A method for preparing a hard, self-healing, antistatic waterborne polyurethane hybrid coating

Abstract

The present invention provides a method for preparing a hard, self-healing, antistatic waterborne polyurethane hybrid coating. The method comprises the following steps: injecting compound A, compound B, and a catalyst into a reactor, then adding a 2,2-dimethylolpropionic acid solution, adding triethylamine after the reaction, and continuing the reaction for 0.5 to 3 hours, then adding glycine amide and compound C to the polyurethane reaction system, and then adding water dropwise to obtain a polyurethane emulsion (WPUG). x ); Adjust the pH to 9.5-10.5, and drip the A-ZrO2 dispersion into the WPUG x In the emulsion, a stable WPUG is obtained x / A‑ZrO2 dispersion, coated on a substrate and dried at room temperature to obtain WPUG x / A-ZrO2 composite coating. The hybrid coating obtained by the present invention has excellent mechanical properties, self-healing and antistatic properties, expanding the commercial application field of water-based polymer coatings.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation of water-based coatings, and in particular relates to a method for preparing a water-based polyurethane environment-friendly anti-flash rust coating having mechanical properties, self-healing properties and anti-static properties. Background Art

[0002] Durable, self-healing water-based coatings, with their excellent conformability, recoverability, and environmental friendliness, have become a top choice for flexible electronic devices. However, most existing self-healing water-based polymers exhibit viscoelasticity, irreversible fatigue damage, and challenges in balancing self-healing functionality with mechanical properties, all of which stem from the inherent molecular structural conflict between flexibility and rigidity. The incorporation of nanofillers is currently the most widely used approach in the field of polymer materials.

[0003] Currently, inorganic nanomaterials remain the most convenient and reliable choice for fabricating composite systems. However, while the introduction of inorganic fillers enhances the mechanical properties of the coating, it significantly weakens the mobility of the polymer chains, sacrificing the self-healing ability of the polyurethane coating. Liu et al. (124791) prepared an epoxy-functionalized multifunctional filler by condensing TiO2 and γ-(2,3-epoxypropoxy)propyltrimethoxysilane (KH560) with hydroxyl groups. This filler was then added to polymethylvinylsiloxane (PMVS) to prepare a silicone rubber composite with improved mechanical, dielectric, and actuation properties. Zheng et al. (202205160) utilized the hydroxyl condensation reaction of APTES to decorate the surface of VO2 particles, thereby preparing a temperature-driven composite aerogel. However, while the nanoparticles prepared by hydrolysis and condensation effectively enhanced the mechanical properties and functionality of the matrix, they did not impart self-healing properties to the matrix. Although the hydrolysis and condensation of inorganic covalent bonds in nanofillers have long been known, their potential as a self-healing mechanism has been overlooked. By integrating dynamic reversible bonds directly into the nanoparticles themselves, the robustness of the nanocomposite can be enhanced while maintaining the inherent self-healing ability of the composite system. To our knowledge, previous studies have not provided evidence to successfully achieve the coordination of inconsistent properties in polyurethane coatings through condensation and hydrolysis reactions between zirconium particles and silica hydroxyl groups. Therefore, it is worthwhile to address the mechanical properties and self-healing ability of waterborne coatings by addressing the molecular structure of the polymer. In addition, coatings applied to electronic surfaces should also have antistatic properties. Therefore, it is considered extremely challenging to synergistically enhance the trade-off between toughness and flexibility of waterborne polyurethane systems and provide antistatic properties through complex molecular design. Summary of the Invention

[0004] The present invention aims to address the limitations of current technology by providing a method for preparing a hard, self-healing, antistatic waterborne polyurethane hybrid coating. This method utilizes the hydrolysis and condensation of inorganic covalent bonds to produce nanoparticles with rapidly reversible covalent bonds (Si-O-Zr bonds). These nanoparticles are then incorporated into a glycinamide-functionalized waterborne polyurethane matrix to create a durable, self-healing coating. Furthermore, the strong binding force of the Si-O-Zr bonds provides the polyurethane coating with excellent mechanical properties. The resulting hybrid coating, with its excellent mechanical, self-healing, and antistatic properties, expands the commercial application of waterborne polymer coatings.

