing is performed by applying a certain temperature (50-80°C) to the coated film and maintaining it for 10-30 minutes, so that the active isocyanate group (-NCO) in the polyurethane prepolymer and the active hydrogen group (-NH or -OH) in the chain extender fully react to form a dense cross-linked network structure. Wet curing gradually completes cross-linking through the reaction of moisture in the air or added moisture with the isocyanate group, which is suitable for temperature-sensitive processes and materials.

[0063] The range of heating curing temperature and time has been optimized to ensure the completeness of the film cross-linking reaction and avoid failure or decomposition of the time-delay additive microcapsules due to excessive temperature. The temperature range of 50-80°C can effectively promote the cross-linking of polyurethane while maintaining the integrity of the shell of the time-delay additive microcapsules to ensure the realization of the sustained release function; the curing time of 10-30 minutes can fully complete the cross-linking process of the film and avoid incomplete curing of the film structure affecting product performance.

[0064] Through this curing treatment method, the prepared film has excellent mechanical properties (such as high tensile strength and elongation at break) and good embedding stability of the delay additive, ensuring the durability and uniformity of the delay function, thereby meeting the high performance requirements and comfort experience of condoms during use.

[0065] In S4, a release agent coating is added to the mold surface.

[0066] Among them, in S4, a release agent coating is added to the mold surface to ensure that the polyurethane film can be smoothly peeled off from the mold surface after curing, thereby improving the demoulding efficiency and protecting the integrity of the film. The release agent coating can form an isolation interface between the mold and the film, effectively reducing the adhesion between the film and the mold surface, and avoiding tearing, deformation or uneven thickness.

[0067] The preferred release agents are silicone oil, polytetrafluoroethylene coating agents or other biodegradable release materials with good lubricity and chemical stability. These release agents are not only non-corrosive to the polyurethane film, but also can further improve the smoothness and uniformity of the film surface.

[0068] By adding a release agent coating to the mold surface, not only the efficiency and yield of the production process are improved, but also the distribution uniformity and shell integrity of the delay additive microcapsules in the film can be effectively protected, thereby ensuring the stability and continuity of the delay function while maintaining the high-quality touch and mechanical properties of the condom surface.

[0069] The lubrication treatment in S5 is to evenly coat the surface of the condom with a liquid containing a delayed-release lubricant, wherein the lubricant is selected from silicone oil or hydrophilic gel, and vacuum sealing or nitrogen filling protection is adopted during the packaging process.

[0070] Among them, the lubrication treatment in S5 is to evenly coat the surface of the condom with a liquid containing a delayed-release lubricant, wherein the lubricant is selected from silicone oil or hydrophilic gel, and vacuum sealing or nitrogen filling protection is adopted during the packaging process.

[0071] Delay lubricants may contain low concentrations of local anesthetics (such as lidocaine or benzocaine) or other ingredients that can enhance the delay effect, which can work synergistically with the delay agent microcapsules to further prolong the ejaculation time while ensuring comfort during use. Silicone oil lubricants have excellent lubricity and chemical stability and are suitable for long-term use, while hydrophilic gel lubricants have better cleanliness and biocompatibility and can be flexibly selected according to user needs.

[0072] Vacuum sealing or nitrogen filling protection during the packaging process can effectively prevent the influence of air and moisture on the delay lubricant and condom materials, extend the shelf life of the product and maintain the stability of the delay function. This lubrication treatment and packaging method not only enhances the functional experience of the condom, but also ensures the safety and ease of use of the product.

[0073] The following is the preparation of lidocaine microcapsule type time-delay polyurethane condom, comprising the following steps:

[0074] S1: Preparation of polyurethane raw material solution

[0075] Preparation of polyurethane prepolymer: 4,4'-diphenylmethane diisocyanate (MDI) and polyether polyol are reacted in a molar ratio of 2:1 to form a polyurethane prepolymer.

[0076] Preparation of loaded time-delay agent microcapsules: lidocaine was dissolved in the oil phase by emulsion polymerization, chitosan was used as the shell material, and lidocaine microcapsules with a particle size of 2 microns were formed by polymerization at the interface.

