Silver monatomic antibacterial and antiviral material, and preparation method and application thereof

Abstract

The application discloses a kind of silver monatomic antibacterial antiviral materials and its preparation method and application, belong to timber processing technical field.The preparation method of the above-mentioned silver monatomic antibacterial antiviral material includes: first, ZIF-8 is prepared, then by ammonium ceric nitrate is dissolved in isopropyl alcohol, titanium isopropoxide is added, precursor solution is obtained;ZIF-8 is added to precursor solution, and TiO2@ZIF-8 is prepared;Silver ammonia solution is configured, and silver ammonia solution is added to TiO2@ZIF-8 dispersion, and silver monatomic antibacterial antiviral material (Ag SACs) is prepared.The monatomic silver introduced in the application has good dispersity and chemical stability, can realize efficient antibacterial antiviral performance while avoiding the problem of activity decline caused by traditional nano-silver due to agglomeration, reduce the environmental burden brought by silver agent release, realize long-acting antibiosis.

Description

Technical Field

[0001] This invention relates to the field of antibacterial agent preparation technology, and in particular to a silver single-atom antibacterial and antiviral material, its preparation method, and its application. Background Technology

[0002] Bacteria and viruses are widespread in human living and working environments, and infectious diseases caused by pathogenic bacteria pose a serious threat to human life and health. Pathogens not only exist in living organisms, but also on the surfaces of materials that play an important role in their growth, proliferation, and spread.

[0003] Impregnated paper-faced engineered wood panels are decorative panels made with particleboard, blockboard, and other engineered wood products as the base material and impregnated paper as the surface material. They are widely used in furniture, accounting for more than 60% of all engineered wood panels. Impregnated paper-faced engineered wood panels play an important role in people's working and living environments, but they are also highly susceptible to becoming a medium for the spread of bacteria and viruses. How to solve indoor air pollution and reduce or eliminate the spread and harm of bacteria and viruses in the indoor environment has become a common topic for the entire industry worldwide.

[0004] In the prior art, the antibacterial properties of impregnated paper are generally achieved by adding an antibacterial agent to the impregnating adhesive. This requires the antibacterial agent to have good high-temperature resistance and good compatibility with the resin used for impregnation (mainly melamine-formaldehyde resin or urea-formaldehyde resin) and other additives (such as curing agents, release agents, penetrants, etc.). It should not affect the resin curing process, transparency, or cause the adhesive to deteriorate, and it should be able to be evenly dispersed in the impregnating adhesive without affecting the appearance of the decorative paper.

[0005] Silver nanoparticles (AgNPs) possess excellent antibacterial properties, but they are prone to aggregation during use, leading to a reduction in active sites and affecting antibacterial and antiviral efficacy. Furthermore, the release of silver ions may cause toxicity accumulation, compromising long-term safety. In existing technologies, CN117817771A modifies silver nanoparticles with chitosan to prevent aggregation, improve dispersion in resins, and enhance the antibacterial properties of impregnated paper. However, the utilization rate of silver needs further improvement. In contrast, single-atom silver (Ag SACs) disperse silver as individual atoms on a carrier, exhibiting both good stability and high activity. Compared to AgNPs, Ag SACs significantly improve silver utilization efficiency, reduce dosage, and minimize environmental risks.

[0006] CN112956493A discloses a method for preparing a single-atom silver bactericide. Silver nitrate and a carrier are added to a phenolic solution to obtain a mixed solution. The mixed solution is placed in an ice-water bath and subjected to a photocatalytic reaction under light irradiation, or the mixed solution is heated and stirred during the reaction. The product obtained from the reaction is cleaned of phenolic compounds and residual silver ions, and then dried to obtain the single-atom silver bactericide. This invention's preparation method successfully yields stable single-atom silver materials through photocatalytic or thermal reactions of silver nitrate under the action of phenolic compounds, avoiding the aggregation of silver atoms. However, the preparation of silver atoms inevitably requires photocatalytic or thermal reactions, leading to complex preparation conditions, and premature consumption of silver can affect long-term antibacterial performance. CN115735948A discloses a method for preparing a highly efficient single-atom silver bactericide material. It utilizes an oxide as a carrier, modifies the oxide with phenolic compounds, then anchors silver ions with the phenolic hydroxyl groups of the phenolic compounds to achieve uniform dispersion, and finally reduces the silver ions to single silver atoms through hydrogen reduction. This invention yields a highly efficient single-atom silver bactericidal material with low loading through a concise two-step process of phenolic compound modification and hydrogen reduction. In this material, silver is uniformly distributed on the carrier in the form of single atoms, achieving excellent bactericidal effects. However, using oxides as a carrier requires further improvement in compatibility with the resin matrix during the subsequent preparation of the impregnation adhesive; moreover, the low loading and excessively rapid release rate of oxides as a carrier prevent the achievement of long-lasting antibacterial effects. Summary of the Invention