[0005] The technical solutions of the present invention are as follows:

[0006] A method for preparing a hard, self-healing, antistatic waterborne polyurethane hybrid coating, the method comprising the following steps:

[0007] In the first step, zirconium n-propoxide (TPOZ) is added dropwise to glacial acetic acid, then added to deionized water at a stirring speed of 50-200 rpm and stirred for 5-20 minutes. Subsequently, 3-aminopropyltriethoxysilane (APTES) is added to the dispersion. The mixture is further stirred at room temperature for 12-36 hours to obtain an amino-functionalized zirconium dioxide dispersion (A-ZrO2).

[0008] The molar ratio of TPOZ to APTES is 1:1.0-3.0; 1 mmol of TPOZ is added to 2-4 mmol of glacial acetic acid and 10-20 mL of deionized water;

[0009] In the second step, compound A, compound B and the catalyst are injected into the reactor, followed by adding a solution of 2,2-dihydroxymethylpropionic acid in N,N-dimethylformamide, and reacting at 70-120°C under a nitrogen atmosphere for 1-5 hours with a stirring rate of 15-40 rpm; after the reaction temperature is lowered to 20-50°C, triethylamine is added and the reaction is continued for 0.5-3 hours, and then glycine amide and compound C are added to the polyurethane reaction system and stirred at 20-50°C for another 2-4 hours. Finally, deionized water is added dropwise to the obtained polyurethane prepolymer under high-speed stirring at 1000-2000 rpm, and stirring is continued for 0.5-2 hours to obtain a polyurethane emulsion (WPUG). x );

[0010] The mass ratio of compound A, compound B, 2,2-dihydroxymethylpropionic acid, glycineamide, compound C, catalyst, and triethylamine is 1:0.3-0.7:0.1-0.3:0.02-0.2:0.02-0.2:0.001-0.009:0.1-0.4; the mass ratio of prepolymer to deionized water is 1:2-10;

[0011] The compound A is one or more of polyether or polyester, specifically polytetramethylene ether diol or polycarbonate diol;

[0012] The compound B is one or more diisocyanates, specifically isophorone diisocyanate, hexamethylene diisocyanate or toluene diisocyanate;

[0013] The compound C is an alcohol capping agent, specifically ethanol, butanediol or methanol;

[0014] The catalyst is specifically one or more of stannous octoate, dibutyltin dilaurate, zinc naphthenate, and tetraisobutyl titanate;

[0015] The mass fraction of 2,2-dihydroxymethylpropionic acid in N,N-dimethylformamide solution is 20%-40%;

[0016] The third step is to add NH3·H2O to WPUG x The pH of the emulsion was adjusted to 9.5-10.5, and then the A-ZrO2 dispersion was dripped into the WPUG under magnetic stirring at 100-300 rpm. x In the emulsion, a stable WPUG is obtained x / A-ZrO2 dispersion

[0017] Among them, A-ZrO2 dispersion and WPUG x The mass ratio of the emulsion is 1:10~30

[0018] Step 4: Get the WPUG from step 3 x The WPUG was obtained by coating the A-ZrO2 dispersion on the substrate and drying it at room temperature for 12 to 36 hours. x / A-ZrO2 composite coating;

[0019] Among them, each 2.5×2.5cm 2 The base is coated with 1.0-5.0g of the dispersion;

[0020] The substrate is specifically tinplate, glass or polypropylene film.

[0021] The essential features of the present invention are:

[0022] This invention effectively enhances the mechanical properties of waterborne polyurethane by using inorganic nanoparticles with dynamically reversible covalent bonds. Leveraging the reversibility and antistatic properties of the inorganic nanoparticles, the authors address the difficulty in balancing mechanical and self-healing properties. By incorporating these nanoparticles into a glycinamide-functionalized waterborne polyurethane matrix, they develop a durable, self-healing coating. While achieving antistatic properties, this invention also addresses the conflict between mechanical performance and self-healing ability, potentially expanding the commercial application of waterborne polymer coatings.

