A method for preparing a hydrophilic antibacterial and antifungal photocurable coating

Abstract

This invention relates to the field of coating materials technology and discloses a method for preparing a hydrophilic antibacterial and mildew-resistant photocurable coating. The method involves synthesizing a tannic acid quaternary ammonium salt through an etherification reaction of tannic acid and a long-chain quaternary ammonium salt, followed by one-step photocrosslinking and curing to create a photocurable hydrophilic antibacterial coating of tannic acid quaternary ammonium salt. Subsequently, the coating is immersed in a zinc chloride solution, utilizing the ability of tannic acid to complex with metal ions to add zinc ions to the coating. The coating prepared by this invention exhibits excellent hydrophilic properties and long-lasting antibacterial effects, while also possessing anti-mildew properties.

Description

Technical Field

[0001] This invention relates to the field of antibacterial coating technology, and in particular to a method for preparing a hydrophilic antibacterial and mildew-resistant photocurable coating. Background Technology

[0002] Food packaging is an effective means of ensuring food safety and quality, and PET is one of the most widely used food packaging materials in daily life. Therefore, preparing antibacterial and antifungal coatings on the surface of PET is very important to prevent bacteria and mold on the outer packaging from harming the human body. Quaternary ammonium salts have been widely used in the preparation of antibacterial coatings due to their excellent broad-spectrum antibacterial effects, relatively simple synthesis, and cost-effectiveness. However, quaternary ammonium salts have high solubility in water, low thermal stability, and poor biocompatibility. Therefore, it is necessary to optimize quaternary ammonium salts to make them efficient, durable, stable, and non-toxic. Tannic acid (TA) is a polyphenol polymer extracted from plants. The presence of a large number of carboxyl and hydroxyl groups gives TA good biological activity. However, TA itself, as a natural antibacterial agent with high biocompatibility and non-toxicity, has poor lipid solubility and is easily affected by external conditions such as pH and temperature. Therefore, how to better combine highly biocompatible tannic acid with long-chain quaternary ammonium salts with strong antibacterial effects to form a coating and apply it to food packaging materials is a topic we are exploring. Summary of the Invention

[0003] Objective of the Invention: To address the problems existing in the prior art, this invention provides a method for preparing a hydrophilic antibacterial and antifungal photocurable coating. The method involves synthesizing a tannic acid quaternary ammonium salt through an etherification reaction with tannic acid and a long-chain quaternary ammonium salt, followed by one-step photocrosslinking and curing to create a photocurable hydrophilic antibacterial coating of tannic acid quaternary ammonium salt. Subsequently, the coating is immersed in a zinc chloride solution, utilizing the ability of tannic acid to complex with metal ions to add zinc ions to the coating. The coating prepared by this invention exhibits excellent hydrophilic properties and long-lasting antibacterial effects, while also possessing antifungal properties.

[0004] Technical solution: This invention provides a method for preparing a hydrophilic antibacterial and antifungal photocurable coating, comprising the following steps:

[0005] S1. The haloalkane and tertiary amine are slowly added to the solvent acetonitrile, and the reaction is carried out under magnetic stirring at a certain temperature. After evaporation and vacuum drying, a long-chain quaternary ammonium salt is obtained.

[0006] S2. Using the long-chain quaternary ammonium salt and tannic acid as raw materials, acetonitrile as solvent, and anhydrous potassium carbonate as catalyst, the reaction is carried out under nitrogen conditions and at a certain temperature to obtain a dark brown solution. The solution is filtered, the precipitate is collected, washed, centrifuged and the supernatant is removed, anhydrous ethanol and excess deionized water are added, the precipitate is collected, centrifuged and the supernatant is removed, and the solution is dried under vacuum to obtain the tannic acid quaternary ammonium salt monomer.

[0007] S3. Dissolve epoxy acrylate 6104, trimethylolpropane triacrylate, tripropylene glycol diacrylate, hydroxyethyl ester, photoinitiator, and the tannic acid quaternary ammonium salt monomer in an organic solvent, stir thoroughly, prepare a photocurable solution, and store it in the dark. Trimethylolpropane triacrylate is mainly used as a hardening agent; tripropylene glycol diacrylate is mainly used as a bifunctional monomer crosslinking agent to reduce the viscosity of the system; hydroxyethyl ester is mainly used to reduce viscosity and increase fluidity; benzophenone and 2-hydroxy-2-methyl-1-phenyl-1-propanone are used as photoinitiators, which are inexpensive, and the curing rate is faster when pyrolysis-type and hydrogen-abstract-type photoinitiators are used together.

[0008] S4. The photocuring solution is drop-coated onto the surface of the substrate and left to stand in the dark for a while. Then it is cured under ultraviolet light, washed multiple times with anhydrous ethanol and deionized water, dried, and then soaked in zinc chloride solution. After washing and drying again, a hydrophilic antibacterial and mildew-resistant photocuring coating is obtained.

