A modified antibacterial polyurethane condom and its preparation method

Abstract

This invention provides a modified antibacterial polyurethane condom and its preparation method. The modified antibacterial polyurethane condom includes a polyurethane substrate layer and a functional coating. The polyurethane substrate layer includes a konjac glucomannan-polyurethane composite, a composite antibacterial agent, and modified nano-zinc oxide. The functional coating includes chitosan quaternary ammonium salt and hyaluronic acid. The chitosan quaternary ammonium salt in the functional coating is connected to the polyurethane substrate layer via covalent bonds formed through biocatalysis, and these covalent bonds are formed through the biocatalytic action of laccase. This modified antibacterial polyurethane condom exhibits low allergenicity, long-lasting antibacterial effect, and good mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of condom manufacturing technology, specifically to a modified antibacterial polyurethane condom and its preparation method. Background Technology

[0002] Polyurethane (PU) is gradually replacing natural latex as the core material for high-end condoms due to its advantages such as no risk of latex protein allergy, thinness, toughness, transparency, and good thermal conductivity. To enhance sexual health protection, modified antibacterial properties have become a research hotspot for polyurethane condoms. However, existing technologies face numerous technical bottlenecks in material compatibility, process optimization, and functional balance, making it difficult to achieve a balance between industrial application and clinical needs.

[0003] In existing technologies, antibacterial agents exhibit poor compatibility with polyurethane substrates. Conventional small-molecule antibacterial agents or nano-antibacterial fillers (such as nano-zinc oxide) are prone to aggregation and phase separation. Physically blended antibacterial agents easily migrate to human mucous membranes, causing irritation. Natural antibacterial agents (such as propyl gallate) are easily decomposed and deactivated during conventional high-temperature curing processes of polyurethane, failing to achieve long-lasting antibacterial effects. Furthermore, some existing technologies employ single-antibacterial agent modification, resulting in a narrow antibacterial spectrum and short duration of action. Other existing technologies utilize plasma grafting for surface modification, which, while improving coating adhesion, is demanding, costly, and prone to damaging the substrate's mechanical properties. In addition, insufficient optimization of the compatibility between bio-based materials and polyurethane leads to an imbalance between the substrate's mechanical properties and antibacterial performance, failing to meet relevant standards for testing.

[0004] Therefore, the development of a modified antibacterial polyurethane condom that combines low allergenicity, long-lasting antibacterial effect, good mechanical properties, and economical processing has become an urgent need in the industry. Summary of the Invention

[0005] To address the problems of poor compatibility between antibacterial agents and substrates, imbalance between antibacterial function and mechanical properties, demanding surface modification processes, and insufficient long-term antibacterial effect in existing modified antibacterial polyurethane condoms, this invention provides a modified antibacterial polyurethane condom and its preparation method, achieving a balance between low allergenicity, long-lasting antibacterial effect, and good mechanical properties.

[0006] On one hand, the present invention provides a modified antibacterial polyurethane condom, comprising a polyurethane substrate layer and a functional coating; the polyurethane substrate layer comprises a konjac glucomannan-polyurethane composite, a composite antibacterial agent, and modified nano zinc oxide; the functional coating comprises chitosan quaternary ammonium salt and hyaluronic acid; wherein the chitosan quaternary ammonium salt in the functional coating is connected to the polyurethane substrate layer through covalent bonds formed by biocatalysis.

[0007] In one embodiment, the reaction raw materials for preparing the konjac glucomannan-polyurethane composite include modified konjac glucomannan, polycaprolactone diol, hexamethylene diisocyanate, 1,6-hexanediol, and polyethylene glycol diglycidyl ether; wherein the modified konjac glucomannan is konjac glucomannan modified with glycidyltrimethylammonium chloride, and the molecular weight of the modified konjac glucomannan is 50,000-80,000.

[0008] In one embodiment, the mass ratio of the reaction raw materials is modified konjac glucomannan: polycaprolactone diol: hexamethylene diisocyanate: 1,6-hexanediol: polyethylene glycol diglycidyl ether = 1: (8-10): (3-4): (0.8-1.2): (0.3-0.5).

[0009] In one embodiment, the compound antibacterial agent includes propyl gallate and lysozyme.

[0010] In one embodiment, the mass ratio of propyl gallate to lysozyme in the composite antibacterial agent is (2.4-6):1, and / or the amount of the composite antibacterial agent added is 1.5-2.3% of the total mass of the polyurethane substrate layer.

[0011] As one embodiment, the modified nano zinc oxide is nano zinc oxide modified with KH-560 silane coupling agent, and / or the amount of the modified nano zinc oxide added is 1-3% of the total mass of the polyurethane substrate layer.

[0012] In one embodiment, the mass ratio of the chitosan quaternary ammonium salt to the hyaluronic acid in the functional coating is (0.5-1.2):(1.0-1.5).

[0013] In one embodiment, the thickness of the functional coating is 50-100 nm.

[0014] On the other hand, the present invention provides a method for preparing a modified antibacterial polyurethane condom, wherein the chitosan quaternary ammonium salt in the functional coating is connected to the polyurethane substrate layer through covalent bonds formed by biocatalysis, and the covalent bonds are formed by the biocatalytic action of laccase.

[0015] In one embodiment, the mass ratio of the laccase to the chitosan quaternary ammonium salt is (0.4-0.6):(0.8-1.2).

