Antibacterial waterborne photocurable coating, method for preparing and use thereof

Abstract

The application provides an antibacterial water-based photocuring coating as well as a preparation method and application thereof. 、 Polyether modifier, photoinitiator, photosensitive sensitizer, defoaming agent, leveling agent, antibacterial agent and water, wherein the substrate comprises epoxy resin, the antibacterial agent comprises 2,3-epoxypropyl trimethyl ammonium chloride and silver element loaded nanosilica. In the technical scheme, the polyether modified epoxy resin, the silver element loaded nanosilica and the 2,3-epoxypropyl trimethyl ammonium chloride are added into the epoxy resin based coating to prepare the antibacterial coating with high emulsion stability and low sedimentation rate. In particular, the antibacterial synergism and durability of the silver element loaded nanosilica and the 2,3-epoxypropyl trimethyl ammonium chloride are realized, and the antibacterial effect of the coating is significantly improved.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and in particular to an antibacterial waterborne UV-curable coating, its preparation method, and its application. Background Technology

[0002] Antibacterial coatings have wide applications in daily life, especially in medical institutions, the catering industry, and public places. The antibacterial function of these coatings mainly comes from the antibacterial agents added to them. Currently commonly used antibacterial agents include silver-based antibacterial agents, which use nano-silver or silica-coated nano-silver as the antibacterial material. The antibacterial agent is prepared by dispersing nano-silver or silica-coated nano-silver in a water-ethanol solution (volume ratio 80-85:15-20), and then adding the antibacterial agent to water-based antibacterial coatings as a dispersion. However, simple silver-based antibacterial agents have a single composition, are prone to precipitation, easily impart color, have poor long-lasting antibacterial effects, and are costly to rely solely on silver antibacterial agents. Summary of the Invention

[0003] The main objective of this invention is to propose an antibacterial waterborne UV-curable coating, its preparation method, and its application, aiming to solve the problems of easy discoloration and coating emulsion stability when using silver-based antibacterial agents alone.

[0004] To achieve the above objectives, this invention proposes the synergistic effect of silver-based antibacterial agents and 2,3-epoxypropyltrimethylammonium chloride: on the one hand, it achieves a high antibacterial effect while significantly reducing the amount of silver-based antibacterial agents used; on the other hand, the addition of 2,3-epoxypropyltrimethylammonium chloride can simultaneously improve the stability of the emulsion.

[0005] The method employed in this invention is as follows: Developing an antibacterial waterborne UV-curable coating, comprising the following raw material components by weight:

[0006] 35-45 parts epoxy resin;

[0007] 15-20 parts of polyether modifier;

[0008] 1-3 parts of 2,3-epoxypropyltrimethylammonium chloride;

[0009] 2-3 parts of photoinitiator;

[0010] 0-2 parts of photosensitizer;

[0011] Defoamer 0.1-1.0 parts;

[0012] Leveling agent 0.1 to 1.0 parts;

[0013] 0.01–0.1 parts of silica-supported silver nanoparticles; and,

[0014] 25-45 parts water.

[0015] Optionally, in the silver-loaded silica sol, silver particles are loaded on the surface or within the pores of the silica sol.

[0016] Optionally, the silver particles have a particle size of 20–60 nm.

[0017] Optionally, the epoxy value of the epoxy resin is 0.44 to 0.51, and the epoxy resin includes bisphenol A glycidyl ether epoxy resin E51.

[0018] The present invention also proposes a method for preparing the antibacterial waterborne UV-curable coating, comprising the following steps:

[0019] S10, Synthetic polyether modifier:

[0020] Epoxy resin is mixed with polyethylene glycol with a molecular weight of 4000-8000 and stirred at 55-65°C for 20-30 minutes to obtain mixture 1;

[0021] Add 5 parts by mass of potassium persulfate solution (the mass percentage concentration of potassium persulfate solution is 0.8 wt.%) to mixture 1, and stir at 160°C for 360-390 minutes. After cooling, the polyether modifier is obtained.

[0022] S20, Synthesis of silver-loaded silica sol:

[0023] Add 10 parts by mass of silver nitrate aqueous solution (silver nitrate aqueous solution concentration is 0.05mol / L) to 10 parts by mass of alkaline silica sol (alkaline silica sol concentration is 30%), stir and mix to obtain mixture 2;

[0024] While stirring, 30 parts by mass of glucose aqueous solution (0.01 mol / L glucose aqueous solution) were added to mixture 2 to obtain silicon-supported silver sol;

[0025] The silica-supported silver sol was freeze-dried to obtain silica-supported silver nanoparticles.

[0026] S30, Preparation of UV-curable coatings:

[0027] Epoxy resin and polyether modifier are mixed to obtain mixture 3;

[0028] A 2% (w / w) aqueous solution of 2,3-epoxypropyltrimethylammonium chloride was added to mixture 3. The mixture was stirred at 60–65°C for 60–80 minutes to obtain mixture 4.

