Self-repairing antibacterial water-based cathode electrophoretic paint and preparation method thereof
By introducing Cu2+ and Ag+ antibacterial components and a dynamic cross-linking network into the cathodic electrophoretic paint, the damage repair problem of traditional cathodic electrophoretic paint is solved, realizing the coating's self-repair and antibacterial properties, making it suitable for fields such as medical devices and food packaging.
Patent Information
- Application Number
- CN202511050414.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-29
- Publication Date
- 2025-11-11
AI Technical Summary
Traditional cathodic electrophoretic paints are susceptible to mechanical damage or chemical corrosion during long-term use, leading to coating failure. Furthermore, existing self-healing materials are incompatible with water-based cathodic electrophoretic systems, affecting coating performance.
An antibacterial component containing a Cu2+ and Ag+ composite salt solution is used. A stable coordination structure is formed between pyridine chain extenders and metal ions to construct a dynamic cross-linking network, enabling the coating to self-repair. Furthermore, the antibacterial mechanism of Cu2+ and Ag+ is utilized, combined with an organic bismuth catalyst to reduce side reactions and improve coating performance.
It achieves highly efficient self-healing and broad-spectrum antibacterial properties of the coating, significantly extends its service life, meets green manufacturing requirements, and is particularly suitable for fields such as medical devices and food packaging.
Smart Images
Figure CN120924148A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a self-healing antibacterial waterborne cathodic electrophoretic paint and its preparation method. Background Technology
[0002] Currently, cathodic electrocoating, as an environmentally friendly coating, is widely used in the automotive, home appliance, and machinery manufacturing industries due to its advantages of high penetration, corrosion resistance, and suitability for coating complex workpieces. However, traditional cathodic electrocoating is susceptible to mechanical damage (such as scratches and impacts) or chemical corrosion during long-term use, leading to coating failure. Currently, the industry mainly improves coating durability by optimizing the resin structure or adding anti-corrosion additives, but these methods lack the ability to actively repair existing microcracks or damage, limiting their further application in high-reliability scenarios.
[0003] With the development of materials science, self-healing polymers have become a research hotspot due to their ability to mimic the self-healing properties of biological systems. Self-healing materials can autonomously repair cracks and extend material lifespan without external intervention through mechanisms such as dynamic chemical bonds (e.g., metal coordination bonds, hydrogen bonds) or the release of repair agents from microcapsules. Among these, self-healing systems based on metal-ligand supramolecular polymers, due to their reversible coordination effects, possess both high mechanical strength and dynamic repair capabilities, providing a new approach to solving the damage repair problem of cathodic electrophoretic coatings.
[0004] Existing cathodic electrophoretic coatings use water-soluble cationic resins as film-forming bases, forming uniform coatings through electrodeposition, and feature low VOC emissions and high weather resistance. For example, sixth-generation cathodic electrophoretic coatings have achieved low-temperature curing (130℃) and high edge protection performance, but their core still relies on static cross-linking structures, which cannot cope with continuous damage under dynamic environments. The development of self-healing polymers began in the 1980s, with early research relying on microencapsulation of repair agents (such as epoxy resins) to achieve local repair through crack-triggered release. In recent years, self-healing systems based on dynamic chemical bonds have become mainstream, such as metal-ligand coordination systems and supramolecular cross-linking networks. Although self-healing materials have made significant progress, their application in cathodic electrophoretic coatings still faces challenges. Traditional self-healing systems (such as microcapsules) are incompatible with the water-soluble resin system of electrophoretic coatings, easily leading to a decline in coating performance. The reversibility of some dynamic bonds (such as covalent bonds) is insufficient, the repair speed is slow, and external stimuli (such as heating and light) are required, limiting practical applications. Existing research has not yet combined metal-ligand supramolecular polymers with aqueous cathodic electrophoresis systems, and the realization of antibacterial functions largely depends on physical doping. Summary of the Invention
[0005] This invention aims to provide a self-healing antibacterial waterborne cathodic electrophoretic paint and its preparation method. Through dynamic coordination network design, supramolecular monomers containing metal ions are introduced, and a reversible cross-linking structure is formed with the resin matrix through coordination bonds, thereby achieving self-repair of coating damage.
[0006] To address the above problems, the present invention provides a self-healing antibacterial waterborne cathodic electrophoretic paint coating and its preparation method, employing the following technical solution:
[0007] A self-healing antibacterial waterborne cathodic electrophoretic paint, the formulation of which, by mass parts, comprises: 0.1-1 parts catalyst, 40-50 parts polyether diol, 40-60 parts diisocyanate, 0.2-10 parts chain extender, 0.2-10 parts metal ions, and 40-60 parts neutralizer.
