Preparation method of water-based photocuring antibacterial super-hydrophobic coating

Abstract

This invention discloses a method for preparing a waterborne UV-curable antibacterial superhydrophobic coating. Modified polyester-type hydroxyl-terminated vinyl silicone oil and hydroxyl-terminated fluorosilicone oil are introduced into the polyurethane chain as soft segments of the waterborne polyurethane. UV curing increases the crosslinking density of the coating, resulting in higher hardness. Simultaneously, the introduction of a large amount of fluorine and silicon gives the cured coating extremely high hydrophobic properties. The silicon-oxygen structure serves as the main chain of the polyurethane, preventing microphase separation after curing, thus increasing the coating's adhesion, application range, and service life. Quaternary ammonium salts are used to modify nano-TiO2, introducing it into the waterborne resin, resulting in good dispersibility of the nano-TiO2. The coating cured under UV light exhibits even higher hydrophobicity and hardness, while also possessing good antibacterial effects.

Description

Technical Field

[0001] This invention relates to a method for preparing a water-based photocurable antibacterial superhydrophobic coating, belonging to the field of chemical coating production. Background Technology

[0002] UV-curable waterborne coatings possess many advantages of both traditional UV curing and waterborne coating technologies, such as low cost, low viscosity, good application performance, non-toxicity, and non-irritation. Due to the outstanding advantages of UV-curable waterborne resins, their products have been applied in numerous fields.

[0003] There have been numerous reports on the modification of polyurethane with fluorine and silicon. The introduction of fluorine and silicon elements can significantly reduce the surface energy of polyurethane coatings and enhance their oil resistance, weather resistance, and mechanical properties. However, after a period of use, fluorine and silicon elements will undergo microphase separation and gradually "accumulate" on the coating surface. For example, Hong Tan et al. introduced fluorine-containing side chains into polyurethane and studied the phenomenon of fluorine segments migrating to the coating surface, which significantly reduced the service life of the coating. In this invention, polyester-type hydroxyl-terminated vinyl silicone oil and hydroxyl-terminated fluorosilicone oil are prepared and introduced into the polyurethane chain as soft segments of waterborne polyurethane. This not only significantly improves the hydrophobicity of the coating but also increases its density and reduces the occurrence of migration, greatly improving the application range and service life of the coating.

[0004] However, water-based coatings can lead to bacterial invasion during use, and how to inhibit and kill bacteria is currently a key research focus for water-based coatings. One approach is to reduce the surface energy of the resin to create a superhydrophobic coating, reducing adhesion strength to ensure bacteria are removed before forming a biofilm on the surface. The intermolecular forces between microorganisms and the coating cause the adhered organisms to slowly release under low shear stress, ultimately killing the bacteria by causing them to detach. Another approach is to add antibacterial agents to kill bacteria and certain organisms. This invention addresses both aspects, developing a water-based, photocurable antibacterial superhydrophobic coating that significantly improves the hydrophobic properties of the coating, increasing its service life and application range. Summary of the Invention

[0005] This invention prepares polyester-type hydroxyl-terminated vinyl silicone oil and hydroxyl-terminated fluorosilicone oil as soft segments introduced into the polyurethane backbone of waterborne polyurethane. This reduces the decrease in hydrophobicity and coating life caused by the migration of fluorine and silicon elements. Vinyl silicone oil increases the density and hardness of the coating and reduces bacterial invasion, while fluorosilicone oil, as a branch chain, significantly improves the hydrophobicity of the coating, reducing bacterial adhesion and causing organism detachment and bacterial death. Amine-modified nano-titanium dioxide (TiO2) enhances its dispersion performance in waterborne polyurethane coatings, and the introduction of ammonium salts and modified nano-titanium dioxide (TiO2) also improves the antibacterial properties of the coating. This greatly expands the application range of waterborne UV-cured coatings.