[0029] At room temperature, according to the proportions described in claim 1, add defoamer, leveling agent, photoinitiator, photosensitizer, and loaded silver silica gel to mixture 4 and mix evenly to obtain an antibacterial waterborne photocurable coating.

[0030] The present invention also proposes the application of the aforementioned antibacterial waterborne UV-curable coating, or the antibacterial waterborne UV-curable coating prepared by the aforementioned preparation method, in the preparation of antibacterial paint films, the application comprising the following steps:

[0031] S40, Preparation of antibacterial coating film:

[0032] The antibacterial waterborne UV-curable coating obtained in step S30 is used to prepare a wet film by roller coating, dip coating, spray coating, etc. After drying or baking, it is cured by irradiation at a wavelength of 100W 365-405nm for 10-30s in a UV curing oven to obtain the antibacterial coating film.

[0033] The technical solution provided by this invention achieves synergistic and durable antibacterial properties between silver-loaded nano-silica and 2,3-epoxypropyltrimethylammonium chloride, significantly improving the antibacterial effect of the coating. Furthermore, due to the addition of 2,3-epoxypropyltrimethylammonium chloride to the coating, increased emulsion stability was observed within the scope of this invention. Therefore, 2,3-epoxypropyltrimethylammonium chloride has been found to possess excellent synergistic antibacterial and emulsion stabilizing effects within the scope of this invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them.

[0035] It should be noted that, unless specific conditions are specified in the embodiments, conventional conditions or conditions recommended by the manufacturer should be followed. Reagents or instruments whose manufacturers are not specified are all commercially available products. Furthermore, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. In addition, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, such a combination should be considered non-existent and not within the scope of protection claimed by this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention.

[0036] Currently, commonly used antibacterial agents include silver-based antibacterial agents. These agents use nano-silver or silica-coated nano-silver as the antibacterial material. The antibacterial agent is prepared by dispersing nano-silver or silica-coated nano-silver in a water-ethanol solution (volume ratio 80-85:15-20), and then adding the antibacterial agent to water-based antibacterial coatings as a dispersion. However, simple silver-based antibacterial agents have a single composition, are prone to precipitation, easily become discolored due to the silver content, have poor long-lasting antibacterial effects, and are costly to rely solely on silver antibacterial agents.

[0037] In view of this, the present invention proposes an antibacterial waterborne photocurable coating, comprising the following raw material components by weight: 35-45 parts epoxy resin; 15-20 parts polyether modifier; 1-3 parts 2,3-epoxypropyltrimethylammonium chloride; 2-3 parts photoinitiator; 0-2 parts photosensitizer; 0.1-1.0 parts defoamer; 0.1-1.0 parts leveling agent; 0.01-0.1 parts silica gel-supported nano-silver; and 25-45 parts water.

[0038] In some embodiments of the present invention, the photoinitiator comprises triphenylhexafluorophosphate thioonium salt, specifically PAS12 photosensitizer from Shenzhen Youyang Technology Co., Ltd.; the sensitizer is Foamaster NXZ aqueous defoamer manufactured by BASF AG; and the leveling agent is HR-6022 manufactured by Dongguan Hongrui Co., Ltd. It is understood that in this embodiment, the photoinitiator, the sensitizer, and the leveling agent can be replaced with conventional materials well known to those skilled in the art, and the specific components are not limited herein.

[0039] The technical solution provided by this invention involves adding polyether-modified epoxy resin, silver-loaded silica gel, and 2,3-epoxypropyltrimethylammonium chloride to an epoxy resin-based coating to obtain an antibacterial coating with high emulsion stability and low sedimentation rate. Specifically, this invention achieves synergistic and durable antibacterial properties between silver-loaded nano-silica gel and 2,3-epoxypropyltrimethylammonium chloride, significantly improving the antibacterial effect of the coating. The antibacterial coating prepared according to the above-mentioned proportions of raw materials exhibits good stability, water resistance after curing, initial antibacterial performance, and long-term antibacterial performance.

[0040] Furthermore, in the silver-loaded silica sol, silver particles are loaded on the surface of the silica sol; and / or, both the surface of the silver-loaded silica sol and the interior of the particles contain silver particles.

[0041] By loading silver particles onto the surface or interior of silica sol, the dispersibility of silver particles in coatings can be improved, thereby improving the antibacterial properties and stability of the coatings.

[0042] Furthermore, the silver particles have a particle size of 20–60 nm.

[0043] By setting the particle size of silver particles to 20–60 nm, the incomplete coordination of surface atoms in nanoscale silver particles increases the number of active sites on the surface, giving them the basic conditions to act as antibacterial agents, thus enabling nanoscale silver particles to achieve broad-spectrum antibacterial effects. If the particle size of silver particles is greater than 60 nm, the antibacterial effect deteriorates significantly, and they are more prone to sedimentation and color development. If the particle size of silver particles is less than 20 nm, the antibacterial effect of silver particles is not further enhanced, while the production cost increases significantly.

[0044] Furthermore, the epoxy value of the epoxy resin is 0.44 to 0.51, and the epoxy resin includes bisphenol A glycidyl ether epoxy resin E51.