[0007] To address the problems existing in the prior art, this invention provides a silver single-atom antibacterial and antiviral material, its preparation method, and its application. The preparation process of this invention is simple and convenient to operate. The introduced single-atom silver has good dispersibility and chemical stability, which can achieve high-efficiency antibacterial and antiviral performance while avoiding the problem of decreased activity caused by the aggregation of traditional nano-silver, reducing the environmental burden caused by the release of silver agents, and achieving long-lasting antibacterial effect.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0009] On the one hand, the present invention provides a method for preparing silver single-atom antibacterial and antiviral materials, specifically:

[0010] (1) Dissolve 1 part of cerium ammonium nitrate in 1000 parts of isopropanol and sonicate for 30 min to obtain a clear orange solution; then add 125 parts of titanium isopropoxide (IV) (TTIP, purity 97%) to the solution and stir magnetically for 30 min at room temperature. The resulting solution is the precursor solution.

[0011] (2) Dissolve 1 part of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) in 100 parts of methanol and stir until homogeneous. Dissolve 10 parts of 2-methylimidazole (2-mim) in 100 parts of methanol and add it to the above zinc nitrate hexahydrate methanol solution. Stir vigorously at room temperature for 24 hours. After the reaction is complete, centrifuge at 8000 rpm for 12 minutes to collect the reaction product and wash it three times with methanol. Place the collected white ZIF-8 powder in a vacuum drying oven and dry it at 60°C for 12 hours to obtain the final ZIF-8 product.

[0012] (3) Add 1 part of ZIF-8 to 20 parts of precursor solution, sonicate for 1 h, then centrifuge and wash, dry to obtain ZIF-8 material with amorphous TiO2 transparent coating, namely TiO2@ZIF-8.

[0013] (4) Weigh 1 part of silver nitrate (AgNO3) and place it in a 50 mL beaker. Add 10 parts of deionized water and stir with a glass rod until completely dissolved. Add dilute ammonia (5% by mass) dropwise to the above solution until the solution first becomes turbid and then becomes clear again, thus obtaining a freshly prepared silver ammonia solution.

[0014] (5) Add 1 part TiO2@ZIF-8 to 100 parts H2O to obtain a TiO2@ZIF-8 dispersion. Add 1 part silver ammonia solution to the above TiO2@ZIF-8 dispersion, stir at 4℃ for 5 h, filter the obtained solution, remove the supernatant, wash the obtained precipitate three times with ultrapure water, and dry in an oven at 60℃ for 12 h. Then, put the dried sample into a quartz tube and calcine at 200℃ for 12 h in a (N2 / H2=95:5) gas flow (40 mL min-1) to obtain silver single-atom antibacterial and antiviral materials (AgSACs).

[0015] On the other hand, the present invention also provides a silver single-atom antibacterial and antiviral material prepared by the above method.

[0016] Furthermore, the present invention also provides an application of the above-mentioned silver single-atom antibacterial and antiviral material in the preparation of antibacterial and antiviral impregnated paper decorative panels, including:

[0017] (1) The above-mentioned silver single-atom antibacterial and antiviral material is added to melamine-formaldehyde resin and mixed evenly to obtain an antibacterial and antiviral impregnating adhesive; the amount of the silver single-atom antibacterial and antiviral material is 1wt%-2wt% of the amount of melamine-formaldehyde resin.

[0018] Melamine-formaldehyde resin can be purchased commercially or prepared by the following method: formaldehyde, melamine, and distilled water are added to a three-necked flask equipped with a reflux condenser and a stirrer. The molar ratio of formaldehyde to melamine is 2:1. Then, the pH is adjusted to 9 with NaOH solution, and the reaction is stopped at 90°C when the water solubility ratio is 3, resulting in melamine-formaldehyde resin with a weight average molecular weight of 500.