[0023] The beneficial effects of the present invention are:

[0024] Most existing self-healing waterborne polymers exhibit viscoelasticity, irreversible fatigue damage, and difficulty in coordinating self-healing function with mechanical properties. Currently, there are few reports on enhancing the self-healing properties of composite coatings by using nanofillers with dynamic bonds. 2 ), elastic recovery, and antistatic capabilities of a waterborne polyurethane coating. Furthermore, the hybrid coating exhibited a healing efficiency of 92.58% while maintaining robust mechanical properties, demonstrating great potential for flexible electronics applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The FT-IR spectrum and NMR spectrum of A-ZrO2 obtained in Example 1 are shown in FIG. Figure 1 a is the FT-IR spectrum, Figure 1 b is the NMR Si spectrum;

[0026] Figure 2 WPUG obtained in Example 2-6 x FT-IR spectrum of the -1 The peak fitting results at ; where Figure 2 a is WPUG x FT-IR spectrum of Figure 2 b is WPUG0 at 1600-1800cm -1 The peak fitting results at ; Figure 2 c is WPUG 0.5 At 1600-1800cm -1 The peak fitting results at ; Figure 2 d is WPUG 1.0 At 1600-1800cm -1 The peak fitting results at ; Figure 2 e for WPUG 1.5 At 1600-1800cm -1 The peak fitting results at ; Figure 2 f is WPUG2.0 At 1600-1800cm -1 The peak fitting results at ;

[0027] Figure 3 WPUG obtained in Example 2-6 x Stress-strain curve of the film;

[0028] Figure 4 WPUG obtained in Example 6 and Example 7 x and WPUG x / Stress-strain curve of A-ZrO2 film;

[0029] Figure 5 WPUG obtained in Example 6 and Example 7 x and WPUG x Optical microscope photos of the self-healing process of A-ZrO2 scratches at different temperatures;

[0030] Figure 6 WPUG obtained in Example 6 and Example 7 x and WPUG x Optical microscope photos of the self-healing process of A-ZrO2 scratches under different humidity conditions; DETAILED DESCRIPTION

[0031] Example 1:

[0032] The synthesis of amino-functionalized zirconium dioxide particles (A-ZrO2) is carried out in the following steps:

[0033] TPOZ (1.7 g, 3.6 mmol) and glacial acetic acid (0.6 g, 10 mmol) were mixed and added to 40 mL of deionized water at 200 rpm, followed by stirring for 10 minutes. Subsequently, 3-aminopropyltriethoxysilane (APTES, 1.2 g, 5.4 mmol) was added to the dispersion. The mixture was stirred at room temperature for 24 hours to obtain amino-functionalized zirconium dioxide particles (A-ZrO2).

[0034] The structure of A-ZrO2 was characterized by Fourier transform infrared spectroscopy (FTIR) using a German Tensor-27 spectrometer with a scanning range of 500-4000 cm -1 , the results are as follows Figure 1 As shown in a. BET was analyzed by AVANCE 400 NMR spectrometer ( 29 Si MAS NMR) test, the results are as follows Figure 1 These results indicate that A-ZrO2 was successfully prepared.

[0035] Example 2:

[0036] The preparation of a water-based polyurethane emulsion comprises the following specific steps:

[0037] In the first step, 15.0 g of polytetramethylene glycol, 10.0 g of isophorone diisocyanate, and 0.03 g of dibutyltin dilaurate were injected into a flask equipped with a nitrogen inlet. Under a nitrogen atmosphere and a stirring speed of 30 rpm, 7.0 g of 2,2-dimethylolpropionic acid in N,N-dimethylformamide (the mass fraction of the solution is 28.6 wt%) was subsequently added and reacted at 80°C for 2 h. Then, the reaction system was cooled to 40°C, and triethylamine (2.4 g, 15.0 mmol) was added and stirred for 1 h. Next, 1.38 g of ethanol was added and the temperature was maintained for a further 3 h. Finally, deionized water (129 g) was added dropwise to the system under high-speed stirring at 1200 rpm and stirred for 1.5 h to obtain a polyurethane emulsion (WPUG0).