[0016] The modified antibacterial polyurethane condom provided in this application has the following advantages:

[0017] (1) This invention employs a composite antibacterial agent composed of propyl gallate (PG) and lysozyme (LZM). Through the synergistic antibacterial effect of PG membrane disruption and LZM enzymatic hydrolysis, it achieves full coverage inhibition of the core pathogenic bacteria. Furthermore, it is combined with modified nano zinc oxide to assist in antibacterial action, thereby enhancing the inhibitory effect on drug-resistant pathogenic bacteria. At the same time, the composite antibacterial agent is compounded in an appropriate ratio and the amount added is controlled to ensure synergistic antibacterial efficiency and avoid excessive stimulation or insufficient stimulation of components leading to antibacterial failure. Relying on the polyurethane-KGM network structure, it can achieve long-lasting antibacterial effect without significant component migration.

[0018] (2) The antibacterial components and modified nano zinc oxide of the present invention are uniformly dispersed without damaging the structure of the polyurethane substrate layer. This can effectively avoid the mechanical property degradation caused by traditional antibacterial modification. At the same time, the presence of the network structure can improve the deformation resistance of the polyurethane substrate layer and is suitable for the use of condoms.

[0019] (3) In the functional coating of the present invention, chitosan quaternary ammonium salt (HTCC) forms covalent bonds with the substrate through laccase-catalyzed biocatalysis, and then forms a film with hyaluronic acid (HA) through hydrogen bonding. It has strong adhesion and no peeling during use, thus solving the technical problem of poor stability of traditional physical coatings. At the same time, the two are compounded in an appropriate ratio and the coating thickness is controlled, which can improve the comfort of condom use while taking into account the surface antibacterial enhancement and lubrication and moisturizing functions.

[0020] (4) All the components used in this invention have good biocompatibility. Modified KGM, HTCC and HA are all low-allergenic materials, and PG and LZM are natural antibacterial components. After proper dispersion, there is no risk of mucosal discomfort. Moreover, the mild laccase-catalyzed grafting process avoids the destruction of components by high temperature and strong chemical reagents, and there are no toxic by-product residues, which meet medical safety standards.

[0021] (5) The overall preparation process of this invention does not require special high-end equipment. Laccase grafting, network structure forming and other processes are mild and controllable, and the cost is lower than that of traditional processes. Attached Figure Description

[0022] Figure 1 This is a flowchart illustrating the preparation process of the modified polyurethane condom of this invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0024] To illustrate the technical solution of the present invention, specific embodiments are described below.

[0025] On one hand, the present invention provides a modified antibacterial polyurethane condom, comprising a polyurethane substrate layer and a functional coating; the polyurethane substrate layer comprises a konjac glucomannan-polyurethane composite, a composite antibacterial agent and modified nano zinc oxide; the functional coating comprises chitosan quaternary ammonium salt and hyaluronic acid; wherein the chitosan quaternary ammonium salt in the functional coating is connected to the polyurethane substrate layer through covalent bonds formed by biocatalysis.

[0026] Specifically, the polyurethane substrate layer includes a konjac glucomannan-polyurethane composite, a composite antibacterial agent, and modified nano-zinc oxide. The konjac glucomannan-polyurethane composite (i.e., KGM-polyurethane composite) is the main matrix material in the polyurethane substrate layer. Specifically, konjac glucomannan (KGM) modified with glycidyltrimethylammonium chloride can interweave with polyurethane to form a network structure composite material. It should be noted that the two are not simply physically mixed; the network structure indicates that the two polymer segments can interpenetrate and form a stable three-dimensional network structure through hydrogen bonds and covalent bonds (unmodified KGM, although containing a large number of hydroxyl groups, has dense and highly polar intermolecular hydrogen bonds, making it prone to aggregation and difficult to dissolve in the polyurethane prepolymer system, thus unable to form a uniform interweaving; while...). This invention utilizes KGM modified with glycidyltrimethylammonium chloride, which breaks the intramolecular / intermolecular hydrogen bonds in KGM. The quaternary ammonium cationic groups introduced during modification repel some of the polar hydroxyl groups on the KGM molecular chain, weakening the hydrogen bonding and allowing the KGM segments to unfold from the aggregated state, providing space for penetration and interweaving with polyurethane segments. In addition, a large number of hydroxyl groups are still retained on the KGM molecular chain, while new quaternary ammonium groups are added. These active groups can form chemical bonds with multiple polyurethane segments (rather than simply physical mixing). The KGM-polyurethane composite has both the biocompatibility of KGM and the good mechanical properties of polyurethane.

