Antibacterial polyurethane waterproof coating and preparation method thereof

Abstract

The invention provides an antibacterial polyurethane waterproof coating and a preparation method thereof, and relates to the technical field of waterproof coatings. Comprising 70 to 80 wt% of a polyurethane matrix, 10 to 20 wt% of a filler, 3 to 10 wt% of an antibacterial agent, 2 to 6 wt% of a plasticizer, 0.3 to 1 wt% of an antifoaming agent, 0.3 to 0.8 wt% of a leveling agent, 1 to 4 wt% of a water repellent agent, 0.4 to 2 wt% of an antioxidant and 0.5 to 2 wt% of a dispersant, and the polyurethane matrix is obtained by modifying a polyurethane prepolymer with a peroxy modified monomer; the antibacterial agent is a porous carrier loaded with essential oil. A polyurethane prepolymer is modified by a peroxide modified monomer to obtain a peroxide-containing polyurethane matrix, and the peroxide-containing polyurethane matrix and natural essential oil cooperate to achieve dual antibacterial effects and are cooperatively compounded with a filler, a dispersing agent, a plasticizer, a defoaming agent, a flatting agent, a water repellent agent and an antioxidant at the same time; the obtained antibacterial polyurethane waterproof coating has a good antibacterial effect and also has good waterproofness, mechanical properties and adhesive force.

Description

Technical Field

[0001] The present invention relates to the technical field of waterproof coatings, and in particular to an antibacterial polyurethane waterproof coating and a preparation method thereof. Background Art

[0002] Polyurethane coatings are synthetic resin coatings made from isocyanate-containing prepolymers formed through the addition polymerization of isocyanates and polyethers, along with catalysts, anhydrous additives, and anhydrous fillers. These coatings exhibit excellent wear resistance, flexibility, resilience, and gloss, combining decorative and protective properties. They are widely used in tunnels, subways, high-speed rail systems, roofs, and kitchens and bathrooms, demonstrating their excellent application value. Antimicrobial and waterproof coatings are specialized coatings that combine antimicrobial and waterproof properties to provide protection and hygiene for various surfaces.

[0003] The antimicrobial agents added to existing polyurethane coatings primarily include nanosilver, nanozinc oxide, hydroquinone compounds, essential oils, and quaternary ammonium salts. Nanosilver antimicrobial agents are expensive, and the long-term release of silver ions can be potentially toxic to the environment and the human body. Nanozinc oxide requires ultraviolet (UV) activation to release its antimicrobial active substances, which significantly reduces its effectiveness in dark environments. It also lacks compatibility with the coating substrate and is prone to sedimentation or loss of effectiveness over long-term use. Hydroquinone compounds pose risks to the environment and health. Some quaternary ammonium salt antimicrobial agents are difficult to degrade, can contaminate water bodies, and are prone to migration or dissolution from the coating, affecting long-term antimicrobial performance. Essential oil antimicrobial agents, while environmentally friendly, are volatile and difficult to retain in the coating over the long term. Therefore, there is an urgent need to develop a new antimicrobial polyurethane waterproof coating. Summary of the Invention

[0004] In order to solve the above problems, the present invention provides an antibacterial polyurethane waterproof coating. A polyurethane matrix containing peroxy groups is obtained by modifying a polyurethane prepolymer with a peroxy group-modified monomer. The peroxy group can generate reactive oxygen species (ROS), destroying microbial cell membranes and biological molecules (such as proteins and DNA), thereby achieving high-efficiency and broad-spectrum antibacterial properties. The added antibacterial agent is a porous carrier loaded with essential oils. The porous carrier can limit the diffusion of essential oils through adsorption, delay the volatilization of essential oils and prolong the release, thereby achieving synergistic dual antibacterial effects of natural essential oils (contact sterilization) and peroxy groups (oxidative sterilization). At the same time, the antibacterial polyurethane waterproof coating is synergistically compounded with fillers, dispersants, plasticizers, defoaming agents, leveling agents, hydrophobic agents and antioxidants, so that the antibacterial polyurethane waterproof coating has good antibacterial effect and good waterproofness, mechanical properties and adhesion.

[0005] A first aspect of the present invention provides an antibacterial polyurethane waterproof coating, which comprises, by mass fraction, 70-80 wt% of a polyurethane matrix, 10-20 wt% of a filler, 3-10 wt% of an antibacterial agent, 2-6 wt% of a plasticizer, 0.3-1 wt% of a defoaming agent, 0.3-0.8 wt% of a leveling agent, 1-4 wt% of a hydrophobic agent, 0.4-2 wt% of an antioxidant, and 0.5-2 wt% of a dispersant.

[0006] The polyurethane matrix is ​​obtained by modifying a polyurethane prepolymer with a peroxide-modified monomer; and the antibacterial agent is essential oil loaded on a porous carrier.