[0019] (2) The raw paper is immersed in a urea-formaldehyde resin aqueous solution (urea-formaldehyde resin with a weight-average molecular weight of 900 and a mass content of 55%) for 45 seconds, then removed and dried at 110°C for 3 minutes to obtain paper I; then the antibacterial and antiviral coating is uniformly applied to paper I using a rubber roller, with a coating amount of 50 g / m 2 Dry at 110℃ for 2 minutes to obtain impregnated paper;

[0020] (3) Place the impregnated paper on a wood-based panel (e.g., plywood) and press it at 120°C and 0.7 MPa for 7 min to obtain an antibacterial and antiviral impregnated paper decorative panel.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] Significantly enhanced antibacterial and antiviral properties: The highly dispersed single-atom silver active sites in this invention have high surface energy, enabling them to interact efficiently with the protein and nucleic acid structures of bacteria and viruses, leading to cell membrane rupture or inactivation of viral capsid proteins, thereby significantly improving antibacterial and antiviral effects. Experimental results show that when Ag SACs are added at 1.0 wt%, the antibacterial rate against Escherichia coli and Staphylococcus aureus exceeds 99.9%, and the inactivation rate against influenza A virus (H3N2) reaches 99.99%, meeting the national Class I strong antibacterial standard.

[0023] Excellent structural stability and safety: Since silver atoms are fixed on the surface of TiO2@ZIF-8 carrier in a monodisperse form, it can effectively prevent the migration and aggregation of silver ions, avoid the problem of excessive release of silver ions during long-term use of traditional nano-silver, thereby reducing the risk of cumulative environmental toxicity and ensuring the safety and stability of the product under long-term indoor use.

[0024] Green and environmentally friendly with high resource utilization: The utilization rate of silver in this invention is several times higher than that of traditional nano-silver systems. While achieving the same antibacterial and antiviral effects, the amount of silver used is reduced by about 80%, significantly reducing production costs and environmental burden. No organic solvents or highly toxic additives are used in the entire preparation process, which is clean and mild, meeting the requirements of green manufacturing.

[0025] This invention uses ZIF-8 as a precursor, constructing a uniformly dispersed support structure on its surface through an amorphous TiO2 coating layer. Monodisperse loading of silver atoms is achieved through silver ammonia complex solution reduction followed by low-temperature calcination (200℃, N2 / H2 atmosphere), yielding single-atom silver catalytic centers with high stability and activity. These single-atom silver atoms are firmly anchored to the TiO2@ZIF-8 surface at the atomic level, effectively preventing silver agglomeration and migration. Ag SACs are uniformly dispersed and introduced into the melamine-formaldehyde resin system to form a composite impregnating adhesive with high stability, high reactivity, and excellent interfacial compatibility. The addition ratio of Ag SACs is controlled at 1-2 wt%, which significantly improves antibacterial and antiviral properties without affecting the impregnating adhesive's flowability and curing performance, achieving a balanced optimization between antibacterial and antiviral functions and resin curing performance. Attached Figure Description

[0026] Figure 1 Transmission electron microscopy (TEM) images of three samples prepared in Example 1: (a) ZIF-8, (b) Ti@ZIF-8, and (c) Ag SACs; and EDS surface scan images of Zn, N, Ti, O, and Ag elements in (di) Ag SACs.

[0027] Figure 2 Aberration-corrected electron micrograph of Ag SACs prepared in Example 1. Detailed Implementation

[0028] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0029] Unless otherwise specified, all materials and reagents used in this invention are commercially available.

[0030] This invention provides a silver single-atom antibacterial and antiviral material, its preparation method, and its application. Specific embodiments are as follows.

[0031] Example 1

[0032] A method for preparing a silver single-atom antibacterial and antiviral material includes:

[0033] Step 1: Dissolve 1 part of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) in 100 parts of methanol and stir until homogeneous. Dissolve 10 parts of 2-methylimidazolium (2-mim) in 100 parts of methanol, and then add it to the above zinc nitrate hexahydrate methanol solution. Stir vigorously at room temperature for 24 hours. After the reaction is complete, centrifuge at 8000 rpm for 12 minutes to collect the reaction product, and wash it three times with methanol. Place the collected white ZIF-8 powder in a vacuum drying oven and dry it at 60°C for 12 hours to obtain the final ZIF-8 product. A transmission electron microscope image of ZIF-8 is shown below. Figure 1 (a);

[0034] Step 2: Dissolve 1 part of cerium ammonium nitrate in 1000 parts of isopropanol and sonicate for 30 min to obtain a clear orange solution; then add 125 parts of titanium isopropoxide (IV) (TTIP, purity 97%) to the solution and stir magnetically for 30 min at room temperature. The resulting solution is the precursor solution.