[0027] Specifically, the combined use of compound antibacterial agents (equivalent to biological antibacterial agents) and modified nano zinc oxide (equivalent to physical antibacterial agents) can achieve complementary antibacterial effects. Because nano zinc oxide is a nano-sized particle with a large specific surface area and high surface energy, it can be adsorbed on the surface of bacteria and disrupt the integrity of bacterial cell membranes through electrostatic interactions, causing the cell membranes to lose osmotic pressure balance, leading to bacterial swelling and rupture, resulting in leakage of bacterial contents and death. At the same time, nano zinc oxide can release a small amount of zinc ions, inhibiting bacterial DNA replication and blocking the reproduction process. It is effective against a variety of pathogens, especially drug-resistant pathogens (Escherichia coli, Staphylococcus aureus, and Neisseria gonorrhoeae). On this basis, the use of compound antibacterial agents can further disrupt the bacterial cell membrane and cell wall, ensuring the antibacterial effect of the condom. However, nano-zinc oxide, being inorganic nanoparticles (30-50 nm in diameter), has densely packed and highly polar hydroxyl groups on its surface, resulting in poor compatibility with the organic polyurethane-KGM composite. Nano-zinc oxide easily aggregates with the organic polyurethane-KGM composite through hydrogen bonds, making it impossible to disperse uniformly within the organic phase. Therefore, KH-560 silane coupling agent is needed for surface modification of nano-zinc oxide. Essentially, this involves introducing organic segments onto the surface of the inorganic nanoparticles through hydrolysis and grafting reactions to eliminate interfacial compatibility differences. During the KH-560 modification process, the KH-560 molecule contains active groups at both ends (one end being a hydrolyzable alkoxy group, and the other end being...). The epoxy groups, after hydrolysis, undergo a condensation reaction with the alkoxy groups on the surface of nano-zinc oxide to form stable covalent bonds, thus grafting the epoxy groups onto the surface of nano-zinc oxide. These epoxy groups are organic functional groups, compatible with the amino groups of polyurethane segments and the hydroxyl groups of KGM, breaking down the interfacial barrier between inorganic particles and the organic phase. This allows for the uniform dispersion of nanoparticles (modified nano-zinc oxide) in the polyurethane-KGM composite in the organic phase, preventing agglomeration and internal defects, and ensuring stable mechanical properties of the substrate. If unmodified nano-zinc oxide particles are used, they are prone to agglomeration, leading to stress concentration within the substrate, decreased elongation at break, and surface powder residue, which is detrimental to condom applications. Simultaneously, the modified nano-zinc oxide introduces epoxy groups on its surface. These groups can undergo a weak chemical reaction with the isocyanate groups (-NCO) of the polyurethane prepolymer and the hydroxyl groups of KGM under mild conditions (35-40℃), forming chemical bonds that fix the modified nano-zinc oxide particles onto both polymer segments.Specifically, the epoxy group has a three-membered ring structure with high ring strain and strong polarity, making it susceptible to attack by nucleophiles containing lone pairs of electrons (the hydroxyl group of KGM), resulting in a ring-opening reaction. After the epoxy ring opens, the hydrogen atom in the KGM hydroxyl group transfers to the oxygen atom of the epoxy group, reforming the hydroxyl group. Simultaneously, the KGM molecular chain is connected to the surface of the nano-zinc oxide via ether bonds. This reaction does not require a catalyst and can occur slowly under mild conditions of 35-40℃. In addition, the -NCO group (a highly active electrophilic agent) in the polyurethane prepolymer undergoes a cycloaddition reaction with the epoxy group. After the epoxy ring opens, it forms a six-membered ring structure with the -NCO group. This ring structure firmly connects the surface of the nano-zinc oxide to the polyurethane chain segments through heterocyclic chemical bonds. In the system with an NCO / OH molar ratio of 1.3-1.6, the reaction can proceed spontaneously but at a slow rate, preventing the nanoparticles from agglomerating due to excessively vigorous reactions. Instead, it can fill the gaps in the ether bond connections. The network structure of the polyurethane-KGM composite can encapsulate the uniformly dispersed nano-zinc oxide particles in the gaps between the networks, further restricting the movement and aggregation of nanoparticles, ensuring the stability of the substrate after molding, reducing the migration of antibacterial components in condoms, and lowering the risk of mucosal irritation.

[0028] Specifically, the functional coating, applied to the surface of the polyurethane substrate layer, forms the outermost functional structure of the condom. This coating comprises chitosan quaternary ammonium salt and hyaluronic acid. The chitosan quaternary ammonium salt (HTCC) is a derivative of chitosan modified by quaternization. It exhibits superior water solubility compared to unmodified chitosan and also possesses broad-spectrum antibacterial properties (mechanism similar to nano-zinc oxide), biocompatibility, and positive charge characteristics. Furthermore, it can be covalently bonded to the surface of the polyurethane substrate layer, preventing migration. Hyaluronic acid (HA), a natural polysaccharide containing numerous hydrophilic groups, can rapidly absorb moisture from the environment, forming a uniformly thick hydrated lubricating film. This hydrated film has an extremely low coefficient of friction, significantly reducing frictional damage during use and improving comfort. It can also form hydrogen bonds with HTCC, ensuring coating density and enhancing lubrication durability, thus guaranteeing the structural stability of the functional coating. Most importantly, HTCC is covalently bonded to the polyurethane substrate layer, and the stable covalent bonds prevent HTCC migration or the entire functional coating from detaching.

[0029] In short, this invention further enhances the overall antibacterial effect of condoms by introducing biological and physical antibacterial agents into the polyurethane substrate layer and antibacterial components into the functional coating, thereby solving the problems of insufficient antibacterial effect and safety concerns associated with polyurethane condoms.

[0030] In one embodiment, the reaction raw materials for preparing the konjac glucomannan-polyurethane composite include modified konjac glucomannan, polycaprolactone diol, hexamethylene diisocyanate, 1,6-hexanediol, and polyethylene glycol diglycidyl ether; wherein the modified konjac glucomannan is konjac glucomannan modified with glycidyltrimethylammonium chloride, and the molecular weight of the modified konjac glucomannan is 50,000-80,000.

[0031] Specifically, modified konjac glucomannan forms the basic framework for the network structure. The introduced quaternary ammonium groups enhance compatibility with polyurethane, providing rigid support and dispersion sites, laying the foundation for the antibacterial components. Polycaprolactone diol (PCL) forms the core of the soft segments of the polyurethane, providing flexibility and preventing the konjac glucomannan-polyurethane composite from becoming too brittle, thus ensuring the tensile properties of the condom. Hexamethylene diisocyanate (HDI) forms the core of the hard segments of the polyurethane chain, providing highly active -NCO groups that react with the hydroxyl groups of PCL, 1,6-hexanediol, and modified KGM to form crosslinking sites, which is crucial for constructing the polyurethane chain. 1,6-hexanediol is used as a chain extender to regulate the length of the polyurethane chain and optimize the mechanical toughness and strength of the composite. Polyethylene glycol diglycidyl ether (PEGDE) is used as a crosslinking regulator. The crosslinking regulator pre-crosslinks with modified KGM to form a preliminary network framework, which is then crosslinked with the polyurethane chain to construct a stable, doubly crosslinked network structure, improving the overall integrity of the composite.