[0007] Optionally, the antimicrobial polyurethane waterproof coating comprises: a polyurethane matrix (73-76 wt%), a filler (13-17 wt%), an antimicrobial agent (5-7 wt%), a plasticizer (4-5 wt%), a defoamer (0.5-0.7 wt%), a leveling agent (0.4-0.6 wt%), a hydrophobic agent (2-3 wt%), an antioxidant (0.7-1 wt%), and a dispersant (0.8-1.5 wt%). Furthermore, in the antimicrobial polyurethane waterproof coating of this application, the addition amounts of each raw material are controlled to ensure basic film-forming properties, mechanical strength, and adhesion by controlling the amount of polyurethane matrix added. The antimicrobial agent addition amount is controlled at 3-10 wt% to avoid poor antimicrobial effect if too low, and agglomeration and decreased mechanical properties if too high. The filler addition amount is controlled at 10-20 wt% to avoid increased viscosity and decreased mechanical properties if too high. The plasticizer addition amount is controlled at 2-6 wt% to allow it to intercalate into the polyurethane soft segment, improving flexibility. Excessive addition reduces tensile strength and may even cause the coating to become sticky. The defoamer dosage should be controlled between 0.3-1wt% to avoid excessive addition, which can cause oily spots on the coating surface or affect adhesion. Antioxidants at 0.4-2wt% can inhibit the oxidation of essential oils and the premature decomposition of peroxide groups, extending the coating's service life. However, excessive addition may interfere with the polyurethane curing reaction or reduce antimicrobial activity. The hydrophobic agent dosage should be controlled between 1-4wt%. Excessive addition may cause coating embrittlement or reduce compatibility with the substrate. Dispersants at 0.5-2wt% prevent particle agglomeration through electrostatic / steric stabilization.

[0008] Optionally, the preparation process of the polyurethane matrix includes the following steps:

[0009] The polyol and isocyanate are mixed and reacted at a first temperature, and then a catalyst is added to obtain a polyurethane prepolymer; then a peroxy-modified monomer is added and reacted at a second temperature, and finally a chain extender is added and reacted at a third temperature to obtain a polyurethane matrix.

[0010] Optionally, the peroxy-modified monomer accounts for 5wt%-15wt% of the polyurethane prepolymer. Optionally, the peroxy-modified monomer accounts for 8wt%-12wt% of the polyurethane prepolymer. If the peroxy-modified monomer addition level is too low, the peroxy group content is insufficient, the ROS release is low, and the antibacterial effect is weak. Excessive peroxy-modified monomer content may cause excessive crosslinking of the prepolymer, resulting in increased coating brittleness.

[0011] Alternatively, the polyol may be one or more of polyether polyol, polyester polyol, polycarbonate polyol or vegetable oil-based polyol. For example, the polyether polyol may be polyoxypropylene glycol (PPG) or polytetramethylene glycol (PTMG). The polyester polyol may be polybutylene adipate or polycaprolactone polyol. The polycarbonate polyol may be polycarbonate diol. The vegetable oil-based polyol may be castor oil polyol or soybean oil polyol. However, the present invention is not limited thereto, and those skilled in the art may select suitable polyol according to circumstances.

[0012] Optionally, the isocyanate is one or more of isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), toluene diisocyanate or xylylenediisocyanate (XDI).

[0013] Optionally, the peroxide-modified monomer is one of tert-butyl peroxymaleic anhydride (TBPMA), dicumyl peroxide (DCP), benzoyl peroxide (BPO) or lauroyl peroxide (LPO).

[0014] Optionally, the catalyst is an organotin catalyst, an organobismuth catalyst, an amine catalyst, or a metal-free catalyst. For example, the organotin catalyst may be dibutyltin dilaurate. The organobismuth catalyst may be one of bismuth neodecanoate, bismuth isooctanoate, bismuth laurate, bismuth thioglycolate, bismuth thiopropionate, isopropoxy bismuth, or bismuth ethoxylate. The amine catalyst may be triethylenediamine. The metal-free catalyst may be 1,5,7-triazabicyclo[4.4.0]dec-5-ene. However, the present invention is not limited thereto, and those skilled in the art may select a suitable catalyst according to the circumstances.

[0015] Optionally, the chain extender is one of 1,4-butanediol, ethylene glycol (EG), diethylene glycol (DEG), diethyltoluenediamine, 3,3'-dichloro-4,4'-diaminodiphenylmethane or trimethylolpropane (TMP).

[0016] Optionally, the first temperature is 75-85°C. Optionally, the first temperature is 78-82°C.

[0017] Optionally, the second temperature is 55-65°C. Optionally, the second temperature is 58-62°C.

[0018] Optionally, the third temperature is 65-75°C. Optionally, the third temperature is 68-72°C.

[0019] Optionally, the preparation method of the antibacterial agent comprises the following steps:

[0020] A. Essential oil is added to a polyethylene glycol-polypropylene glycol block copolymer (PEO-PPO-PEO) and mixed at a fourth temperature to form an emulsion. The polyethylene glycol-polypropylene glycol block copolymer is used to modify the essential oil to be amphiphilic. The PPO segments can encapsulate the essential oil molecules, while the PEO segments provide hydrophilicity, improving compatibility with the polyurethane matrix.

[0021] B. Disperse the porous carrier in a solvent, add the emulsion from step A, perform ultrasonic treatment, and vacuum dry to obtain the porous carrier-loaded essential oil. The mesoporous structure of the porous carrier can adsorb the essential oil through capillary action, inhibiting volatilization, prolonging release, and improving thermal stability.