[0035] Step 3: Add 1 part ZIF-8 to 20 parts precursor solution, sonicate for 1 h, then centrifuge, wash, and dry to obtain ZIF-8 material with an amorphous TiO2 transparent coating, i.e., TiO2@ZIF-8; the transmission electron microscope image of TiO2@ZIF-8 is shown below. Figure 1 (b);

[0036] Step 4: Weigh 1 part silver nitrate (AgNO3) and place it in a 50 mL beaker. Add 10 parts deionized water and stir with a glass rod until completely dissolved. Add dilute ammonia (5% by mass) dropwise to the above solution until the solution first becomes cloudy and then becomes clear again, obtaining a freshly prepared silver ammonia solution.

[0037] Step 5: Add 1 part TiO2@ZIF-8 to 100 parts H2O to obtain a TiO2@ZIF-8 dispersion. Add 1 part silver ammonia solution to the above TiO2@ZIF-8 dispersion, stir at 4℃ for 5 h, filter the resulting solution, remove the supernatant, wash the obtained precipitate three times with ultrapure water, and dry in an oven at 60℃ for 12 h. Then, pack the dried sample into a quartz tube and calcine at 200℃ for 12 h in a (N2 / H2=95:5) gas flow (40 mL min-1). Single-atom silver (Ag SACs) is obtained. Transmission electron microscopy image is shown below. Figure 1 (c) Figure 1 (d)-(i) are the EDS surface scan images of Zn, N, Ti, O and Ag elements corresponding to Ag SACs;

[0038] Figure 1As shown in (a), the synthesized ZIF-8 is a regular dodecahedron with a diameter of approximately 240 nm. Subsequently, a transparent amorphous TiO2 coating was constructed on the surface of the nano-ZIF-8 particles, successfully synthesizing Ti@ZIF-8, which is beneficial for the subsequent stability of single-atom silver. Finally, single-atom silver Ag SACs were successfully loaded onto the surface via pyrolysis. EDS analysis showed that Zn, N, Ti, O, and Ag elements were uniformly distributed. Figure 2 Aberration-corrected electron microscopy confirmed that silver atoms were dispersed in a monodisperse form on the Ti@ZIF-8 surface.

[0039] Example 2

[0040] The application of a silver single-atom antibacterial and antiviral material in the preparation of antibacterial and antiviral impregnated paper decorative panels includes:

[0041] (1) Formaldehyde, melamine and distilled water were added to a three-necked flask equipped with a reflux condenser and a stirring device. The molar ratio of formaldehyde to melamine was 2:1. Then, the pH was adjusted to 9 with NaOH solution. The reaction was stopped at 90°C when the water solubility ratio was 3, and melamine-formaldehyde resin with a weight average molecular weight of 500 was obtained.

[0042] The Ag SACs prepared in Example 1 were added to the prepared melamine-formaldehyde resin at a mass ratio of 1 wt% of the melamine-formaldehyde resin, and the mixture was stirred until homogeneous to obtain the impregnation adhesive.

[0043] (2) The raw material paper (30*15 cm) was immersed in a urea-formaldehyde resin aqueous solution (urea-formaldehyde resin with a weight-average molecular weight of 900 and a mass content of 55%) for 45 seconds, then removed and dried at 110℃ for 3 minutes to obtain paper I; then the antibacterial and antiviral coating was uniformly applied to paper I by a rubber roller, with a coating amount of 50 g / m 2 Dry at 110℃ for 2 minutes to obtain impregnated paper;

[0044] (3) Place the impregnated paper on the plywood (30*15 cm) and press it at 120℃ and 0.7 MPa for 7 min to obtain the antibacterial and antiviral impregnated paper decorative panel.

[0045] Example 3

[0046] In this embodiment, the amount of Ag SACs added is 1.5 wt% (by mass) of melamine-formaldehyde resin; the other conditions are the same as in Example 2.

[0047] Example 4

[0048] In this embodiment, the amount of Ag SACs added is 2wt% (by mass) of melamine-formaldehyde resin; the other conditions are the same as in Example 2.