[0045] By setting the epoxy value of the epoxy resin to 0.40–0.54, the required amount of photoinitiator and photosensitizer can be controlled, avoiding the reduction of coating stability caused by excessive or insufficient addition of photoinitiator or photosensitizer.

[0046] The present invention also proposes a method for preparing the antibacterial waterborne UV-curable coating, comprising the following steps:

[0047] S10, Synthetic polyether modifier:

[0048] Epoxy resin is mixed with polyethylene glycol with a molecular weight of 4000-8000 and stirred at 55-65°C for 20-30 minutes to obtain mixture 1;

[0049] Add 5 parts by mass of potassium persulfate solution (the mass percentage concentration of potassium persulfate solution is 0.8 wt.%) to mixture 1, and stir at 160°C for 360-390 minutes. After cooling, the polyether modifier is obtained.

[0050] S20, Synthesis of silver-loaded silica sol:

[0051] Add 10 parts by mass of silver nitrate aqueous solution (silver nitrate aqueous solution concentration is 0.05mol / L) to 10 parts by mass of alkaline silica sol (alkaline silica sol concentration is 30%), stir and mix to obtain mixture 2;

[0052] While stirring, 30 parts by mass of glucose aqueous solution (0.01 mol / L glucose aqueous solution) were added to mixture 2 to obtain silicon-supported silver sol;

[0053] The silica-supported silver sol was freeze-dried to obtain silica-supported silver nanoparticles.

[0054] S30, Preparation of UV-curable coatings:

[0055] Epoxy resin and polyether modifier are mixed to obtain mixture 3;

[0056] A 2% (w / w) aqueous solution of 2,3-epoxypropyltrimethylammonium chloride was added to mixture 3. The mixture was stirred at 60–65°C for 60–80 minutes to obtain mixture 4.

[0057] At room temperature, according to the proportions described in claim 1, add defoamer, leveling agent, photoinitiator, photosensitizer, and loaded silver silica gel to mixture 4 and mix evenly to obtain an antibacterial waterborne photocurable coating.

[0058] Nanoscale silver particles were prepared by freeze-drying a mixture of silver nitrate aqueous solution and alkaline silica sol, allowing the silver nitrate in the solution to slowly precipitate and be loaded onto the silica sol. By loading the silver nanoparticles onto silica gel with freshly prepared silica gel, the aggregation of the silica gel-loaded silver nanoparticles during storage was reduced, improving the dispersibility of the silver nanoparticles, thereby enhancing the stability and antibacterial effect of the prepared antibacterial coating.

[0059] The present invention also proposes the application of the aforementioned antibacterial waterborne UV-curable coating, or the antibacterial waterborne UV-curable coating prepared by the above preparation method, in the preparation of antibacterial paint films, the application comprising the following steps:

[0060] S40, Preparation of antibacterial coating film:

[0061] The antibacterial waterborne UV-curable coating obtained in step S30 is used to prepare a wet film by roller coating, dip coating, spray coating, etc. After drying or baking, it is cured by irradiation at a wavelength of 100W 365-405nm for 10-30s in a UV curing oven to obtain the antibacterial coating film.

[0062] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0063] Example 1

[0064] This embodiment also provides a method for preparing an antibacterial waterborne UV-curable coating, comprising the following steps:

[0065] (1) Weigh 9.85g of epoxy resin and 50.0g of polyethylene glycol into a three-necked flask, heat to 60°C, and stir at 150rpm for 20 minutes to obtain mixture 1;

[0066] (2) Under stirring, 5g of potassium persulfate solution (the mass percentage concentration of potassium persulfate solution is 0.8wt.%) is added dropwise to mixture 1 at a uniform rate, the temperature is gradually increased to 160℃, and stirring is maintained for 360 minutes to obtain polyether modifier;

[0067] (3) Add 10g of 0.05mol / L silver nitrate aqueous solution to 10g of alkaline silica sol and stir until homogeneous to obtain mixture 2;

[0068] (4) Under stirring at 150 rpm, a glucose aqueous solution with a concentration of 0.01 mol / L was added dropwise to mixture 2 to prepare silver-supported silica sol.

[0069] (5) The silicon-supported silver sol was freeze-dried to obtain silica-supported silver nanoparticles.

[0070] (6) Take 35g of epoxy resin and 15g of polyether modifier and place them in a three-necked flask. Heat to 65°C and stir at 450rpm for 10 minutes to obtain mixture 3.

[0071] (7) Take 1g of 2,3-epoxypropyltrimethylammonium chloride and dissolve it in 46.75g of deionized water to obtain an aqueous solution of 2,3-epoxypropyltrimethylammonium chloride.

[0072] (8) Under stirring at 850 rpm, an aqueous solution of 2,3-epoxypropyltrimethylammonium chloride was added dropwise to mixture 3 at a rate of 10 parts by mass per minute, and kept warm for 60 minutes to obtain mixture 4;

[0073] (9) After cooling mixture 4 to room temperature, add 0.1g defoamer, 0.1g leveling agent, 1g photoinitiator, 1g photosensitizer and 0.05g silica-supported nano silver to obtain antibacterial modified photocurable coating.