[0006] The technical solution adopted in this invention is:

[0007] A method for preparing a water-based, light-curing, antibacterial, superhydrophobic coating includes the following steps:

[0008] (1) Preparation of polyester-type hydroxyl-terminated vinyl silicone oil and hydroxyl-terminated fluorosilicone oil: A certain amount of hydroxyl-terminated vinyl silicone oil, hydroxyl-terminated fluorosilicone oil, polybasic acid (anhydride), catalyst, polymerization inhibitor, solvent and antioxidant were added to a three-necked flask equipped with a stirrer and a thermometer. After stirring, the temperature was raised to a certain temperature and kept at that temperature for a period of time. When the acid value was measured to be lower than 0.1 mg KOH / g, the reaction was stopped. The solvent was removed under negative pressure to obtain polyester-type hydroxyl-terminated vinyl silicone oil and hydroxyl-terminated fluorosilicone oil.

[0009] (2) Preparation of polyurethane: Add the polyester-type hydroxyl-terminated vinyl silicone oil and hydroxyl-terminated fluorosilicone oil synthesized in step (1), catalyst and chain extender to a three-necked flask equipped with a stirrer and thermometer. Heat to 40-50℃ and add diisocyanate dropwise using a constant pressure funnel. The dropwise addition time is controlled at 2-4h. After keeping warm for 2-4h, continue to heat to 90-100℃ and add a certain amount of monomer containing both -OH and -C=C groups. Keep warm for 6-10h. When the isocyanate absorption peak in the infrared absorption peak completely disappears, stop the reaction to obtain polyester-type fluorosilicone modified polyurethane acrylate.

[0010] (3) Modified nano-titanium dioxide (TiO2): A certain amount of nano-titanium dioxide (TiO2), catalyst, solvent and dicarboxylic acid are added to a three-necked flask equipped with a stirrer and thermometer. The temperature is raised to a certain temperature and kept at that temperature until the acid value is <0.1mgKOH / g. Amine is added to neutralize to pH=7-9. The solvent is removed by negative pressure distillation to obtain modified nano-titanium dioxide (TiO2).

[0011] (4) Preparation of waterborne photocurable antibacterial superhydrophobic coating: The polyester-type fluorosilicone modified polyurethane acrylate obtained in step (2) is added to a three-necked flask with a stirrer, and the modified nano titanium dioxide (TiO2) obtained in step (3) is added. The pH is adjusted to 6-9 with amine, and deionized water is added dropwise while stirring at high speed to prepare a waterborne photocurable antibacterial superhydrophobic coating with a solid content of 30-60%.

[0012] As a preferred embodiment, in the above-described method for preparing waterborne photocurable antibacterial superhydrophobic coating, in step (1), the molecular weight of the hydroxyl-terminated vinyl silicone oil is 500-3000, and the molecular weight of the hydroxyl-terminated fluorosilicone oil is 1000-5000; the polyacid (anhydride) is at least one or a mixture of several of the following: 1,6-adipic acid, itaconic acid, citric acid, phthalic anhydride, ethylene oxide, and propylene oxide; the catalyst is at least one or a mixture of several of the following: sulfuric acid, p-toluenesulfonic acid, and methanesulfonic acid aqueous solution; the polymerization inhibitor is at least one or a mixture of several of the following: p-hydroxyanisole, copper chloride, phenothiazine, or hydroquinone; and the antioxidant is... The agent is: hypophosphite aqueous solution; the solvent is: at least one or a mixture of toluene, xylene, petroleum ether, DMF, and n-butanol; the solvent accounts for 15-30% of the total mass, the catalyst accounts for 1-3%, the antioxidant accounts for 0.1-0.5%, and the amount of polymerization inhibitor is 300-1000 ppm of hydroxyl-terminated vinyl silicone oil; the reaction temperature is: 90-130℃, the reaction time is: 10-14h; the negative pressure vacuum degree is: -150--300kpa; the molar ratio of hydroxyl-terminated vinyl silicone oil, hydroxyl-terminated fluorosilicone oil and polybasic acid (anhydride) is: 1:(0.5-2):(1.5-2).