[0032] Specifically, the molecular weight of modified konjac glucomannan can be any value within the range of 50,000-80,000, such as 50,000, 60,000, 70,000, or 80,000.

[0033] To balance the structural stability, molding processability, and mechanical properties of the konjac glucomannan-polyurethane composite network structure, the molecular weight of the modified konjac glucomannan is controlled within a specific range. If the molecular weight is below 50,000, the molecular segments of the modified konjac glucomannan are too short to form a continuous network framework, resulting in poor interpenetration and cross-linking with the polyurethane segments, and a decrease in the mechanical properties of the composite (reduced elongation at break), failing to meet the stretching requirements of condoms. If the molecular weight is above 80,000, the molecular segments of the modified konjac glucomannan are prone to entanglement, leading to decreased water solubility and easy agglomeration during pre-cross-linking, resulting in abnormal viscosity of the impregnation solution, rough surface of the substrate after molding, and low processing qualification rate. Furthermore, the entanglement of the segments causes uneven porosity in the network structure, affecting the uniform dispersion of antibacterial components. Controlling the molecular weight of the modified konjac glucomannan within the range of 50,000-80,000 ensures that the KGM segments are extended and do not entangle, allowing for sufficient interpenetration and cross-linking with the polyurethane segments to form a stable network composite with a balance of rigidity and flexibility and good dispersibility.

[0034] In one implementation method, the mass ratio of the reaction raw materials is modified konjac glucomannan: polycaprolactone diol: hexamethylene diisocyanate: 1,6-hexanediol: polyethylene glycol diglycidyl ether = 1: (8-10): (3-4): (0.8-1.2): (0.3-0.5).

[0035] Specifically, the mass ratio range of the reaction raw materials can effectively balance the ratio of polyurethane soft segments to hard segments and the crosslinking density of the konjac glucomannan backbone, ensuring that the composite has both rigid and flexible mechanical properties. If the ratio deviates from this range, it will cause problems such as insufficient or excessive crosslinking, chain segment entanglement or missing dispersion sites, resulting in a decrease in the mechanical properties of the composite and a deterioration in its moldability.

[0036] As one implementation method, the compound antibacterial agent includes propyl gallate and lysozyme.

[0037] Specifically, propyl gallate (PG) is a natural phenolic broad-spectrum antibacterial agent, and lysozyme (LZM) is a natural proteolytic enzyme. The composite antibacterial agent is dispersed in the network structure of the polyurethane substrate layer and is used as a biological composite antibacterial agent. The composite antibacterial agent is uniformly distributed by relying on the dispersion sites of the network structure of the polyurethane substrate layer. After being locked by the network structure, it is released slowly and for a long time. PG breaks the bacterial cell membrane, and LZM enzymatically hydrolyzes it. The combined action of PG and LZM targets pathogenic bacteria, achieving broad-spectrum antibacterial effect without significant migration of the composite antibacterial agent. Specifically, PG first destroys the integrity of the bacterial cell membrane, creating a channel for LZM to penetrate into the bacterial interior. LZM then specifically enzymatically hydrolyzes the peptidoglycan backbone of the bacterial cell wall, causing the bacteria to lose structural support and lyse and die. The two work together to cover pathogenic bacteria such as Escherichia coli, Staphylococcus aureus, and Neisseria gonorrhoeae.

[0038] In one implementation method, the mass ratio of propyl gallate to lysozyme in the compound antibacterial agent is (2.4-6):1.

[0039] Specifically, the mass ratio of propyl gallate and lysozyme in the compound antibacterial agent can be any value within the range of 2.4:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, etc. (2.4-6):1.

[0040] The mass ratio of propyl gallate and lysozyme in the compound antibacterial agent should be controlled within the range of (2.4-6):1. This mass ratio range can ensure sufficient PG to break the cell membrane and efficient enzymatic hydrolysis of LZM. If the mass ratio is less than this range, lysozyme is likely to be excessive, which is easily degraded by human body fluid enzymes. Propyl gallate is relatively insufficient and cannot effectively destroy the cell membrane of pathogenic bacteria, and the antibacterial rate of Neisseria gonorrhoeae will be greatly reduced. If the mass ratio is greater than this range, excessive propyl gallate is likely to cause irritation to human mucous membranes, and excessive PG will agglomerate in the substrate, affecting the uniformity of antibacterial component dispersion.

[0041] As one implementation method, the amount of composite antibacterial agent added is 1.5-2.3% of the total mass of the polyurethane substrate layer.

[0042] Specifically, the amount of composite antibacterial agent added can be any value within the range of 1.5-2.3% of the total mass of the polyurethane substrate layer, such as 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, or 2.3%. Controlling the amount of composite antibacterial agent added within 1.5-2.3% of the total mass of the polyurethane substrate layer effectively balances the antibacterial effect with the overall performance of the polyurethane substrate layer. This ensures sufficient antibacterial components for effective protection without exceeding the dispersion and load-bearing capacity of the substrate's network structure. If the amount added is less than this range, the antibacterial components are insufficient, and the antibacterial rate of the three core pathogenic bacteria is all below 98%, failing to achieve effective antibacterial action. If the amount added is greater than this range, the antibacterial components tend to aggregate beyond the substrate's dispersion sites, forming internal structural defects that lead to decreased mechanical properties. Furthermore, excess antibacterial agent can easily migrate to the human mucous membrane, and excessive migration can pose safety risks.

[0043] As one implementation method, the modified nano zinc oxide is nano zinc oxide modified with KH-560 silane coupling agent.