[0022] Optionally, the HLB of the polyethylene glycol-polypropylene glycol block copolymer is 8-12. The present application selects a polyethylene glycol-polypropylene glycol block copolymer with an HLB of 8-12. The growth of the PPO chain segments can effectively encapsulate the essential oil molecules to form stable micelles or emulsions. The ether bond (-O-) of PEO can form hydrogen bonds with the polar groups in the polyurethane, thereby enhancing interfacial bonding. The hydrophobicity of PPO is more compatible with the polyurethane backbone and can reduce phase separation. Excessively long PEO chains may cause the coating to be too hydrophilic and reduce its water resistance. The present application takes into account both compatibility and water resistance by controlling the HLB value.

[0023] Optionally, the mass ratio of the polyethylene glycol-polypropylene glycol block copolymer to the essential oil is 1:(8-12).

[0024] Optionally, the mass ratio of essential oil to porous carrier is 1:(2-4).

[0025] Optionally, the plasticizer is one of dioctyl phthalate (DOP), diisononyl phthalate (DINP), epoxidized soybean oil (ESO), tributyl citrate (TBC) or acetyl tributyl citrate (ATBC).

[0026] Optionally, the filler is one or more of kaolin, heavy calcium carbonate, titanium dioxide, talc, or illite powder. For example, kaolin may be 2500-3500 mesh, heavy calcium carbonate may be 2000-3000 mesh, and illite powder may be 1500-2500 mesh.

[0027] Optionally, the defoaming agent is polydimethylsiloxane or polyether modified silicone oil.

[0028] Optionally, the leveling agent is a silicone leveling agent, an acrylate leveling agent, or a fluorine-modified leveling agent. For example, the silicone leveling agent may be BYK-306, the acrylate leveling agent may be BYK-354, and the fluorine-modified leveling agent may be BYK-306.

[0029] Optionally, the antioxidant is one of vitamin E or rosemary extract.

[0030] Optionally, the hydrophobic agent is heptadecafluorodecyltriethoxysilane or polydimethylsiloxane.

[0031] Optionally, the dispersant is selected from one or more of polyacrylamide, sodium lauryl sulfate, ethyl acetate, propylene glycol methyl ether acetate, butyl acetate, xylene or trimethylbenzene.

[0032] Optionally, the essential oil is one or more of tea tree essential oil, cinnamon essential oil, citronella essential oil, patchouli essential oil, chamomile essential oil, coriander essential oil, clove essential oil, thyme essential oil, and rosemary essential oil.

[0033] Optionally, the porous carrier is one or more of mesoporous silica, activated carbon or cellulose nanocrystals.

[0034] Optionally, the porous carrier has a pore size of not less than 2 nm and a specific surface area of ​​200-1000 m 2 / g.

[0035] Optionally, mesoporous silica is obtained by amino modification, specifically: the dried mesoporous SiO2 is dispersed in anhydrous toluene, 3-aminopropyltriethoxysilane (APTES) is added, and the mixture is reacted at 75-85°C under nitrogen protection, and then centrifuged, washed, and dried in sequence to obtain amino mesoporous silica. In the mesoporous silica that has been amino-modified, the amino group forms hydrogen bonds with the hydroxyl or carboxyl group in the essential oil, thereby increasing the adsorption capacity and delaying the release of the essential oil through hydrogen bonding or electrostatic effects. The amino group has better compatibility with the polar groups of the polyurethane matrix, which can reduce agglomeration and improve dispersibility.

[0036] Optionally, the activated carbon is treated with hydrophobicity. Specifically, the activated carbon is immersed in an acid solution, then immersed in an ethanol solution containing 0.5-1.5 wt% heptafluorodecyltriethoxysilane and ultrasonically treated. The activated carbon is then heated and cured at 110-130°C, followed by washing and drying to obtain the hydrophobically modified activated carbon. Furthermore, the fluorocarbon chains in the hydrophobically modified activated carbon enhance water resistance, reduce water penetration, and prevent the premature release or hydrolysis of essential oils due to water contact.

[0037] Optionally, the cellulose nanocrystals are acetylated. Specifically, the cellulose nanocrystals are dispersed in glacial acetic acid to form a uniform suspension. Acetic anhydride and concentrated sulfuric acid are then added and reacted at 50-70°C. The suspension is then centrifuged, washed, and dried to obtain acetylated cellulose nanocrystals. Acetylation of the cellulose nanocrystals improves their compatibility with the polyurethane matrix and enhances their dispersibility.

[0038] Optionally, the antibacterial polyurethane waterproof coating further includes a pigment. The type of pigment is not particularly limited, and any suitable pigment (for example, carbon black, iron red or other colored organic pigments and combinations thereof, etc.) can be used in the antibacterial polyurethane waterproof coating.

[0039] A second aspect of the present invention provides a method for preparing an antibacterial polyurethane waterproof coating, the preparation method comprising the following steps:

[0040] S1: Mix the polyurethane matrix with the plasticizer and dispersant at a certain temperature to obtain a primary mixture; mixing the polyurethane matrix with the plasticizer first can reduce the viscosity of the system and lay the foundation for the subsequent dispersion of the antibacterial agent and filler.

[0041] S2: adding antimicrobial agent and filler to the primary mixture and mixing;

[0042] S3: Then, a hydrophobic agent, an antioxidant, a defoaming agent, and a leveling agent are added in sequence and mixed to obtain an antibacterial polyurethane waterproof coating.

[0043] Optionally, the certain temperature in step S1 is 50-70°C.

[0044] Optionally, the above raw materials are subjected to vacuum drying and dehydration treatment before being added.