[0013] As a preferred embodiment, in the above-described method for preparing waterborne photocurable antibacterial superhydrophobic coating, the catalyst in step (2) is at least one or a mixture of several of dibutyltin dilaurate, stannous octoate, or organotin compounds; the chain extender is at least one or a mixture of several of dimethylolpropionic acid (DMPA), dimethylolbutyric acid (DMBA), or 3-dimethylamino-1,2-malonic acid (DMAPD); and the diisocyanate is isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), hexamethylene diisocyanate (HDI) trimer, or diphenyl A mixture of at least one or more of methane diisocyanate (MDI) and toluene diisocyanate (TDI); monomers containing both -OH and -C=C groups include: hydroxyethyl acrylate (HEA), hydroxyethyl methacrylate (HEMA), hydroxypropyl acrylate (HPA), hydroxypropyl methacrylate (HPMA), pentaerythritol triacrylate (PETA), and dipentaerythritol pentaacrylate; chain extender accounts for 4-12% of the total mass; the molar ratio of polyester-type hydroxyl-terminated vinyl silicone oil and hydroxyl-terminated fluorosilicone oil to diisocyanate is 1:(2.2-3).

[0014] As a preferred embodiment, in the above-described method for preparing waterborne photocurable antibacterial superhydrophobic coating, the dicarboxylic acid (anhydride) in step (3) is at least one or a mixture of several of 1,6-adipic acid, itaconic acid, and phthalic anhydride; the catalyst is at least one or a mixture of several of sulfuric acid, p-toluenesulfonic acid, and methanesulfonic acid aqueous solution; the solvent is at least one or a mixture of several of toluene, xylene, petroleum ether, DMF, and n-butanol; the solvent accounts for 15-30% of the total mass, and the catalyst accounts for 1-3%; the reaction temperature is 90-130℃, and the negative pressure vacuum degree is -150--300kpa; the mass ratio of nano-titanium dioxide (TiO2) to dicarboxylic acid is (10-20):1; and the amine is at least one or a mixture of several of triethylamine, diethanolamine, ammonia, and aniline.

[0015] As a preferred embodiment, in the above-described method for preparing waterborne photocurable antibacterial superhydrophobic coating, the weight ratio of polyester-type fluorosilicone modified polyurethane acrylate to modified nano-titanium dioxide (TiO2) in step (4) is (5-10):1; the amine is at least one or a mixture of triethylamine, diethanolamine, ammonia (concentration of 20-70%), and aniline; and the stirring speed is 3000-10000 r / min.

[0016] The beneficial effects of this invention are as follows: This invention provides a method for preparing a waterborne UV-curable antibacterial superhydrophobic coating. By introducing fluorine and silicon elements into the polyurethane backbone, the decrease in hydrophobicity and coating lifespan caused by the migration of fluorine and silicon elements is reduced. Vinyl silicone oil increases the density and hardness of the coating, and also reduces bacterial invasion. Fluorosilicone oil, as a side chain, significantly improves the hydrophobicity of the coating, reducing bacterial adhesion and subsequent detachment and death. Amine-modified nano-titanium dioxide (TiO2) enhances its dispersion performance in the waterborne polyurethane coating, and the introduction of ammonium salt-modified nano-titanium dioxide (TiO2) also improves the antibacterial properties of the coating. This expands the application range of the waterborne UV-curable coating and increases its service life. This waterborne coating is currently widely used on the surfaces of plastics, films, pharmaceuticals, and other materials requiring high weather resistance and antifouling properties. Detailed Implementation

[0017] The present invention will be further described below with reference to embodiments, but the embodiments do not constitute a limitation on the scope of protection of the present invention.

[0018] Example 1

[0019] A method for preparing a water-based, light-curing, antibacterial, superhydrophobic coating includes the following steps:

[0020] (1) Preparation of polyester-type hydroxyl-terminated vinyl silicone oil and hydroxyl-terminated fluorosilicone oil: 50g of hydroxyl-terminated vinyl silicone oil with a molecular weight of 500, 100g of hydroxyl-terminated fluorosilicone oil with a molecular weight of 1000, 20g of 1,6-adipic acid, 20g of methanesulfonic acid, 0.25g of p-hydroxyanisole, 384g of xylene and 3g of hypophosphoric acid were added to a three-necked flask equipped with a stirrer and a thermometer. The stirring was started and the temperature was raised to 130℃. The temperature was maintained for 6 hours. When the acid value was measured to be lower than 0.1mgKOH / g, the reaction was stopped. The solvent was removed under negative pressure to obtain polyester-type hydroxyl-terminated vinyl silicone oil and hydroxyl-terminated fluorosilicone oil.