[0044] Specifically, nano-zinc oxide belongs to inorganic nanoparticles (particle size 30-50 nm). Its surface has densely packed hydroxyl groups and strong polarity, resulting in poor compatibility with the organic phase polyurethane-KGM composite. Nano-zinc oxide easily aggregates with the organic phase polyurethane-KGM composite through hydrogen bonds, making it impossible to disperse uniformly within the organic phase. Therefore, it is necessary to use KH-560 silane coupling agent to modify the surface of nano-zinc oxide. Essentially, this involves introducing organic segments onto the surface of the inorganic nanoparticles through hydrolysis and grafting reactions to eliminate interfacial compatibility differences. During the KH-560 modification process, the KH-560 molecule contains active groups at both ends (one end is a hydrolyzable alkoxy group, and the other end...). The alkoxy group (which is an epoxy group) undergoes a condensation reaction with the hydroxyl groups on the surface of the nano zinc oxide after hydrolysis, forming a stable covalent bond. This allows the epoxy group to be grafted onto the surface of the nano zinc oxide. The epoxy group is an organic functional group that is compatible with the amino groups of the polyurethane chain segment and the hydroxyl groups of KGM, breaking down the interfacial barrier between inorganic particles and organic phases. This enables the nanoparticles (modified nano zinc oxide) to be uniformly dispersed in the polyurethane-KGM composite in the organic phase, avoiding agglomeration and internal defects, and ensuring the stability of the mechanical properties of the substrate. If unmodified nano zinc oxide particles are used, the nanoparticles are prone to agglomeration, leading to stress concentration inside the substrate, a decrease in elongation at break, and powder residue on the surface, which is not conducive to the application of condoms. Meanwhile, the modified nano zinc oxide has epoxy groups introduced on its surface. These groups can undergo weak chemical reactions with the isocyanate groups (-NCO) of the polyurethane prepolymer and the hydroxyl groups of KGM to form chemical bonds, thus fixing the modified nano zinc oxide particles onto the two polymer chain segments. The network structure of the polyurethane-KGM composite can wrap the uniformly dispersed nano zinc oxide particles in the network gaps, further restricting the movement and aggregation of nanoparticles, ensuring the stability of the substrate after molding, reducing the migration of antibacterial components in the condom, and reducing the risk of mucosal irritation.

[0045] As one implementation method, the amount of modified nano zinc oxide added is 1-3% of the total mass of the polyurethane substrate layer.

[0046] Specifically, the amount of modified nano zinc oxide added can be any value within the range of 1% to 3% of the total mass of the polyurethane substrate layer, such as 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, or 3%.

[0047] In one implementation, the thickness of the functional coating is 50-100 nm.

[0048] Specifically, the thickness of the functional coating can be any value within the range of 50-100nm, such as 50nm, 60nm, 70nm, 80nm, 90nm, or 100nm.

[0049] On the other hand, the present invention provides a method for preparing a modified antibacterial polyurethane condom, wherein the chitosan quaternary ammonium salt in the functional coating is connected to the polyurethane substrate layer through covalent bonds formed by biocatalysis, and the covalent bonds are formed by the biocatalytic action of laccase.

[0050] Specifically, laccase is a blue multi-copper oxidase whose core catalytic function is the single-electron oxidation of substrates containing hydroxyl or amino groups to generate highly reactive free radicals or quinone intermediates. In this invention, the active center (copper ion cluster) of laccase can simultaneously oxidize the hydroxyl groups in KGM and the amino groups in HTCC under mild conditions (40-45℃, pH 5.5 acetate-sodium acetate buffer) to generate active intermediates such as carbon free radicals, imine free radicals, or quinone imine intermediates. The highly reactive free radicals or active intermediates formed by oxidation have strong reactivity and can spontaneously react to form stable covalent bonds, thereby stably linking the chitosan quaternary ammonium salt in the functional coating to the polyurethane substrate layer. It is important to emphasize that, unlike traditional chemical grafting (which requires high temperature and strong initiators), the present invention uses laccase because of its specificity and mildness in biocatalysis. Laccase selectively oxidizes only hydroxyl and amino groups, without destroying the ester bonds of polyurethane, the glycosidic bonds of KGM, and the quaternary ammonium groups of HTCC, thus avoiding damage to the substrate structure. Moreover, the process only requires molecular oxygen, and the only byproduct is water, with no toxic residues.

[0051] The preparation of the modified antibacterial polyurethane condom of the present invention includes the following steps (see details). Figure 1 ):

[0052] Step 1: Prepare konjac glucomannan-polyurethane network prepolymer. Prepare a 5-8% (w / w) aqueous solution of modified konjac glucomannan and add polyethylene glycol diglycidyl ether. Pre-crosslink for 30-60 min, then mix with polycaprolactone diol-hexamethylene diisocyanate prepolymer at an NCO / OH molar ratio of 1.3-1.6. Stir at 800-1000 rpm for 60-90 min to form konjac glucomannan-polyurethane network prepolymer.

[0053] Step 2: Prepare the composite antibacterial impregnation solution. Dissolve the konjac glucomannan-polyurethane network prepolymer obtained in Step 1 in a mixed solvent of N,N-dimethylacetamide and ethanol, wherein the volume ratio of N,N-dimethylacetamide to ethanol is 7:(2-4). First, add modified nano zinc oxide and ultrasonically disperse for 20-30 min. Then add propyl gallate-lysozyme composite antibacterial agent and polysorbate-80 with a mass fraction of 0.2-0.5%. Perform ultrasonic dispersion at 200-300W for 40-60 min. Adjust the viscosity of the composite antibacterial impregnation solution to 220-280 mPa·s and let it stand for 30-40 min to remove bubbles.