[0009] Further, in S1, the haloalkane is one of 1,6-dibromohexane, 1,8-dibromooctane, and 1,12-dibromododecane; the tertiary amine is one of N,N-dimethyl-n-octylamine, N,N-dimethyldecylamine, and N,N-dimethyldodecylamine; and the molar ratio of the haloalkane to the tertiary amine is 1.1:1.

[0010] Furthermore, when the haloalkane is 1,6-dibromohexane, the tertiary amine is one of N,N-dimethyl-n-octylamine, N,N-dimethyldecylamine, and N,N-dimethyldodecylamine;

[0011] When the haloalkane is 1,8-dibromooctane, the tertiary amine is one of N,N-dimethyldecylamine and N,N-dimethyldodecylamine;

[0012] When the haloalkane is 1,8-dibromooctane, the tertiary amine is N,N-dimethyldodecylamine.

[0013] Preferably, in S1, the volume ratio of the haloalkane and tertiary amine to the volume of the acetonitrile is 1:1.

[0014] Preferably, in S1, the specific operation of evaporation is as follows: the solvent and excess impurities are removed by rotary evaporation under reduced pressure at 60°C in a rotary evaporator.

[0015] Preferably, in S1, the specific conditions for vacuum drying are: vacuum drying at 40°C for 24 hours.

[0016] Further, in S2, the molar ratio of tannic acid, long-chain quaternary ammonium salt and anhydrous potassium carbonate is 1:10:20; the amount of acetonitrile added is 1g tannic acid / 10ml acetonitrile.

[0017] Preferably, in S2, the specific conditions for vacuum drying are: vacuum drying at 40°C for 24 hours.

[0018] Further, in S3, the photoinitiator is benzophenone and 2-hydroxy-2-methyl-1-phenyl-1-propanone; the organic solvent is chloroform. Chloroform is a good organic solvent, colorless and transparent, and can dissolve various organic substances.

[0019] Furthermore, the mass ratio of epoxy acrylate 6104, trimethylolpropane triacrylate, tripropylene glycol diacrylate, hydroxyethyl acrylate, benzophenone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, chloroform, and tannic acid quaternary ammonium salt monomers in the photocuring solution is 40:10:14:4.5:0.02:0.01:30:0.5-2.

[0020] Furthermore, in S4, the concentration of the zinc chloride solution is 1g / 10ml-1g / 50ml.

[0021] Furthermore, in S4, the specific curing conditions are: curing light intensity of 250w; curing time of 10-15s.

[0022] Further, in S4, the substrate is made of PET or aluminum foil; the amount of the photocurable solution applied to the substrate surface is 35 μl / cm. 2 .

[0023] Preferably, in S4, the PET substrate has a size of 1.5cm*1.5cm, and the aluminum foil substrate has a size of 10cm*10cm.

[0024] Preferably, in step S4, the settling time is 15 minutes, allowing the photocuring solution to fully level on the PET substrate surface.

[0025] Preferably, in S1, the specific conditions for magnetic stirring are: stirring temperature of 40-50℃, stirring speed of 300r / min, and stirring time of 4-12h;

[0026] In S2, the specific conditions for the reaction are: the reaction temperature is 70-90℃ and the reaction time is 4-12h.

[0027] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0028] The tannic acid quaternary ammonium salt prepared in this invention exhibits both antibacterial and antifungal effects after complexing with zinc ions. Firstly, the tannic acid molecule contains numerous hydroxyl groups, which can form hydrogen bonds with water molecules, thereby enhancing the hydrophilicity of the coating. Secondly, the quaternary ammonium structure can kill bacteria attached to the surface, and the zinc ions complexed on the coating surface interfere with the metabolism and cell structure of mold, thus inhibiting its growth. Furthermore, the zinc ions can destroy the cell walls and membranes of mold, leading to its death, thereby ensuring the safety of PET packaging materials. The coating prepared in this invention has excellent hydrophilic properties, long-lasting antibacterial effects, and antifungal properties. Attached Figure Description

[0029] Figure 1 The tannic acid quaternary ammonium salt monomer TA-C6-N prepared in Example 1 + -C8 chemical structural formula;

[0030] Figure 2 The tannic acid quaternary ammonium salt monomer TA-C6-N prepared in Example 2 + -C10 chemical structural formula;

[0031] Figure 3 The tannic acid quaternary ammonium salt monomer TA-C8-N prepared in Example 3 + -C10 chemical structural formula;

[0032] Figure 4 The tannic acid quaternary ammonium salt monomer TA-C6-N prepared in Example 4 + -C12 chemical structural formula;

[0033] Figure 5 The tannic acid quaternary ammonium salt monomer TA-C8-N prepared in Example 5 + -C12 chemical structural formula;

[0034] Figure 6 The tannic acid quaternary ammonium salt monomer TA-C12-N prepared in Embodiment 6 + -C12 chemical structural formula;

[0035] Figure 7 The antibacterial effects of the PET film (a), the TA photocurable coating prepared in the comparative example (b), and the QTA-Zn-1 photocurable coating (c), QTA-Zn-2 photocurable coating (d), QTA-Zn-3 photocurable coating (e), QTA-Zn-4 photocurable coating (f), QTA-Zn-5 photocurable coating (g), and QTA-Zn-6 photocurable coating (h) prepared in Examples 1-6 on Gram-negative Escherichia coli were investigated.