[0038] In the second step, 3.0 g of WPUG0 emulsion was directly dropped on a 2.5 × 2.5 cm 2 After being dried at room temperature for 24 hours, a water-based polyurethane coating was obtained.

[0039] The German Tensor-27 spectrometer was used to perform Fourier transform infrared spectroscopy (FTIR) testing on WPUG0. The results are as follows: Figure 2 a. WPUG0 coating at ~1110 cm -1 There is a clear absorption band at 1535cm, which corresponds to the stretching vibration of the ether bond in PTMG. -1 and ~3331cm -1 The absorption band at 1716cm is the bending and stretching vibration of the NH bond. -1 The strong absorption band at 1600-1800 cm-1 in the Fourier transform infrared spectrum was attributed to the stretching vibration of the carbonyl group in polyurethane and GCa. -1 The C=O absorption band, such as Figure 2 As shown in b. The C=O absorption band of the obtained WPUG0 can be divided into two sub-peaks: hydrogen bond (H-bonded) C=O and free C=O, and the hydrogen bond content is 39.5%. In addition, the particle size and distribution of the WPUG0 emulsion were tested by a dynamic light scattering particle size analyzer (XinSanSi, Shenzhen, China), and the results are shown in Table 1. The particle size of the emulsion is 49.2nm, the distribution index is 0.127, and the Zeta potential is -30.2mV, indicating that the WPUG0 emulsion has good stability. In addition, the mechanical properties of the WPUG0 film are shown in Figure 3The specific data are shown in Table 2. The tensile strength, elongation at break and toughness of WPUG0 are 10.8MPa, 688.9% and 57.5MJ / m respectively. 3 .

[0040] Example 3:

[0041] The preparation of a water-based polyurethane emulsion comprises the following specific steps:

[0042] In the first step, 15.0g of polytetramethylene glycol, 10.0g of isophorone diisocyanate and 0.03g of dibutyltin dilaurate were injected into a flask equipped with a nitrogen inlet. Under a nitrogen atmosphere and a stirring speed of 30rpm, 7.0g of 2,2-dihydroxymethylpropionic acid in N,N-dimethylformamide solution (the mass fraction of the solution is 28.6wt%) was then added and reacted at 80°C for 2h. Then, the reaction system was cooled to 40°C, and triethylamine (2.4g, 15.0mmol) was added and continued to stir for 1h. Next, 0.056g of glycine amide and 1.03g of ethanol were added, and the temperature was maintained to continue the reaction for 3h. Finally, deionized water (129g) was added dropwise to the system under high-speed stirring at 1200rpm, and stirring was continued for 1.5h to obtain a polyurethane emulsion (WPUG 0.5 ).

[0043] The second step is to add 3.0g WPUG 0.5 The emulsion is directly dropped on a 2.5×2.5cm 2 After being dried at room temperature for 24 hours, a water-based polyurethane coating was obtained.

[0044] The German Tensor-27 spectrometer was used to analyze the WPUG 0.5 The Fourier transform infrared spectroscopy (FTIR) test results are as follows Figure 2 a. WPUG 0.5 Coating at ~1110cm -1 There is a clear absorption band at 1535cm, which corresponds to the stretching vibration of the ether bond in PTMG. -1 and ~3331cm -1 The absorption band at 1716cm is the bending and stretching vibration of the NH bond. -1 The strong absorption band at is attributed to the stretching vibration of the carbonyl group in polyurethane and GCa. In order to further study the changes in hydrogen bonds in the WPU system after the addition of GCa, we analyzed the C=O absorption band at 1600-1800 cm-1 in the Fourier transform infrared spectrum by peak fitting. Figure 2 c. The obtained WPUG 0.5The C=O absorption band of WPUG can be divided into four sub-peaks: hydrogen bonded C=O and free C=O, which are derived from urea and polyurethane, respectively, with a hydrogen bond content of 40.6%. In addition, the WPUG was analyzed by dynamic light scattering particle size analyzer (XinSanSi, Shenzhen, China). 0.5 The particle size and distribution of the emulsion were tested, and the results are shown in Table 1. The particle size of the emulsion is 88.2nm, the distribution index is 0.174, and the Zeta potential is -28.5mV, indicating that WPUG 0.5 The emulsion has good stability. In addition, WPUG 0.5 The mechanical properties of the film such as Figure 3 As shown in the b curve, the specific data are shown in Table 2. WPUG 0.5 The tensile strength, elongation at break and toughness were 8.9MPa, 856.9% and 53.2MJ / m 3 .