[0054] Step 3: Impregnation molding and pre-curing. The condom mold is immersed in the composite antibacterial impregnation solution obtained in step 2. The lifting speed is controlled at 5-8 cm / s to form a uniform substrate film. It is then placed in a vacuum environment of 35-40℃ and -0.08 to -0.09 MPa for 40 minutes to pre-cur the film-forming sleeve.

[0055] Step 4: Laccase-catalyzed surface grafting of chitosan quaternary ammonium salt is performed by immersing the film-forming sleeve in a laccase-chitosan quaternary ammonium salt grafting solution prepared with pH 5.5 acetate-sodium acetate buffer. The amount of laccase added is 0.4-0.6% of the mass fraction of the laccase-chitosan quaternary ammonium salt grafting solution, and the amount of chitosan quaternary ammonium salt added is 0.8-1.2% of the mass fraction of the laccase-chitosan quaternary ammonium salt grafting solution. The reaction is carried out at a constant temperature of 40-45℃ for 1.5-2 hours to achieve covalent grafting of chitosan quaternary ammonium salt. The free chitosan quaternary ammonium salt is removed by rinsing with deionized water.

[0056] Step 5: Immerse the grafted film-forming sleeve in a hyaluronic acid composite lubricant, which includes hyaluronic acid and polyethylene glycol 400, with a mass ratio of hyaluronic acid to polyethylene glycol 400 of 1:(1.3-2.0). After lifting coating, place it in a vacuum environment at 45-50℃ for final curing for 30-40 minutes. After demolding and sterilization, the finished modified antibacterial polyurethane condom is obtained.

[0057] In one implementation method, the mass ratio of laccase to chitosan quaternary ammonium salt is (0.4-0.6):(0.8-1.2).

[0058] Specifically, the mass ratio of laccase to chitosan quaternary ammonium salt can be any value within the range of (0.4-0.6):(0.8-1.2), such as 0.4:0.8, 0.4:0.9, 0.4:1, 0.4:1.1, 0.4:1.2, etc.

[0059] The present invention will be further illustrated by the following embodiments.

[0060] In the following examples and comparative examples, all materials used are medical grade. The modified konjac glucomannan (KGM) is modified with glycidyltrimethylammonium chloride and has a molecular weight of 75,000. The polycaprolactone diol (PCL) has a molecular weight of 3,000 and a lysozyme (LZM) activity of ≥2,000 U / mg. The modified nano zinc oxide (ZnO) is modified with KH-560 silane coupling agent (particle size 30-50 nm) and has a laccase activity of ≥1,000 U / mL.

[0061] The mixed solvent was uniformly N,N-dimethylacetamide (DMAc) and ethanol (volume ratio 7:3), and the dispersant was uniformly polysorbate-80 with a mass fraction of 0.2%. The basic ratio of HA to polyethylene glycol 400 (PEG-400) in the hyaluronic acid (HA) composite lubricant was 1:1.5. Example 1

[0062] Raw material ratio (parts by weight):

[0063] The polyurethane substrate layer comprises 1 part by weight of modified konjac glucomannan (KGM), 9 parts by weight of polycaprolactone diol (PCL), 3.5 parts by weight of hexamethylene diisocyanate (HDI), 1.0 part by weight of 1,6-hexanediol and 0.4 parts by weight of polyethylene glycol diglycidyl ether (PEGDE).

[0064] The amount of compound antibacterial agent added is 1.9%. The compound antibacterial agent includes 1.5 parts by weight of propyl gallate (PG) and 0.3 parts by weight of lysozyme (LZM), wherein the mass ratio of PG to LZM is 5:1.

[0065] The amount of modified nano zinc oxide added was 2%;

[0066] The functional coating comprises 0.8 parts by weight of chitosan quaternary ammonium salt (HTCC) and 1.2 parts by weight of hyaluronic acid (HA), with a coating thickness of 75 nm; the mass ratio of HA to polyethylene glycol 400 (PEG-400) in the HA composite lubricant is 1:1.65.

[0067] Preparation method:

[0068] Step 1 uses a 6.5% (w / w) modified konjac glucomannan aqueous solution with an NCO / OH molar ratio of 1.45 and a stirring speed of 900 rpm;

[0069] Step 2: Adjust the viscosity of the impregnation solution to 250 mPa·s;

[0070] The pre-curing conditions for step 3 are 38℃ and -0.085MPa;

[0071] In step 4, the amount of laccase added to the grafting solution was 0.5%, and the amount of HTCC added was 1.0%.

[0072] The final curing temperature in step 5 is 48℃.

[0073] Example 2

[0074] Raw material ratio (parts by weight):

[0075] The polyurethane substrate layer comprises 1 part by weight of modified konjac glucomannan, 8 parts by weight of polycaprolactone diol, 3 parts by weight of hexamethylene diisocyanate, 0.8 parts by weight of 1,6-hexanediol and 0.3 parts by weight of polyethylene glycol diglycidyl ether.

[0076] The amount of compound antibacterial agent added is 1.5%. The compound antibacterial agent includes 1.2 parts by weight of PG and 0.3 parts by weight of LZM, wherein the mass ratio of PG to LZM is 4:1.

[0077] The amount of modified nano zinc oxide added was 1%;

[0078] The functional coating consists of 0.5 parts by weight of HTCC and 1.0 parts by weight of HA, with a coating thickness of 50 nm; the mass ratio of HA to PEG-400 in the HA composite lubricant is 1:1.3.

[0079] Preparation method:

[0080] Step 1 uses a 5% (w / w) modified konjac glucomannan aqueous solution with an NCO / OH molar ratio of 1.3 and a stirring speed of 800 rpm;

[0081] Step 2: Adjust the viscosity of the impregnation solution to 220 mPa·s;

[0082] The pre-curing conditions for step 3 are 35℃ and -0.08MPa;

[0083] In step 4, the amount of laccase added to the grafting solution was 0.4%, and the amount of HTCC added was 0.8%.