[0074] (10) Place the fifth mixture on a 70×150mm tinplate scraper and light-cur it to obtain an antibacterial layer.

[0075] Example 2

[0076] This embodiment also provides a method for preparing an antibacterial waterborne UV-curable coating, which is similar to the preparation method provided in Example 1, except that:

[0077] In step (7), 2g of 2,3-epoxypropyltrimethylammonium chloride is dissolved in 44.77g of deionized water to obtain an aqueous solution of 2,3-epoxypropyltrimethylammonium chloride.

[0078] In step (9), the mass of the photoinitiator is 2g and the mass of the silver-loaded silica sol is 0.03g.

[0079] Example 3

[0080] This embodiment is similar to the preparation method provided in Example 1, the difference being:

[0081] In step (7), 3g of 2,3-epoxypropyltrimethylammonium chloride was dissolved in 44.77g of deionized water to obtain an aqueous solution of 2,3-epoxypropyltrimethylammonium chloride.

[0082] In step (9), the mass of the photoinitiator is 2g and the mass of the silica-supported silver nanoparticles is 0.03g.

[0083] Example 4

[0084] This embodiment is similar to the preparation method provided in Example 1, the difference being:

[0085] In step (6), 40g of epoxy resin and 17.5g of polyether modifier were placed in a three-necked flask, heated to 65°C, and stirred at 450rpm for 10 minutes to obtain mixture 3.

[0086] In step (7), 1g of 2,3-epoxypropyltrimethylammonium chloride is dissolved in 38.33g of deionized water to obtain an aqueous solution of 2,3-epoxypropyltrimethylammonium chloride.

[0087] In step (9), the mass of the defoamer is 0.3g, the mass of the leveling agent is 0.3g, the mass of the photosensitizer is 1.5g, and the mass of the silica-supported nano-silver is 0.07g.

[0088] Example 5

[0089] This embodiment is similar to the preparation method provided in Example 1, the difference being:

[0090] In step (6), 40g of epoxy resin and 17.5g of polyether modifier were placed in a three-necked flask, heated to 65°C, and stirred at 450rpm for 10 minutes to obtain mixture 3.

[0091] In step (7), 2g of 2,3-epoxypropyltrimethylammonium chloride is dissolved in 36.36g of deionized water to obtain an aqueous solution of 2,3-epoxypropyltrimethylammonium chloride.

[0092] In step (9), the mass of the defoamer is 0.3g, the mass of the leveling agent is 0.3g, the mass of the photoinitiator is 2g, and the mass of the photosensitizer is 1.5g.

[0093] Example 6

[0094] This embodiment is similar to the preparation method provided in Example 1, the difference being:

[0095] In step (6), 40g of epoxy resin and 17.5g of polyether modifier were placed in a three-necked flask, heated to 65°C, and stirred at 450rpm for 10 minutes to obtain mixture 3.

[0096] In step (7), 3g of 2,3-epoxypropyltrimethylammonium chloride was dissolved in 34.37g of deionized water to obtain an aqueous solution of 2,3-epoxypropyltrimethylammonium chloride.

[0097] In step (9), the mass of the defoamer is 0.3g, the mass of the leveling agent is 0.3g, the mass of the photoinitiator is 3g, the mass of the photosensitizer is 1.5g, and the mass of the silver-loaded silica sol is 0.03g.

[0098] Example 7

[0099] This embodiment is similar to the preparation method provided in Example 1, the difference being:

[0100] In step (6), 45g of epoxy resin and 20g of polyether modifier are placed in a three-necked flask, heated to 65°C, and stirred at 450 rpm for 10 minutes to obtain mixture 3.

[0101] In step (7), 1g of 2,3-epoxypropyltrimethylammonium chloride is dissolved in 29.9g of deionized water to obtain an aqueous solution of 2,3-epoxypropyltrimethylammonium chloride.

[0102] In step (9), the mass of the defoamer is 0.5g, the mass of the leveling agent is 0.5g, the mass of the photosensitizer is 2g, and the mass of the silver-loaded silica sol is 0.1g.

[0103] Example 8

[0104] This embodiment is similar to the preparation method provided in Example 1, the difference being:

[0105] In step (6), 45g of epoxy resin and 20g of polyether modifier are placed in a three-necked flask, heated to 65°C, and stirred at 450 rpm for 1 minute to obtain mixture 3.

[0106] In step (7), 2g of 2,3-epoxypropyltrimethylammonium chloride is dissolved in 27.93g of deionized water to obtain an aqueous solution of 2,3-epoxypropyltrimethylammonium chloride.

[0107] In step (9), the mass of the defoamer is 0.5g, the mass of the leveling agent is 0.5g, the mass of the photoinitiator is 3g, the mass of the photosensitizer is 2g, and the mass of the silver-loaded silica sol is 0.07g.

[0108] Example 9

[0109] This embodiment is similar to the preparation method provided in Example 1, the difference being:

[0110] In step (6), 45g of epoxy resin and 20g of polyether modifier are placed in a three-necked flask, heated to 65°C, and stirred at 450 rpm for 10 minutes to obtain mixture 3.