[0021] (2) Preparation of polyurethane: Add the polyester-type hydroxyl-terminated vinyl silicone oil and hydroxyl-terminated fluorosilicone oil synthesized in step (1), 2.5g of dibutyltin dilaurate, and 5g of dimethylolpropionic acid to a three-necked flask equipped with a stirrer and a thermometer. Heat to 40°C and add 90g of isophorone diisocyanate (IPDI) dropwise using a constant pressure funnel. The dropwise addition time is controlled at 2h. After keeping warm for 2h, continue to heat to 90°C and add 25g of hydroxyethyl acrylate (HEA) monomer. Keep warm for 6h. When the isocyanate absorption peak in the infrared absorption peak completely disappears, stop the reaction to obtain polyester-type fluorosilicone modified polyurethane acrylate.

[0022] (3) Modified nano-titanium dioxide (TiO2): Add 200g of nano-titanium dioxide (TiO2), 5g of concentrated sulfuric acid, 50g of xylene, and 10g of 1,6-adipic acid to a three-necked flask equipped with a stirrer and a thermometer. Heat to 130℃ and keep warm until the acid value is <0.1mgKOH / g. Add amine to neutralize to pH=8. Remove the solvent by negative pressure distillation to obtain modified nano-titanium dioxide (TiO2).

[0023] (4) Preparation of waterborne photocurable antibacterial superhydrophobic coating: 200g of polyester-type fluorosilicone modified polyurethane acrylate obtained in step (2) and 25g of modified nano titanium dioxide (TiO2) obtained in step (3) were added to a three-necked flask with a stirrer. The pH was adjusted to 7 with triethylamine and 300g of deionized water was added dropwise while stirring at 7000r / min to prepare a waterborne photocurable antibacterial superhydrophobic coating with a solid content of 36%.

[0024] Take 15g of the prepared waterborne UV-curable antibacterial superhydrophobic coating emulsion and place it in a tetrafluoroethylene tank. Add 2 drops of photoinitiator 1173 and place it in a 45℃ oven for 12 hours. Finally, cure it into a film using a 2kW, 20s / cycle conveyor UV curing machine. Test it according to industry standards. The relevant properties of the coating are shown in Table 1 below.

[0025] Table 1. Coating properties are as follows:

[0026] Testing items Test results Testing standards Stain resistance / grade 0 Q / 321181JPD009-2021 hardness 4H ASTM D 3363-2005 Adhesion 0 ASMD 3359-2002 Antibacterial effect pass European Standard ABGG Abrasion resistance / grade 0 GB / T 17657-2013 .

[0027] Example 2

[0028] A method for preparing a water-based, light-curing, antibacterial, superhydrophobic coating includes the following steps:

[0029] (1) Preparation of polyester-type hydroxyl-terminated vinyl silicone oil and hydroxyl-terminated fluorosilicone oil: 100g of hydroxyl-terminated vinyl silicone oil with a molecular weight of 1000, 100g of hydroxyl-terminated fluorosilicone oil with a molecular weight of 1000, 25g of itaconic acid, 25g of methanesulfonic acid, 0.5g of p-hydroxyanisole, 420g of toluene and 5g of hypophosphoric acid were added to a three-necked flask equipped with a stirrer and a thermometer. The stirring was started and the temperature was raised to 110℃. The temperature was maintained for 8 hours. When the acid value was measured to be lower than 0.1mgKOH / g, the reaction was stopped. The solvent and water were removed under negative pressure to obtain polyester-type hydroxyl-terminated vinyl silicone oil and hydroxyl-terminated fluorosilicone oil.

[0030] (2) Preparation of polyurethane: Add the polyester-type hydroxyl-terminated vinyl silicone oil and hydroxyl-terminated fluorosilicone oil synthesized in step (1), 3g of dibutyltin dilaurate, and 8g of dimethylolbutyric acid to a three-necked flask equipped with a stirrer and a thermometer. Heat to 40°C and add 110g of isophorone diisocyanate (IPDI) dropwise using a constant pressure funnel. The dropwise addition time is controlled at 2.5h. After keeping warm for 3h, continue to heat to 90°C and add 35g of hydroxyethyl methacrylate (HEMA) monomer. Keep warm for 8h until the isocyanate absorption peak in the infrared absorption peak completely disappears. Stop the reaction to obtain polyester-type fluorosilicone modified polyurethane acrylate.