[0045] Example 4:

[0046] The preparation of a water-based polyurethane emulsion comprises the following specific steps:

[0047] In the first step, 15.0g of polytetramethylene glycol, 10.0g of isophorone diisocyanate and 0.03g of dibutyltin dilaurate were injected into a flask equipped with a nitrogen inlet. Under a nitrogen atmosphere and a stirring speed of 30rpm, 7.0g of 2,2-dihydroxymethylpropionic acid in N,N-dimethylformamide solution (the mass fraction of the solution is 28.6wt%) was added and reacted at 80°C for 2h. Then, the reaction system was cooled to 40°C, and triethylamine (2.4g, 15.0mmol) was added and continued to stir for 1h. Next, 1.11g of glycine amide, 0.69g of ethanol and the temperature was maintained to continue the reaction for 3h. Finally, deionized water (129g) was added dropwise to the system under high-speed stirring at 1200rpm, and stirring was continued for 1.5h to obtain a polyurethane emulsion (WPUG 1.0 ).

[0048] The second step is to add 3.0g WPUG 1.0 The emulsion is directly dropped on a 2.5×2.5cm 2 After being dried at room temperature for 24 hours, a water-based polyurethane coating was obtained.

[0049] The German Tensor-27 spectrometer was used to analyze the WPUG 1.0 The Fourier transform infrared spectroscopy (FTIR) test results are as follows Figure 2 a. WPUG 1.0 Coating at ~1110cm -1 There is a clear absorption band at 1535cm, which corresponds to the stretching vibration of the ether bond in PTMG.-1 and ~3331cm -1 The absorption band at 1716cm is the bending and stretching vibration of the NH bond. -1 The strong absorption band at 1600-1800 cm-1 in the Fourier transform infrared spectrum was attributed to the stretching vibration of the carbonyl group in polyurethane and GCa. -1 The C=O absorption band, such as Figure 2 d. The obtained WPUG 1.0 The C=O absorption band can be divided into four sub-peaks: hydrogen bonded C=O and free C=O, which are derived from urea and polyurethane, respectively, with a hydrogen bond content of 43.6%. In addition, the particle size and distribution of the WPUG0 emulsion were tested by a dynamic light scattering particle size analyzer (XinSanSi, Shenzhen, China), and the results are shown in Table 1. The particle size of the emulsion is 111.6 nm, the distribution index is 0.184, and the Zeta potential is -31.9 mV, indicating that the WPUG0 1.0 The emulsion has good stability. In addition, WPUG 1.0 The mechanical properties of the film such as Figure 3 As shown in the middle c curve, the specific data are shown in Table 2. WPUG 1.0 The tensile strength, elongation at break and toughness are 6.4MPa, 1226.9% and 62.3MJ / m respectively. 3 .

[0050] Example 5:

[0051] The preparation of a water-based polyurethane emulsion comprises the following specific steps:

[0052] In the first step, 15.0g of polytetramethylene glycol, 10.0g of isophorone diisocyanate and 0.03g of dibutyltin dilaurate were injected into a flask equipped with a nitrogen inlet. Under a nitrogen atmosphere and a stirring speed of 30rpm, 7.0g of 2,2-dihydroxymethylpropionic acid in N,N-dimethylformamide solution (the mass fraction of the solution is 28.6wt%) was then added and reacted at 80°C for 2h. Then, the reaction system was cooled to 40°C, and triethylamine (2.4g, 15.0mmol) was added and continued to stir for 1h. Next, 1.67g of glycine amide and 0.34g of ethanol were added, and the temperature was maintained to continue the reaction for 3h. Finally, deionized water (129g) was added dropwise to the system under high-speed stirring at 1200rpm, and stirring was continued for 1.5h to obtain a polyurethane emulsion (WPUG 1.5 ).