[0045] Compared with the prior art, the present invention achieves at least one of the following beneficial effects:

[0046] (1) The antibacterial polyurethane waterproof coating of the present invention is obtained by modifying a polyurethane prepolymer with a peroxy group-modified monomer to obtain a polyurethane matrix containing peroxy groups. The peroxy groups can generate reactive oxygen species (ROS) to destroy microbial cell membranes and biological molecules (such as proteins and DNA), thereby achieving high-efficiency and broad-spectrum antibacterial properties. The added antibacterial agent is a porous carrier loaded with essential oils. The porous carrier can limit the diffusion of essential oils through adsorption, delay the volatilization of essential oils and prolong the release of essential oils, thereby achieving synergistic dual antibacterial properties of natural essential oils (contact sterilization) and peroxy groups (oxidative sterilization). At the same time, it is synergistically compounded with fillers, dispersants, plasticizers, defoaming agents, leveling agents, hydrophobic agents and antioxidants, so that the antibacterial polyurethane waterproof coating has good antibacterial effect and good waterproofness, mechanical properties and adhesion.

[0047] (2) The present invention uses polyethylene glycol-polypropylene glycol block copolymer to perform amphiphilic modification on essential oils. The PPO segment can wrap the essential oil molecules, and the PEO segment can provide hydrophilicity to the outside, thereby improving the compatibility with the polyurethane matrix. DETAILED DESCRIPTION

[0048] In order to more clearly illustrate the overall concept of the present invention, a detailed description is given below in an illustrative manner in conjunction with the specification.

[0049] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0050] Example 1

[0051] In an exemplary embodiment of the present invention, the antibacterial polyurethane waterproof coating includes, by mass fraction, 76 wt% of a polyurethane matrix, 10 wt% of a filler, 6 wt% of an antibacterial agent, 4 wt% of a plasticizer, 0.5 wt% of a defoaming agent, 0.5 wt% of a leveling agent, 2 wt% of a hydrophobic agent, 0.5 wt% of an antioxidant, and 0.5 wt% of a dispersant.

[0052] The preparation method comprises the following steps:

[0053] S01: Polytetramethylene glycol (PTMG) and isophorone diisocyanate (IPDI) were mixed in a molar ratio of 1:2 and reacted at 75°C for 3 hours. A catalyst, dibutyltin dilaurate (0.2 wt %), was added to produce a polyurethane prepolymer. Then, 5 wt % tert-butyl peroxide maleic anhydride was added and reacted at 55°C for 2 hours. Finally, 6 wt % 1,4-butanediol was added and reacted at 65°C for 2 hours to produce the polyurethane matrix.

[0054] S02: Mesoporous silica with a pore size of 10 nm and a specific surface area of ​​500 m 2 / g, dispersed in anhydrous ethanol, added tea tree essential oil and cinnamon essential oil (mass ratio 4:1), the total mass of essential oil to mesoporous silica mass ratio was 1:2, ultrasonic treatment for 30min, and dried at 60℃ for 15h to obtain a porous carrier loaded with essential oil.

[0055] S1: The polyurethane matrix was mixed with the plasticizer dioctyl phthalate and the dispersant polyacrylamide, and stirred at 60°C for 20 min at low speed (500 rpm).

[0056] S2: Add the porous carrier loaded with essential oil and 3000 mesh kaolin as filler, and shear at high speed (5000 rpm) for 1 hour.

[0057] S3: Then, a hydrophobic agent heptafluorodecyl triethoxysilane, an antioxidant vitamin E, a defoaming agent polydimethylsiloxane, and a leveling agent BYK-306 were added in sequence and stirred at a medium speed (1000 rpm) for 20 minutes to obtain an antibacterial polyurethane waterproof coating.

[0058] Example 2

[0059] In an exemplary embodiment of the present invention, the antibacterial polyurethane waterproof coating includes, by mass fraction: 80wt% of polyurethane matrix, 10wt% of filler, 3wt% of antibacterial agent, 2wt% of plasticizer, 0.3wt% of defoaming agent, 0.3wt% of leveling agent, 2wt% of hydrophobic agent, 1wt% of antioxidant, and 1.4wt% of dispersant.

[0060] The preparation method comprises the following steps:

[0061] S01: Polyoxypropylene glycol (PPG) and hexamethylene diisocyanate (HDI) were mixed in a molar ratio of 1:2 and reacted at 85°C for 2 hours. A catalyst (0.2 wt% dibutyltin dilaurate) was added to produce a polyurethane prepolymer. Next, 10 wt% dicumyl peroxide was added and reacted at 65°C for 2 hours. Finally, 6 wt% ethylene glycol was added and reacted at 75°C for 2 hours to produce a polyurethane matrix.

[0062] S02: Cellulose nanocrystals with a pore size of 20 nm and a specific surface area of ​​300 m 2 / g, dispersed in glacial acetic acid, added tea tree essential oil and clove essential oil (mass ratio 3:1), the total mass of essential oil to cellulose nanocrystal mass ratio was 1:4, ultrasonic treatment for 30min, and dried at 60℃ for 15h to obtain a porous carrier loaded with essential oil.

[0063] S1: The polyurethane matrix was mixed with the plasticizer diisononyl phthalate and the dispersant ethyl acetate, and stirred at 60°C for 20 min at low speed (500 rpm).

[0064] S2: Add the porous carrier loaded with essential oil and filler 2000 mesh illite powder, and shear at high speed (5000 rpm) for 1 hour.