[0111] In step (7), 3g of 2,3-epoxypropyltrimethylammonium chloride is dissolved in 25.95g of deionized water to obtain an aqueous solution of 2,3-epoxypropyltrimethylammonium chloride.

[0112] In step (9), the mass of the defoamer is 0.5g, the mass of the leveling agent is 0.5g, the mass of the photoinitiator is 3g, and the mass of the photosensitizer is 2g.

[0113] Example 10

[0114] This embodiment is similar to the preparation method provided in Example 1, the difference being:

[0115] In step (6), 40g of epoxy resin and 17.5g of polyether modifier were placed in a three-necked flask, heated to 65°C, and stirred at 450rpm for 10 minutes to obtain mixture 3.

[0116] In step (7), 1g of 2,3-epoxypropyltrimethylammonium chloride is dissolved in 34.4g of deionized water to obtain an aqueous solution of 2,3-epoxypropyltrimethylammonium chloride.

[0117] In step (9), the mass of the defoamer is 0.5g, the mass of the leveling agent is 0.5g, the mass of the photoinitiator is 3g, the mass of the photosensitizer is 2g, and the mass of the silver-loaded silica sol is 0.1g.

[0118] Comparative Example 1

[0119] This embodiment is similar to the preparation method provided in Example 1, the difference being:

[0120] Step 2 (7) is omitted;

[0121] In step (8), under stirring at 850 rpm, 46.3 g of deionized water was added dropwise to mixture 3 at a rate of 10 parts by mass per minute, and kept warm for 60 minutes to obtain mixture 4;

[0122] In step (9), the mass of the silica-supported silver nanoparticles is 1.5g.

[0123] Comparative Example 2

[0124] This embodiment is similar to the preparation method provided in Example 1, the difference being:

[0125] Step 2 (7) is omitted;

[0126] In step (8), under stirring at 850 rpm, 46.77 g of deionized water was added dropwise to mixture 3 at a rate of 10 parts by mass per minute, and kept warm for 60 minutes to obtain mixture 4;

[0127] In step (9), the mass of the silica-supported silver nanoparticles is 0.03 g.

[0128] Comparative Example 3

[0129] This embodiment is similar to the preparation method provided in Example 1, the difference being:

[0130] Step 2 (7) is omitted;

[0131] In step (8), under stirring at 850 rpm, 45.8 g of deionized water was added dropwise to mixture 3 at a rate of 10 parts by mass per minute, and kept warm for 60 minutes to obtain mixture 4;

[0132] In step (9), the mass of the photoinitiator is 3g, and no silica-supported silver nanoparticles are added.

[0133] Comparative Example 4

[0134] This embodiment is similar to the preparation method provided in Example 1, the difference being:

[0135] In step (6), 40g of epoxy resin and 17.5g of polyether modifier were placed in a three-necked flask, heated to 65°C, and stirred at 450rpm for 10 minutes to obtain mixture 3.

[0136] In step (7), 7g of 2,3-epoxypropyltrimethylammonium chloride was dissolved in 32.4g of deionized water to obtain an aqueous solution of 2,3-epoxypropyltrimethylammonium chloride.

[0137] In step (9), the mass of the defoamer is 0.3g, the mass of the leveling agent is 0.3g, no photosensitizer or loaded silver silica sol is added.

[0138] Comparative Example 5

[0139] This embodiment is similar to the preparation method provided in Example 1, the difference being:

[0140] In step (6), 40g of epoxy resin and 17.5g of polyether modifier were placed in a three-necked flask, heated to 65°C, and stirred at 450rpm for 10 minutes to obtain mixture 3.

[0141] In step (7), 2g of 2,3-epoxypropyltrimethylammonium chloride is dissolved in 36.35g of deionized water to obtain an aqueous solution of 2,3-epoxypropyltrimethylammonium chloride.

[0142] In step (9), the mass of the defoamer is 0.3g, the mass of the leveling agent is 0.3g, the mass of the photoinitiator is 2g, the mass of the photosensitizer is 1.5g, and no silver-loaded silica sol is added.

[0143] Comparative Example 6

[0144] This embodiment is similar to the preparation method provided in Example 1, the difference being:

[0145] In step (6), 40g of epoxy resin and 17.5g of polyether modifier were placed in a three-necked flask, heated to 65°C, and stirred at 450rpm for 10 minutes to obtain mixture 3.

[0146] In step (7), 3g of 2,3-epoxypropyltrimethylammonium chloride is dissolved in 36.3g of deionized water to obtain an aqueous solution of 2,3-epoxypropyltrimethylammonium chloride.

[0147] In step (9), the mass of the defoamer is 0.3g, the mass of the leveling agent is 0.3g, the mass of the photoinitiator is 3g, the mass of the photosensitizer is 1.5g, and no silver-loaded silica sol is added.

