Method for preventing discoloration of pine wood

Abstract

The present application relates to pine processing manufacturing technical field, disclose a kind of pine discoloration prevention method, including (1) soaking: pine is soaked in carbon nanomaterial solution, then soaked in bacteria liquid, finally soaked in metal ion solution;(2) drying: after removal, again in high pressure pulse electric field low-temperature slow baking is carried out, again in high pressure pulse electric field high-temperature drying;(3) coating: coating hydrophobic coating;The discoloration prevention method disclosed in the application can effectively prevent pine discoloration, at the same time, can prevent the invasion of bacteria, fungi, and the discoloration prevention method disclosed in the application does not affect the finishing performance of pine, also does not affect the gluing performance of pine basic unit, green and environmental protection, completely can satisfy the requirement of construction engineering, especially in the field of decoration.

Description

Technical Field

[0001] This invention relates to the technical field of pine wood processing and manufacturing, and in particular to a method for preventing pine wood from discoloring. Background Technology

[0002] Pine wood is an important raw material in my country's national economy, possessing a series of advantages such as light weight, high strength, sound absorption, insulation, beautiful grain, soft color, and good processing performance. It is a preferred material for construction, interior decoration, and furniture manufacturing, and is also the only renewable and recyclable biological resource among the four major building materials, playing a vital role in national economic development. However, due to its inherent structure and the influence of natural factors, pine wood is prone to discoloration and decay, directly affecting the quality of construction projects or decorative effects. Pine wood discoloration can be divided into two categories based on its causes: chemical discoloration, including tannin discoloration and oxidation discoloration; and fungal discoloration, including mold and blue stain.

[0003] Pine wood is widely used in my country and is a major material for civil engineering, furniture, interior decoration, and industrial packaging. The most common discoloration of pine wood is blue stain and mold. Pine wood can also discolor in the early stages of decay. Blue stain mainly occurs in the sapwood, ranging from light gray to dark blue to light black. On the surface or ends of boards and logs, discolored areas may appear as spots, streaks, and irregular patches. Under suitable conditions for fungal growth, all sapwood can discolor. Pine wood is a naturally synthesized organism, and because it contains certain nutrients such as starch, sugars, and proteins, it is susceptible to insect and fungal attacks. After blue stain fungi invade pine wood, they first multiply in tracheids or vessels. Then, the hyphae spread through the pits in the cell walls to cells containing soluble nutrients (such as starch and sugars), such as axial parenchyma cells or ray cells near vessels, absorbing various nutrients stored in the cells. In coniferous wood, the hyphae of blue stain fungi multiply along the wood ray cells into the interior of the pine wood. If the blue stain penetrates deep into the pine wood, the discoloration is difficult to remove and severely affects the processing and use of the pine wood.

[0004] Therefore, in order to increase the value of pine wood and extend its service life, targeted protective measures are needed. Summary of the Invention

[0005] Pine wood is widely used in my country and is a major material for civil engineering, furniture, interior decoration, and industrial packaging. The most common discoloration of pine wood is blue stain and mold. In order to improve the value of pine wood and extend its service life, targeted protective measures need to be taken.

[0006] To achieve the above objectives, the present invention proposes a method for preventing discoloration of pine wood, comprising:

[0007] (1) Soaking: Soak the pine wood in a carbon nanomaterial solution, then soak it in a bacterial solution, and finally soak it in a metal ion solution;

[0008] (2) Drying: After taking it out, place it in a high-voltage pulse electric field for low-temperature slow drying, and then place it in a high-voltage pulse electric field for high-temperature drying;

[0009] (3) Coating: Apply hydrophobic coating.

[0010] Furthermore, in step (1), the pine wood is soaked in the carbon nanomaterial solution for 1-1.5 hours, then soaked in the bacterial solution for 20-30 minutes, and finally soaked in the metal ion solution for 20-30 minutes.

[0011] Furthermore, the metal ion is at least one of zinc ion solution and magnesium ion solution.

[0012] Furthermore, the bacterial agent is a magnetotactic bacterial agent.