[0036] Figure 8The water contact angle results are shown for the PET film (a), the TA photocurable coating prepared in the comparative example (b), and the QTA-Zn-1 photocurable coating (c), QTA-Zn-2 photocurable coating (d), QTA-Zn-3 photocurable coating (e), QTA-Zn-4 photocurable coating (f), QTA-Zn-5 photocurable coating (g), and QTA-Zn-6 photocurable coating (h) prepared in Examples 1-6.

[0037] Figure 9 SEM images of the TA photocurable coating (a) prepared for comparison and the hydrophilic antibacterial and antifungal photocurable coating (b) prepared by the method of the present invention;

[0038] Figure 10 The mold growth on the surface of strawberries after being packaged with aluminum foil was compared with the following samples: strawberry sample (a), original aluminum foil (b) and PET film (c), TA photocurable coating (d), QTA coating (e), TA-Zn coating (f), QTA-Zn-1 photocurable coating (g), QTA-Zn-2 photocurable coating (h), QTA-Zn-3 photocurable coating (i), QTA-Zn-4 photocurable coating (j), QTA-Zn-5 photocurable coating (k), and QTA-Zn-6 photocurable coating (l) prepared in Examples 1-6. Detailed Implementation

[0039] The present invention will now be described in detail with reference to the embodiments.

[0040] Implementation method 1:

[0041] 1) Synthesis of quaternary ammonium tannin: 1,6-dibromohexane and N,N-dimethyl-n-octylamine were slowly added to an equal volume of acetonitrile solvent at a molar ratio of 1.1:1. The prepared solution was magnetically stirred at 300 rpm for 6 h at 50 °C. The resulting solution was then subjected to rotary evaporation under reduced pressure at 60 °C to remove the solvent and excess impurities. The evaporated product was then vacuum dried at 40 °C for 24 h to obtain the desired C6-N + -C8 quaternary ammonium salt. The synthesized quaternary ammonium salt was reacted with tannic acid at a molar ratio of 10:1, with 10 ml of acetonitrile added as solvent for every 1 g of tannic acid. Anhydrous potassium carbonate was added as a catalyst at a molar ratio of 1:20 to tannic acid. The reaction was carried out under nitrogen atmosphere and at 85°C for 12 h. The resulting dark brown solution was filtered to obtain a precipitate. The precipitate was washed with deionized water, centrifuged, and the supernatant was removed. Anhydrous ethanol was added to dissolve the precipitate, and excess deionized water was added. After centrifugation, the supernatant was removed to obtain a brown precipitate. The precipitate was dried in a vacuum drying oven at 40°C for 24 h to obtain TA-C6-N. + -C8 tannic acid quaternary ammonium salt.

[0042] 2) Preparation of UV-curable coating: Using 40wt% UV-curable epoxy acrylate 6104 as the main raw material, 10wt% of trimethylolpropane triacrylate, 14wt% of tripropylene glycol diacrylate, 4.5wt% of hydroxyethyl acrylate, 0.5wt% of quaternary ammonium tannin, 0.02wt% of benzophenone, and 0.01wt% of 2-hydroxy-2-methyl-1-phenyl-1-propanone were added. A UV-curing solution was prepared in 30wt% chloroform, wrapped in aluminum foil, and stirred for 4 hours. PET substrates measuring 1.5cm*1.5cm and aluminum foil measuring 10cm*10cm were cut, ultrasonically cleaned with anhydrous ethanol and deionized water, and thoroughly dried. The prepared solution was applied by drop-coating to the surface of each PET and aluminum foil substrate at a rate of 35μl / cm. 2 The prepared photocurable solution was drop-coated, and the sample was allowed to stand in the dark for 15 minutes to allow it to fully level. The sample was then placed in a UV curing chamber and cured for 10 seconds under 250W UV light. After curing, the sample was thoroughly rinsed with anhydrous ethanol and deionized water, and then dried in a drying oven for 12 hours to obtain a photocurable tannic acid quaternary ammonium salt hydrophilic antibacterial coating. The coated sample was then immersed in a 1g / 10ml zinc chloride solution for 4 hours to allow zinc ions to complex with the tannic acid quaternary ammonium salt. After washing and drying, the hydrophilic antibacterial and antifungal photocurable coating QTA-Zn-1 was obtained.

[0043] The samples were subjected to antibacterial tests, and the plate count method was used to achieve a sterilization rate of over 95% against Escherichia coli.