[0065] S3: Then, a hydrophobic agent polydimethylsiloxane, an antioxidant vitamin E, a defoaming agent polydimethylsiloxane, and a leveling agent BYK-354 were added in sequence and stirred at a medium speed (1000 rpm) for 20 minutes to obtain an antibacterial polyurethane waterproof coating.

[0066] Example 3

[0067] In an exemplary embodiment of the present invention, the antibacterial polyurethane waterproof coating includes, by mass fraction: 73wt% of polyurethane matrix, 13wt% of filler, 5wt% of antibacterial agent, 4wt% of plasticizer, 0.6wt% of defoaming agent, 0.5wt% of leveling agent, 2wt% of hydrophobic agent, 0.9wt% of antioxidant, and 1wt% of dispersant.

[0068] The preparation method comprises the following steps:

[0069] S01: Polycarbonate diol and isophorone diisocyanate (IPDI) were mixed in a molar ratio of 1:2 and reacted at 80°C for 2 hours. 0.2 wt% of bismuth laurate was added as a catalyst to produce a polyurethane prepolymer. Next, 8 wt% of benzoyl peroxide was added and reacted at 60°C for 2 hours. Finally, 8 wt% of ethylene glycol was added and reacted at 70°C for 2 hours to produce a polyurethane matrix.

[0070] S02: Cellulose nanocrystals with a pore size of 20 nm and a specific surface area of ​​300 m 2 / g, dispersed in glacial acetic acid, and sonicated for 30 minutes to form a uniform suspension. Acetic anhydride and a small amount of concentrated sulfuric acid (1 wt%) were added, with a mass ratio of cellulose nanocrystals to acetic anhydride of 1:5. The mixture was stirred at 60°C for 3 hours, centrifuged, washed with deionized water, and freeze-dried to obtain acetylated cellulose nanocrystals.

[0071] S03: Acetylated cellulose nanocrystals were added to tea tree essential oil and clove essential oil (mass ratio 3:1), with the total mass of essential oil to the mass ratio of acetylated cellulose nanocrystals being 1:3. The mixture was ultrasonically treated for 30 minutes and dried at 60°C for 15 hours to obtain a porous carrier loaded with essential oil.

[0072] S1: The polyurethane matrix was mixed with the plasticizer epoxy soybean oil and the dispersant sodium lauryl sulfate, and stirred at 60°C for 20 min at low speed (500 rpm).

[0073] S2: Add the porous carrier loaded with essential oil and 3000 mesh kaolin as filler, and shear at high speed (5000 rpm) for 1 hour.

[0074] S3: Then, a hydrophobic agent heptafluorodecyl triethoxysilane, an antioxidant vitamin E, a defoaming agent polydimethylsiloxane, and a leveling agent BYK-354 were added in sequence and stirred at a medium speed (1000 rpm) for 20 minutes to obtain an antibacterial polyurethane waterproof coating.

[0075] Example 4

[0076] In an exemplary embodiment of the present invention, the antibacterial polyurethane waterproof coating includes, by mass fraction: 75wt% polyurethane matrix, 11wt% filler, 5wt% antibacterial agent, 4wt% plasticizer, 0.6wt% defoamer, 0.5wt% leveling agent, 2wt% hydrophobic agent, 0.9wt% antioxidant, and 1wt% dispersant.

[0077] The preparation method comprises the following steps:

[0078] S01: Polytetramethylene glycol (PTMG) and isophorone diisocyanate (IPDI) were mixed in a molar ratio of 1:2 and reacted at 70°C for 3 hours. A catalyst, dibutyltin dilaurate (0.2 wt %), was added to produce a polyurethane prepolymer. Then, 5 wt % tert-butyl peroxide maleic anhydride was added and reacted at 50°C for 2 hours. Finally, 6 wt % 1,4-butanediol was added and reacted at 60°C for 2 hours to produce the polyurethane matrix.

[0079] S02: Mesoporous silica with a pore size of 10 nm and a specific surface area of ​​500 m 2 / g, and vacuum-dried at 120°C for 5 hours to remove surface moisture. The dried mesoporous silica was dispersed in anhydrous toluene, and 3-aminopropyltriethoxysilane was added. Under nitrogen, the mixture was stirred at 80°C for 10 hours to hydrolyze the 3-aminopropyltriethoxysilane and graft it onto the SiO2 surface via silanol condensation. The product was centrifuged, washed, and dried to obtain amino-modified mesoporous silica. The mass ratio of 3-aminopropyltriethoxysilane to mesoporous silica was 8:1.

[0080] S03: Disperse the amino-modified mesoporous silica in anhydrous ethanol, add tea tree essential oil and cinnamon essential oil (mass ratio 4:1), the mass ratio of the total essential oil to the amino-modified mesoporous silica is 1:3, ultrasonically treat for 30 minutes, and dry at 60°C for 15 hours to obtain a porous carrier loaded with essential oil.

[0081] S1: The polyurethane matrix was mixed with the plasticizer epoxy soybean oil and the dispersant sodium lauryl sulfate, and stirred at 60°C for 20 min at low speed (500 rpm).

[0082] S2: Add the porous carrier loaded with essential oil and 3000 mesh kaolin as filler, and shear at high speed (5000 rpm) for 1 hour.