[0077] The prepared microcapsules are added to the polyurethane prepolymer solution at 2% of the total mass, and a chain extender, ethylenediamine, and an appropriate amount of solvent (such as dimethylformamide) are added, and the mixture is stirred evenly to obtain a raw material solution.

[0078] S2: Coating

[0079] The dipping method is used: the condom mold is immersed in the raw material solution and slowly pulled up to form a 0.02 mm thick polyurethane film. A surfactant is added to evenly disperse the lidocaine microcapsules.

[0080] S3: Cross-linking and curing

[0081] Curing at 50 °C for 20 min allowed the polyurethane to crosslink and form a dense film structure while ensuring that the microcapsules were embedded in the polyurethane matrix.

[0082] S4: Demolding

[0083] Silicone oil is coated on the surface of the mold as a release agent, and the cured film is peeled off to obtain a complete condom.

[0084] S5: Lubrication and packaging

[0085] The surface of the condom is evenly coated with a hydrophilic gel lubricant containing 0.5% lidocaine and the condom is vacuum-sealed and packaged.

[0086] Embodiment 2:

[0087] The following is the preparation of the benzocaine microcapsule type time-delay polyurethane condom, comprising the following steps:

[0088] S1: Preparation of polyurethane raw material solution

[0089] Preparation of polyurethane prepolymer: 2,4-toluene diisocyanate (TDI) and polyester polyol are reacted at a molar ratio of 1.8:1 to obtain a prepolymer.

[0090] Preparation of loaded time-delay agent microcapsules: using interfacial polymerization method, benzocaine was used as the core and polylactic acid was used as the shell material to prepare microcapsules with a particle size of 3 microns.

[0091] Add benzocaine microcapsules into the polyurethane prepolymer solution at 3% of the total mass, add chain extender 1,4-butanediol and solvent (such as N,N-dimethylacetamide), and stir evenly.

[0092] S2: Coating

[0093] The spraying method is adopted: the raw material solution is evenly sprayed on the mold surface through a nozzle to form a 0.03 mm thick polyurethane film to ensure the uniform distribution of benzocaine microcapsules.

[0094] S3: Cross-linking and curing

[0095] The wet curing treatment was carried out in an environment with a humidity of 60%, and the curing was carried out at room temperature for 30 minutes to complete the cross-linking reaction.

[0096] S4: Demolding

[0097] The mold surface is coated with polytetrafluoroethylene, and the cured film is peeled off to obtain a finished condom.

[0098] S5: Lubrication and packaging

[0099] Apply silicone lubricant containing 1% benzocaine and use nitrogen-filled protective packaging.

[0100] Embodiment 3:

[0101] The following is the preparation of the lidocaine and benzocaine composite delayed-release polyurethane condom, comprising the following steps:

[0102] S1: Preparation of polyurethane raw material solution

[0103] Preparation of polyurethane prepolymer: 4,4'-diphenylmethane diisocyanate (MDI) and polyether polyol are reacted at a molar ratio of 2:1 to obtain a prepolymer.

[0104] Preparation of loaded delay agent microcapsules: lidocaine and benzocaine were mixed in a ratio of 1:1, and polylactic acid was coated by emulsion polymerization to prepare composite microcapsules with a particle size of 1.5 μm.

[0105] The composite microcapsules are added into the polyurethane prepolymer solution at 4% of the total mass, and the chain extender ethylenediamine and a proper amount of solvent are added, and the mixture is stirred evenly.

[0106] S2: Coating

[0107] The dipping method is adopted: the mold is immersed in the raw material solution, and a 0.025 mm thick polyurethane film is formed after pulling.

[0108] S3: Cross-linking and curing

[0109] Heat curing at 80 °C for 10 min ensures the embedding stability of the microcapsules and the mechanical properties of the film.

[0110] S4: Demolding

[0111] Apply silicone oil as a release agent and peel off the film.

[0112] S5: Lubrication and packaging

[0113] Apply a hydrophilic gel lubricant containing 0.5% lidocaine and 0.5% benzocaine in a vacuum-sealed package.