[0044] Implementation Method 2:

[0045] 1) Synthesis of quaternary ammonium tannin: 1,6-dibromohexane and N,N-dimethyldecylamine were slowly added to an equal volume of acetonitrile solvent at a molar ratio of 1.1:1. The prepared solution was magnetically stirred at 300 r / min for 6 h at 50 °C. The resulting solution was then subjected to rotary evaporation at 60 °C under reduced pressure to remove the solvent and excess impurities. The evaporated product was then vacuum dried at 40 °C for 24 h to obtain the desired C6-N + -C10 quaternary ammonium salt. The synthesized quaternary ammonium salt was reacted with tannic acid at a molar ratio of 10:1, with 10 ml of acetonitrile added as solvent for every 1 g of tannic acid. Anhydrous potassium carbonate (at a molar ratio of 1:20 to tannic acid) was added as a catalyst. The reaction was carried out under nitrogen atmosphere and at 85°C for 12 h. The resulting dark brown solution was filtered to obtain a precipitate. The precipitate was washed with deionized water, centrifuged, and the supernatant was removed. Anhydrous ethanol was added to dissolve the precipitate, and excess deionized water was added. After centrifugation, the supernatant was removed to obtain a brown precipitate. This precipitate was dried in a vacuum drying oven at 40°C for 24 h to obtain TA-C6-N.+ -C10 tannic acid quaternary ammonium salt.

[0046] 2) Preparation of UV-curable coating: Using 40wt% UV-curable epoxy acrylate 6104 as the main raw material, 10wt% of trimethylolpropane triacrylate, 14wt% of tripropylene glycol diacrylate, 4.5wt% of hydroxyethyl acrylate, 0.5wt% of quaternary ammonium tannin, 0.02wt% of benzophenone, and 0.01wt% of 2-hydroxy-2-methyl-1-phenyl-1-propanone were added. A UV-curing solution was prepared in 30wt% chloroform, wrapped in aluminum foil, and stirred for 4 hours. PET substrates measuring 1.5cm*1.5cm and aluminum foil measuring 10cm*10cm were cut, ultrasonically cleaned with anhydrous ethanol and deionized water, and thoroughly dried. The prepared solution was applied by drop-coating to the surface of each PET and aluminum foil substrate at a rate of 35μl / cm. 2 The prepared photocurable solution was drop-coated, and the sample was allowed to stand in the dark for 15 minutes to allow it to fully level. The sample was then placed in a UV curing chamber and cured for 10 seconds under 250W UV light. After curing, the sample was thoroughly rinsed with anhydrous ethanol and deionized water, and then dried in a drying oven for 12 hours to obtain a photocurable tannic acid quaternary ammonium salt hydrophilic antibacterial coating. The coated sample was then immersed in a 1g / 10ml zinc chloride solution for 4 hours to allow zinc ions to complex with the tannic acid quaternary ammonium salt. After washing and drying, the hydrophilic antibacterial and antifungal photocurable coating QTA-Zn-2 was obtained.

[0047] The samples were subjected to antibacterial tests, and the plate count method showed a 100% sterilization rate against Escherichia coli.

[0048] Implementation Method 3:

[0049] 1) Synthesis of quaternary ammonium tannin: 1,8-dibromooctane and N,N-dimethyldecylamine were slowly added to an equal volume of acetonitrile solvent at a molar ratio of 1.1:1. The prepared solution was magnetically stirred at 300 r / min for 6 h at 50 °C. The resulting solution was then subjected to rotary evaporation under reduced pressure at 60 °C to remove the solvent and excess impurities. The product after rotary evaporation was then vacuum dried at 40 °C for 24 h to obtain the desired C8-N +-C10 quaternary ammonium salt. The synthesized quaternary ammonium salt was reacted with tannic acid at a molar ratio of 10:1, with 10 ml of acetonitrile added as solvent for every 1 g of tannic acid. Anhydrous potassium carbonate (at a molar ratio of 1:20 to tannic acid) was added as a catalyst, and the reaction was carried out under nitrogen atmosphere and at 85°C for 12 h. The resulting dark brown solution was filtered to obtain a precipitate, which was washed with deionized water, centrifuged, and the supernatant was removed. Anhydrous ethanol was added to dissolve the precipitate, and excess deionized water was added. After centrifugation, the supernatant was removed to obtain a brown precipitate, which was dried in a vacuum drying oven at 40°C for 24 h to obtain TA-C8-N. + -C10 tannic acid quaternary ammonium salt.