[0008] The polyether diol mentioned therein is one of polytetramethylene ether diol, polytetramethyl ether diol, polyethylene glycol, polypropylene glycol, and polytetrahydrofuran ether diol;
[0009] The diisocyanate mentioned is one of isophorone diisocyanate, diphenylmethane-4,4'-diisocyanate, polymethylene polyisocyanate, toluene diisocyanate, toluene-2,4-diisocyanate, hexamethylene diisocyanate, hexamethylene-1,6-diisocyanate, 1,6-hexane diisocyanate, dicyclohexylmethane diisocyanate, terephthalic diisocyanate, 1,5-pentamethylene diisocyanate, diphenylmethane diisocyanate, diphenylmethane diisocyanate, dicyclohexyl aliphatic diisocyanate, hydrogenated phenylenedimethylene diisocyanate, isophenylenedimethylene diisocyanate, tetramethylphenyl dimethyl diisocyanate, 1,5-naphthalene diisocyanate, 3,3'-dimethyl-4,4'-biphenyl diisocyanate, 2,2,4-trimethylhexane diisocyanate, and toluene-2,4-diisocyanate.
[0010] Furthermore, the chain extender is one or two of 2,6-pyridinediethanol, 2,4-dihydroxypyridine, 2,6-bis(1,2,3-triazol-4-yl)pyridine, 2,6-pyridinedicarboxylic acid, and 2,6-diaminopyridine.
[0011] Furthermore, the metal ion is Cu. 2+ and Ag + A salt solution containing Cu 2+ The salt solution is one of CuCl2, Cu(NO3)2, and CuSO4; containing Ag. + The salt solution is one of AgNO3, AgClO4, and AgCH3COO.
[0012] Furthermore, the neutralizing agent is either triethylamine or acetic acid.
[0013] Furthermore, the catalyst is an organic bismuth catalyst, specifically one or two of bismuth isooctanoate, bismuth laurate, bismuth neodecanoate, bismuth naphthenate, and bismuth carboxylate.
[0014] A method for preparing a self-healing antibacterial waterborne cathodic electrophoretic paint, comprising the following steps:
[0015] Step 1, prepolymer synthesis: First, the catalyst is added to the polyether diol and mixed evenly, and then mixed with diisocyanate;
[0016] Step 2, add a pyridine-containing chain extender and a Cu-containing... 2+ Ag + The salt solution continues to react, forming a polyurethane intermediate containing metal-ligands;
[0017] Step 3: Add a neutralizing agent to neutralize, then emulsify and desolventize.
[0018] Furthermore, during the preparation process, the reaction temperature is controlled between 60℃ and 90℃.
[0019] Furthermore, in step 1, both the catalyst and the polyether diol need to be dehydrated, wherein the polyether diol has a molecular weight of 1000-2000 g / mol.
[0020] Furthermore, in step 3, during the emulsification process, the mass ratio of prepolymer to deionized water is 1:2-6, and emulsification is carried out at high speed (1000-2000 rpm) for 0.5-5 hours.
[0021] The beneficial effects of this invention are as follows: This invention provides a self-healing antibacterial waterborne cathodic electrophoretic paint coating and its preparation method, using Cu... 2+ With Ag + The complex salt solution, acting as an antibacterial component, forms a stable coordination structure (metal-ligand complex) with metal ions through a pyridine chain extender. This structure not only achieves controlled and sustained release of the antibacterial component but also utilizes Cu... 2 +Disruption of bacterial electron transport chain and Ag +The dual mechanism of action, which damages cell membranes, exhibits broad-spectrum antibacterial properties against *Escherichia coli* (inhibition rate ≥99.8%) and *Staphylococcus aureus* (inhibition rate ≥99.5%). Simultaneously, a polyurethane network containing dynamic metal-ligand bonds is constructed through the stepwise polymerization reaction of a chain extender containing pyridine groups and diisocyanate groups. When the coating is subjected to mechanical damage, this network can achieve self-repair of cracks through reversible dissociation and recombination of metal-ligand bonds, with a repair efficiency exceeding 85%, significantly extending the coating's service life. The use of organic bismuth catalysts (such as bismuth isooctanoate and bismuth laurate) to replace traditional tin-based catalysts effectively reduces the side reaction (NCO + H2O → CO2↑ + amine) between water and isocyanate groups during the prepolymer synthesis stage, reducing CO2 generation by more than 70%. Furthermore, bismuth-based catalysts exhibit low toxicity and excellent biocompatibility, complying with EU REACH regulations and green manufacturing requirements. This coating combines the high penetration and corrosion resistance of traditional electrophoretic paints with antibacterial and self-healing properties through molecular design, making it particularly suitable for fields with stringent requirements for hygiene, safety, and durability, such as medical devices and food packaging. Attached Figure Description
[0022] Figure 1 The self-healing test of the elastomer obtained in step 3 of Embodiment 1 of the present invention is shown, and the self-healing process is observed under an optical microscope. Detailed Implementation
[0023] To better understand the technical solution provided by this invention, the invention will be further described below in conjunction with the accompanying drawings and specific embodiments.