[0013] Furthermore, the nano-carbon material is at least one of carbon nanotubes and porous carbon.

[0014] Furthermore, in step (2), the high-voltage pulse electric field strength of the low-temperature slow drying is 10-15 kV / cm, the pulse width is 20-100 μs, and the number of pulses is 20-40; the high-voltage pulse electric field strength of the high-temperature drying is 10-15 kV / cm, the pulse width is 20-100 μs, and the number of pulses is 20-40.

[0015] Furthermore, the hydrophobic coating is a mixture of succinic acid resin, silica nanoparticles, and octadecyl alcohol polyoxyethylene ether.

[0016] Furthermore, the ratio of succinic acid resin, silica nanoparticles and octadecyl alcohol polyoxyethylene ether is 12-15:3-4:1.

[0017] Furthermore, before immersing the pine wood in the carbon nanomaterial solution, the pine wood is first frozen and then thawed.

[0018] Furthermore, before immersing the pine wood in the carbon nanomaterial solution, the pine wood is frozen and then thawed. Specifically, starting from room temperature, the temperature is lowered at a rate of 2°C / min until it reaches -18°C, at which point the cooling is stopped. After maintaining this temperature for 5-10 minutes, the pine wood is placed in a room temperature environment to thaw naturally.

[0019] Compared with existing technologies, its advantages are as follows:

[0020] This invention discloses a method for preventing discoloration of pine wood, which effectively prevents discoloration, bacterial and fungal invasion, and light-induced discoloration. Furthermore, the discoloration prevention method disclosed in this invention does not affect the finishing properties of pine wood or the gluing properties of the basic pine wood units. It is environmentally friendly and fully meets the requirements of construction projects, especially in the decoration field. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] The experimental materials used in the following examples and comparative examples are all commercially available products.

[0023] Example 1

[0024] Hydrophobic coating A is composed of succinic acid resin, silica nanoparticles and octadecyl alcohol polyoxyethylene ether in a volume ratio of 12:3:1.

[0025] Hydrophobic coating B is composed of succinic acid resin, silica nanoparticles and octadecyl alcohol polyoxyethylene ether in a volume ratio of 15:4:1.

[0026] Hydrophobic coating C is composed of succinic acid resin, silica nanoparticles and octadecyl alcohol polyoxyethylene ether in a volume ratio of 12:4:1.

[0027] The hydrophobic coating D is composed of succinic acid resin, silica nanoparticles and octadecyl alcohol polyoxyethylene ether in a volume ratio of 13:3:1.

[0028] Example 2

[0029] (1) Soaking

[0030] Pine wood was soaked in a carbon nanomaterial solution for 1 hour. Specifically, carbon nanomaterials were selected in this embodiment.

[0031] Then soak in a magnetotactic bacterial agent for 20 minutes. Specifically, in this example, ferrooxidizobacterium is selected.

[0032] Finally, immerse in a metal ion solution for 20 minutes. Specifically, in this embodiment, a zinc ion solution is used.

[0033] (2) Drying

[0034] After being removed, it was placed in a magnetic field with a low temperature and slow drying time of 6 hours. The high voltage pulse electric field strength was 10 kV / cm, the pulse width was 20 μs, and the number of pulses was 20.

[0035] Then, it is placed in a high-voltage pulsed electric field for high-temperature drying for 16 hours. The high-voltage pulsed electric field strength is 10kV / cm, the pulse width is 20μs, and the number of pulses is 20.

[0036] (3) Coating

[0037] Finally, a hydrophobic coating is applied. In this embodiment, hydrophobic coating A is selected.

[0038] Example 3

[0039] (1) Soaking

[0040] Pine wood was soaked in a carbon nanomaterial solution for 1.5 hours. Specifically, the carbon nanomaterial used in this embodiment was porous carbon.

[0041] Then soak in a magnetotactic bacterial agent for 30 minutes. Specifically, in this example, ferrooxidizobacterium is selected.

[0042] Finally, immerse in a metal ion solution for 30 minutes. Specifically, in this embodiment, a zinc ion solution is used.