[0050] 2) Preparation of UV-curable coating: Using 40wt% UV-curable epoxy acrylate 6104 as the main raw material, 10wt% of trimethylolpropane triacrylate, 14wt% of tripropylene glycol diacrylate, 4.5wt% of hydroxyethyl acrylate, 0.5wt% of quaternary ammonium tannin, 0.02wt% of benzophenone, and 0.01wt% of 2-hydroxy-2-methyl-1-phenyl-1-propanone were added. A UV-curing solution was prepared in 30wt% chloroform, wrapped in aluminum foil, and stirred for 4 hours. PET substrates measuring 1.5cm*1.5cm and aluminum foil measuring 10cm*10cm were cut, ultrasonically cleaned with anhydrous ethanol and deionized water, and thoroughly dried. The prepared solution was applied by drop-coating to the surface of each PET and aluminum foil substrate at a rate of 35μl / cm. 2 The prepared photocurable solution was drop-coated, and the sample was allowed to stand in the dark for 15 minutes to allow it to fully level. The sample was then placed in a UV curing chamber and cured for 10 seconds under 250W UV light. After curing, the sample was thoroughly rinsed with anhydrous ethanol and deionized water, and then dried in a drying oven for 12 hours to obtain a photocurable tannic acid quaternary ammonium salt hydrophilic antibacterial coating. The coated sample was then immersed in a 1g / 10ml zinc chloride solution for 4 hours to allow zinc ions to complex with the tannic acid quaternary ammonium salt. After washing and drying, a hydrophilic antibacterial and antifungal photocurable coating, QTA-Zn-3, was obtained.

[0051] The samples were subjected to antibacterial tests, and the plate count method showed a 100% sterilization rate against Escherichia coli.

[0052] Implementation Method 4:

[0053] 1) Synthesis of quaternary ammonium tannin: 1,6-dibromohexane and N,N-dimethyldodecylamine were slowly added to an equal volume of acetonitrile solvent at a molar ratio of 1.1:1. The prepared solution was magnetically stirred at 300 r / min for 6 h at 50 °C. The resulting solution was then subjected to rotary evaporation under reduced pressure at 60 °C to remove the solvent and excess impurities. The product after rotary evaporation was then vacuum dried at 40 °C for 24 h to obtain the desired C8-N + -C12 quaternary ammonium salt. The quaternary ammonium salt was reacted with tannic acid at a molar ratio of 10:1, with 10 ml of acetonitrile added as solvent for every 1 g of tannic acid. Anhydrous potassium carbonate (at a molar ratio of 1:20 to tannic acid) was added as a catalyst. The reaction was carried out under nitrogen atmosphere and at 85°C for 12 h. The resulting dark brown solution was filtered to obtain a precipitate. The precipitate was washed with deionized water, centrifuged, and the supernatant was removed. Anhydrous ethanol was added to dissolve the precipitate, and excess deionized water was added. After centrifugation, the supernatant was removed to obtain a brown precipitate. This precipitate was dried in a vacuum oven at 40°C for 24 h to obtain TA-C8-N. + -C12 tannic acid quaternary ammonium salt.

[0054] 2) Preparation of UV-curable coating: Using 40wt% UV-curable epoxy acrylate 6104 as the main raw material, 10wt% of trimethylolpropane triacrylate, 14wt% of tripropylene glycol diacrylate, 4.5wt% of hydroxyethyl acrylate, 0.5wt% of quaternary ammonium tannin, 0.02wt% of benzophenone, and 0.01wt% of 2-hydroxy-2-methyl-1-phenyl-1-propanone were added. A UV-curing solution was prepared in 30wt% chloroform, wrapped in aluminum foil, and stirred for 4 hours. PET substrates measuring 1.5cm*1.5cm and aluminum foil measuring 10cm*10cm were cut, ultrasonically cleaned with anhydrous ethanol and deionized water, and thoroughly dried. The prepared solution was applied by drop-coating to the surface of each PET and aluminum foil substrate at a rate of 35μl / cm. 2 The prepared photocurable solution was drop-coated, and the sample was allowed to stand in the dark for 15 minutes to allow it to fully level. The sample was then placed in a UV curing chamber and cured for 10 seconds under 250W UV light. After curing, the sample was thoroughly rinsed with anhydrous ethanol and deionized water, and then dried in a drying oven for 12 hours to obtain a photocurable tannic acid quaternary ammonium salt hydrophilic antibacterial coating. The coated sample was then immersed in a 1g / 10ml zinc chloride solution for 4 hours to allow zinc ions to complex with the tannic acid quaternary ammonium salt. After washing and drying, a hydrophilic antibacterial and antifungal photocurable coating, QTA-Zn-4, was obtained.

[0055] The samples were subjected to antibacterial tests, and the plate count method showed a 100% sterilization rate against Escherichia coli.