[0083] S3: Then, a hydrophobic agent heptafluorodecyl triethoxysilane, an antioxidant vitamin E, a defoaming agent polydimethylsiloxane, and a leveling agent BYK-306 were added in sequence and stirred at a medium speed (1000 rpm) for 20 minutes to obtain an antibacterial polyurethane waterproof coating.

[0084] Example 5

[0085] In an exemplary embodiment of the present invention, the antibacterial polyurethane waterproof coating includes, by mass fraction: 75wt% polyurethane matrix, 11wt% filler, 5wt% antibacterial agent, 4wt% plasticizer, 0.6wt% defoamer, 0.5wt% leveling agent, 2wt% hydrophobic agent, 0.9wt% antioxidant, and 1wt% dispersant.

[0086] The preparation method comprises the following steps:

[0087] S01: Polytetramethylene glycol (PTMG) and isophorone diisocyanate (IPDI) were mixed in a molar ratio of 1:2 and reacted at 70°C for 3 hours. A catalyst, dibutyltin dilaurate (0.2 wt %), was added to produce a polyurethane prepolymer. Then, 5 wt % tert-butyl peroxide maleic anhydride was added and reacted at 50°C for 2 hours. Finally, 6 wt % 1,4-butanediol was added and reacted at 60°C for 2 hours to produce the polyurethane matrix.

[0088] S02: Mesoporous silica with a pore size of 10 nm and a specific surface area of ​​500 m 2 / g, and vacuum-dried at 120°C for 5 hours to remove surface moisture. The dried mesoporous silica was dispersed in anhydrous toluene, and 3-aminopropyltriethoxysilane was added. Under nitrogen, the mixture was stirred at 80°C for 10 hours to hydrolyze the 3-aminopropyltriethoxysilane and graft it onto the SiO2 surface via silanol condensation. The product was centrifuged, washed, and dried to obtain amino-modified mesoporous silica. The mass ratio of 3-aminopropyltriethoxysilane to mesoporous silica was 8:1.

[0089] S03: Tea tree essential oil and cinnamon essential oil were mixed in a mass ratio of 4:1, and polyethylene glycol-polypropylene glycol block copolymer (10% by mass of the total essential oil) was added. The mixture was stirred at 40°C for 3 hours to form a stable emulsion. The polyethylene glycol-polypropylene glycol block copolymer had an HLB of 10.

[0090] S04: Disperse the amino-modified mesoporous silica in anhydrous ethanol, add a stabilizing emulsion, and adjust the mass ratio of the total essential oil to the amino-modified mesoporous silica to be 1:3. Ultrasonic treatment is performed for 30 minutes, and the mixture is dried at 60°C for 15 hours to obtain a porous carrier loaded with essential oil.

[0091] S1: The polyurethane matrix was mixed with the plasticizer epoxy soybean oil and the dispersant sodium lauryl sulfate, and stirred at 60°C for 20 min at low speed (500 rpm).

[0092] S2: Add the porous carrier loaded with essential oil and 3000 mesh kaolin as filler, and shear at high speed (5000 rpm) for 1 hour.

[0093] S3: Then, a hydrophobic agent heptafluorodecyl triethoxysilane, an antioxidant vitamin E, a defoaming agent polydimethylsiloxane, and a leveling agent BYK-306 were added in sequence and stirred at a medium speed (1000 rpm) for 20 minutes to obtain an antibacterial polyurethane waterproof coating.

[0094] Example 6

[0095] In an exemplary embodiment of the present invention, the antibacterial polyurethane waterproof coating includes, by mass fraction: 75wt% polyurethane matrix, 11wt% filler, 5wt% antibacterial agent, 4wt% plasticizer, 0.6wt% defoamer, 0.5wt% leveling agent, 2wt% hydrophobic agent, 0.9wt% antioxidant, and 1wt% dispersant.

[0096] The preparation method comprises the following steps:

[0097] S01: Polycarbonate diol and isophorone diisocyanate (IPDI) were mixed in a molar ratio of 1:2 and reacted at 80°C for 2 hours. Bismuth laurate (0.2 wt%) was added as a catalyst to produce a polyurethane prepolymer. Dicumyl peroxide (8 wt%) was then added and reacted at 60°C for 2 hours. Finally, ethylene glycol (8 wt%) was added and reacted at 70°C for 2 hours to produce a polyurethane matrix.

[0098] S02: Cellulose nanocrystals with a pore size of 20 nm and a specific surface area of ​​300 m 2 / g, dispersed in glacial acetic acid, and sonicated for 30 minutes to form a uniform suspension. Acetic anhydride and a small amount of concentrated sulfuric acid (1 wt%) were added, with a mass ratio of cellulose nanocrystals to acetic anhydride of 1:5. The mixture was stirred at 60°C for 3 hours, centrifuged, washed with deionized water, and freeze-dried to obtain acetylated cellulose nanocrystals.

[0099] S03: Tea tree oil and clove oil were mixed in a mass ratio of 3:1, and polyethylene glycol-polypropylene glycol block copolymer (8% by mass of the essential oil) was added. The mixture was stirred magnetically at 40°C for 2 hours to form a stable emulsion. The polyethylene glycol-polypropylene glycol block copolymer had an HLB of 12.

[0100] S04: Acetylated cellulose nanocrystals were dispersed in anhydrous glacial acetic acid, and a stabilizing emulsion was added. The mass ratio of the total essential oil to the acetylated cellulose nanocrystals was 1:3. The mixture was ultrasonically treated for 30 minutes and dried at 60°C for 15 hours to obtain a porous carrier loaded with essential oil.