[0043] (2) Drying

[0044] After being removed, it was placed in a magnetic field with a low temperature and slow drying time of 8 hours. The high voltage pulse electric field strength was 15 kV / cm, the pulse width was 100 μs, and the number of pulses was 40.

[0045] Then, it is placed in a high-voltage pulsed electric field for high-temperature drying for 20 hours. The high-voltage pulsed electric field strength is 15kV / cm, the pulse width is 100μs, and the number of pulses is 40.

[0046] (3) Coating

[0047] Finally, a hydrophobic coating is applied. In this embodiment, hydrophobic coating B is selected.

[0048] Example 4

[0049] (1) Soaking

[0050] Pine wood was soaked in a carbon nanomaterial solution for 1.3 hours. Specifically, the carbon nanomaterials used in this embodiment were carbon nanotubes and porous carbon.

[0051] Then soak in a magnetotactic bacterial agent for 25 minutes. Specifically, in this example, ferrooxidizobacterium is selected.

[0052] Finally, immerse in a metal ion solution for 25 minutes. Specifically, in this embodiment, a magnesium ion solution is used.

[0053] (2) Drying

[0054] After being removed, the sample was placed in a magnetic field with a low temperature and slow drying time of 7 hours. The high voltage pulse electric field strength was 13 kV / cm, the pulse width was 60 μs, and the number of pulses was 30.

[0055] Then, it is placed in a high-voltage pulsed electric field for high-temperature drying for 18 hours. The high-voltage pulsed electric field strength is 12kV / cm, the pulse width is 70μs, and the number of pulses is 30.

[0056] (3) Coating

[0057] Finally, a hydrophobic coating is applied. In this embodiment, hydrophobic coating C is selected.

[0058] Example 5

[0059] (1) Soaking

[0060] Pine wood was soaked in a carbon nanomaterial solution for 13 hours. Specifically, carbon nanomaterials were selected in this embodiment.

[0061] Then soak in a magnetotactic bacterial agent for 20 minutes. Specifically, in this example, ferrooxidizobacterium is selected.

[0062] Finally, immerse in a metal ion solution for 30 minutes. Specifically, in this embodiment, a magnesium ion solution is used.

[0063] (2) Drying

[0064] After being removed, it was placed in a magnetic field with a low temperature and slow drying time of 8 hours. The high voltage pulse electric field strength was 15 kV / cm, the pulse width was 20 μs, and the number of pulses was 25.

[0065] Then, it is placed in a high-voltage pulsed electric field for high-temperature drying for 18 hours. The high-voltage pulsed electric field strength is 11kV / cm, the pulse width is 100μs, and the number of pulses is 20.

[0066] (3) Coating

[0067] Finally, a hydrophobic coating is applied. In this embodiment, hydrophobic coating D is selected.

[0068] Example 6

[0069] (1) Soaking

[0070] Pine wood was soaked in a carbon nanomaterial solution for 1.5 hours. Specifically, the carbon nanomaterial used in this embodiment was porous carbon.

[0071] Then soak in a magnetotactic bacterial agent for 20 minutes. Specifically, in this example, ferrooxidizobacterium is selected.

[0072] Finally, it is immersed in a metal ion solution for 30 minutes. Specifically, in this embodiment, zinc ion solution and magnesium ion solution are selected.

[0073] (2) Drying

[0074] After being removed, it was placed in a magnetic field with a low temperature and slow drying time of 8 hours. The high voltage pulse electric field strength was 10 kV / cm, the pulse width was 100 μs, and the number of pulses was 20.

[0075] Then, it is placed in a high-voltage pulsed electric field for high-temperature drying for 20 hours. The high-voltage pulsed electric field strength is 10kV / cm, the pulse width is 50μs, and the number of pulses is 25.

[0076] (3) Coating

[0077] Finally, a hydrophobic coating is applied. In this embodiment, hydrophobic coating A is selected.

[0078] Example 7

[0079] (1) Soaking

[0080] Pine wood was soaked in a carbon nanomaterial solution for 1.5 hours. Specifically, the carbon nanomaterials used in this embodiment were carbon nanotubes and porous carbon.