[0049] To further illustrate the beneficial effects of the present invention, comparative examples are constructed as follows.

[0050] Comparative Example 1

[0051] In this comparative example, Ag SACs are omitted, and the impregnating adhesive is the melamine-formaldehyde resin prepared in step (1) of Example 2.

[0052] Comparative Example 2

[0053] In this comparative example, ZIF-8 was replaced with an equal mass of TiO2 (rutile, 400 nm particle size), and the other conditions were the same as in Example 3.

[0054] Comparative Example 3

[0055] In this comparative example, ZIF-8 was replaced with an equal mass of alumina (particle size 400 nm), and the other conditions were the same as in Example 3.

[0056] Comparative Example 4

[0057] In this comparative example, ZIF-8 was replaced with an equal mass of silicon dioxide (particle size 400nm), and the other conditions were the same as in Example 3.

[0058] Comparative Example 5

[0059] In this comparative example, ZIF-8 was replaced with an equal mass of cerium oxide (particle size 400 nm), and the other conditions were the same as in Example 3.

[0060] Comparative Example 6

[0061] In this comparative example, cerium ammonium nitrate in step (2) is omitted, and the other conditions are the same as in Example 3.

[0062] Comparative Example 7

[0063] In this comparative example, in step (7), the amount of Ag SACs added is 0.5wt% (by mass) of melamine-formaldehyde resin; the other conditions are the same as in Example 1.

[0064] The antibacterial properties of the decorative panels prepared in Examples 2-4 and Comparative Examples 1-7 were tested. The specific testing methods were carried out in accordance with LY / T1926-2020 "Testing and Grading of Antibacterial Properties of Wood-based Panels and Wood (Bamboo) Products". The results are shown in Table 1.

[0065] Table 1

[0066]

[0067] As shown in Table 1, the impregnated paper-faced plywood prepared with the silver single-atom antibacterial and antiviral material of this invention exhibits good antibacterial activity against both *Escherichia coli* and *Staphylococcus aureus*, reaching the Class I strong antibacterial standard. The antibacterial properties of the veneers prepared in Comparative Examples 1-7 are relatively poor. In Example 4, when the amount of Ag SACs added was relatively large, its antibacterial performance was the same as that in Example 3, proving that the amount added in Example 3 of this invention can already achieve the maximum antibacterial rate. Increasing the amount of Ag SACs added will increase production costs.

[0068] The antibacterial and durability properties of the decorative panels prepared using the silver single-atom antibacterial and antiviral materials of Examples 2-4 and Comparative Examples 1-7 were tested. The aging process during product use was simulated. Six specimens (50±1) mm × (50±1) mm were taken, and the perimeter of the specimens was waterproofed. Each specimen was washed 5000 times according to GB / T 9266 "Determination of Washability of Architectural Coatings". The washing direction should follow the texture of the surface material of the specimen. The washing medium was analytical laboratory water. After washing, the surface material was dried at room temperature until no visible water droplets remained. The antibacterial properties were then tested. The specific testing method was based on the group standard T / CNFPIA 3033-2023 "Antibacterial and Antiviral Decorative Artificial Boards". The results are shown in Table 2.

[0069] Table 2

[0070]

[0071] As shown in Table 2, the antibacterial properties of the decorative panel prepared by this invention did not decrease after 5000 washes, while the antibacterial properties of Comparative Examples 1-6 decreased significantly after washing. However, the antibacterial properties of Comparative Example 7 did not show a significant decrease after washing, demonstrating that the antibacterial agent prepared by this invention has a good long-lasting antibacterial effect. Furthermore, it can form a highly stable and reactive composite impregnating adhesive with the melamine-formaldehyde resin system.

[0072] The antiviral properties of the decorative panels prepared using Examples 2-4 and Comparative Examples 1-7 were tested. The specific testing method was carried out in accordance with ISO 21702:2019 "Tests for antiviral activity of plastics and nonporous surfaces". The antiviral properties against Influenza A virus (H3N2) were tested, and the results are shown in Table 3.

[0073] Table 3

[0074]

[0075] As shown in Table 3, the impregnated paper-faced plywood prepared by the impregnation adhesive of the present invention has a good inhibitory effect on influenza A virus H3N2, reaching 99.99%; while the veneer prepared in the comparative example has a poor inhibitory effect on H3N2.