[0148] Comparative Example 7

[0149] This embodiment is similar to the preparation method provided in Example 1, the difference being:

[0150] In step (6), 45g of epoxy resin and 20g of polyether modifier are placed in a three-necked flask, heated to 65°C, and stirred at 450 rpm for 10 minutes to obtain mixture 3.

[0151] In step (7), 1g of tetramethylammonium chloride is dissolved in 29.9g of deionized water to obtain an aqueous solution of tetramethylammonium chloride;

[0152] In step (8), under stirring at 850 rpm, an aqueous solution of tetramethylammonium chloride was added dropwise to the third mixture at a rate of 10 parts by mass per minute, and kept warm for 60 minutes to obtain mixture 4;

[0153] In step (9), the mass of the defoamer is 0.5g, the mass of the leveling agent is 0.5g, the mass of the photosensitizer is 2g, and the mass of the loaded silver silica sol is 0.1g.

[0154] Comparative Example 8

[0155] This embodiment is similar to the preparation method provided in Example 1, the difference being:

[0156] In step (6), 45g of epoxy resin and 20g of polyether modifier are placed in a three-necked flask, heated to 65°C, and stirred at 450 rpm for 10 minutes to obtain mixture 3.

[0157] In step (7), 2g of tetramethylammonium chloride is dissolved in 27.93g of deionized water to obtain an aqueous solution of tetramethylammonium chloride.

[0158] In step (8), under stirring at 850 rpm, an aqueous solution of tetramethylammonium chloride is added dropwise to mixture 3 at a rate of 10 parts by mass per minute, and kept warm for 60 minutes to obtain mixture 4;

[0159] In step (9), the mass of the defoamer is 0.5g, the mass of the leveling agent is 0.5g, the mass of the photoinitiator is 3g, the mass of the photosensitizer is 2g, and the mass of the silica-supported silver nanoparticles is 0.07g.

[0160] Comparative Example 9

[0161] This embodiment is similar to the preparation method provided in Example 1, the difference being:

[0162] In step (6), 45g of epoxy resin and 20g of polyether modifier are placed in a three-necked flask, heated to 65°C, and stirred at 450 rpm for 10 minutes to obtain mixture 3.

[0163] In step (7), 1g of tetramethylammonium chloride is dissolved in 25.95 parts by mass of deionized water to obtain an aqueous solution of tetramethylammonium chloride.

[0164] In step (8), under stirring at 850 rpm, an aqueous solution of tetramethylammonium chloride is added dropwise to mixture 3 at a rate of 10 parts by mass per minute, and kept warm for 60 minutes to obtain mixture 4;

[0165] In step (9), the mass of the defoamer is 0.5g, the mass of the leveling agent is 0.5g, the mass of the photoinitiator is 3g, and the mass of the photosensitizer is 2g.

[0166] Comparative Example 10

[0167] This embodiment is similar to the preparation method provided in Example 1, the difference being:

[0168] In step (6), 40g of epoxy resin and 17.5g of polyether modifier were placed in a three-necked flask, heated to 65°C, and stirred at 450rpm for 10 minutes to obtain mixture 3.

[0169] In step (7), 1g of 2,3-epoxypropyltrimethylammonium chloride is dissolved in 36.4g of deionized water to obtain an aqueous solution of 2,3-epoxypropyltrimethylammonium chloride.

[0170] In step (9), the mass of the defoamer is 1g, the mass of the leveling agent is 1g, the mass of the photoinitiator is 3g, the mass of the loaded silver silica sol is 0.1g, and no photosensitizer is added.

[0171] Antibacterial waterborne UV-curable coatings from Examples 1-10 and Comparative Examples 1-10 were subjected to emulsion stability tests, water resistance tests, initial antibacterial performance tests, and long-term antibacterial performance tests. The test methods are as follows:

[0172] Emulsion stability test

[0173] Take 200 mL of the paint sample and put it into a 250 mL stoppered, ground-glass, brown, transparent wide-mouth glass bottle. Fill the bottle to 15 mm from the stopper. Add a glass ball with a diameter of 7 mm ≤ r ≤ 10 mm into the bottle and then seal the bottle tightly. Weigh the sample. Conduct a natural storage stability test at 23 ± 2 °C and a high-temperature accelerated storage test at 50 ± 2 °C.

[0174] Emulsion color change test

[0175] After the prepared example and comparative samples were left to stand at room temperature for 30 days, 10 mL of the coating sample was taken and placed in a petri dish. The color difference between the two groups of samples was observed by visual colorimetry. The observer, wearing neutral-colored clothing, observed the color difference between the two groups of samples through a colorimetric box using natural light source and recorded the color difference components of the two groups of samples.