[0031] (3) Modified nano-titanium dioxide (TiO2): Add 200g of nano-titanium dioxide (TiO2), 5g of methanesulfonic acid, 50g of xylene, and 15g of 1,6-adipic acid to a three-necked flask equipped with a stirrer and a thermometer. Heat to 130℃ and keep warm until the acid value is <0.1mgKOH / g. Add amine to neutralize to pH=7. Remove the solvent by negative pressure distillation to obtain modified nano-titanium dioxide (TiO2).

[0032] (4) Preparation of waterborne photocurable antibacterial superhydrophobic coating: 200g of polyester-type fluorosilicone modified polyurethane acrylate obtained in step (2) and 30g of modified nano titanium dioxide (TiO2) obtained in step (3) were added to a three-necked flask with a stirrer. The pH was adjusted to 8 with triethylamine and 300g of deionized water was added dropwise while stirring at 4000r / min to prepare a waterborne photocurable antibacterial superhydrophobic coating with a solid content of 42%.

[0033] Take 15g of the prepared waterborne UV-curable antibacterial superhydrophobic coating emulsion and place it in a tetrafluoroethylene tank. Add 2 drops of photoinitiator 1173 and place it in a 45℃ oven for 12 hours. Finally, cure it into a film using a 2kW, 20s / cycle conveyor UV curing machine. Test it according to industry standards. The relevant properties of the coating are shown in Table 2 below.

[0034] Table 2. Coating properties are as follows:

[0035] Testing items Test results Testing standards Stain resistance / grade 0 Q / 321181JPD009-2021 hardness 5H ASTM D 3363-2005 Adhesion 0 ASMD 3359-2002 Antibacterial effect pass European Standard ABGG Abrasion resistance / grade 0 GB / T 17657-2013 .

Claims

1. A method for preparing a water-based, photocurable, antibacterial, superhydrophobic coating, characterized in that, Includes the following steps: (1) Preparation of polyester-type hydroxyl-terminated vinyl silicone oil and polyester-type hydroxyl-terminated fluorosilicone oil: A certain amount of hydroxyl-terminated vinyl silicone oil, hydroxyl-terminated fluorosilicone oil, polybasic acid (anhydride), catalyst, polymerization inhibitor, solvent, and antioxidant were added to a three-necked flask equipped with a stirrer and a thermometer. The stirring was started, the temperature was raised to a certain temperature, and the temperature was maintained for a period of time. When the acid value was measured to be lower than 0.1 mg KOH / g, the reaction was stopped. The solvent was removed under negative pressure to obtain polyester-type hydroxyl-terminated vinyl silicone oil and polyester-type hydroxyl-terminated fluorosilicone oil. (2) Preparation of polyester-type fluorosilicone modified polyurethane acrylate: Add polyester-type hydroxyl-terminated vinyl silicone oil and polyester-type hydroxyl-terminated fluorosilicone oil, catalyst and chain extender synthesized in step (1) to a three-necked flask equipped with a stirrer and thermometer. Heat to 40~50℃, add diisocyanate dropwise using a constant pressure funnel, and control the dropwise addition time to 2~4h. After keeping warm for 2~4h, continue to heat to 90~100℃, and add a certain amount of monomer containing both -OH and -C=C groups. Keep warm for 6~10h until the isocyanate absorption peak in the infrared absorption peak completely disappears. Stop the reaction to obtain polyester-type fluorosilicone modified polyurethane acrylate. The monomers containing both -OH and -C=C groups are: hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, pentaerythritol triacrylate, and dipentaerythritol pentaacrylate. (3) Modified nano titanium dioxide: Add a certain amount of nano titanium dioxide, catalyst, solvent and dicarboxylic acid to a three-necked flask equipped with a stirrer and thermometer, heat to a certain temperature, keep warm until the acid value is <0.1mgKOH / g, add amine to neutralize to pH=7~9, remove solvent by negative pressure distillation to obtain modified nano titanium dioxide; (4) Preparation of waterborne photocurable antibacterial superhydrophobic coating: Add the polyester-type fluorosilicone modified polyurethane acrylate obtained in step (2) to a three-necked flask with a stirrer, add the modified nano titanium dioxide obtained in step (3), adjust the pH to 6~9 with amine, and add deionized water dropwise while stirring at high speed to prepare a water-based photocurable antibacterial superhydrophobic coating.