[0081] Then soak in a magnetotactic bacterial agent for 28 minutes. Specifically, in this example, ferrooxidizobacterium is selected.

[0082] Finally, it is immersed in a metal ion solution for 26 minutes. Specifically, in this embodiment, zinc ion solution and magnesium ion solution are selected.

[0083] (2) Drying

[0084] After being removed, it was placed in a magnetic field with a low temperature and slow drying time of 8 hours. The high voltage pulse electric field strength was 10 kV / cm, the pulse width was 20 μs, and the number of pulses was 20.

[0085] Then, it is placed in a high-voltage pulsed electric field for high-temperature drying for 20 hours. The high-voltage pulsed electric field strength is 15kV / cm, the pulse width is 90μs, and the number of pulses is 20.

[0086] (3) Coating

[0087] Finally, a hydrophobic coating is applied. In this embodiment, hydrophobic coating B is selected.

[0088] Example 8

[0089] (1) Freezing

[0090] The pine wood was cooled from room temperature at a rate of 2°C / min until it reached -18°C. The cooling was then stopped and maintained for 5 minutes. Finally, the pine wood was placed at room temperature to thaw naturally.

[0091] (2) Soaking

[0092] The thawed pine wood was soaked in a carbon nanomaterial solution for 1 hour. Specifically, the carbon nanomaterial used in this embodiment is carbon nanotubes.

[0093] Then soak in a magnetotactic bacterial agent for 20 minutes. Specifically, in this example, ferrooxidizobacterium is selected.

[0094] Finally, immerse in a metal ion solution for 20 minutes. Specifically, in this embodiment, a zinc ion solution is used.

[0095] (3) Drying

[0096] After being removed, it was placed in a magnetic field with a low temperature and slow drying time of 6 hours. The high voltage pulse electric field strength was 10 kV / cm, the pulse width was 20 μs, and the number of pulses was 20.

[0097] Then, it is placed in a high-voltage pulsed electric field for high-temperature drying for 16 hours. The high-voltage pulsed electric field strength is 10kV / cm, the pulse width is 20μs, and the number of pulses is 20.

[0098] (4) Coating

[0099] Finally, a hydrophobic coating is applied. In this embodiment, hydrophobic coating A is selected.

[0100] Example 9

[0101] (1) Freezing

[0102] The pine wood was cooled from room temperature at a rate of 2°C / min until it reached -18°C. The cooling was then stopped and maintained for 10 minutes. Finally, the pine wood was placed at room temperature to thaw naturally.

[0103] (2) Soaking

[0104] Pine wood was soaked in a carbon nanomaterial solution for 1.5 hours. Specifically, the carbon nanomaterial used in this embodiment was porous carbon.

[0105] Then soak in a magnetotactic bacterial agent for 30 minutes. Specifically, in this example, ferrooxidizobacterium is selected.

[0106] Finally, immerse in a metal ion solution for 30 minutes. Specifically, in this embodiment, a zinc ion solution is used.

[0107] (2) Drying

[0108] After being removed, it was placed in a magnetic field with a low temperature and slow drying time of 8 hours. The high voltage pulse electric field strength was 15 kV / cm, the pulse width was 100 μs, and the number of pulses was 40.

[0109] Then, it is placed in a high-voltage pulsed electric field for high-temperature drying for 20 hours. The high-voltage pulsed electric field strength is 15kV / cm, the pulse width is 100μs, and the number of pulses is 40.

[0110] (3) Coating

[0111] Finally, a hydrophobic coating is applied. In this embodiment, hydrophobic coating B is selected.

[0112] Comparative Example 1

[0113] (1) Soaking

[0114] Pine wood was soaked in a carbon nanomaterial solution for 1 hour. Specifically, carbon nanomaterials were used in this comparative example.

[0115] Then soak in a magnetotactic bacterial agent for 20 minutes. Specifically, in this comparative example, ferrooxidizobacterium was selected.

[0116] Finally, immerse in a metal ion solution for 20 minutes. Specifically, zinc ion solution was used in this comparative example.