[0024] In one embodiment, the preparation method of the self-healing antibacterial waterborne cathodic electrophoretic paint provided by the present invention is as follows:
[0025] Step 1: Add 0.71g of dehydrated and dried bismuth isooctanoate and 112g of dehydrated polytetramethylene ether glycol to a reaction vessel under continuous nitrogen purging. Control the reaction temperature at 75℃ and stir for 30 minutes to mix evenly. Then add 111.1g of isophorone diisocyanate and 100g of acetone and react for 2 hours.
[0026] Step 2: Add 13.9g of 2,6-pyridinediethanol, 4g of CuCl2 and 3.39g of AgNO3, raise the reaction temperature to 87℃ and continue the reaction for 3 hours;
[0027] Step 3: After adding 102g of triethylamine and continuing the reaction for 30min, pour the reactants into a polytetrafluoroethylene container and dry them in a vacuum oven to obtain an antibacterial self-healing polyurethane elastomer.
[0028] Step 4: Finally, add the product obtained in step 3 to 1000g of deionized water and emulsify and disperse it at a shear rate of 1500rpm for 2 hours to obtain the antibacterial self-healing polyurethane waterborne cathodic electrophoretic paint coating.
[0029] In the second embodiment, the preparation method of the self-healing antibacterial waterborne cathodic electrophoretic paint provided by the present invention is as follows:
[0030] Step 1: Add 0.6g of dehydrated and dried bismuth laurate and 100g of dehydrated polyethylene glycol to a reaction vessel under continuous nitrogen purging. Control the reaction temperature at 70℃, stir for 30 minutes to mix evenly, then add 84.1g of hexamethylene diisocyanate and 80g of acetone, and react for 3 hours.
[0031] Step 2: Add 10.9g of 2,6-diaminopyridine, 9.4g of Cu(NO3)2 and 5g of AgCH3COO, raise the reaction temperature to 85℃ and continue the reaction for 2 hours;
[0032] Step 3: After adding 60g of acetic acid and continuing the reaction for 30min, pour the reactants into a polytetrafluoroethylene container and dry them in a vacuum oven to obtain an antibacterial self-healing polyurethane elastomer.
[0033] Step 4: Finally, add the product obtained in step 3 to 1000g of deionized water and emulsify and disperse it at a shear rate of 1500rpm for 2 hours to obtain the antibacterial self-healing polyurethane waterborne cathodic electrophoretic paint coating.
[0034] In the third embodiment, the preparation method of the self-healing antibacterial waterborne cathodic electrophoretic paint provided by the present invention is as follows:
[0035] Step 1: Add 0.8g of dehydrated and dried bismuth neodecanoate and 122g of dehydrated polytetrahydrofuran ether diol to a reaction vessel under continuous nitrogen purging. Control the reaction temperature at 80℃ and stir for 30 minutes to mix evenly. Then add 157.4g of dicyclohexylmethane diisocyanate and 120g of acetone and react for 3 hours.
[0036] Step 2: Add 13.92g of 2,6-pyridinediethanol, 15.96g of CuSO4 and 1.6g of AgNO3, raise the reaction temperature to 85℃ and continue the reaction for 3 hours;
[0037] Step 3: After adding 102g of triethylamine and continuing the reaction for 30min, pour the reactants into a polytetrafluoroethylene container and dry them in a vacuum oven to obtain an antibacterial self-healing polyurethane elastomer.
[0038] Step 4: Finally, add the product obtained in step 3 to 1000g of deionized water and emulsify and disperse it at a shear rate of 1500rpm for 2 hours to obtain the antibacterial self-healing polyurethane waterborne cathodic electrophoretic paint coating.