[0084] The final curing temperature in step 5 is 45℃.

[0085] Example 3

[0086] Raw material ratio (parts by weight):

[0087] The polyurethane substrate layer comprises 1 part by weight of modified konjac glucomannan, 10 parts by weight of polycaprolactone diol, 4 parts by weight of HDI, 1.2 parts by weight of 1,6-hexanediol and 0.5 parts by weight of PEGDE.

[0088] The amount of compound antibacterial agent added is 2.3%, including 1.8 parts by weight of PG and 0.3 parts by weight of LZM, wherein the mass ratio of PG to LZM is 6:1;

[0089] The amount of modified nano zinc oxide added was 3%;

[0090] The functional coating consists of 1.2 parts by weight of HTCC and 1.5 parts by weight of HA, with a coating thickness of 100 nm; the mass ratio of HA to PEG-400 in the HA composite lubricant is 1:2.0.

[0091] Preparation method:

[0092] Step 1 uses an 8% (w / w) modified konjac glucomannan aqueous solution with an NCO / OH molar ratio of 1.6 and a stirring speed of 1000 rpm;

[0093] Step 2: Adjust the viscosity of the impregnation solution to 280 mPa·s;

[0094] The pre-curing conditions for step 3 are 40℃ and -0.09MPa;

[0095] In step 4, the amount of laccase added to the grafting solution was 0.6%, and the amount of HTCC added was 1.2%.

[0096] The final curing temperature in step 5 is 50℃.

[0097] Example 4

[0098] This embodiment is the same as embodiment 1 in most steps, with the following differences:

[0099] The polyurethane substrate layer comprises 1 part by weight of modified konjac glucomannan, 7 parts by weight of polycaprolactone diol, 2.8 parts by weight of HDI, 0.7 parts by weight of 1,6-hexanediol and 0.2 parts by weight of PEGDE.

[0100] Example 5

[0101] This embodiment is the same as embodiment 1 in most steps, with the following differences:

[0102] The mass ratio of PG to LZM in the compound antibacterial agent is 2:1, and the amount of compound antibacterial agent added is 1.9%. The compound antibacterial agent includes 1.27 parts by weight of PG and 0.63 parts by weight of LZM.

[0103] Comparative Example 1

[0104] The difference between this comparative example and Example 1 is that it uses a single polyurethane substrate, does not contain KGM, and the remaining raw materials and processes are the same as in Example 1.

[0105] Comparative Example 2

[0106] The difference between this comparative example and Example 1 is that plasma grafting process is used instead of laccase-catalyzed grafting process, while the other raw materials and processes are the same as in Example 1.

[0107] Comparative Example 3

[0108] The difference between this comparative example and Example 1 is that the functional coating only includes hyaluronic acid, while the other raw materials and processes are the same as in Example 1.

[0109] Performance testing

[0110] The modified antibacterial polyurethane condoms prepared in the above embodiments and comparative examples were subjected to the following tests. The test sample specifications were 0.05 mm thick and 180 mm long, and the test standards were as follows:

[0111] Mechanical properties: Referring to "HG / T 5456-2018", the dry tensile strength and elongation at break were tested using a WDW-10 universal testing machine at a tensile rate of 500 mm / min.

[0112] Antibacterial rate: Referring to the antibacterial performance test method in the hygiene requirements for disposable sanitary products in GB 15979-2004, and combined with the product characteristics adaptation and adjustment of condoms in HG / T 5456-2018, the 24-hour antibacterial rate of Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 6538), and Neisseria gonorrhoeae (ATCC 49226) was tested in a biosafety level 2 laboratory environment using a 37℃ constant temperature incubator.

[0113] Coating adhesion: Refer to GB / T 9286-1998 and use it as a basis. The test is carried out by using a cross-cut tester (1mm spacing) in combination with pressure-sensitive tape (for attaching samples). In the evaluation standard of coating adhesion, the higher the level, the better the coating adhesion effect.

[0114] The test results are shown in Table 1.

[0115] Table 1

[0116] Group / Performance Dry tensile strength (MPa) Elongation at break (%) Inhibition rate of three pathogenic bacteria (%) Coating adhesion (grade) Example 1 25.6 920 The detection rate for Escherichia coli, Staphylococcus aureus, and Neisseria gonorrhoeae was 99.5%. 4B Example 2 22.8 850 Escherichia coli 99.0%, Staphylococcus aureus 99.2%, Neisseria gonorrhoeae 98.8% 4B Example 3 24.3 890 Escherichia coli, Staphylococcus aureus, and Neisseria gonorrhoeae were all detected at 99.4%. 4B Example 4 19.5 780 Escherichia coli, Staphylococcus aureus, and Neisseria gonorrhoeae were all ≥98.0%. 4B Example 5 24.1 880 Escherichia coli 98.3%, Staphylococcus aureus 98.5%, Neisseria gonorrhoeae 92.1% 4B Comparative Example 1 17.2 620 Escherichia coli, Staphylococcus aureus, and Neisseria gonorrhoeae were all ≤95.0%. 2B Comparative Example 2 23.0 750 Escherichia coli, Staphylococcus aureus, and Neisseria gonorrhoeae were all ≤95.3%. 3B Comparative Example 3 24.5 890 Escherichia coli 94.8%, Staphylococcus aureus 95.1%, Neisseria gonorrhoeae 93.5% 2B