[0114] according to Figure 2It can be seen that the time-delay effect of Example 2 and Example 3 is longer (25-30 minutes), indicating that benzocaine or its combined use with lidocaine can provide a more lasting time-delay function. The time-delay effect of Example 1 (lidocaine alone) is slightly shorter (20-25 minutes), but still meets the user's needs.

[0115] Example 3 has a mild and long-lasting delayed effect due to the combined use of lidocaine and benzocaine, and the user comfort score is the highest (9.2). The comfort scores of Examples 1 and 2 are slightly lower, but still at a high level.

[0116] The irritation reaction rate of Example 3 was the lowest (3.5%), indicating that the sustained release mechanism of the composite microcapsules effectively reduced the problem of instantaneous release of high-concentration local anesthetics.

[0117] The tensile strength of the three embodiments is greater than 30 MPa, meeting the mechanical property requirements of condoms.

[0118] The packaging sealing degree exceeds 98%, ensuring storage stability.

[0119] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0120] In addition, it should be understood that although the present specification is described according to embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that those skilled in the art can understand.

Claims

1. A method for preparing a polyurethane condom with a delayed effect, characterized in that: The following steps are involved: S1: preparing a polyurethane raw material solution containing a time-delay function, wherein a loaded time-delay auxiliary agent microcapsule is added to achieve a sustained release of the time-delay auxiliary agent; S2: coating the polyurethane raw material solution on the surface of the condom mold to form a uniform polyurethane film; S3: cross-linking and curing the film to evenly embed the time-delay additive microcapsules into the polyurethane matrix; S4: peeling the solidified film from the mold to obtain a polyurethane condom with a delayed effect; S5: Cleaning, drying, lubricating and packaging the obtained condoms.

2. The method for preparing a polyurethane condom with a delayed effect according to claim 1, characterized in that: The preparation method of the loaded delay aid microcapsule in S1 can use the delay aid as the core, and adopt emulsion polymerization or interfacial polymerization to coat the shell layer with chitosan, gelatin, polylactic acid or its copolymer to prepare the loaded delay aid microcapsule with a particle size of 0.5-5 microns.

3. The method for preparing a polyurethane condom with a delayed effect according to claim 1, characterized in that: The time-delay adjuvant in S1 is selected from local anesthetics, including lidocaine or benzocaine, and is coated in microcapsules to achieve sustained release.

4. The method for preparing a polyurethane condom with a delayed effect according to claim 1, characterized in that: The added amount of the time-delay auxiliary agent is 0.5%-5% of the total mass of the polyurethane raw material solution.

5. The method for preparing a polyurethane condom with a delayed effect according to claim 1, characterized in that: The polyurethane raw material solution in S1 comprises a polyurethane prepolymer, a chain extender, a time-delay agent microcapsule and a solvent, wherein the polyurethane prepolymer is prepared by reacting an isocyanate with a polyether polyol or a polyester polyol, and the isocyanate is preferably 2,4-toluene diisocyanate (TDI) or 4,4'-diphenylmethane diisocyanate (MDI).

6. The method for preparing a polyurethane condom with a delayed effect according to claim 5, characterized in that: The chain extender is a diamine compound or a diol compound, preferably ethylenediamine or 1,4-butanediol.

7. The method for preparing a polyurethane condom with a delayed effect according to claim 1, characterized in that: In S2, the polyurethane raw material solution is coated on the surface of the condom mold by dipping or spraying. During the coating process, a surfactant is added and the film thickness is controlled to be 0.01-0.03 mm.

8. The method for preparing a polyurethane condom with a delayed effect according to claim 1, characterized in that: When the film is cross-linked and cured in S3, a heating curing or a moisture curing method is adopted, and the heating curing temperature is 50-80° C. and the time is 10-30 minutes.

9. The method for preparing a polyurethane condom with a delayed effect according to claim 1, characterized in that: In the S4, a release agent coating is added on the mold surface.

10. The method for preparing a polyurethane condom with a delayed effect according to claim 1, characterized in that: The lubrication treatment in S5 is to uniformly coat the surface of the condom with a liquid containing a delayed-release lubricant, wherein the lubricant is selected from silicone oil or hydrophilic gel, and vacuum sealing or nitrogen filling protection is adopted during the packaging process.

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