[0056] Implementation Method 5:

[0057] 1) Synthesis of quaternary ammonium tannin: 1,8-dibromooctane and N,N-dimethyldodecylamine were slowly added to an equal volume of acetonitrile solvent at a molar ratio of 1.1:1. The prepared solution was magnetically stirred at 300 r / min for 6 h at 50 °C. The resulting solution was then subjected to rotary evaporation under reduced pressure at 60 °C to remove the solvent and excess impurities. The product after rotary evaporation was then vacuum dried at 40 °C for 24 h to obtain the desired C10-N + -C12 quaternary ammonium salt. The quaternary ammonium salt was reacted with tannic acid at a molar ratio of 10:1, with 10 ml of acetonitrile added as solvent for every 1 g of tannic acid. Anhydrous potassium carbonate (at a molar ratio of 1:20 to tannic acid) was added as a catalyst. The reaction was carried out under nitrogen atmosphere and at 85°C for 12 h. The resulting dark brown solution was filtered to obtain a precipitate. The precipitate was washed with deionized water, centrifuged, and the supernatant was removed. Anhydrous ethanol was added to dissolve the precipitate, and excess deionized water was added. After centrifugation, the supernatant was removed to obtain a brown precipitate. This precipitate was dried in a vacuum drying oven at 40°C for 24 h to obtain TA-C10-N. + -C12 tannic acid quaternary ammonium salt.

[0058] 2) Preparation of UV-curable coating: Using 40wt% UV-curable epoxy acrylate 6104 as the main raw material, 10wt% of trimethylolpropane triacrylate, 14wt% of tripropylene glycol diacrylate, 4.5wt% of hydroxyethyl acrylate, 0.5wt% of quaternary ammonium tannin, 0.02wt% of benzophenone, and 0.01wt% of 2-hydroxy-2-methyl-1-phenyl-1-propanone were added. A UV-curing solution was prepared in 30wt% chloroform, wrapped in aluminum foil, and stirred for 4 hours. PET substrates measuring 1.5cm*1.5cm and aluminum foil measuring 10cm*10cm were cut, ultrasonically cleaned with anhydrous ethanol and deionized water, and thoroughly dried. The prepared solution was applied by drop-coating to the surface of each PET and aluminum foil substrate at a rate of 35μl / cm. 2 The prepared photocurable solution was drop-coated, and the sample was allowed to stand in the dark for 15 minutes to allow it to fully level. The sample was then placed in a UV curing chamber and cured for 10 seconds under 250W UV light. After curing, the sample was thoroughly rinsed with anhydrous ethanol and deionized water, and then dried in a drying oven for 12 hours to obtain a photocurable tannic acid quaternary ammonium salt hydrophilic antibacterial coating. The coated sample was then immersed in a 1g / 10ml zinc chloride solution for 4 hours to allow zinc ions to complex with the tannic acid quaternary ammonium salt. After washing and drying, a hydrophilic antibacterial and antifungal photocurable coating, QTA-Zn-5, was obtained.

[0059] The samples were subjected to antibacterial tests, and the plate count method showed a 100% sterilization rate against Escherichia coli.

[0060] Implementation method 6:

[0061] 1) Synthesis of quaternary ammonium tannin: 1,12-dibromododecane and N,N-dimethyldodecylamine were slowly added to an equal volume of acetonitrile solvent at a molar ratio of 1.1:1. The prepared solution was magnetically stirred at 300 r / min for 6 h at 50 °C. The resulting solution was then subjected to rotary evaporation at 60 °C under reduced pressure to remove the solvent and excess impurities. The product after rotary evaporation was then vacuum dried at 40 °C for 24 h to obtain the desired C12-N + -C12 quaternary ammonium salt. The quaternary ammonium salt was reacted with tannic acid at a molar ratio of 10:1, with 10 ml of acetonitrile added as solvent for every 1 g of tannic acid. Anhydrous potassium carbonate (at a molar ratio of 1:20 to tannic acid) was added as a catalyst. The reaction was carried out under nitrogen atmosphere and at 85°C for 12 h. The resulting dark brown solution was filtered to obtain a precipitate. The precipitate was washed with deionized water, centrifuged, and the supernatant was removed. Anhydrous ethanol was added to dissolve the precipitate, and excess deionized water was added. After centrifugation and removal of the supernatant, a brown precipitate was obtained. This precipitate was dried in a vacuum drying oven at 40°C for 24 h to obtain TA-C12-N. + -C12 tannic acid quaternary ammonium salt.

[0062] 2) Preparation of UV-curable coating: Using 40wt% UV-curable epoxy acrylate 6104 as the main raw material, 10wt% of trimethylolpropane triacrylate, 14wt% of tripropylene glycol diacrylate, 4.5wt% of hydroxyethyl acrylate, 0.5wt% of quaternary ammonium tannin, 0.02wt% of benzophenone, and 0.01wt% of 2-hydroxy-2-methyl-1-phenyl-1-propanone were added. A UV-curing solution was prepared in 30wt% chloroform, wrapped in aluminum foil, and stirred for 4 hours. PET substrates measuring 1.5cm*1.5cm and aluminum foil measuring 10cm*10cm were cut, ultrasonically cleaned with anhydrous ethanol and deionized water, and thoroughly dried. The prepared solution was applied by drop-coating to the surface of each PET and aluminum foil substrate at a rate of 35μl / cm. 2 The prepared photocurable solution was drop-coated, and the sample was allowed to stand in the dark for 15 minutes to allow it to fully level. The sample was then placed in a UV curing chamber and cured for 10 seconds under 250W UV light. After curing, the sample was thoroughly rinsed with anhydrous ethanol and deionized water, and then dried in a drying oven for 12 hours to obtain a photocurable tannic acid quaternary ammonium salt hydrophilic antibacterial coating. The coated sample was then immersed in a 1g / 10ml zinc chloride solution for 4 hours to allow zinc ions to complex with the tannic acid quaternary ammonium salt. After washing and drying, a hydrophilic antibacterial and antifungal photocurable coating, QTA-Zn-6, was obtained.