[0101] S1: The polyurethane matrix was mixed with the plasticizer epoxy soybean oil and the dispersant sodium lauryl sulfate, and stirred at 60°C for 20 min at low speed (500 rpm).

[0102] S2: Add the porous carrier loaded with essential oil and 3000 mesh kaolin as filler, and shear at high speed (5000 rpm) for 1 hour.

[0103] S3: Then, a hydrophobic agent heptafluorodecyl triethoxysilane, an antioxidant vitamin E, a defoaming agent polydimethylsiloxane, and a leveling agent BYK-354 were added in sequence and stirred at a medium speed (1000 rpm) for 20 minutes to obtain an antibacterial polyurethane waterproof coating.

[0104] Example 7

[0105] In an exemplary embodiment of the present invention, the antibacterial polyurethane waterproof coating includes, by mass fraction: 75wt% polyurethane matrix, 11wt% filler, 5wt% antibacterial agent, 4wt% plasticizer, 0.6wt% defoamer, 0.5wt% leveling agent, 2wt% hydrophobic agent, 0.9wt% antioxidant, and 1wt% dispersant.

[0106] The preparation method comprises the following steps:

[0107] S01: Polycarbonate diol and xylylenediisocyanate (XDI) were mixed in a molar ratio of 1:2 and reacted at 80°C for 2 hours. A catalyst (0.2 wt% dibutyltin dilaurate) was added to produce a polyurethane prepolymer. Next, 8 wt% dicumyl peroxide was added and reacted at 60°C for 2 hours. Finally, 8 wt% 1,4-butanediol was added and reacted at 70°C for 2 hours to produce a polyurethane matrix.

[0108] S02: activated carbon with a pore size of 5 nm and a specific surface area of ​​800 m 2 / g, immersed in a hydrochloric acid solution (6mol / L), stirred at 80°C for 4 hours to remove surface impurities and metal ions, washed with water until neutral, and then dried. The acid-washed activated carbon was then immersed in an ethanol solution containing 1% heptafluorodecyltriethoxysilane, ultrasonically treated for 30 minutes, heat-cured at 120°C for 2 hours, then washed with ethanol and vacuum-dried at 60°C to obtain hydrophobic modified activated carbon.

[0109] S03: Cinnamon and chamomile essential oils were mixed in a mass ratio of 1:2, and polyethylene glycol-polypropylene glycol block copolymer (8% by mass of the essential oils) was added. The mixture was stirred magnetically at 40°C for 2 hours to form a stable emulsion. The polyethylene glycol-polypropylene glycol block copolymer had an HLB of 8.

[0110] S04: Disperse the hydrophobically modified activated carbon in anhydrous ethanol, add a stabilizing emulsion, and adjust the mass ratio of the total essential oil to the hydrophobically modified activated carbon to be 1:3. Ultrasonic treatment is performed for 30 minutes, and the mixture is dried at 60°C for 15 hours to obtain a porous carrier loaded with essential oil.

[0111] S1: The polyurethane matrix was mixed with the plasticizer epoxy soybean oil and the dispersant sodium lauryl sulfate, and stirred at 60°C for 20 min at low speed (500 rpm).

[0112] S2: Add the porous carrier loaded with essential oil and 3000 mesh kaolin as filler, and shear at high speed (5000 rpm) for 1 hour.

[0113] S3: Then, a hydrophobic agent heptafluorodecyl triethoxysilane, an antioxidant vitamin E, a defoaming agent polydimethylsiloxane, and a leveling agent BYK-354 were added in sequence and stirred at a medium speed (1000 rpm) for 20 minutes to obtain an antibacterial polyurethane waterproof coating.

[0114] Example 8

[0115] Based on Example 1, the main difference is that the added amount of the peroxide-modified monomer is 20 wt%.

[0116] Comparative Example 1

[0117] Based on Example 1, the main difference is that the polyurethane matrix is ​​60wt%.

[0118] Comparative Example 2

[0119] Based on Example 1, the main difference is that the antibacterial agent is essential oil, and the essential oil is not loaded on a porous carrier.

[0120] Comparative Example 3

[0121] Based on Example 1, the main difference is that the polyurethane matrix is ​​not modified with a peroxide-modified monomer.

[0122] Comparative Example 4

[0123] Based on Example 1, the main difference is that the antibacterial agent is 20wt%.

[0124] Test Case

[0125] The antibacterial polyurethane waterproof coatings prepared in the examples and comparative examples were subjected to a brushing test with a thickness of 1 mm to form a coating film. The coating film was tested for mechanical properties, waterproofness and antibacterial properties, and the results are shown in Table 1.

[0126] Mechanical properties: ASTM D412 (dumbbell specimen, tensile rate 500 mm / min) was used.

[0127] Water resistance: Water absorption test, using ASTM D570 (24-hour immersion, mass change rate).

[0128] Antibacterial properties: According to ISO 22196 (Test for antibacterial properties of plastic surfaces): the inhibition rate against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) is tested after 7 days of sustained release.

[0129] Table 1

[0130]

[0131] As shown in Table 1, the antibacterial polyurethane waterproof coating prepared by the present invention has a tensile strength of not less than 15 MPa, an elongation at break of 250-600%, a water absorption rate of not more than 5%, and an antibacterial rate of not less than 40%. The antibacterial polyurethane waterproof coating has good antibacterial effect while having good waterproofness, mechanical properties and adhesion.