[0053] The second step is to add 3.0g WPUG 1.5 The emulsion is directly dropped on a 2.5×2.5cm 2After being dried at room temperature for 24 hours, a water-based polyurethane coating was obtained.

[0054] The German Tensor-27 spectrometer was used to analyze the WPUG 1.5 The Fourier transform infrared spectroscopy (FTIR) test results are as follows Figure 2 a. WPUG 1.5 Coating at ~1110cm -1 There is a clear absorption band at 1535cm, which corresponds to the stretching vibration of the ether bond in PTMG. -1 and ~3331cm -1 The absorption band at 1716cm is the bending and stretching vibration of the NH bond. -1 The strong absorption band at 1600-1800 cm-1 in the Fourier transform infrared spectrum was attributed to the stretching vibration of the carbonyl group in polyurethane and GCa. -1 The C=O absorption band, such as Figure 2 The obtained WPUG 1.5 The C=O absorption band of WPUG can be divided into four sub-peaks: hydrogen bonded C=O and free C=O, which are derived from urea and polyurethane, respectively, with a hydrogen bond content of 48.9%. In addition, the WPUG was analyzed by dynamic light scattering particle size analyzer (XinSanSi, Shenzhen, China). 1.5 The particle size and distribution of the emulsion were tested, and the results are shown in Table 1. The particle size of the emulsion was 141.2 nm, the distribution index was 0.173, and the Zeta potential was -27.2 mV, indicating that the WPUG0 emulsion had good stability. 1.5 The mechanical properties of the film such as Figure 3 The specific data are shown in Table 2. 1.5 The tensile strength, elongation at break and toughness are 10.8MPa, 688.9% and 57.5MJ / m respectively. 3 .

[0055] Example 6:

[0056] The preparation of a water-based polyurethane emulsion comprises the following specific steps:

[0057] In the first step, 15.0g of polytetramethylene glycol, 10.0g of isophorone diisocyanate and 0.03g of dibutyltin dilaurate were injected into a flask equipped with a nitrogen inlet, and then 7.0g of 2,2-dihydroxymethylpropionic acid in N,N-dimethylformamide solution (the mass fraction of the solution was 28.6wt%) was added under a nitrogen atmosphere and a stirring speed of 30rpm, and the reaction was carried out at 80°C for 2h. Then, the reaction system was cooled to 40°C, and triethylamine (2.4g, 15.0mmol) was added and continued to stir for 1h. Then, 2.22g of glycine amide was added, and the temperature was maintained to continue the reaction for 3h. Finally, deionized water (129g) was added dropwise to the system under high-speed stirring at 1200rpm, and stirring was continued for 1.5h to obtain a polyurethane emulsion (WPUG 2.0 ).

[0058] The second step is to add 3.0g WPUG 2.0 The emulsion is directly dropped on a 2.5×2.5cm 2 After being dried at room temperature for 24 hours, a water-based polyurethane coating was obtained.

[0059] The German Tensor-27 spectrometer was used to analyze the WPUG 2.0 The Fourier transform infrared spectroscopy (FTIR) test results are as follows Figure 2 a. WPUG 2.0 Coating at ~1110cm -1 There is a clear absorption band at 1535cm, which corresponds to the stretching vibration of the ether bond in PTMG. -1 and ~3331cm -1 The absorption band at 1716cm is the bending and stretching vibration of the NH bond. -1 The strong absorption band at 1600-1800 cm-1 in the Fourier transform infrared spectrum was attributed to the stretching vibration of the carbonyl group in polyurethane and GCa. -1 The C=O absorption band, such as Figure 2 f. The obtained WPUG 2.0 The C=O absorption band of WPUG can be divided into four sub-peaks: hydrogen bonded C=O and free C=O, which are derived from urea and polyurethane, respectively, with a hydrogen bond content of 54.0%. In addition, the WPUG was analyzed by dynamic light scattering particle size analyzer (XinSanSi, Shenzhen, China). 2.0 The particle size and distribution of the emulsion were tested, and the results are shown in Table 1. The particle size of the emulsion is 183.2nm, the distribution index is 0.147, and the Zeta potential is -31.4mV, indicating that WPUG 2.0 The emulsion has good stability. In addition, WPUG 2.0The mechanical properties of the film such as Figure 3 The specific data are shown in Table 2. 2.0 The tensile strength, elongation at break and toughness are 4.9MPa, 2054.6% and 86.7MJ / m respectively. 3 In addition, we used optical microscopy to observe the 2.0 The surface scratch sealing of the coating was tested, e.g. Figure 5 and Figure 6 WPUG 2.0 After the coating was cured at 40℃ and 20%RH for 4h, there were still obvious scratch marks. At the same time, as shown in Table 3, WPUG 2.0 The surface resistivity of the coating is 1.52GΩ / cm 2 , its anti-static ability is poor.