2. The preparation method of the waterborne photocurable antibacterial superhydrophobic coating as described in claim 1, characterized in that, In step (1), the molecular weight of hydroxyl-terminated vinyl silicone oil is 500~3000, and the molecular weight of hydroxyl-terminated fluorosilicone oil is 1000~5000. The polybasic acid (anhydride) is at least one or a mixture of several of the following: 1,6-adipic acid, itaconic acid, citric acid, and phthalic anhydride; The catalyst is: at least one or a mixture of several of the following: sulfuric acid, p-toluenesulfonic acid, and aqueous solution of methanesulfonic acid; The polymerization inhibitor is at least one or a mixture of several of p-hydroxyanisole, copper chloride, phenothiazine, or hydroquinone; The antioxidant is: hypophosphite aqueous solution; The solvent is: at least one or a mixture of several of the following: toluene, xylene, petroleum ether, DMF, and n-butanol; The solvent accounts for 15-30% of the total mass, the catalyst accounts for 1-3%, the antioxidant accounts for 0.1-0.5%, and the amount of polymerization inhibitor is 300-1000 ppm of hydroxyl-terminated vinyl silicone oil; the reaction temperature is 90-130℃, the reaction time is 10-14 h; the negative pressure vacuum degree is -150--300 kPa; the molar ratio of hydroxyl-terminated vinyl silicone oil, hydroxyl-terminated fluorosilicone oil and polybasic acid (anhydride) is 1:0.5-2:1.5-2.

3. The preparation method of the waterborne photocurable antibacterial superhydrophobic coating as described in claim 1, characterized in that, The catalyst in step (2) is at least one of dibutyltin dilaurate or stannous octoate, or a mixture thereof; The chain extender is at least one of dimethylolpropionic acid or dimethylolbutyric acid or a mixture thereof; The diisocyanate is at least one or a mixture of several of the following: isophorone diisocyanate, hexamethylene diisocyanate, hexamethylene diisocyanate trimer, diphenylmethane diisocyanate, and toluene diisocyanate; The chain extender accounts for 4-12% of the total mass; the molar ratio of polyester-type hydroxyl-terminated vinyl silicone oil and polyester-type hydroxyl-terminated fluorosilicone oil to diisocyanate is 1:2.2-3.

4. The preparation method of the waterborne photocurable antibacterial superhydrophobic coating as described in claim 1, characterized in that, The dicarboxylic acid in step (3) is at least one or a mixture of several of 1,6-adipic acid and itaconic acid; The catalyst is: at least one or a mixture of several of the following: sulfuric acid, p-toluenesulfonic acid, and aqueous solution of methanesulfonic acid; The solvent is: at least one or a mixture of several of the following: toluene, xylene, petroleum ether, DMF, and n-butanol; The amine is: at least one or a mixture of several of the following: triethylamine, diethanolamine, ammonia, and aniline; The solvent accounts for 15-30% of the total mass, the catalyst accounts for 1-3%, and the mass ratio of nano-titanium dioxide to dicarboxylic acid is 10-2:1; the reaction temperature is 90-130℃, and the negative pressure vacuum degree is -150--300kpa.

5. The preparation method of the waterborne photocurable antibacterial superhydrophobic coating as described in claim 1, characterized in that, In step (4), the weight ratio of polyester-type fluorosilicone modified polyurethane acrylate to modified nano-titanium dioxide is 5~10:1; The amine is at least one or a mixture of triethylamine, diethanolamine, ammonia water with a concentration of 20-70%, and aniline; the stirring speed of the reaction is 3000-10000 r / min.