[0063] The samples were subjected to antibacterial tests, and the plate count method showed a 100% sterilization rate against Escherichia coli.

[0064] Comparative example:

[0065] Preparation of TA UV-curable coating: Using 40wt% UV-curable epoxy acrylate 6104 as the main raw material, 10wt% of trimethylolpropane triacrylate, 14wt% of tripropylene glycol diacrylate, 4.5wt% of hydroxyethyl acrylate, 0.5wt% of tannic acid powder, 0.02wt% of benzophenone, and 0.01wt% of 2-hydroxy-2-methyl-1-phenyl-1-propanone were added. A UV-curing solution was prepared in 30wt% chloroform, wrapped in aluminum foil, and stirred for 4 hours. PET substrates measuring 1.5cm x 1.5cm and aluminum foil measuring 10cm x 10cm were cut, ultrasonically cleaned with anhydrous ethanol and deionized water, and thoroughly dried. The prepared solution was applied by drop-coating to the surface of each PET and aluminum foil substrate at a rate of 35μl / cm. 2 The prepared photocurable solution was drop-coated, and the sample was left to stand in the dark for 15 minutes to allow it to fully level. The sample was then placed in a UV curing chamber and cured for 10 seconds under 250W UV light. After curing, the sample was removed and thoroughly rinsed with anhydrous ethanol and deionized water, and then dried in a drying oven for 12 hours to obtain the TA photocurable coating.

[0066] The hydrophilic antibacterial and antifungal photocurable coatings prepared in Examples 1-6 were characterized and their performance was analyzed.

[0067] Figure 7 The antibacterial results of PET film (a), TA photocurable coating (b), QTA-Zn-1 photocurable coating (c), QTA-Zn-2 photocurable coating (d), QTA-Zn-3 photocurable coating (e), QTA-Zn-4 photocurable coating (f), QTA-Zn-5 photocurable coating (g), and QTA-Zn-6 photocurable coating (h) against *E. coli* were compared with those of embodiments 1-6. It was found that the photocurable tannic acid quaternary ammonium salt hydrophilic antibacterial coating prepared in this invention can effectively kill bacteria in contact with the coating surface. Furthermore, with different added antibacterial quaternary ammonium salt monomers, the antibacterial effect of the coating slightly weakens as the carbon chain of the quaternary ammonium salt shortens, but it still reaches over 95%.

[0068] Figure 8Water contact angle test results for PET film (a), TA UV-cured coating (b), QTA-Zn-1 UV-cured coating (c), QTA-Zn-2 UV-cured coating (d), QTA-Zn-3 UV-cured coating (e), QTA-Zn-4 UV-cured coating (f), QTA-Zn-5 UV-cured coating (g), and QTA-Zn-6 UV-cured coating (h): By comparing the water contact angle test results of embodiments 1-6, it can be seen that the tannic acid quaternary ammonium salt coating improves the hydrophilicity of the coating surface compared with the coating without quaternary ammonium salt (TA UV-cured coating) and the original PET coating. However, as the carbon chain length of the quaternary ammonium salt increases, its hydrophobicity gradually increases.

[0069] Figure 9 SEM images of the TA photocurable coating prepared for comparison with a 5g / 50ml zinc chloride solution (a) and the tannic acid quaternary ammonium salt coating prepared in this invention with a 5g / 50ml zinc chloride solution (b): By comparing the SEM images of the two surfaces, it can be found that, since TA molecules can complex zinc ions, an insoluble complex of zinc ions is formed on the coating surface, and the TA photocurable coating has a larger and denser surface size.

[0070] Figure 10 Strawberry sample (a), original aluminum foil (b), and PET film (c), and comparative examples of TA-cured coating (d), QTA coating (e), TA-Zn coating (f), QTA-Zn-1 (g), QTA-Zn-2 (h), QTA-Zn-3 (i), QTA-Zn-4 (j), QTA-Zn-5 (k), and QTA-Zn-6 (l) prepared in Examples 1-6, were used to treat the aluminum foil used for packaging strawberries with mold growth. Test results: Photos were taken after the cream strawberries were stored for 1, 4, and 7 days. By comparing the anti-mold test results of implementation methods 1-6, it can be seen that the original aluminum foil and coating did not have an anti-mold effect, and mold growth was not effectively inhibited by QTA and TA. However, after zinc ions were complexed on the surface, both the TA photocured coating and the QTA coating with different carbon chain lengths had excellent anti-mold effects on the surface of the strawberries. Furthermore, with the dual effect of the antibacterial effect of QTA and the anti-mold effect of zinc ions, the longer the carbon chain of the coating, the better the surface of the strawberries remained, only becoming lighter in color with the loss of moisture.