[0132] The foregoing is merely an embodiment of the present invention and is not intended to limit the present invention. It will be apparent to those skilled in the art that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are intended to be included within the scope of the claims of the present invention.

Claims

1. An antibacterial polyurethane waterproof coating, characterized in that: The antibacterial polyurethane waterproof coating comprises, by mass fraction, 70-80 wt% of a polyurethane matrix, 10-20 wt% of a filler, 3-10 wt% of an antibacterial agent, 2-6 wt% of a plasticizer, 0.3-1 wt% of a defoaming agent, 0.3-0.8 wt% of a leveling agent, 1-4 wt% of a hydrophobic agent, 0.4-2 wt% of an antioxidant, and 0.5-2 wt% of a dispersant. The polyurethane matrix is ​​obtained by modifying a polyurethane prepolymer with a peroxide-modified monomer; and the antibacterial agent is essential oil loaded on a porous carrier.

2. The antibacterial polyurethane waterproof coating according to claim 1, characterized in that: The preparation process of the polyurethane matrix includes the following steps: The polyol and isocyanate are mixed and reacted at a first temperature, and then a catalyst is added to obtain a polyurethane prepolymer; then a peroxy-modified monomer is added and reacted at a second temperature, and finally a chain extender is added and reacted at a third temperature to obtain a polyurethane matrix.

3. The antibacterial polyurethane waterproof coating according to claim 2, characterized in that: The polyol is one or more of polyether polyol, polyester polyol, polycarbonate polyol or vegetable oil-based polyol; and / or the isocyanate is one or more of isophorone diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, toluene diisocyanate or xylylenediisocyanate; and / or the peroxide-modified monomer is one of tert-butyl peroxide maleic anhydride, dicumyl peroxide, benzoyl peroxide or lauroyl peroxide; and / or the catalyst is one of an organotin catalyst, an organobismuth catalyst, an amine catalyst or a metal-free catalyst; and / or the chain extender is one of 1,4-butanediol, ethylene glycol, diethylene glycol, diethyltoluenediamine, 3,3'-dichloro-4,4'-diaminodiphenylmethane or trimethylolpropane.

4. The antibacterial polyurethane waterproof coating according to claim 2, characterized in that: The first temperature is 75-85°C; and / or the second temperature is 55-65°C; and / or the third temperature is 65-75°C.

5. The antibacterial polyurethane waterproof coating according to claim 1, characterized in that: The preparation method of the antibacterial agent comprises the following steps: A. adding the essential oil to the polyethylene glycol-polypropylene glycol block copolymer and mixing at a fourth temperature to form an emulsion; B. Dispersing the porous carrier in a solvent, adding the emulsion in step A, performing ultrasonic treatment, and vacuum drying to obtain the porous carrier loaded with essential oil.

6. The antibacterial polyurethane waterproof coating according to claim 5, characterized in that: The HLB of polyethylene glycol-polypropylene glycol block copolymer is 8-12.

7. The antibacterial polyurethane waterproof coating according to claim 5, characterized in that: The mass ratio of polyethylene glycol-polypropylene glycol block copolymer to essential oil is 1:(8-12); And / or the mass ratio of essential oil to porous carrier is 1:(2-4).

8. The antibacterial polyurethane waterproof coating according to claim 1, characterized in that: The plasticizer is one of dioctyl phthalate, diisononyl phthalate, epoxidized soybean oil, tributyl citrate or acetyl tributyl citrate; and / or the filler is one or more of kaolin, heavy calcium carbonate, titanium dioxide, talc or illite powder; and / or the defoaming agent is polydimethylsiloxane or polyether modified silicone oil; and / or the leveling agent is one of an organic silicone leveling agent, an acrylate leveling agent or a fluorine-modified leveling agent; and / or the antioxidant is one of vitamin E or rosemary extract; and / or the hydrophobic agent is heptadecafluorodecyltriethoxysilane or polydimethylsiloxane; and / or the dispersant is selected from one or more of polyacrylamide, sodium lauryl sulfate, ethyl acetate, propylene glycol methyl ether acetate, butyl acetate, xylene or trimethylbenzene; and / or the essential oil is one or more of tea tree essential oil, cinnamon essential oil, citronella essential oil, patchouli essential oil, chamomile essential oil, coriander essential oil, clove essential oil, thyme essential oil, and rosemary essential oil; And / or the porous carrier is one or more of mesoporous silica, activated carbon or cellulose nanocrystals.

9. The antibacterial polyurethane waterproof coating according to claim 5, characterized in that: Mesoporous silica is modified by amino treatment; and / or the activated carbon is hydrophobized; and / or the cellulose nanocrystals are acetylated.

10. A method for preparing the antibacterial polyurethane waterproof coating according to any one of claims 1 to 9, characterized in that: The preparation method comprises the following steps: S1: mixing the polyurethane matrix with the plasticizer and the dispersant at a certain temperature to obtain a primary mixture; S2: adding antimicrobial agent and filler to the primary mixture and mixing; S3: Then, a hydrophobic agent, an antioxidant, a defoaming agent, and a leveling agent are added in sequence and mixed to obtain an antibacterial polyurethane waterproof coating.

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