[0117] (2) Drying

[0118] After being removed, it was placed in a magnetic field with a low temperature and slow drying time of 6 hours. The high voltage pulse electric field strength was 10 kV / cm, the pulse width was 20 μs, and the number of pulses was 20.

[0119] Then, it is placed in a high-voltage pulsed electric field for high-temperature drying for 16 hours. The high-voltage pulsed electric field strength is 10kV / cm, the pulse width is 20μs, and the number of pulses is 20.

[0120] Comparative Example 2

[0121] (1) Soaking

[0122] Pine wood was soaked in a carbon nanomaterial solution for 1.5 hours. Specifically, the carbon nanomaterial used in this comparative example was porous carbon.

[0123] Then soak in a magnetotactic bacterial agent for 30 minutes. Specifically, in this comparative example, ferrooxidizobacterium was selected.

[0124] Finally, immerse in a metal ion solution for 30 minutes. Specifically, zinc ion solution was used in this comparative example.

[0125] (2) Drying

[0126] After being removed, it was placed in a magnetic field with a low temperature and slow drying time of 8 hours. The high voltage pulse electric field strength was 15 kV / cm, the pulse width was 100 μs, and the number of pulses was 40.

[0127] Then, it is placed in a high-voltage pulsed electric field for high-temperature drying for 20 hours. The high-voltage pulsed electric field strength is 15kV / cm, the pulse width is 100μs, and the number of pulses is 40.

[0128] Comparative Example 3

[0129] (1) Soaking

[0130] Pine wood was soaked in a carbon nanomaterial solution for 1.3 hours. Specifically, the carbon nanomaterials used in this comparative example were carbon nanotubes and porous carbon.

[0131] Then soak in a magnetotactic bacterial agent for 25 minutes. Specifically, in this comparative example, ferrooxidizobacterium was selected.

[0132] Finally, immerse in a metal ion solution for 25 minutes. Specifically, a magnesium ion solution was used in this comparative example.

[0133] (2) Drying

[0134] After being removed, the sample was placed in a magnetic field with a low temperature and slow drying time of 7 hours. The high voltage pulse electric field strength was 13 kV / cm, the pulse width was 60 μs, and the number of pulses was 30.

[0135] Then, it is placed in a high-voltage pulsed electric field for high-temperature drying for 18 hours. The high-voltage pulsed electric field strength is 12kV / cm, the pulse width is 70μs, and the number of pulses is 30.

[0136] Comparative Example 4

[0137] (1) Soaking

[0138] Pine wood was soaked in a carbon nanomaterial solution for 1 hour. Specifically, the carbon nanomaterials used in this comparative example were carbon nanotubes and porous carbon.

[0139] Soak in Escherichia coli inoculum for 20 minutes. Specifically, in this comparative example, Thiobacillus ferrooxidans was selected.

[0140] Finally, immerse in a metal ion solution for 20 minutes. Specifically, a copper ion solution was used in this comparative example.

[0141] (2) Drying

[0142] After being removed, it was placed in a magnetic field with a low temperature and slow drying time of 6 hours. The high voltage pulse electric field strength was 10 kV / cm, the pulse width was 20 μs, and the number of pulses was 20.

[0143] Then, it is placed in a high-voltage pulsed electric field for high-temperature drying for 16 hours. The high-voltage pulsed electric field strength is 10kV / cm, the pulse width is 20μs, and the number of pulses is 20.

[0144] (3) Coating

[0145] Finally, a hydrophobic coating is applied. In this comparative example, hydrophobic coating A is used.

[0146] Comparative Example 5

[0147] (1) Soaking

[0148] Pine wood was soaked in a carbon nanomaterial solution for 1.5 hours. Specifically, carbon nanomaterials were used in this comparative example.

[0149] Then soak in a magnetotactic bacterial agent for 30 minutes. Specifically, in this comparative example, ferrooxidizobacterium was selected.

[0150] Finally, immerse in a metal ion solution for 30 minutes. Specifically, zinc ion solution was used in this comparative example.