[0071] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent transformations or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a hydrophilic antibacterial and mildew resistant photocured coating, characterized by, It comprises the following steps: S1. Slowly add halogenated hydrocarbon and tertiary amine into solvent acetonitrile, magnetically stir the reaction at a certain temperature, evaporate, vacuum dry, and obtain long-chain quaternary ammonium salt; S2. Take the long-chain quaternary ammonium salt and tannic acid as raw materials, acetonitrile as solvent, and anhydrous potassium carbonate as catalyst, react fully under nitrogen condition and at a certain temperature, obtain dark brown solution, extract, take the precipitate, wash, centrifuge to remove supernatant, then add anhydrous ethanol and excess deionized water, precipitate, centrifuge to remove supernatant, vacuum dry, and obtain tannic acid quaternary ammonium salt monomer; S3. Dissolve epoxy acrylate 6104, trimethylolpropane triacrylate, tripropylene glycol diacrylate, hydroxyethyl ester, and photoinitiator in organic solvent, stir fully, configure photocuring solution, and store in dark; S4. Drop coat the photocuring solution on the surface of substrate, stand for a while in dark environment, then place under ultraviolet light for curing, wash with anhydrous ethanol and deionized water for several times, dry, immerse in zinc chloride solution, wash and dry again, and obtain hydrophilic antibacterial and mildew-proof photocured coating.

2. The method for preparing the hydrophilic antibacterial and antifungal photocurable coating according to claim 1, characterized in that: In S1, the halogenated hydrocarbon is one of 1,6-dibromohexane, 1,8-dibromooctane, and 1,12-dibromododecane; the tertiary amine is one of N,N-dimethyl-n-octylamine, N,N-dimethyldecylamine, and N,N-dimethyldodecylamine; and the molar ratio of halogenated hydrocarbon to tertiary amine is 1.1:

1.

3. The preparation method of the hydrophilic antibacterial and mildew-proof photocured coating according to claim 2, characterized in that: when the halogenated hydrocarbon is 1,6-dibromohexane, the tertiary amine is one of N,N-dimethyl-n-octylamine, N,N-dimethyldecylamine, and N,N-dimethyldodecylamine; when the halogenated hydrocarbon is 1,8-dibromooctane, the tertiary amine is one of N,N-dimethyldecylamine and N,N-dimethyldodecylamine; when the halogenated hydrocarbon is 1,8-dibromooctane, the tertiary amine is N,N-dimethyldodecylamine.

4. The method for preparing the hydrophilic antibacterial and antifungal photocurable coating according to claim 1, characterized in that: In S2, the molar ratio of tannic acid, long-chain quaternary ammonium salt, and anhydrous potassium carbonate is 1:10:20; and the addition amount of acetonitrile is 1 g of tannic acid per 10 ml of acetonitrile.

5. The method for preparing the hydrophilic antibacterial and antifungal photocurable coating according to claim 1, characterized in that: In S3, the photoinitiator is benzophenone and 2-hydroxy-2-methyl-1-phenyl-1-propanone; and the organic solvent is chloroform.

6. The method for preparing the hydrophilic antibacterial and antifungal photocurable coating according to claim 5, characterized in that: The mass ratio of epoxy acrylate 6104, trimethylolpropane triacrylate, tripropylene glycol diacrylate, hydroxyethyl ester, benzophenone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, chloroform, and tannic acid quaternary ammonium salt monomer in the photocuring solution is 40:10:14:4.5:0.02:0.01:30:0.5-2.

7. The method for preparing the hydrophilic antibacterial and antifungal photocurable coating according to claim 1, characterized in that: In S4, the concentration of the zinc chloride solution is 1 g / 10 ml-1 g / 50 ml.

8. The method for preparing the hydrophilic antibacterial and antifungal photocurable coating according to claim 1, characterized in that: In S4, the specific conditions for curing are as follows: the curing light intensity is 250 w; and the curing time is 10-15 s.

9. The method for preparing the hydrophilic antibacterial and antifungal photocurable coating according to claim 1, characterized in that: In S4, the material of the substrate is PET or aluminum foil; the drop coating amount of the photocuring solution on the surface of the substrate is 35 μl / cm 2 .

10. The method of claim 1-9, wherein the method is characterized by: In S1, the specific conditions for magnetic stirring are as follows: the stirring temperature is 40-50℃, the stirring speed is 300 r / min, and the stirring time is 4-12 h. In S2, the specific conditions of the reaction are as follows: the reaction temperature is 70-90°C, and the reaction time is 4-12h.

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