[0176] Visual assessment of color difference components

[0177] 0 No visible difference 1 Very slight, just barely noticeable. 2 Slight, with a clearly visible difference. 3 Medium difference 4 Quite a difference 5 Very big difference

[0178] Color difference component:

[0179] a) Tonal difference

[0180] Logo: DH (Tonal Difference)

[0181] Rating: Level 0 to 5; yellowish (ye), greenish (gr), reddish (re), bluish (bl)

[0182] Example: DH: 5ye (sample hue is level 5 and leans towards yellow)

[0183] b) Color saturation difference

[0184] Marker: DC (Color Difference)

[0185] Assessment: Level 0 to 5; greater than (+) or less than (-)

[0186] For example, DC, -2 (sample chroma less than level 2)

[0187] c) Difference in brightness

[0188] Marker: DL (Different Lightness)

[0189] Rating: Level 0 to 5; Brighter (+) or Darker (-)

[0190] Example: DL: -2 (Sample brightness is level 2 and is on the darker side)

[0191] Water resistance test

[0192] Making a test board: Applying a coating to a 70mm×150mm tinplate;

[0193] Add distilled or deionized water to the test tank. Water temperature: 23±2℃.

[0194] Immersion: Place three test plates in water, with 2 / 3 of the length of each test plate submerged in the water;

[0195] After the soaking time is over, take it out and blot it dry with filter paper. Record whether the sample has lost its gloss, changed color, bubbles, wrinkles, peeling, rust, etc., and the recovery time.

[0196] Initial and long-lasting antibacterial performance tests

[0197] Production and testing: A coating was prepared on a 70mm×150mm tinplate, with two coats applied. After the first coat dried, the second coat was applied, with a total coating thickness of less than 100μm. The coating was cured by UV light for 10–30 seconds. After coating, the test panels were conditioned at 23±2℃ and 50±5% relative humidity for 168 hours. The test panels were then cut into 10 pieces of 50mm×50mm size.

[0198] Initial antibacterial performance test

[0199] Preparation of test plates: Apply two coats of paint to a glass plate. After the first coat dries, apply the second coat. The total thickness of the coating is less than 100 μm. After exposure to ultraviolet light for 10–30 seconds, the coating is cured.

[0200] Add 0.4 mL to 0.5 mL of the test bacterial solution to the negative control sample (A), blank control sample (B), and antibacterial coating sample (C); cover sample (A), sample (B), and sample (C) with sterile covering film respectively, and incubate for 24 hours at (37±1)℃ and relative humidity RH>90%. Perform three parallel samples for each sample; after washing out the incubated samples, inoculate the washing solution into nutrient agar medium, incubate for 24 to 48 hours, count the viable bacteria, and calculate the antibacterial rate of the sample.

[0201] Long-lasting antibacterial performance test

[0202] Using a 30W ultraviolet lamp with a wavelength of 253.7nm, the antibacterial coating was irradiated for 100 hours at a distance of 0.8–1.0m from the test panel, and then the long-lasting antibacterial performance was tested according to the steps described above.

[0203] Based on the above testing methods, the material properties of the antibacterial waterborne UV-curable coatings of Examples 1-10 and Comparative Examples 1-10 were measured and are shown in Table 1.

[0204] Table 1. Material properties of antibacterial waterborne UV-curable coatings of Examples 1-10 and Comparative Examples 1-10

[0205]

[0206]

[0207] Note: In the table, Example 2 and Comparative Example 3 did not undergo antibacterial testing due to precipitation; the remaining " / " in the table indicate variables that were not changed when comparing the examples and comparative examples and were not tested accordingly.

[0208] As can be seen from Examples 1-3 and Comparative Examples 1-3 in the table, when the other components remain unchanged, the content of 2,3-epoxypropyltrimethylammonium chloride decreases to 0, the emulsion stability decreases from 45 days to 7, and problems such as stratification and antibacterial agent sedimentation occur; and the water resistance of the emulsion also changes from the original 18 hours of water resistance test with no obvious change in the test plate to 6 hours with rust spots appearing on the test plate. It can be seen that 2,3-epoxypropyltrimethylammonium chloride has a significant effect on improving the stability of the emulsion.

[0209] From Examples 1, 2, 3, 4, 7 and Comparative Example 1 in the table, it can be seen that, through the emulsion color change comparison, when the mass percentage concentration of silver loaded on nano-silica exceeds 0.05% of the dry weight of the emulsion, the emulsion will show slight color change. When the mass percentage concentration increases to 1.5%, the emulsion color change is obvious and turns brown.

[0210] As can be seen from Examples 1, 3, and 4 and Comparative Examples 1, 3, and 4 in the table, when adding the antibacterial agent alone, or when adding 2,3-epoxypropyltrimethylammonium chloride alone, the antibacterial grade of the paint film is Class II when the addition amount is 1.5 and the addition amount of 2,3-epoxypropyltrimethylammonium chloride is 7, but the emulsion stability decreases significantly. Adding nano-silica-loaded silver causes antibacterial agent sedimentation, and adding 2,3-epoxypropyltrimethylammonium chloride causes emulsion stratification. However, when both are added simultaneously, only a small amount is needed, and the antibacterial grade of the paint film increases significantly. This demonstrates that 2,3-epoxypropyltrimethylammonium chloride has a synergistic antibacterial effect.