[0151] (2) Drying

[0152] After being removed, it was placed in a magnetic field with a low temperature and slow drying time of 8 hours. The high voltage pulse electric field strength was 15 kV / cm, the pulse width was 100 μs, and the number of pulses was 40.

[0153] Then, it is placed in a high-voltage pulsed electric field for high-temperature drying for 20 hours. The high-voltage pulsed electric field strength is 15kV / cm, the pulse width is 100μs, and the number of pulses is 40.

[0154] (3) Coating

[0155] Finally, a hydrophobic coating is applied. In this embodiment, hydrophobic coating A is selected.

[0156] Comparative Example 6

[0157] (1) Soaking

[0158] Pine wood was soaked in a carbon nanomaterial solution for 1.5 hours. Specifically, porous carbon was used as the carbon nanomaterial in this comparative example.

[0159] Soak in Escherichia coli inoculum for 20 minutes. Specifically, in this comparative example, Thiobacillus ferrooxidans was selected.

[0160] Finally, immerse in a metal ion solution for 30 minutes. Specifically, zinc ion solution and magnesium ion solution were used in this comparative example.

[0161] (2) Drying

[0162] Remove and then slowly dry at a low temperature for 8 hours;

[0163] Then dry at high temperature for 20 hours.

[0164] (3) Coating

[0165] Finally, a hydrophobic coating is applied. In this comparative example, hydrophobic coating B was selected.

[0166] Results analysis:

[0167] Following the method outlined in national standard GB / T18261-2013 "Test Methods for the Prevention of Mold and Discoloration Fungi in Wood by Antifungal Agents," experiments were conducted on the wood treated with blue stain fungi and molds in Examples 1-9 and Comparative Examples 1-6 to prevent mold and blue stain. The pine wood from Examples 1-9 and Comparative Examples 1-6 showed no surface fungal growth and no internal blue stain development, indicating that treatment with the method described in these embodiments of the invention effectively inhibits both blue stain fungi and molds within the wood.

[0168] Light irradiation experiments were conducted on the wood treated in Examples 1-9 and Comparative Examples 1-6 according to the method in GB / T23987-2009. Using a UVA340 lamp as the light source, the wood was placed at a temperature of 60°C with an irradiance of 0.89 W / m (340 nm) for 168 hours of continuous irradiation. The wood in Examples 1-9 did not show discoloration, while the wood in Comparative Examples 1-6 showed slight discoloration. The results indicate that the anti-discoloration method of Examples 1-9 is superior to that of Comparative Examples 1-6 and can more effectively prevent light-induced discoloration.

[0169] This invention involves immersing pine wood in a carbon nanomaterial solution, causing the wood to develop micropores and increasing its surface area. This provides more sites for adsorbing substances. The bacteria in the fungicide utilize the microporous structure as habitats. Placing the pine wood soaked in the fungicide in a metal ion solution allows the bacteria to adsorb metal ions. The interaction between the bacteria and metal ions produces nanomaterials with specific functions and structures, providing a protective layer for the pine wood. This protective layer not only prevents the invasion of bacteria and fungi but also improves the chemical stability of the pine wood, protecting it from chemical corrosion and degradation, while increasing its wear resistance. Furthermore, this protective layer has excellent ultraviolet (UV) absorption properties, helping to prevent color changes when the wood is exposed to sunlight, thus contributing to the protection of the wood from UV radiation damage.