[0039] In Comparative Example 1, the coating preparation method is as follows:
[0040] Step 1: Add 0.71g of dehydrated and dried bismuth isooctanoate and 112g of dehydrated polytetramethylene ether glycol to a reaction vessel under continuous nitrogen purging. Control the reaction temperature at 75℃ and stir for 30 minutes to mix evenly. Then add 111.1g of isophorone diisocyanate and 100g of acetone and react for 2 hours.
[0041] Step 2: Add 13.9g of 2,6-pyridinediethanol, raise the reaction temperature to 87℃, and continue the reaction for 3 hours;
[0042] Step 3: After adding 102g of triethylamine and continuing the reaction for 30min, pour the reactants into a polytetrafluoroethylene container and dry them in a vacuum oven to obtain an antibacterial self-healing polyurethane elastomer.
[0043] Step 4: Finally, add the product obtained in Step 3 to 1000g of deionized water and emulsify and disperse at a shear rate of 1500rpm for 2 hours to obtain the antibacterial self-healing polyurethane waterborne cathodic electrophoretic coating. In this comparative example, no metal ions were added, and the antibacterial properties of the coating were significantly reduced, and it had no repair ability.
[0044] In Comparative Example 2, the coating preparation method is as follows:
[0045] Step 1: Add 0.71g of dehydrated and dried bismuth isooctanoate and 112g of dehydrated polytetramethylene ether glycol to a reaction vessel under continuous nitrogen purging. Control the reaction temperature at 75℃ and stir for 30 minutes to mix evenly. Then add 111.1g of isophorone diisocyanate and 100g of acetone and react for 2 hours.
[0046] Step 2: Add 6.2g of ethylene glycol, 4g of CuCl2, and 3.39g of AgNO3, raise the reaction temperature to 87℃, and continue the reaction for 3 hours;
[0047] Step 3: After adding 102g of triethylamine and continuing the reaction for 30min, pour the reactants into a polytetrafluoroethylene container and dry them in a vacuum oven to obtain an antibacterial self-healing polyurethane elastomer.
[0048] Step 4: Finally, add the product obtained in Step 3 to 1000g of deionized water and emulsify and disperse at a shear rate of 1500rpm for 2 hours to obtain an antibacterial self-healing polyurethane waterborne cathodic electrophoretic coating. In this comparative example, the chain extender does not contain a pyridine structure and cannot form a metal-ligand coordination structure, resulting in poor mechanical properties and weak antibacterial activity of the coating.
[0049] In Comparative Example 3, the coating preparation method is as follows:
[0050] Step 1: Add 0.79g of bismuth isooctanoate with a water content of 10% and 112g of dehydrated polytetramethylene ether glycol to a reaction vessel under continuous nitrogen purging. Control the reaction temperature at 75℃ and stir for 30 minutes to mix evenly. Then add 111.1g of isophorone diisocyanate and 100g of acetone and react for 2 hours.
[0051] Step 2: Add 13.9g of 2,6-pyridinediethanol, 4g of CuCl2, and 3.39g of AgNO3, raise the reaction temperature to 87℃, and continue the reaction for 3 hours;
[0052] Step 3: After adding 102g of triethylamine and continuing the reaction for 30min, pour the reactants into a polytetrafluoroethylene container and dry them in a vacuum oven to obtain an antibacterial self-healing polyurethane elastomer.
[0053] Step 4: Finally, add the product obtained in Step 3 to 1000g of deionized water and emulsify and disperse at a shear rate of 1500rpm for 2 hours to obtain the antibacterial self-healing polyurethane waterborne cathodic electrophoretic coating. In this comparative example, the catalyst was not dehydrated, and the presence of moisture in the catalyst led to incomplete synthesis of the prepolymer, resulting in a decrease in the self-healing efficiency of the coating.
[0054] Table 1 shows the antibacterial efficacy data of the examples and comparative examples. The inhibition rate (%) against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) was tested after 24 hours using the plate count method.
[0055]
[0056] As can be seen from Table 1, Cu 2+ With Ag + The combination (as in Examples 1-3) showed an inhibition rate of greater than 99% against both types of bacteria, Ag + Disruption of cell membranes, Cu 2+Inhibiting enzyme activity creates a dual antibacterial mechanism. In this type of metal-ligand polyurethane, the coordination of the pyridine ring is key to maintaining the stability of the metal ions. In Comparative Example 2, the antibacterial rate plummeted to below 42% due to the use of ethylene glycol instead of pyridine chain extenders. Furthermore, catalyst dehydration (Comparative Example 3) and optimization of emulsification conditions can improve the integrity of the coating structure, indirectly enhancing the sustained-release performance of the antibacterial components.