[0211] As can be seen from Examples 7-9 and Comparative Examples 7-9 in the table, when 2,3-epoxypropyltrimethylammonium chloride is replaced with tetramethylammonium chloride, although the initial antibacterial performance of the paint film is not significantly affected, the antibacterial durability is significantly reduced, and the water resistance of the paint film is significantly reduced. This is because 2,3-epoxypropyltrimethylammonium chloride contains epoxy groups, which can undergo a cross-linking reaction with the resin during the cross-linking and curing of the paint film, and bond to the resin molecules, thereby reducing the gap between resin molecules inside the paint film and ensuring the long-term effectiveness of the antibacterial performance.

[0212] As can be seen from Examples 10 and 10 in the table, when a photosensitizer is added to the resin, although the resin curing time is not affected, the irradiation temperature during resin curing increases significantly. Therefore, the resin of this invention has a wide range of applications, and photosensitizers can be added as needed according to different curing temperatures.

[0213] In summary, this invention optimizes the preparation of a highly stable emulsion and reduces the sedimentation rate of the nano-silica antibacterial agent by adding polyether-modified epoxy resin, silver-loaded nano-silica, and 2,3-epoxypropyltrimethylammonium chloride to epoxy resin-based coatings. Specifically, this invention achieves synergistic and durable antibacterial properties between the silver-loaded nano-silica and 2,3-epoxypropyltrimethylammonium chloride, significantly reducing the amount of silver required in the coating.

[0214] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. An antibacterial water-based UV-curable coating, characterized in that, By mass, it includes the following raw material components: 35-45 parts epoxy resin; 15-20 parts of polyether modifier; 1-3 parts of 2,3-epoxypropyltrimethylammonium chloride; 2-3 parts of triphenylhexafluorophosphate thioonium salt; 0-2 parts of photosensitizer; Defoamer 0.1~1.0 parts; Leveling agent 0.1~1.0 parts; 0.01~0.1 parts of silver-supported silica sol; 25-35 parts water; The polyether modifier is prepared by mixing epoxy resin with polyethylene glycol with a molecular weight of 4000-8000 and stirring at 55-65°C for 20-30 minutes to obtain mixture 1; adding 5 parts by mass of potassium persulfate solution to mixture 1, wherein the mass percentage concentration of potassium persulfate solution is 0.8 wt.%, and stirring at 160°C for 360-390 minutes, and obtaining the polyether modifier after cooling.

2. The antibacterial waterborne UV-curable coating as described in claim 1, characterized in that, In the silver-loaded silica sol, silver particles are loaded on the surface or in the pores of the silica sol.

3. The antibacterial waterborne UV-curable coating as described in claim 2, characterized in that, The silver particles have a particle size of 20~60nm.

4. The antibacterial waterborne UV-curable coating as described in claim 1, characterized in that, The epoxy value of the epoxy resin is 0.44~0.51, and the epoxy resin includes bisphenol A glycidyl ether epoxy resin E51.

5. A method for preparing an antibacterial waterborne UV-curable coating as described in any one of claims 1 to 4, characterized in that, Includes the following steps: S10, Synthetic polyether modifier: Epoxy resin is mixed with polyethylene glycol with a molecular weight of 4000-8000 and stirred at 55-65°C for 20-30 minutes to obtain mixture 1; Add 5 parts by mass of potassium persulfate solution to mixture 1, wherein the mass percentage concentration of potassium persulfate solution is 0.8 wt.%, and stir at 160°C for 360-390 minutes. After cooling, a polyether modifier is obtained. S20, Synthesis of Silver-Loaded Silica Sol: Add 10 parts by mass of silver nitrate aqueous solution to 10 parts by mass of alkaline silica sol, stir and mix to obtain mixture 2; the mass percentage concentration of the alkaline silica sol is 30%, and the concentration of the silver nitrate aqueous solution is 0.05 mol / L; While stirring, 30 parts by mass of glucose aqueous solution were added to mixture 2 to obtain silicon-supported silver sol; the concentration of the glucose aqueous solution was 0.01 mol / L. The silicon-supported silver sol was freeze-dried to obtain silver-supported silicon sol. S30, Preparation of UV-curable coatings: Epoxy resin and polyether modifier are mixed to obtain mixture 3; Add a 2% (w / w) aqueous solution of 2,3-epoxypropyltrimethylammonium chloride to mixture 3, and stir at 60-65°C for 60-80 minutes to obtain mixture 4; At room temperature, according to the proportions described in claim 1, defoamer, leveling agent, photoinitiator, photosensitizer, and loaded silver silica sol are added to mixture 4 and mixed evenly to obtain an antibacterial waterborne photocurable coating.

6. The application of an antibacterial waterborne UV-curable coating as described in any one of claims 1 to 4, or an antibacterial waterborne UV-curable coating prepared by the preparation method as described in claim 5, in the preparation of an antibacterial paint film, characterized in that, Includes the following steps: S40, Preparation of antibacterial coating film: The antibacterial waterborne UV-curable coating obtained in step S30 is used to prepare a wet film by roller coating, dip coating, or spray coating. After drying or baking, it is cured by irradiation at a wavelength of 100W and 365~405nm for 10~30s in a UV curing oven to obtain the antibacterial coating film.

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