[0117] Based on the test data from the above embodiments and comparative examples, it can be seen that Embodiment 1 of the present invention exhibits the best overall performance, a significant synergistic effect, and balanced mechanical, antibacterial, and lubricating properties. It successfully solves the core technical problems of existing modified antibacterial polyurethane condoms and is suitable for high-demand scenarios. Among the various test indicators of Embodiments 1-3, the dry tensile strength reached 25.6 MPa, the elongation at break was 920%, the antibacterial rate against three pathogenic bacteria was 99.5%, and the coating adhesion was grade 4B; all indicators were qualified. In Example 3, the PEGDE addition reached the upper limit of 0.5 parts, resulting in excessively high crosslinking density. This offset the toughening effect of the polycaprolactone diol soft segments, leading to a slightly lower elongation at break compared to Example 1, but it was still suitable for large-scale production. Example 4 showed a decrease in mechanical properties; although it met basic usage requirements, its performance was significantly lower than Example 1. In Example 5, the antibacterial rate against Neisseria gonorrhoeae decreased significantly. Due to the unique cell membrane structure of Neisseria gonorrhoeae, sufficient PG is required to break the membrane before LZM can exert its enzymatic hydrolytic effect. Excessive degradation of LZM led to insufficient PG, resulting in the most significant decrease in the antibacterial rate against Neisseria gonorrhoeae. This indicates that limiting the proportion of antibacterial agents is crucial for the synergistic antibacterial effect. Among the test indicators of Comparative Examples 1-3, Comparative Example 1, which did not contain KGM, had a dry tensile strength of only 17.2 MPa, an elongation at break of only 620%, an antibacterial rate against all three pathogenic bacteria ≤95.0%, and a coating adhesion grade of only 2B. In Comparative Example 1, the lack of a network structure formed by modified KGM and polyurethane resulted in poor substrate compatibility and insufficient dispersion sites, leading to the aggregation of antibacterial components and weak mechanical support. At the same time, it could not provide stable adhesion sites for the functional coating, making the coating easy to peel off.

[0118] Comparative Example 2 used plasma grafting instead of laccase-catalyzed grafting. Its dry tensile strength was 23.0 MPa, elongation at break was 750%, and antibacterial rate was ≤95.3%. The coating adhesion was grade 3B, but peeled off after 5 uses. The reason is that the plasma grafting process in Comparative Example 2 was too demanding, damaging the integrity of the internal network structure of the substrate, leading to a decline in mechanical properties. Simultaneously, this process could not achieve a stable covalent bond between chitosan quaternary ammonium salt (HTCC) and the substrate, resulting in poor coating adhesion and easy migration of antibacterial components.

[0119] The functional coating of Comparative Example 3 contained only hyaluronic acid and no HTCC. Its mechanical properties were similar to those of Example 1 (dry tensile strength 24.5 MPa, elongation at break 890%), but its antibacterial rate was significantly reduced (both ≤95.1%). The coating adhesion was grade 2B and swelled and peeled off after 3 uses. The reason is that Comparative Example 3 lacked the surface antibacterial enhancement and covalent bond locking effect of HTCC. Relying solely on physical coating with hyaluronic acid (HA), it could not form a surface antibacterial barrier, and because HA lacks covalent bonding ability, it was prone to swelling due to water absorption, leading to coating peeling.

[0120] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A modified antibacterial polyurethane condom, characterized in that, The product includes a polyurethane substrate layer and a functional coating; the polyurethane substrate layer includes a konjac glucomannan-polyurethane composite, a composite antibacterial agent, and modified nano zinc oxide; the functional coating includes chitosan quaternary ammonium salt and hyaluronic acid; wherein the chitosan quaternary ammonium salt in the functional coating is connected to the polyurethane substrate layer through covalent bonds formed by biocatalysis. The reaction raw materials for preparing the konjac glucomannan-polyurethane composite include modified konjac glucomannan, polycaprolactone diol, hexamethylene diisocyanate, 1,6-hexanediol, and polyethylene glycol diglycidyl ether; wherein the modified konjac glucomannan is konjac glucomannan modified with glycidyltrimethylammonium chloride, and the molecular weight of the modified konjac glucomannan is 50,000-80,000.

2. The modified antibacterial polyurethane condom according to claim 1, characterized in that, The mass ratio of the reaction raw materials is modified konjac glucomannan: polycaprolactone diol: hexamethylene diisocyanate: 1,6-hexanediol: polyethylene glycol diglycidyl ether = 1: (8-10): (3-4): (0.8-1.2): (0.3-0.5).

3. The modified antibacterial polyurethane condom according to claim 1, characterized in that, The compound antibacterial agent includes propyl gallate and lysozyme.

4. The modified antibacterial polyurethane condom according to claim 3, characterized in that, The mass ratio of propyl gallate to lysozyme in the composite antibacterial agent is (2.4-6):1, and / or the amount of the composite antibacterial agent added is 1.5-2.3% of the total mass of the polyurethane substrate layer.

5. The modified antibacterial polyurethane condom according to claim 1, characterized in that, The modified nano zinc oxide is nano zinc oxide modified with KH-560 silane coupling agent, and / or the amount of the modified nano zinc oxide added is 1-3% of the total mass of the polyurethane substrate layer.

6. The modified antibacterial polyurethane condom according to claim 1, characterized in that, The mass ratio of the chitosan quaternary ammonium salt to the hyaluronic acid in the functional coating is (0.5-1.2):(1.0-1.5).

7. The modified antibacterial polyurethane condom according to claim 1, characterized in that, The thickness of the functional coating is 50-100 nm.

8. A method for preparing a modified antibacterial polyurethane condom as described in any one of claims 1-7, characterized in that, The chitosan quaternary ammonium salt in the functional coating is connected to the polyurethane substrate layer through covalent bonds formed by biocatalysis, and the covalent bonds are formed by the biocatalytic action of laccase.

9. The preparation method according to claim 8, characterized in that, The mass ratio of laccase to chitosan quaternary ammonium salt is (0.4-0.6):(0.8-1.2).

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