[0076] In summary, this invention firmly anchors single-atom silver on the TiO2@ZIF-8 surface at the atomic level, effectively preventing silver agglomeration and migration; uniformly dispersing Ag SACs into the melamine-formaldehyde resin system forms a composite impregnating adhesive with high stability, high reactivity, and excellent interfacial compatibility, resulting in decorative panels with excellent antibacterial and antiviral functions.

[0077] The above description is a preferred embodiment of the present invention. For those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an antibacterial and antiviral impregnated paper decorative panel, characterized in that, include: (1) Add silver single-atom antibacterial and antiviral material to melamine-formaldehyde resin and mix evenly to obtain antibacterial and antiviral impregnation adhesive; the amount of silver single-atom antibacterial and antiviral material is 1wt%-2wt% of the amount of melamine-formaldehyde resin. (2) The raw paper is immersed in a urea-formaldehyde resin aqueous solution for 45 seconds, then removed and dried at 110°C for 3 minutes to obtain paper I; then the antibacterial and antiviral impregnating colloid is evenly coated onto paper I using a glue roller, with a coating amount of 50 g / m 2 Dry at 110℃ for 2 minutes to obtain impregnated paper; (3) Place the impregnated paper on the artificial board and press it at 120°C and 0.7 MPa for 7 minutes to obtain an antibacterial and antiviral impregnated paper decorative panel. The preparation method of the above-mentioned silver single-atom antibacterial and antiviral materials is as follows: Step 1: Preparation of ZIF-8; Step 2: Dissolve cerium ammonium nitrate in isopropanol and sonicate for 30 min to obtain a clear orange solution; Then titanium isopropoxide was added to the solution and magnetically stirred at room temperature for 30 min. The resulting solution is the precursor solution. The mass ratio of cerium ammonium nitrate, isopropanol and titanium isopropoxide is 1:1000:

125. Step 3: Add ZIF-8 to the precursor solution, sonicate for 1 h, then centrifuge, wash, and dry to obtain TiO2@ZIF-8; the mass ratio of ZIF-8 to the precursor solution is 1:

20. Step 4: Place silver nitrate in a 50 mL beaker, add deionized water, and stir with a glass rod until completely dissolved. Add dilute ammonia dropwise to the solution until it first becomes cloudy and then becomes clear again, yielding a freshly prepared silver ammonia solution. The mass ratio of silver nitrate to deionized water is 1:10; the volume concentration of the dilute ammonia is 5%. Step 5: Add TiO2@ZIF-8 to deionized water to obtain TiO2@ZIF-8 dispersion. Add silver ammonia solution to the above TiO2@ZIF-8 dispersion, stir at 4℃ for 5 h, filter, remove supernatant, wash the precipitate three times with ultrapure water, and dry in an oven at 60℃ for 12 h. Then, pack the dried sample into a quartz tube and calcine at 200℃ for 12 h in a mixed N2 and H2 gas flow to obtain silver single-atom antibacterial and antiviral materials Ag SACs. The mass ratio of TiO2@ZIF-8, deionized water, and silver ammonia solution is 1:100:

1.

2. The method according to claim 1, characterized in that, In step 5, the volume ratio of N2 to H2 in the N2 and H2 mixed gas flow is 95:5, and the flow rate of the N2 and H2 mixed gas flow is 40 mL / min. -1 .

3. The method according to claim 1, characterized in that, Step 1 specifically involves: dissolving 1 part of zinc nitrate hexahydrate in 100 parts of methanol and stirring until homogeneous to obtain a zinc nitrate methanol solution; dissolving 10 parts of 2-methylimidazole in 100 parts of methanol to obtain a 2-methylimidazole methanol solution; then adding the 2-methylimidazole methanol solution to the zinc nitrate methanol solution and stirring vigorously at room temperature for 24 hours; after the reaction is complete, centrifuging at 8000 rpm for 12 minutes to collect the reaction product, and washing it three times with methanol; placing the collected powder in a vacuum drying oven and drying it at 60°C for 12 hours to obtain ZIF-8.

4. The method according to claim 1, characterized in that, In step (2), the weight-average molecular weight of the urea-formaldehyde resin is 900, and the concentration of the urea-formaldehyde resin aqueous solution is 55 wt%; the impregnation amount of the urea-formaldehyde resin on the paper I is 110 g / m². 2 .

5. The method according to claim 1, characterized in that, In step (3), the engineered wood panel is a plywood panel.

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