[0057] Appendix Figure 1 The self-healing test of the elastomer obtained in step 3 of Example 1 was conducted by observing the self-healing process under an optical microscope. The experiment was carried out at 37°C. The cross-shaped scratches on the surface of the elastomer were basically repaired in 5 hours, indicating that the material has a good self-healing ability.
[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the technical solutions. Those skilled in the art should understand that those aspects of the present invention...
[0059] The technical solution may be modified or replaced equivalently without departing from the purpose and scope of this technical solution.
[0060] All such claims should be covered within the scope of the claims of this invention.
Claims
1. A self-healing antibacterial waterborne cathodic electrophoretic paint coating, characterized in that, Its formula, expressed in parts by weight, includes: 0.1-1 parts catalyst, 40-50 parts polyether diol, 40-60 parts diisocyanate, 0.2-10 parts chain extender, 0.2-10 parts metal ions, and 40-60 parts neutralizer. The polyether diol mentioned therein is one of polytetramethylene ether diol, polytetramethyl ether diol, polyethylene glycol, polypropylene glycol, and polytetrahydrofuran ether diol; The diisocyanate mentioned is one of isophorone diisocyanate, diphenylmethane-4,4'-diisocyanate, polymethylene polyisocyanate, toluene diisocyanate, toluene-2,4-diisocyanate, hexamethylene diisocyanate, hexamethylene-1,6-diisocyanate, 1,6-hexane diisocyanate, dicyclohexylmethane diisocyanate, terephthalic diisocyanate, 1,5-pentamethylene diisocyanate, diphenylmethane diisocyanate, diphenylmethane diisocyanate, dicyclohexyl aliphatic diisocyanate, hydrogenated phenylenedimethylene diisocyanate, isophenylenedimethylene diisocyanate, tetramethylphenyl dimethyl diisocyanate, 1,5-naphthalene diisocyanate, 3,3'-dimethyl-4,4'-biphenyl diisocyanate, 2,2,4-trimethylhexane diisocyanate, and toluene-2,4-diisocyanate.
2. The self-healing antibacterial waterborne cathodic electrophoretic paint coating according to claim 1, characterized in that, The chain extender is one or two of 2,6-pyridinediethanol, 2,4-dihydroxypyridine, 2,6-bis(1,2,3-triazol-4-yl)pyridine, 2,6-pyridinedicarboxylic acid, and 2,6-diaminopyridine.
3. The self-healing antibacterial waterborne cathodic electrophoretic paint coating according to claim 1, characterized in that, The metal ion mentioned is Cu 2+ and Ag + A salt solution containing Cu 2+ The salt solution is one of CuCl2, Cu(NO3)2, and CuSO4; containing Ag. + The salt solution is one of AgNO3, AgClO4, and AgCH3COO.
4. The self-healing antibacterial waterborne cathodic electrophoretic paint coating according to claim 1, characterized in that, The neutralizing agent is either triethylamine or acetic acid.
5. The self-healing antibacterial waterborne cathodic electrophoretic paint coating according to claim 1, characterized in that, The catalyst is an organic bismuth catalyst, specifically one or two of bismuth isooctanoate, bismuth laurate, bismuth neodecanoate, bismuth naphthenate, and bismuth carboxylate.
6. A method for preparing a self-healing antibacterial aqueous cathodic electrophoretic paint coating according to any one of claims 1-5, characterized in that, The steps are as follows: Step 1, prepolymer synthesis: First, the catalyst is added to the polyether diol and mixed evenly, and then mixed with diisocyanate; Step 2, add a pyridine-containing chain extender and a Cu-containing... 2+ Ag + The salt solution continues to react, forming a polyurethane intermediate containing metal-ligands; Step 3: Add a neutralizing agent to neutralize, then emulsify and desolventize.
7. The preparation method of a self-healing antibacterial waterborne cathodic electrophoretic paint according to claim 6, characterized in that, During the preparation process, the reaction temperature is controlled between 60℃ and 90℃.
8. The preparation method of a self-healing antibacterial waterborne cathodic electrophoretic paint according to claim 6, characterized in that, In step 1, both the catalyst and the polyether diol need to be dehydrated, and the polyether diol has a molecular weight of 1000-2000 g / mol.
9. The preparation method of a self-healing antibacterial waterborne cathodic electrophoretic paint according to claim 6, characterized in that, In step 3, during the emulsification process, the mass ratio of prepolymer to deionized water is 1:2-6, and emulsification is carried out at high speed (1000-2000 rpm) for 0.5-5 hours.