[0060] Through implementation 2-6, we can see that with the increase of GCa content, the proportion of hydrogen bond C=O in the composite film increases from 39.5% (WPUG0) to 54.0% (WPUG 2.0 ), which indicates that glycine amide produces stronger hydrogen bonds in WPU. Moreover, with the increase of GCa content, WPUG x The film's tensile strength showed a significant downward trend, while its elongation at break and toughness increased. This is due to GCa's abundant hydrogen bonding, which effectively dissipates mechanical energy and thus improves toughness. Furthermore, GCa, as a terminal end-capping agent for the polyurethane chain, forms terminal hydrogen bonds, acting as a chain extender, lengthening the molecular chain and significantly increasing elongation.

[0061] Example 7: A specific method for preparing a water-based hybrid coating, the specific steps are as follows:

[0062] The first step is the same as in Example 1.

[0063] The second step is the same as the first step in Example 6.

[0064] In the third step, WPUG was treated by adding 37% NH3·H2O. 2.0 The pH value of the emulsion was adjusted to 10.5, and then 0.2 g of A-ZrO2 dispersion was dropped into 3.0 g of WPUG under magnetic stirring at 200 rpm. x In the emulsion, a stable WPUG is obtained 2.0 / A-ZrO2 dispersion. 3.0g of the dispersion was applied to a 2.5×2.5cm 2 WPUG was obtained by drying on release paper for 24 hours. 2.0 / A-ZrO2 composite coating.

[0065] WPUG 2.0The mechanical properties of the film such as Figure 4 As shown in the b curve, the specific data are shown in Table 2. WPUG 2.0 The tensile strength, elongation at break and toughness of / A-ZrO2 are 11.6MPa, 1788.1% and 119.5MJ / m 3 In addition, we used optical microscopy to observe the 2.0 The surface scratch sealing of the / A-ZrO2 coating was tested, as Figure 5 and Figure 6 WPUG 2.0 After being cured at 40℃ and 20%RH for 4h, the scratch marks on the / A-ZrO2 coating are still obvious. After being cured at 70℃ and 20%RH for 4h, the scratch marks become lighter. After being cured at 40℃ and 70%RH for 1h, the scratch marks disappear completely. 2.0 The surface resistivity of the / A-ZrO2 coating is 0.12 GΩ / cm 2 , indicating that it has good anti-static ability.

[0066] Through Examples 6 and 7, we can see that the polyurethane coatings composited with A-ZrO2 have both excellent mechanical properties and self-healing ability, which effectively extends the service life of the polyurethane coating in complex environments and enhances its protective ability for the substrate. This is because A-ZrO2 contains a rapidly reversible hard Zr-O-Si network, which not only imparts excellent mechanical properties to the polyurethane coating, but also does not impair its self-healing ability. In addition, A-ZrO2 can also impart excellent antistatic properties to the polyurethane coating, greatly expanding its development potential in the field of electronic components.