[0170] Due to the hydrophobic properties of octadecyl alcohol polyoxyethylene ether, combining it with succinic acid resin and silica nanoparticles can form a coating with excellent hydrophobic properties. This gives the coating strong water and moisture resistance, helping to protect the coated object from the effects of humid environments. Silica nanoparticles are a high-hardness, wear-resistant material; adding them to the coating can increase its hardness, thereby improving the wear resistance of the coated object. Chemical corrosion resistance: Succinic acid resin has a certain degree of chemical stability, which can enhance the coating's resistance to some chemical corrosion, protecting the coated object from corrosive substances. High temperature resistance: Succinic acid resin generally has a certain degree of high temperature resistance, allowing the coating to remain stable in high-temperature environments, making it suitable for applications under high-temperature conditions. This invention, by rationally adjusting the component ratio of the hydrophobic coating, can maintain the transparency of the coating, making it suitable for applications requiring maintained surface transparency. Among the components used, succinic acid resin and silica nanoparticles are relatively environmentally friendly materials, which can reduce the coating's environmental impact. Meanwhile, by selecting appropriate formulations and processing methods, this invention can ensure good adhesion performance of the coating, guaranteeing its firm attachment to the surface of the coated object. Furthermore, the hydrophobic coating has a microstructure that causes some light scattering and absorption, thereby reducing light intensity; the hydrophobic coating can also reduce surface reflection, thus preventing light-induced discoloration of pine wood.

[0171] Magnetic fields can inhibit the growth of microorganisms in wood. Drying in a magnetic field can reduce the survival rate of microorganisms absorbed by the wood, thereby lowering the risk of pine wood rot and decay caused by the microorganisms.

[0172] Freezing can effectively kill some pests, bacteria, fungi, and other microorganisms in wood, eliminating interference from pre-existing microorganisms in pine wood for subsequent steps. During freezing, moisture in the wood may exist in the form of solid ice crystals, and the formation of these ice crystals can cause changes in the wood's internal microstructure. The formation of ice crystals may lead to changes in internal pressure, thereby increasing the porosity of the wood to some extent. Upon thawing, the ice crystals melt and release moisture, which may lead to the formation or expansion of these pores. Due to the formation of more pores, frozen wood may have higher water absorption capacity. Although this increases the risk of pine wood decay to some extent, this invention solves the problem of "increased risk of pine wood decay" by soaking the wood with carbon nanomaterials, microbial agents, and metal ions after freezing and thawing. Simultaneously, the increased pore size allows carbon nanomaterials, microbial agents, and metal ions to penetrate the pine wood more quickly and efficiently.

[0173] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preventing discoloration of pine wood, characterized in that, include: (1) Soaking: Soak the pine wood in a carbon nanomaterial solution, then in a bacterial solution, and finally in a metal ion solution; The metal ion is at least one of zinc ion solution and magnesium ion solution; The carbon nanomaterial is at least one of carbon nanotubes and porous carbon. Before immersing the pine wood in the carbon nanomaterial solution, the pine wood is first frozen and then thawed. (2) Drying: After taking it out, place it in a high-voltage pulse electric field for low-temperature slow drying, and then place it in a high-voltage pulse electric field for high-temperature drying; (3) Coating: Applying a hydrophobic coating; The bacterial agent used in the bacterial solution is *Thiobacillus ferrooxidans*. The hydrophobic coating is a mixture of succinic acid resin, silica nanoparticles and octadecyl alcohol polyoxyethylene ether.

2. The method for preventing discoloration of pine wood according to claim 1, characterized in that, In step (1), the pine wood is soaked in the carbon nanomaterial solution for 1-1.5 hours, then soaked in the bacterial solution for 20-30 minutes, and finally soaked in the metal ion solution for 20-30 minutes.

3. The method for preventing discoloration of pine wood according to claim 1, characterized in that, In (2), the high-voltage pulse electric field strength of the low-temperature slow drying is 10-15kV / cm, the pulse width is 20-100μs, and the number of pulses is 20-40; the high-voltage pulse electric field strength of the high-temperature drying is 10-15kV / cm, the pulse width is 20-100μs, and the number of pulses is 20-40.

4. The method for preventing discoloration of pine wood according to claim 1, characterized in that, The ratio of succinic acid resin, silica nanoparticles and octadecyl alcohol polyoxyethylene ether is 12-15:3-4:

1.

5. The method for preventing discoloration of pine wood according to claim 4, characterized in that, Before immersing the pine wood in the carbon nanomaterial solution, the pine wood is frozen and then thawed. Specifically, starting from room temperature, the temperature is lowered at a rate of 2℃ / min until it reaches -18℃. After maintaining this temperature for 5-10 minutes, the pine wood is placed at room temperature for natural thawing.