[0067] Table 1. WPUG x Particle size, particle size distribution and Zeta potential of emulsions

[0068]

[0069] Table 2. WPUG x and WPUG 2.0 Mechanical properties of A-ZrO2 films

[0070]

[0071] Table 3 WPUG 2.0 and WPUG 2.0 Surface resistance of / A-ZrO2 coating

[0072]

[0073] In summary, we have successfully prepared a nanohybrid coating with a reversible hydrogen bond network filled with rigid A-ZrO2 fillers. WPUG modified by the multiple hydrogen bonds of GCa and the strong covalent bonds of A-ZrO2 2.0 The WPU / A-ZrO2 coating exhibits excellent mechanical properties. Furthermore, scratch self-healing of the polyurethane coating containing the Zr-O-Si network is complete within 1 hour. This work provides a facile method for preparing strong, self-healing, and antistatic WPU coatings.

[0074] Matters not covered by the present invention are known technologies.

Claims

1. A method for preparing a hard, self-healing, antistatic waterborne polyurethane hybrid coating, characterized by The method comprises the following steps: In the first step, zirconium n-propoxide (TPOZ) is added dropwise to glacial acetic acid, then added to deionized water with stirring for 5-20 minutes to obtain a dispersion. Subsequently, 3-aminopropyltriethoxysilane (APTES) is added to the dispersion and stirred at room temperature for 12-36 hours to obtain an amino-functionalized zirconium dioxide dispersion (A-ZrO2). The molar ratio of TPOZ to APTES is 1:1.0-3.0; 1 mmol of TPOZ is added to 2-4 mmol of glacial acetic acid and 10-20 mL of deionized water; In the second step, compound A, compound B and the catalyst are injected into the reactor, followed by the addition of a solution of 2,2-dihydroxymethylpropionic acid in N,N-dimethylformamide, and the reaction is carried out at 70-120 ° C under a nitrogen atmosphere for 1-5 hours with a stirring rate of 15-40 rpm; after the reaction temperature is lowered to 20-50 ° C, triethylamine is added and the reaction is continued for 0.5-3 hours, and then glycine amide and compound C are added to the polyurethane reaction system and stirred at 20-50 ° C for another 2-4 hours; finally, deionized water is added dropwise to the obtained polyurethane prepolymer under high-speed stirring at 1000-2000 rpm, and the stirring is continued for 0.5-2 hours to obtain a polyurethane emulsion WPUG. x ; The mass ratio of compound A, compound B, 2,2-dimethylolpropionic acid, glycineamide, compound C, catalyst, and triethylamine is 1:0.3-0.7:0.1-0.3:0.02-0.2:0.02-0.2:0.001-0.009:0.1-0.4; the mass ratio of prepolymer to deionized water is 1:2-10; The compound A is one or more of polyether or polyester; The compound B is a diisocyanate; The compound C is an alcohol capping agent; The catalyst is one or more of stannous octoate, dibutyltin dilaurate, zinc naphthenate, and tetraisobutyl titanate; The mass fraction of 2,2-dihydroxymethylpropionic acid in N,N-dimethylformamide solution is 20%-40%; The third step is to add NH3•H2O to WPUG x The pH of the emulsion was adjusted to 9.5-10.5, and then the A-ZrO2 dispersion was dropped into the WPUG under magnetic stirring at 100-300 rpm. x In the emulsion, a stable WPUG is obtained x / A-ZrO2 dispersion; Among them, A-ZrO2 dispersion and WPUG x The mass ratio of the emulsion is 1:10~30; Step 4: Get the WPUG from step 3 x The WPUG was obtained by coating the A-ZrO2 dispersion on the substrate and drying it at room temperature for 12-36 h. x / A-ZrO2 composite coating; Among them, each 2.5×2.5 cm 2 The substrate was coated with 1.0-5.0 g of the dispersion.

2. The method for preparing a hard, self-healing, antistatic waterborne polyurethane hybrid coating according to claim 1, wherein the stirring speed in the first step is 50-200 rpm.

3. The method for preparing a hard, self-healing, antistatic waterborne polyurethane hybrid coating according to claim 1, wherein in the second step, the compound A is polytetramethylene ether glycol or polycarbonate diol; The compound B is isophorone diisocyanate, hexamethylene diisocyanate or toluene diisocyanate; The compound C is ethanol, butanediol or methanol.

4. The method for preparing a hard, self-healing, antistatic waterborne polyurethane hybrid coating according to claim 1, characterized in that The substrate is specifically tinplate, glass or polypropylene film.

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